[Patch v9 15/24] perf/x86: Support YMM sampling using sample_simd_vec_reg_* fields

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

Support sampling of YMM registers via the sample_simd_vec_reg_* fields.

Each YMM register consists of 4 u64 words, assembled from two halves:
XMM (the lower 2 u64 words) and YMMH (the upper 2 u64 words). Although
both XMM and YMMH data can be retrieved with a single xsaves instruction,
they are stored in separate locations. The perf_simd_reg_value() function
is responsible for assembling these halves into a complete YMM register
for output to userspace.

Additionally, sample_simd_vec_reg_qwords should be set to 4 to indicate
YMM sampling.

YMM 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                |  8 ++++++++
 arch/x86/events/perf_event.h          | 13 +++++++++++++
 arch/x86/include/asm/perf_event.h     |  4 ++++
 arch/x86/include/uapi/asm/perf_regs.h |  6 ++++--
 arch/x86/kernel/perf_regs.c           | 10 +++++++++-
 5 files changed, 38 insertions(+), 3 deletions(-)

diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c
index 117d09fb9a05..10d90050def3 100644
--- a/arch/x86/events/core.c
+++ b/arch/x86/events/core.c
@@ -726,6 +726,9 @@ int x86_pmu_hw_config(struct perf_event *event)
 			if (event_needs_xmm(event) &&
 			    !(x86_pmu.ext_regs_mask & XFEATURE_MASK_SSE))
 				return -EINVAL;
+			if (event_needs_ymm(event) &&
+			    !(x86_pmu.ext_regs_mask & XFEATURE_MASK_YMM))
+				return -EINVAL;
 		}
 	}
 
@@ -1770,6 +1773,7 @@ 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;
 }
 
 static void update_perf_regs(struct x86_perf_regs *perf_regs,
@@ -1785,6 +1789,8 @@ static void update_perf_regs(struct x86_perf_regs *perf_regs,
 
 	if (mask & XFEATURE_MASK_SSE)
 		perf_regs->xmm_space = xsave->i387.xmm_space;
+	if (mask & XFEATURE_MASK_YMM)
+		perf_regs->ymmh = get_xsave_addr(xsave, XFEATURE_YMM);
 }
 
 /*
@@ -1976,6 +1982,8 @@ static void x86_pmu_sample_xregs(struct perf_event *event,
 
 	if (event_needs_xmm(event))
 		mask |= XFEATURE_MASK_SSE;
+	if (event_needs_ymm(event))
+		mask |= XFEATURE_MASK_YMM;
 
 	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 6b1b83c906eb..13f1f34ff8b0 100644
--- a/arch/x86/events/perf_event.h
+++ b/arch/x86/events/perf_event.h
@@ -163,6 +163,19 @@ static inline bool event_needs_xmm(struct perf_event *event)
 	return false;
 }
 
+static inline bool event_needs_ymm(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_YMM_QWORDS)
+		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 a2b2123d008e..da77845e1f02 100644
--- a/arch/x86/include/asm/perf_event.h
+++ b/arch/x86/include/asm/perf_event.h
@@ -733,6 +733,10 @@ struct x86_perf_regs {
 		u64	*xmm_regs;
 		u32	*xmm_space;	/* for xsaves */
 	};
+	union {
+		u64	*ymmh_regs;
+		struct ymmh_struct *ymmh;
+	};
 };
 
 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 edb35408e4cc..d544f6d79871 100644
--- a/arch/x86/include/uapi/asm/perf_regs.h
+++ b/arch/x86/include/uapi/asm/perf_regs.h
@@ -59,7 +59,8 @@ enum perf_event_x86_regs {
 
 enum {
 	PERF_X86_SIMD_XMM_REGS      = 16,
-	PERF_X86_SIMD_VEC_REGS_MAX  = PERF_X86_SIMD_XMM_REGS,
+	PERF_X86_SIMD_YMM_REGS      = 16,
+	PERF_X86_SIMD_VEC_REGS_MAX  = PERF_X86_SIMD_YMM_REGS,
 };
 
 #define PERF_X86_SIMD_VEC_MASK	__GENMASK_ULL(PERF_X86_SIMD_VEC_REGS_MAX - 1, 0)
@@ -67,7 +68,8 @@ enum {
 enum {
 	/* 1 qword = 8 bytes */
 	PERF_X86_XMM_QWORDS      = 2,
-	PERF_X86_SIMD_QWORDS_MAX = PERF_X86_XMM_QWORDS,
+	PERF_X86_YMM_QWORDS      = 4,
+	PERF_X86_SIMD_QWORDS_MAX = PERF_X86_YMM_QWORDS,
 };
 
 #endif /* _ASM_X86_PERF_REGS_H */
diff --git a/arch/x86/kernel/perf_regs.c b/arch/x86/kernel/perf_regs.c
index 8514baefb400..316d18c13c02 100644
--- a/arch/x86/kernel/perf_regs.c
+++ b/arch/x86/kernel/perf_regs.c
@@ -77,6 +77,8 @@ u64 perf_reg_value(struct pt_regs *regs, int idx)
 	return regs_get_register(regs, pt_regs_offset[idx]);
 }
 
+#define PERF_X86_YMMH_QWORDS	(PERF_X86_YMM_QWORDS / 2)
+
 u64 perf_simd_reg_value(struct pt_regs *regs, int idx,
 			u16 qwords_idx, bool pred)
 {
@@ -98,6 +100,11 @@ u64 perf_simd_reg_value(struct pt_regs *regs, int idx,
 			return 0;
 		return perf_regs->xmm_regs[idx * PERF_X86_XMM_QWORDS +
 					   qwords_idx];
+	} else if (qwords_idx < PERF_X86_YMM_QWORDS) {
+		if (!perf_regs->ymmh_regs)
+			return 0;
+		return perf_regs->ymmh_regs[idx * PERF_X86_YMMH_QWORDS +
+					    qwords_idx - PERF_X86_XMM_QWORDS];
 	}
 
 	return 0;
@@ -118,7 +125,8 @@ int perf_simd_reg_validate(u64 sample_type, u16 simd_enabled,
 		return 0;
 
 	if (vec_qwords) {
-		if (vec_qwords != PERF_X86_XMM_QWORDS)
+		if (vec_qwords != PERF_X86_XMM_QWORDS &&
+		    vec_qwords != PERF_X86_YMM_QWORDS)
 			return -EINVAL;
 		if (!vec_mask_intr && !vec_mask_user)
 			return -EINVAL;
-- 
2.34.1