linux-kernel - [PATCH v4 2/3] riscv: add ISA extension parsing for bfloat16 ISA extension

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Message-ID: <20250213003849.147358-3-inochiama@gmail.com>
Date: Thu, 13 Feb 2025 08:38:46 +0800
From: Inochi Amaoto <inochiama@...il.com>
To: Jonathan Corbet <corbet@....net>,
	Paul Walmsley <paul.walmsley@...ive.com>,
	Palmer Dabbelt <palmer@...belt.com>,
	Albert Ou <aou@...s.berkeley.edu>,
	Rob Herring <robh@...nel.org>,
	Krzysztof Kozlowski <krzk+dt@...nel.org>,
	Conor Dooley <conor+dt@...nel.org>,
	Clément Léger <cleger@...osinc.com>,
	Charlie Jenkins <charlie@...osinc.com>,
	Evan Green <evan@...osinc.com>,
	Inochi Amaoto <inochiama@...il.com>,
	Andrew Jones <ajones@...tanamicro.com>,
	Jesse Taube <jesse@...osinc.com>,
	Andy Chiu <andybnac@...il.com>,
	Alexandre Ghiti <alexghiti@...osinc.com>,
	Yong-Xuan Wang <yongxuan.wang@...ive.com>,
	Yu Chien Peter Lin <peterlin@...estech.com>,
	Samuel Holland <samuel.holland@...ive.com>
Cc: linux-doc@...r.kernel.org,
	linux-riscv@...ts.infradead.org,
	linux-kernel@...r.kernel.org,
	devicetree@...r.kernel.org,
	Yixun Lan <dlan@...too.org>,
	Longbin Li <looong.bin@...il.com>
Subject: [PATCH v4 2/3] 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@...il.com>
Reviewed-by: Clément Léger <cleger@...osinc.com>
---
 arch/riscv/include/asm/hwcap.h |  3 +++
 arch/riscv/kernel/cpufeature.c | 35 ++++++++++++++++++++++++++++++++++
 2 files changed, 38 insertions(+)

diff --git a/arch/riscv/include/asm/hwcap.h b/arch/riscv/include/asm/hwcap.h
index 869da082252a..14cc29f2a723 100644
--- 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 c6ba750536c3..37fb6b07281e 100644
--- a/arch/riscv/kernel/cpufeature.c
+++ b/arch/riscv/kernel/cpufeature.c
@@ -80,6 +80,15 @@ 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)
 {
@@ -140,6 +149,28 @@ 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)
 {
@@ -345,6 +376,7 @@ 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),
@@ -377,6 +409,9 @@ 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),
-- 
2.48.1