[RFC PATCH v2 2/4] riscv: Add detection for Sspesa and Ssplcofi extensions

[Mayuresh Chitale]

Add ISA extension detection for the RISC-V Performance Event Sampling
extensions Sspesa (Precise Event Sample Attribution) and Ssplcofi
(Precise Local Counter Overflow Interrupt).

Ssplcofi requires Sspesa, so validate that Sspesa is present before
enabling Ssplcofi.

Signed-off-by: Mayuresh Chitale <mayuresh.chitale@xxxxxxxxxxxxxxxx>

diff --git a/arch/riscv/include/asm/csr.h b/arch/riscv/include/asm/csr.h
index 621f84d1898f..220d1dfab89e 100644
--- a/arch/riscv/include/asm/csr.h
+++ b/arch/riscv/include/asm/csr.h
@@ -350,6 +350,18 @@
 
 #define CSR_SCOUNTOVF		0xda0
 
+/* Temporary addresses for Sspesa (Precise Event Sample Attribution) CSRs. */
+#define CSR_SHPMSPC		0x5d0
+#define CSR_SHPMSDATA		0x5d1
+
+/* shpmsdata fields */
+#define SHPMSDATA_CNTRID	GENMASK(4, 0)
+#define SHPMSDATA_MODE		GENMASK(6, 5)
+#define SHPMSDATA_V		BIT(7)
+#define SHPMSDATA_METADATA_SHIFT	8
+#define SHPMSDATA_MODE_U	0
+#define SHPMSDATA_MODE_S	1
+
 #define CSR_SSTATUS		0x100
 #define CSR_SIE			0x104
 #define CSR_STVEC		0x105
diff --git a/arch/riscv/include/asm/hwcap.h b/arch/riscv/include/asm/hwcap.h
index f8db798b2654..030a946c73ef 100644
--- a/arch/riscv/include/asm/hwcap.h
+++ b/arch/riscv/include/asm/hwcap.h
@@ -122,6 +122,8 @@
 #define RISCV_ISA_EXT_ZICCAMOA		113
 #define RISCV_ISA_EXT_ZICCIF		114
 #define RISCV_ISA_EXT_ZA64RS		115
+#define RISCV_ISA_EXT_SSPESA		116
+#define RISCV_ISA_EXT_SSPLCOFI		117
 
 #define RISCV_ISA_EXT_XLINUXENVCFG	127
 
diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
index 7329792978cc..46405bf2dfea 100644
--- a/arch/riscv/kernel/cpufeature.c
+++ b/arch/riscv/kernel/cpufeature.c
@@ -287,6 +287,24 @@ static int riscv_ext_zvfbfwma_validate(const struct riscv_isa_ext_data *data,
 	return -EPROBE_DEFER;
 }
 
+static int riscv_ext_sspesa_validate(const struct riscv_isa_ext_data *data,
+				     const unsigned long *isa_bitmap)
+{
+	if (__riscv_isa_extension_available(isa_bitmap, RISCV_ISA_EXT_SSCOFPMF))
+		return 0;
+
+	return -EPROBE_DEFER;
+}
+
+static int riscv_ext_ssplcofi_validate(const struct riscv_isa_ext_data *data,
+				       const unsigned long *isa_bitmap)
+{
+	if (__riscv_isa_extension_available(isa_bitmap, RISCV_ISA_EXT_SSPESA))
+		return 0;
+
+	return -EPROBE_DEFER;
+}
+
 static int riscv_ext_svadu_validate(const struct riscv_isa_ext_data *data,
 				    const unsigned long *isa_bitmap)
 {
@@ -631,6 +649,9 @@ const struct riscv_isa_ext_data riscv_isa_ext[] = {
 	__RISCV_ISA_EXT_DATA(sscofpmf, RISCV_ISA_EXT_SSCOFPMF),
 	__RISCV_ISA_EXT_DATA(sscsrind, RISCV_ISA_EXT_SSCSRIND),
 	__RISCV_ISA_EXT_SUPERSET(ssnpm, RISCV_ISA_EXT_SSNPM, riscv_xlinuxenvcfg_exts),
+	__RISCV_ISA_EXT_DATA_VALIDATE(sspesa, RISCV_ISA_EXT_SSPESA, riscv_ext_sspesa_validate),
+	__RISCV_ISA_EXT_DATA_VALIDATE(ssplcofi, RISCV_ISA_EXT_SSPLCOFI,
+				      riscv_ext_ssplcofi_validate),
 	__RISCV_ISA_EXT_DATA(ssqosid, RISCV_ISA_EXT_SSQOSID),
 	__RISCV_ISA_EXT_DATA(sstc, RISCV_ISA_EXT_SSTC),
 	__RISCV_ISA_EXT_DATA(svade, RISCV_ISA_EXT_SVADE),