diff mbox series

[11/14] s390: Add support for suppressing warning backtraces

Message ID 20240312170309.2546362-12-linux@roeck-us.net (mailing list archive)
State New, archived
Headers show
Series Add support for suppressing warning backtraces | expand

Commit Message

Guenter Roeck March 12, 2024, 5:03 p.m. UTC
Add name of functions triggering warning backtraces to the __bug_table
object section to enable support for suppressing WARNING backtraces.

To limit image size impact, the pointer to the function name is only added
to the __bug_table section if both CONFIG_KUNIT and CONFIG_DEBUG_BUGVERBOSE
are enabled. Otherwise, the __func__ assembly parameter is replaced with a
(dummy) NULL parameter to avoid an image size increase due to unused
__func__ entries (this is necessary because __func__ is not a define but a
virtual variable).

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
---
 arch/s390/include/asm/bug.h | 19 +++++++++++++++----
 1 file changed, 15 insertions(+), 4 deletions(-)

Comments

Geert Uytterhoeven March 14, 2024, 7:57 a.m. UTC | #1
Hi Günter,

On Tue, Mar 12, 2024 at 6:06 PM Guenter Roeck <linux@roeck-us.net> wrote:
> Add name of functions triggering warning backtraces to the __bug_table
> object section to enable support for suppressing WARNING backtraces.
>
> To limit image size impact, the pointer to the function name is only added
> to the __bug_table section if both CONFIG_KUNIT and CONFIG_DEBUG_BUGVERBOSE
> are enabled. Otherwise, the __func__ assembly parameter is replaced with a
> (dummy) NULL parameter to avoid an image size increase due to unused
> __func__ entries (this is necessary because __func__ is not a define but a
> virtual variable).
>
> Signed-off-by: Guenter Roeck <linux@roeck-us.net>

Thanks for your patch!

> --- a/arch/s390/include/asm/bug.h
> +++ b/arch/s390/include/asm/bug.h
> @@ -8,19 +8,30 @@
>
>  #ifdef CONFIG_DEBUG_BUGVERBOSE
>
> +#if IS_ENABLED(CONFIG_KUNIT)
> +# define HAVE_BUG_FUNCTION
> +# define __BUG_FUNC_PTR        "       .long   %0-.\n"
> +# define __BUG_FUNC    __func__
> +#else
> +# define __BUG_FUNC_PTR
> +# define __BUG_FUNC    NULL
> +#endif /* IS_ENABLED(CONFIG_KUNIT) */
> +
>  #define __EMIT_BUG(x) do {                                     \
>         asm_inline volatile(                                    \
>                 "0:     mc      0,0\n"                          \
>                 ".section .rodata.str,\"aMS\",@progbits,1\n"    \
>                 "1:     .asciz  \""__FILE__"\"\n"               \
>                 ".previous\n"                                   \
> -               ".section __bug_table,\"awM\",@progbits,%2\n"   \
> +               ".section __bug_table,\"awM\",@progbits,%3\n"   \

This change conflicts with commit 3938490e78f443fb ("s390/bug:
remove entry size from __bug_table section") in linus/master.
I guess it should just be dropped?

>                 "2:     .long   0b-.\n"                         \
>                 "       .long   1b-.\n"                         \
> -               "       .short  %0,%1\n"                        \
> -               "       .org    2b+%2\n"                        \
> +               __BUG_FUNC_PTR                                  \
> +               "       .short  %1,%2\n"                        \
> +               "       .org    2b+%3\n"                        \
>                 ".previous\n"                                   \
> -               : : "i" (__LINE__),                             \
> +               : : "i" (__BUG_FUNC),                           \
> +                   "i" (__LINE__),                             \
>                     "i" (x),                                    \
>                     "i" (sizeof(struct bug_entry)));            \
>  } while (0)

