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Re: [patch 05/15] Basic MIPS support

To: linux-mips@linux-mips.org
Subject: Re: [patch 05/15] Basic MIPS support
From: Ralf Baechle <ralf@linux-mips.org>
Date: Mon, 1 Aug 2005 11:19:33 +0100
In-reply-to: <resend.5.2972005.trini@kernel.crashing.org>
Original-recipient: rfc822;linux-mips@linux-mips.org
References: <resend.4.2972005.trini@kernel.crashing.org> <1.2972005.trini@kernel.crashing.org> <resend.5.2972005.trini@kernel.crashing.org>
Sender: linux-mips-bounce@linux-mips.org
User-agent: Mutt/1.4.2.1i
Forwarding this as a heads up.  Who cares about kgdb may want to start
working on the necessary bits as the patchset from below will be in 2.6.13.

  Ralf

On Fri, Jul 29, 2005 at 02:19:35PM -0700, Tom Rini wrote:

> CC: Manish Lachwani <mlachwani@mvista.com>, Ralf Baechle <ralf@linux-mips.org>
> This adds basic support to the MIPS architecture as well as support
> specifically for the MIPS Malta and SiByte 1250-SWARM (32 and 64bit), all from
> Manish Lachwani.  This looks like it should work on anything with an
> 8250-compatible uart, and be fairly easy to convert other boards custom uarts
> as needed.
> 
> ---
> 
>  linux-2.6.13-rc3-trini/arch/mips/Kconfig.debug                   |   19 
>  linux-2.6.13-rc3-trini/arch/mips/kernel/Makefile                 |    3 
>  linux-2.6.13-rc3-trini/arch/mips/kernel/irq.c                    |   32 
>  linux-2.6.13-rc3-trini/arch/mips/kernel/kgdb-jmp.c               |   62 
>  linux-2.6.13-rc3-trini/arch/mips/kernel/kgdb-setjmp.S            |   23 
>  linux-2.6.13-rc3-trini/arch/mips/kernel/kgdb.c                   |  292 ++
>  linux-2.6.13-rc3-trini/arch/mips/kernel/kgdb_handler.S           |   58 
>  linux-2.6.13-rc3-trini/arch/mips/kernel/traps.c                  |   26 
>  linux-2.6.13-rc3-trini/arch/mips/mips-boards/generic/Makefile    |    1 
>  linux-2.6.13-rc3-trini/arch/mips/mips-boards/generic/init.c      |   62 
>  linux-2.6.13-rc3-trini/arch/mips/mips-boards/malta/malta_setup.c |    8 
>  linux-2.6.13-rc3-trini/arch/mips/mm/extable.c                    |    7 
>  linux-2.6.13-rc3-trini/arch/mips/sibyte/cfe/setup.c              |   14 
>  linux-2.6.13-rc3-trini/arch/mips/sibyte/sb1250/Makefile          |    1 
>  linux-2.6.13-rc3-trini/arch/mips/sibyte/sb1250/irq.c             |   57 
>  linux-2.6.13-rc3-trini/arch/mips/sibyte/sb1250/irq_handler.S     |    2 
>  linux-2.6.13-rc3-trini/arch/mips/sibyte/sb1250/kgdb_sibyte.c     |  164 +
>  linux-2.6.13-rc3-trini/arch/mips/sibyte/swarm/Makefile           |    2 
>  linux-2.6.13-rc3-trini/include/asm-mips/kdebug.h                 |   47 
>  linux-2.6.13-rc3-trini/include/asm-mips/kgdb.h                   |   22 
>  linux-2.6.13-rc3-trini/lib/Kconfig.debug                         |    7 
>  linux-2.6.13-rc3/arch/mips/kernel/gdb-low.S                      |  370 ---
>  linux-2.6.13-rc3/arch/mips/kernel/gdb-stub.c                     | 1091 
> ----------
>  linux-2.6.13-rc3/arch/mips/sibyte/swarm/dbg_io.c                 |   76 
>  24 files changed, 729 insertions(+), 1717 deletions(-)
> 
> diff -puN arch/mips/Kconfig.debug~mips-lite arch/mips/Kconfig.debug
> --- linux-2.6.13-rc3/arch/mips/Kconfig.debug~mips-lite        2005-07-29 
> 11:55:31.000000000 -0700
> +++ linux-2.6.13-rc3-trini/arch/mips/Kconfig.debug    2005-07-29 
> 11:55:31.000000000 -0700
> @@ -27,25 +27,6 @@ config DEBUG_STACK_USAGE
>  
>         This option will slow down process creation somewhat.
>  
> -config KGDB
> -     bool "Remote GDB kernel debugging"
> -     depends on DEBUG_KERNEL
> -     select DEBUG_INFO
> -     help
> -       If you say Y here, it will be possible to remotely debug the MIPS
> -       kernel using gdb. This enlarges your kernel image disk size by
> -       several megabytes and requires a machine with more than 16 MB,
> -       better 32 MB RAM to avoid excessive linking time. This is only
> -       useful for kernel hackers. If unsure, say N.
> -
> -config GDB_CONSOLE
> -     bool "Console output to GDB"
> -     depends on KGDB
> -     help
> -       If you are using GDB for remote debugging over a serial port and
> -       would like kernel messages to be formatted into GDB $O packets so
> -       that GDB prints them as program output, say 'Y'.
> -
>  config SB1XXX_CORELIS
>       bool "Corelis Debugger"
>       depends on SIBYTE_SB1xxx_SOC
> diff -L arch/mips/kernel/gdb-low.S -puN arch/mips/kernel/gdb-low.S~mips-lite 
> /dev/null
> --- linux-2.6.13-rc3/arch/mips/kernel/gdb-low.S
> +++ /dev/null 2005-07-25 10:57:32.312383000 -0700
> @@ -1,370 +0,0 @@
> -/*
> - * gdb-low.S contains the low-level trap handler for the GDB stub.
> - *
> - * Copyright (C) 1995 Andreas Busse
> - */
> -#include <linux/config.h>
> -#include <linux/sys.h>
> -
> -#include <asm/asm.h>
> -#include <asm/errno.h>
> -#include <asm/mipsregs.h>
> -#include <asm/regdef.h>
> -#include <asm/stackframe.h>
> -#include <asm/gdb-stub.h>
> -
> -#ifdef CONFIG_MIPS32
> -#define DMFC0        mfc0
> -#define DMTC0        mtc0
> -#define LDC1 lwc1
> -#define SDC1 lwc1
> -#endif
> -#ifdef CONFIG_MIPS64
> -#define DMFC0        dmfc0
> -#define DMTC0        dmtc0
> -#define LDC1 ldc1
> -#define SDC1 ldc1
> -#endif
> -
> -/*
> - * [jsun] We reserves about 2x GDB_FR_SIZE in stack.  The lower (addressed)
> - * part is used to store registers and passed to exception handler.
> - * The upper part is reserved for "call func" feature where gdb client
> - * saves some of the regs, setups call frame and passes args.
> - *
> - * A trace shows about 200 bytes are used to store about half of all regs.
> - * The rest should be big enough for frame setup and passing args.
> - */
> -
> -/*
> - * The low level trap handler
> - */
> -             .align  5
> -             NESTED(trap_low, GDB_FR_SIZE, sp)
> -             .set    noat
> -             .set    noreorder
> -
> -             mfc0    k0, CP0_STATUS
> -             sll     k0, 3                   /* extract cu0 bit */
> -             bltz    k0, 1f
> -             move    k1, sp
> -
> -             /*
> -              * Called from user mode, go somewhere else.
> -              */
> -             lui     k1, %hi(saved_vectors)
> -             mfc0    k0, CP0_CAUSE
> -             andi    k0, k0, 0x7c
> -             add     k1, k1, k0
> -             lw      k0, %lo(saved_vectors)(k1)
> -             jr      k0
> -             nop
> -1:
> -             move    k0, sp
> -             subu    sp, k1, GDB_FR_SIZE*2   # see comment above
> -             LONG_S  k0, GDB_FR_REG29(sp)
> -             LONG_S  $2, GDB_FR_REG2(sp)
> -
> -/*
> - * First save the CP0 and special registers
> - */
> -
> -             mfc0    v0, CP0_STATUS
> -             LONG_S  v0, GDB_FR_STATUS(sp)
> -             mfc0    v0, CP0_CAUSE
> -             LONG_S  v0, GDB_FR_CAUSE(sp)
> -             DMFC0   v0, CP0_EPC
> -             LONG_S  v0, GDB_FR_EPC(sp)
> -             DMFC0   v0, CP0_BADVADDR
> -             LONG_S  v0, GDB_FR_BADVADDR(sp)
> -             mfhi    v0
> -             LONG_S  v0, GDB_FR_HI(sp)
> -             mflo    v0
> -             LONG_S  v0, GDB_FR_LO(sp)
> -
> -/*
> - * Now the integer registers
> - */
> -
> -             LONG_S  zero, GDB_FR_REG0(sp)           /* I know... */
> -             LONG_S  $1, GDB_FR_REG1(sp)
> -             /* v0 already saved */
> -             LONG_S  $3, GDB_FR_REG3(sp)
> -             LONG_S  $4, GDB_FR_REG4(sp)
> -             LONG_S  $5, GDB_FR_REG5(sp)
> -             LONG_S  $6, GDB_FR_REG6(sp)
> -             LONG_S  $7, GDB_FR_REG7(sp)
> -             LONG_S  $8, GDB_FR_REG8(sp)
> -             LONG_S  $9, GDB_FR_REG9(sp)
> -             LONG_S  $10, GDB_FR_REG10(sp)
> -             LONG_S  $11, GDB_FR_REG11(sp)
> -             LONG_S  $12, GDB_FR_REG12(sp)
> -             LONG_S  $13, GDB_FR_REG13(sp)
> -             LONG_S  $14, GDB_FR_REG14(sp)
> -             LONG_S  $15, GDB_FR_REG15(sp)
> -             LONG_S  $16, GDB_FR_REG16(sp)
> -             LONG_S  $17, GDB_FR_REG17(sp)
> -             LONG_S  $18, GDB_FR_REG18(sp)
> -             LONG_S  $19, GDB_FR_REG19(sp)
> -             LONG_S  $20, GDB_FR_REG20(sp)
> -             LONG_S  $21, GDB_FR_REG21(sp)
> -             LONG_S  $22, GDB_FR_REG22(sp)
> -             LONG_S  $23, GDB_FR_REG23(sp)
> -             LONG_S  $24, GDB_FR_REG24(sp)
> -             LONG_S  $25, GDB_FR_REG25(sp)
> -             LONG_S  $26, GDB_FR_REG26(sp)
> -             LONG_S  $27, GDB_FR_REG27(sp)
> -             LONG_S  $28, GDB_FR_REG28(sp)
> -             /* sp already saved */
> -             LONG_S  $30, GDB_FR_REG30(sp)
> -             LONG_S  $31, GDB_FR_REG31(sp)
> -
> -             CLI                             /* disable interrupts */
> -
> -/*
> - * Followed by the floating point registers
> - */
> -             mfc0    v0, CP0_STATUS          /* FPU enabled? */
> -             srl     v0, v0, 16
> -             andi    v0, v0, (ST0_CU1 >> 16)
> -
> -             beqz    v0,2f                   /* disabled, skip */
> -              nop
> -
> -             SDC1    $0, GDB_FR_FPR0(sp)
> -             SDC1    $1, GDB_FR_FPR1(sp)
> -             SDC1    $2, GDB_FR_FPR2(sp)
> -             SDC1    $3, GDB_FR_FPR3(sp)
> -             SDC1    $4, GDB_FR_FPR4(sp)
> -             SDC1    $5, GDB_FR_FPR5(sp)
> -             SDC1    $6, GDB_FR_FPR6(sp)
> -             SDC1    $7, GDB_FR_FPR7(sp)
> -             SDC1    $8, GDB_FR_FPR8(sp)
> -             SDC1    $9, GDB_FR_FPR9(sp)
> -             SDC1    $10, GDB_FR_FPR10(sp)
> -             SDC1    $11, GDB_FR_FPR11(sp)
> -             SDC1    $12, GDB_FR_FPR12(sp)
> -             SDC1    $13, GDB_FR_FPR13(sp)
> -             SDC1    $14, GDB_FR_FPR14(sp)
> -             SDC1    $15, GDB_FR_FPR15(sp)
> -             SDC1    $16, GDB_FR_FPR16(sp)
> -             SDC1    $17, GDB_FR_FPR17(sp)
> -             SDC1    $18, GDB_FR_FPR18(sp)
> -             SDC1    $19, GDB_FR_FPR19(sp)
> -             SDC1    $20, GDB_FR_FPR20(sp)
> -             SDC1    $21, GDB_FR_FPR21(sp)
> -             SDC1    $22, GDB_FR_FPR22(sp)
> -             SDC1    $23, GDB_FR_FPR23(sp)
> -             SDC1    $24, GDB_FR_FPR24(sp)
> -             SDC1    $25, GDB_FR_FPR25(sp)
> -             SDC1    $26, GDB_FR_FPR26(sp)
> -             SDC1    $27, GDB_FR_FPR27(sp)
> -             SDC1    $28, GDB_FR_FPR28(sp)
> -             SDC1    $29, GDB_FR_FPR29(sp)
> -             SDC1    $30, GDB_FR_FPR30(sp)
> -             SDC1    $31, GDB_FR_FPR31(sp)
> -
> -/*
> - * FPU control registers
> - */
> -
> -             cfc1    v0, CP1_STATUS
> -             LONG_S  v0, GDB_FR_FSR(sp)
> -             cfc1    v0, CP1_REVISION
> -             LONG_S  v0, GDB_FR_FIR(sp)
> -
> -/*
> - * Current stack frame ptr
> - */
> -
> -2:
> -             LONG_S  sp, GDB_FR_FRP(sp)
> -
> -/*
> - * CP0 registers (R4000/R4400 unused registers skipped)
> - */
> -
> -             mfc0    v0, CP0_INDEX
> -             LONG_S  v0, GDB_FR_CP0_INDEX(sp)
> -             mfc0    v0, CP0_RANDOM
> -             LONG_S  v0, GDB_FR_CP0_RANDOM(sp)
