Re: [PATCH v3 2/6] RISC-V: Detect Zicond from ISA string

From: Palmer Dabbelt
Date: Wed Oct 04 2023 - 10:18:28 EST


On Mon, 02 Oct 2023 20:52:22 PDT (-0700), apatel@xxxxxxxxxxxxxxxx wrote:
The RISC-V integer conditional (Zicond) operation extension defines
standard conditional arithmetic and conditional-select/move operations
which are inspired from the XVentanaCondOps extension. In fact, QEMU
RISC-V also has support for emulating Zicond extension.

Let us detect Zicond extension from ISA string available through
DT or ACPI.

Signed-off-by: Anup Patel <apatel@xxxxxxxxxxxxxxxx>
Reviewed-by: Andrew Jones <ajones@xxxxxxxxxxxxxxxx>
Reviewed-by: Conor Dooley <conor.dooley@xxxxxxxxxxxxx>
---
arch/riscv/include/asm/hwcap.h | 1 +
arch/riscv/kernel/cpufeature.c | 1 +
2 files changed, 2 insertions(+)

diff --git a/arch/riscv/include/asm/hwcap.h b/arch/riscv/include/asm/hwcap.h
index 0f520f7d058a..6fc51c1b34cf 100644
--- a/arch/riscv/include/asm/hwcap.h
+++ b/arch/riscv/include/asm/hwcap.h
@@ -59,6 +59,7 @@
#define RISCV_ISA_EXT_ZIFENCEI 41
#define RISCV_ISA_EXT_ZIHPM 42
#define RISCV_ISA_EXT_SMSTATEEN 43
+#define RISCV_ISA_EXT_ZICOND 44

#define RISCV_ISA_EXT_MAX 64

diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
index 3755a8c2a9de..e3803822ab5a 100644
--- a/arch/riscv/kernel/cpufeature.c
+++ b/arch/riscv/kernel/cpufeature.c
@@ -167,6 +167,7 @@ const struct riscv_isa_ext_data riscv_isa_ext[] = {
__RISCV_ISA_EXT_DATA(zicbom, RISCV_ISA_EXT_ZICBOM),
__RISCV_ISA_EXT_DATA(zicboz, RISCV_ISA_EXT_ZICBOZ),
__RISCV_ISA_EXT_DATA(zicntr, RISCV_ISA_EXT_ZICNTR),
+ __RISCV_ISA_EXT_DATA(zicond, RISCV_ISA_EXT_ZICOND),
__RISCV_ISA_EXT_DATA(zicsr, RISCV_ISA_EXT_ZICSR),
__RISCV_ISA_EXT_DATA(zifencei, RISCV_ISA_EXT_ZIFENCEI),
__RISCV_ISA_EXT_DATA(zihintpause, RISCV_ISA_EXT_ZIHINTPAUSE),

Acked-by: Palmer Dabbelt <palmer@xxxxxxxxxxxx>

Can we do a shared tag, though? These will conflict.