Gr{oetje,eeting}s,

                        Geert
Guenter Roeck March 14, 2024, 1:54 p.m. UTC | #2
On 3/14/24 00:57, Geert Uytterhoeven wrote:
> Hi Günter,
> 
> On Tue, Mar 12, 2024 at 6:06 PM Guenter Roeck <linux@roeck-us.net> wrote:
>> Add name of functions triggering warning backtraces to the __bug_table
>> object section to enable support for suppressing WARNING backtraces.
>>
>> To limit image size impact, the pointer to the function name is only added
>> to the __bug_table section if both CONFIG_KUNIT and CONFIG_DEBUG_BUGVERBOSE
>> are enabled. Otherwise, the __func__ assembly parameter is replaced with a
>> (dummy) NULL parameter to avoid an image size increase due to unused
>> __func__ entries (this is necessary because __func__ is not a define but a
>> virtual variable).
>>
>> Signed-off-by: Guenter Roeck <linux@roeck-us.net>
> 
> Thanks for your patch!
> 
>> --- a/arch/s390/include/asm/bug.h
>> +++ b/arch/s390/include/asm/bug.h
>> @@ -8,19 +8,30 @@
>>
>>   #ifdef CONFIG_DEBUG_BUGVERBOSE
>>
>> +#if IS_ENABLED(CONFIG_KUNIT)
>> +# define HAVE_BUG_FUNCTION
>> +# define __BUG_FUNC_PTR        "       .long   %0-.\n"
>> +# define __BUG_FUNC    __func__
>> +#else
>> +# define __BUG_FUNC_PTR
>> +# define __BUG_FUNC    NULL
>> +#endif /* IS_ENABLED(CONFIG_KUNIT) */
>> +
>>   #define __EMIT_BUG(x) do {                                     \
>>          asm_inline volatile(                                    \
>>                  "0:     mc      0,0\n"                          \
>>                  ".section .rodata.str,\"aMS\",@progbits,1\n"    \
>>                  "1:     .asciz  \""__FILE__"\"\n"               \
>>                  ".previous\n"                                   \
>> -               ".section __bug_table,\"awM\",@progbits,%2\n"   \
>> +               ".section __bug_table,\"awM\",@progbits,%3\n"   \
> 
> This change conflicts with commit 3938490e78f443fb ("s390/bug:
> remove entry size from __bug_table section") in linus/master.
> I guess it should just be dropped?
> 

Yes, I know. I'll send v2 rebased to v6.9-rc1 once it is available and,
yes, the change will be gone after that.

Thanks,
Guenter
diff mbox series

Patch

diff --git a/arch/s390/include/asm/bug.h b/arch/s390/include/asm/bug.h
index aebe1e22c7be..01e2aa4069d7 100644
--- a/arch/s390/include/asm/bug.h
+++ b/arch/s390/include/asm/bug.h
@@ -8,19 +8,30 @@ 
 
 #ifdef CONFIG_DEBUG_BUGVERBOSE
 
+#if IS_ENABLED(CONFIG_KUNIT)
+# define HAVE_BUG_FUNCTION
+# define __BUG_FUNC_PTR	"	.long	%0-.\n"
+# define __BUG_FUNC	__func__
+#else
+# define __BUG_FUNC_PTR
+# define __BUG_FUNC	NULL
+#endif /* IS_ENABLED(CONFIG_KUNIT) */
+
 #define __EMIT_BUG(x) do {					\
 	asm_inline volatile(					\
 		"0:	mc	0,0\n"				\
 		".section .rodata.str,\"aMS\",@progbits,1\n"	\
 		"1:	.asciz	\""__FILE__"\"\n"		\
 		".previous\n"					\
-		".section __bug_table,\"awM\",@progbits,%2\n"	\
+		".section __bug_table,\"awM\",@progbits,%3\n"	\
 		"2:	.long	0b-.\n"				\
 		"	.long	1b-.\n"				\
-		"	.short	%0,%1\n"			\
-		"	.org	2b+%2\n"			\
+		__BUG_FUNC_PTR					\
+		"	.short	%1,%2\n"			\
+		"	.org	2b+%3\n"			\
 		".previous\n"					\
-		: : "i" (__LINE__),				\
+		: : "i" (__BUG_FUNC),				\
+		    "i" (__LINE__),				\
 		    "i" (x),					\
 		    "i" (sizeof(struct bug_entry)));		\
 } while (0)