[PATCH v3 0/6] Add some validation for vector, vector crypto and fp stuff

[PATCH v3 0/6] Add some validation for vector, vector crypto and fp stuff

[Conor Dooley]

From: Conor Dooley <conor.dooley@microchip.com>

Yo,

This series is partly leveraging Clement's work adding a validate
callback in the extension detection code so that things like checking
for whether a vector crypto extension is usable can be done like:
	has_extension(<vector crypto>)
rather than
	has_vector() && has_extension(<vector crypto>)
which Eric pointed out was a poor design some months ago.

The rest of this is adding some requirements to the bindings that
prevent combinations of extensions disallowed by the ISA.

There's a bunch of over-long lines in here, but I thought that the
over-long lines were clearer than breaking them up.

Cheers,
Conor.

v3:
- rebase on v6.14-rc1
- split vector crypto validation patch into vector validation and vector
  crypto validation
- fix zve64x requiring extension list to match Eric's PR

v2:
- Fix an inverted clause Clément pointed out
- Add Zvbb validation, that I had missed accidentally
- Drop the todo about checking the number of validation rounds,
  I tried in w/ qemu's max cpu and things looked right

CC: Eric Biggers <ebiggers@kernel.org>
CC: Conor Dooley <conor@kernel.org>
CC: Rob Herring <robh@kernel.org>
CC: Krzysztof Kozlowski <krzk+dt@kernel.org>
CC: Paul Walmsley <paul.walmsley@sifive.com>
CC: Palmer Dabbelt <palmer@dabbelt.com>
CC: "Clément Léger" <cleger@rivosinc.com>
CC: Andy Chiu <andybnac@gmail.com>
CC: linux-riscv@lists.infradead.org
CC: devicetree@vger.kernel.org
CC: linux-kernel@vger.kernel.org

Conor Dooley (6):
  RISC-V: add vector extension validation checks
  RISC-V: add vector crypto extension validation checks
  RISC-V: add f & d extension validation checks
  dt-bindings: riscv: d requires f
  dt-bindings: riscv: add vector sub-extension dependencies
  dt-bindings: riscv: document vector crypto requirements

 .../devicetree/bindings/riscv/extensions.yaml |  85 +++++++++++
 arch/riscv/include/asm/cpufeature.h           |   3 +
 arch/riscv/kernel/cpufeature.c                | 133 +++++++++++++-----
 3 files changed, 183 insertions(+), 38 deletions(-)

-- 
2.45.2

[PATCH v3 1/6] RISC-V: add vector extension validation checks

[Conor Dooley]

From: Conor Dooley <conor.dooley@microchip.com>

Using Clement's new validation callbacks, support checking that
dependencies have been satisfied for the vector extensions. From the
kernel's perfective, it's not required to differentiate between the
conditions for all the various vector subsets - it's the firmware's job
to not report impossible combinations. Instead, the kernel only has to
check that the correct config options are enabled and to enforce its
requirement of the d extension being present for FPU support.

Since vector will now be disabled proactively, there's no need to clear
the bit in elf_hwcap in riscv_fill_hwcap() any longer.

Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
---
 arch/riscv/include/asm/cpufeature.h |  3 ++
 arch/riscv/kernel/cpufeature.c      | 57 +++++++++++++++++++----------
 2 files changed, 40 insertions(+), 20 deletions(-)

diff --git a/arch/riscv/include/asm/cpufeature.h b/arch/riscv/include/asm/cpufeature.h
index 569140d6e639..5d9427ccbc7a 100644
--- a/arch/riscv/include/asm/cpufeature.h
+++ b/arch/riscv/include/asm/cpufeature.h
@@ -56,6 +56,9 @@ void __init riscv_user_isa_enable(void);
 #define __RISCV_ISA_EXT_BUNDLE(_name, _bundled_exts) \
 	_RISCV_ISA_EXT_DATA(_name, RISCV_ISA_EXT_INVALID, _bundled_exts, \
 			    ARRAY_SIZE(_bundled_exts), NULL)
+#define __RISCV_ISA_EXT_BUNDLE_VALIDATE(_name, _bundled_exts, _validate) \
+	_RISCV_ISA_EXT_DATA(_name, RISCV_ISA_EXT_INVALID, _bundled_exts, \
+			    ARRAY_SIZE(_bundled_exts), _validate)
 
 /* Used to declare extensions that are a superset of other extensions (Zvbb for instance) */
 #define __RISCV_ISA_EXT_SUPERSET(_name, _id, _sub_exts) \
diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
index c6ba750536c3..40a24b08d905 100644
--- a/arch/riscv/kernel/cpufeature.c
+++ b/arch/riscv/kernel/cpufeature.c
@@ -109,6 +109,35 @@ static int riscv_ext_zicboz_validate(const struct riscv_isa_ext_data *data,
 	return 0;
 }
 
