Resend: [PATCH] x86-64: fix unwind annotations in syscall stubs

Resend: [PATCH] x86-64: fix unwind annotations in syscall stubs

[Jan Beulich]

With the return address removed from the stack, these should really
refer to their caller's register state.

Signed-off-by: Jan Beulich <jbeulich@novell.com>

---
 arch/x86/kernel/entry_64.S |    7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

--- linux-2.6.36-rc3/arch/x86/kernel/entry_64.S
+++ 2.6.36-rc3-x86_64-stub-unwind-annotations/arch/x86/kernel/entry_64.S
@@ -714,9 +714,8 @@ END(ptregscall_common)
 
 ENTRY(stub_execve)
 	CFI_STARTPROC
-	popq %r11
-	CFI_ADJUST_CFA_OFFSET -8
-	CFI_REGISTER rip, r11
+	addq $8, %rsp
+	PARTIAL_FRAME 0
 	SAVE_REST
 	FIXUP_TOP_OF_STACK %r11
 	movq %rsp, %rcx
@@ -735,7 +734,7 @@ END(stub_execve)
 ENTRY(stub_rt_sigreturn)
 	CFI_STARTPROC
 	addq $8, %rsp
-	CFI_ADJUST_CFA_OFFSET	-8
+	PARTIAL_FRAME 0
 	SAVE_REST
 	movq %rsp,%rdi
 	FIXUP_TOP_OF_STACK %r11

Re: Resend: [PATCH] x86-64: fix unwind annotations in syscall stubs

[Alexander van Heukelum]

On Thu, 02 Sep 2010 13:52 +0100, "Jan Beulich" <JBeulich@novell.com> wrote:
> With the return address removed from the stack, these should really
> refer to their caller's register state.
> 
> Signed-off-by: Jan Beulich <jbeulich@novell.com>
> 
> ---
>  arch/x86/kernel/entry_64.S |    7 +++----
>  1 file changed, 3 insertions(+), 4 deletions(-)
> 
> --- linux-2.6.36-rc3/arch/x86/kernel/entry_64.S
> +++ 2.6.36-rc3-x86_64-stub-unwind-annotations/arch/x86/kernel/entry_64.S
> @@ -714,9 +714,8 @@ END(ptregscall_common)
>  
>  ENTRY(stub_execve)
>  	CFI_STARTPROC
> -       popq %r11
> -       CFI_ADJUST_CFA_OFFSET -8
> -       CFI_REGISTER rip, r11
> +       addq $8, %rsp
> +       PARTIAL_FRAME 0
>  	SAVE_REST
>  	FIXUP_TOP_OF_STACK %r11
>  	movq %rsp, %rcx
> @@ -735,7 +734,7 @@ END(stub_execve)
>  ENTRY(stub_rt_sigreturn)
>  	CFI_STARTPROC
>  	addq $8, %rsp
> -       CFI_ADJUST_CFA_OFFSET   -8
> +       PARTIAL_FRAME 0
>  	SAVE_REST
>  	movq %rsp,%rdi
>  	FIXUP_TOP_OF_STACK %r11
> 

Thanks for creating these...

Acked-by: Alexander van Heukelum <heukelum@fastmail.fm>

[tip:x86/debug] x86-64: Fix unwind annotations in syscall stubs

[tip-bot for Jan Beulich]

Commit-ID:  e6b04b6b5a3182ae36cf9a69f1aaaee432edc8ad
Gitweb:     http://git.kernel.org/tip/e6b04b6b5a3182ae36cf9a69f1aaaee432edc8ad
Author:     Jan Beulich <JBeulich@novell.com>
AuthorDate: Thu, 2 Sep 2010 13:52:45 +0100
Committer:  Ingo Molnar <mingo@elte.hu>
CommitDate: Fri, 3 Sep 2010 08:14:09 +0200

x86-64: Fix unwind annotations in syscall stubs

With the return address removed from the stack, these should
really refer to their caller's register state.

Signed-off-by: Jan Beulich <jbeulich@novell.com>
Acked-by: Alexander van Heukelum <heukelum@fastmail.fm>
LKML-Reference: <4C7FBA3D0200007800013F61@vpn.id2.novell.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
 arch/x86/kernel/entry_64.S |    9 ++++-----
 1 files changed, 4 insertions(+), 5 deletions(-)

diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S
index 17be5ec..16aeff0 100644
--- a/arch/x86/kernel/entry_64.S
+++ b/arch/x86/kernel/entry_64.S
@@ -714,9 +714,8 @@ END(ptregscall_common)
 
 ENTRY(stub_execve)
 	CFI_STARTPROC
-	popq %r11
-	CFI_ADJUST_CFA_OFFSET -8
-	CFI_REGISTER rip, r11
+	addq $8, %rsp
+	PARTIAL_FRAME 0
 	SAVE_REST
 	FIXUP_TOP_OF_STACK %r11
 	movq %rsp, %rcx
@@ -735,7 +734,7 @@ END(stub_execve)
 ENTRY(stub_rt_sigreturn)
 	CFI_STARTPROC
 	addq $8, %rsp
-	CFI_ADJUST_CFA_OFFSET	-8
+	PARTIAL_FRAME 0
 	SAVE_REST
 	movq %rsp,%rdi
 	FIXUP_TOP_OF_STACK %r11
@@ -1445,7 +1444,6 @@ error_swapgs:
 error_sti:
 	TRACE_IRQS_OFF
 	ret
-	CFI_ENDPROC
 
 /*
  * There are two places in the kernel that can potentially fault with
@@ -1470,6 +1468,7 @@ bstep_iret:
 	/* Fix truncated RIP */
 	movq %rcx,RIP+8(%rsp)
 	jmp error_swapgs
+	CFI_ENDPROC
 END(error_entry)