> -             DMFC0   v0, CP0_ENTRYLO0
> -             LONG_S  v0, GDB_FR_CP0_ENTRYLO0(sp)
> -             DMFC0   v0, CP0_ENTRYLO1
> -             LONG_S  v0, GDB_FR_CP0_ENTRYLO1(sp)
> -             DMFC0   v0, CP0_CONTEXT
> -             LONG_S  v0, GDB_FR_CP0_CONTEXT(sp)
> -             mfc0    v0, CP0_PAGEMASK
> -             LONG_S  v0, GDB_FR_CP0_PAGEMASK(sp)
> -             mfc0    v0, CP0_WIRED
> -             LONG_S  v0, GDB_FR_CP0_WIRED(sp)
> -             DMFC0   v0, CP0_ENTRYHI
> -             LONG_S  v0, GDB_FR_CP0_ENTRYHI(sp)
> -             mfc0    v0, CP0_PRID
> -             LONG_S  v0, GDB_FR_CP0_PRID(sp)
> -
> -             .set    at
> -
> -/*
> - * Continue with the higher level handler
> - */
> -
> -             move    a0,sp
> -
> -             jal     handle_exception
> -              nop
> -
> -/*
> - * Restore all writable registers, in reverse order
> - */
> -
> -             .set    noat
> -
> -             LONG_L  v0, GDB_FR_CP0_ENTRYHI(sp)
> -             LONG_L  v1, GDB_FR_CP0_WIRED(sp)
> -             DMTC0   v0, CP0_ENTRYHI
> -             mtc0    v1, CP0_WIRED
> -             LONG_L  v0, GDB_FR_CP0_PAGEMASK(sp)
> -             LONG_L  v1, GDB_FR_CP0_ENTRYLO1(sp)
> -             mtc0    v0, CP0_PAGEMASK
> -             DMTC0   v1, CP0_ENTRYLO1
> -             LONG_L  v0, GDB_FR_CP0_ENTRYLO0(sp)
> -             LONG_L  v1, GDB_FR_CP0_INDEX(sp)
> -             DMTC0   v0, CP0_ENTRYLO0
> -             LONG_L  v0, GDB_FR_CP0_CONTEXT(sp)
> -             mtc0    v1, CP0_INDEX
> -             DMTC0   v0, CP0_CONTEXT
> -
> -
> -/*
> - * Next, the floating point registers
> - */
> -             mfc0    v0, CP0_STATUS          /* check if the FPU is enabled 
> */
> -             srl     v0, v0, 16
> -             andi    v0, v0, (ST0_CU1 >> 16)
> -
> -             beqz    v0, 3f                  /* disabled, skip */
> -              nop
> -
> -             LDC1    $31, GDB_FR_FPR31(sp)
> -             LDC1    $30, GDB_FR_FPR30(sp)
> -             LDC1    $29, GDB_FR_FPR29(sp)
> -             LDC1    $28, GDB_FR_FPR28(sp)
> -             LDC1    $27, GDB_FR_FPR27(sp)
> -             LDC1    $26, GDB_FR_FPR26(sp)
> -             LDC1    $25, GDB_FR_FPR25(sp)
> -             LDC1    $24, GDB_FR_FPR24(sp)
> -             LDC1    $23, GDB_FR_FPR23(sp)
> -             LDC1    $22, GDB_FR_FPR22(sp)
> -             LDC1    $21, GDB_FR_FPR21(sp)
> -             LDC1    $20, GDB_FR_FPR20(sp)
> -             LDC1    $19, GDB_FR_FPR19(sp)
> -             LDC1    $18, GDB_FR_FPR18(sp)
> -             LDC1    $17, GDB_FR_FPR17(sp)
> -             LDC1    $16, GDB_FR_FPR16(sp)
> -             LDC1    $15, GDB_FR_FPR15(sp)
> -             LDC1    $14, GDB_FR_FPR14(sp)
> -             LDC1    $13, GDB_FR_FPR13(sp)
> -             LDC1    $12, GDB_FR_FPR12(sp)
> -             LDC1    $11, GDB_FR_FPR11(sp)
> -             LDC1    $10, GDB_FR_FPR10(sp)
> -             LDC1    $9, GDB_FR_FPR9(sp)
> -             LDC1    $8, GDB_FR_FPR8(sp)
> -             LDC1    $7, GDB_FR_FPR7(sp)
> -             LDC1    $6, GDB_FR_FPR6(sp)
> -             LDC1    $5, GDB_FR_FPR5(sp)
> -             LDC1    $4, GDB_FR_FPR4(sp)
> -             LDC1    $3, GDB_FR_FPR3(sp)
> -             LDC1    $2, GDB_FR_FPR2(sp)
> -             LDC1    $1, GDB_FR_FPR1(sp)
> -             LDC1    $0, GDB_FR_FPR0(sp)
> -
> -/*
> - * Now the CP0 and integer registers
> - */
> -
> -3:
> -             mfc0    t0, CP0_STATUS
> -             ori     t0, 0x1f
> -             xori    t0, 0x1f
> -             mtc0    t0, CP0_STATUS
> -
> -             LONG_L  v0, GDB_FR_STATUS(sp)
> -             LONG_L  v1, GDB_FR_EPC(sp)
> -             mtc0    v0, CP0_STATUS
> -             DMTC0   v1, CP0_EPC
> -             LONG_L  v0, GDB_FR_HI(sp)
> -             LONG_L  v1, GDB_FR_LO(sp)
> -             mthi    v0
> -             mtlo    v1
> -             LONG_L  $31, GDB_FR_REG31(sp)
> -             LONG_L  $30, GDB_FR_REG30(sp)
> -             LONG_L  $28, GDB_FR_REG28(sp)
> -             LONG_L  $27, GDB_FR_REG27(sp)
> -             LONG_L  $26, GDB_FR_REG26(sp)
> -             LONG_L  $25, GDB_FR_REG25(sp)
> -             LONG_L  $24, GDB_FR_REG24(sp)
> -             LONG_L  $23, GDB_FR_REG23(sp)
> -             LONG_L  $22, GDB_FR_REG22(sp)
> -             LONG_L  $21, GDB_FR_REG21(sp)
> -             LONG_L  $20, GDB_FR_REG20(sp)
> -             LONG_L  $19, GDB_FR_REG19(sp)
> -             LONG_L  $18, GDB_FR_REG18(sp)
> -             LONG_L  $17, GDB_FR_REG17(sp)
> -             LONG_L  $16, GDB_FR_REG16(sp)
> -             LONG_L  $15, GDB_FR_REG15(sp)
> -             LONG_L  $14, GDB_FR_REG14(sp)
> -             LONG_L  $13, GDB_FR_REG13(sp)
> -             LONG_L  $12, GDB_FR_REG12(sp)
> -             LONG_L  $11, GDB_FR_REG11(sp)
> -             LONG_L  $10, GDB_FR_REG10(sp)
> -             LONG_L  $9, GDB_FR_REG9(sp)
> -             LONG_L  $8, GDB_FR_REG8(sp)
> -             LONG_L  $7, GDB_FR_REG7(sp)
> -             LONG_L  $6, GDB_FR_REG6(sp)
> -             LONG_L  $5, GDB_FR_REG5(sp)
> -             LONG_L  $4, GDB_FR_REG4(sp)
> -             LONG_L  $3, GDB_FR_REG3(sp)
> -             LONG_L  $2, GDB_FR_REG2(sp)
> -             LONG_L  $1, GDB_FR_REG1(sp)
> -#if defined(CONFIG_CPU_R3000) || defined(CONFIG_CPU_TX39XX)
> -             LONG_L  k0, GDB_FR_EPC(sp)
> -             LONG_L  $29, GDB_FR_REG29(sp)           /* Deallocate stack */
> -             jr      k0
> -             rfe
> -#else
> -             LONG_L  sp, GDB_FR_REG29(sp)            /* Deallocate stack */
> -
> -             .set    mips3
> -             eret
> -             .set    mips0
> -#endif
> -             .set    at
> -             .set    reorder
> -             END(trap_low)
> -
> -LEAF(kgdb_read_byte)
> -4:           lb      t0, (a0)
> -             sb      t0, (a1)
> -             li      v0, 0
> -             jr      ra
> -             .section __ex_table,"a"
> -             PTR     4b, kgdbfault
> -             .previous
> -             END(kgdb_read_byte)
> -
> -LEAF(kgdb_write_byte)
> -5:           sb      a0, (a1)
> -             li      v0, 0
> -             jr      ra
> -             .section __ex_table,"a"
> -             PTR     5b, kgdbfault
> -             .previous
> -             END(kgdb_write_byte)
> -
> -             .type   kgdbfault@function
> -             .ent    kgdbfault
> -
> -kgdbfault:   li      v0, -EFAULT
> -             jr      ra
> -             .end    kgdbfault
> diff -L arch/mips/kernel/gdb-stub.c -puN 
> arch/mips/kernel/gdb-stub.c~mips-lite /dev/null
> --- linux-2.6.13-rc3/arch/mips/kernel/gdb-stub.c
> +++ /dev/null 2005-07-25 10:57:32.312383000 -0700
> @@ -1,1091 +0,0 @@
> -/*
> - *  arch/mips/kernel/gdb-stub.c
> - *
> - *  Originally written by Glenn Engel, Lake Stevens Instrument Division
> - *
> - *  Contributed by HP Systems
> - *
> - *  Modified for SPARC by Stu Grossman, Cygnus Support.
> - *
> - *  Modified for Linux/MIPS (and MIPS in general) by Andreas Busse
> - *  Send complaints, suggestions etc. to <andy@waldorf-gmbh.de>
> - *
> - *  Copyright (C) 1995 Andreas Busse
> - *
> - *  Copyright (C) 2003 MontaVista Software Inc.
> - *  Author: Jun Sun, jsun@mvista.com or jsun@junsun.net
> - */
> -
> -/*
> - *  To enable debugger support, two things need to happen.  One, a
> - *  call to set_debug_traps() is necessary in order to allow any breakpoints
> - *  or error conditions to be properly intercepted and reported to gdb.
> - *  Two, a breakpoint needs to be generated to begin communication.  This
> - *  is most easily accomplished by a call to breakpoint().  Breakpoint()
> - *  simulates a breakpoint by executing a BREAK instruction.
> - *
> - *
> - *    The following gdb commands are supported:
> - *
> - * command          function                               Return value
> - *
> - *    g             return the value of the CPU registers  hex data or ENN
> - *    G             set the value of the CPU registers     OK or ENN
> - *
> - *    mAA..AA,LLLL  Read LLLL bytes at address AA..AA      hex data or ENN
> - *    MAA..AA,LLLL: Write LLLL bytes at address AA.AA      OK or ENN
> - *
> - *    c             Resume at current address              SNN   ( signal NN)
> - *    cAA..AA       Continue at address AA..AA             SNN
> - *
> - *    s             Step one instruction                   SNN
> - *    sAA..AA       Step one instruction from AA..AA       SNN
> - *
> - *    k             kill
> - *
> - *    ?             What was the last sigval ?             SNN   (signal NN)
> - *
> - *    bBB..BB            Set baud rate to BB..BB                OK or BNN, 
> then sets
> - *                                                      baud rate
> - *
> - * All commands and responses are sent with a packet which includes a
> - * checksum.  A packet consists of
> - *
> - * $<packet info>#<checksum>.
> - *
> - * where
> - * <packet info> :: <characters representing the command or response>
> - * <checksum>    :: < two hex digits computed as modulo 256 sum of 
> <packetinfo>>
> - *
> - * When a packet is received, it is first acknowledged with either '+' or 
> '-'.
> - * '+' indicates a successful transfer.  '-' indicates a failed transfer.
> - *
> - * Example:
> - *
> - * Host:                  Reply:
> - * $m0,10#2a               +$00010203040506070809101112131415#42
> - *
> - *
> - *  ==============
> - *  MORE EXAMPLES:
> - *  ==============
> - *
> - *  For reference -- the following are the steps that one
> - *  company took (RidgeRun Inc) to get remote gdb debugging
> - *  going. In this scenario the host machine was a PC and the
> - *  target platform was a Galileo EVB64120A MIPS evaluation
> - *  board.
> - *
> - *  Step 1:
> - *  First download gdb-5.0.tar.gz from the internet.
> - *  and then build/install the package.
> - *
> - *  Example:
> - *    $ tar zxf gdb-5.0.tar.gz
> - *    $ cd gdb-5.0
> - *    $ ./configure --target=mips-linux-elf
> - *    $ make
> - *    $ install
> - *    $ which mips-linux-elf-gdb
> - *    /usr/local/bin/mips-linux-elf-gdb
> - *
> - *  Step 2:
> - *  Configure linux for remote debugging and build it.
> - *
> - *  Example:
> - *    $ cd ~/linux
> - *    $ make menuconfig <go to "Kernel Hacking" and turn on remote debugging>
> - *    $ make
> - *
> - *  Step 3:
> - *  Download the kernel to the remote target and start
> - *  the kernel running. It will promptly halt and wait
> - *  for the host gdb session to connect. It does this
> - *  since the "Kernel Hacking" option has defined
> - *  CONFIG_KGDB which in turn enables your calls
> - *  to:
> - *     set_debug_traps();
> - *     breakpoint();
> - *
> - *  Step 4:
> - *  Start the gdb session on the host.
> - *
> - *  Example:
> - *    $ mips-linux-elf-gdb vmlinux
> - *    (gdb) set remotebaud 115200
> - *    (gdb) target remote /dev/ttyS1
> - *    ...at this point you are connected to
> - *       the remote target and can use gdb
> - *       in the normal fasion. Setting
> - *       breakpoints, single stepping,
> - *       printing variables, etc.
