x86, extable: Add _ASM_EXTABLE_EX() macro

Add _ASM_EXTABLE_EX() to generate the special extable entries that are
associated with uaccess_err.  This allows us to change the protocol
associated with these special entries.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Cc: David Daney <david.daney@cavium.com>
Link: http://lkml.kernel.org/r/CA%2B55aFyijf43qSu3N9nWHEBwaGbb7T2Oq9A=9EyR=Jtyqfq_cQ@mail.gmail.com

diff --git a/arch/x86/include/asm/asm.h b/arch/x86/include/asm/asm.h
index 53dce41f2517776917ea1b76312d0f3ee035d70d..0f15e8a4f565c72306ec20c638420a8292ed4fee 100644 (file)
--- a/arch/x86/include/asm/asm.h
+++ b/arch/x86/include/asm/asm.h
@@ -40,16 +40,28 @@
 
 /* Exception table entry */
 #ifdef __ASSEMBLY__
-# define _ASM_EXTABLE(from,to)                 \
-       .pushsection "__ex_table","a" ;         \
-       _ASM_ALIGN ;                            \
-       _ASM_PTR from , to ;                    \
+# define _ASM_EXTABLE(from,to)                                 \
+       .pushsection "__ex_table","a" ;                         \
+       _ASM_ALIGN ;                                            \
+       _ASM_PTR from , to ;                                    \
+       .popsection
+
+# define _ASM_EXTABLE_EX(from,to)                              \
+       .pushsection "__ex_table","a" ;                         \
+       _ASM_ALIGN ;                                            \
+       _ASM_PTR from , (to) - (from) ;                         \
        .popsection
 #else
-# define _ASM_EXTABLE(from,to)                 \
-       " .pushsection \"__ex_table\",\"a\"\n"  \
-       _ASM_ALIGN "\n"                         \
-       _ASM_PTR #from "," #to "\n"             \
+# define _ASM_EXTABLE(from,to)                                 \
+       " .pushsection \"__ex_table\",\"a\"\n"                  \
+       _ASM_ALIGN "\n"                                         \
+       _ASM_PTR #from "," #to "\n"                             \
+       " .popsection\n"
+
+# define _ASM_EXTABLE_EX(from,to)                              \
+       " .pushsection \"__ex_table\",\"a\"\n"                  \
+       _ASM_ALIGN "\n"                                         \
+       _ASM_PTR #from ",(" #to ")-(" #from ")\n"               \
        " .popsection\n"
 #endif
 

diff --git a/arch/x86/include/asm/uaccess.h b/arch/x86/include/asm/uaccess.h
index e0544597cfe7b30a0e40d52c9d13cb65a6bf3d6c..4ee59dd66f5ddbecf4aaeea50fbfab62968fd04a 100644 (file)
--- a/arch/x86/include/asm/uaccess.h
+++ b/arch/x86/include/asm/uaccess.h
@@ -202,8 +202,8 @@ extern int __get_user_bad(void);
        asm volatile("1:        movl %%eax,0(%1)\n"                     \
                     "2:        movl %%edx,4(%1)\n"                     \
                     "3:\n"                                             \
-                    _ASM_EXTABLE(1b, 2b - 1b)                          \
-                    _ASM_EXTABLE(2b, 3b - 2b)                          \
+                    _ASM_EXTABLE_EX(1b, 2b)                            \
+                    _ASM_EXTABLE_EX(2b, 3b)                            \
                     : : "A" (x), "r" (addr))
 
 #define __put_user_x8(x, ptr, __ret_pu)                                \
@@ -408,7 +408,7 @@ do {                                                                        \
 #define __get_user_asm_ex(x, addr, itype, rtype, ltype)                        \
        asm volatile("1:        mov"itype" %1,%"rtype"0\n"              \
                     "2:\n"                                             \
-                    _ASM_EXTABLE(1b, 2b - 1b)                          \
+                    _ASM_EXTABLE_EX(1b, 2b)                            \
                     : ltype(x) : "m" (__m(addr)))
 
 #define __put_user_nocheck(x, ptr, size)                       \
@@ -450,7 +450,7 @@ struct __large_struct { unsigned long buf[100]; };
 #define __put_user_asm_ex(x, addr, itype, rtype, ltype)                        \
        asm volatile("1:        mov"itype" %"rtype"0,%1\n"              \
                     "2:\n"                                             \
-                    _ASM_EXTABLE(1b, 2b - 1b)                          \
+                    _ASM_EXTABLE_EX(1b, 2b)                            \
                     : : ltype(x), "m" (__m(addr)))
 
 /*