[PATCH] i386: Fix places where using %gs changes the usermode ABI

There are a few places where the change in struct pt_regs and the use of %gs
affect the userspace ABI.  These are primarily debugging interfaces where
thread state can be inspected or extracted.

Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Cc: Chuck Ebbert <76306.1226@compuserve.com>
Cc: Zachary Amsden <zach@vmware.com>
Cc: Jan Beulich <jbeulich@novell.com>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>

2 files changed, 2 insertions, 1 deletions

diff --git a/include/asm-i386/elf.h b/include/asm-i386/elf.h
index 3a05436f31c0..45d21a0c95bf 100644
--- a/include/asm-i386/elf.h
+++ b/include/asm-i386/elf.h
@@ -91,7 +91,7 @@ typedef struct user_fxsr_struct elf_fpxregset_t;
         pr_reg[7] = regs->xds;                          \
         pr_reg[8] = regs->xes;                          \
         savesegment(fs,pr_reg[9]);                      \
-        savesegment(gs,pr_reg[10]);                     \
+        pr_reg[10] = regs->xgs;                         \
         pr_reg[11] = regs->orig_eax;                    \
         pr_reg[12] = regs->eip;                         \
         pr_reg[13] = regs->xcs;                         \
diff --git a/include/asm-i386/unwind.h b/include/asm-i386/unwind.h
index 5031d693b89d..601fc67bd775 100644
--- a/include/asm-i386/unwind.h
+++ b/include/asm-i386/unwind.h
@@ -71,6 +71,7 @@ static inline void arch_unw_init_blocked(struct unwind_frame_info *info)
         info->regs.xss = __KERNEL_DS;
         info->regs.xds = __USER_DS;
         info->regs.xes = __USER_DS;
+        info->regs.xgs = __KERNEL_PDA;
 }
 
 extern asmlinkage int arch_unwind_init_running(struct unwind_frame_info *,