[PATCH] x86_64: Use a common function to find code segment bases

To avoid some code duplication.

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

2 files changed, 10 insertions, 7 deletions

diff --git a/arch/x86_64/mm/fault.c b/arch/x86_64/mm/fault.c
index d4676ca09144..e03309216764 100644
--- a/arch/x86_64/mm/fault.c
+++ b/arch/x86_64/mm/fault.c
@@ -62,21 +62,19 @@ void bust_spinlocks(int yes)
 static noinline int is_prefetch(struct pt_regs *regs, unsigned long addr,
                                 unsigned long error_code)
 { 
-        unsigned char *instr = (unsigned char *)(regs->rip);
+        unsigned char *instr;
         int scan_more = 1;
         int prefetch = 0; 
-        unsigned char *max_instr = instr + 15;
+        unsigned char *max_instr;
 
         /* If it was a exec fault ignore */
         if (error_code & (1<<4))
                 return 0;
         
-        /* Code segments in LDT could have a non zero base. Don't check
-           when that's possible */
-        if (regs->cs & (1<<2))
-                return 0;
+        instr = (unsigned char *)convert_rip_to_linear(current, regs);
+        max_instr = instr + 15;
 
-        if ((regs->cs & 3) != 0 && regs->rip >= TASK_SIZE)
+        if ((regs->cs & 3) != 0 && instr >= (unsigned char *)TASK_SIZE)
                 return 0;
 
         while (scan_more && instr < max_instr) { 
diff --git a/include/asm-x86_64/ptrace.h b/include/asm-x86_64/ptrace.h
index c7865cfedc1f..5bbc8d3141c8 100644
--- a/include/asm-x86_64/ptrace.h
+++ b/include/asm-x86_64/ptrace.h
@@ -86,6 +86,11 @@ struct pt_regs {
 extern unsigned long profile_pc(struct pt_regs *regs);
 void signal_fault(struct pt_regs *regs, void __user *frame, char *where);
 
+struct task_struct;
+
+extern unsigned long
+convert_rip_to_linear(struct task_struct *child, struct pt_regs *regs);
+
 enum {
         EF_CF   = 0x00000001,
         EF_PF   = 0x00000004,