Re: [PATCH bpf-next v9 3/4] bpf, arm64: Implement bpf_arch_text_poke() for arm64

[Jon Hunter]

On 18/07/2022 16:37, Xu Kuohai wrote:
> On 7/18/2022 9:52 PM, Jon Hunter wrote:
>
> [..]
> > This change appears to be causing the build to fail ...
> >
> > /tmp/cc52xO0c.s: Assembler messages:
> > /tmp/cc52xO0c.s:8: Error: operand 1 should be an integer register --
> > `mov lr,x9'
> > /tmp/cc52xO0c.s:7: Error: undefined symbol lr used as an immediate value
> > make[2]: *** [scripts/Makefile.build:250: arch/arm64/net/bpf_jit_comp.o]
> > Error 1
> > make[1]: *** [scripts/Makefile.build:525: arch/arm64/net] Error 2
> >
> > Let me know if you have any thoughts.
>
> Sorry for this failure, but I can't reproduce it.
>
> I guess maybe your assembler doesn't recognize "lr". Could you give a
> try to replace "lr" with "x30"?
>
>   #if IS_ENABLED(CONFIG_ARM64_BTI_KERNEL)
>   "      bti j\n" /* dummy_tramp is called via "br x10" */
>   #endif
> -"      mov x10, lr\n"
> -"      mov lr, x9\n"
> +"      mov x10, x30\n"
> +"      mov x30, x9\n"
>   "      ret x10\n"
>   "      .size dummy_tramp, .-dummy_tramp\n"
>   "      .popsection\n
>
> Thanks.


Sorry for delay, this did not seem to land in my inbox. Anyway, yes this 
fixes the build issue for me!

Thanks!
Jon

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