[PATCH 8/9] riscv: hwprobe: export Zacas ISA extension

[Clément Léger]

Export Zacas ISA extension through hwprobe.

Signed-off-by: Clément Léger <cleger at rivosinc.com>
---
 Documentation/arch/riscv/hwprobe.rst  | 4 ++++
 arch/riscv/include/uapi/asm/hwprobe.h | 1 +
 arch/riscv/kernel/sys_riscv.c         | 1 +
 3 files changed, 6 insertions(+)

diff --git a/Documentation/arch/riscv/hwprobe.rst b/Documentation/arch/riscv/hwprobe.rst
index 9b19ca3433de..510e49878834 100644
--- a/Documentation/arch/riscv/hwprobe.rst
+++ b/Documentation/arch/riscv/hwprobe.rst
@@ -168,6 +168,10 @@ The following keys are defined:
   * :c:macro:`RISCV_HWPROBE_EXT_ZAM`: The Zam extension v0.1 is supported as
        defined in the RISC-V ISA manual.
 
+  * :c:macro:`RISCV_HWPROBE_EXT_ZACAS`: The Zacas extension is supported as
+       defined in the Atomic Compare-and-Swap (CAS) instructions manual starting
+       from commit 5059e0ca641c ("update to ratified").
+
 * :c:macro:`RISCV_HWPROBE_KEY_CPUPERF_0`: A bitmask that contains performance
   information about the selected set of processors.
 
diff --git a/arch/riscv/include/uapi/asm/hwprobe.h b/arch/riscv/include/uapi/asm/hwprobe.h
index 2350c45741a6..7ec4331122e7 100644
--- a/arch/riscv/include/uapi/asm/hwprobe.h
+++ b/arch/riscv/include/uapi/asm/hwprobe.h
@@ -58,6 +58,7 @@ struct riscv_hwprobe {
 #define		RISCV_HWPROBE_EXT_ZFA		(1ULL << 32)
 #define		RISCV_HWPROBE_EXT_ZTSO		(1ULL << 33)
 #define		RISCV_HWPROBE_EXT_ZAM		(1ULL << 34)
+#define		RISCV_HWPROBE_EXT_ZACAS		(1ULL << 35)
 #define RISCV_HWPROBE_KEY_CPUPERF_0	5
 #define		RISCV_HWPROBE_MISALIGNED_UNKNOWN	(0 << 0)
 #define		RISCV_HWPROBE_MISALIGNED_EMULATED	(1 << 0)
diff --git a/arch/riscv/kernel/sys_riscv.c b/arch/riscv/kernel/sys_riscv.c
index a8473d7f9d1e..abb0eea3ee08 100644
--- a/arch/riscv/kernel/sys_riscv.c
+++ b/arch/riscv/kernel/sys_riscv.c
@@ -176,6 +176,7 @@ static void hwprobe_isa_ext0(struct riscv_hwprobe *pair,
 		EXT_KEY(ZIHINTNTL);
 		EXT_KEY(ZTSO);
 		EXT_KEY(ZAM);
+		EXT_KEY(ZACAS);
 
 		if (has_vector()) {
 			EXT_KEY(ZVBB);
-- 
2.43.0