> - */
> -#include <linux/config.h>
> -#include <linux/string.h>
> -#include <linux/kernel.h>
> -#include <linux/signal.h>
> -#include <linux/sched.h>
> -#include <linux/mm.h>
> -#include <linux/console.h>
> -#include <linux/init.h>
> -#include <linux/smp.h>
> -#include <linux/spinlock.h>
> -#include <linux/slab.h>
> -#include <linux/reboot.h>
> -
> -#include <asm/asm.h>
> -#include <asm/cacheflush.h>
> -#include <asm/mipsregs.h>
> -#include <asm/pgtable.h>
> -#include <asm/system.h>
> -#include <asm/gdb-stub.h>
> -#include <asm/inst.h>
> -
> -/*
> - * external low-level support routines
> - */
> -
> -extern int putDebugChar(char c);    /* write a single character      */
> -extern char getDebugChar(void);     /* read and return a single char */
> -extern void trap_low(void);
> -
> -/*
> - * breakpoint and test functions
> - */
> -extern void breakpoint(void);
> -extern void breakinst(void);
> -extern void async_breakpoint(void);
> -extern void async_breakinst(void);
> -extern void adel(void);
> -
> -/*
> - * local prototypes
> - */
> -
> -static void getpacket(char *buffer);
> -static void putpacket(char *buffer);
> -static int computeSignal(int tt);
> -static int hex(unsigned char ch);
> -static int hexToInt(char **ptr, int *intValue);
> -static int hexToLong(char **ptr, long *longValue);
> -static unsigned char *mem2hex(char *mem, char *buf, int count, int 
> may_fault);
> -void handle_exception(struct gdb_regs *regs);
> -
> -int kgdb_enabled;
> -
> -/*
> - * spin locks for smp case
> - */
> -static spinlock_t kgdb_lock = SPIN_LOCK_UNLOCKED;
> -static spinlock_t kgdb_cpulock[NR_CPUS] = { [0 ... NR_CPUS-1] = 
> SPIN_LOCK_UNLOCKED};
> -
> -/*
> - * BUFMAX defines the maximum number of characters in inbound/outbound 
> buffers
> - * at least NUMREGBYTES*2 are needed for register packets
> - */
> -#define BUFMAX 2048
> -
> -static char input_buffer[BUFMAX];
> -static char output_buffer[BUFMAX];
> -static int initialized;      /* !0 means we've been initialized */
> -static int kgdb_started;
> -static const char hexchars[]="0123456789abcdef";
> -
> -/* Used to prevent crashes in memory access.  Note that they'll crash anyway 
> if
> -   we haven't set up fault handlers yet... */
> -int kgdb_read_byte(unsigned char *address, unsigned char *dest);
> -int kgdb_write_byte(unsigned char val, unsigned char *dest);
> -
> -/*
> - * Convert ch from a hex digit to an int
> - */
> -static int hex(unsigned char ch)
> -{
> -     if (ch >= 'a' && ch <= 'f')
> -             return ch-'a'+10;
> -     if (ch >= '0' && ch <= '9')
> -             return ch-'0';
> -     if (ch >= 'A' && ch <= 'F')
> -             return ch-'A'+10;
> -     return -1;
> -}
> -
> -/*
> - * scan for the sequence $<data>#<checksum>
> - */
> -static void getpacket(char *buffer)
> -{
> -     unsigned char checksum;
> -     unsigned char xmitcsum;
> -     int i;
> -     int count;
> -     unsigned char ch;
> -
> -     do {
> -             /*
> -              * wait around for the start character,
> -              * ignore all other characters
> -              */
> -             while ((ch = (getDebugChar() & 0x7f)) != '$') ;
> -
> -             checksum = 0;
> -             xmitcsum = -1;
> -             count = 0;
> -
> -             /*
> -              * now, read until a # or end of buffer is found
> -              */
> -             while (count < BUFMAX) {
> -                     ch = getDebugChar();
> -                     if (ch == '#')
> -                             break;
> -                     checksum = checksum + ch;
> -                     buffer[count] = ch;
> -                     count = count + 1;
> -             }
> -
> -             if (count >= BUFMAX)
> -                     continue;
> -
> -             buffer[count] = 0;
> -
> -             if (ch == '#') {
> -                     xmitcsum = hex(getDebugChar() & 0x7f) << 4;
> -                     xmitcsum |= hex(getDebugChar() & 0x7f);
> -
> -                     if (checksum != xmitcsum)
> -                             putDebugChar('-');      /* failed checksum */
> -                     else {
> -                             putDebugChar('+'); /* successful transfer */
> -
> -                             /*
> -                              * if a sequence char is present,
> -                              * reply the sequence ID
> -                              */
> -                             if (buffer[2] == ':') {
> -                                     putDebugChar(buffer[0]);
> -                                     putDebugChar(buffer[1]);
> -
> -                                     /*
> -                                      * remove sequence chars from buffer
> -                                      */
> -                                     count = strlen(buffer);
> -                                     for (i=3; i <= count; i++)
> -                                             buffer[i-3] = buffer[i];
> -                             }
> -                     }
> -             }
> -     }
> -     while (checksum != xmitcsum);
> -}
> -
> -/*
> - * send the packet in buffer.
> - */
> -static void putpacket(char *buffer)
> -{
> -     unsigned char checksum;
> -     int count;
> -     unsigned char ch;
> -
> -     /*
> -      * $<packet info>#<checksum>.
> -      */
> -
> -     do {
> -             putDebugChar('$');
> -             checksum = 0;
> -             count = 0;
> -
> -             while ((ch = buffer[count]) != 0) {
> -                     if (!(putDebugChar(ch)))
> -                             return;
> -                     checksum += ch;
> -                     count += 1;
> -             }
> -
> -             putDebugChar('#');
> -             putDebugChar(hexchars[checksum >> 4]);
> -             putDebugChar(hexchars[checksum & 0xf]);
> -
> -     }
> -     while ((getDebugChar() & 0x7f) != '+');
> -}
> -
> -
> -/*
> - * Convert the memory pointed to by mem into hex, placing result in buf.
> - * Return a pointer to the last char put in buf (null), in case of mem fault,
> - * return 0.
> - * may_fault is non-zero if we are reading from arbitrary memory, but is 
> currently
> - * not used.
> - */
> -static unsigned char *mem2hex(char *mem, char *buf, int count, int may_fault)
> -{
> -     unsigned char ch;
> -
> -     while (count-- > 0) {
> -             if (kgdb_read_byte(mem++, &ch) != 0)
> -                     return 0;
> -             *buf++ = hexchars[ch >> 4];
> -             *buf++ = hexchars[ch & 0xf];
> -     }
> -
> -     *buf = 0;
> -
> -     return buf;
> -}
> -
> -/*
> - * convert the hex array pointed to by buf into binary to be placed in mem
> - * return a pointer to the character AFTER the last byte written
> - * may_fault is non-zero if we are reading from arbitrary memory, but is 
> currently
> - * not used.
> - */
> -static char *hex2mem(char *buf, char *mem, int count, int binary, int 
> may_fault)
> -{
> -     int i;
> -     unsigned char ch;
> -
> -     for (i=0; i<count; i++)
> -     {
> -             if (binary) {
> -                     ch = *buf++;
> -                     if (ch == 0x7d)
> -                             ch = 0x20 ^ *buf++;
> -             }
> -             else {
> -                     ch = hex(*buf++) << 4;
> -                     ch |= hex(*buf++);
> -             }
> -             if (kgdb_write_byte(ch, mem++) != 0)
> -                     return 0;
> -     }
> -
> -     return mem;
> -}
> -
> -/*
> - * This table contains the mapping between SPARC hardware trap types, and
> - * signals, which are primarily what GDB understands.  It also indicates
> - * which hardware traps we need to commandeer when initializing the stub.
> - */
> -static struct hard_trap_info {
> -     unsigned char tt;               /* Trap type code for MIPS R3xxx and 
> R4xxx */
> -     unsigned char signo;            /* Signal that we map this trap into */
> -} hard_trap_info[] = {
> -     { 6, SIGBUS },                  /* instruction bus error */
> -     { 7, SIGBUS },                  /* data bus error */
> -     { 9, SIGTRAP },                 /* break */
> -     { 10, SIGILL },                 /* reserved instruction */
> -/*   { 11, SIGILL },         */      /* CPU unusable */
> -     { 12, SIGFPE },                 /* overflow */
> -     { 13, SIGTRAP },                /* trap */
> -     { 14, SIGSEGV },                /* virtual instruction cache coherency 
> */
> -     { 15, SIGFPE },                 /* floating point exception */
> -     { 23, SIGSEGV },                /* watch */
> -     { 31, SIGSEGV },                /* virtual data cache coherency */
> -     { 0, 0}                         /* Must be last */
> -};
> -
> -/* Save the normal trap handlers for user-mode traps. */
> -void *saved_vectors[32];
> -
> -/*
> - * Set up exception handlers for tracing and breakpoints
> - */
> -void set_debug_traps(void)
> -{
> -     struct hard_trap_info *ht;
> -     unsigned long flags;
> -     unsigned char c;
> -
> -     local_irq_save(flags);
> -     for (ht = hard_trap_info; ht->tt && ht->signo; ht++)
> -             saved_vectors[ht->tt] = set_except_vector(ht->tt, trap_low);
> -
> -     putDebugChar('+'); /* 'hello world' */
> -     /*
> -      * In case GDB is started before us, ack any packets
> -      * (presumably "$?#xx") sitting there.
> -      */
> -     while((c = getDebugChar()) != '$');
> -     while((c = getDebugChar()) != '#');
> -     c = getDebugChar(); /* eat first csum byte */
> -     c = getDebugChar(); /* eat second csum byte */
> -     putDebugChar('+'); /* ack it */
> -
> -     initialized = 1;
> -     local_irq_restore(flags);
> -}
> -
> -void restore_debug_traps(void)
> -{
> -     struct hard_trap_info *ht;
> -     unsigned long flags;
> -
> -     local_irq_save(flags);
> -     for (ht = hard_trap_info; ht->tt && ht->signo; ht++)
> -             set_except_vector(ht->tt, saved_vectors[ht->tt]);
> -     local_irq_restore(flags);
> -}
> -
> -/*
> - * Convert the MIPS hardware trap type code to a Unix signal number.
> - */
> -static int computeSignal(int tt)
> -{
> -     struct hard_trap_info *ht;
> -
> -     for (ht = hard_trap_info; ht->tt && ht->signo; ht++)
> -             if (ht->tt == tt)
> -                     return ht->signo;
> -
> -     return SIGHUP;          /* default for things we don't know about */
> -}
> -
> -/*
> - * While we find nice hex chars, build an int.
> - * Return number of chars processed.
> - */
> -static int hexToInt(char **ptr, int *intValue)
> -{
> -     int numChars = 0;
> -     int hexValue;
> -
> -     *intValue = 0;
> -
> -     while (**ptr) {
> -             hexValue = hex(**ptr);
> -             if (hexValue < 0)
> -                     break;
> -
> -             *intValue = (*intValue << 4) | hexValue;
> -             numChars ++;
> -
> -             (*ptr)++;
> -     }
> -
> -     return (numChars);
> -}
> -
> -static int hexToLong(char **ptr, long *longValue)
> -{
> -     int numChars = 0;
> -     int hexValue;
> -
> -     *longValue = 0;
> -
> -     while (**ptr) {
> -             hexValue = hex(**ptr);
> -             if (hexValue < 0)
> -                     break;
> -
> -             *longValue = (*longValue << 4) | hexValue;
> -             numChars ++;
> -
> -             (*ptr)++;
> -     }
> -
> -     return numChars;
> -}
> -
> -
> -#if 0
> -/*
> - * Print registers (on target console)
> - * Used only to debug the stub...
> - */
> -void show_gdbregs(struct gdb_regs * regs)
> -{
> -     /*
> -      * Saved main processor registers
> -      */
> -     printk("$0 : %08lx %08lx %08lx %08lx %08lx %08lx %08lx %08lx\n",
> -            regs->reg0, regs->reg1, regs->reg2, regs->reg3,
> -               regs->reg4, regs->reg5, regs->reg6, regs->reg7);
> -     printk("$8 : %08lx %08lx %08lx %08lx %08lx %08lx %08lx %08lx\n",
> -            regs->reg8, regs->reg9, regs->reg10, regs->reg11,
> -               regs->reg12, regs->reg13, regs->reg14, regs->reg15);
> -     printk("$16: %08lx %08lx %08lx %08lx %08lx %08lx %08lx %08lx\n",
> -            regs->reg16, regs->reg17, regs->reg18, regs->reg19,
> -               regs->reg20, regs->reg21, regs->reg22, regs->reg23);
> -     printk("$24: %08lx %08lx %08lx %08lx %08lx %08lx %08lx %08lx\n",
> -            regs->reg24, regs->reg25, regs->reg26, regs->reg27,
> -            regs->reg28, regs->reg29, regs->reg30, regs->reg31);
> -
> -     /*
> -      * Saved cp0 registers
> -      */
> -     printk("epc  : %08lx\nStatus: %08lx\nCause : %08lx\n",
> -            regs->cp0_epc, regs->cp0_status, regs->cp0_cause);
> -}
> -#endif /* dead code */
> -
> -/*
> - * We single-step by setting breakpoints. When an exception
> - * is handled, we need to restore the instructions hoisted
> - * when the breakpoints were set.
> - *
> - * This is where we save the original instructions.
> - */
> -static struct gdb_bp_save {
> -     unsigned long addr;
> -     unsigned int val;
> -} step_bp[2];
> -
> -#define BP 0x0000000d  /* break opcode */
> -
> -/*
> - * Set breakpoint instructions for single stepping.
> - */
> -static void single_step(struct gdb_regs *regs)
> -{
> -     union mips_instruction insn;
> -     unsigned long targ;
> -     int is_branch, is_cond, i;
> -
> -     targ = regs->cp0_epc;
> -     insn.word = *(unsigned int *)targ;
> -     is_branch = is_cond = 0;
> -
> -     switch (insn.i_format.opcode) {
> -     /*
> -      * jr and jalr are in r_format format.
> -      */
> -     case spec_op:
> -             switch (insn.r_format.func) {
> -             case jalr_op:
> -             case jr_op:
> -                     targ = *(&regs->reg0 + insn.r_format.rs);
> -                     is_branch = 1;
> -                     break;
> -             }
> -             break;
> -
> -     /*
> -      * This group contains:
> -      * bltz_op, bgez_op, bltzl_op, bgezl_op,
> -      * bltzal_op, bgezal_op, bltzall_op, bgezall_op.
> -      */
> -     case bcond_op:
> -             is_branch = is_cond = 1;
> -             targ += 4 + (insn.i_format.simmediate << 2);
> -             break;
> -
> -     /*
> -      * These are unconditional and in j_format.
