Commit f88cf230 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 

Pull x86 fix from Peter Anvin:
 "A single fix to not invoke the espfix code on Xen PV, as it turns out
  to oops the guest when invoked after all.  This patch leaves some
  amount of dead code, in particular unnecessary initialization of the
  espfix stacks when they won't be used, but in the interest of keeping
  the patch minimal that cleanup can wait for the next cycle"

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86_64/entry/xen: Do not invoke espfix64 on Xen
parents ecb679fc 7209a75d

arch/x86/include/asm/irqflags.h

+1 −1
Original line number Diff line number Diff line
@@ -129,7 +129,7 @@ static inline notrace unsigned long arch_local_irq_save(void) 


#define PARAVIRT_ADJUST_EXCEPTION_FRAME	/*  */



#define INTERRUPT_RETURN	iretq

#define INTERRUPT_RETURN	jmp native_iret

#define USERGS_SYSRET64				\

	swapgs;					\

	sysretq;

arch/x86/kernel/entry_64.S

+10 −18
Original line number Diff line number Diff line
@@ -830,27 +830,24 @@ restore_args: 
	RESTORE_ARGS 1,8,1



irq_return:

	INTERRUPT_RETURN



ENTRY(native_iret)

	/*

	 * Are we returning to a stack segment from the LDT?  Note: in

	 * 64-bit mode SS:RSP on the exception stack is always valid.

	 */

#ifdef CONFIG_X86_ESPFIX64

	testb $4,(SS-RIP)(%rsp)

	jnz irq_return_ldt

	jnz native_irq_return_ldt

#endif



irq_return_iret:

	INTERRUPT_RETURN

	_ASM_EXTABLE(irq_return_iret, bad_iret)



#ifdef CONFIG_PARAVIRT

ENTRY(native_iret)

native_irq_return_iret:

	iretq

	_ASM_EXTABLE(native_iret, bad_iret)

#endif

	_ASM_EXTABLE(native_irq_return_iret, bad_iret)



#ifdef CONFIG_X86_ESPFIX64

irq_return_ldt:

native_irq_return_ldt:

	pushq_cfi %rax

	pushq_cfi %rdi

	SWAPGS
@@ -872,7 +869,7 @@ irq_return_ldt: 
	SWAPGS

	movq %rax,%rsp

	popq_cfi %rax

	jmp irq_return_iret

	jmp native_irq_return_iret

#endif



	.section .fixup,"ax"
@@ -956,13 +953,8 @@ __do_double_fault: 
	cmpl $__KERNEL_CS,CS(%rdi)

	jne do_double_fault

	movq RIP(%rdi),%rax

	cmpq $irq_return_iret,%rax

#ifdef CONFIG_PARAVIRT

	je 1f

	cmpq $native_iret,%rax

#endif

	cmpq $native_irq_return_iret,%rax

	jne do_double_fault		/* This shouldn't happen... */

1:

	movq PER_CPU_VAR(kernel_stack),%rax

	subq $(6*8-KERNEL_STACK_OFFSET),%rax	/* Reset to original stack */

	movq %rax,RSP(%rdi)
@@ -1428,7 +1420,7 @@ error_sti: 
 */

error_kernelspace:

	incl %ebx

	leaq irq_return_iret(%rip),%rcx

	leaq native_irq_return_iret(%rip),%rcx

	cmpq %rcx,RIP+8(%rsp)

	je error_swapgs

	movl %ecx,%eax	/* zero extend */

arch/x86/kernel/paravirt_patch_64.c

+0 −2
Original line number Diff line number Diff line
@@ -6,7 +6,6 @@ DEF_NATIVE(pv_irq_ops, irq_disable, "cli"); 
DEF_NATIVE(pv_irq_ops, irq_enable, "sti");

DEF_NATIVE(pv_irq_ops, restore_fl, "pushq %rdi; popfq");

DEF_NATIVE(pv_irq_ops, save_fl, "pushfq; popq %rax");

DEF_NATIVE(pv_cpu_ops, iret, "iretq");

DEF_NATIVE(pv_mmu_ops, read_cr2, "movq %cr2, %rax");

DEF_NATIVE(pv_mmu_ops, read_cr3, "movq %cr3, %rax");

DEF_NATIVE(pv_mmu_ops, write_cr3, "movq %rdi, %cr3");
@@ -50,7 +49,6 @@ unsigned native_patch(u8 type, u16 clobbers, void *ibuf, 
		PATCH_SITE(pv_irq_ops, save_fl);

		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, irq_enable_sysexit);

		PATCH_SITE(pv_cpu_ops, usergs_sysret32);

		PATCH_SITE(pv_cpu_ops, usergs_sysret64);

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