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Re: gcc 3.3.4/3.4.1 and get_user

To: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Subject: Re: gcc 3.3.4/3.4.1 and get_user
From: Ralf Baechle <ralf@linux-mips.org>
Date: Fri, 12 Nov 2004 14:44:40 +0100
Cc: linux-mips@linux-mips.org
In-reply-to: <20041104.153744.122623401.nemoto@toshiba-tops.co.jp>
Original-recipient: rfc822;linux-mips@linux-mips.org
References: <87656yqsmz.fsf@redhat.com> <20040920154042.GB5150@linux-mips.org> <20040920171021.GA25371@linux-mips.org> <20041104.153744.122623401.nemoto@toshiba-tops.co.jp>
Sender: linux-mips-bounce@linux-mips.org
User-agent: Mutt/1.4.1i
On Thu, Nov 04, 2004 at 03:37:44PM +0900, Atsushi Nemoto wrote:

Slow answer - but not forgotten :-)

> ralf> And here the same for 2.4.  Actually this is a straight backport
> ralf> of the 2.6 uaccess.h to 2.4 so with this patch
> ralf> include/asm-mips/uaccess.h and include/asm-mips64/uaccess.h are
> ralf> going to be identical.
> 
> I found that asm-mips/uaccess.h and asm-mips64/uaccess.h in 2.4 are
> sill not identical.  Is this intentional?  Current
> asm-mips64/uaccess.h seems broken...

They were both supposed to be identical.

> Also, arch/mips64/lib/strxxx_user.S should be modified to use t0/t1
> instead of ta0/ta1 ? (__UA_t0 is now $12, not $8)

Right, part of the same mistake.  See the patch below which gets my test
system working.  The 32-bit parts are cosmetic and shouldn't change the
generated code.  They just make the 32-bit and 64-bit str*_user.S files
almost identical.

I'm surprised somebody still cares about 2.4 64-bit ;-)  The 64-bit
improvments in 2.6, especially in the area of the 32-bit compatibility
code are so substancial that I don't think 2.4 is still a good choice.

  Ralf

Index: arch/mips/lib/strlen_user.S
===================================================================
RCS file: /home/cvs/linux/arch/mips/lib/strlen_user.S,v
retrieving revision 1.6.2.1
diff -u -r1.6.2.1 strlen_user.S
--- arch/mips/lib/strlen_user.S 1 Jul 2002 15:27:23 -0000       1.6.2.1
+++ arch/mips/lib/strlen_user.S 12 Nov 2004 13:32:02 -0000
@@ -23,18 +23,18 @@
  * Return 0 for error
  */
 LEAF(__strlen_user_asm)
-       lw      v0, THREAD_CURDS($28)   # pointer ok?
-       and     v0, a0
-       bltz    v0, fault
+       LONG_L          v0, THREAD_CURDS($28)   # pointer ok?
+       and             v0, a0
+       bltz            v0, fault
 
 FEXPORT(__strlen_user_nocheck_asm)
-       move    v0, a0
+       move            v0, a0
 1:     EX(lb, t0, (v0), fault)
-       addiu   v0, 1
-       bnez    t0, 1b
-       subu    v0, a0
-       jr      ra
+       addiu           v0, 1
+       bnez            t0, 1b
+       subu            v0, a0
+       jr              ra
        END(__strlen_user_asm)
 
-fault: move    v0, zero
-       jr      ra
+fault: move            v0, zero
+       jr              ra
Index: arch/mips/lib/strncpy_user.S
===================================================================
RCS file: /home/cvs/linux/arch/mips/lib/strncpy_user.S,v
retrieving revision 1.5
diff -u -r1.5 strncpy_user.S
--- arch/mips/lib/strncpy_user.S        6 Sep 2001 13:12:02 -0000       1.5
+++ arch/mips/lib/strncpy_user.S        12 Nov 2004 13:32:02 -0000
@@ -28,31 +28,31 @@
  */
 
 LEAF(__strncpy_from_user_asm)
-       lw      v0, THREAD_CURDS($28)   # pointer ok?
-       and     v0, a1
-       bltz    v0, fault
+       LONG_L          v0, THREAD_CURDS($28)   # pointer ok?
+       and             v0, a1
+       bltz            v0, fault
 