> -      */
> -     case jal_op:
> -     case j_op:
> -             is_branch = 1;
> -             targ += 4;
> -             targ >>= 28;
> -             targ <<= 28;
> -             targ |= (insn.j_format.target << 2);
> -             break;
> -
> -     /*
> -      * These are conditional.
> -      */
> -     case beq_op:
> -     case beql_op:
> -     case bne_op:
> -     case bnel_op:
> -     case blez_op:
> -     case blezl_op:
> -     case bgtz_op:
> -     case bgtzl_op:
> -     case cop0_op:
> -     case cop1_op:
> -     case cop2_op:
> -     case cop1x_op:
> -             is_branch = is_cond = 1;
> -             targ += 4 + (insn.i_format.simmediate << 2);
> -             break;
> -     }
> -
> -     if (is_branch) {
> -             i = 0;
> -             if (is_cond && targ != (regs->cp0_epc + 8)) {
> -                     step_bp[i].addr = regs->cp0_epc + 8;
> -                     step_bp[i++].val = *(unsigned *)(regs->cp0_epc + 8);
> -                     *(unsigned *)(regs->cp0_epc + 8) = BP;
> -             }
> -             step_bp[i].addr = targ;
> -             step_bp[i].val  = *(unsigned *)targ;
> -             *(unsigned *)targ = BP;
> -     } else {
> -             step_bp[0].addr = regs->cp0_epc + 4;
> -             step_bp[0].val  = *(unsigned *)(regs->cp0_epc + 4);
> -             *(unsigned *)(regs->cp0_epc + 4) = BP;
> -     }
> -}
> -
> -/*
> - *  If asynchronously interrupted by gdb, then we need to set a breakpoint
> - *  at the interrupted instruction so that we wind up stopped with a
> - *  reasonable stack frame.
> - */
> -static struct gdb_bp_save async_bp;
> -
> -/*
> - * Swap the interrupted EPC with our asynchronous breakpoint routine.
> - * This is safer than stuffing the breakpoint in-place, since no cache
> - * flushes (or resulting smp_call_functions) are required.  The
> - * assumption is that only one CPU will be handling asynchronous bp's,
> - * and only one can be active at a time.
> - */
> -extern spinlock_t smp_call_lock;
> -void set_async_breakpoint(unsigned long *epc)
> -{
> -     /* skip breaking into userland */
> -     if ((*epc & 0x80000000) == 0)
> -             return;
> -
> -     /* avoid deadlock if someone is make IPC */
> -     if (spin_is_locked(&smp_call_lock))
> -             return;
> -
> -     async_bp.addr = *epc;
> -     *epc = (unsigned long)async_breakpoint;
> -}
> -
> -void kgdb_wait(void *arg)
> -{
> -     unsigned flags;
> -     int cpu = smp_processor_id();
> -
> -     local_irq_save(flags);
> -
> -     spin_lock(&kgdb_cpulock[cpu]);
> -     spin_unlock(&kgdb_cpulock[cpu]);
> -
> -     local_irq_restore(flags);
> -}
> -
> -
> -/*
> - * This function does all command processing for interfacing to gdb.  It
> - * returns 1 if you should skip the instruction at the trap address, 0
> - * otherwise.
> - */
> -void handle_exception (struct gdb_regs *regs)
> -{
> -     int trap;                       /* Trap type */
> -     int sigval;
> -     long addr;
> -     int length;
> -     char *ptr;
> -     unsigned long *stack;
> -     int i;
> -     int bflag = 0;
> -
> -     kgdb_started = 1;
> -
> -     /*
> -      * acquire the big kgdb spinlock
> -      */
> -     if (!spin_trylock(&kgdb_lock)) {
> -             /* 
> -              * some other CPU has the lock, we should go back to 
> -              * receive the gdb_wait IPC
> -              */
> -             return;
> -     }
> -
> -     /*
> -      * If we're in async_breakpoint(), restore the real EPC from
> -      * the breakpoint.
> -      */
> -     if (regs->cp0_epc == (unsigned long)async_breakinst) {
> -             regs->cp0_epc = async_bp.addr;
> -             async_bp.addr = 0;
> -     }
> -
> -     /* 
> -      * acquire the CPU spinlocks
> -      */
> -     for (i = num_online_cpus()-1; i >= 0; i--)
> -             if (spin_trylock(&kgdb_cpulock[i]) == 0)
> -                     panic("kgdb: couldn't get cpulock %d\n", i);
> -
> -     /*
> -      * force other cpus to enter kgdb
> -      */
> -     smp_call_function(kgdb_wait, NULL, 0, 0);
> -
> -     /*
> -      * If we're in breakpoint() increment the PC
> -      */
> -     trap = (regs->cp0_cause & 0x7c) >> 2;
> -     if (trap == 9 && regs->cp0_epc == (unsigned long)breakinst)
> -             regs->cp0_epc += 4;
> -
> -     /*
> -      * If we were single_stepping, restore the opcodes hoisted
> -      * for the breakpoint[s].
> -      */
> -     if (step_bp[0].addr) {
> -             *(unsigned *)step_bp[0].addr = step_bp[0].val;
> -             step_bp[0].addr = 0;
> -
> -             if (step_bp[1].addr) {
> -                     *(unsigned *)step_bp[1].addr = step_bp[1].val;
> -                     step_bp[1].addr = 0;
> -             }
> -     }
> -
> -     stack = (long *)regs->reg29;                    /* stack ptr */
> -     sigval = computeSignal(trap);
> -
> -     /*
> -      * reply to host that an exception has occurred
> -      */
> -     ptr = output_buffer;
> -
> -     /*
> -      * Send trap type (converted to signal)
> -      */
> -     *ptr++ = 'T';
> -     *ptr++ = hexchars[sigval >> 4];
> -     *ptr++ = hexchars[sigval & 0xf];
> -
> -     /*
> -      * Send Error PC
> -      */
> -     *ptr++ = hexchars[REG_EPC >> 4];
> -     *ptr++ = hexchars[REG_EPC & 0xf];
> -     *ptr++ = ':';
> -     ptr = mem2hex((char *)&regs->cp0_epc, ptr, sizeof(long), 0);
> -     *ptr++ = ';';
> -
> -     /*
> -      * Send frame pointer
> -      */
> -     *ptr++ = hexchars[REG_FP >> 4];
> -     *ptr++ = hexchars[REG_FP & 0xf];
> -     *ptr++ = ':';
> -     ptr = mem2hex((char *)&regs->reg30, ptr, sizeof(long), 0);
> -     *ptr++ = ';';
> -
> -     /*
> -      * Send stack pointer
> -      */
> -     *ptr++ = hexchars[REG_SP >> 4];
> -     *ptr++ = hexchars[REG_SP & 0xf];
> -     *ptr++ = ':';
> -     ptr = mem2hex((char *)&regs->reg29, ptr, sizeof(long), 0);
> -     *ptr++ = ';';
> -
> -     *ptr++ = 0;
> -     putpacket(output_buffer);       /* send it off... */
> -
> -     /*
> -      * Wait for input from remote GDB
> -      */
> -     while (1) {
> -             output_buffer[0] = 0;
> -             getpacket(input_buffer);
> -
> -             switch (input_buffer[0])
> -             {
> -             case '?':
> -                     output_buffer[0] = 'S';
> -                     output_buffer[1] = hexchars[sigval >> 4];
> -                     output_buffer[2] = hexchars[sigval & 0xf];
> -                     output_buffer[3] = 0;
> -                     break;
> -
> -             /*
> -              * Detach debugger; let CPU run
> -              */
> -             case 'D':
> -                     putpacket(output_buffer);
> -                     goto finish_kgdb;
> -                     break;
> -
> -             case 'd':
> -                     /* toggle debug flag */
> -                     break;
> -
> -             /*
> -              * Return the value of the CPU registers
> -              */
> -             case 'g':
> -                     ptr = output_buffer;
> -                     ptr = mem2hex((char *)&regs->reg0, ptr, 
> 32*sizeof(long), 0); /* r0...r31 */
> -                     ptr = mem2hex((char *)&regs->cp0_status, ptr, 
> 6*sizeof(long), 0); /* cp0 */
> -                     ptr = mem2hex((char *)&regs->fpr0, ptr, 
> 32*sizeof(long), 0); /* f0...31 */
> -                     ptr = mem2hex((char *)&regs->cp1_fsr, ptr, 
> 2*sizeof(long), 0); /* cp1 */
> -                     ptr = mem2hex((char *)&regs->frame_ptr, ptr, 
> 2*sizeof(long), 0); /* frp */
> -                     ptr = mem2hex((char *)&regs->cp0_index, ptr, 
> 16*sizeof(long), 0); /* cp0 */
> -                     break;
> -
> -             /*
> -              * set the value of the CPU registers - return OK
> -              */
> -             case 'G':
> -             {
> -                     ptr = &input_buffer[1];
> -                     hex2mem(ptr, (char *)&regs->reg0, 32*sizeof(long), 0, 
> 0);
> -                     ptr += 32*(2*sizeof(long));
> -                     hex2mem(ptr, (char *)&regs->cp0_status, 6*sizeof(long), 
> 0, 0);
> -                     ptr += 6*(2*sizeof(long));
> -                     hex2mem(ptr, (char *)&regs->fpr0, 32*sizeof(long), 0, 
> 0);
> -                     ptr += 32*(2*sizeof(long));
> -                     hex2mem(ptr, (char *)&regs->cp1_fsr, 2*sizeof(long), 0, 
> 0);
> -                     ptr += 2*(2*sizeof(long));
> -                     hex2mem(ptr, (char *)&regs->frame_ptr, 2*sizeof(long), 
> 0, 0);
> -                     ptr += 2*(2*sizeof(long));
> -                     hex2mem(ptr, (char *)&regs->cp0_index, 16*sizeof(long), 
> 0, 0);
> -                     strcpy(output_buffer,"OK");
> -              }
> -             break;
> -
> -             /*
> -              * mAA..AA,LLLL  Read LLLL bytes at address AA..AA
> -              */
> -             case 'm':
> -                     ptr = &input_buffer[1];
> -
> -                     if (hexToLong(&ptr, &addr)
> -                             && *ptr++ == ','
> -                             && hexToInt(&ptr, &length)) {
> -                             if (mem2hex((char *)addr, output_buffer, 
> length, 1))
> -                                     break;
> -                             strcpy (output_buffer, "E03");
> -                     } else
> -                             strcpy(output_buffer,"E01");
> -                     break;
> -
> -             /*
> -              * XAA..AA,LLLL: Write LLLL escaped binary bytes at address 
> AA.AA
> -              */
> -             case 'X':
> -                     bflag = 1;
> -                     /* fall through */
> -
> -             /*
> -              * MAA..AA,LLLL: Write LLLL bytes at address AA.AA return OK
> -              */
> -             case 'M':
> -                     ptr = &input_buffer[1];
> -
> -                     if (hexToLong(&ptr, &addr)
> -                             && *ptr++ == ','
> -                             && hexToInt(&ptr, &length)
> -                             && *ptr++ == ':') {
> -                             if (hex2mem(ptr, (char *)addr, length, bflag, 
> 1))
> -                                     strcpy(output_buffer, "OK");
> -                             else
> -                                     strcpy(output_buffer, "E03");
> -                     }
> -                     else
> -                             strcpy(output_buffer, "E02");
> -                     break;
> -
> -             /*
> -              * cAA..AA    Continue at address AA..AA(optional)
> -              */
> -             case 'c':
> -                     /* try to read optional parameter, pc unchanged if no 
> parm */
> -
> -                     ptr = &input_buffer[1];
> -                     if (hexToLong(&ptr, &addr))
> -                             regs->cp0_epc = addr;
> -       
> -                     goto exit_kgdb_exception;
> -                     break;
> -
> -             /*
> -              * kill the program; let us try to restart the machine
> -              * Reset the whole machine.
> -              */
> -             case 'k':
> -             case 'r':
> -                     machine_restart("kgdb restarts machine");
> -                     break;
> -
> -             /*
> -              * Step to next instruction
> -              */
> -             case 's':
> -                     /*
> -                      * There is no single step insn in the MIPS ISA, so we
> -                      * use breakpoints and continue, instead.
> -                      */
> -                     single_step(regs);
> -                     goto exit_kgdb_exception;
> -                     /* NOTREACHED */
> -                     break;
> -
> -             /*
> -              * Set baud rate (bBB)
> -              * FIXME: Needs to be written
> -              */
> -             case 'b':
> -             {
> -#if 0
> -                     int baudrate;
> -                     extern void set_timer_3();
> -
> -                     ptr = &input_buffer[1];
> -                     if (!hexToInt(&ptr, &baudrate))
> -                     {
> -                             strcpy(output_buffer,"B01");
> -                             break;
> -                     }
> -
> -                     /* Convert baud rate to uart clock divider */
> -
> -                     switch (baudrate)
> -                     {
> -                             case 38400:
> -                                     baudrate = 16;
> -                                     break;
> -                             case 19200:
> -                                     baudrate = 33;
> -                                     break;
> -                             case 9600:
> -                                     baudrate = 65;
> -                                     break;
> -                             default:
> -                                     baudrate = 0;
> -                                     strcpy(output_buffer,"B02");
> -                                     goto x1;
> -                     }
> -
> -                     if (baudrate) {
> -                             putpacket("OK");        /* Ack before changing 
> speed */
> -                             set_timer_3(baudrate); /* Set it */
> -                     }
> -#endif
> -             }
> -             break;
> -
> -             }                       /* switch */
> -
> -             /*
> -              * reply to the request
> -              */
> -
> -             putpacket(output_buffer);
> -
> -     } /* while */
> -
> -     return;
> -
> -finish_kgdb:
> -     restore_debug_traps();
> -
> -exit_kgdb_exception:
> -     /* release locks so other CPUs can go */
> -     for (i = num_online_cpus()-1; i >= 0; i--)
> -             spin_unlock(&kgdb_cpulock[i]);
> -     spin_unlock(&kgdb_lock);
> -
> -     __flush_cache_all();
> -     return;
> -}
> -
> -/*
> - * This function will generate a breakpoint exception.  It is used at the
> - * beginning of a program to sync up with a debugger and can be used
> - * otherwise as a quick means to stop program execution and "break" into
> - * the debugger.
