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

[Guenter Roeck]

On 3/14/24 00:57, Geert Uytterhoeven wrote:
> Hi Günter,
> 
> On Tue, Mar 12, 2024 at 6:06 PM Guenter Roeck <linux at 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 at 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\", at progbits,1\n"    \
>>                  "1:     .asciz  \""__FILE__"\"\n"               \
>>                  ".previous\n"                                   \
>> -               ".section __bug_table,\"awM\", at progbits,%2\n"   \
>> +               ".section __bug_table,\"awM\", at 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