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Commit 1de9c3f6 authored by Jan Beulich's avatar Jan Beulich Committed by Linus Torvalds
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[PATCH] x86_64: reliable stack trace support (x86-64 IRQ stack 



Change the switching to/from the IRQ stack so that unwind annotations can
be added for it without requiring CFA expressions.

AK: I cleaned it up a bit, making it unconditional and removing the
obsolete DEBUG_INFO full frame code.

Signed-off-by: default avatarJan Beulich <jbeulich@novell.com>
Signed-off-by: default avatarAndi Kleen <ak@suse.de>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent b538ed27

arch/x86_64/kernel/entry.S

+8 −25
Original line number Diff line number Diff line
@@ -473,29 +473,18 @@ END(stub_rt_sigreturn) 
/* 0(%rsp): interrupt number */ 

	.macro interrupt func

	cld

#ifdef CONFIG_DEBUG_INFO

	SAVE_ALL	

	movq %rsp,%rdi

	/*

	 * Setup a stack frame pointer.  This allows gdb to trace

	 * back to the original stack.

	 */

	movq %rsp,%rbp

	CFI_DEF_CFA_REGISTER	rbp

#else		

	SAVE_ARGS

	leaq -ARGOFFSET(%rsp),%rdi	# arg1 for handler

#endif	

	pushq %rbp

	CFI_ADJUST_CFA_OFFSET	8

	CFI_REL_OFFSET		rbp, 0

	movq %rsp,%rbp

	CFI_DEF_CFA_REGISTER	rbp

	testl $3,CS(%rdi)

	je 1f

	swapgs	

1:	incl	%gs:pda_irqcount	# RED-PEN should check preempt count

	movq %gs:pda_irqstackptr,%rax

	cmoveq %rax,%rsp /*todo This needs CFI annotation! */

	pushq %rdi			# save old stack	

#ifndef CONFIG_DEBUG_INFO

	CFI_ADJUST_CFA_OFFSET	8

#endif

	cmoveq %gs:pda_irqstackptr,%rsp

	call \func

	.endm
@@ -504,17 +493,11 @@ ENTRY(common_interrupt) 
	interrupt do_IRQ

	/* 0(%rsp): oldrsp-ARGOFFSET */

ret_from_intr:

	popq  %rdi

#ifndef CONFIG_DEBUG_INFO

	CFI_ADJUST_CFA_OFFSET	-8

#endif

	cli	

	decl %gs:pda_irqcount

#ifdef CONFIG_DEBUG_INFO

	movq RBP(%rdi),%rbp

	leaveq

	CFI_DEF_CFA_REGISTER	rsp

#endif

	leaq ARGOFFSET(%rdi),%rsp /*todo This needs CFI annotation! */

	CFI_ADJUST_CFA_OFFSET	-8

exit_intr:

	GET_THREAD_INFO(%rcx)

	testl $3,CS-ARGOFFSET(%rsp)