diff mbox series

[RFC,v5,47/57] arm64: assembler: Add macro to annotate asm function having non standard stack-frame.

Message ID 20200109160300.26150-48-jthierry@redhat.com (mailing list archive)
State New, archived
Headers show
Series objtool: Add support for arm64 | expand

Commit Message

Julien Thierry Jan. 9, 2020, 4:02 p.m. UTC
From: Raphael Gault <raphael.gault@arm.com>

Some functions don't have standard stack-frames but are intended
this way. In order for objtool to ignore those particular cases
we add a macro that enables us to annotate the cases we chose
to mark as particular.

Signed-off-by: Raphael Gault <raphael.gault@arm.com>
Signed-off-by: Julien Thierry <jthierry@redhat.com>
---
 include/linux/frame.h | 19 ++++++++++++++++++-
 1 file changed, 18 insertions(+), 1 deletion(-)

--
2.21.0

Comments

Will Deacon Jan. 21, 2020, 10:30 a.m. UTC | #1
On Thu, Jan 09, 2020 at 04:02:50PM +0000, Julien Thierry wrote:
> From: Raphael Gault <raphael.gault@arm.com>
> 
> Some functions don't have standard stack-frames but are intended
> this way. In order for objtool to ignore those particular cases
> we add a macro that enables us to annotate the cases we chose
> to mark as particular.
> 
> Signed-off-by: Raphael Gault <raphael.gault@arm.com>
> Signed-off-by: Julien Thierry <jthierry@redhat.com>
> ---
>  include/linux/frame.h | 19 ++++++++++++++++++-
>  1 file changed, 18 insertions(+), 1 deletion(-)
> 
> diff --git a/include/linux/frame.h b/include/linux/frame.h
> index 02d3ca2d9598..1e35e58ab259 100644
> --- a/include/linux/frame.h
> +++ b/include/linux/frame.h
> @@ -11,14 +11,31 @@
>   *
>   * For more information, see tools/objtool/Documentation/stack-validation.txt.
>   */
> +#ifndef __ASSEMBLY__
>  #define STACK_FRAME_NON_STANDARD(func) \
>  	static void __used __section(.discard.func_stack_frame_non_standard) \
>  		*__func_stack_frame_non_standard_##func = func
> +#else
> +	/*
> +	 * This macro is the arm64 assembler equivalent of the
> +	 * macro STACK_FRAME_NON_STANDARD define at
> +	 * ~/include/linux/frame.h
> +	 */
> +	.macro	asm_stack_frame_non_standard	func
> +	.pushsection ".discard.func_stack_frame_non_standard"
> +	.quad	\func
> +	.popsection
> +	.endm
> 
> +#endif /* __ASSEMBLY__ */
>  #else /* !CONFIG_STACK_VALIDATION */
> 
> +#ifndef __ASSEMBLY__
>  #define STACK_FRAME_NON_STANDARD(func)
> -
> +#else
> +	.macro	asm_stack_frame_non_standard	func
> +	.endm
> +#endif /* __ASSEMBLY__ */

Hmm. Given that we're currently going through the exercise of converting
a bunch of ENTRY/ENDPROC macros to use the new SYM_{CODE,FUNC}_{START,END}
macros, I would much prefer for this to be a new flavour of those.

In fact, can you just use SYM_CODE_* for this?

Will
Julien Thierry Jan. 23, 2020, 1:45 p.m. UTC | #2
On 1/21/20 10:30 AM, Will Deacon wrote:
> On Thu, Jan 09, 2020 at 04:02:50PM +0000, Julien Thierry wrote:
>> From: Raphael Gault <raphael.gault@arm.com>
>>
>> Some functions don't have standard stack-frames but are intended
>> this way. In order for objtool to ignore those particular cases
>> we add a macro that enables us to annotate the cases we chose
>> to mark as particular.
>>
>> Signed-off-by: Raphael Gault <raphael.gault@arm.com>
>> Signed-off-by: Julien Thierry <jthierry@redhat.com>
>> ---
>>   include/linux/frame.h | 19 ++++++++++++++++++-
>>   1 file changed, 18 insertions(+), 1 deletion(-)
>>
>> diff --git a/include/linux/frame.h b/include/linux/frame.h
>> index 02d3ca2d9598..1e35e58ab259 100644
>> --- a/include/linux/frame.h
>> +++ b/include/linux/frame.h
>> @@ -11,14 +11,31 @@
>>    *
>>    * For more information, see tools/objtool/Documentation/stack-validation.txt.
>>    */
>> +#ifndef __ASSEMBLY__
>>   #define STACK_FRAME_NON_STANDARD(func) \
>>   	static void __used __section(.discard.func_stack_frame_non_standard) \
>>   		*__func_stack_frame_non_standard_##func = func
>> +#else
>> +	/*
>> +	 * This macro is the arm64 assembler equivalent of the
>> +	 * macro STACK_FRAME_NON_STANDARD define at
>> +	 * ~/include/linux/frame.h
>> +	 */
>> +	.macro	asm_stack_frame_non_standard	func
>> +	.pushsection ".discard.func_stack_frame_non_standard"
>> +	.quad	\func
>> +	.popsection
>> +	.endm
>>
>> +#endif /* __ASSEMBLY__ */
>>   #else /* !CONFIG_STACK_VALIDATION */
>>
>> +#ifndef __ASSEMBLY__
>>   #define STACK_FRAME_NON_STANDARD(func)
>> -
>> +#else
>> +	.macro	asm_stack_frame_non_standard	func
>> +	.endm
>> +#endif /* __ASSEMBLY__ */
> 
> Hmm. Given that we're currently going through the exercise of converting
> a bunch of ENTRY/ENDPROC macros to use the new SYM_{CODE,FUNC}_{START,END}
> macros, I would much prefer for this to be a new flavour of those.
> 
> In fact, can you just use SYM_CODE_* for this?
> 

