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 <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>

diff --git a/arch/x86/kernel/asm-offsets_64.c b/arch/x86/kernel/asm-offsets_64.c
index 27ac2deca465583870fc1c321ff398d2993b5d69..a19aba8c5bb3c5ea936b78c58b8483a19628aeda 100644 (file)
--- 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 0056bc4c61a9b22c1d713f2ea3b8924c792f00e3..18447a373fbd4aa8bf60b53d7627264379191245 100644 (file)
--- 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 565ee7a990ea85f3b63ac0b44624010fd3946865..b0b17f0bc7e9508b3dbd7b6749ce55872f001eac 100644 (file)
--- 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 4a170552b852924f5a896eb688defbf177915fc5..d4c0712a3e643c147478cfbcf97accc8912342c1 100644 (file)
--- 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 99ee5256a7e3b4d54c2bcf47f19f6f800ec9215c..544836c96b6134eb9a442349c0eab596926d7b1c 100644 (file)
--- 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 2668903b70f5e24d601b070d76fcf3905ab7a3ce..dad5b4186f51287e78a46fd03e95cb214399945f 100644 (file)
--- 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__ */