x86: fix x86_32 stack protector bugs

[safe/jmp/linux-2.6] / arch / x86 / include / asm / system.h

diff --git a/arch/x86/include/asm/system.h b/arch/x86/include/asm/system.h
index 2692ee8..7a80f72 100644 (file)
--- a/arch/x86/include/asm/system.h
+++ b/arch/x86/include/asm/system.h
@@ -25,13 +25,11 @@ struct task_struct *__switch_to(struct task_struct *prev,
 
 #ifdef CONFIG_CC_STACKPROTECTOR
 #define __switch_canary                                                        \
-       "movl "__percpu_arg([current_task])",%%ebx\n\t"                 \
-       "movl %P[task_canary](%%ebx),%%ebx\n\t"                         \
-       "movl %%ebx,"__percpu_arg([stack_canary])"\n\t"
+       "movl %P[task_canary](%[next]), %%ebx\n\t"                      \
+       "movl %%ebx, "__percpu_arg([stack_canary])"\n\t"
 #define __switch_canary_oparam                                         \
        , [stack_canary] "=m" (per_cpu_var(stack_canary))
 #define __switch_canary_iparam                                         \
-       , [current_task] "m" (per_cpu_var(current_task))                \
        , [task_canary] "i" (offsetof(struct task_struct, stack_canary))
 #else  /* CC_STACKPROTECTOR */
 #define __switch_canary
@@ -60,9 +58,9 @@ do {                                                                  \
                     "movl %[next_sp],%%esp\n\t"        /* restore ESP   */ \
                     "movl $1f,%[prev_ip]\n\t"  /* save    EIP   */     \
                     "pushl %[next_ip]\n\t"     /* restore EIP   */     \
+                    __switch_canary                                    \
                     "jmp __switch_to\n"        /* regparm call  */     \
                     "1:\t"                                             \
-                    __switch_canary                                    \
                     "popl %%ebp\n\t"           /* restore EBP   */     \
                     "popfl\n"                  /* restore flags */     \
                                                                        \