Re: [PATCH v17 07/16] tracing: Add ftrace_fill_perf_regs() for perf event
From: Will Deacon
Date: Mon Oct 21 2024 - 13:01:43 EST
On Wed, Oct 16, 2024 at 09:59:12AM +0900, Masami Hiramatsu (Google) wrote:
> From: Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx>
>
> Add ftrace_fill_perf_regs() which should be compatible with the
> perf_fetch_caller_regs(). In other words, the pt_regs returned from the
> ftrace_fill_perf_regs() must satisfy 'user_mode(regs) == false' and can be
> used for stack tracing.
>
> Signed-off-by: Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx>
> Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
> Cc: Mark Rutland <mark.rutland@xxxxxxx>
> Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
> Cc: Will Deacon <will@xxxxxxxxxx>
> Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
> Cc: Nicholas Piggin <npiggin@xxxxxxxxx>
> Cc: Christophe Leroy <christophe.leroy@xxxxxxxxxx>
> Cc: Naveen N Rao <naveen@xxxxxxxxxx>
> Cc: Madhavan Srinivasan <maddy@xxxxxxxxxxxxx>
> Cc: Heiko Carstens <hca@xxxxxxxxxxxxx>
> Cc: Vasily Gorbik <gor@xxxxxxxxxxxxx>
> Cc: Alexander Gordeev <agordeev@xxxxxxxxxxxxx>
> Cc: Christian Borntraeger <borntraeger@xxxxxxxxxxxxx>
> Cc: Sven Schnelle <svens@xxxxxxxxxxxxx>
> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> Cc: Ingo Molnar <mingo@xxxxxxxxxx>
> Cc: Borislav Petkov <bp@xxxxxxxxx>
> Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
> Cc: x86@xxxxxxxxxx
> Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
>
> ---
> Changes in v16:
> - Fix s390 to clear psw.mask according to Heiko's suggestion.
> ---
> arch/arm64/include/asm/ftrace.h | 7 +++++++
> arch/powerpc/include/asm/ftrace.h | 7 +++++++
> arch/s390/include/asm/ftrace.h | 6 ++++++
> arch/x86/include/asm/ftrace.h | 7 +++++++
> include/linux/ftrace.h | 31 +++++++++++++++++++++++++++++++
> 5 files changed, 58 insertions(+)
>
> diff --git a/arch/arm64/include/asm/ftrace.h b/arch/arm64/include/asm/ftrace.h
> index d344c69eb01e..6493a575664f 100644
> --- a/arch/arm64/include/asm/ftrace.h
> +++ b/arch/arm64/include/asm/ftrace.h
> @@ -146,6 +146,13 @@ ftrace_partial_regs(const struct ftrace_regs *fregs, struct pt_regs *regs)
> return regs;
> }
>
> +#define arch_ftrace_fill_perf_regs(fregs, _regs) do { \
> + (_regs)->pc = arch_ftrace_regs(fregs)->pc; \
> + (_regs)->regs[29] = arch_ftrace_regs(fregs)->fp; \
> + (_regs)->sp = arch_ftrace_regs(fregs)->sp; \
> + (_regs)->pstate = PSR_MODE_EL1h; \
> + } while (0)
arm64 bit looks correct to me:
Acked-by: Will Deacon <will@xxxxxxxxxx>
Will