+static int riscv_ext_vector_x_validate(const struct riscv_isa_ext_data *data,
+				       const unsigned long *isa_bitmap)
+{
+	if (!IS_ENABLED(CONFIG_RISCV_ISA_V))
+		return -EINVAL;
+
+	return 0;
+}
+
+static int riscv_ext_vector_float_validate(const struct riscv_isa_ext_data *data,
+					   const unsigned long *isa_bitmap)
+{
+	if (!IS_ENABLED(CONFIG_RISCV_ISA_V))
+		return -EINVAL;
+
+	if (!IS_ENABLED(CONFIG_FPU))
+		return -EINVAL;
+
+	/*
+	 * The kernel doesn't support systems that don't implement both of
+	 * F and D, so if any of the vector extensions that do floating point
+	 * are to be usable, both floating point extensions need to be usable.
+	 */
+	if (!__riscv_isa_extension_available(isa_bitmap, RISCV_ISA_EXT_d))
+		return -EINVAL;
+
+	return 0;
+}
+
 static int riscv_ext_zca_depends(const struct riscv_isa_ext_data *data,
 				 const unsigned long *isa_bitmap)
 {
@@ -326,12 +355,10 @@ const struct riscv_isa_ext_data riscv_isa_ext[] = {
 	__RISCV_ISA_EXT_DATA(d, RISCV_ISA_EXT_d),
 	__RISCV_ISA_EXT_DATA(q, RISCV_ISA_EXT_q),
 	__RISCV_ISA_EXT_SUPERSET(c, RISCV_ISA_EXT_c, riscv_c_exts),
-	__RISCV_ISA_EXT_SUPERSET(v, RISCV_ISA_EXT_v, riscv_v_exts),
+	__RISCV_ISA_EXT_SUPERSET_VALIDATE(v, RISCV_ISA_EXT_v, riscv_v_exts, riscv_ext_vector_float_validate),
 	__RISCV_ISA_EXT_DATA(h, RISCV_ISA_EXT_h),
-	__RISCV_ISA_EXT_SUPERSET_VALIDATE(zicbom, RISCV_ISA_EXT_ZICBOM, riscv_xlinuxenvcfg_exts,
-					  riscv_ext_zicbom_validate),
-	__RISCV_ISA_EXT_SUPERSET_VALIDATE(zicboz, RISCV_ISA_EXT_ZICBOZ, riscv_xlinuxenvcfg_exts,
-					  riscv_ext_zicboz_validate),
+	__RISCV_ISA_EXT_SUPERSET_VALIDATE(zicbom, RISCV_ISA_EXT_ZICBOM, riscv_xlinuxenvcfg_exts, riscv_ext_zicbom_validate),
+	__RISCV_ISA_EXT_SUPERSET_VALIDATE(zicboz, RISCV_ISA_EXT_ZICBOZ, riscv_xlinuxenvcfg_exts, riscv_ext_zicboz_validate),
 	__RISCV_ISA_EXT_DATA(ziccrse, RISCV_ISA_EXT_ZICCRSE),
 	__RISCV_ISA_EXT_DATA(zicntr, RISCV_ISA_EXT_ZICNTR),
 	__RISCV_ISA_EXT_DATA(zicond, RISCV_ISA_EXT_ZICOND),
@@ -372,11 +399,11 @@ const struct riscv_isa_ext_data riscv_isa_ext[] = {
 	__RISCV_ISA_EXT_DATA(ztso, RISCV_ISA_EXT_ZTSO),
 	__RISCV_ISA_EXT_SUPERSET(zvbb, RISCV_ISA_EXT_ZVBB, riscv_zvbb_exts),
 	__RISCV_ISA_EXT_DATA(zvbc, RISCV_ISA_EXT_ZVBC),
-	__RISCV_ISA_EXT_SUPERSET(zve32f, RISCV_ISA_EXT_ZVE32F, riscv_zve32f_exts),
-	__RISCV_ISA_EXT_DATA(zve32x, RISCV_ISA_EXT_ZVE32X),
-	__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_SUPERSET_VALIDATE(zve32f, RISCV_ISA_EXT_ZVE32F, riscv_zve32f_exts, riscv_ext_vector_float_validate),
+	__RISCV_ISA_EXT_DATA_VALIDATE(zve32x, RISCV_ISA_EXT_ZVE32X, riscv_ext_vector_x_validate),
+	__RISCV_ISA_EXT_SUPERSET_VALIDATE(zve64d, RISCV_ISA_EXT_ZVE64D, riscv_zve64d_exts, riscv_ext_vector_float_validate),
+	__RISCV_ISA_EXT_SUPERSET_VALIDATE(zve64f, RISCV_ISA_EXT_ZVE64F, riscv_zve64f_exts, riscv_ext_vector_float_validate),
+	__RISCV_ISA_EXT_SUPERSET_VALIDATE(zve64x, RISCV_ISA_EXT_ZVE64X, riscv_zve64x_exts, riscv_ext_vector_x_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),
@@ -960,16 +987,6 @@ void __init riscv_fill_hwcap(void)
 		riscv_v_setup_vsize();
 	}
 
-	if (elf_hwcap & COMPAT_HWCAP_ISA_V) {
-		/*
-		 * ISA string in device tree might have 'v' flag, but
-		 * CONFIG_RISCV_ISA_V is disabled in kernel.
-		 * Clear V flag in elf_hwcap if CONFIG_RISCV_ISA_V is disabled.
-		 */
-		if (!IS_ENABLED(CONFIG_RISCV_ISA_V))
-			elf_hwcap &= ~COMPAT_HWCAP_ISA_V;
-	}
-
 	memset(print_str, 0, sizeof(print_str));
 	for (i = 0, j = 0; i < NUM_ALPHA_EXTS; i++)
 		if (riscv_isa[0] & BIT_MASK(i))
-- 
2.45.2

[PATCH v3 2/6] RISC-V: add vector crypto extension validation checks

[Conor Dooley]

From: Conor Dooley <conor.dooley@microchip.com>

Using Clement's new validation callbacks, support checking that
dependencies have been satisfied for the vector crpyto extensions.
Currently riscv_isa_extension_available(<vector crypto>) will return
true on systems that support the extensions but vector itself has been
disabled by the kernel, adding validation callbacks will prevent such a
scenario from occuring and make the behaviour of the extension detection
functions more consistent with user expectations - it's not expected to
have to check for vector AND the specific crypto extension.

The 1.0.0 Vector crypto spec states:
	The Zvknhb and Zvbc Vector Crypto Extensions --and accordingly
	the composite extensions Zvkn and Zvks-- require a Zve64x base,
	or application ("V") base Vector Extension. All of the other
	Vector Crypto Extensions can be built on any embedded (Zve*) or
	application ("V") base Vector Extension.
and this could be used as the basis for checking that the correct base
for individual crypto extensions, but that's not really the kernel's job
in my opinion and it is sufficient to leave that sort of precision to
the dt-bindings. The kernel only needs to make sure that vector, in some
form, is available.

Since vector will now be disabled proactively, there's no need to clear
the bit in elf_hwcap in riscv_fill_hwcap() any longer.

