linux-kernel - [PATCH v2] riscv: perf: Drop defining `perf_instruction_pointer()` and `perf_misc

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Message-ID: <20241116160506.5324-1-prabhakar.mahadev-lad.rj@bp.renesas.com>
Date: Sat, 16 Nov 2024 16:05:06 +0000
From: Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>
To: Peter Zijlstra <peterz@...radead.org>,
	Ingo Molnar <mingo@...hat.com>,
	Arnaldo Carvalho de Melo <acme@...nel.org>,
	Namhyung Kim <namhyung@...nel.org>,
	Mark Rutland <mark.rutland@....com>,
	Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
	Jiri Olsa <jolsa@...nel.org>,
	Ian Rogers <irogers@...gle.com>,
	Adrian Hunter <adrian.hunter@...el.com>,
	"Liang, Kan" <kan.liang@...ux.intel.com>,
	Paul Walmsley <paul.walmsley@...ive.com>,
	Palmer Dabbelt <palmer@...belt.com>,
	Albert Ou <aou@...s.berkeley.edu>,
	Colton Lewis <coltonlewis@...gle.com>,
	Oliver Upton <oliver.upton@...ux.dev>,
	Geert Uytterhoeven <geert+renesas@...der.be>,
	linux-perf-users@...r.kernel.org
Cc: 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>,
	Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>,
	Chris Paterson <Chris.Paterson2@...esas.com>,
	Andrew Jones <ajones@...tanamicro.com>
Subject: [PATCH v2] riscv: perf: Drop defining `perf_instruction_pointer()` and `perf_misc_flags()`

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 change also fixes the following build issue on RISC-V:

    ./include/linux/perf_event.h:1679:84: error: macro "perf_misc_flags" passed 2 arguments, but takes just 1
    ./include/linux/perf_event.h:1679:22: error: 'perf_misc_flags' redeclared as different kind of symbol
    ./include/linux/perf_event.h:1680:22: error: conflicting types for 'perf_instruction_pointer'; have 'long unsigned int(struct perf_event *, struct pt_regs *)'

The above errors arise from conflicts between the core definitions in
`linux/perf_event.h` and the RISC-V-specific definitions in
`arch/riscv/include/asm/perf_event.h`. Removing the RISC-V-specific
definitions resolves these issues and aligns the architecture with the
updated perf core.

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>
Reviewed-by: Andrew Jones <ajones@...tanamicro.com>
---
v1->v2
- Update commit message to say it fixes build issue
- Included RB tag from Andrew
---
 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