[v5,06/21] RISC-V: Add Smcntrpmf extension parsing

Commit Message

Atish Patra March 27, 2025, 7:35 p.m. UTC

Smcntrpmf extension allows M-mode to enable privilege mode filtering
for cycle/instret counters. However, the cyclecfg/instretcfg CSRs are
only available only in Ssccfg only Smcntrpmf is present.

That's why, kernel needs to detect presence of Smcntrpmf extension and
enable privilege mode filtering for cycle/instret counters.

Reviewed-by: Clément Léger <[e-mail]>
Signed-off-by: Atish Patra <[e-mail]>
---
 arch/riscv/include/asm/hwcap.h | 1 +
 arch/riscv/kernel/cpufeature.c | 1 +
 2 files changed, 2 insertions(+)

Patch

diff --git a/arch/riscv/include/asm/hwcap.h b/arch/riscv/include/asm/hwcap.h
index 3d6e706fc5b2..b4eddcb57842 100644
--- a/arch/riscv/include/asm/hwcap.h
+++ b/arch/riscv/include/asm/hwcap.h
@@ -102,6 +102,7 @@ 
 #define RISCV_ISA_EXT_SVADU		93
 #define RISCV_ISA_EXT_SSCSRIND		94
 #define RISCV_ISA_EXT_SMCSRIND		95
+#define RISCV_ISA_EXT_SMCNTRPMF         96
 
 #define RISCV_ISA_EXT_XLINUXENVCFG	127
 
diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
index eddbab038301..e3e40cfe7967 100644
--- a/arch/riscv/kernel/cpufeature.c
+++ b/arch/riscv/kernel/cpufeature.c
@@ -394,6 +394,7 @@  const struct riscv_isa_ext_data riscv_isa_ext[] = {
 	__RISCV_ISA_EXT_BUNDLE(zvksg, riscv_zvksg_bundled_exts),
 	__RISCV_ISA_EXT_DATA(zvkt, RISCV_ISA_EXT_ZVKT),
 	__RISCV_ISA_EXT_DATA(smaia, RISCV_ISA_EXT_SMAIA),
+	__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),