Link: https://github.com/riscv/riscv-crypto/releases/tag/v1.0.0
Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
---
 arch/riscv/kernel/cpufeature.c | 49 +++++++++++++++++++++++-----------
 1 file changed, 33 insertions(+), 16 deletions(-)

diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
index 40a24b08d905..1c148ecea612 100644
--- a/arch/riscv/kernel/cpufeature.c
+++ b/arch/riscv/kernel/cpufeature.c
@@ -138,6 +138,23 @@ static int riscv_ext_vector_float_validate(const struct riscv_isa_ext_data *data
 	return 0;
 }
 
+static int riscv_ext_vector_crypto_validate(const struct riscv_isa_ext_data *data,
+					    const unsigned long *isa_bitmap)
+{
+	if (!IS_ENABLED(CONFIG_RISCV_ISA_V))
+		return -EINVAL;
+
+	/*
+	 * It isn't the kernel's job to check that the binding is correct, so
+	 * it should be enough to check that any of the vector extensions are
+	 * enabled, which in-turn means that vector is usable in this kernel
+	 */
+	if (!__riscv_isa_extension_available(isa_bitmap, RISCV_ISA_EXT_ZVE32X))
+		return -EINVAL;
+
+	return 0;
+}
+
 static int riscv_ext_zca_depends(const struct riscv_isa_ext_data *data,
 				 const unsigned long *isa_bitmap)
 {
@@ -397,8 +414,8 @@ const struct riscv_isa_ext_data riscv_isa_ext[] = {
 	__RISCV_ISA_EXT_DATA(zksed, RISCV_ISA_EXT_ZKSED),
 	__RISCV_ISA_EXT_DATA(zksh, RISCV_ISA_EXT_ZKSH),
 	__RISCV_ISA_EXT_DATA(ztso, RISCV_ISA_EXT_ZTSO),
-	__RISCV_ISA_EXT_SUPERSET(zvbb, RISCV_ISA_EXT_ZVBB, riscv_zvbb_exts),
-	__RISCV_ISA_EXT_DATA(zvbc, RISCV_ISA_EXT_ZVBC),
+	__RISCV_ISA_EXT_SUPERSET_VALIDATE(zvbb, RISCV_ISA_EXT_ZVBB, riscv_zvbb_exts, riscv_ext_vector_x_validate),
+	__RISCV_ISA_EXT_DATA_VALIDATE(zvbc, RISCV_ISA_EXT_ZVBC, riscv_ext_vector_crypto_validate),
 	__RISCV_ISA_EXT_SUPERSET_VALIDATE(zve32f, RISCV_ISA_EXT_ZVE32F, riscv_zve32f_exts, riscv_ext_vector_float_validate),
 	__RISCV_ISA_EXT_DATA_VALIDATE(zve32x, RISCV_ISA_EXT_ZVE32X, riscv_ext_vector_x_validate),
 	__RISCV_ISA_EXT_SUPERSET_VALIDATE(zve64d, RISCV_ISA_EXT_ZVE64D, riscv_zve64d_exts, riscv_ext_vector_float_validate),
@@ -406,20 +423,20 @@ const struct riscv_isa_ext_data riscv_isa_ext[] = {
 	__RISCV_ISA_EXT_SUPERSET_VALIDATE(zve64x, RISCV_ISA_EXT_ZVE64X, riscv_zve64x_exts, riscv_ext_vector_x_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),
-	__RISCV_ISA_EXT_DATA(zvkg, RISCV_ISA_EXT_ZVKG),
-	__RISCV_ISA_EXT_BUNDLE(zvkn, riscv_zvkn_bundled_exts),
-	__RISCV_ISA_EXT_BUNDLE(zvknc, riscv_zvknc_bundled_exts),
-	__RISCV_ISA_EXT_DATA(zvkned, RISCV_ISA_EXT_ZVKNED),
-	__RISCV_ISA_EXT_BUNDLE(zvkng, riscv_zvkng_bundled_exts),
-	__RISCV_ISA_EXT_DATA(zvknha, RISCV_ISA_EXT_ZVKNHA),
-	__RISCV_ISA_EXT_DATA(zvknhb, RISCV_ISA_EXT_ZVKNHB),
-	__RISCV_ISA_EXT_BUNDLE(zvks, riscv_zvks_bundled_exts),
-	__RISCV_ISA_EXT_BUNDLE(zvksc, riscv_zvksc_bundled_exts),
-	__RISCV_ISA_EXT_DATA(zvksed, RISCV_ISA_EXT_ZVKSED),
-	__RISCV_ISA_EXT_DATA(zvksh, RISCV_ISA_EXT_ZVKSH),
-	__RISCV_ISA_EXT_BUNDLE(zvksg, riscv_zvksg_bundled_exts),
-	__RISCV_ISA_EXT_DATA(zvkt, RISCV_ISA_EXT_ZVKT),
+	__RISCV_ISA_EXT_DATA_VALIDATE(zvkb, RISCV_ISA_EXT_ZVKB, riscv_ext_vector_crypto_validate),
+	__RISCV_ISA_EXT_DATA_VALIDATE(zvkg, RISCV_ISA_EXT_ZVKG, riscv_ext_vector_crypto_validate),
+	__RISCV_ISA_EXT_BUNDLE_VALIDATE(zvkn, riscv_zvkn_bundled_exts, riscv_ext_vector_crypto_validate),
+	__RISCV_ISA_EXT_BUNDLE_VALIDATE(zvknc, riscv_zvknc_bundled_exts, riscv_ext_vector_crypto_validate),
+	__RISCV_ISA_EXT_DATA_VALIDATE(zvkned, RISCV_ISA_EXT_ZVKNED, riscv_ext_vector_crypto_validate),
+	__RISCV_ISA_EXT_BUNDLE_VALIDATE(zvkng, riscv_zvkng_bundled_exts, riscv_ext_vector_crypto_validate),
+	__RISCV_ISA_EXT_DATA_VALIDATE(zvknha, RISCV_ISA_EXT_ZVKNHA, riscv_ext_vector_crypto_validate),
+	__RISCV_ISA_EXT_DATA_VALIDATE(zvknhb, RISCV_ISA_EXT_ZVKNHB, riscv_ext_vector_crypto_validate),
+	__RISCV_ISA_EXT_BUNDLE_VALIDATE(zvks, riscv_zvks_bundled_exts, riscv_ext_vector_crypto_validate),
+	__RISCV_ISA_EXT_BUNDLE_VALIDATE(zvksc, riscv_zvksc_bundled_exts, riscv_ext_vector_crypto_validate),
+	__RISCV_ISA_EXT_DATA_VALIDATE(zvksed, RISCV_ISA_EXT_ZVKSED, riscv_ext_vector_crypto_validate),
+	__RISCV_ISA_EXT_DATA_VALIDATE(zvksh, RISCV_ISA_EXT_ZVKSH, riscv_ext_vector_crypto_validate),
+	__RISCV_ISA_EXT_BUNDLE_VALIDATE(zvksg, riscv_zvksg_bundled_exts, riscv_ext_vector_crypto_validate),
+	__RISCV_ISA_EXT_DATA_VALIDATE(zvkt, RISCV_ISA_EXT_ZVKT, riscv_ext_vector_crypto_validate),
 	__RISCV_ISA_EXT_DATA(smaia, RISCV_ISA_EXT_SMAIA),
 	__RISCV_ISA_EXT_DATA(smmpm, RISCV_ISA_EXT_SMMPM),
 	__RISCV_ISA_EXT_SUPERSET(smnpm, RISCV_ISA_EXT_SMNPM, riscv_xlinuxenvcfg_exts),
-- 
2.45.2

