[Patch v9 16/24] perf/x86: Support ZMM sampling using sample_simd_vec_reg_* fields

[Dapeng Mi <dapeng1.mi@linux.intel.com>]

Support sampling of ZMM registers via the sample_simd_vec_reg_* fields.

Each ZMM register consists of 8 u64 words. Current x86 hardware supports
up to 32 ZMM registers. For ZMM registers from ZMM0 to ZMM15, they are
assembled from three parts: XMM (the lower 2 u64 words),
YMMH (the middle 2 u64 words), and ZMMH (the upper 4 u64 words). The
perf_simd_reg_value() function is responsible for assembling these three
parts into a complete ZMM register for output to userspace.

For ZMM registers ZMM16 to ZMM31, each register can be read as a whole
and directly outputted to userspace.

Additionally, sample_simd_vec_reg_qwords should be set to 8 to indicate
ZMM sampling.

ZMM 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                | 16 +++++++++++++
 arch/x86/events/perf_event.h          | 33 +++++++++++++++++++++++++++
 arch/x86/include/asm/perf_event.h     |  8 +++++++
 arch/x86/include/uapi/asm/perf_regs.h |  8 +++++--
 arch/x86/kernel/perf_regs.c           | 16 ++++++++++++-
 5 files changed, 78 insertions(+), 3 deletions(-)

diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c
index 10d90050def3..ef0e238a4678 100644
--- a/arch/x86/events/core.c
+++ b/arch/x86/events/core.c
@@ -729,6 +729,12 @@ int x86_pmu_hw_config(struct perf_event *event)
 			if (event_needs_ymm(event) &&
 			    !(x86_pmu.ext_regs_mask & XFEATURE_MASK_YMM))
 				return -EINVAL;
+			if (event_needs_low16_zmm(event) &&
+			    !(x86_pmu.ext_regs_mask & XFEATURE_MASK_ZMM_Hi256))
+				return -EINVAL;
+			if (event_needs_high16_zmm(event) &&
+			    !(x86_pmu.ext_regs_mask & XFEATURE_MASK_Hi16_ZMM))
+				return -EINVAL;
 		}
 	}
 
@@ -1774,6 +1780,8 @@ void x86_pmu_clear_perf_regs(struct pt_regs *regs)
 	perf_regs->abi = PERF_SAMPLE_REGS_ABI_NONE;
 	perf_regs->xmm_regs = NULL;
 	perf_regs->ymmh_regs = NULL;
+	perf_regs->zmmh_regs = NULL;
+	perf_regs->h16zmm_regs = NULL;
 }
 
 static void update_perf_regs(struct x86_perf_regs *perf_regs,
@@ -1791,6 +1799,10 @@ static void update_perf_regs(struct x86_perf_regs *perf_regs,
 		perf_regs->xmm_space = xsave->i387.xmm_space;
 	if (mask & XFEATURE_MASK_YMM)
 		perf_regs->ymmh = get_xsave_addr(xsave, XFEATURE_YMM);
+	if (mask & XFEATURE_MASK_ZMM_Hi256)
+		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);
 }
 
 /*
@@ -1984,6 +1996,10 @@ static void x86_pmu_sample_xregs(struct perf_event *event,
 		mask |= XFEATURE_MASK_SSE;
 	if (event_needs_ymm(event))
 		mask |= XFEATURE_MASK_YMM;
+	if (event_needs_low16_zmm(event))
+		mask |= XFEATURE_MASK_ZMM_Hi256;
+	if (event_needs_high16_zmm(event))
+		mask |= XFEATURE_MASK_Hi16_ZMM;
 
 	mask &= x86_pmu.ext_regs_mask;
 	if ((sample_type & PERF_SAMPLE_REGS_USER) && data->regs_user.regs) {
diff --git a/arch/x86/events/perf_event.h b/arch/x86/events/perf_event.h
index 13f1f34ff8b0..01414b3a88fd 100644
--- a/arch/x86/events/perf_event.h
+++ b/arch/x86/events/perf_event.h
@@ -176,6 +176,39 @@ static inline bool event_needs_ymm(struct perf_event *event)
 	return false;
 }
 
