On Wed, Oct 16, 2024 at 09:59:00AM +0900, Masami Hiramatsu (Google) wrote:
> From: Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx>
>
> Add ftrace_partial_regs() which converts the ftrace_regs to pt_regs.
> This is for the eBPF which needs this to keep the same pt_regs interface
> to access registers.
> Thus when replacing the pt_regs with ftrace_regs in fprobes (which is
> used by kprobe_multi eBPF event), this will be used.
>
> If the architecture defines its own ftrace_regs, this copies partial
> registers to pt_regs and returns it. If not, ftrace_regs is the same as
> pt_regs and ftrace_partial_regs() will return ftrace_regs::regs.
>
> Signed-off-by: Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx>
> Acked-by: Florent Revest <revest@xxxxxxxxxxxx>
> Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
> Cc: Mark Rutland <mark.rutland@xxxxxxx>
> Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
> Cc: Will Deacon <will@xxxxxxxxxx>
> Cc: Paul Walmsley <paul.walmsley@xxxxxxxxxx>
> Cc: Palmer Dabbelt <palmer@xxxxxxxxxxx>
> Cc: Albert Ou <aou@xxxxxxxxxxxxxxxxx>
>
> ---
> Changes in v14:
> - Add riscv change.
> Changes in v8:
> - Add the reason why this required in changelog.
> Changes from previous series: NOTHING, just forward ported.
> ---
> arch/arm64/include/asm/ftrace.h | 11 +++++++++++
> arch/riscv/include/asm/ftrace.h | 14 ++++++++++++++
> include/linux/ftrace.h | 17 +++++++++++++++++
> 3 files changed, 42 insertions(+)
>
> diff --git a/arch/arm64/include/asm/ftrace.h b/arch/arm64/include/asm/ftrace.h
> index b5fa57b61378..d344c69eb01e 100644
> --- a/arch/arm64/include/asm/ftrace.h
> +++ b/arch/arm64/include/asm/ftrace.h
> @@ -135,6 +135,17 @@ ftrace_regs_get_frame_pointer(const struct ftrace_regs *fregs)
> return arch_ftrace_regs(fregs)->fp;
> }
>
> +static __always_inline struct pt_regs *
> +ftrace_partial_regs(const struct ftrace_regs *fregs, struct pt_regs *regs)
> +{
> + memcpy(regs->regs, arch_ftrace_regs(fregs)->regs, sizeof(u64) * 9);
Since ftrace_regs::regs is an 'unsigned long regs[9]' can we just use
sizeof() on that instead of hard-coding the length of the array here?
Will