[PATCH v3 3/6] RISC-V: add f & d extension validation checks

[Conor Dooley]

From: Conor Dooley <conor.dooley@microchip.com>

Using Clement's new validation callbacks, support checking that
dependencies have been satisfied for the floating point extensions.

The check for "d" might be slightly confusingly shorter than that of "f",
despite "d" depending on "f". This is because the requirement that a
hart supporting double precision must also support single precision,
should be validated by dt-bindings etc, not the kernel but lack of
support for single precision only is a limitation of the kernel.

Since vector will now be disabled proactively, there's no need to clear
the bit in elf_hwcap in riscv_fill_hwcap() any longer.

Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
---
 arch/riscv/kernel/cpufeature.c | 27 +++++++++++++++++++++++++--
 1 file changed, 25 insertions(+), 2 deletions(-)

diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
index 1c148ecea612..ad4fbaa4ff0d 100644
--- a/arch/riscv/kernel/cpufeature.c
+++ b/arch/riscv/kernel/cpufeature.c
@@ -109,6 +109,29 @@ static int riscv_ext_zicboz_validate(const struct riscv_isa_ext_data *data,
 	return 0;
 }
 
+static int riscv_ext_f_validate(const struct riscv_isa_ext_data *data,
+				const unsigned long *isa_bitmap)
+{
+	if (!__riscv_isa_extension_available(isa_bitmap, RISCV_ISA_EXT_d)) {
+		pr_warn_once("This kernel does not support systems with F but not D\n");
+		return -EINVAL;
+	}
+
+	if (!IS_ENABLED(CONFIG_FPU))
+		return -EINVAL;
+
+	return 0;
+}
+
+static int riscv_ext_d_validate(const struct riscv_isa_ext_data *data,
+				const unsigned long *isa_bitmap)
+{
+	if (!IS_ENABLED(CONFIG_FPU))
+		return -EINVAL;
+
+	return 0;
+}
+
 static int riscv_ext_vector_x_validate(const struct riscv_isa_ext_data *data,
 				       const unsigned long *isa_bitmap)
 {
@@ -368,8 +391,8 @@ const struct riscv_isa_ext_data riscv_isa_ext[] = {
 	__RISCV_ISA_EXT_DATA(i, RISCV_ISA_EXT_i),
 	__RISCV_ISA_EXT_DATA(m, RISCV_ISA_EXT_m),
 	__RISCV_ISA_EXT_DATA(a, RISCV_ISA_EXT_a),
-	__RISCV_ISA_EXT_DATA(f, RISCV_ISA_EXT_f),
-	__RISCV_ISA_EXT_DATA(d, RISCV_ISA_EXT_d),
+	__RISCV_ISA_EXT_DATA_VALIDATE(f, RISCV_ISA_EXT_f, riscv_ext_f_validate),
+	__RISCV_ISA_EXT_DATA_VALIDATE(d, RISCV_ISA_EXT_d, riscv_ext_d_validate),
 	__RISCV_ISA_EXT_DATA(q, RISCV_ISA_EXT_q),
 	__RISCV_ISA_EXT_SUPERSET(c, RISCV_ISA_EXT_c, riscv_c_exts),
 	__RISCV_ISA_EXT_SUPERSET_VALIDATE(v, RISCV_ISA_EXT_v, riscv_v_exts, riscv_ext_vector_float_validate),
-- 
2.45.2

[PATCH v3 4/6] dt-bindings: riscv: d requires f

[Conor Dooley]

From: Conor Dooley <conor.dooley@microchip.com>

Per the specifications, the d extension for double-precision floating
point operations depends on the f extension for single-precision floating
point. Add that requirement to the bindings. This differs from the
Linux implementation, where single-precious only is not supported.

