[PATCH RFC v2 04/16] RISC-V: add Zbkb extension detection

[Heiko Stuebner <heiko@sntech.de>]

From: Heiko Stuebner <heiko.stuebner@vrull.eu>

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@vrull.eu>
---
 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 8673c2146d20..23427b9ed1e6 100644
--- a/arch/riscv/include/asm/hwcap.h
+++ b/arch/riscv/include/asm/hwcap.h
@@ -61,6 +61,7 @@ enum riscv_isa_ext_id {
 	RISCV_ISA_EXT_SVPBMT,
 	RISCV_ISA_EXT_ZBB,
 	RISCV_ISA_EXT_ZBC,
+	RISCV_ISA_EXT_ZBKB,
 	RISCV_ISA_EXT_ZICBOM,
 	RISCV_ISA_EXT_ZIHINTPAUSE,
 	RISCV_ISA_EXT_ID_MAX
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 696b39de7e09..8f5434993128 100644
--- a/arch/riscv/kernel/cpufeature.c
+++ b/arch/riscv/kernel/cpufeature.c
@@ -235,6 +235,7 @@ 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