riscv: hwprobe: add zve Vector subextensions into hwprobe interface

The following Vector subextensions for "embedded" platforms are added
into RISCV_HWPROBE_KEY_IMA_EXT_0:
 - ZVE32X
 - ZVE32F
 - ZVE64X
 - ZVE64F
 - ZVE64D

Extensions ending with an X indicates that the platform doesn't have a
vector FPU.
Extensions ending with F/D mean that whether single (F) or double (D)
precision vector operation is supported.
The number 32 or 64 follows from ZVE tells the maximum element length.

Signed-off-by: Andy Chiu <andy.chiu@sifive.com>
Reviewed-by: Clément Léger <cleger@rivosinc.com>
Link: https://lore.kernel.org/r/20240510-zve-detection-v5-6-0711bdd26c12@sifive.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>

Author: AndybnACT

Documentation/arch/riscv/hwprobe.rst

@@ -192,6 +192,21 @@ The following keys are defined:
        supported as defined in the RISC-V ISA manual starting from commit
        d8ab5c78c207 ("Zihintpause is ratified").
 
+  * :c:macro:`RISCV_HWPROBE_EXT_ZVE32X`: The Vector sub-extension Zve32x is
+    supported, as defined by version 1.0 of the RISC-V Vector extension manual.
+
+  * :c:macro:`RISCV_HWPROBE_EXT_ZVE32F`: The Vector sub-extension Zve32f is
+    supported, as defined by version 1.0 of the RISC-V Vector extension manual.
+
+  * :c:macro:`RISCV_HWPROBE_EXT_ZVE64X`: The Vector sub-extension Zve64x is
+    supported, as defined by version 1.0 of the RISC-V Vector extension manual.
+
+  * :c:macro:`RISCV_HWPROBE_EXT_ZVE64F`: The Vector sub-extension Zve64f is
+    supported, as defined by version 1.0 of the RISC-V Vector extension manual.
+
+  * :c:macro:`RISCV_HWPROBE_EXT_ZVE64D`: The Vector sub-extension Zve64d is
+    supported, as defined by version 1.0 of the RISC-V Vector extension manual.
+
 * :c:macro:`RISCV_HWPROBE_KEY_CPUPERF_0`: A bitmask that contains performance
   information about the selected set of processors.
 

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

@@ -60,6 +60,11 @@ struct riscv_hwprobe {
 #define		RISCV_HWPROBE_EXT_ZACAS		(1ULL << 34)
 #define		RISCV_HWPROBE_EXT_ZICOND	(1ULL << 35)
 #define		RISCV_HWPROBE_EXT_ZIHINTPAUSE	(1ULL << 36)
+#define		RISCV_HWPROBE_EXT_ZVE32X	(1ULL << 37)
+#define		RISCV_HWPROBE_EXT_ZVE32F	(1ULL << 38)
+#define		RISCV_HWPROBE_EXT_ZVE64X	(1ULL << 39)
+#define		RISCV_HWPROBE_EXT_ZVE64F	(1ULL << 40)
+#define		RISCV_HWPROBE_EXT_ZVE64D	(1ULL << 41)
 #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

@@ -114,6 +114,11 @@ static void hwprobe_isa_ext0(struct riscv_hwprobe *pair,
 		EXT_KEY(ZIHINTPAUSE);
 
 		if (has_vector()) {
+			EXT_KEY(ZVE32X);
+			EXT_KEY(ZVE32F);
+			EXT_KEY(ZVE64X);
+			EXT_KEY(ZVE64F);
+			EXT_KEY(ZVE64D);
 			EXT_KEY(ZVBB);
 			EXT_KEY(ZVBC);
 			EXT_KEY(ZVKB);