> - */
> -void breakpoint(void)
> -{
> -     if (!initialized)
> -             return;
> -
> -     __asm__ __volatile__(
> -                     ".globl breakinst\n\t" 
> -                     ".set\tnoreorder\n\t"
> -                     "nop\n"
> -                     "breakinst:\tbreak\n\t"
> -                     "nop\n\t"
> -                     ".set\treorder"
> -                     );
> -}
> -
> -/* Nothing but the break; don't pollute any registers */
> -void async_breakpoint(void)
> -{
> -     __asm__ __volatile__(
> -                     ".globl async_breakinst\n\t" 
> -                     ".set\tnoreorder\n\t"
> -                     "nop\n"
> -                     "async_breakinst:\tbreak\n\t"
> -                     "nop\n\t"
> -                     ".set\treorder"
> -                     );
> -}
> -
> -void adel(void)
> -{
> -     __asm__ __volatile__(
> -                     ".globl\tadel\n\t"
> -                     "lui\t$8,0x8000\n\t"
> -                     "lw\t$9,1($8)\n\t"
> -                     );
> -}
> -
> -/*
> - * malloc is needed by gdb client in "call func()", even a private one
> - * will make gdb happy
> - */
> -static void *malloc(size_t size)
> -{
> -     return kmalloc(size, GFP_ATOMIC);
> -}
> -
> -static void free(void *where)
> -{
> -     kfree(where);
> -}
> -
> -#ifdef CONFIG_GDB_CONSOLE
> -
> -void gdb_putsn(const char *str, int l)
> -{
> -     char outbuf[18];
> -
> -     if (!kgdb_started)
> -             return;
> -
> -     outbuf[0]='O';
> -
> -     while(l) {
> -             int i = (l>8)?8:l;
> -             mem2hex((char *)str, &outbuf[1], i, 0);
> -             outbuf[(i*2)+1]=0;
> -             putpacket(outbuf);
> -             str += i;
> -             l -= i;
> -     }
> -}
> -
> -static void gdb_console_write(struct console *con, const char *s, unsigned n)
> -{
> -     gdb_putsn(s, n);
> -}
> -
> -static struct console gdb_console = {
> -     .name   = "gdb",
> -     .write  = gdb_console_write,
> -     .flags  = CON_PRINTBUFFER,
> -     .index  = -1
> -};
> -
> -static int __init register_gdb_console(void)
> -{
> -     register_console(&gdb_console);
> -
> -     return 0;
> -}
> -
> -console_initcall(register_gdb_console);
> -
> -#endif
> diff -puN arch/mips/kernel/irq.c~mips-lite arch/mips/kernel/irq.c
> --- linux-2.6.13-rc3/arch/mips/kernel/irq.c~mips-lite 2005-07-29 
> 11:55:31.000000000 -0700
> +++ linux-2.6.13-rc3-trini/arch/mips/kernel/irq.c     2005-07-29 
> 11:55:31.000000000 -0700
> @@ -26,6 +26,10 @@
>  #include <asm/atomic.h>
>  #include <asm/system.h>
>  #include <asm/uaccess.h>
> +#include <asm/kgdb.h>
> +
> +/* Keep track of if we've done certain initialization already or not. */
> +int kgdb_early_setup;
>  
>  /*
>   * 'what should we do if we get a hw irq event on an illegal vector'.
> @@ -103,23 +107,13 @@ skip:
>       return 0;
>  }
>  
> -#ifdef CONFIG_KGDB
> -extern void breakpoint(void);
> -extern void set_debug_traps(void);
> -
> -static int kgdb_flag = 1;
> -static int __init nokgdb(char *str)
> -{
> -     kgdb_flag = 0;
> -     return 1;
> -}
> -__setup("nokgdb", nokgdb);
> -#endif
> -
>  void __init init_IRQ(void)
>  {
>       int i;
>  
> +     if (kgdb_early_setup)
> +             return;
> +
>       for (i = 0; i < NR_IRQS; i++) {
>               irq_desc[i].status  = IRQ_DISABLED;
>               irq_desc[i].action  = NULL;
> @@ -129,12 +123,12 @@ void __init init_IRQ(void)
>       }
>  
>       arch_init_irq();
> -
>  #ifdef CONFIG_KGDB
> -     if (kgdb_flag) {
> -             printk("Wait for gdb client connection ...\n");
> -             set_debug_traps();
> -             breakpoint();
> -     }
> +     /*
> +      * We have been called before kgdb_arch_init(). Hence,
> +      * we dont want the traps to be reinitialized
> +      */
> +     if (kgdb_early_setup == 0)
> +             kgdb_early_setup = 1;
>  #endif
>  }
> diff -puN /dev/null arch/mips/kernel/kgdb.c
> --- /dev/null 2005-07-25 10:57:32.312383000 -0700
> +++ linux-2.6.13-rc3-trini/arch/mips/kernel/kgdb.c    2005-07-29 
> 11:55:31.000000000 -0700
> @@ -0,0 +1,292 @@
> +/*
> + * arch/mips/kernel/kgdb.c
> + *
> + *  Originally written by Glenn Engel, Lake Stevens Instrument Division
> + *
> + *  Contributed by HP Systems
> + *
> + *  Modified for SPARC by Stu Grossman, Cygnus Support.
> + *
> + *  Modified for Linux/MIPS (and MIPS in general) by Andreas Busse
> + *  Send complaints, suggestions etc. to <andy@waldorf-gmbh.de>
> + *
> + *  Copyright (C) 1995 Andreas Busse
> + *
> + *  Copyright (C) 2003 MontaVista Software Inc.
> + *  Author: Jun Sun, jsun@mvista.com or jsun@junsun.net
> + *
> + *  Copyright (C) 2004-2005 MontaVista Software Inc.
> + *  Author: Manish Lachwani, mlachwani@mvista.com or manish@koffee-break.com
> + *
> + *  This file is licensed under the terms of the GNU General Public License
> + *  version 2. This program is licensed "as is" without any warranty of any
> + *  kind, whether express or implied.
> + */
> +
> +#include <linux/string.h>
> +#include <linux/kernel.h>
> +#include <linux/sched.h>
> +#include <linux/smp.h>
> +#include <linux/spinlock.h>
> +#include <linux/delay.h>
> +#include <asm/system.h>
> +#include <asm/ptrace.h>              /* for linux pt_regs struct */
> +#include <linux/kgdb.h>
> +#include <linux/init.h>
> +#include <asm/inst.h>
> +#include <asm/gdb-stub.h>
> +#include <asm/cacheflush.h>
> +#include <asm/kdebug.h>
> +
> +static struct hard_trap_info {
> +     unsigned char tt;       /* Trap type code for MIPS R3xxx and R4xxx */
> +     unsigned char signo;    /* Signal that we map this trap into */
> +} hard_trap_info[] = {
> +     { 6, SIGBUS },          /* instruction bus error */
> +     { 7, SIGBUS },          /* data bus error */
> +     { 9, SIGTRAP },         /* break */
> +/*   { 11, SIGILL }, */      /* CPU unusable */
> +     { 12, SIGFPE },         /* overflow */
> +     { 13, SIGTRAP },        /* trap */
> +     { 14, SIGSEGV },        /* virtual instruction cache coherency */
> +     { 15, SIGFPE },         /* floating point exception */
> +     { 23, SIGSEGV },        /* watch */
> +     { 31, SIGSEGV },        /* virtual data cache coherency */
> +     { 0, 0}                 /* Must be last */
> +};
> +
> +/* Save the normal trap handlers for user-mode traps. */
> +void *saved_vectors[32];
> +
> +extern void trap_low(void);
> +extern void breakinst(void);
> +extern void init_IRQ(void);
> +
> +void kgdb_call_nmi_hook(void *ignored)
> +{
> +     kgdb_nmihook(smp_processor_id(), (void *)0);
> +}
> +
> +void kgdb_roundup_cpus(unsigned long flags)
> +{
> +     local_irq_restore(flags);
> +     smp_call_function(kgdb_call_nmi_hook, 0, 0, 0);
> +     local_irq_save(flags);
> +}
> +
> +static int compute_signal(int tt)
> +{
> +     struct hard_trap_info *ht;
> +
> +     for (ht = hard_trap_info; ht->tt && ht->signo; ht++)
> +             if (ht->tt == tt)
> +                     return ht->signo;
> +
> +     return SIGHUP;          /* default for things we don't know about */
> +}
> +
> +/*
> + * Set up exception handlers for tracing and breakpoints
> + */
> +void handle_exception(struct pt_regs *regs)
> +{
> +     int trap = (regs->cp0_cause & 0x7c) >> 2;
> +
> +     if (atomic_read(&debugger_active))
> +             kgdb_nmihook(smp_processor_id(), regs);
> +
> +     if (atomic_read(&kgdb_setting_breakpoint))
> +             if ((trap == 9) && (regs->cp0_epc == (unsigned long)breakinst))
> +                     regs->cp0_epc += 4;
> +
> +     kgdb_handle_exception(0, compute_signal(trap), 0, regs);
> +
> +     /* In SMP mode, __flush_cache_all does IPI */
> +     __flush_cache_all();
> +}
> +
> +void set_debug_traps(void)
> +{
> +     struct hard_trap_info *ht;
> +     unsigned long flags;
> +
> +     local_irq_save(flags);
> +
> +     for (ht = hard_trap_info; ht->tt && ht->signo; ht++)
> +             saved_vectors[ht->tt] = set_except_vector(ht->tt, trap_low);
> +
> +     local_irq_restore(flags);
> +}
> +
> +#if 0
> +/* This should be called before we exit kgdb_handle_exception() I believe.
> + * -- Tom
> + */
> +void restore_debug_traps(void)
> +{
> +     struct hard_trap_info *ht;
> +     unsigned long flags;
> +
> +     local_irq_save(flags);
> +     for (ht = hard_trap_info; ht->tt && ht->signo; ht++)
> +             set_except_vector(ht->tt, saved_vectors[ht->tt]);
> +     local_irq_restore(flags);
> +}
> +#endif
> +
> +void regs_to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *regs)
> +{
> +     int reg = 0;
> +     unsigned long *ptr = gdb_regs;
> +
> +     for (reg = 0; reg < 32; reg++)
> +             *(ptr++) = regs->regs[reg];
> +
> +     *(ptr++) = regs->cp0_status;
> +     *(ptr++) = regs->lo;
> +     *(ptr++) = regs->hi;
> +     *(ptr++) = regs->cp0_badvaddr;
> +     *(ptr++) = regs->cp0_cause;
> +     *(ptr++) = regs->cp0_epc;
> +
> +     return;
> +}
> +
> +void gdb_regs_to_regs(unsigned long *gdb_regs, struct pt_regs *regs)
> +{
> +     int reg = 0;
> +     unsigned long *ptr = gdb_regs;
> +
> +     for (reg = 0; reg < 32; reg++)
> +             regs->regs[reg] = *(ptr++);
> +
> +     regs->cp0_status = *(ptr++);
> +     regs->lo = *(ptr++);
> +     regs->hi = *(ptr++);
> +     regs->cp0_badvaddr = *(ptr++);
> +     regs->cp0_cause = *(ptr++);
> +     regs->cp0_epc = *(ptr++);
> +
> +     return;
> +}
> +
> +/*
> + * Similar to regs_to_gdb_regs() except that process is sleeping and so
> + * we may not be able to get all the info.
> + */
> +void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct 
> *p)
> +{
> +     int reg = 0;
> +     struct thread_info *ti = p->thread_info;
> +     unsigned long ksp = (unsigned long)ti + THREAD_SIZE - 32;
> +     struct pt_regs *regs = (struct pt_regs *)ksp - 1;
> +     unsigned long *ptr = gdb_regs;
> +
> +     for (reg = 0; reg < 16; reg++)
> +             *(ptr++) = regs->regs[reg];
> +
> +     /* S0 - S7 */
> +     for (reg = 16; reg < 24; reg++)
> +             *(ptr++) = regs->regs[reg];
> +
> +     for (reg = 24; reg < 28; reg++)
> +             *(ptr++) = 0;
> +
> +     /* GP, SP, FP, RA */
> +     for (reg = 28; reg < 32; reg++)
> +             *(ptr++) = regs->regs[reg];
> +
> +     *(ptr++) = regs->cp0_status;
> +     *(ptr++) = regs->lo;
> +     *(ptr++) = regs->hi;
> +     *(ptr++) = regs->cp0_badvaddr;
> +     *(ptr++) = regs->cp0_cause;
> +     *(ptr++) = regs->cp0_epc;
> +
> +     return;
> +}
> +
> +/*
> + * Calls linux_debug_hook before the kernel dies. If KGDB is enabled,
> + * then try to fall into the debugger
> + */
> +static int kgdb_mips_notify(struct notifier_block *self, unsigned long cmd,
> +                         void *ptr)
> +{
> +     struct die_args *args = (struct die_args *)ptr;
> +     struct pt_regs *regs = args->regs;
> +     int trap = (regs->cp0_cause & 0x7c) >> 2;
> +
> +     /* See if KGDB is interested. */
> +     if (user_mode(regs))
> +             /* Userpace events, ignore. */
> +             return NOTIFY_DONE;
> +
> +     kgdb_handle_exception(trap, compute_signal(trap), 0, regs);
> +     return NOTIFY_OK;
> +}
> +
> +static struct notifier_block kgdb_notifier = {
> +     .notifier_call = kgdb_mips_notify,
> +};
> +
> +/*
> + * Handle the 's' and 'c' commands
> + */
> +int kgdb_arch_handle_exception(int vector, int signo, int err_code,
> +                            char *remcom_in_buffer, char *remcom_out_buffer,
> +                            struct pt_regs *regs)
> +{
> +     char *ptr;
> +     unsigned long address;
> +     int cpu = smp_processor_id();
> +
> +     switch (remcom_in_buffer[0]) {
> +     case 's':
> +     case 'c':
> +             /* handle the optional parameter */
> +             ptr = &remcom_in_buffer[1];
> +             if (kgdb_hex2long(&ptr, &address))
> +                     regs->cp0_epc = address;
> +
> +             atomic_set(&cpu_doing_single_step, -1);
> +             if (remcom_in_buffer[0] == 's')
> +                     if (kgdb_contthread)
> +                             atomic_set(&cpu_doing_single_step, cpu);
> +
> +             return 0;
> +     }
> +
> +     return -1;
> +}
> +
> +struct kgdb_arch arch_kgdb_ops = {
> +#ifdef CONFIG_CPU_LITTLE_ENDIAN
> +     .gdb_bpt_instr = {0xd},
> +#else
> +     .gdb_bpt_instr = {0x00, 0x00, 0x00, 0x0d},
> +#endif
> +};
> +
> +/*
> + * We use kgdb_early_setup so that functions we need to call now don't
> + * cause trouble when called again later.
