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Commit c7245da6 authored by Jeremy Fitzhardinge's avatar Jeremy Fitzhardinge Committed by Ingo Molnar
Browse files

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: default avatarJeremy 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: default avatarIngo Molnar <mingo@elte.hu>
parent d75cd22f

arch/x86/kernel/asm-offsets_64.c

+1 −1
Original line number Diff line number Diff line
@@ -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

arch/x86/kernel/entry_64.S

+3 −3
Original line number Diff line number Diff line
@@ -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 */

arch/x86/kernel/paravirt.c

+3 −3
Original line number Diff line number Diff line
@@ -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,

arch/x86/kernel/paravirt_patch_64.c

+2 −2
Original line number Diff line number Diff line
@@ -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);

include/asm-x86/irqflags.h

+1 −2
Original line number Diff line number Diff line
@@ -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