-EXPORT(__strncpy_from_user_nocheck_asm)
-       move    v0, zero
-       move    v1, a1
-       .set    noreorder
-1:     EX(lbu,  t0, (v1), fault)
-       addiu   v1, v1, 1
-       beqz    t0, 2f
-        sb     t0, (a0)
-       addiu   v0, 1
-       bne     v0, a2, 1b
-        addiu  a0, 1
-       .set    reorder
-2:     addu    t0, a1, v0
-       xor     t0, a1
-       bltz    t0, fault
-       jr      ra                              # return n
+FEXPORT(__strncpy_from_user_nocheck_asm)
+       move            v0, zero
+       move            v1, a1
+       .set            noreorder
+1:     EX(lbu, t0, (v1), fault)
+       PTR_ADDIU       v1, 1
+       beqz            t0, 2f
+        sb             t0, (a0)
+       PTR_ADDIU       v0, 1
+       bne             v0, a2, 1b
+        PTR_ADDIU      a0, 1
+       .set            reorder
+2:     PTR_ADDU        t0, a1, v0
+       xor             t0, a1
+       bltz            t0, fault
+       jr              ra                      # return n
        END(__strncpy_from_user_asm)
 
-fault: li      v0, -EFAULT
-       jr      ra
+fault: li              v0, -EFAULT
+       jr              ra
 
-       .section __ex_table,"a"
-       PTR     1b, fault
+       .section        __ex_table,"a"
+       PTR             1b, fault
        .previous
Index: arch/mips/lib/strnlen_user.S
===================================================================
RCS file: /home/cvs/linux/arch/mips/lib/strnlen_user.S,v
retrieving revision 1.3.2.1
diff -u -r1.3.2.1 strnlen_user.S
--- arch/mips/lib/strnlen_user.S        1 Jul 2002 15:27:23 -0000       1.3.2.1
+++ arch/mips/lib/strnlen_user.S        12 Nov 2004 13:32:02 -0000
@@ -27,23 +27,22 @@
  *       bytes.  There's nothing secret there ...
  */
 LEAF(__strnlen_user_asm)
-       lw      v0, THREAD_CURDS($28)   # pointer ok?
-       and     v0, a0
-       bltz    v0, fault
+       LONG_L          v0, THREAD_CURDS($28)   # pointer ok?
+       and             v0, a0
+       bltz            v0, fault
 
 FEXPORT(__strnlen_user_nocheck_asm)
-       .type   __strnlen_user_nocheck_asm,@function
-       move    v0, a0
-       addu    a1, a0                  # stop pointer
-       .set    noreorder
-1:     beq     v0, a1, 1f              # limit reached?
-        addiu  v0, 1
-       .set    reorder
+       move            v0, a0
+       PTR_ADDU        a1, a0                  # stop pointer
+       .set            noreorder
+1:     beq             v0, a1, 1f              # limit reached?
+        PTR_ADDIU      v0, 1
+       .set            reorder
        EX(lb, t0, -1(v0), fault)
-       bnez    t0, 1b
-1:     subu    v0, a0
-       jr      ra
+       bnez            t0, 1b
+1:     PTR_SUBU        v0, a0
+       jr              ra
        END(__strnlen_user_asm)
 
-fault: move    v0, zero
-       jr      ra
+fault: move            v0, zero
+       jr              ra
Index: arch/mips64/lib/strlen_user.S
===================================================================
RCS file: /home/cvs/linux/arch/mips64/lib/Attic/strlen_user.S,v
retrieving revision 1.4.2.2
diff -u -r1.4.2.2 strlen_user.S
--- arch/mips64/lib/strlen_user.S       9 Dec 2002 21:24:13 -0000       1.4.2.2
+++ arch/mips64/lib/strlen_user.S       12 Nov 2004 13:32:02 -0000
@@ -23,18 +23,18 @@
  * Return 0 for error
  */
 LEAF(__strlen_user_asm)
-       ld      v0, THREAD_CURDS($28)                   # pointer ok?
-       and     v0, a0
-       bnez    v0, fault
+       LONG_L          v0, THREAD_CURDS($28)   # pointer ok?
+       and             v0, a0
+       bnez            v0, fault
 
 FEXPORT(__strlen_user_nocheck_asm)
-       move    v0, a0
-1:     EX(lb, ta0, (v0), fault)
-       daddiu  v0, 1
-       bnez    ta0, 1b
-       dsubu   v0, a0
-       jr      ra
+       move            v0, a0
+1:     EX(lb, t0, (v0), fault)
+       PTR_ADDIU       v0, 1
+       bnez            t0, 1b
+       PTR_SUBU        v0, a0
+       jr              ra
        END(__strlen_user_asm)
 
-fault: move    v0, zero
-       jr      ra
+fault: move            v0, zero
+       jr              ra
Index: arch/mips64/lib/strncpy_user.S
===================================================================
RCS file: /home/cvs/linux/arch/mips64/lib/Attic/strncpy_user.S,v
retrieving revision 1.4.2.1
diff -u -r1.4.2.1 strncpy_user.S
--- arch/mips64/lib/strncpy_user.S      9 Dec 2002 21:24:13 -0000       1.4.2.1
+++ arch/mips64/lib/strncpy_user.S      12 Nov 2004 13:32:02 -0000
@@ -28,31 +28,31 @@
  */
 
