[PATCH 2/2] powerpc/fprobe: fix updated fprobe for function-graph tracer

[Masami Hiramatsu (Google)]

On Wed, 28 May 2025 19:18:20 +0530
Aditya Bodkhe <adityab1 at linux.ibm.com> wrote:

> From: Hari Bathini <hbathini at linux.ibm.com>
> 
> Since commit 4346ba160409 ("fprobe: Rewrite fprobe on function-graph
> tracer"), FPROBE depends on HAVE_FUNCTION_GRAPH_FREGS. With previous
> patch adding HAVE_FUNCTION_GRAPH_FREGS for powerpc, FPROBE can be
> enabled on powerpc. But with the commit b5fa903b7f7c ("fprobe: Add
> fprobe_header encoding feature"), asm/fprobe.h header is needed to
> define arch dependent encode/decode macros. The fprobe header MSB
> pattern on powerpc is not 0xf. So, define FPROBE_HEADER_MSB_PATTERN
> expected on powerpc.
> 
> Also, commit 762abbc0d09f ("fprobe: Use ftrace_regs in fprobe exit
> handler") introduced HAVE_FTRACE_REGS_HAVING_PT_REGS for archs that
> have pt_regs in ftrace_regs. Advertise that on powerpc to reuse
> common definitions like ftrace_partial_regs().
> 
> Signed-off-by: Hari Bathini <hbathini at linux.ibm.com>
> Signed-off-by: Aditya Bodkhe <aditya.b1 at linux.ibm.com>

This patch in this series looks good to me.

Acked-by: Masami Hiramatsu (Google) <mhiramat at kernel.org>

I think this series go through powerpc tree. But you have
some comments on 1/2, so please solve it at first.

Thank you,

> ---
>  arch/powerpc/Kconfig              |  1 +
>  arch/powerpc/include/asm/fprobe.h | 12 ++++++++++++
>  2 files changed, 13 insertions(+)
>  create mode 100644 arch/powerpc/include/asm/fprobe.h
> 
> diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
> index 9163521bc4b9..2203e4fb64c1 100644
> --- a/arch/powerpc/Kconfig
> +++ b/arch/powerpc/Kconfig
> @@ -246,6 +246,7 @@ config PPC
>  	select HAVE_EFFICIENT_UNALIGNED_ACCESS
>  	select HAVE_GUP_FAST
>  	select HAVE_FTRACE_GRAPH_FUNC
> +	select HAVE_FTRACE_REGS_HAVING_PT_REGS
>  	select HAVE_FTRACE_MCOUNT_RECORD
>  	select HAVE_FUNCTION_ARG_ACCESS_API
>  	select HAVE_FUNCTION_DESCRIPTORS	if PPC64_ELF_ABI_V1
> diff --git a/arch/powerpc/include/asm/fprobe.h b/arch/powerpc/include/asm/fprobe.h
> new file mode 100644
> index 000000000000..d64bc28fb3d3
> --- /dev/null
> +++ b/arch/powerpc/include/asm/fprobe.h
> @@ -0,0 +1,12 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +#ifndef _ASM_PPC_FPROBE_H
> +#define _ASM_PPC_FPROBE_H
> +
> +#include <asm-generic/fprobe.h>
> +
> +#ifdef CONFIG_64BIT
> +#undef FPROBE_HEADER_MSB_PATTERN
> +#define FPROBE_HEADER_MSB_PATTERN	(PAGE_OFFSET & ~FPROBE_HEADER_MSB_MASK)
> +#endif
> +
> +#endif /* _ASM_PPC_FPROBE_H */
> -- 
> 2.43.5
> 


-- 
Masami Hiramatsu (Google) <mhiramat at kernel.org>