[PATCH Resend] ARM64:ftrace: fix ftrace_modify_graph_caller for branch replace
AKASHI Takahiro
takahiro.akashi at linaro.org
Mon Feb 16 16:12:19 PST 2015
On 02/13/2015 01:06 PM, Pratyush Anand wrote:
> ftrace_enable_ftrace_graph_caller and ftrace_disable_ftrace_graph_caller
> should replace B(jmp) instruction and not BL(call) instruction.
Thanks. I originally intended to use "b".
("bl" may also work anyway 'cause link register will be saved/restored
around ftrace_caller().)
-Takahiro AKASHI
> commit 9f1ae7596aad("arm64: Correct ftrace calls to
> aarch64_insn_gen_branch_imm()") did a typo and used
> AARCH64_INSN_BRANCH_LINK instead of AARCH64_INSN_BRANCH_NOLINK.
>
> Signed-off-by: Pratyush Anand <panand at redhat.com>
> ---
> arch/arm64/kernel/ftrace.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/arm64/kernel/ftrace.c b/arch/arm64/kernel/ftrace.c
> index cf8556ae09d0..c851be795080 100644
> --- a/arch/arm64/kernel/ftrace.c
> +++ b/arch/arm64/kernel/ftrace.c
> @@ -156,7 +156,7 @@ static int ftrace_modify_graph_caller(bool enable)
>
> branch = aarch64_insn_gen_branch_imm(pc,
> (unsigned long)ftrace_graph_caller,
> - AARCH64_INSN_BRANCH_LINK);
> + AARCH64_INSN_BRANCH_NOLINK);
> nop = aarch64_insn_gen_nop();
>
> if (enable)
>
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