 LEAF(__strncpy_from_user_asm)
-       ld      v0, THREAD_CURDS($28)           # pointer ok?
-       and     v0, a1
-       bnez    v0, fault
+       LONG_L          v0, THREAD_CURDS($28)   # pointer ok?
+       and             v0, a1
+       bnez            v0, fault
 
 FEXPORT(__strncpy_from_user_nocheck_asm)
-       move    v0, zero
-       move    v1, a1
-       .set    noreorder
-1:     EX(lbu,  ta0, (v1), fault)
-       daddiu  v1, 1
-       beqz    ta0, 2f
-        sb     ta0, (a0)
-       daddiu  v0, 1
-       bne     v0, a2, 1b
-        daddiu a0, 1
-       .set    reorder
-2:     daddu   ta0, a1, v0
-       xor     ta0, a1
-       bltz    ta0, fault
-       jr      ra                              # return n
+       move            v0, zero
+       move            v1, a1
+       .set            noreorder
+1:     EX(lbu, t0, (v1), fault)
+       PTR_ADDIU       v1, 1
+       beqz            t0, 2f
+        sb             t0, (a0)
+       PTR_ADDIU       v0, 1
+       bne             v0, a2, 1b
+        PTR_ADDIU      a0, 1
+       .set            reorder
+2:     PTR_ADDU        t0, a1, v0
+       xor             t0, a1
+       bltz            t0, fault
+       jr              ra                      # return n
        END(__strncpy_from_user_asm)
 
-fault: li      v0, -EFAULT
-       jr      ra
+fault: li              v0, -EFAULT
+       jr              ra
 
        .section        __ex_table,"a"
-       PTR     1b, fault
+       PTR             1b, fault
        .previous
Index: arch/mips64/lib/strnlen_user.S
===================================================================
RCS file: /home/cvs/linux/arch/mips64/lib/Attic/strnlen_user.S,v
retrieving revision 1.2.2.3
diff -u -r1.2.2.3 strnlen_user.S
--- arch/mips64/lib/strnlen_user.S      9 Dec 2002 21:24:13 -0000       1.2.2.3
+++ arch/mips64/lib/strnlen_user.S      12 Nov 2004 13:32:02 -0000
@@ -20,23 +20,29 @@
 /*
  * Return the size of a string (including the ending 0)
  *
- * Return 0 for error, len on string but at max a1 otherwise
+ * Return 0 for error, len of string but at max a1 otherwise
+ *
+ * Note: for performance reasons we deliberately accept that a user may
+ *       make strlen_user and strnlen_user access the first few KSEG0
+ *       bytes.  There's nothing secret there ...
  */
 LEAF(__strnlen_user_asm)
-       ld      v0, THREAD_CURDS($28)   # pointer ok?
-       and     v0, a0
-       bnez    v0, fault
+       LONG_L          v0, THREAD_CURDS($28)   # pointer ok?
+       and             v0, a0
+       bnez            v0, fault
 
 FEXPORT(__strnlen_user_nocheck_asm)
-       move    v0, a0
-       daddu   a1, a0                  # stop pointer
-1:     beq     v0, a1, 1f              # limit reached?
-       EX(lb, ta0, (v0), fault)
-       daddiu  v0, 1
-       bnez    ta0, 1b
-1:     dsubu   v0, a0
-       jr      ra
+       move            v0, a0
+       PTR_ADDU        a1, a0                  # stop pointer
+       .set            noreorder
+1:     beq             v0, a1, 1f              # limit reached?
+        PTR_ADDIU      v0, 1
+       .set            reorder
+       EX(lb, t0, -1(v0), fault)
+       bnez            t0, 1b
+1:     PTR_SUBU        v0, a0
+       jr              ra
        END(__strnlen_user_asm)
 
-fault: move    v0, zero
-       jr      ra
+fault: move            v0, zero
+       jr              ra
Index: include/asm-mips64/uaccess.h
===================================================================
RCS file: /home/cvs/linux/include/asm-mips64/Attic/uaccess.h,v
retrieving revision 1.13.2.3
diff -u -r1.13.2.3 uaccess.h
--- include/asm-mips64/uaccess.h        5 Jul 2003 03:23:46 -0000       1.13.2.3
+++ include/asm-mips64/uaccess.h        12 Nov 2004 13:32:06 -0000
@@ -3,18 +3,17 @@
  * License.  See the file "COPYING" in the main directory of this archive
  * for more details.
  *
- * Copyright (C) 1996, 1997, 1998, 1999, 2000 by Ralf Baechle
+ * Copyright (C) 1996, 1997, 1998, 1999, 2000, 03, 04 by Ralf Baechle
  * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
  */
 #ifndef _ASM_UACCESS_H
 #define _ASM_UACCESS_H
 
