[PATCH v8 09/22] RISC-V: Add Ssccfg/Smcdeleg ISA extension definition and parsing

[Atish Patra <atish.patra@linux.dev>]

From: Atish Patra <atishp@rivosinc.com>

Smcdeleg extension allows the M-mode to delegate selected counters
to S-mode so that it can access those counters and correpsonding
hpmevent CSRs without M-mode.

Ssccfg (‘Ss’ for Privileged architecture and Supervisor-level
extension, ‘ccfg’ for Counter Configuration) provides access to
delegated counters and new supervisor-level state.

This patch just enables these definitions and enable parsing.

Signed-off-by: Atish Patra <atishp@rivosinc.com>
---
 arch/riscv/include/asm/hwcap.h |  2 ++
 arch/riscv/kernel/cpufeature.c | 24 ++++++++++++++++++++++++
 2 files changed, 26 insertions(+)

diff --git a/arch/riscv/include/asm/hwcap.h b/arch/riscv/include/asm/hwcap.h
index 51ad55b9677a..089353b250b0 100644
--- a/arch/riscv/include/asm/hwcap.h
+++ b/arch/riscv/include/asm/hwcap.h
@@ -115,6 +115,8 @@
 #define RISCV_ISA_EXT_SSCSRIND		106
 #define RISCV_ISA_EXT_SMCSRIND		107
 #define RISCV_ISA_EXT_SMCNTRPMF		108
+#define RISCV_ISA_EXT_SSCCFG		109
+#define RISCV_ISA_EXT_SMCDELEG		110
 
 #define RISCV_ISA_EXT_XLINUXENVCFG	127
 
diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
index 1452521d740a..1fe647e03515 100644
--- a/arch/riscv/kernel/cpufeature.c
+++ b/arch/riscv/kernel/cpufeature.c
@@ -330,6 +330,27 @@ static const unsigned int riscv_a_exts[] = {
 	RISCV_ISA_EXT_ZKNE,	\
 	RISCV_ISA_EXT_ZKNH
 
+static int riscv_ext_smcdeleg_validate(const struct riscv_isa_ext_data *data,
+				       const unsigned long *isa_bitmap)
+{
+	if (__riscv_isa_extension_available(isa_bitmap, RISCV_ISA_EXT_SSCSRIND) &&
+	    __riscv_isa_extension_available(isa_bitmap, RISCV_ISA_EXT_ZIHPM) &&
+	    __riscv_isa_extension_available(isa_bitmap, RISCV_ISA_EXT_ZICNTR))
+		return 0;
+
+	return -EPROBE_DEFER;
+}
+
+static int riscv_ext_ssccfg_validate(const struct riscv_isa_ext_data *data,
+				     const unsigned long *isa_bitmap)
+{
+	if (!riscv_ext_smcdeleg_validate(data, isa_bitmap) &&
+	    __riscv_isa_extension_available(isa_bitmap, RISCV_ISA_EXT_SMCDELEG))
+		return 0;
+
+	return -EPROBE_DEFER;
+}
+
 static const unsigned int riscv_zk_bundled_exts[] = {
 	RISCV_ISA_EXT_ZKN,
 	RISCV_ISA_EXT_ZKR,
@@ -576,12 +597,15 @@ const struct riscv_isa_ext_data riscv_isa_ext[] = {
 	__RISCV_ISA_EXT_BUNDLE_VALIDATE(zvksg, riscv_zvksg_bundled_exts, riscv_ext_vector_crypto_validate),
 	__RISCV_ISA_EXT_DATA_VALIDATE(zvkt, RISCV_ISA_EXT_ZVKT, riscv_ext_vector_crypto_validate),
 	__RISCV_ISA_EXT_DATA(smaia, RISCV_ISA_EXT_SMAIA),
+	__RISCV_ISA_EXT_DATA_VALIDATE(smcdeleg, RISCV_ISA_EXT_SMCDELEG,
+				      riscv_ext_smcdeleg_validate),
 	__RISCV_ISA_EXT_DATA(smcntrpmf, RISCV_ISA_EXT_SMCNTRPMF),
 	__RISCV_ISA_EXT_DATA(smcsrind, RISCV_ISA_EXT_SMCSRIND),
 	__RISCV_ISA_EXT_DATA(smmpm, RISCV_ISA_EXT_SMMPM),
 	__RISCV_ISA_EXT_SUPERSET(smnpm, RISCV_ISA_EXT_SMNPM, riscv_xlinuxenvcfg_exts),
 	__RISCV_ISA_EXT_DATA(smstateen, RISCV_ISA_EXT_SMSTATEEN),
 	__RISCV_ISA_EXT_DATA(ssaia, RISCV_ISA_EXT_SSAIA),
+	__RISCV_ISA_EXT_DATA_VALIDATE(ssccfg, RISCV_ISA_EXT_SSCCFG, riscv_ext_ssccfg_validate),
 	__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),

-- 
2.53.0-Meta