+static inline bool event_needs_low16_zmm(struct perf_event *event)
+{
+	if (!(event->attr.sample_type &
+	      (PERF_SAMPLE_REGS_INTR | PERF_SAMPLE_REGS_USER)))
+		return false;
+
+	if (event->attr.sample_simd_regs_enabled &&
+	    event->attr.sample_simd_vec_reg_qwords >= PERF_X86_ZMM_QWORDS)
+		return true;
+
+	return false;
+}
+
+static inline bool event_needs_high16_zmm(struct perf_event *event)
+{
+	if (!(event->attr.sample_type &
+	      (PERF_SAMPLE_REGS_INTR | PERF_SAMPLE_REGS_USER)))
+		return false;
+
+	if (!event->attr.sample_simd_regs_enabled)
+		return false;
+
+	if ((event->attr.sample_type & PERF_SAMPLE_REGS_INTR) &&
+	    (fls64(event->attr.sample_simd_vec_reg_intr) > PERF_X86_H16ZMM_BASE))
+		return true;
+
+	if ((event->attr.sample_type & PERF_SAMPLE_REGS_USER) &&
+	    (fls64(event->attr.sample_simd_vec_reg_user) > PERF_X86_H16ZMM_BASE))
+		return true;
+
+	return false;
+}
+
 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 da77845e1f02..75394c4e8bc3 100644
--- a/arch/x86/include/asm/perf_event.h
+++ b/arch/x86/include/asm/perf_event.h
@@ -737,6 +737,14 @@ struct x86_perf_regs {
 		u64	*ymmh_regs;
 		struct ymmh_struct *ymmh;
 	};
+	union {
+		u64	*zmmh_regs;
+		struct avx_512_zmm_uppers_state *zmmh;
+	};
+	union {
+		u64	*h16zmm_regs;
+		struct avx_512_hi16_state *h16zmm;
+	};
 };
 
 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 d544f6d79871..b88d0b6822fd 100644
--- a/arch/x86/include/uapi/asm/perf_regs.h
+++ b/arch/x86/include/uapi/asm/perf_regs.h
@@ -60,16 +60,20 @@ enum perf_event_x86_regs {
 enum {
 	PERF_X86_SIMD_XMM_REGS      = 16,
 	PERF_X86_SIMD_YMM_REGS      = 16,
-	PERF_X86_SIMD_VEC_REGS_MAX  = PERF_X86_SIMD_YMM_REGS,
+	PERF_X86_SIMD_ZMM_REGS      = 32,
+	PERF_X86_SIMD_VEC_REGS_MAX  = PERF_X86_SIMD_ZMM_REGS,
 };
 
 #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_XMM_QWORDS      = 2,
 	PERF_X86_YMM_QWORDS      = 4,
-	PERF_X86_SIMD_QWORDS_MAX = PERF_X86_YMM_QWORDS,
+	PERF_X86_ZMM_QWORDS      = 8,
+	PERF_X86_SIMD_QWORDS_MAX = PERF_X86_ZMM_QWORDS,
 };
 
 #endif /* _ASM_X86_PERF_REGS_H */
diff --git a/arch/x86/kernel/perf_regs.c b/arch/x86/kernel/perf_regs.c
index 316d18c13c02..b4a584057fe4 100644
--- a/arch/x86/kernel/perf_regs.c
+++ b/arch/x86/kernel/perf_regs.c
@@ -78,6 +78,7 @@ u64 perf_reg_value(struct pt_regs *regs, int idx)
 }
 
 #define PERF_X86_YMMH_QWORDS	(PERF_X86_YMM_QWORDS / 2)
+#define PERF_X86_ZMMH_QWORDS	(PERF_X86_ZMM_QWORDS / 2)
 
 u64 perf_simd_reg_value(struct pt_regs *regs, int idx,
 			u16 qwords_idx, bool pred)
@@ -95,6 +96,13 @@ u64 perf_simd_reg_value(struct pt_regs *regs, int idx,
 			 qwords_idx >= PERF_X86_SIMD_QWORDS_MAX))
 		return 0;
 
+	if (idx >= PERF_X86_H16ZMM_BASE) {
+		if (!perf_regs->h16zmm_regs)
+			return 0;
+		return perf_regs->h16zmm_regs[(idx - PERF_X86_H16ZMM_BASE) *
+					PERF_X86_ZMM_QWORDS + qwords_idx];
+	}
+
 	if (qwords_idx < PERF_X86_XMM_QWORDS) {
 		if (!perf_regs->xmm_regs)
 			return 0;
@@ -105,6 +113,11 @@ u64 perf_simd_reg_value(struct pt_regs *regs, int idx,
 			return 0;
 		return perf_regs->ymmh_regs[idx * PERF_X86_YMMH_QWORDS +
 					    qwords_idx - PERF_X86_XMM_QWORDS];
+	} else if (qwords_idx < PERF_X86_ZMM_QWORDS) {
+		if (!perf_regs->zmmh_regs)
+			return 0;
+		return perf_regs->zmmh_regs[idx * PERF_X86_ZMMH_QWORDS +
+					    qwords_idx - PERF_X86_YMM_QWORDS];
 	}
 
 	return 0;
@@ -126,7 +139,8 @@ int perf_simd_reg_validate(u64 sample_type, u16 simd_enabled,
 
 	if (vec_qwords) {
 		if (vec_qwords != PERF_X86_XMM_QWORDS &&
-		    vec_qwords != PERF_X86_YMM_QWORDS)
+		    vec_qwords != PERF_X86_YMM_QWORDS &&
+		    vec_qwords != PERF_X86_ZMM_QWORDS)
 			return -EINVAL;
 		if (!vec_mask_intr && !vec_mask_user)
 			return -EINVAL;
-- 
2.34.1