+#include <linux/config.h>
+#include <linux/compiler.h>
 #include <linux/errno.h>
 #include <linux/sched.h>
 
-#define STR(x)  __STR(x)
-#define __STR(x)  #x
-
 /*
  * The fs value determines whether argument validity checking should be
  * performed or not.  If get_fs() == USER_DS, checking is performed, with
@@ -22,15 +21,47 @@
  *
  * For historical reasons, these macros are grossly misnamed.
  */
+#ifdef CONFIG_MIPS32
+
+#define __UA_LIMIT     0x80000000UL
+
+#define __UA_ADDR      ".word"
+#define __UA_LA                "la"
+#define __UA_ADDU      "addu"
+#define __UA_t0                "$8"
+#define __UA_t1                "$9"
+
+#endif /* CONFIG_MIPS32 */
+
+#ifdef CONFIG_MIPS64
+
+#define __UA_LIMIT     (- TASK_SIZE)
+
+#define __UA_ADDR      ".dword"
+#define __UA_LA                "dla"
+#define __UA_ADDU      "daddu"
+#define __UA_t0                "$12"
+#define __UA_t1                "$13"
+
+#endif /* CONFIG_MIPS64 */
+
+/*
+ * USER_DS is a bitmask that has the bits set that may not be set in a valid
+ * userspace address.  Note that we limit 32-bit userspace to 0x7fff8000 but
+ * the arithmetic we're doing only works if the limit is a power of two, so
+ * we use 0x80000000 here on 32-bit kernels.  If a process passes an invalid
+ * address in this range it's the process's problem, not ours :-)
+ */
+
 #define KERNEL_DS      ((mm_segment_t) { 0UL })
-#define USER_DS                ((mm_segment_t) { -TASK_SIZE })
+#define USER_DS                ((mm_segment_t) { __UA_LIMIT })
 
 #define VERIFY_READ    0
 #define VERIFY_WRITE   1
 
-#define get_fs()        (current->thread.current_ds)
 #define get_ds()       (KERNEL_DS)
-#define set_fs(x)       (current->thread.current_ds=(x))
+#define get_fs()       (current->thread.current_ds)
+#define set_fs(x)      (current->thread.current_ds = (x))
 
 #define segment_eq(a,b)        ((a).seg == (b).seg)
 
@@ -44,14 +75,12 @@
  *  - AND "size" doesn't have any high-bits set
  *  - AND "addr+size" doesn't have any high-bits set
  *  - OR we are in kernel mode.
+ *
+ * __ua_size() is a trick to avoid runtime checking of positive constant
+ * sizes; for those we already know at compile time that the size is ok.
  */
 #define __ua_size(size)                                                        
\
-       ((__builtin_constant_p(size) && (size)) > 0 ? 0 : (size))
-
-#define __access_ok(addr, size, mask)                                  \
-       (((mask) & ((addr) | ((addr) + (size)) | __ua_size(size))) == 0)
-
-#define __access_mask get_fs().seg
+       ((__builtin_constant_p(size) && (signed long) (size) > 0) ? 0 : (size))
 
 /*
  * access_ok: - Checks if a user space pointer is valid
@@ -72,8 +101,14 @@
  * checks that the pointer is in the user space range - after calling
  * this function, memory access functions may still return -EFAULT.
  */
+
+#define __access_mask get_fs().seg
+
+#define __access_ok(addr, size, mask)                                  \
+       (((signed long)((mask) & ((addr) | ((addr) + (size)) | 
__ua_size(size)))) == 0)
+
 #define access_ok(type, addr, size)                                    \
-       __access_ok((unsigned long)(addr), (size), __access_mask)
+       likely(__access_ok((unsigned long)(addr), (size),__access_mask))
 
 /*
  * verify_area: - Obsolete, use access_ok()
@@ -184,117 +219,177 @@
 struct __large_struct { unsigned long buf[100]; };
 #define __m(x) (*(struct __large_struct *)(x))
 
