[PATCH v5 1/4] RISC-V: add Zbc extension detection

Heiko Stuebner
2023-06-12T21:08:50Z

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

Add handling for Zbc extension.

Zbc provides instruction for carry-less multiplication.

Signed-off-by: Heiko Stuebner <heiko.stuebner@vrull.eu>
---
arch/riscv/Kconfig | 22 ++++++++++++++++++++++
arch/riscv/include/asm/hwcap.h | 1 +
arch/riscv/kernel/cpu.c | 1 +
arch/riscv/kernel/cpufeature.c | 1 +
4 files changed, 25 insertions(+)

diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index a3d54cd14fca..754cd154eca5 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -523,6 +523,28 @@ config RISCV_ISA_ZBB

If you don't know what to do here, say Y.

+config TOOLCHAIN_HAS_ZBC
+ bool
+ default y
+ depends on !64BIT || $(cc-option,-mabi=lp64 -march=rv64ima_zbc)
+ depends on !32BIT || $(cc-option,-mabi=ilp32 -march=rv32ima_zbc)
+ depends on LLD_VERSION >= 150000 || LD_VERSION >= 23900
+ depends on AS_IS_GNU
+
+config RISCV_ISA_ZBC
+ bool "Zbc extension support for bit manipulation instructions"
+ depends on TOOLCHAIN_HAS_ZBC
+ depends on !XIP_KERNEL && MMU
+ default y
+ help
+ Adds support to dynamically detect the presence of the ZBC
+ extension (carry-less multiplication) and enable its usage.
+
+ The Zbc extension provides instructions clmul, clmulh and clmulr
+ to accelerate carry-less multiplications.
+
+ If you don't know what to do here, say Y.
+
config RISCV_ISA_ZICBOM
bool "Zicbom extension support for non-coherent DMA operation"
depends on MMU
diff --git a/arch/riscv/include/asm/hwcap.h b/arch/riscv/include/asm/hwcap.h
index e6c288ac4581..e48ac52b9174 100644
--- a/arch/riscv/include/asm/hwcap.h
+++ b/arch/riscv/include/asm/hwcap.h
@@ -47,6 +47,7 @@
#define RISCV_ISA_EXT_ZICBOZ 34
#define RISCV_ISA_EXT_SMAIA 35
#define RISCV_ISA_EXT_SSAIA 36
+#define RISCV_ISA_EXT_ZBC 37

#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 637263f9a7b9..bbff98d4712a 100644
--- a/arch/riscv/kernel/cpu.c
+++ b/arch/riscv/kernel/cpu.c
@@ -188,6 +188,7 @@ static struct riscv_isa_ext_data isa_ext_arr[] = {
__RISCV_ISA_EXT_DATA(zicboz, RISCV_ISA_EXT_ZICBOZ),
__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(smaia, RISCV_ISA_EXT_SMAIA),
__RISCV_ISA_EXT_DATA(ssaia, RISCV_ISA_EXT_SSAIA),
__RISCV_ISA_EXT_DATA(sscofpmf, RISCV_ISA_EXT_SSCOFPMF),
diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
index de2d16300f69..f46281f1e439 100644
--- a/arch/riscv/kernel/cpufeature.c
+++ b/arch/riscv/kernel/cpufeature.c
@@ -261,6 +261,7 @@ void __init riscv_fill_hwcap(void)
SET_ISA_EXT_MAP("svnapot", RISCV_ISA_EXT_SVNAPOT);
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("zicbom", RISCV_ISA_EXT_ZICBOM);
SET_ISA_EXT_MAP("zicboz", RISCV_ISA_EXT_ZICBOZ);
SET_ISA_EXT_MAP("zihintpause", RISCV_ISA_EXT_ZIHINTPAUSE);
--
2.39.0