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x86/paravirt, 64-bit: don't restore user rsp within sysret

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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 <jeremy.fitzhardinge@citirx.com>
Cc: xen-devel <xen-devel@lists.xensource.com>
Cc: Stephen Tweedie <sct@redhat.com>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Cc: Mark McLoughlin <markmc@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Jeremy Fitzhardinge 2008-06-25 00:19:27 -04:00 committed by Ingo Molnar
parent d75cd22fdd
commit c7245da6ae
6 changed files with 14 additions and 15 deletions
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2
arch/x86/kernel/asm-offsets_64.c
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@ -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

6
arch/x86/kernel/entry_64.S
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@ -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 */

6
arch/x86/kernel/paravirt.c
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@ -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,

4
arch/x86/kernel/paravirt_patch_64.c
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@ -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);

3
include/asm-x86/irqflags.h
View File

@ -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

8
include/asm-x86/paravirt.h
View File

@ -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__ */