-#define __get_user_nocheck(x,ptr,size)                         \
-({                                                             \
-       long __gu_err;                                          \
-       __typeof(*(ptr)) __gu_val;                              \
-       long __gu_addr;                                         \
-       __asm__("":"=r" (__gu_val));                            \
-       __gu_addr = (long) (ptr);                               \
-       __asm__("":"=r" (__gu_err));                            \
-       switch (size) {                                         \
-               case 1: __get_user_asm("lb"); break;            \
-               case 2: __get_user_asm("lh"); break;            \
-               case 4: __get_user_asm("lw"); break;            \
-               case 8: __get_user_asm("ld"); break;            \
-               default: __get_user_unknown(); break;           \
-       } x = (__typeof__(*(ptr))) __gu_val;                    \
-       __gu_err;                                               \
-})
-
-#define __get_user_check(x,ptr,size)                           \
-({                                                             \
-       long __gu_err;                                          \
-       __typeof__(*(ptr)) __gu_val;                            \
-       long __gu_addr;                                         \
-       __asm__("":"=r" (__gu_val));                            \
-       __gu_addr = (long) (ptr);                               \
-       __asm__("":"=r" (__gu_err));                            \
-       if (__access_ok(__gu_addr,size,__access_mask)) {        \
-               switch (size) {                                 \
-               case 1: __get_user_asm("lb"); break;            \
-               case 2: __get_user_asm("lh"); break;            \
-               case 4: __get_user_asm("lw"); break;            \
-               case 8: __get_user_asm("ld"); break;            \
-               default: __get_user_unknown(); break;           \
-               }                                               \
-       } x = (__typeof__(*(ptr))) __gu_val;                    \
-       __gu_err;                                               \
-})
-
-#define __get_user_asm(insn)                                   \
-({                                                             \
-       __asm__ __volatile__(                                   \
-       "1:\t" insn "\t%1,%2\n\t"                               \
-       "move\t%0,$0\n"                                         \
-       "2:\n\t"                                                \
-       ".section\t.fixup,\"ax\"\n"                             \
-       "3:\tli\t%0,%3\n\t"                                     \
-       "move\t%1,$0\n\t"                                       \
-       "j\t2b\n\t"                                             \
-       ".previous\n\t"                                         \
-       ".section\t__ex_table,\"a\"\n\t"                        \
-       ".dword\t1b,3b\n\t"                                     \
-       ".previous"                                             \
-       :"=r" (__gu_err), "=r" (__gu_val)                       \
-       :"o" (__m(__gu_addr)), "i" (-EFAULT));                  \
+/*
+ * Yuck.  We need two variants, one for 64bit operation and one
+ * for 32 bit mode and old iron.
+ */
+#ifdef __mips64
+#define __GET_USER_DW(__gu_err) __get_user_asm("ld", __gu_err)
+#else
+#define __GET_USER_DW(__gu_err) __get_user_asm_ll32(__gu_err)
+#endif
+
+#define __get_user_nocheck(x,ptr,size)                                 \
+({                                                                     \
+       long __gu_err = 0;                                              \
+       __typeof(*(ptr)) __gu_val = 0;                                  \
+       long __gu_addr;                                                 \
+       __gu_addr = (long) (ptr);                                       \
+       switch (size) {                                                 \
+       case 1: __get_user_asm("lb", __gu_err); break;                  \
+       case 2: __get_user_asm("lh", __gu_err); break;                  \
+       case 4: __get_user_asm("lw", __gu_err); break;                  \
+       case 8: __GET_USER_DW(__gu_err); break;                         \
+       default: __get_user_unknown(); break;                           \
+       }                                                               \
+        x = (__typeof__(*(ptr))) __gu_val;                             \
+       __gu_err;                                                       \
+})
+
+#define __get_user_check(x,ptr,size)                                   \
+({                                                                     \
+       __typeof__(*(ptr)) __gu_val = 0;                                \
+       long __gu_addr = (long) (ptr);                                  \
+       long __gu_err;                                                  \
+                                                                       \
+       __gu_err = verify_area(VERIFY_READ, (void *) __gu_addr, size);  \
+                                                                       \
+       if (likely(!__gu_err)) {                                        \
+               switch (size) {                                         \
+               case 1: __get_user_asm("lb", __gu_err); break;          \
+               case 2: __get_user_asm("lh", __gu_err); break;          \
+               case 4: __get_user_asm("lw", __gu_err); break;          \
+               case 8: __GET_USER_DW(__gu_err); break;                 \
+               default: __get_user_unknown(); break;                   \
+               }                                                       \
+       }                                                               \
+       x = (__typeof__(*(ptr))) __gu_val;                              \
+        __gu_err;                                                      \
+})
+
+#define __get_user_asm(insn,__gu_err)                                  \
+({                                                                     \
+       __asm__ __volatile__(                                           \
+       "1:     " insn "        %1, %3                          \n"     \
+       "2:                                                     \n"     \
+       "       .section .fixup,\"ax\"                          \n"     \
+       "3:     li      %0, %4                                  \n"     \
+       "       j       2b                                      \n"     \
+       "       .previous                                       \n"     \
+       "       .section __ex_table,\"a\"                       \n"     \
+       "       "__UA_ADDR "\t1b, 3b                            \n"     \
+       "       .previous                                       \n"     \
+       : "=r" (__gu_err), "=r" (__gu_val)                              \
+       : "0" (__gu_err), "o" (__m(__gu_addr)), "i" (-EFAULT));         \
+})
+
+/*
+ * Get a long long 64 using 32 bit registers.
+ */
+#define __get_user_asm_ll32(__gu_err)                                  \
+({                                                                     \
+       __asm__ __volatile__(                                           \
+       "1:     lw      %1, %3                                  \n"     \
+       "2:     lw      %D1, %4                                 \n"     \
+       "       move    %0, $0                                  \n"     \
+       "3:     .section        .fixup,\"ax\"                   \n"     \
+       "4:     li      %0, %5                                  \n"     \
+       "       move    %1, $0                                  \n"     \
+       "       move    %D1, $0                                 \n"     \
+       "       j       3b                                      \n"     \
+       "       .previous                                       \n"     \
+       "       .section        __ex_table,\"a\"                \n"     \
+       "       " __UA_ADDR "   1b, 4b                          \n"     \
+       "       " __UA_ADDR "   2b, 4b                          \n"     \
+       "       .previous                                       \n"     \
+       : "=r" (__gu_err), "=&r" (__gu_val)                             \
+       : "0" (__gu_err), "o" (__m(__gu_addr)),                         \
+         "o" (__m(__gu_addr + 4)), "i" (-EFAULT));                     \
 })
 
