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From: Dapeng Mi <dapeng1.mi@linux.intel.com>
To: Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@redhat.com>,
	Arnaldo Carvalho de Melo <acme@kernel.org>,
	Namhyung Kim <namhyung@kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	Ian Rogers <irogers@google.com>,
	Adrian Hunter <adrian.hunter@intel.com>,
	Jiri Olsa <jolsa@kernel.org>,
	Alexander Shishkin <alexander.shishkin@linux.intel.com>,
	Andi Kleen <ak@linux.intel.com>,
	Eranian Stephane <eranian@google.com>
Cc: Mark Rutland <mark.rutland@arm.com>,
	broonie@kernel.org, Ravi Bangoria <ravi.bangoria@amd.com>,
	linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org,
	Zide Chen <zide.chen@intel.com>,
	Falcon Thomas <thomas.falcon@intel.com>,
	Dapeng Mi <dapeng1.mi@intel.com>,
	Xudong Hao <xudong.hao@intel.com>,
	Dapeng Mi <dapeng1.mi@linux.intel.com>,
	Kan Liang <kan.liang@linux.intel.com>
Subject: [Patch v10 16/23] perf/x86: Support OPMASK sampling using sample_simd_pred_reg_* fields
Date: Tue, 21 Jul 2026 14:24:59 +0800	[thread overview]
Message-ID: <20260721062506.3745816-17-dapeng1.mi@linux.intel.com> (raw)
In-Reply-To: <20260721062506.3745816-1-dapeng1.mi@linux.intel.com>

Support sampling of OPMASK registers via the sample_simd_pred_reg_*
fields.

Each OPMASK register consists of 1 u64 word. Current x86 hardware
supports 8 OPMASK registers. The perf_simd_reg_value() function is
responsible for outputting OPMASK value to userspace.

Additionally, sample_simd_pred_reg_qwords should be set to 1 to indicate
OPMASK sampling.

OPMASK sampling will be enabled in a subsequent patch that sets
PERF_PMU_CAP_SIMD_REGS.

Co-developed-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
---
 arch/x86/events/core.c                | 13 +++++++++++--
 arch/x86/events/perf_event.h          | 27 +++++++++++++++++++++++++++
 arch/x86/include/asm/perf_event.h     |  4 ++++
 arch/x86/include/uapi/asm/perf_regs.h |  5 +++++
 arch/x86/kernel/perf_regs.c           | 24 +++++++++++++++++++-----
 5 files changed, 66 insertions(+), 7 deletions(-)

diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c
index b0e3f1b9fa19..9bfb1810a9fe 100644
--- a/arch/x86/events/core.c
+++ b/arch/x86/events/core.c
@@ -642,10 +642,11 @@ static int pebs_simd_regs_validate(struct perf_event *event)
 	if (event_needs_xmm(event) &&
 	    x86_pmu.arch_pebs && !(caps & ARCH_PEBS_VECR_XMM))
 		return -EINVAL;
-	/* PEBS does not support YMM/ZMM registers sampling yet. */
+	/* PEBS does not support YMM/ZMM/OPMASK registers sampling yet. */
 	if (event_needs_ymm(event) ||
 	    event_needs_low16_zmm(event) ||
-	    event_needs_high16_zmm(event))
+	    event_needs_high16_zmm(event) ||
+	    event_needs_opmask(event))
 		return -EINVAL;
 
 	return 0;
@@ -670,6 +671,9 @@ static int event_simd_regs_validate(struct perf_event *event)
 	if (event_needs_high16_zmm(event) &&
 	    !(x86_pmu.ext_regs_mask & XFEATURE_MASK_Hi16_ZMM))
 		return -EINVAL;
+	if (event_needs_opmask(event) &&
+	    !(x86_pmu.ext_regs_mask & XFEATURE_MASK_OPMASK))
+		return -EINVAL;
 
 	return 0;
 }
@@ -1836,6 +1840,7 @@ void x86_pmu_clear_perf_regs(struct pt_regs *regs)
 	perf_regs->ymmh_regs = NULL;
 	perf_regs->zmmh_regs = NULL;
 	perf_regs->h16zmm_regs = NULL;
+	perf_regs->opmask_regs = NULL;
 }
 
 static void update_perf_regs(struct x86_perf_regs *perf_regs,
@@ -1857,6 +1862,8 @@ static void update_perf_regs(struct x86_perf_regs *perf_regs,
 		perf_regs->zmmh = get_xsave_addr(xsave, XFEATURE_ZMM_Hi256);
 	if (mask & XFEATURE_MASK_Hi16_ZMM)
 		perf_regs->h16zmm = get_xsave_addr(xsave, XFEATURE_Hi16_ZMM);
+	if (mask & XFEATURE_MASK_OPMASK)
+		perf_regs->opmask = get_xsave_addr(xsave, XFEATURE_OPMASK);
 }
 
