Re: [PATCH v4 bpf-next 9/9] selftests/bpf: Test epilogue patching when the main prog has multiple BPF_EXIT

[Martin KaFai Lau <martin.lau@linux.dev>]

On 8/28/24 11:28 PM, Eduard Zingerman wrote:
> On Tue, 2024-08-27 at 17:58 -0700, Martin KaFai Lau wrote:
> 
> [...]
> 
>>> +SEC("struct_ops/test_epilogue_exit")
>>> +__naked int test_epilogue_exit(void)
>>> +{
>>> +	asm volatile (
>>> +	"r1 = *(u64 *)(r1 +0);"
>>> +	"r2 = *(u32 *)(r1 +0);"
>>> +	"if r2 == 0 goto +3;"
>>> +	"r0 = 0;"
>>> +	"*(u32 *)(r1 + 0) = 0;"
>>
>> llvm17 cannot take "*(u32 *)(r1 +0) = 0".
>>
>> Instead:
>>
>> r3 = 0;
>> *(u32 *)(r1 + 0) = r3;
>>
>> The above solved the llvm17 error:
>> https://github.com/kernel-patches/bpf/actions/runs/10586206183/job/29334690461
>>
>> However, there is still a zext with s390 that added extra insn and failed the
>> __xlated check. will try an adjustment in the tests to avoid the zext.
> 
> Another option would be to limit archs for the test, e.g. use
> __arch_x86_64 and __arch_arm64.

Ah. good to know.

I have used all 64bits ops to solve it. It passed the earlier bpf CI run:
https://github.com/kernel-patches/bpf/actions/runs/10590714532
I will respin with the 64bits ops solution.