From: Jeremy Fitzhardinge Date: Wed, 25 Jun 2008 04:19:27 +0000 (-0400) Subject: x86/paravirt, 64-bit: don't restore user rsp within sysret X-Git-Tag: v2.6.27-rc1~1106^2~125 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=c7245da6ae7e5208504ff027c4e0eec69b788651;p=linux-2.6 x86/paravirt, 64-bit: don't restore user rsp within sysret There's no need to combine restoring the user rsp within the sysret pvop, so split it out. This makes the pvop's semantics closer to the machine instruction. Signed-off-by: Jeremy Fitzhardinge Cc: xen-devel Cc: Stephen Tweedie Cc: Eduardo Habkost Cc: Mark McLoughlin Signed-off-by: Ingo Molnar --- diff --git a/arch/x86/kernel/asm-offsets_64.c b/arch/x86/kernel/asm-offsets_64.c index 27ac2deca4..a19aba8c5b 100644 --- a/arch/x86/kernel/asm-offsets_64.c +++ b/arch/x86/kernel/asm-offsets_64.c @@ -62,7 +62,7 @@ int main(void) OFFSET(PV_IRQ_irq_disable, pv_irq_ops, irq_disable); OFFSET(PV_IRQ_irq_enable, pv_irq_ops, irq_enable); OFFSET(PV_CPU_iret, pv_cpu_ops, iret); - OFFSET(PV_CPU_usersp_sysret, pv_cpu_ops, usersp_sysret); + OFFSET(PV_CPU_usergs_sysret, pv_cpu_ops, usergs_sysret); OFFSET(PV_CPU_swapgs, pv_cpu_ops, swapgs); OFFSET(PV_MMU_read_cr2, pv_mmu_ops, read_cr2); #endif diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S index 0056bc4c61..18447a373f 100644 --- a/arch/x86/kernel/entry_64.S +++ b/arch/x86/kernel/entry_64.S @@ -59,8 +59,7 @@ #endif #ifdef CONFIG_PARAVIRT -ENTRY(native_usersp_sysret) - movq %gs:pda_oldrsp,%rsp +ENTRY(native_usergs_sysret) swapgs sysretq #endif /* CONFIG_PARAVIRT */ @@ -275,7 +274,8 @@ sysret_check: CFI_REGISTER rip,rcx RESTORE_ARGS 0,-ARG_SKIP,1 /*CFI_REGISTER rflags,r11*/ - USERSP_SYSRET + movq %gs:pda_oldrsp, %rsp + USERGS_SYSRET CFI_RESTORE_STATE /* Handle reschedules */ diff --git a/arch/x86/kernel/paravirt.c b/arch/x86/kernel/paravirt.c index 565ee7a990..b0b17f0bc7 100644 --- a/arch/x86/kernel/paravirt.c +++ b/arch/x86/kernel/paravirt.c @@ -141,7 +141,7 @@ unsigned paravirt_patch_default(u8 type, u16 clobbers, void *insnbuf, ret = paravirt_patch_nop(); else if (type == PARAVIRT_PATCH(pv_cpu_ops.iret) || type == PARAVIRT_PATCH(pv_cpu_ops.irq_enable_sysexit) || - type == PARAVIRT_PATCH(pv_cpu_ops.usersp_sysret)) + type == PARAVIRT_PATCH(pv_cpu_ops.usergs_sysret)) /* If operation requires a jmp, then jmp */ ret = paravirt_patch_jmp(insnbuf, opfunc, addr, len); else @@ -193,7 +193,7 @@ static void native_flush_tlb_single(unsigned long addr) /* These are in entry.S */ extern void native_iret(void); extern void native_irq_enable_sysexit(void); -extern void native_usersp_sysret(void); +extern void native_usergs_sysret(void); static int __init print_banner(void) { @@ -332,7 +332,7 @@ struct pv_cpu_ops pv_cpu_ops = { #ifdef CONFIG_X86_32 .irq_enable_sysexit = native_irq_enable_sysexit, #else - .usersp_sysret = native_usersp_sysret, + .usergs_sysret = native_usergs_sysret, #endif .iret = native_iret, .swapgs = native_swapgs, diff --git a/arch/x86/kernel/paravirt_patch_64.c b/arch/x86/kernel/paravirt_patch_64.c index 4a170552b8..d4c0712a3e 100644 --- a/arch/x86/kernel/paravirt_patch_64.c +++ b/arch/x86/kernel/paravirt_patch_64.c @@ -15,7 +15,7 @@ DEF_NATIVE(pv_cpu_ops, clts, "clts"); DEF_NATIVE(pv_cpu_ops, wbinvd, "wbinvd"); /* the three commands give us more control to how to return from a syscall */ -DEF_NATIVE(pv_cpu_ops, usersp_sysret, "movq %gs:" __stringify(pda_oldrsp) ", %rsp; swapgs; sysretq;"); +DEF_NATIVE(pv_cpu_ops, usergs_sysret, "swapgs; sysretq;"); DEF_NATIVE(pv_cpu_ops, swapgs, "swapgs"); unsigned native_patch(u8 type, u16 clobbers, void *ibuf, @@ -35,7 +35,7 @@ unsigned native_patch(u8 type, u16 clobbers, void *ibuf, PATCH_SITE(pv_irq_ops, irq_enable); PATCH_SITE(pv_irq_ops, irq_disable); PATCH_SITE(pv_cpu_ops, iret); - PATCH_SITE(pv_cpu_ops, usersp_sysret); + PATCH_SITE(pv_cpu_ops, usergs_sysret); PATCH_SITE(pv_cpu_ops, swapgs); PATCH_SITE(pv_mmu_ops, read_cr2); PATCH_SITE(pv_mmu_ops, read_cr3); diff --git a/include/asm-x86/irqflags.h b/include/asm-x86/irqflags.h index 99ee5256a7..544836c96b 100644 --- a/include/asm-x86/irqflags.h +++ b/include/asm-x86/irqflags.h @@ -112,8 +112,7 @@ static inline unsigned long __raw_local_irq_save(void) #ifdef CONFIG_X86_64 #define INTERRUPT_RETURN iretq -#define USERSP_SYSRET \ - movq %gs:pda_oldrsp, %rsp; \ +#define USERGS_SYSRET \ swapgs; \ sysretq; #else diff --git a/include/asm-x86/paravirt.h b/include/asm-x86/paravirt.h index 2668903b70..dad5b4186f 100644 --- a/include/asm-x86/paravirt.h +++ b/include/asm-x86/paravirt.h @@ -143,7 +143,7 @@ struct pv_cpu_ops { /* These three are jmp to, not actually called. */ void (*irq_enable_sysexit)(void); - void (*usersp_sysret)(void); + void (*usergs_sysret)(void); void (*iret)(void); void (*swapgs)(void); @@ -1505,10 +1505,10 @@ static inline unsigned long __raw_local_irq_save(void) movq %rax, %rcx; \ xorq %rax, %rax; -#define USERSP_SYSRET \ - PARA_SITE(PARA_PATCH(pv_cpu_ops, PV_CPU_usersp_sysret), \ +#define USERGS_SYSRET \ + PARA_SITE(PARA_PATCH(pv_cpu_ops, PV_CPU_usergs_sysret), \ CLBR_NONE, \ - jmp PARA_INDIRECT(pv_cpu_ops+PV_CPU_usersp_sysret)) + jmp PARA_INDIRECT(pv_cpu_ops+PV_CPU_usergs_sysret)) #endif #endif /* __ASSEMBLY__ */