 /*
@@ -2031,6 +2038,8 @@ static u64 get_simd_sample_mask(struct perf_event *event, u64 sample_type)
 		mask |= XFEATURE_MASK_ZMM_Hi256;
 	if (__event_needs_high16_zmm(event, sample_type))
 		mask |= XFEATURE_MASK_Hi16_ZMM;
+	if (__event_needs_opmask(event, sample_type))
+		mask |= XFEATURE_MASK_OPMASK;
 
 	return mask;
 }
diff --git a/arch/x86/events/perf_event.h b/arch/x86/events/perf_event.h
index f59551200f18..e6365438bb3d 100644
--- a/arch/x86/events/perf_event.h
+++ b/arch/x86/events/perf_event.h
@@ -263,6 +263,33 @@ static inline bool event_needs_high16_zmm(struct perf_event *event)
 			PERF_SAMPLE_REGS_INTR | PERF_SAMPLE_REGS_USER);
 }
 
+static inline bool __event_needs_opmask(struct perf_event *event,
+					u64 sample_type)
+{
+	if (!event->attr.sample_simd_regs_enabled)
+		return false;
+	if (event->attr.sample_simd_pred_reg_qwords != PERF_X86_OPMASK_QWORDS)
+		return false;
+
+	if ((sample_type & PERF_SAMPLE_REGS_USER) &&
+	    (event->attr.sample_type & PERF_SAMPLE_REGS_USER) &&
+	    (event->attr.sample_simd_pred_reg_user > 0))
+		return true;
+
+	if ((sample_type & PERF_SAMPLE_REGS_INTR) &&
+	    (event->attr.sample_type & PERF_SAMPLE_REGS_INTR) &&
+	    (event->attr.sample_simd_pred_reg_intr > 0))
+		return true;
+
+	return false;
+}
+
+static inline bool event_needs_opmask(struct perf_event *event)
+{
+	return __event_needs_opmask(event,
+			PERF_SAMPLE_REGS_INTR | PERF_SAMPLE_REGS_USER);
+}
+
 struct amd_nb {
 	int nb_id;  /* NorthBridge id */
 	int refcnt; /* reference count */
diff --git a/arch/x86/include/asm/perf_event.h b/arch/x86/include/asm/perf_event.h
index 75394c4e8bc3..49112e097e99 100644
--- a/arch/x86/include/asm/perf_event.h
+++ b/arch/x86/include/asm/perf_event.h
@@ -745,6 +745,10 @@ struct x86_perf_regs {
 		u64	*h16zmm_regs;
 		struct avx_512_hi16_state *h16zmm;
 	};
+	union {
+		u64	*opmask_regs;
+		struct avx_512_opmask_state *opmask;
+	};
 };
 
 extern unsigned long perf_arch_instruction_pointer(struct pt_regs *regs);
diff --git a/arch/x86/include/uapi/asm/perf_regs.h b/arch/x86/include/uapi/asm/perf_regs.h
index b88d0b6822fd..61aec60623f1 100644
--- a/arch/x86/include/uapi/asm/perf_regs.h
+++ b/arch/x86/include/uapi/asm/perf_regs.h
@@ -62,14 +62,19 @@ enum {
 	PERF_X86_SIMD_YMM_REGS      = 16,
 	PERF_X86_SIMD_ZMM_REGS      = 32,
 	PERF_X86_SIMD_VEC_REGS_MAX  = PERF_X86_SIMD_ZMM_REGS,
+
+	PERF_X86_SIMD_OPMASK_REGS   = 8,
+	PERF_X86_SIMD_PRED_REGS_MAX = PERF_X86_SIMD_OPMASK_REGS,
 };
 
+#define PERF_X86_SIMD_PRED_MASK	__GENMASK(PERF_X86_SIMD_PRED_REGS_MAX - 1, 0)
 #define PERF_X86_SIMD_VEC_MASK	__GENMASK_ULL(PERF_X86_SIMD_VEC_REGS_MAX - 1, 0)
 
 #define PERF_X86_H16ZMM_BASE		16
 
 enum {
 	/* 1 qword = 8 bytes */
+	PERF_X86_OPMASK_QWORDS   = 1,
 	PERF_X86_XMM_QWORDS      = 2,
 	PERF_X86_YMM_QWORDS      = 4,
 	PERF_X86_ZMM_QWORDS      = 8,
diff --git a/arch/x86/kernel/perf_regs.c b/arch/x86/kernel/perf_regs.c
index 93370d465786..87297da5e44b 100644
--- a/arch/x86/kernel/perf_regs.c
+++ b/arch/x86/kernel/perf_regs.c
@@ -89,8 +89,14 @@ u64 perf_simd_reg_value(struct pt_regs *regs, int idx,
 	if (!(perf_regs->abi & PERF_SAMPLE_REGS_ABI_SIMD))
 		return 0;
 
