linux-kernel - Re: [PATCH] riscv: perf: Drop defining `perf_instruction_pointer()` and `perf_misc

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Message-ID: <20241115-829a0b75f783dad6dac037a5@orel>
Date: Fri, 15 Nov 2024 13:11:18 +0100
From: Andrew Jones <ajones@...tanamicro.com>
To: Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>
Cc: Peter Zijlstra <peterz@...radead.org>, Ingo Molnar <mingo@...hat.com>, 
	Arnaldo Carvalho de Melo <acme@...nel.org>, Mark Rutland <mark.rutland@....com>, 
	Alexander Shishkin <alexander.shishkin@...ux.intel.com>, Jiri Olsa <jolsa@...nel.org>, Namhyung Kim <namhyung@...nel.org>, 
	Ian Rogers <irogers@...gle.com>, Adrian Hunter <adrian.hunter@...el.com>, 
	Paul Walmsley <paul.walmsley@...ive.com>, Palmer Dabbelt <palmer@...belt.com>, 
	Albert Ou <aou@...s.berkeley.edu>, Kan Liang <kan.liang@...ux.intel.com>, 
	Colton Lewis <coltonlewis@...gle.com>, Oliver Upton <oliver.upton@...ux.dev>, 
	Geert Uytterhoeven <geert+renesas@...der.be>, linux-perf-users@...r.kernel.org, linux-kernel@...r.kernel.org, 
	linux-riscv@...ts.infradead.org, linux-renesas-soc@...r.kernel.org, 
	Prabhakar <prabhakar.csengg@...il.com>, Biju Das <biju.das.jz@...renesas.com>, 
	Fabrizio Castro <fabrizio.castro.jz@...esas.com>, Chris Paterson <Chris.Paterson2@...esas.com>
Subject: Re: [PATCH] riscv: perf: Drop defining `perf_instruction_pointer()`
 and `perf_misc_flags()`

On Fri, Nov 15, 2024 at 11:13:45AM +0000, Prabhakar wrote:
> From: Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>
> 
> With commit 2c47e7a74f44 ("perf/core: Correct perf sampling with guest
> VMs"), the perf core now handles the functionality previously requiring
> arch-specific definitions of `perf_instruction_pointer()` and
> `perf_misc_flags()`. As these definitions are no longer necessary for
> RISC-V, this patch removes their implementation and declarations.
> 
> This cleanup aligns the RISC-V architecture with the updated perf core
> mechanism, reducing code redundancy and improving maintainability.
> 
> Fixes: 2c47e7a74f44 ("perf/core: Correct perf sampling with guest VMs")
> Reported-by: Chris Paterson <Chris.Paterson2@...esas.com>
> Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>
> ---
>  arch/riscv/include/asm/perf_event.h |  3 ---
>  arch/riscv/kernel/perf_callchain.c  | 28 ----------------------------
>  2 files changed, 31 deletions(-)
> 
> diff --git a/arch/riscv/include/asm/perf_event.h b/arch/riscv/include/asm/perf_event.h
> index 38926b4a902d..bcc928fd3785 100644
> --- a/arch/riscv/include/asm/perf_event.h
> +++ b/arch/riscv/include/asm/perf_event.h
> @@ -10,9 +10,6 @@
>  
>  #ifdef CONFIG_PERF_EVENTS
>  #include <linux/perf_event.h>
> -extern unsigned long perf_instruction_pointer(struct pt_regs *regs);
> -extern unsigned long perf_misc_flags(struct pt_regs *regs);
> -#define perf_misc_flags(regs) perf_misc_flags(regs)
>  #define perf_arch_bpf_user_pt_regs(regs) (struct user_regs_struct *)regs
>  
>  #define perf_arch_fetch_caller_regs(regs, __ip) { \
> diff --git a/arch/riscv/kernel/perf_callchain.c b/arch/riscv/kernel/perf_callchain.c
> index c2c81a80f816..b465bc9eb870 100644
> --- a/arch/riscv/kernel/perf_callchain.c
> +++ b/arch/riscv/kernel/perf_callchain.c
> @@ -46,31 +46,3 @@ void perf_callchain_kernel(struct perf_callchain_entry_ctx *entry,
>  
>  	walk_stackframe(NULL, regs, fill_callchain, entry);
>  }
> -
> -unsigned long perf_instruction_pointer(struct pt_regs *regs)
> -{
> -	if (perf_guest_state())
> -		return perf_guest_get_ip();
> -
> -	return instruction_pointer(regs);
> -}
> -
> -unsigned long perf_misc_flags(struct pt_regs *regs)
> -{
> -	unsigned int guest_state = perf_guest_state();
> -	unsigned long misc = 0;
> -
> -	if (guest_state) {
> -		if (guest_state & PERF_GUEST_USER)
> -			misc |= PERF_RECORD_MISC_GUEST_USER;
> -		else
> -			misc |= PERF_RECORD_MISC_GUEST_KERNEL;
> -	} else {
> -		if (user_mode(regs))
> -			misc |= PERF_RECORD_MISC_USER;
> -		else
> -			misc |= PERF_RECORD_MISC_KERNEL;
> -	}
> -
> -	return misc;
> -}
> -- 
> 2.25.1
>

Reviewed-by: Andrew Jones <ajones@...tanamicro.com>