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authorTejun Heo <tj@kernel.org>2009-02-09 22:17:40 +0900
committerIngo Molnar <mingo@elte.hu>2009-02-10 00:41:58 +0100
commitd9a89a26e02ef9ed03f74a755a8b4d8f3a066622 (patch)
tree35f3713bca4e6b815f6b9db92dc9d812ec7213ff /arch/x86/include/asm/system.h
parentf0d96110f9fd98a1a22e03b8adba69508843d910 (diff)
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>
Diffstat (limited to 'arch/x86/include/asm/system.h')
-rw-r--r--arch/x86/include/asm/system.h9
1 files changed, 9 insertions, 0 deletions
diff --git a/arch/x86/include/asm/system.h b/arch/x86/include/asm/system.h
index 2fcc70bc85f3..70c74b8db875 100644
--- a/arch/x86/include/asm/system.h
+++ b/arch/x86/include/asm/system.h
@@ -182,6 +182,15 @@ extern void native_load_gs_index(unsigned);
#define savesegment(seg, value) \
asm("mov %%" #seg ",%0":"=r" (value) : : "memory")
+/*
+ * x86_32 user gs accessors.
+ */
+#ifdef CONFIG_X86_32
+#define get_user_gs(regs) (u16)({unsigned long v; savesegment(gs, v); v;})
+#define set_user_gs(regs, v) loadsegment(gs, (unsigned long)(v))
+#define task_user_gs(tsk) ((tsk)->thread.gs)
+#endif
+
static inline unsigned long get_limit(unsigned long segment)
{
unsigned long __limit;