Re: [PATCH v12 07/21] x86/xen: Add stack frame dependency to hypercall inline asm calls

2015-09-09 Thread David Vrabel 
On 09/09/15 14:21, Josh Poimboeuf wrote:
> If a hypercall is inlined at the beginning of a function, gcc can insert
> the call instruction before setting up a stack frame, which breaks frame
> pointer convention if CONFIG_FRAME_POINTER is enabled and can result in
> a bad stack trace.
> 
> Force a stack frame to be created if CONFIG_FRAME_POINTER is enabled by
> listing the stack pointer as an output operand for the hypercall inline
> asm statements.

Reviewed-by: David Vrabel 

David
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[PATCH v12 07/21] x86/xen: Add stack frame dependency to hypercall inline asm calls

2015-09-09 Thread Josh Poimboeuf 
If a hypercall is inlined at the beginning of a function, gcc can insert
the call instruction before setting up a stack frame, which breaks frame
pointer convention if CONFIG_FRAME_POINTER is enabled and can result in
a bad stack trace.

Force a stack frame to be created if CONFIG_FRAME_POINTER is enabled by
listing the stack pointer as an output operand for the hypercall inline
asm statements.

Signed-off-by: Josh Poimboeuf 
Cc: Konrad Rzeszutek Wilk 
Cc: Boris Ostrovsky 
Cc: David Vrabel 
---
 arch/x86/include/asm/xen/hypercall.h | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/arch/x86/include/asm/xen/hypercall.h 
b/arch/x86/include/asm/xen/hypercall.h
index ca08a27..4488fbc 100644
--- a/arch/x86/include/asm/xen/hypercall.h
+++ b/arch/x86/include/asm/xen/hypercall.h
@@ -110,9 +110,10 @@ extern struct { char _entry[32]; } hypercall_page[];
register unsigned long __arg2 asm(__HYPERCALL_ARG2REG) = __arg2; \
register unsigned long __arg3 asm(__HYPERCALL_ARG3REG) = __arg3; \
register unsigned long __arg4 asm(__HYPERCALL_ARG4REG) = __arg4; \
-   register unsigned long __arg5 asm(__HYPERCALL_ARG5REG) = __arg5;
+   register unsigned long __arg5 asm(__HYPERCALL_ARG5REG) = __arg5; \
+   register void *__sp asm(_ASM_SP);
 
-#define __HYPERCALL_0PARAM "=r" (__res)
+#define __HYPERCALL_0PARAM "=r" (__res), "+r" (__sp)
 #define __HYPERCALL_1PARAM __HYPERCALL_0PARAM, "+r" (__arg1)
 #define __HYPERCALL_2PARAM __HYPERCALL_1PARAM, "+r" (__arg2)
 #define __HYPERCALL_3PARAM __HYPERCALL_2PARAM, "+r" (__arg3)
-- 
2.4.3

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Re: [PATCH v12 07/21] x86/xen: Add stack frame dependency to hypercall inline asm calls

2015-09-09 Thread David Vrabel 
On 09/09/15 14:21, Josh Poimboeuf wrote:
> If a hypercall is inlined at the beginning of a function, gcc can insert
> the call instruction before setting up a stack frame, which breaks frame
> pointer convention if CONFIG_FRAME_POINTER is enabled and can result in
> a bad stack trace.
> 
> Force a stack frame to be created if CONFIG_FRAME_POINTER is enabled by
> listing the stack pointer as an output operand for the hypercall inline
> asm statements.

Reviewed-by: David Vrabel 

David
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[PATCH v12 07/21] x86/xen: Add stack frame dependency to hypercall inline asm calls

2015-09-09 Thread Josh Poimboeuf 
If a hypercall is inlined at the beginning of a function, gcc can insert
the call instruction before setting up a stack frame, which breaks frame
pointer convention if CONFIG_FRAME_POINTER is enabled and can result in
a bad stack trace.

Force a stack frame to be created if CONFIG_FRAME_POINTER is enabled by
listing the stack pointer as an output operand for the hypercall inline
asm statements.

Signed-off-by: Josh Poimboeuf 
Cc: Konrad Rzeszutek Wilk 
Cc: Boris Ostrovsky 
Cc: David Vrabel 
---
 arch/x86/include/asm/xen/hypercall.h | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/arch/x86/include/asm/xen/hypercall.h 
b/arch/x86/include/asm/xen/hypercall.h
index ca08a27..4488fbc 100644
--- a/arch/x86/include/asm/xen/hypercall.h
+++ b/arch/x86/include/asm/xen/hypercall.h
@@ -110,9 +110,10 @@ extern struct { char _entry[32]; } hypercall_page[];
register unsigned long __arg2 asm(__HYPERCALL_ARG2REG) = __arg2; \
register unsigned long __arg3 asm(__HYPERCALL_ARG3REG) = __arg3; \
register unsigned long __arg4 asm(__HYPERCALL_ARG4REG) = __arg4; \
-   register unsigned long __arg5 asm(__HYPERCALL_ARG5REG) = __arg5;
+   register unsigned long __arg5 asm(__HYPERCALL_ARG5REG) = __arg5; \
+   register void *__sp asm(_ASM_SP);
 
-#define __HYPERCALL_0PARAM "=r" (__res)
+#define __HYPERCALL_0PARAM "=r" (__res), "+r" (__sp)
 #define __HYPERCALL_1PARAM __HYPERCALL_0PARAM, "+r" (__arg1)
 #define __HYPERCALL_2PARAM __HYPERCALL_1PARAM, "+r" (__arg2)
 #define __HYPERCALL_3PARAM __HYPERCALL_2PARAM, "+r" (__arg3)
-- 
2.4.3

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/