 extern void __get_user_unknown(void);
 
-#define __put_user_nocheck(x,ptr,size)                         \
-({                                                             \
-       long __pu_err;                                          \
-       __typeof__(*(ptr)) __pu_val;                            \
-       long __pu_addr;                                         \
-       __pu_val = (x);                                         \
-       __pu_addr = (long) (ptr);                               \
-       __asm__("":"=r" (__pu_err));                            \
-       switch (size) {                                         \
-               case 1: __put_user_asm("sb"); break;            \
-               case 2: __put_user_asm("sh"); break;            \
-               case 4: __put_user_asm("sw"); break;            \
-               case 8: __put_user_asm("sd"); break;            \
-               default: __put_user_unknown(); break;           \
-       }                                                       \
-       __pu_err;                                               \
-})
-
-#define __put_user_check(x,ptr,size)                           \
-({                                                             \
-       long __pu_err;                                          \
-       __typeof__(*(ptr)) __pu_val;                            \
-       long __pu_addr;                                         \
-       __pu_val = (x);                                         \
-       __pu_addr = (long) (ptr);                               \
-       __asm__("":"=r" (__pu_err));                            \
-       if (__access_ok(__pu_addr,size,__access_mask)) {        \
-               switch (size) {                                 \
-               case 1: __put_user_asm("sb"); break;            \
-               case 2: __put_user_asm("sh"); break;            \
-               case 4: __put_user_asm("sw"); break;            \
-               case 8: __put_user_asm("sd"); break;            \
-               default: __put_user_unknown(); break;           \
-               }                                               \
-       }                                                       \
-       __pu_err;                                               \
-})
-
-#define __put_user_asm(insn)                                   \
-({                                                             \
-       __asm__ __volatile__(                                   \
-       "1:\t" insn "\t%z1, %2\t\t\t# __put_user_asm\n\t"       \
-       "move\t%0, $0\n"                                        \
-       "2:\n\t"                                                \
-       ".section\t.fixup,\"ax\"\n"                             \
-       "3:\tli\t%0, %3\n\t"                                    \
-       "j\t2b\n\t"                                             \
-       ".previous\n\t"                                         \
-       ".section\t__ex_table,\"a\"\n\t"                        \
-       ".dword\t1b, 3b\n\t"                                    \
-       ".previous"                                             \
-       :"=r" (__pu_err)                                        \
-       :"Jr" (__pu_val), "o" (__m(__pu_addr)), "i" (-EFAULT)); \
+/*
+ * Yuck.  We need two variants, one for 64bit operation and one
+ * for 32 bit mode and old iron.
+ */
+#ifdef __mips64
+#define __PUT_USER_DW(__pu_val) __put_user_asm("sd", __pu_val)
+#else
+#define __PUT_USER_DW(__pu_val) __put_user_asm_ll32(__pu_val)
+#endif
+
+#define __put_user_nocheck(x,ptr,size)                                 \
+({                                                                     \
+       long __pu_err = 0;                                              \
+       __typeof__(*(ptr)) __pu_val;                                    \
+       long __pu_addr;                                                 \
+       __pu_val = (x);                                                 \
+       __pu_addr = (long) (ptr);                                       \
+       switch (size) {                                                 \
+       case 1: __put_user_asm("sb", __pu_val); break;                  \
+       case 2: __put_user_asm("sh", __pu_val); break;                  \
+       case 4: __put_user_asm("sw", __pu_val); break;                  \
+       case 8: __PUT_USER_DW(__pu_val); break;                         \
+       default: __put_user_unknown(); break;                           \
+       }                                                               \
