x86: add %gs accessors for x86_32
Impact: cleanup
On x86_32, %gs is handled lazily. It's not saved and restored on
kernel entry/exit but only when necessary which usually is during task
switch but there are few other places. Currently, it's done by
calling savesegment() and loadsegment() explicitly. Define
get_user_gs(), set_user_gs() and task_user_gs() and use them instead.
While at it, clean up register access macros in signal.c.
This cleans up code a bit and will help future changes.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/arch/x86/math-emu/get_address.c b/arch/x86/math-emu/get_address.c
index 420b3b6..6ef5e99 100644
--- a/arch/x86/math-emu/get_address.c
+++ b/arch/x86/math-emu/get_address.c
@@ -150,11 +150,9 @@
#endif /* PARANOID */
switch (segment) {
- /* gs isn't used by the kernel, so it still has its
- user-space value. */
case PREFIX_GS_ - 1:
- /* N.B. - movl %seg, mem is a 2 byte write regardless of prefix */
- savesegment(gs, addr->selector);
+ /* user gs handling can be lazy, use special accessors */
+ addr->selector = get_user_gs(FPU_info->regs);
break;
default:
addr->selector = PM_REG_(segment);