[PATCH 31 of 36] x86_64 pvops: don't restore user rsp within sysret

Jeremy Fitzhardinge
2008-06-25T04:47:17Z

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>
---
arch/x86/kernel/asm-offsets_64.c | 2 +-
arch/x86/kernel/entry_64.S | 6 +++---
arch/x86/kernel/paravirt.c | 6 +++---
arch/x86/kernel/paravirt_patch_64.c | 4 ++--
include/asm-x86/irqflags.h | 3 +--
include/asm-x86/paravirt.h | 8 ++++----
6 files changed, 14 insertions(+), 15 deletions(-)

diff --git a/arch/x86/kernel/asm-offsets_64.c b/arch/x86/kernel/asm-offsets_64.c
--- a/arch/x86/kernel/asm-offsets_64.c
+++ b/arch/x86/kernel/asm-offsets_64.c
@@ -63,7 +63,7 @@
OFFSET(PV_IRQ_irq_enable, pv_irq_ops, irq_enable);
OFFSET(PV_CPU_iret, pv_cpu_ops, iret);
OFFSET(PV_CPU_nmi_return, pv_cpu_ops, nmi_return);
- 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
--- a/arch/x86/kernel/entry_64.S
+++ b/arch/x86/kernel/entry_64.S
@@ -167,8 +167,7 @@
#endif

#ifdef CONFIG_PARAVIRT
-ENTRY(native_usersp_sysret)
- movq %gs:pda_oldrsp,%rsp
+ENTRY(native_usergs_sysret)
swapgs
sysretq
#endif /* CONFIG_PARAVIRT */
@@ -383,7 +382,8 @@
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
--- a/arch/x86/kernel/paravirt.c
+++ b/arch/x86/kernel/paravirt.c
@@ -142,7 +142,7 @@
else if (type == PARAVIRT_PATCH(pv_cpu_ops.iret) ||
type == PARAVIRT_PATCH(pv_cpu_ops.nmi_return) ||
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
@@ -195,7 +195,7 @@
extern void native_iret(void);
extern void native_nmi_return(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)
{
@@ -334,7 +334,7 @@
#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,
.nmi_return = native_nmi_return,
diff --git a/arch/x86/kernel/paravirt_patch_64.c b/arch/x86/kernel/paravirt_patch_64.c
--- a/arch/x86/kernel/paravirt_patch_64.c
+++ b/arch/x86/kernel/paravirt_patch_64.c
@@ -18,7 +18,7 @@
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,
@@ -39,7 +39,7 @@
PATCH_SITE(pv_irq_ops, irq_disable);
PATCH_SITE(pv_cpu_ops, iret);
PATCH_SITE(pv_cpu_ops, nmi_return);
- 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
--- a/include/asm-x86/irqflags.h
+++ b/include/asm-x86/irqflags.h
@@ -168,8 +168,7 @@

#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
--- a/include/asm-x86/paravirt.h
+++ b/include/asm-x86/paravirt.h
@@ -143,7 +143,7 @@

/* These ones are jmp'ed to, not actually called. */
void (*irq_enable_sysexit)(void);
- void (*usersp_sysret)(void);
+ void (*usergs_sysret)(void);
void (*iret)(void);
void (*nmi_return)(void);

@@ -1510,10 +1510,10 @@
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__ */