+       __pu_err;                                                       \
+})
+
+#define __put_user_check(x,ptr,size)                                   \
+({                                                                     \
+       __typeof__(*(ptr)) __pu_val = (x);                              \
+       long __pu_addr = (long) (ptr);                                  \
+       long __pu_err;                                                  \
+                                                                       \
+       __pu_err = verify_area(VERIFY_WRITE, (void *) __pu_addr, size); \
+                                                                       \
+       if (likely(!__pu_err)) {                                        \
+               switch (size) {                                         \
+               case 1: __put_user_asm("sb", __pu_val); break;          \
+               case 2: __put_user_asm("sh", __pu_val); break;          \
+               case 4: __put_user_asm("sw", __pu_val); break;          \
+               case 8: __PUT_USER_DW(__pu_val); break;                 \
+               default: __put_user_unknown(); break;                   \
+               }                                                       \
+       }                                                               \
+       __pu_err;                                                       \
+})
+
+#define __put_user_asm(insn, __pu_val)                                 \
+({                                                                     \
+       __asm__ __volatile__(                                           \
+       "1:     " insn "        %z2, %3         # __put_user_asm\n"     \
+       "2:                                                     \n"     \
+       "       .section        .fixup,\"ax\"                   \n"     \
+       "3:     li      %0, %4                                  \n"     \
+       "       j       2b                                      \n"     \
+       "       .previous                                       \n"     \
+       "       .section        __ex_table,\"a\"                \n"     \
+       "       " __UA_ADDR "   1b, 3b                          \n"     \
+       "       .previous                                       \n"     \
+       : "=r" (__pu_err)                                               \
+       : "0" (__pu_err), "Jr" (__pu_val), "o" (__m(__pu_addr)),        \
+         "i" (-EFAULT));                                               \
+})
+
+#define __put_user_asm_ll32(__pu_val)                                  \
+({                                                                     \
+       __asm__ __volatile__(                                           \
+       "1:     sw      %2, %3          # __put_user_asm_ll32   \n"     \
+       "2:     sw      %D2, %4                                 \n"     \
+       "3:                                                     \n"     \
+       "       .section        .fixup,\"ax\"                   \n"     \
+       "4:     li      %0, %5                                  \n"     \
+       "       j       3b                                      \n"     \
+       "       .previous                                       \n"     \
+       "       .section        __ex_table,\"a\"                \n"     \
+       "       " __UA_ADDR "   1b, 4b                          \n"     \
+       "       " __UA_ADDR "   2b, 4b                          \n"     \
+       "       .previous"                                              \
+       : "=r" (__pu_err)                                               \
+       : "0" (__pu_err), "r" (__pu_val), "o" (__m(__pu_addr)),         \
+         "o" (__m(__pu_addr + 4)), "i" (-EFAULT));                     \
 })
 
 extern void __put_user_unknown(void);
@@ -304,13 +399,13 @@
  * jump instructions
  */
 #ifdef MODULE
-#define __MODULE_JAL(destination)      \
-       ".set\tnoat\n\t"                \
-       "dla\t$1, " #destination "\n\t" \
-       "jalr\t$1\n\t"                  \
+#define __MODULE_JAL(destination)                                      \
+       ".set\tnoat\n\t"                                                \
+       __UA_LA "\t$1, " #destination "\n\t"                            \
+       "jalr\t$1\n\t"                                                  \
        ".set\tat\n\t"
 #else
-#define __MODULE_JAL(destination)      \
+#define __MODULE_JAL(destination)                                      \
        "jal\t" #destination "\n\t"
 #endif
 
@@ -361,6 +456,9 @@
        __cu_len;                                                       \
 })
 
