[PATCH RFC v3 04/16] RISC-V: add Zbkb extension detection

[Heiko Stuebner]

From: Heiko Stuebner <heiko.stuebner@xxxxxxxx>

Add detection for Zbkb extension.

Zbkb is part of the set of scalar cryptography extensions and provides
bitmanip instructions for cryptography, with them being a "subset of the
Zbb extension particularly useful for cryptography".

Zbkb was ratified in january 2022.

Expect code using the extension to pre-encode zbkb instructions, so
don't introduce special toolchain requirements for now.

Signed-off-by: Heiko Stuebner <heiko.stuebner@xxxxxxxx>
---
 arch/riscv/include/asm/hwcap.h | 1 +
 arch/riscv/kernel/cpu.c        | 1 +
 arch/riscv/kernel/cpufeature.c | 1 +
 3 files changed, 3 insertions(+)

diff --git a/arch/riscv/include/asm/hwcap.h b/arch/riscv/include/asm/hwcap.h
index 92f234c6cb4c..b28548fb10f3 100644
--- a/arch/riscv/include/asm/hwcap.h
+++ b/arch/riscv/include/asm/hwcap.h
@@ -44,6 +44,7 @@
 #define RISCV_ISA_EXT_ZICBOM		31
 #define RISCV_ISA_EXT_ZIHINTPAUSE	32
 #define RISCV_ISA_EXT_ZBC		33
+#define RISCV_ISA_EXT_ZBKB		34
 
 #define RISCV_ISA_EXT_MAX		64
 #define RISCV_ISA_EXT_NAME_LEN_MAX	32
diff --git a/arch/riscv/kernel/cpu.c b/arch/riscv/kernel/cpu.c
index 5d47a0c75c69..6f65aac68018 100644
--- a/arch/riscv/kernel/cpu.c
+++ b/arch/riscv/kernel/cpu.c
@@ -189,6 +189,7 @@ static struct riscv_isa_ext_data isa_ext_arr[] = {
 	__RISCV_ISA_EXT_DATA(zihintpause, RISCV_ISA_EXT_ZIHINTPAUSE),
 	__RISCV_ISA_EXT_DATA(zbb, RISCV_ISA_EXT_ZBB),
 	__RISCV_ISA_EXT_DATA(zbc, RISCV_ISA_EXT_ZBC),
+	__RISCV_ISA_EXT_DATA(zbkb, RISCV_ISA_EXT_ZBKB),
 	__RISCV_ISA_EXT_DATA(sscofpmf, RISCV_ISA_EXT_SSCOFPMF),
 	__RISCV_ISA_EXT_DATA(sstc, RISCV_ISA_EXT_SSTC),
 	__RISCV_ISA_EXT_DATA(svinval, RISCV_ISA_EXT_SVINVAL),
diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
index c9099694b5bb..eb7be8e7f24e 100644
--- a/arch/riscv/kernel/cpufeature.c
+++ b/arch/riscv/kernel/cpufeature.c
@@ -229,6 +229,7 @@ void __init riscv_fill_hwcap(void)
 				SET_ISA_EXT_MAP("svpbmt", RISCV_ISA_EXT_SVPBMT);
 				SET_ISA_EXT_MAP("zbb", RISCV_ISA_EXT_ZBB);
 				SET_ISA_EXT_MAP("zbc", RISCV_ISA_EXT_ZBC);
+				SET_ISA_EXT_MAP("zbkb", RISCV_ISA_EXT_ZBKB);
 				SET_ISA_EXT_MAP("zicbom", RISCV_ISA_EXT_ZICBOM);
 				SET_ISA_EXT_MAP("zihintpause", RISCV_ISA_EXT_ZIHINTPAUSE);
 			}
-- 
2.39.0