linux-kernel - [PATCH 6/7] perf/x86: Replace magic numbers with macros for attr

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Message-Id: <20251120053431.491677-7-dapeng1.mi@linux.intel.com>
Date: Thu, 20 Nov 2025 13:34:30 +0800
From: Dapeng Mi <dapeng1.mi@...ux.intel.com>
To: Peter Zijlstra <peterz@...radead.org>,
	Ingo Molnar <mingo@...hat.com>,
	Arnaldo Carvalho de Melo <acme@...nel.org>,
	Namhyung Kim <namhyung@...nel.org>,
	Ian Rogers <irogers@...gle.com>,
	Adrian Hunter <adrian.hunter@...el.com>,
	Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
	Andi Kleen <ak@...ux.intel.com>,
	Eranian Stephane <eranian@...gle.com>
Cc: linux-kernel@...r.kernel.org,
	linux-perf-users@...r.kernel.org,
	Dapeng Mi <dapeng1.mi@...el.com>,
	Zide Chen <zide.chen@...el.com>,
	Falcon Thomas <thomas.falcon@...el.com>,
	Xudong Hao <xudong.hao@...el.com>,
	Dapeng Mi <dapeng1.mi@...ux.intel.com>
Subject: [PATCH 6/7] perf/x86: Replace magic numbers with macros for attr_rdpmc

Use macros to replace these attr_rdpmc magic numbers, so users are easy
to know their meaning.

Signed-off-by: Dapeng Mi <dapeng1.mi@...ux.intel.com>
---
 arch/x86/events/core.c       | 7 ++++---
 arch/x86/events/intel/p6.c   | 2 +-
 arch/x86/events/perf_event.h | 7 +++++++
 3 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c
index 5d0d5e466c62..3d9cc1d7fcfa 100644
--- a/arch/x86/events/core.c
+++ b/arch/x86/events/core.c
@@ -2129,7 +2129,8 @@ static int __init init_hw_perf_events(void)
 
 	pr_cont("%s PMU driver.\n", x86_pmu.name);
 
-	x86_pmu.attr_rdpmc = 1; /* enable userspace RDPMC usage by default */
+	/* enable userspace RDPMC usage by default */
+	x86_pmu.attr_rdpmc = X86_USER_RDPMC_CONDITIONAL_ENABLE;
 
 	for (quirk = x86_pmu.quirks; quirk; quirk = quirk->next)
 		quirk->func();
@@ -2609,12 +2610,12 @@ static ssize_t set_attr_rdpmc(struct device *cdev,
 		 */
 		if (val == 0)
 			static_branch_inc(&rdpmc_never_available_key);
-		else if (x86_pmu.attr_rdpmc == 0)
+		else if (x86_pmu.attr_rdpmc == X86_USER_RDPMC_NEVER_ENABLE)
 			static_branch_dec(&rdpmc_never_available_key);
 
 		if (val == 2)
 			static_branch_inc(&rdpmc_always_available_key);
-		else if (x86_pmu.attr_rdpmc == 2)
+		else if (x86_pmu.attr_rdpmc == X86_USER_RDPMC_ALWAYS_ENABLE)
 			static_branch_dec(&rdpmc_always_available_key);
 
 		on_each_cpu(cr4_update_pce, NULL, 1);
diff --git a/arch/x86/events/intel/p6.c b/arch/x86/events/intel/p6.c
index 6e41de355bd8..fb991e0ac614 100644
--- a/arch/x86/events/intel/p6.c
+++ b/arch/x86/events/intel/p6.c
@@ -243,7 +243,7 @@ static __init void p6_pmu_rdpmc_quirk(void)
 		 */
 		pr_warn("Userspace RDPMC support disabled due to a CPU erratum\n");
 		x86_pmu.attr_rdpmc_broken = 1;
-		x86_pmu.attr_rdpmc = 0;
+		x86_pmu.attr_rdpmc = X86_USER_RDPMC_NEVER_ENABLE;
 	}
 }
 
diff --git a/arch/x86/events/perf_event.h b/arch/x86/events/perf_event.h
index f7caabc5d487..24a81d2916e9 100644
--- a/arch/x86/events/perf_event.h
+++ b/arch/x86/events/perf_event.h
@@ -187,6 +187,13 @@ struct amd_nb {
 	 (1ULL << PERF_REG_X86_R14)   | \
 	 (1ULL << PERF_REG_X86_R15))
 
+/* user space rdpmc control values */
+enum {
+	X86_USER_RDPMC_NEVER_ENABLE		= 0,
+	X86_USER_RDPMC_CONDITIONAL_ENABLE	= 1,
+	X86_USER_RDPMC_ALWAYS_ENABLE		= 2,
+};
+
 /*
  * Per register state.
  */
-- 
2.34.1