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 --- include/asm-i386/elf.h | 4 ++-- include/asm-i386/mmu_context.h | 2 +- include/asm-i386/pda.h | 12 ++++++------ include/asm-i386/processor.h | 6 +++--- include/asm-i386/ptrace.h | 4 ++-- 5 files changed, 14 insertions(+), 14 deletions(-) (limited to 'include') diff --git a/include/asm-i386/elf.h b/include/asm-i386/elf.h index 369035dfe4b..8d33c9bb7c1 100644 --- a/include/asm-i386/elf.h +++ b/include/asm-i386/elf.h @@ -90,8 +90,8 @@ typedef struct user_fxsr_struct elf_fpxregset_t; pr_reg[6] = regs->eax; \ pr_reg[7] = regs->xds; \ pr_reg[8] = regs->xes; \ - savesegment(fs,pr_reg[9]); \ - pr_reg[10] = regs->xgs; \ + pr_reg[9] = regs->xfs; \ + savesegment(gs,pr_reg[10]); \ pr_reg[11] = regs->orig_eax; \ pr_reg[12] = regs->eip; \ pr_reg[13] = regs->xcs; \ diff --git a/include/asm-i386/mmu_context.h b/include/asm-i386/mmu_context.h index 68ff102d6f5..e6aa30f8de5 100644 --- a/include/asm-i386/mmu_context.h +++ b/include/asm-i386/mmu_context.h @@ -63,7 +63,7 @@ static inline void switch_mm(struct mm_struct *prev, } #define deactivate_mm(tsk, mm) \ - asm("movl %0,%%fs": :"r" (0)); + asm("movl %0,%%gs": :"r" (0)); #define activate_mm(prev, next) \ switch_mm((prev),(next),NULL) diff --git a/include/asm-i386/pda.h b/include/asm-i386/pda.h index 2ba2736aa10..b12d59a318b 100644 --- a/include/asm-i386/pda.h +++ b/include/asm-i386/pda.h @@ -39,19 +39,19 @@ extern struct i386_pda _proxy_pda; if (0) { T__ tmp__; tmp__ = (val); } \ switch (sizeof(_proxy_pda.field)) { \ case 1: \ - asm(op "b %1,%%gs:%c2" \ + asm(op "b %1,%%fs:%c2" \ : "+m" (_proxy_pda.field) \ :"ri" ((T__)val), \ "i"(pda_offset(field))); \ break; \ case 2: \ - asm(op "w %1,%%gs:%c2" \ + asm(op "w %1,%%fs:%c2" \ : "+m" (_proxy_pda.field) \ :"ri" ((T__)val), \ "i"(pda_offset(field))); \ break; \ case 4: \ - asm(op "l %1,%%gs:%c2" \ + asm(op "l %1,%%fs:%c2" \ : "+m" (_proxy_pda.field) \ :"ri" ((T__)val), \ "i"(pda_offset(field))); \ @@ -65,19 +65,19 @@ extern struct i386_pda _proxy_pda; typeof(_proxy_pda.field) ret__; \ switch (sizeof(_proxy_pda.field)) { \ case 1: \ - asm(op "b %%gs:%c1,%0" \ + asm(op "b %%fs:%c1,%0" \ : "=r" (ret__) \ : "i" (pda_offset(field)), \ "m" (_proxy_pda.field)); \ break; \ case 2: \ - asm(op "w %%gs:%c1,%0" \ + asm(op "w %%fs:%c1,%0" \ : "=r" (ret__) \ : "i" (pda_offset(field)), \ "m" (_proxy_pda.field)); \ break; \ case 4: \ - asm(op "l %%gs:%c1,%0" \ + asm(op "l %%fs:%c1,%0" \ : "=r" (ret__) \ : "i" (pda_offset(field)), \ "m" (_proxy_pda.field)); \ diff --git a/include/asm-i386/processor.h b/include/asm-i386/processor.h index 359f10b54f5..11bf899de8a 100644 --- a/include/asm-i386/processor.h +++ b/include/asm-i386/processor.h @@ -424,7 +424,7 @@ struct thread_struct { .vm86_info = NULL, \ .sysenter_cs = __KERNEL_CS, \ .io_bitmap_ptr = NULL, \ - .gs = __KERNEL_PDA, \ + .fs = __KERNEL_PDA, \ } /* @@ -442,8 +442,8 @@ struct thread_struct { } #define start_thread(regs, new_eip, new_esp) do { \ - __asm__("movl %0,%%fs": :"r" (0)); \ - regs->xgs = 0; \ + __asm__("movl %0,%%gs": :"r" (0)); \ + regs->xfs = 0; \ set_fs(USER_DS); \ regs->xds = __USER_DS; \ regs->xes = __USER_DS; \ diff --git a/include/asm-i386/ptrace.h b/include/asm-i386/ptrace.h index bdbc894339b..1646996c73d 100644 --- a/include/asm-i386/ptrace.h +++ b/include/asm-i386/ptrace.h @@ -16,8 +16,8 @@ struct pt_regs { long eax; int xds; int xes; - /* int xfs; */ - int xgs; + int xfs; + /* int xgs; */ long orig_eax; long eip; int xcs; -- cgit v1.2.3