Re: [RFC PATCH 2/2] objtool/LoongArch: Fix unreachable instruction warnings about head.S

[Tiezhu Yang <yangtiezhu@loongson.cn>]

On 2025/8/26 下午4:20, Peter Zijlstra wrote:
> On Tue, Aug 26, 2025 at 02:46:31PM +0800, Tiezhu Yang wrote:
>> When compiling with LLVM and CONFIG_LTO_CLANG is set, there exist the
>> following objtool warnings after silencing all of the other warnings:

...

>> Just give a proper unwind hint to silence the above warnings. By the way,
>> the previous instructions of kernel_entry+0xf4 and smpboot_entry+0x68 are
>> the 'bl' instructions, the call destination symbols are start_kernel() and
>> start_secondary() which are noreturn functions, then the 'bl' instructions
>> are marked as dead end in annotate_call_site(), so actually ASM_BUG() can
>> be removed due to unnecessary, otherwise there are following warnings:

...

>> Link: https://lore.kernel.org/lkml/20250814083651.GR4067720@noisy.programming.kicks-ass.net/
>> Suggested-by: Peter Zijlstra <peterz@infradead.org>
>> Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
>> ---
>>   arch/loongarch/kernel/head.S | 8 ++++----
>>   1 file changed, 4 insertions(+), 4 deletions(-)
> 
> At this point you should also be able to remove that Makefile thing,
> right?

Yes, you are right, will do it in the next version if this patch
makes sense.

Thanks,
Tiezhu