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Re: Illegal instruction

To: Jun Sun <jsun@mvista.com>
Subject: Re: Illegal instruction
From: Carsten Langgaard <carstenl@mips.com>
Date: Tue, 10 Jul 2001 13:14:12 +0200
Cc: ralf@oss.sgi.com, vhouten@kpn.com, linux-mips@oss.sgi.com, "H . J . Lu" <hjl@lucon.org>
References: <3B4573B8.9F89022B@mips.com> <3B4635FB.1ED5D222@mvista.com>
Sender: owner-linux-mips@oss.sgi.com
Thanks, that did the trick.
Now I would like to try to install H.J. Lu's RedHat7.1 RPM packages.
If I just do a:
    rpm -Uvh --root /mnt/harddisk *.rpm
then it fails on a lot of dependencies. If I try to force the install like this:
    rpm -Uvh --nodeps --force --root /mnt/harddisk *.rpm
then it actually install a lot of the RPMs, but still some fails, because it 
actually need
then dependencies.
If I try to redo the above it seems to go better the second time, because a lot 
of the
dependencies is solved (installed).
Is this really the way to install a set of RPMs like this or is there a better 
way?

/Carsten

Jun Sun wrote:

> Carsten Langgaard wrote:
> >
> > Hi Karel,
> >
> > I have tried the root-images tar-files: mipselroot-rh7-20010606 and
> > mipsroot-rh7.
> > The mipsroot-rh7 (bigendian) root image seem to work fine, but when
> > I use the mipselroot-rh7-20010606 (littleendian) I get an illegal
> > instruction.
> > [cat:179] Illegal instruction 7c010001 at 2ac8b20c ra=00000000.
> >
> > I'm using a 2.4.3 kernel.
> > Anyone got an idea ?
> >
> > /Carsten
> >
>
> Is the userland compiled with MIPS I option?  I bet this is the same nasty
> MIPS_ATOMIC_SET bug.
>
> Currently, there are three fixes.  One is from Florian, which only takes care
> of CPUs with ll/sc.  Another is from Maceij, which introduces a new syscall,
> and some changes in glibc.  The thrid is mine, a compromising one.  It takes
> care of both ll/sc case and non-llsc case, has minimum change, and practically
> makes all programs happy.
>
> Ralf, please take at least one of the fixes.  Even a not-so-good fix is better
> than no fix.
>
> Jun
>
>   ------------------------------------------------------------------------
>
> This is a compromising fix for sysmips(MIPS_ATOMIC_SET, ...).  It
> forces SIGSYS when the return value is a small negative value.  This
> limit is OK for glibc.
>
> Jun
>
> diff -Nru linux/arch/mips/kernel/sysmips.c.orig 
> linux/arch/mips/kernel/sysmips.c
> --- linux/arch/mips/kernel/sysmips.c.orig       Mon Apr 23 11:32:54 2001
> +++ linux/arch/mips/kernel/sysmips.c    Tue Jun 26 11:50:48 2001
> @@ -16,7 +16,7 @@
>  #include <linux/sched.h>
>  #include <linux/string.h>
>  #include <linux/utsname.h>
> -
> +#include <linux/signal.h>
>  #include <asm/cachectl.h>
>  #include <asm/pgalloc.h>
>  #include <asm/sysmips.h>
> @@ -75,53 +75,83 @@
>         }
>
>         case MIPS_ATOMIC_SET: {
> -#ifdef CONFIG_CPU_HAS_LLSC
> -               unsigned int tmp;
> +               int *ptr, val, ret, err, tmp;
> +               struct siginfo info;
>
> -               p = (int *) arg1;
> -               errno = verify_area(VERIFY_WRITE, p, sizeof(*p));
> -               if (errno)
> -                       return errno;
> -               errno = 0;
> -
> -               __asm__(".set\tpush\t\t\t# sysmips(MIPS_ATOMIC, ...)\n\t"
> -                       ".set\tmips2\n\t"
> -                       ".set\tnoat\n\t"
> -                       "1:\tll\t%0, %4\n\t"
> -                       "move\t$1, %3\n\t"
> -                       "2:\tsc\t$1, %1\n\t"
> -                       "beqz\t$1, 1b\n\t"
> -                       ".set\tpop\n\t"
> -                       ".section\t.fixup,\"ax\"\n"
> -                       "3:\tli\t%2, 1\t\t\t# error\n\t"
> -                       ".previous\n\t"
> -                       ".section\t__ex_table,\"a\"\n\t"
> -                       ".word\t1b, 3b\n\t"
> -                       ".word\t2b, 3b\n\t"
> -                       ".previous\n\t"
> -                       : "=&r" (tmp), "=o" (* (u32 *) p), "=r" (errno)
> -                       : "r" (arg2), "o" (* (u32 *) p), "2" (errno)
> -                       : "$1");
> +               ptr = (int *)arg1;
> +               val = (int)arg2;
>
> -               if (errno)
> -                       return -EFAULT;
> +               /* Don't emulate unaligned accesses. */
