[PATCH RFC 05/12] 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 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 995462a0de86..f9f361285b04 100644
--- a/arch/riscv/kernel/cpu.c
+++ b/arch/riscv/kernel/cpu.c
@@ -187,6 +187,7 @@ arch_initcall(riscv_cpuinfo_init);
 static struct riscv_isa_ext_data isa_ext_arr[] = {
 	__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(zicbom, RISCV_ISA_EXT_ZICBOM),
 	__RISCV_ISA_EXT_DATA(zihintpause, RISCV_ISA_EXT_ZIHINTPAUSE),
 	__RISCV_ISA_EXT_DATA(sscofpmf, RISCV_ISA_EXT_SSCOFPMF),
diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
index ba74f3fa2310..695dfd732483 100644
--- a/arch/riscv/kernel/cpufeature.c
+++ b/arch/riscv/kernel/cpufeature.c
@@ -236,6 +236,7 @@ printk("!!!! isa-string: %s\n\n\n", isa);
 				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