riscv: add ISA extension parsing for bfloat16 ISA extension

Add parsing for Zfbmin, Zvfbfmin, Zvfbfwma ISA extension which
were ratified in 4dc23d62 ("Added Chapter title to BF16") of
the riscv-isa-manual.

Signed-off-by: Inochi Amaoto <inochiama@gmail.com>
Reviewed-by: Clément Léger <cleger@rivosinc.com>
Link: https://lore.kernel.org/r/20250213003849.147358-3-inochiama@gmail.com
Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>

diff --git a/arch/riscv/include/asm/hwcap.h b/arch/riscv/include/asm/hwcap.h
index 869da08..14cc29f 100644 (file)
--- a/arch/riscv/include/asm/hwcap.h
+++ b/arch/riscv/include/asm/hwcap.h
@@ -100,6 +100,9 @@
 #define RISCV_ISA_EXT_ZICCRSE          91
 #define RISCV_ISA_EXT_SVADE            92
 #define RISCV_ISA_EXT_SVADU            93
+#define RISCV_ISA_EXT_ZFBFMIN          94
+#define RISCV_ISA_EXT_ZVFBFMIN         95
+#define RISCV_ISA_EXT_ZVFBFWMA         96
 
 #define RISCV_ISA_EXT_XLINUXENVCFG     127
 

diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
index c0916ed..4002145 100644 (file)
--- a/arch/riscv/kernel/cpufeature.c
+++ b/arch/riscv/kernel/cpufeature.c
@@ -76,6 +76,15 @@ bool __riscv_isa_extension_available(const unsigned long *isa_bitmap, unsigned i
 }
 EXPORT_SYMBOL_GPL(__riscv_isa_extension_available);
 
+static int riscv_ext_f_depends(const struct riscv_isa_ext_data *data,
+                              const unsigned long *isa_bitmap)
+{
+       if (__riscv_isa_extension_available(isa_bitmap, RISCV_ISA_EXT_f))
+               return 0;
+
+       return -EPROBE_DEFER;
+}
+
 static int riscv_ext_zicbom_validate(const struct riscv_isa_ext_data *data,
                                     const unsigned long *isa_bitmap)
 {
@@ -136,6 +145,28 @@ static int riscv_ext_zcf_validate(const struct riscv_isa_ext_data *data,
        return -EPROBE_DEFER;
 }
 
+static int riscv_vector_f_validate(const struct riscv_isa_ext_data *data,
+                                  const unsigned long *isa_bitmap)
+{
+       if (!IS_ENABLED(CONFIG_RISCV_ISA_V))
+               return -EINVAL;
+
+       if (__riscv_isa_extension_available(isa_bitmap, RISCV_ISA_EXT_ZVE32F))
+               return 0;
+
+       return -EPROBE_DEFER;
+}
+
+static int riscv_ext_zvfbfwma_validate(const struct riscv_isa_ext_data *data,
+                                      const unsigned long *isa_bitmap)
+{
+       if (__riscv_isa_extension_available(isa_bitmap, RISCV_ISA_EXT_ZFBFMIN) &&
+           __riscv_isa_extension_available(isa_bitmap, RISCV_ISA_EXT_ZVFBFMIN))
+               return 0;
+
+       return -EPROBE_DEFER;
+}
+
 static int riscv_ext_svadu_validate(const struct riscv_isa_ext_data *data,
                                    const unsigned long *isa_bitmap)
 {
@@ -341,6 +372,7 @@ const struct riscv_isa_ext_data riscv_isa_ext[] = {
        __RISCV_ISA_EXT_DATA(zacas, RISCV_ISA_EXT_ZACAS),
        __RISCV_ISA_EXT_DATA(zawrs, RISCV_ISA_EXT_ZAWRS),
        __RISCV_ISA_EXT_DATA(zfa, RISCV_ISA_EXT_ZFA),
+       __RISCV_ISA_EXT_DATA_VALIDATE(zfbfmin, RISCV_ISA_EXT_ZFBFMIN, riscv_ext_f_depends),
        __RISCV_ISA_EXT_DATA(zfh, RISCV_ISA_EXT_ZFH),
        __RISCV_ISA_EXT_DATA(zfhmin, RISCV_ISA_EXT_ZFHMIN),
        __RISCV_ISA_EXT_DATA(zca, RISCV_ISA_EXT_ZCA),
@@ -373,6 +405,9 @@ const struct riscv_isa_ext_data riscv_isa_ext[] = {
        __RISCV_ISA_EXT_SUPERSET(zve64d, RISCV_ISA_EXT_ZVE64D, riscv_zve64d_exts),
        __RISCV_ISA_EXT_SUPERSET(zve64f, RISCV_ISA_EXT_ZVE64F, riscv_zve64f_exts),
        __RISCV_ISA_EXT_SUPERSET(zve64x, RISCV_ISA_EXT_ZVE64X, riscv_zve64x_exts),
+       __RISCV_ISA_EXT_DATA_VALIDATE(zvfbfmin, RISCV_ISA_EXT_ZVFBFMIN, riscv_vector_f_validate),
+       __RISCV_ISA_EXT_DATA_VALIDATE(zvfbfwma, RISCV_ISA_EXT_ZVFBFWMA,
+                                     riscv_ext_zvfbfwma_validate),
        __RISCV_ISA_EXT_DATA(zvfh, RISCV_ISA_EXT_ZVFH),
        __RISCV_ISA_EXT_DATA(zvfhmin, RISCV_ISA_EXT_ZVFHMIN),
        __RISCV_ISA_EXT_DATA(zvkb, RISCV_ISA_EXT_ZVKB),