> + */
> +int kgdb_arch_init(void)
> +{
> +     /* Board-specifics. */
> +     /* Force some calls to happen earlier. */
> +     if (kgdb_early_setup == 0) {
> +             trap_init();
> +             init_IRQ();
> +             kgdb_early_setup = 1;
> +     }
> +
> +     /* Set our traps. */
> +     /* This needs to be done more finely grained again, paired in
> +      * a before/after in kgdb_handle_exception(...) -- Tom */
> +     set_debug_traps();
> +     notifier_chain_register(&mips_die_chain, &kgdb_notifier);
> +
> +     return 0;
> +}
> diff -puN /dev/null arch/mips/kernel/kgdb_handler.S
> --- /dev/null 2005-07-25 10:57:32.312383000 -0700
> +++ linux-2.6.13-rc3-trini/arch/mips/kernel/kgdb_handler.S    2005-07-29 
> 11:55:31.000000000 -0700
> @@ -0,0 +1,58 @@
> +/*
> + * arch/mips/kernel/kgdb_handler.S
> + *
> + * Copyright (C) 2004 MontaVista Software Inc.
> + * Author: Manish Lachwani, mlachwani@mvista.com or manish@koffee-break.com
> + *
> + * This file is licensed under the terms of the GNU General Public
> + * version 2. This program is licensed "as is" without any warranty of any
> + * kind, whether express or implied.
> + */
> +
> +/*
> + * Trap Handler for the new KGDB framework. The main KGDB handler is
> + * handle_exception that will be called from here
> + *
> + */
> +
> +#include <linux/config.h>
> +#include <linux/sys.h>
> +
> +#include <asm/asm.h>
> +#include <asm/errno.h>
> +#include <asm/mipsregs.h>
> +#include <asm/regdef.h>
> +#include <asm/stackframe.h>
> +
> +     .align  5
> +     NESTED(trap_low, PT_SIZE, sp)
> +             .set    noat
> +             .set    noreorder
> +             SAVE_ALL
> +             /*
> +              * Check for privileged instructions in user mode. For
> +              * this, check the cu0 bit in the CPU status register.
> +              */
> +             mfc0    k0, CP0_STATUS
> +             sll     k0, 3
> +             bltz    k0, 1f
> +             move    k1, sp
> +
> +             /*
> +              * GDB userland from within KGDB. If a user mode address
> +              * then jump to the saved exception handler
> +              */
> +             lui     k1, %hi(saved_vectors)
> +             mfc0    k0, CP0_CAUSE
> +             andi    k0, k0, 0x7c
> +             add     k1, k1, k0
> +             lw      k0, %lo(saved_vectors)(k1)
> +             jr      k0
> +             nop
> +1:
> +             .set    at
> +             .set    reorder
> +             move    a0, sp
> +             jal     handle_exception
> +             j       ret_from_exception
> +     END(trap_low)
> diff -puN /dev/null arch/mips/kernel/kgdb-jmp.c
> --- /dev/null 2005-07-25 10:57:32.312383000 -0700
> +++ linux-2.6.13-rc3-trini/arch/mips/kernel/kgdb-jmp.c        2005-07-29 
> 11:55:31.000000000 -0700
> @@ -0,0 +1,62 @@
> +/*
> + * arch/mips/kernel/kgdb-jmp.c
> + *
> + * Save and restore system registers so that within a limited frame we
> + * may have a fault and "jump back" to a known safe location.
> + *
> + * Author: Tom Rini <trini@kernel.crashing.org>
> + *
> + * Cribbed from glibc, which carries the following:
> + * Copyright (C) 1996, 1997, 2000, 2002, 2003 Free Software Foundation, Inc.
> + * Copyright (C) 2005 by MontaVista Software.
> + *
> + * This file is licensed under the terms of the GNU General Public License
> + * version 2. This program as licensed "as is" without any warranty of
> + * any kind, whether express or implied.
> + */
> +
> +#include <linux/kgdb.h>
> +#include <asm/interrupt.h>
> +
> +int kgdb_fault_setjmp_aux(unsigned long *curr_context, int sp, int fp)
> +{
> +     __asm__ __volatile__("sw $gp, %0" : : "m" (curr_context[0]));
> +     __asm__ __volatile__("sw $16, %0" : : "m" (curr_context[1]));
> +     __asm__ __volatile__("sw $17, %0" : : "m" (curr_context[2]));
> +     __asm__ __volatile__("sw $18, %0" : : "m" (curr_context[3]));
> +     __asm__ __volatile__("sw $19, %0" : : "m" (curr_context[4]));
> +     __asm__ __volatile__("sw $20, %0" : : "m" (curr_context[5]));
> +     __asm__ __volatile__("sw $21, %0" : : "m" (curr_context[6]));
> +     __asm__ __volatile__("sw $22, %0" : : "m" (curr_context[7]));
> +     __asm__ __volatile__("sw $23, %0" : : "m" (curr_context[8]));
> +     __asm__ __volatile__("sw $31, %0" : : "m" (curr_context[9]));
> +     curr_context[10] = (long *)sp;
> +     curr_context[11] = (long *)fp;
> +
> +     return 0;
> +}
> +
> +void kgdb_fault_longjmp(unsigned long *curr_context)
> +{
> +     unsigned long sp_val, fp_val;
> +
> +     __asm__ __volatile__("lw $gp, %0" : : "m" (curr_context[0]));
> +     __asm__ __volatile__("lw $16, %0" : : "m" (curr_context[1]));
> +     __asm__ __volatile__("lw $17, %0" : : "m" (curr_context[2]));
> +     __asm__ __volatile__("lw $18, %0" : : "m" (curr_context[3]));
> +     __asm__ __volatile__("lw $19, %0" : : "m" (curr_context[4]));
> +     __asm__ __volatile__("lw $20, %0" : : "m" (curr_context[5]));
> +     __asm__ __volatile__("lw $21, %0" : : "m" (curr_context[6]));
> +     __asm__ __volatile__("lw $22, %0" : : "m" (curr_context[7]));
> +     __asm__ __volatile__("lw $23, %0" : : "m" (curr_context[8]));
> +     __asm__ __volatile__("lw $25, %0" : : "m" (curr_context[9]));
> +     sp_val = curr_context[10];
> +     fp_val = curr_context[11];
> +     __asm__ __volatile__("lw $29, %0\n\t"
> +                           "lw $30, %1\n\t" : : "m" (sp_val), "m" (fp_val));
> +
> +     __asm__ __volatile__("li $2, 1");
> +     __asm__ __volatile__("jr $25");
> +
> +     for (;;);
> +}
> diff -puN /dev/null arch/mips/kernel/kgdb-setjmp.S
> --- /dev/null 2005-07-25 10:57:32.312383000 -0700
> +++ linux-2.6.13-rc3-trini/arch/mips/kernel/kgdb-setjmp.S     2005-07-29 
> 11:55:31.000000000 -0700
> @@ -0,0 +1,23 @@
> +/*
> + * arch/mips/kernel/kgdb-jmp.c
> + *
> + * Save and restore system registers so that within a limited frame we
> + * may have a fault and "jump back" to a known safe location.
> + *
> + * Copyright (C) 2005 by MontaVista Software.
> + *
> + * This file is licensed under the terms of the GNU General Public License
> + * version 2. This program as licensed "as is" without any warranty of
> + * any kind, whether express or implied.
> + */
> +
> +#include <asm/asm.h>
> +#include <asm/mipsregs.h>
> +#include <asm/regdef.h>
> +#include <asm/stackframe.h>
> +
> +ENTRY (kgdb_fault_setjmp)
> +     move    a1, sp
> +     move    a2, fp
> +     j       kgdb_fault_setjmp_aux
> +     .end    kgdb_fault_setjmp
> diff -puN arch/mips/kernel/Makefile~mips-lite arch/mips/kernel/Makefile
> --- linux-2.6.13-rc3/arch/mips/kernel/Makefile~mips-lite      2005-07-29 
> 11:55:31.000000000 -0700
> +++ linux-2.6.13-rc3-trini/arch/mips/kernel/Makefile  2005-07-29 
> 11:55:31.000000000 -0700
> @@ -52,7 +52,8 @@ obj-$(CONFIG_MIPS32_COMPAT) += ioctl32.o
>  obj-$(CONFIG_MIPS32_N32)     += binfmt_elfn32.o scall64-n32.o signal_n32.o
>  obj-$(CONFIG_MIPS32_O32)     += binfmt_elfo32.o scall64-o32.o ptrace32.o
>  
> -obj-$(CONFIG_KGDB)           += gdb-low.o gdb-stub.o
> +obj-$(CONFIG_KGDB)           += kgdb_handler.o kgdb.o kgdb-jmp.o     \
> +                                     kgdb-setjmp.o
>  obj-$(CONFIG_PROC_FS)                += proc.o
>  
>  obj-$(CONFIG_MIPS64)         += cpu-bugs64.o
> diff -puN arch/mips/kernel/traps.c~mips-lite arch/mips/kernel/traps.c
> --- linux-2.6.13-rc3/arch/mips/kernel/traps.c~mips-lite       2005-07-29 
> 11:55:31.000000000 -0700
> +++ linux-2.6.13-rc3-trini/arch/mips/kernel/traps.c   2005-07-29 
> 11:55:31.000000000 -0700
> @@ -10,6 +10,8 @@
>   * Kevin D. Kissell, kevink@mips.com and Carsten Langgaard, carstenl@mips.com
>   * Copyright (C) 2000, 01 MIPS Technologies, Inc.
>   * Copyright (C) 2002, 2003, 2004  Maciej W. Rozycki
> + *
> + * KGDB specific changes - Manish Lachwani (mlachwani@mvista.com)
>   */
>  #include <linux/config.h>
>  #include <linux/init.h>
> @@ -20,6 +22,7 @@
>  #include <linux/smp_lock.h>
>  #include <linux/spinlock.h>
>  #include <linux/kallsyms.h>
> +#include <linux/kgdb.h>
>  
>  #include <asm/bootinfo.h>
>  #include <asm/branch.h>
> @@ -37,6 +40,7 @@
>  #include <asm/mmu_context.h>
>  #include <asm/watch.h>
>  #include <asm/types.h>
> +#include <asm/kdebug.h>
>  
>  extern asmlinkage void handle_tlbm(void);
>  extern asmlinkage void handle_tlbl(void);
> @@ -69,6 +73,21 @@ int (*board_be_handler)(struct pt_regs *
>   */
>  #define MODULE_RANGE (8*1024*1024)
>  
> +struct notifier_block *mips_die_chain;
> +static spinlock_t die_notifier_lock = SPIN_LOCK_UNLOCKED;
> +
> +int register_die_notifier(struct notifier_block *nb)
> +{
> +     int err = 0;
> +     unsigned long flags;
> +
> +     spin_lock_irqsave(&die_notifier_lock, flags);
> +     err = notifier_chain_register(&mips_die_chain, nb);
> +     spin_unlock_irqrestore(&die_notifier_lock, flags);
> +
> +     return err;
> +}
> +
>  /*
>   * This routine abuses get_user()/put_user() to reference pointers
>   * with at least a bit of error checking ...