Reviewed-by: Clément Léger <cleger@rivosinc.com>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
---
 Documentation/devicetree/bindings/riscv/extensions.yaml | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/Documentation/devicetree/bindings/riscv/extensions.yaml b/Documentation/devicetree/bindings/riscv/extensions.yaml
index a63b994e0763..ebb252275ddd 100644
--- a/Documentation/devicetree/bindings/riscv/extensions.yaml
+++ b/Documentation/devicetree/bindings/riscv/extensions.yaml
@@ -639,6 +639,12 @@ properties:
             https://github.com/T-head-Semi/thead-extension-spec/blob/95358cb2cca9489361c61d335e03d3134b14133f/xtheadvector.adoc.
 
     allOf:
+      - if:
+          contains:
+            const: d
+        then:
+          contains:
+            const: f
       # Zcb depends on Zca
       - if:
           contains:
-- 
2.45.2

[PATCH v3 5/6] dt-bindings: riscv: add vector sub-extension dependencies

[Conor Dooley]

From: Conor Dooley <conor.dooley@microchip.com>

Section 33.18.2. Zve*: Vector Extensions for Embedded Processors
in [1] says:
| The Zve32f and Zve64x extensions depend on the Zve32x extension. The Zve64f extension depends
| on the Zve32f and Zve64x extensions. The Zve64d extension depends on the Zve64f extension

| The Zve32x extension depends on the Zicsr extension. The Zve32f and Zve64f extensions depend
| upon the F extension

| The Zve64d extension depends upon the D extension

Apply these rules to the bindings to help prevent invalid combinations.

Link: https://github.com/riscv/riscv-isa-manual/releases/tag/riscv-isa-release-698e64a-2024-09-09 [1]
Reviewed-by: Clément Léger <cleger@rivosinc.com>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
---
 .../devicetree/bindings/riscv/extensions.yaml | 46 +++++++++++++++++++
 1 file changed, 46 insertions(+)

diff --git a/Documentation/devicetree/bindings/riscv/extensions.yaml b/Documentation/devicetree/bindings/riscv/extensions.yaml
index ebb252275ddd..02065664f819 100644
--- a/Documentation/devicetree/bindings/riscv/extensions.yaml
+++ b/Documentation/devicetree/bindings/riscv/extensions.yaml
@@ -680,6 +680,52 @@ properties:
           contains:
             const: zca
 
+      - if:
+          contains:
+            const: zve32x
+        then:
+          contains:
+            const: zicsr
+
+      - if:
+          contains:
+            const: zve32f
+        then:
+          allOf:
+            - contains:
+                const: f
+            - contains:
+                const: zve32x
+
+      - if:
+          contains:
+            const: zve64x
+        then:
+          contains:
+            const: zve32x
+
+      - if:
+          contains:
+            const: zve64f
+        then:
+          allOf:
+            - contains:
+                const: f
+            - contains:
+                const: zve32f
+            - contains:
+                const: zve64x
+
+      - if:
+          contains:
+            const: zve64d
+        then:
+          allOf:
+            - contains:
+                const: d
+            - contains:
+                const: zve64f
+
 allOf:
   # Zcf extension does not exist on rv64
   - if:
-- 
2.45.2

[PATCH v3 6/6] dt-bindings: riscv: document vector crypto requirements

[Conor Dooley]

From: Conor Dooley <conor.dooley@microchip.com>

Section 35.2. Extensions Overview of [1] says:
| The Zvknhb and Zvbc Vector Crypto Extensions --and accordingly the composite extensions Zvkn and
| Zvks-- (sic) require a Zve64x base, or application ("V") base Vector Extension.
| All of the other Vector Crypto Extensions can be built on any embedded (Zve*) or application ("V") base
| Vector Extension

Eric Biggars pointed out that the spec is actually incorrect, and that
the list of instructions requiring a Zve64x base is actually: Zvkn,
Zvknc, Zvkng and Zvksc. Implement the rules according to his PR [2].

Link: https://github.com/riscv/riscv-isa-manual/releases/tag/riscv-isa-release-698e64a-2024-09-09 [1]
Link: https://github.com/riscv/riscv-isa-manual/pull/1697 [2]
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
---
 .../devicetree/bindings/riscv/extensions.yaml | 33 +++++++++++++++++++
 1 file changed, 33 insertions(+)

diff --git a/Documentation/devicetree/bindings/riscv/extensions.yaml b/Documentation/devicetree/bindings/riscv/extensions.yaml
index 02065664f819..9aeb9d4731ca 100644
--- a/Documentation/devicetree/bindings/riscv/extensions.yaml
+++ b/Documentation/devicetree/bindings/riscv/extensions.yaml
@@ -726,6 +726,39 @@ properties:
             - contains:
                 const: zve64f
 
+      - if:
+          contains:
+            anyOf:
+              - const: zvbc
+              - const: zvkn
+              - const: zvknc
+              - const: zvkng
+              - const: zvknhb
+              - const: zvksc
+        then:
+          contains:
+            anyOf:
+              - const: v
+              - const: zve64x
+
+      - if:
+          contains:
+            anyOf:
+              - const: zvbb
+              - const: zvkb
+              - const: zvkg
+              - const: zvkned
+              - const: zvknha
+              - const: zvksed
+              - const: zvksh
+              - const: zvks
+              - const: zvkt
+        then:
+          contains:
+            anyOf:
+              - const: v
+              - const: zve32x
+
 allOf:
   # Zcf extension does not exist on rv64
   - if:
-- 
2.45.2

Re: [PATCH v3 3/6] RISC-V: add f & d extension validation checks

[Clément Léger]