-	if (pred)
-		return 0;
+	if (pred) {
+		if (WARN_ON_ONCE(idx >= PERF_X86_SIMD_PRED_REGS_MAX ||
+				 qwords_idx >= PERF_X86_OPMASK_QWORDS))
+			return 0;
+		if (!perf_regs->opmask_regs)
+			return 0;
+		return perf_regs->opmask_regs[idx];
+	}
 
 	if (WARN_ON_ONCE(idx >= PERF_X86_SIMD_VEC_REGS_MAX ||
 			 qwords_idx >= PERF_X86_SIMD_QWORDS_MAX))
@@ -154,9 +160,17 @@ int perf_simd_reg_validate(u16 vec_qwords, u64 vec_mask,
 			return -EINVAL;
 	}
 
-	/* PRED registers are not supported yet. */
-	if (pred_qwords)
-		return -EINVAL;
+	if (pred_qwords) {
+		if (pred_qwords != PERF_X86_OPMASK_QWORDS)
+			return -EINVAL;
+		if (pred_mask & ~PERF_X86_SIMD_PRED_MASK)
+			return -EINVAL;
+		/* Only full-register sampling is allowed. */
+		mask = pred_mask;
+		if (pred_qwords == PERF_X86_OPMASK_QWORDS && mask &&
+		    !bitmap_full(&mask, PERF_X86_SIMD_OPMASK_REGS))
+			return -EINVAL;
+	}
 
 	size = sizeof(u64) * 4;
 	size += (hweight64(vec_mask) * vec_qwords +
-- 
2.34.1


  parent reply	other threads:[~2026-07-21  6:33 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-07-21  6:24 [Patch v10 00/23] Support SIMD/eGPRs/SSP registers sampling for perf Dapeng Mi
2026-07-21  6:24 ` [Patch v10 01/23] perf/x86: Move hybrid PMU initialization before x86_pmu_starting_cpu() Dapeng Mi
2026-07-21  6:24 ` [Patch v10 02/23] perf/x86/intel: Enable large PEBS sampling for XMMs Dapeng Mi
2026-07-21  6:24 ` [Patch v10 03/23] perf/x86/intel: Convert x86_perf_regs to per-cpu variables Dapeng Mi
2026-07-21  6:24 ` [Patch v10 04/23] perf: Eliminate duplicate arch-specific function definitions Dapeng Mi
2026-07-21  6:24 ` [Patch v10 05/23] perf/x86: Use x86_perf_regs in NMI handlers Dapeng Mi
2026-07-21  6:24 ` [Patch v10 06/23] x86/fpu/xstate: Add xsaves_nmi() helper Dapeng Mi
2026-07-21  6:24 ` [Patch v10 07/23] x86/fpu: Add update_fpu_state_and_flag() helper Dapeng Mi
2026-07-21  6:24 ` [Patch v10 08/23] perf: Move and enhance has_extended_regs() for arch-specific use Dapeng Mi
2026-07-21  6:24 ` [Patch v10 09/23] perf/x86/intel: Centralize PERF_PMU_CAP_EXTENDED_REGS updates Dapeng Mi
2026-07-21  6:24 ` [Patch v10 10/23] perf/x86: Enable XMM register sampling for non-PEBS events Dapeng Mi
2026-07-21  6:24 ` [Patch v10 11/23] perf/x86: Enable XMM register sampling for REGS_USER case Dapeng Mi
2026-07-21  6:24 ` [Patch v10 12/23] perf: Add sampling support for SIMD registers Dapeng Mi
2026-07-21  6:24 ` [Patch v10 13/23] perf/x86: Support XMM sampling using sample_simd_vec_reg_* fields Dapeng Mi
2026-07-21  6:24 ` [Patch v10 14/23] perf/x86: Support YMM " Dapeng Mi
2026-07-21  6:24 ` [Patch v10 15/23] perf/x86: Support ZMM " Dapeng Mi
2026-07-21  6:24 ` Dapeng Mi [this message]
2026-07-21  6:25 ` [Patch v10 17/23] perf: Enhance perf_reg_validate() with simd_enabled argument Dapeng Mi
2026-07-21  6:25 ` [Patch v10 18/23] perf/x86: Support eGPRs sampling using sample_regs_* fields Dapeng Mi
2026-07-21  6:25 ` [Patch v10 19/23] perf/x86: Support SSP " Dapeng Mi
2026-07-21  6:25 ` [Patch v10 20/23] perf/x86/intel: Support arch-PEBS based SIMD/eGPRs sampling Dapeng Mi
2026-07-21  6:25 ` [Patch v10 21/23] perf/x86/intel: Advertise PERF_PMU_CAP_SIMD_REGS capability Dapeng Mi
2026-07-21  6:25 ` [Patch v10 22/23] perf/x86: Activate back-to-back NMI detection for arch-PEBS induced NMIs Dapeng Mi
2026-07-21  6:25 ` [Patch v10 23/23] perf/x86/intel: Add sanity check for PEBS record/fragment size Dapeng Mi
2026-07-21 17:42 ` [Patch v10 00/23] Support SIMD/eGPRs/SSP registers sampling for perf Ian Rogers
2026-07-22  0:17   ` Mi, Dapeng

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