+#define __copy_to_user_inatomic __copy_to_user
+#define __copy_from_user_inatomic __copy_from_user
+
 /*
  * copy_to_user: - Copy a block of data into user space.
  * @to:   Destination address, in user space.
@@ -402,10 +500,9 @@
        ".set\tnoreorder\n\t"                                           \
        __MODULE_JAL(__copy_user)                                       \
        ".set\tnoat\n\t"                                                \
-       "daddu\t$1, %1, %2\n\t"                                         \
+       __UA_ADDU "\t$1, %1, %2\n\t"                                    \
        ".set\tat\n\t"                                                  \
-       ".set\treorder\n\t"                                             \
-       "move\t%0, $6"                                                  \
+       ".set\treorder"                                                 \
        : "+r" (__cu_to_r), "+r" (__cu_from_r), "+r" (__cu_len_r)       \
        :                                                               \
        : "$8", "$9", "$10", "$11", "$12", "$15", "$24", "$31",         \
@@ -498,19 +595,19 @@
                "move\t%0, $6"
                : "=r" (res)
                : "r" (addr), "r" (size)
-               : "$4", "$5", "$6", "$8", "$9", "$31");
+               : "$4", "$5", "$6", __UA_t0, __UA_t1, "$31");
 
        return res;
 }
 
-#define clear_user(addr,n)                                     \
-({                                                             \
-       void * __cl_addr = (addr);                              \
-       unsigned long __cl_size = (n);                          \
-       if (__cl_size && access_ok(VERIFY_WRITE,                \
-               ((unsigned long)(__cl_addr)), __cl_size))       \
-               __cl_size = __clear_user(__cl_addr, __cl_size); \
-       __cl_size;                                              \
+#define clear_user(addr,n)                                             \
+({                                                                     \
+       void * __cl_addr = (addr);                                      \
+       unsigned long __cl_size = (n);                                  \
+       if (__cl_size && access_ok(VERIFY_WRITE,                        \
+               ((unsigned long)(__cl_addr)), __cl_size))               \
+               __cl_size = __clear_user(__cl_addr, __cl_size);         \
+       __cl_size;                                                      \
 })
 
 /*
@@ -546,7 +643,7 @@
                "move\t%0, $2"
                : "=r" (res)
                : "r" (__to), "r" (__from), "r" (__len)
-               : "$2", "$3", "$4", "$5", "$6", "$8", "$31", "memory");
+               : "$2", "$3", "$4", "$5", "$6", __UA_t0, "$31", "memory");
 
        return res;
 }
@@ -582,7 +679,7 @@
                "move\t%0, $2"
                : "=r" (res)
                : "r" (__to), "r" (__from), "r" (__len)
-               : "$2", "$3", "$4", "$5", "$6", "$8", "$31", "memory");
+               : "$2", "$3", "$4", "$5", "$6", __UA_t0, "$31", "memory");
 
        return res;
 }
@@ -598,7 +695,7 @@
                "move\t%0, $2"
                : "=r" (res)
                : "r" (s)
-               : "$2", "$4", "$8", "$31");
+               : "$2", "$4", __UA_t0, "$31");
 
        return res;
 }
@@ -627,7 +724,24 @@
                "move\t%0, $2"
                : "=r" (res)
                : "r" (s)
-               : "$2", "$4", "$8", "$31");
+               : "$2", "$4", __UA_t0, "$31");
+
+       return res;
+}
+
+/* Returns: 0 if bad, string length+1 (memory size) of string if ok */
+static inline long __strnlen_user(const char *s, long n)
+{
+       long res;
+
+       __asm__ __volatile__(
+               "move\t$4, %1\n\t"
+               "move\t$5, %2\n\t"
+               __MODULE_JAL(__strnlen_user_nocheck_asm)
+               "move\t%0, $2"
+               : "=r" (res)
+               : "r" (s), "r" (n)
+               : "$2", "$4", "$5", __UA_t0, "$31");
 
        return res;
 }
@@ -635,13 +749,16 @@
 /*
  * strlen_user: - Get the size of a string in user space.
  * @str: The string to measure.
- * @n:   The maximum valid length
+ *
+ * Context: User context only.  This function may sleep.
  *
  * Get the size of a NUL-terminated string in user space.
  *
  * Returns the size of the string INCLUDING the terminating NUL.
  * On exception, returns 0.
- * If the string is too long, returns a value greater than @n.
+ *
+ * If there is a limit on the length of a valid string, you may wish to
+ * consider using strnlen_user() instead.
  */
 static inline long strnlen_user(const char *s, long n)
 {
@@ -654,7 +771,7 @@
                "move\t%0, $2"
                : "=r" (res)
                : "r" (s), "r" (n)
-               : "$2", "$4", "$5", "$8", "$31");
+               : "$2", "$4", "$5", __UA_t0, "$31");
 
        return res;
 }
@@ -669,9 +786,9 @@
 extern unsigned long search_exception_table(unsigned long addr);
 
 /* Returns the new pc */
-#define fixup_exception(map_reg, fixup_unit, pc)                \
-({                                                              \
-       fixup_unit;                                             \
+#define fixup_exception(map_reg, fixup_unit, pc)                       \
+({                                                                     \
+       fixup_unit;                                                     \
 })
 
 #endif /* _ASM_UACCESS_H */


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