On 05/02/2025 17:05, Conor Dooley wrote:
> From: Conor Dooley <conor.dooley@microchip.com>
> 
> Using Clement's new validation callbacks, support checking that
> dependencies have been satisfied for the floating point extensions.
> 
> The check for "d" might be slightly confusingly shorter than that of "f",
> despite "d" depending on "f". This is because the requirement that a
> hart supporting double precision must also support single precision,
> should be validated by dt-bindings etc, not the kernel but lack of
> support for single precision only is a limitation of the kernel.
> 
> Since vector will now be disabled proactively, there's no need to clear
> the bit in elf_hwcap in riscv_fill_hwcap() any longer.
> 
> Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
> ---
>  arch/riscv/kernel/cpufeature.c | 27 +++++++++++++++++++++++++--
>  1 file changed, 25 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
> index 1c148ecea612..ad4fbaa4ff0d 100644
> --- a/arch/riscv/kernel/cpufeature.c
> +++ b/arch/riscv/kernel/cpufeature.c
> @@ -109,6 +109,29 @@ static int riscv_ext_zicboz_validate(const struct riscv_isa_ext_data *data,
>  	return 0;
>  }
>  
> +static int riscv_ext_f_validate(const struct riscv_isa_ext_data *data,
> +				const unsigned long *isa_bitmap)
> +{
> +	if (!__riscv_isa_extension_available(isa_bitmap, RISCV_ISA_EXT_d)) {
> +		pr_warn_once("This kernel does not support systems with F but not D\n");
> +		return -EINVAL;
> +	}
> +
> +	if (!IS_ENABLED(CONFIG_FPU))
> +		return -EINVAL;
> +
> +	return 0;
> +}
> +
> +static int riscv_ext_d_validate(const struct riscv_isa_ext_data *data,
> +				const unsigned long *isa_bitmap)
> +{
> +	if (!IS_ENABLED(CONFIG_FPU))
> +		return -EINVAL;
> +
> +	return 0;
> +}
> +
>  static int riscv_ext_vector_x_validate(const struct riscv_isa_ext_data *data,
>  				       const unsigned long *isa_bitmap)
>  {
> @@ -368,8 +391,8 @@ const struct riscv_isa_ext_data riscv_isa_ext[] = {
>  	__RISCV_ISA_EXT_DATA(i, RISCV_ISA_EXT_i),
>  	__RISCV_ISA_EXT_DATA(m, RISCV_ISA_EXT_m),
>  	__RISCV_ISA_EXT_DATA(a, RISCV_ISA_EXT_a),
> -	__RISCV_ISA_EXT_DATA(f, RISCV_ISA_EXT_f),
> -	__RISCV_ISA_EXT_DATA(d, RISCV_ISA_EXT_d),
> +	__RISCV_ISA_EXT_DATA_VALIDATE(f, RISCV_ISA_EXT_f, riscv_ext_f_validate),
> +	__RISCV_ISA_EXT_DATA_VALIDATE(d, RISCV_ISA_EXT_d, riscv_ext_d_validate),
>  	__RISCV_ISA_EXT_DATA(q, RISCV_ISA_EXT_q),
>  	__RISCV_ISA_EXT_SUPERSET(c, RISCV_ISA_EXT_c, riscv_c_exts),
>  	__RISCV_ISA_EXT_SUPERSET_VALIDATE(v, RISCV_ISA_EXT_v, riscv_v_exts, riscv_ext_vector_float_validate),

Hi Conor,

Tested-by: Clément Léger <cleger@rivosinc.com>
Reviewed-by: Clément Léger <cleger@rivosinc.com>

Thanks,

Clément

Re: [PATCH v3 1/6] RISC-V: add vector extension validation checks

[Clément Léger]

On 05/02/2025 17:05, Conor Dooley wrote:
> From: Conor Dooley <conor.dooley@microchip.com>
> 
> Using Clement's new validation callbacks, support checking that
> dependencies have been satisfied for the vector extensions. From the
> kernel's perfective, it's not required to differentiate between the
> conditions for all the various vector subsets - it's the firmware's job
> to not report impossible combinations. Instead, the kernel only has to
> check that the correct config options are enabled and to enforce its
> requirement of the d extension being present for FPU support.
> 
> Since vector will now be disabled proactively, there's no need to clear
> the bit in elf_hwcap in riscv_fill_hwcap() any longer.
> 
> Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
> ---
>  arch/riscv/include/asm/cpufeature.h |  3 ++
>  arch/riscv/kernel/cpufeature.c      | 57 +++++++++++++++++++----------
>  2 files changed, 40 insertions(+), 20 deletions(-)
> 
> diff --git a/arch/riscv/include/asm/cpufeature.h b/arch/riscv/include/asm/cpufeature.h
> index 569140d6e639..5d9427ccbc7a 100644
> --- a/arch/riscv/include/asm/cpufeature.h
> +++ b/arch/riscv/include/asm/cpufeature.h
> @@ -56,6 +56,9 @@ void __init riscv_user_isa_enable(void);
>  #define __RISCV_ISA_EXT_BUNDLE(_name, _bundled_exts) \
>  	_RISCV_ISA_EXT_DATA(_name, RISCV_ISA_EXT_INVALID, _bundled_exts, \
>  			    ARRAY_SIZE(_bundled_exts), NULL)
> +#define __RISCV_ISA_EXT_BUNDLE_VALIDATE(_name, _bundled_exts, _validate) \
> +	_RISCV_ISA_EXT_DATA(_name, RISCV_ISA_EXT_INVALID, _bundled_exts, \
> +			    ARRAY_SIZE(_bundled_exts), _validate)
>  
>  /* Used to declare extensions that are a superset of other extensions (Zvbb for instance) */
>  #define __RISCV_ISA_EXT_SUPERSET(_name, _id, _sub_exts) \
> diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
> index c6ba750536c3..40a24b08d905 100644
> --- a/arch/riscv/kernel/cpufeature.c
> +++ b/arch/riscv/kernel/cpufeature.c
> @@ -109,6 +109,35 @@ static int riscv_ext_zicboz_validate(const struct riscv_isa_ext_data *data,
>  	return 0;
>  }
>  
> +static int riscv_ext_vector_x_validate(const struct riscv_isa_ext_data *data,
> +				       const unsigned long *isa_bitmap)
> +{
> +	if (!IS_ENABLED(CONFIG_RISCV_ISA_V))
> +		return -EINVAL;
> +
> +	return 0;
> +}
> +
> +static int riscv_ext_vector_float_validate(const struct riscv_isa_ext_data *data,
> +					   const unsigned long *isa_bitmap)
> +{
> +	if (!IS_ENABLED(CONFIG_RISCV_ISA_V))
> +		return -EINVAL;
> +
> +	if (!IS_ENABLED(CONFIG_FPU))
> +		return -EINVAL;
> +
> +	/*
> +	 * The kernel doesn't support systems that don't implement both of
> +	 * F and D, so if any of the vector extensions that do floating point
> +	 * are to be usable, both floating point extensions need to be usable.
> +	 */
> +	if (!__riscv_isa_extension_available(isa_bitmap, RISCV_ISA_EXT_d))
> +		return -EINVAL;
> +
> +	return 0;
> +}
> +
>  static int riscv_ext_zca_depends(const struct riscv_isa_ext_data *data,
>  				 const unsigned long *isa_bitmap)
>  {
> @@ -326,12 +355,10 @@ const struct riscv_isa_ext_data riscv_isa_ext[] = {
>  	__RISCV_ISA_EXT_DATA(d, RISCV_ISA_EXT_d),
>  	__RISCV_ISA_EXT_DATA(q, RISCV_ISA_EXT_q),
>  	__RISCV_ISA_EXT_SUPERSET(c, RISCV_ISA_EXT_c, riscv_c_exts),
> -	__RISCV_ISA_EXT_SUPERSET(v, RISCV_ISA_EXT_v, riscv_v_exts),
> +	__RISCV_ISA_EXT_SUPERSET_VALIDATE(v, RISCV_ISA_EXT_v, riscv_v_exts, riscv_ext_vector_float_validate),
>  	__RISCV_ISA_EXT_DATA(h, RISCV_ISA_EXT_h),
> -	__RISCV_ISA_EXT_SUPERSET_VALIDATE(zicbom, RISCV_ISA_EXT_ZICBOM, riscv_xlinuxenvcfg_exts,
> -					  riscv_ext_zicbom_validate),
> -	__RISCV_ISA_EXT_SUPERSET_VALIDATE(zicboz, RISCV_ISA_EXT_ZICBOZ, riscv_xlinuxenvcfg_exts,
> -					  riscv_ext_zicboz_validate),
> +	__RISCV_ISA_EXT_SUPERSET_VALIDATE(zicbom, RISCV_ISA_EXT_ZICBOM, riscv_xlinuxenvcfg_exts, riscv_ext_zicbom_validate),
> +	__RISCV_ISA_EXT_SUPERSET_VALIDATE(zicboz, RISCV_ISA_EXT_ZICBOZ, riscv_xlinuxenvcfg_exts, riscv_ext_zicboz_validate),