> +               if ((int)ptr & 3) {
> +                       info.si_signo = SIGBUS;
> +                        info.si_code = BUS_ADRALN;
> +                       goto fault;
> +               }
> +
> +               /* A zero here saves us three instructions. */
> +               err = verify_area(VERIFY_WRITE, ptr, 0);
> +               if (err) {
> +                        info.si_signo = SIGSEGV;
> +                       info.si_code = SEGV_ACCERR;
> +                       goto fault;
> +               }
>
> -               /* We're skipping error handling etc.  */
> -               if (current->ptrace & PT_TRACESYS)
> -                       syscall_trace();
> -
> -               ((struct pt_regs *)&cmd)->regs[2] = tmp;
> -               ((struct pt_regs *)&cmd)->regs[7] = 0;
> -
> -               __asm__ __volatile__(
> -                       "move\t$29, %0\n\t"
> -                       "j\to32_ret_from_sys_call"
> -                       : /* No outputs */
> -                       : "r" (&cmd));
> -               /* Unreached */
> +#ifdef CONFIG_CPU_HAS_LLSC
> +               __asm__(".set   mips2\n\t"
> +                       "1:\n\t"
> +                       "ll     %0,%5\n\t"
> +                       ".set   push\n\t"
> +                       ".set   noreorder\n\t"
> +                       "beq    %0,%4,3f\n\t"
> +                       " move  %3,%4\n"
> +                       ".set   pop\n\t"
> +                       "2:\n\t"
> +                       "sc     %3,%1\n\t"
> +                       "beqz   %3,1b\n\t"
> +                       "3:\n\t"
> +                       ".set   mips0\n\t"
> +                       ".section .fixup,\"ax\"\n"
> +                       "4:\n\t"
> +                       "li     %2,%7\n\t"
> +                       "j      3b\n\t"
> +                       ".previous\n\t"
> +                       ".section __ex_table,\"a\"\n\t"
> +                       ".word  1b,4b\n\t"
> +                       ".word  2b,4b\n\t"
> +                       ".previous"
> +                       : "=&r" (ret), "=R" (*ptr), "=r" (err), "=&r" (tmp)
> +                       : "r" (val), "1" (*ptr), "2" (0), "i" (-EFAULT));
>  #else
> -       printk("sys_sysmips(MIPS_ATOMIC_SET, ...) not ready for 
> !CONFIG_CPU_HAS_LLSC\n");
> +               save_and_cli(tmp);
> +               err = __get_user(ret, ptr);
> +               if (ret != val)
> +               err |= __put_user(val, ptr);    /* No fault
> +                                                   unless unwriteable. */
> +               restore_flags(tmp);
>  #endif
> +
> +               if (err) {
> +                        info.si_signo = SIGSEGV;
> +                       info.si_code = SEGV_MAPERR;
> +                       goto fault;
> +               }
> +
> +               if ( (ret < 0) && (ret >= -EMAXERRNO) ) {
> +                        info.si_signo = SIGSYS;
> +                       info.si_code = 0;
> +                       goto fault;
> +               }
> +
> +               return ret;
> +
> +fault:
> +               /* Go back to SYSCALL. */
> +               ((struct pt_regs *)&cmd)->cp0_epc -= 4;
> +
> +               info.si_addr = (void *)((struct pt_regs *)&cmd)->cp0_epc;
> +               force_sig_info(info.si_signo, &info, current);
> +
> +               return 0;
>         }
>
>         case MIPS_FIXADE:
>
>   ------------------------------------------------------------------------
> diff -Nur linux.orig/arch/mips/kernel/Makefile linux/arch/mips/kernel/Makefile
> --- linux.orig/arch/mips/kernel/Makefile        Mon Apr  9 00:23:08 2001
> +++ linux/arch/mips/kernel/Makefile     Mon Apr  9 00:23:34 2001
> @@ -20,7 +20,7 @@
>  obj-y                          += branch.o process.o signal.o entry.o \
>                                    traps.o ptrace.o vm86.o ioport.o reset.o \
>                                    semaphore.o setup.o syscall.o sysmips.o \
> -                                  ipc.o scall_o32.o unaligned.o
> +                                  ipc.o scall_o32.o unaligned.o 
> fast-sysmips.o
>  obj-$(CONFIG_MODULES)          += mips_ksyms.o
>
>  ifdef CONFIG_CPU_R3000
> @@ -69,5 +69,6 @@
>
>  entry.o: entry.S
>  head.o: head.S
> +fast-sysmips.o: fast-sysmips.S
>
>  include $(TOPDIR)/Rules.make
