Commit 42c24fa2 authored by Jeremy Fitzhardinge's avatar Jeremy Fitzhardinge Committed by Andi Kleen
Browse files

[PATCH] i386: PARAVIRT: Fix patch site clobbers to include return register 



Fix a few clobbers to include the return register.  The clobbers set
is the set of all registers modified (or may be modified) by the code
snippet, regardless of whether it was deliberate or accidental.

Also, make sure that callsites which are used in contexts which don't
allow clobbers actually save and restore all clobberable registers.

Signed-off-by: default avatarJeremy Fitzhardinge <jeremy@xensource.com>
Signed-off-by: default avatarAndi Kleen <ak@suse.de>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Zachary Amsden <zach@vmware.com>
parent d5822035

arch/i386/kernel/entry.S

+1 −1
Original line number Diff line number Diff line
@@ -338,7 +338,7 @@ sysenter_past_esp: 
	jae syscall_badsys

	call *sys_call_table(,%eax,4)

	movl %eax,PT_EAX(%esp)

	DISABLE_INTERRUPTS(CLBR_ECX|CLBR_EDX)

	DISABLE_INTERRUPTS(CLBR_ANY)

	TRACE_IRQS_OFF

	movl TI_flags(%ebp), %ecx

	testw $_TIF_ALLWORK_MASK, %cx

include/asm-i386/paravirt.h

+10 −8
Original line number Diff line number Diff line
@@ -535,7 +535,7 @@ static inline unsigned long __raw_local_save_flags(void) 
				  "popl %%edx; popl %%ecx")

		     : "=a"(f)

		     : paravirt_type(save_fl),

		       paravirt_clobber(CLBR_NONE)

		       paravirt_clobber(CLBR_EAX)

		     : "memory", "cc");

	return f;

}
@@ -620,27 +620,29 @@ static inline unsigned long __raw_local_irq_save(void) 
	.popsection



#define INTERRUPT_RETURN					\

	PARA_SITE(PARA_PATCH(PARAVIRT_iret), CLBR_ANY,		\

	PARA_SITE(PARA_PATCH(PARAVIRT_iret), CLBR_NONE,		\

		  jmp *%cs:paravirt_ops+PARAVIRT_iret)



#define DISABLE_INTERRUPTS(clobbers)					\

	PARA_SITE(PARA_PATCH(PARAVIRT_irq_disable), clobbers,		\

		  pushl %ecx; pushl %edx;				\

		  pushl %eax; pushl %ecx; pushl %edx;			\

		  call *%cs:paravirt_ops+PARAVIRT_irq_disable;		\

		  popl %edx; popl %ecx)					\

		  popl %edx; popl %ecx; popl %eax)			\



#define ENABLE_INTERRUPTS(clobbers)					\

	PARA_SITE(PARA_PATCH(PARAVIRT_irq_enable), clobbers,		\

		  pushl %ecx; pushl %edx;				\

		  pushl %eax; pushl %ecx; pushl %edx;			\

		  call *%cs:paravirt_ops+PARAVIRT_irq_enable;		\

		  popl %edx; popl %ecx)

		  popl %edx; popl %ecx; popl %eax)



#define ENABLE_INTERRUPTS_SYSEXIT					\

	PARA_SITE(PARA_PATCH(PARAVIRT_irq_enable_sysexit), CLBR_ANY,	\

	PARA_SITE(PARA_PATCH(PARAVIRT_irq_enable_sysexit), CLBR_NONE,	\

		  jmp *%cs:paravirt_ops+PARAVIRT_irq_enable_sysexit)



#define GET_CR0_INTO_EAX			\

	call *paravirt_ops+PARAVIRT_read_cr0

	push %ecx; push %edx;			\

	call *paravirt_ops+PARAVIRT_read_cr0;	\

	pop %edx; pop %ecx



#endif /* __ASSEMBLY__ */

#endif /* CONFIG_PARAVIRT */

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