Hey Conor,

This chunk seems to just remove line wrapping for existing code, not
sure if this is intended.

Thanks,

Clément


>  	__RISCV_ISA_EXT_DATA(ziccrse, RISCV_ISA_EXT_ZICCRSE),
>  	__RISCV_ISA_EXT_DATA(zicntr, RISCV_ISA_EXT_ZICNTR),
>  	__RISCV_ISA_EXT_DATA(zicond, RISCV_ISA_EXT_ZICOND),
> @@ -372,11 +399,11 @@ const struct riscv_isa_ext_data riscv_isa_ext[] = {
>  	__RISCV_ISA_EXT_DATA(ztso, RISCV_ISA_EXT_ZTSO),
>  	__RISCV_ISA_EXT_SUPERSET(zvbb, RISCV_ISA_EXT_ZVBB, riscv_zvbb_exts),
>  	__RISCV_ISA_EXT_DATA(zvbc, RISCV_ISA_EXT_ZVBC),
> -	__RISCV_ISA_EXT_SUPERSET(zve32f, RISCV_ISA_EXT_ZVE32F, riscv_zve32f_exts),
> -	__RISCV_ISA_EXT_DATA(zve32x, RISCV_ISA_EXT_ZVE32X),
> -	__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_SUPERSET_VALIDATE(zve32f, RISCV_ISA_EXT_ZVE32F, riscv_zve32f_exts, riscv_ext_vector_float_validate),
> +	__RISCV_ISA_EXT_DATA_VALIDATE(zve32x, RISCV_ISA_EXT_ZVE32X, riscv_ext_vector_x_validate),
> +	__RISCV_ISA_EXT_SUPERSET_VALIDATE(zve64d, RISCV_ISA_EXT_ZVE64D, riscv_zve64d_exts, riscv_ext_vector_float_validate),
> +	__RISCV_ISA_EXT_SUPERSET_VALIDATE(zve64f, RISCV_ISA_EXT_ZVE64F, riscv_zve64f_exts, riscv_ext_vector_float_validate),
> +	__RISCV_ISA_EXT_SUPERSET_VALIDATE(zve64x, RISCV_ISA_EXT_ZVE64X, riscv_zve64x_exts, riscv_ext_vector_x_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),
> @@ -960,16 +987,6 @@ void __init riscv_fill_hwcap(void)
>  		riscv_v_setup_vsize();
>  	}
>  
> -	if (elf_hwcap & COMPAT_HWCAP_ISA_V) {
> -		/*
> -		 * ISA string in device tree might have 'v' flag, but
> -		 * CONFIG_RISCV_ISA_V is disabled in kernel.
> -		 * Clear V flag in elf_hwcap if CONFIG_RISCV_ISA_V is disabled.
> -		 */
> -		if (!IS_ENABLED(CONFIG_RISCV_ISA_V))
> -			elf_hwcap &= ~COMPAT_HWCAP_ISA_V;
> -	}
> -
>  	memset(print_str, 0, sizeof(print_str));
>  	for (i = 0, j = 0; i < NUM_ALPHA_EXTS; i++)
>  		if (riscv_isa[0] & BIT_MASK(i))

Re: [PATCH v3 2/6] RISC-V: add vector crypto extension validation checks

[Clément Léger]