> @@ -271,8 +290,10 @@ NORET_TYPE void __die(const char * str, 
>  void __die_if_kernel(const char * str, struct pt_regs * regs,
>                    const char * file, const char * func, unsigned long line)
>  {
> -     if (!user_mode(regs))
> +     if (!user_mode(regs)) {
> +             notify_die(DIE_TRAP, (char *)str, regs, 0);
>               __die(str, regs, file, func, line);
> +     }
>  }
>  
>  extern const struct exception_table_entry __start___dbe_table[];
> @@ -958,6 +979,9 @@ void __init trap_init(void)
>       extern char except_vec4;
>       unsigned long i;
>  
> +     if (kgdb_early_setup)
> +             return; /* Already done */
> +
>       per_cpu_trap_init();
>  
>       /*
> diff -puN arch/mips/mips-boards/generic/init.c~mips-lite 
> arch/mips/mips-boards/generic/init.c
> --- linux-2.6.13-rc3/arch/mips/mips-boards/generic/init.c~mips-lite   
> 2005-07-29 11:55:31.000000000 -0700
> +++ linux-2.6.13-rc3-trini/arch/mips/mips-boards/generic/init.c       
> 2005-07-29 11:55:31.000000000 -0700
> @@ -35,15 +35,6 @@
>  #include <asm/mips-boards/malta.h>
>  #endif
>  
> -#ifdef CONFIG_KGDB
> -extern int rs_kgdb_hook(int, int);
> -extern int rs_putDebugChar(char);
> -extern char rs_getDebugChar(void);
> -extern int saa9730_kgdb_hook(int);
> -extern int saa9730_putDebugChar(char);
> -extern char saa9730_getDebugChar(void);
> -#endif
> -
>  int prom_argc;
>  int *_prom_argv, *_prom_envp;
>  
> @@ -170,59 +161,6 @@ static void __init console_config(void)
>  }
>  #endif
>  
> -#ifdef CONFIG_KGDB
> -void __init kgdb_config (void)
> -{
> -     extern int (*generic_putDebugChar)(char);
> -     extern char (*generic_getDebugChar)(void);
> -     char *argptr;
> -     int line, speed;
> -
> -     argptr = prom_getcmdline();
> -     if ((argptr = strstr(argptr, "kgdb=ttyS")) != NULL) {
> -             argptr += strlen("kgdb=ttyS");
> -             if (*argptr != '0' && *argptr != '1')
> -                     printk("KGDB: Unknown serial line /dev/ttyS%c, "
> -                            "falling back to /dev/ttyS1\n", *argptr);
> -             line = *argptr == '0' ? 0 : 1;
> -             printk("KGDB: Using serial line /dev/ttyS%d for session\n", 
> line);
> -
> -             speed = 0;
> -             if (*++argptr == ',')
> -             {
> -                     int c;
> -                     while ((c = *++argptr) && ('0' <= c && c <= '9'))
> -                             speed = speed * 10 + c - '0';
> -             }
> -#ifdef CONFIG_MIPS_ATLAS
> -             if (line == 1) {
> -                     speed = saa9730_kgdb_hook(speed);
> -                     generic_putDebugChar = saa9730_putDebugChar;
> -                     generic_getDebugChar = saa9730_getDebugChar;
> -             }
> -             else 
> -#endif
> -             {
> -                     speed = rs_kgdb_hook(line, speed);
> -                     generic_putDebugChar = rs_putDebugChar;
> -                     generic_getDebugChar = rs_getDebugChar;
> -             }
> -
> -             prom_printf("KGDB: Using serial line /dev/ttyS%d at %d for 
> session, "
> -                         "please connect your debugger\n", line ? 1 : 0, 
> speed);
> -
> -             {
> -                     char *s;
> -                     for (s = "Please connect GDB to this port\r\n"; *s; )
> -                             generic_putDebugChar (*s++);
> -             }
> -
> -             kgdb_enabled = 1;
> -             /* Breakpoint is invoked after interrupts are initialised */
> -     }
> -}
> -#endif
> -
>  void __init prom_init(void)
>  {
>       prom_argc = fw_arg0;
> diff -puN arch/mips/mips-boards/generic/Makefile~mips-lite 
> arch/mips/mips-boards/generic/Makefile
> --- linux-2.6.13-rc3/arch/mips/mips-boards/generic/Makefile~mips-lite 
> 2005-07-29 11:55:31.000000000 -0700
> +++ linux-2.6.13-rc3-trini/arch/mips/mips-boards/generic/Makefile     
> 2005-07-29 11:55:31.000000000 -0700
> @@ -21,6 +21,5 @@
>  obj-y                                := mipsIRQ.o reset.o display.o init.o 
> memory.o \
>                                  printf.o cmdline.o time.o
>  obj-$(CONFIG_PCI)            += pci.o
> -obj-$(CONFIG_KGDB)           += gdb_hook.o
>  
>  EXTRA_AFLAGS := $(CFLAGS)
> diff -puN arch/mips/mips-boards/malta/malta_setup.c~mips-lite 
> arch/mips/mips-boards/malta/malta_setup.c
> --- linux-2.6.13-rc3/arch/mips/mips-boards/malta/malta_setup.c~mips-lite      
> 2005-07-29 11:55:31.000000000 -0700
> +++ linux-2.6.13-rc3-trini/arch/mips/mips-boards/malta/malta_setup.c  
> 2005-07-29 11:55:31.000000000 -0700
> @@ -48,10 +48,6 @@ extern void mips_time_init(void);
>  extern void mips_timer_setup(struct irqaction *irq);
>  extern unsigned long mips_rtc_get_time(void);
>  
> -#ifdef CONFIG_KGDB
> -extern void kgdb_config(void);
> -#endif
> -
>  struct resource standard_io_resources[] = {
>       { "dma1", 0x00, 0x1f, IORESOURCE_BUSY },
>       { "timer", 0x40, 0x5f, IORESOURCE_BUSY },
> @@ -124,10 +120,6 @@ static int __init malta_setup(void)
>        */
>       enable_dma(4);
>  
> -#ifdef CONFIG_KGDB
> -     kgdb_config ();
> -#endif
> -
>       if ((mips_revision_corid == MIPS_REVISION_CORID_BONITO64) ||
>           (mips_revision_corid == MIPS_REVISION_CORID_CORE_20K) ||
>           (mips_revision_corid == MIPS_REVISION_CORID_CORE_EMUL_BON)) {
> diff -puN arch/mips/mm/extable.c~mips-lite arch/mips/mm/extable.c
> --- linux-2.6.13-rc3/arch/mips/mm/extable.c~mips-lite 2005-07-29 
> 11:55:31.000000000 -0700
> +++ linux-2.6.13-rc3-trini/arch/mips/mm/extable.c     2005-07-29 
> 11:55:31.000000000 -0700
> @@ -3,6 +3,7 @@
>   */
>  #include <linux/module.h>
>  #include <linux/spinlock.h>
> +#include <linux/kgdb.h>
>  #include <asm/branch.h>
>  #include <asm/uaccess.h>
>  
> @@ -16,6 +17,12 @@ int fixup_exception(struct pt_regs *regs
>  
>               return 1;
>       }
> +#ifdef CONFIG_KGDB
> +     if (atomic_read(&debugger_active) && kgdb_may_fault)
> +             /* Restore our previous state. */
> +             kgdb_fault_longjmp(kgdb_fault_jmp_regs);
> +             /* Not reached. */
> +#endif
>  
>       return 0;
>  }
> diff -puN arch/mips/sibyte/cfe/setup.c~mips-lite arch/mips/sibyte/cfe/setup.c
> --- linux-2.6.13-rc3/arch/mips/sibyte/cfe/setup.c~mips-lite   2005-07-29 
> 11:55:31.000000000 -0700
> +++ linux-2.6.13-rc3-trini/arch/mips/sibyte/cfe/setup.c       2005-07-29 
> 11:55:31.000000000 -0700
> @@ -58,10 +58,6 @@ int cfe_cons_handle;
>  extern unsigned long initrd_start, initrd_end;
>  #endif
>  
> -#ifdef CONFIG_KGDB
> -extern int kgdb_port;
> -#endif
> -
>  static void ATTRIB_NORET cfe_linux_exit(void *arg)
>  {
>       int warm = *(int *)arg;
> @@ -242,9 +238,6 @@ void __init prom_init(void)
>       int argc = fw_arg0;
>       char **envp = (char **) fw_arg2;
>       int *prom_vec = (int *) fw_arg3;
> -#ifdef CONFIG_KGDB
> -     char *arg;
> -#endif
>  
>       _machine_restart   = cfe_linux_restart;
>       _machine_halt      = cfe_linux_halt;
> @@ -308,13 +301,6 @@ void __init prom_init(void)
>               }
>       }
>  
> -#ifdef CONFIG_KGDB
> -     if ((arg = strstr(arcs_cmdline,"kgdb=duart")) != NULL)
> -             kgdb_port = (arg[10] == '0') ? 0 : 1;
> -     else
> -             kgdb_port = 1;
> -#endif
> -
>  #ifdef CONFIG_BLK_DEV_INITRD
>       {
>               char *ptr;
> diff -puN arch/mips/sibyte/sb1250/irq.c~mips-lite 
> arch/mips/sibyte/sb1250/irq.c
> --- linux-2.6.13-rc3/arch/mips/sibyte/sb1250/irq.c~mips-lite  2005-07-29 
> 11:55:31.000000000 -0700
> +++ linux-2.6.13-rc3-trini/arch/mips/sibyte/sb1250/irq.c      2005-07-29 
> 11:55:31.000000000 -0700
> @@ -31,6 +31,7 @@
>  #include <asm/system.h>
>  #include <asm/ptrace.h>
>  #include <asm/io.h>
> +#include <asm/kgdb.h>
>  
>  #include <asm/sibyte/sb1250_regs.h>
>  #include <asm/sibyte/sb1250_int.h>
> @@ -60,16 +61,6 @@ static void sb1250_set_affinity(unsigned
>  extern unsigned long ldt_eoi_space;
>  #endif
>  
> -#ifdef CONFIG_KGDB
> -static int kgdb_irq;
> -
> -/* Default to UART1 */
> -int kgdb_port = 1;
> -#ifdef CONFIG_SIBYTE_SB1250_DUART
> -extern char sb1250_duart_present[];
> -#endif
> -#endif
> -
>  static struct hw_interrupt_type sb1250_irq_type = {
>       "SB1250-IMR",
>       startup_sb1250_irq,
> @@ -338,6 +329,11 @@ void __init arch_init_irq(void)
>       unsigned int imask = STATUSF_IP4 | STATUSF_IP3 | STATUSF_IP2 |
>               STATUSF_IP1 | STATUSF_IP0;
>  
> +#ifdef CONFIG_KGDB
> +     if (kgdb_early_setup)
> +             return;
> +#endif
> +
>       /* Default everything to IP2 */
>       for (i = 0; i < SB1250_NR_IRQS; i++) {  /* was I0 */
>               bus_writeq(IMR_IP2_VAL,
> @@ -387,45 +383,4 @@ void __init arch_init_irq(void)
>       /* Enable necessary IPs, disable the rest */
>       change_c0_status(ST0_IM, imask);
>       set_except_vector(0, sb1250_irq_handler);
> -
> -#ifdef CONFIG_KGDB
> -     if (kgdb_flag) {
> -             kgdb_irq = K_INT_UART_0 + kgdb_port;
> -
> -#ifdef CONFIG_SIBYTE_SB1250_DUART    
> -             sb1250_duart_present[kgdb_port] = 0;
> -#endif
> -             /* Setup uart 1 settings, mapper */
> -             bus_writeq(M_DUART_IMR_BRK, IOADDR(A_DUART_IMRREG(kgdb_port)));
> -
> -             sb1250_steal_irq(kgdb_irq);
> -             bus_writeq(IMR_IP6_VAL,
> -                        IOADDR(A_IMR_REGISTER(0, R_IMR_INTERRUPT_MAP_BASE) +
> -                               (kgdb_irq<<3)));
> -             sb1250_unmask_irq(0, kgdb_irq);
> -     }
> -#endif
>  }
> -
> -#ifdef CONFIG_KGDB
> -
> -#include <linux/delay.h>
> -
> -#define duart_out(reg, val)     csr_out32(val, 
> IOADDR(A_DUART_CHANREG(kgdb_port,reg)))
> -#define duart_in(reg)           
> csr_in32(IOADDR(A_DUART_CHANREG(kgdb_port,reg)))
> -
> -void sb1250_kgdb_interrupt(struct pt_regs *regs)
> -{
> -     /*
> -      * Clear break-change status (allow some time for the remote
> -      * host to stop the break, since we would see another
> -      * interrupt on the end-of-break too)
> -      */
> -     kstat_this_cpu.irqs[kgdb_irq]++;
> -     mdelay(500);
> -     duart_out(R_DUART_CMD, V_DUART_MISC_CMD_RESET_BREAK_INT |
> -                             M_DUART_RX_EN | M_DUART_TX_EN);
> -     set_async_breakpoint(&regs->cp0_epc);
> -}
> -
> -#endif       /* CONFIG_KGDB */
> diff -puN arch/mips/sibyte/sb1250/irq_handler.S~mips-lite 
> arch/mips/sibyte/sb1250/irq_handler.S
> --- linux-2.6.13-rc3/arch/mips/sibyte/sb1250/irq_handler.S~mips-lite  
> 2005-07-29 11:55:31.000000000 -0700
> +++ linux-2.6.13-rc3-trini/arch/mips/sibyte/sb1250/irq_handler.S      
> 2005-07-29 11:55:31.000000000 -0700
> @@ -102,7 +102,7 @@
>  2:
>  #endif
>  
> -#ifdef CONFIG_KGDB
> +#ifdef CONFIG_KGDB_SIBYTE
>       /* KGDB (uart 1) interrupt is routed to IP[6] */
>       andi    t1, s0, CAUSEF_IP6
>       beqz    t1, 1f
> diff -puN /dev/null arch/mips/sibyte/sb1250/kgdb_sibyte.c
> --- /dev/null 2005-07-25 10:57:32.312383000 -0700
> +++ linux-2.6.13-rc3-trini/arch/mips/sibyte/sb1250/kgdb_sibyte.c      
> 2005-07-29 11:55:31.000000000 -0700
> @@ -0,0 +1,164 @@
> +/*
> + * arch/mips/sibyte/sb1250/kgdb_sibyte.c
> + *
> + * Author: Manish Lachwani, mlachwani@mvista.com or manish@koffee-break.com
> + *
> + * 2004 (c) MontaVista Software, Inc. This file is licensed under
> + * the terms of the GNU General Public License version 2. This program
> + * is licensed "as is" without any warranty of any kind, whether express
> + * or implied.
> + */
> +
> +/*
> + * Support for KGDB on the Broadcom Sibyte. The SWARM board
> + * for example does not have a 8250/16550 compatible serial
> + * port. Hence, we need to have a driver for the serial
> + * ports to handle KGDB.  This board needs nothing in addition
> + * to what is normally provided by the gdb portion of the stub.
> + */
> +
> +#include <linux/delay.h>
> +#include <linux/kernel_stat.h>
> +#include <linux/init.h>
> +#include <linux/kgdb.h>
> +
> +#include <asm/io.h>
> +#include <asm/sibyte/sb1250.h>
> +#include <asm/sibyte/sb1250_regs.h>
> +#include <asm/sibyte/sb1250_uart.h>
> +#include <asm/sibyte/sb1250_int.h>
> +#include <asm/addrspace.h>
> +
> +int kgdb_port = 1;
> +static int kgdb_irq;
> +
> +extern char sb1250_duart_present[];
> +extern int sb1250_steal_irq(int irq);
> +
> +/* Forward declarations. */
> +static void kgdbsibyte_init_duart(void);
> +static int kgdb_init_io(void);
> +
> +#define IMR_IP6_VAL  K_INT_MAP_I4
> +#define      duart_out(reg, val)     csr_out32(val, 
> IOADDR(A_DUART_CHANREG(kgdb_port,reg)))
> +#define duart_in(reg)                
> csr_in32(IOADDR(A_DUART_CHANREG(kgdb_port,reg)))
> +
> +static void kgdb_swarm_write_char(int c)
> +{
> +     while ((duart_in(R_DUART_STATUS) & M_DUART_TX_RDY) == 0) ;
> +     duart_out(R_DUART_TX_HOLD, c);
> +}
> +
> +static int kgdb_swarm_read_char(void)
> +{
> +     int ret_char;
> +     unsigned int status;
> +
> +     status = duart_in(R_DUART_STATUS);
> +     while ((status & M_DUART_RX_RDY) == 0) {
> +             status = duart_in(R_DUART_STATUS);
> +     }
> +
> +     /*
> +      * Check for framing error
> +      */
> +     if (status & M_DUART_FRM_ERR) {
> +             kgdbsibyte_init_duart();
> +             kgdb_swarm_write_char('-');
> +             return '-';
> +     }
> +
> +     ret_char = duart_in(R_DUART_RX_HOLD);
> +
> +     return ret_char;
> +}
> +
> +void sb1250_kgdb_interrupt(struct pt_regs *regs)
> +{
> +     int kgdb_irq = K_INT_UART_0 + kgdb_port;
> +     /*
> +      * Clear break-change status (allow some time for the remote
> +      * host to stop the break, since we would see another
> +      * interrupt on the end-of-break too)
> +      */
> +     kstat_this_cpu.irqs[kgdb_irq]++;
> +     mdelay(500);
> +     duart_out(R_DUART_CMD, V_DUART_MISC_CMD_RESET_BREAK_INT |
> +               M_DUART_RX_EN | M_DUART_TX_EN);
> +     if (kgdb_io_ops.init != kgdb_init_io) {
> +             /* Throw away the data if another I/O routine is
> +              * active.