You mean to not introduce the STACK_FRAME_NON_STANDARD() macro and just 
mark the asm callable symbols that don't set up a stackframe as SYM_CODE_* ?
Will Deacon Jan. 23, 2020, 2:40 p.m. UTC | #3
On Thu, Jan 23, 2020 at 01:45:58PM +0000, Julien Thierry wrote:
> On 1/21/20 10:30 AM, Will Deacon wrote:
> > On Thu, Jan 09, 2020 at 04:02:50PM +0000, Julien Thierry wrote:
> > > From: Raphael Gault <raphael.gault@arm.com>
> > > diff --git a/include/linux/frame.h b/include/linux/frame.h
> > > index 02d3ca2d9598..1e35e58ab259 100644
> > > --- a/include/linux/frame.h
> > > +++ b/include/linux/frame.h
> > > @@ -11,14 +11,31 @@
> > >    *
> > >    * For more information, see tools/objtool/Documentation/stack-validation.txt.
> > >    */
> > > +#ifndef __ASSEMBLY__
> > >   #define STACK_FRAME_NON_STANDARD(func) \
> > >   	static void __used __section(.discard.func_stack_frame_non_standard) \
> > >   		*__func_stack_frame_non_standard_##func = func
> > > +#else
> > > +	/*
> > > +	 * This macro is the arm64 assembler equivalent of the
> > > +	 * macro STACK_FRAME_NON_STANDARD define at
> > > +	 * ~/include/linux/frame.h
> > > +	 */
> > > +	.macro	asm_stack_frame_non_standard	func
> > > +	.pushsection ".discard.func_stack_frame_non_standard"
> > > +	.quad	\func
> > > +	.popsection
> > > +	.endm
> > > 
> > > +#endif /* __ASSEMBLY__ */
> > >   #else /* !CONFIG_STACK_VALIDATION */
> > > 
> > > +#ifndef __ASSEMBLY__
> > >   #define STACK_FRAME_NON_STANDARD(func)
> > > -
> > > +#else
> > > +	.macro	asm_stack_frame_non_standard	func
> > > +	.endm
> > > +#endif /* __ASSEMBLY__ */
> > 
> > Hmm. Given that we're currently going through the exercise of converting
> > a bunch of ENTRY/ENDPROC macros to use the new SYM_{CODE,FUNC}_{START,END}
> > macros, I would much prefer for this to be a new flavour of those.
> > 
> > In fact, can you just use SYM_CODE_* for this?
> > 
> 
> You mean to not introduce the STACK_FRAME_NON_STANDARD() macro and just mark
> the asm callable symbols that don't set up a stackframe as SYM_CODE_* ?

Yes, unless I'm mistaken, SYM_CODE_* is intended for that sort of thing
anyway.

Will
diff mbox series

Patch

diff --git a/include/linux/frame.h b/include/linux/frame.h
index 02d3ca2d9598..1e35e58ab259 100644
--- a/include/linux/frame.h
+++ b/include/linux/frame.h
@@ -11,14 +11,31 @@ 
  *
  * For more information, see tools/objtool/Documentation/stack-validation.txt.
  */
+#ifndef __ASSEMBLY__
 #define STACK_FRAME_NON_STANDARD(func) \
 	static void __used __section(.discard.func_stack_frame_non_standard) \
 		*__func_stack_frame_non_standard_##func = func
+#else
+	/*
+	 * This macro is the arm64 assembler equivalent of the
+	 * macro STACK_FRAME_NON_STANDARD define at
+	 * ~/include/linux/frame.h
+	 */
+	.macro	asm_stack_frame_non_standard	func
+	.pushsection ".discard.func_stack_frame_non_standard"
+	.quad	\func
+	.popsection
+	.endm

+#endif /* __ASSEMBLY__ */
 #else /* !CONFIG_STACK_VALIDATION */

+#ifndef __ASSEMBLY__
 #define STACK_FRAME_NON_STANDARD(func)
-
+#else
+	.macro	asm_stack_frame_non_standard	func
+	.endm
+#endif /* __ASSEMBLY__ */
 #endif /* CONFIG_STACK_VALIDATION */

 #endif /* _LINUX_FRAME_H */