From 464d1a78fbf8cf6c7fd970e7b3e2db50a320ce28 Mon Sep 17 00:00:00 2001 From: Jeremy Fitzhardinge Date: Tue, 13 Feb 2007 13:26:20 +0100 Subject: [PATCH] i386: Convert i386 PDA code to use %fs Convert the PDA code to use %fs rather than %gs as the segment for per-processor data. This is because some processors show a small but measurable performance gain for reloading a NULL segment selector (as %fs generally is in user-space) versus a non-NULL one (as %gs generally is). On modern processors the difference is very small, perhaps undetectable. Some old AMD "K6 3D+" processors are noticably slower when %fs is used rather than %gs; I have no idea why this might be, but I think they're sufficiently rare that it doesn't matter much. This patch also fixes the math emulator, which had not been adjusted to match the changed struct pt_regs. [frederik.deweerdt@gmail.com: fixit with gdb] [mingo@elte.hu: Fix KVM too] Signed-off-by: Jeremy Fitzhardinge Signed-off-by: Andi Kleen Cc: Ian Campbell Acked-by: Ingo Molnar Acked-by: Zachary Amsden Cc: Eric Dumazet Signed-off-by: Frederik Deweerdt Signed-off-by: Andrew Morton --- arch/i386/kernel/kprobes.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'arch/i386/kernel/kprobes.c') diff --git a/arch/i386/kernel/kprobes.c b/arch/i386/kernel/kprobes.c index af1d5334499..b85cfa3ce1d 100644 --- a/arch/i386/kernel/kprobes.c +++ b/arch/i386/kernel/kprobes.c @@ -363,7 +363,7 @@ no_kprobe: " pushf\n" /* skip cs, eip, orig_eax */ " subl $12, %esp\n" - " pushl %gs\n" + " pushl %fs\n" " pushl %ds\n" " pushl %es\n" " pushl %eax\n" @@ -387,7 +387,7 @@ no_kprobe: " popl %edi\n" " popl %ebp\n" " popl %eax\n" - /* skip eip, orig_eax, es, ds, gs */ + /* skip eip, orig_eax, es, ds, fs */ " addl $20, %esp\n" " popf\n" " ret\n"); -- cgit v1.2.3