Re: [tip: core/kprobes] arm/ftrace: Use __patch_text()

Dmitry Osipenko
2020-02-07T16:47:46Z

07.02.2020 14:27, Peter Zijlstra пишет:
>> NVIDIA Tegra20/30 are not booting with CONFIG_FTRACE=y, but even with
>> CONFIG_FTRACE=n things are not working well.
>
> Ooh, I think I see. Can you try this:
>
> diff --git a/arch/arm/kernel/ftrace.c b/arch/arm/kernel/ftrace.c
> index 2a5ff69c28e6..10499d44964a 100644
> --- a/arch/arm/kernel/ftrace.c
> +++ b/arch/arm/kernel/ftrace.c
> @@ -78,13 +78,10 @@ static int ftrace_modify_code(unsigned long pc, unsigned long old,
> {
> unsigned long replaced;
>
> - if (IS_ENABLED(CONFIG_THUMB2_KERNEL)) {
> + if (IS_ENABLED(CONFIG_THUMB2_KERNEL))
> old = __opcode_to_mem_thumb32(old);
> - new = __opcode_to_mem_thumb32(new);
> - } else {
> + else
> old = __opcode_to_mem_arm(old);
> - new = __opcode_to_mem_arm(new);
> - }
>
> if (validate) {
> if (probe_kernel_read(&replaced, (void *)pc, MCOUNT_INSN_SIZE))
>

Hello Peter,

It fixes the problem, at least kernel is booting fine now and I can't
notice any problems. Thank you very much! :)

Tested-by: Dmitry Osipenko <digetx@gmail.com>