> +              */
> +             unsigned int status;
> +
> +             status = duart_in(R_DUART_STATUS);
> +             while ((status & M_DUART_RX_RDY) == 0) {
> +                     status = duart_in(R_DUART_STATUS);
> +             }
> +             /*
> +              * Check for framing error
> +              */
> +             if (status & M_DUART_FRM_ERR) {
> +                     kgdbsibyte_init_duart();
> +             }
> +             duart_in(R_DUART_RX_HOLD);
> +     } else
> +             breakpoint();
> +
> +}
> +
> +/*
> + * We use port #1 and we set it for 115200 BAUD, 8n1.
> + */
> +static void kgdbsibyte_init_duart(void)
> +{
> +     /* Set 8n1. */
> +     duart_out(R_DUART_MODE_REG_1,
> +               V_DUART_BITS_PER_CHAR_8 | V_DUART_PARITY_MODE_NONE);
> +     duart_out(R_DUART_MODE_REG_2, M_DUART_STOP_BIT_LEN_1);
> +     /* Set baud rate of 115200. */
> +     duart_out(R_DUART_CLK_SEL, V_DUART_BAUD_RATE(115200));
> +     /* Enable rx and tx */
> +     duart_out(R_DUART_CMD, M_DUART_RX_EN | M_DUART_TX_EN);
> +}
> +
> +static int kgdb_init_io(void)
> +{
> +#ifdef CONFIG_SIBYTE_SB1250_DUART
> +     sb1250_duart_present[kgdb_port] = 0;
> +#endif
> +
> +     kgdbsibyte_init_duart();
> +
> +     return 0;
> +}
> +
> +/*
> + * Hookup our IRQ line.  We will already have been initialized a
> + * this point.
> + */
> +static void __init kgdbsibyte_hookup_irq(void)
> +{
> +     /* Steal the IRQ. */
> +     kgdb_irq = K_INT_UART_0 + kgdb_port;
> +
> +     /* Setup uart 1 settings, mapper */
> +     __raw_writeq(M_DUART_IMR_BRK, IOADDR(A_DUART_IMRREG(kgdb_port)));
> +
> +     sb1250_steal_irq(kgdb_irq);
> +
> +     __raw_writeq(IMR_IP6_VAL,
> +                  IOADDR(A_IMR_REGISTER(0, R_IMR_INTERRUPT_MAP_BASE) +
> +                         (kgdb_irq << 3)));
> +
> +     sb1250_unmask_irq(0, kgdb_irq);
> +}
> +
> +struct kgdb_io kgdb_io_ops = {
> +     .read_char = kgdb_swarm_read_char,
> +     .write_char = kgdb_swarm_write_char,
> +     .init = kgdb_init_io,
> +     .late_init = kgdbsibyte_hookup_irq,
> +     .pre_exception = NULL,
> +     .post_exception = NULL
> +};
> diff -puN arch/mips/sibyte/sb1250/Makefile~mips-lite 
> arch/mips/sibyte/sb1250/Makefile
> --- linux-2.6.13-rc3/arch/mips/sibyte/sb1250/Makefile~mips-lite       
> 2005-07-29 11:55:31.000000000 -0700
> +++ linux-2.6.13-rc3-trini/arch/mips/sibyte/sb1250/Makefile   2005-07-29 
> 11:55:31.000000000 -0700
> @@ -4,5 +4,6 @@ obj-$(CONFIG_SMP)                     += smp.o
>  obj-$(CONFIG_SIBYTE_TBPROF)          += bcm1250_tbprof.o
>  obj-$(CONFIG_SIBYTE_STANDALONE)              += prom.o
>  obj-$(CONFIG_SIBYTE_BUS_WATCHER)     += bus_watcher.o
> +obj-$(CONFIG_KGDB_SIBYTE)            += kgdb_sibyte.o
>  
>  EXTRA_AFLAGS := $(CFLAGS)
> diff -L arch/mips/sibyte/swarm/dbg_io.c -puN 
> arch/mips/sibyte/swarm/dbg_io.c~mips-lite /dev/null
> --- linux-2.6.13-rc3/arch/mips/sibyte/swarm/dbg_io.c
> +++ /dev/null 2005-07-25 10:57:32.312383000 -0700
> @@ -1,76 +0,0 @@
> -/*
> - * kgdb debug routines for SiByte boards.
> - *
> - * Copyright (C) 2001 MontaVista Software Inc.
> - * Author: Jun Sun, jsun@mvista.com or jsun@junsun.net
> - *
> - * This program is free software; you can redistribute  it and/or modify it
> - * under  the terms of  the GNU General  Public License as published by the
> - * Free Software Foundation;  either version 2 of the  License, or (at your
> - * option) any later version.
> - *
> - */
> -
> -/* -------------------- BEGINNING OF CONFIG --------------------- */
> -
> -#include <linux/delay.h>
> -#include <asm/io.h>
> -#include <asm/sibyte/sb1250.h>
> -#include <asm/sibyte/sb1250_regs.h>
> -#include <asm/sibyte/sb1250_uart.h>
> -#include <asm/sibyte/sb1250_int.h>
> -#include <asm/addrspace.h>
> -
> -/*
> - * We use the second serial port for kgdb traffic.
> - *   115200, 8, N, 1.
> - */
> -
> -#define      BAUD_RATE               115200
> -#define      CLK_DIVISOR             V_DUART_BAUD_RATE(BAUD_RATE)
> -#define      DATA_BITS               V_DUART_BITS_PER_CHAR_8         /* or 7 
>    */
> -#define      PARITY                  V_DUART_PARITY_MODE_NONE        /* or 
> even */
> -#define      STOP_BITS               M_DUART_STOP_BIT_LEN_1          /* or 2 
>    */
> -
> -static int duart_initialized = 0;    /* 0: need to be init'ed by kgdb */
> -
> -/* -------------------- END OF CONFIG --------------------- */
> -extern int kgdb_port;
> -
> -#define      duart_out(reg, val)     csr_out32(val, 
> IOADDR(A_DUART_CHANREG(kgdb_port,reg)))
> -#define duart_in(reg)                
> csr_in32(IOADDR(A_DUART_CHANREG(kgdb_port,reg)))
> -
> -void putDebugChar(unsigned char c);
> -unsigned char getDebugChar(void);
> -static void
> -duart_init(int clk_divisor, int data, int parity, int stop)
> -{
> -     duart_out(R_DUART_MODE_REG_1, data | parity);
> -     duart_out(R_DUART_MODE_REG_2, stop);
> -     duart_out(R_DUART_CLK_SEL, clk_divisor);
> -
> -     duart_out(R_DUART_CMD, M_DUART_RX_EN | M_DUART_TX_EN);  /* enable rx 
> and tx */
> -}
> -
> -void
> -putDebugChar(unsigned char c)
> -{
> -     if (!duart_initialized) {
> -             duart_initialized = 1;
> -             duart_init(CLK_DIVISOR, DATA_BITS, PARITY, STOP_BITS);
> -     }
> -     while ((duart_in(R_DUART_STATUS) & M_DUART_TX_RDY) == 0);
> -     duart_out(R_DUART_TX_HOLD, c);
> -}
> -
> -unsigned char
> -getDebugChar(void)
> -{
> -     if (!duart_initialized) {
> -             duart_initialized = 1;
> -             duart_init(CLK_DIVISOR, DATA_BITS, PARITY, STOP_BITS);
> -     }
> -     while ((duart_in(R_DUART_STATUS) & M_DUART_RX_RDY) == 0) ;
> -     return duart_in(R_DUART_RX_HOLD);
> -}
> -
> diff -puN arch/mips/sibyte/swarm/Makefile~mips-lite 
> arch/mips/sibyte/swarm/Makefile
> --- linux-2.6.13-rc3/arch/mips/sibyte/swarm/Makefile~mips-lite        
> 2005-07-29 11:55:31.000000000 -0700
> +++ linux-2.6.13-rc3-trini/arch/mips/sibyte/swarm/Makefile    2005-07-29 
> 11:55:31.000000000 -0700
> @@ -1,3 +1 @@
>  lib-y                                = setup.o rtc_xicor1241.o rtc_m41t81.o
> -
> -lib-$(CONFIG_KGDB)           += dbg_io.o
> diff -puN /dev/null include/asm-mips/kdebug.h
> --- /dev/null 2005-07-25 10:57:32.312383000 -0700
> +++ linux-2.6.13-rc3-trini/include/asm-mips/kdebug.h  2005-07-29 
> 11:55:31.000000000 -0700
> @@ -0,0 +1,47 @@
> +/*
> + *
> + * Copyright (C) 2004  MontaVista Software Inc.
> + * Author: Manish Lachwani, mlachwani@mvista.com or manish@koffee-break.com
> + *
> + * This program is free software; you can redistribute  it and/or modify it
> + * under  the terms of  the GNU General  Public License as published by the
> + * Free Software Foundation;  either version 2 of the  License, or (at your
> + * option) any later version.
> + *
> + */
> +#ifndef _MIPS_KDEBUG_H
> +#define _MIPS_KDEBUG_H
> +
> +#include <linux/notifier.h>
> +
> +struct pt_regs;
> +
> +struct die_args {
> +     struct pt_regs *regs;
> +     const char *str;
> +     long err;
> +};
> +
> +int register_die_notifier(struct notifier_block *nb);
> +extern struct notifier_block *mips_die_chain;
> +
> +enum die_val {
> +     DIE_OOPS = 1,
> +     DIE_PANIC,
> +     DIE_DIE,
> +     DIE_KERNELDEBUG,
> +     DIE_TRAP,
> +     DIE_PAGE_FAULT,
> +};
> +
> +/*
> + * trap number can be computed from regs and signr can be computed using
> + * compute_signal()
> + */
> +static inline int notify_die(enum die_val val,char *str,struct pt_regs 
> *regs,long err)
> +{
> +     struct die_args args = { .regs=regs, .str=str, .err=err };
> +     return notifier_call_chain(&mips_die_chain, val, &args);
> +}
> +
> +#endif /* _MIPS_KDEBUG_H */
> diff -puN /dev/null include/asm-mips/kgdb.h
> --- /dev/null 2005-07-25 10:57:32.312383000 -0700
> +++ linux-2.6.13-rc3-trini/include/asm-mips/kgdb.h    2005-07-29 
> 12:48:10.000000000 -0700
> @@ -0,0 +1,22 @@
> +#ifdef __KERNEL__
> +#ifndef _ASM_KGDB_H_
> +#define _ASM_KGDB_H_
> +
> +#define BUFMAX                       2048
> +#define NUMREGBYTES          (90*sizeof(long))
> +#define NUMCRITREGBYTES              (12*sizeof(long))
> +#define BREAK_INSTR_SIZE     4
> +#define BREAKPOINT()         __asm__ __volatile__(           \
> +                                     ".globl breakinst\n\t"  \
> +                                     ".set\tnoreorder\n\t"   \
> +                                     "nop\n"                 \
> +                                     "breakinst:\tbreak\n\t" \
> +                                     "nop\n\t"               \
> +                                     ".set\treorder")
> +#define CHECK_EXCEPTION_STACK()      1
> +#define CACHE_FLUSH_IS_SAFE  0
> +
> +extern int kgdb_early_setup;
> +
> +#endif                               /* _ASM_KGDB_H_ */
> +#endif                               /* __KERNEL__ */
> diff -puN lib/Kconfig.debug~mips-lite lib/Kconfig.debug
> --- linux-2.6.13-rc3/lib/Kconfig.debug~mips-lite      2005-07-29 
> 11:55:31.000000000 -0700
> +++ linux-2.6.13-rc3-trini/lib/Kconfig.debug  2005-07-29 13:23:57.000000000 
> -0700
> @@ -163,7 +163,7 @@ config FRAME_POINTER
>  
>  config KGDB
>       bool "KGDB: kernel debugging with remote gdb"
> -     depends on DEBUG_KERNEL && (X86 || ((!SMP || BROKEN) && (PPC32)))
> +     depends on DEBUG_KERNEL && (X86 || MIPS32 || ((!SMP || BROKEN) && 
> PPC32))
>       help
>         If you say Y here, it will be possible to remotely debug the
>         kernel using gdb. It is strongly suggested that you enable
> @@ -189,6 +189,7 @@ choice
>       prompt "Method for KGDB communication"
>       depends on KGDB
>       default KGDB_ONLY_MODULES
> +     default KGDB_SIBYTE if SIBYTE_SB1xxx_SOC
>       default KGDB_MPSC if SERIAL_MPSC
>       help
>         There are a number of different ways in which you can communicate
> @@ -222,6 +223,10 @@ config KGDB_MPSC
>         Controller (MPSC) channel. Note that the GT64260A is not
>         supported.
>  
> +config KGDB_SIBYTE
> +     bool "KGDB: On the Broadcom SWARM serial port"
> +     depends on MIPS && SIBYTE_SB1xxx_SOC
> +
>  endchoice
>  
>  config KGDB_8250
> _

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