> diff -Nur linux.orig/arch/mips/kernel/fast-sysmips.S 
> linux/arch/mips/kernel/fast-sysmips.S
> --- linux.orig/arch/mips/kernel/fast-sysmips.S  Thu Jan  1 01:00:00 1970
> +++ linux/arch/mips/kernel/fast-sysmips.S       Mon Apr  9 00:28:20 2001
> @@ -0,0 +1,85 @@
> +/*
> + * MIPS_ATOMIC_SET asm implementation for ll/sc capable cpus
> + *
> + * This file is subject to the terms and conditions of the GNU General Public
> + * License.  See the file "COPYING" in the main directory of this archive
> + * for more details.
> + *
> + * Copyright (C) 2001 Florian Lohoff <flo@rfc822.org>
> + *
> + */
> +#include <asm/asm.h>
> +#include <asm/mipsregs.h>
> +#include <asm/regdef.h>
> +#include <asm/stackframe.h>
> +#include <asm/isadep.h>
> +#include <asm/unistd.h>
> +#include <asm/sysmips.h>
> +#include <asm/offset.h>
> +#include <asm/errno.h>
> +
> +#define PT_TRACESYS     0x00000002
> +
> +       EXPORT(fast_sysmips)
> +
> +       .set    noreorder
> +
> +       li      t0, MIPS_ATOMIC_SET
> +       beq     a0, t0, 1f
> +        nop
> +       j       sys_sysmips
> +        nop
> +
> +1:
> +
> +       # a0 - MIPS_ATOMIC_SET
> +       # a1 - mem ptr
> +       # a2 - value
> +
> +       addiu   sp, sp, -8                      # Reserve space
> +       sw      a0, (sp)                        # Save arg0
> +
> +       addiu   a0, a1, 4                       # addr+size
> +       ori     v0, a1, 4                       # addr | size
> +       lw      v1, THREAD_CURDS(gp)            # current->thread.current_ds
> +       or      v0, v0, a0                      # addr | size | (addr+size)
> +       and     v1, v1, v0                      # (mask)&(addr | size | 
> (addr+size)
> +       bltz    v1, 5f
> +        nop
> +
> +2:
> +       ll      v0, (a1)
> +       move    t0, a2
> +       sc      t0, (a1)
> +       beqz    t0, 2b
> +        nop
> +
> +       sw      v0, PT_R2+8(sp)                 # Result value
> +       sw      zero, PT_R7+8(sp)               # Success indicator
> +
> +       lw      t0, TASK_PTRACE(gp)             # syscall tracing enabled?
> +       andi    t0, PT_TRACESYS
> +       bnez    t0, 3f
> +        nop
> +
> +4:
> +       lw      a0, (sp)                        # Restore arg0
> +       addiu   sp, sp, 8                       # Restore sp
> +
> +       j       o32_ret_from_sys_call
> +        nop
> +
> +3:
> +       sw      ra, 4(sp)
> +       jal     syscall_trace
> +        nop
> +       lw      ra, 4(sp)
> +       j       4b
> +        nop
> +
> +5:
> +       lw      a0, (sp)                        # Restore arg0
> +       addiu   sp, sp, 8                       # Restore sp
> +       j       ra
> +        li     v0, -EFAULT
> +
> diff -Nur linux.orig/arch/mips/kernel/irix5sys.h 
> linux/arch/mips/kernel/irix5sys.h
> --- linux.orig/arch/mips/kernel/irix5sys.h      Mon Apr  9 00:16:29 2001
> +++ linux/arch/mips/kernel/irix5sys.h   Sun Apr  8 21:21:16 2001
> @@ -69,7 +69,7 @@
>  SYS(irix_getgid, 0)                    /* 1047  getgid()              V*/
>  SYS(irix_unimp, 0)                     /* 1048  (XXX IRIX 4 ssig)     V*/
>  SYS(irix_msgsys, 6)                    /* 1049  sys_msgsys            V*/
> -SYS(sys_sysmips, 4)                    /* 1050  sysmips()            HV*/
> +SYS(fast_sysmips, 4)                   /* 1050  sysmips()            HV*/
>  SYS(irix_unimp, 0)                     /* 1051  XXX sysacct()        IV*/
>  SYS(irix_shmsys, 5)                    /* 1052  sys_shmsys            V*/
>  SYS(irix_semsys, 0)                    /* 1053  sys_semsys            V*/
> diff -Nur linux.orig/arch/mips/kernel/syscalls.h 
> linux/arch/mips/kernel/syscalls.h
> --- linux.orig/arch/mips/kernel/syscalls.h      Mon Apr  9 00:16:30 2001
> +++ linux/arch/mips/kernel/syscalls.h   Sun Apr  8 21:21:43 2001
> @@ -163,7 +163,7 @@
>  SYS(sys_writev, 3)
>  SYS(sys_cacheflush, 3)
>  SYS(sys_cachectl, 3)
> -SYS(sys_sysmips, 4)
> +SYS(fast_sysmips, 4)
>  SYS(sys_ni_syscall, 0)                         /* 4150 */
>  SYS(sys_getsid, 1)
>  SYS(sys_fdatasync, 0)

--
_    _ ____  ___   Carsten Langgaard   Mailto:carstenl@mips.com
|\  /|||___)(___   MIPS Denmark        Direct: +45 4486 5527
| \/ |||    ____)  Lautrupvang 4B      Switch: +45 4486 5555
  TECHNOLOGIES     2750 Ballerup       Fax...: +45 4486 5556
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