riscv: hwprobe: Export Zalasr extension

Export the Zalasr extension to userspace using hwprobe.

Signed-off-by: Xu Lu <luxu.kernel@bytedance.com>
Link: https://patch.msgid.link/20251020042056.30283-4-luxu.kernel@bytedance.com
Signed-off-by: Paul Walmsley <pjw@kernel.org>

Documentation/arch/riscv/hwprobe.rst

@@ -249,6 +249,9 @@ The following keys are defined:
        defined in the in the RISC-V ISA manual starting from commit e87412e621f1
        ("integrate Zaamo and Zalrsc text (#1304)").
 
+  * :c:macro:`RISCV_HWPROBE_EXT_ZALASR`: The Zalasr extension is supported as
+       frozen at commit 194f0094 ("Version 0.9 for freeze") of riscv-zalasr.
+
   * :c:macro:`RISCV_HWPROBE_EXT_ZALRSC`: The Zalrsc extension is supported as
        defined in the in the RISC-V ISA manual starting from commit e87412e621f1
        ("integrate Zaamo and Zalrsc text (#1304)").
@@ -369,4 +372,4 @@ The following keys are defined:
 
     * :c:macro:`RISCV_HWPROBE_VENDOR_EXT_XSFVFWMACCQQQ`: The Xsfvfwmaccqqq
         vendor extension is supported in version 1.0 of Matrix Multiply Accumulate
-	Instruction Extensions Specification.
+	Instruction Extensions Specification.

arch/riscv/include/uapi/asm/hwprobe.h

@@ -82,6 +82,7 @@ struct riscv_hwprobe {
 #define		RISCV_HWPROBE_EXT_ZAAMO		(1ULL << 56)
 #define		RISCV_HWPROBE_EXT_ZALRSC	(1ULL << 57)
 #define		RISCV_HWPROBE_EXT_ZABHA		(1ULL << 58)
+#define		RISCV_HWPROBE_EXT_ZALASR	(1ULL << 59)
 #define RISCV_HWPROBE_KEY_CPUPERF_0	5
 #define		RISCV_HWPROBE_MISALIGNED_UNKNOWN	(0 << 0)
 #define		RISCV_HWPROBE_MISALIGNED_EMULATED	(1 << 0)

arch/riscv/kernel/sys_hwprobe.c

@@ -109,6 +109,7 @@ static void hwprobe_isa_ext0(struct riscv_hwprobe *pair,
 		EXT_KEY(ZAAMO);
 		EXT_KEY(ZABHA);
 		EXT_KEY(ZACAS);
+		EXT_KEY(ZALASR);
 		EXT_KEY(ZALRSC);
 		EXT_KEY(ZAWRS);
 		EXT_KEY(ZBA);