On 05/02/2025 17:05, Conor Dooley wrote:
> From: Conor Dooley <conor.dooley@microchip.com>
> 
> Using Clement's new validation callbacks, support checking that
> dependencies have been satisfied for the vector crpyto extensions.
> Currently riscv_isa_extension_available(<vector crypto>) will return
> true on systems that support the extensions but vector itself has been
> disabled by the kernel, adding validation callbacks will prevent such a
> scenario from occuring and make the behaviour of the extension detection
> functions more consistent with user expectations - it's not expected to
> have to check for vector AND the specific crypto extension.
> 
> The 1.0.0 Vector crypto spec states:
> 	The Zvknhb and Zvbc Vector Crypto Extensions --and accordingly
> 	the composite extensions Zvkn and Zvks-- require a Zve64x base,
> 	or application ("V") base Vector Extension. All of the other
> 	Vector Crypto Extensions can be built on any embedded (Zve*) or
> 	application ("V") base Vector Extension.
> and this could be used as the basis for checking that the correct base
> for individual crypto extensions, but that's not really the kernel's job
> in my opinion and it is sufficient to leave that sort of precision to
> the dt-bindings. The kernel only needs to make sure that vector, in some
> form, is available.
> 
> Since vector will now be disabled proactively, there's no need to clear
> the bit in elf_hwcap in riscv_fill_hwcap() any longer.

Hey Conor,

To which part of the commit does this refer to ?

> 
> Link: https://github.com/riscv/riscv-crypto/releases/tag/v1.0.0
> Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
> ---
>  arch/riscv/kernel/cpufeature.c | 49 +++++++++++++++++++++++-----------
>  1 file changed, 33 insertions(+), 16 deletions(-)
> 
> diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
> index 40a24b08d905..1c148ecea612 100644
> --- a/arch/riscv/kernel/cpufeature.c
> +++ b/arch/riscv/kernel/cpufeature.c
> @@ -138,6 +138,23 @@ static int riscv_ext_vector_float_validate(const struct riscv_isa_ext_data *data
>  	return 0;
>  }
>  
> +static int riscv_ext_vector_crypto_validate(const struct riscv_isa_ext_data *data,
> +					    const unsigned long *isa_bitmap)
> +{
> +	if (!IS_ENABLED(CONFIG_RISCV_ISA_V))
> +		return -EINVAL;
> +
> +	/*
> +	 * It isn't the kernel's job to check that the binding is correct, so
> +	 * it should be enough to check that any of the vector extensions are
> +	 * enabled, which in-turn means that vector is usable in this kernel
> +	 */
> +	if (!__riscv_isa_extension_available(isa_bitmap, RISCV_ISA_EXT_ZVE32X))
> +		return -EINVAL;
> +
> +	return 0;
> +}
> +
>  static int riscv_ext_zca_depends(const struct riscv_isa_ext_data *data,
>  				 const unsigned long *isa_bitmap)
>  {
> @@ -397,8 +414,8 @@ const struct riscv_isa_ext_data riscv_isa_ext[] = {
>  	__RISCV_ISA_EXT_DATA(zksed, RISCV_ISA_EXT_ZKSED),
>  	__RISCV_ISA_EXT_DATA(zksh, RISCV_ISA_EXT_ZKSH),
>  	__RISCV_ISA_EXT_DATA(ztso, RISCV_ISA_EXT_ZTSO),
> -	__RISCV_ISA_EXT_SUPERSET(zvbb, RISCV_ISA_EXT_ZVBB, riscv_zvbb_exts),
> -	__RISCV_ISA_EXT_DATA(zvbc, RISCV_ISA_EXT_ZVBC),
> +	__RISCV_ISA_EXT_SUPERSET_VALIDATE(zvbb, RISCV_ISA_EXT_ZVBB, riscv_zvbb_exts, riscv_ext_vector_x_validate),
> +	__RISCV_ISA_EXT_DATA_VALIDATE(zvbc, RISCV_ISA_EXT_ZVBC, riscv_ext_vector_crypto_validate),
>  	__RISCV_ISA_EXT_SUPERSET_VALIDATE(zve32f, RISCV_ISA_EXT_ZVE32F, riscv_zve32f_exts, riscv_ext_vector_float_validate),
>  	__RISCV_ISA_EXT_DATA_VALIDATE(zve32x, RISCV_ISA_EXT_ZVE32X, riscv_ext_vector_x_validate),
>  	__RISCV_ISA_EXT_SUPERSET_VALIDATE(zve64d, RISCV_ISA_EXT_ZVE64D, riscv_zve64d_exts, riscv_ext_vector_float_validate),
> @@ -406,20 +423,20 @@ const struct riscv_isa_ext_data riscv_isa_ext[] = {
>  	__RISCV_ISA_EXT_SUPERSET_VALIDATE(zve64x, RISCV_ISA_EXT_ZVE64X, riscv_zve64x_exts, riscv_ext_vector_x_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),
> -	__RISCV_ISA_EXT_DATA(zvkg, RISCV_ISA_EXT_ZVKG),
> -	__RISCV_ISA_EXT_BUNDLE(zvkn, riscv_zvkn_bundled_exts),
> -	__RISCV_ISA_EXT_BUNDLE(zvknc, riscv_zvknc_bundled_exts),
> -	__RISCV_ISA_EXT_DATA(zvkned, RISCV_ISA_EXT_ZVKNED),
> -	__RISCV_ISA_EXT_BUNDLE(zvkng, riscv_zvkng_bundled_exts),
> -	__RISCV_ISA_EXT_DATA(zvknha, RISCV_ISA_EXT_ZVKNHA),
> -	__RISCV_ISA_EXT_DATA(zvknhb, RISCV_ISA_EXT_ZVKNHB),
> -	__RISCV_ISA_EXT_BUNDLE(zvks, riscv_zvks_bundled_exts),
> -	__RISCV_ISA_EXT_BUNDLE(zvksc, riscv_zvksc_bundled_exts),
> -	__RISCV_ISA_EXT_DATA(zvksed, RISCV_ISA_EXT_ZVKSED),
> -	__RISCV_ISA_EXT_DATA(zvksh, RISCV_ISA_EXT_ZVKSH),
> -	__RISCV_ISA_EXT_BUNDLE(zvksg, riscv_zvksg_bundled_exts),
> -	__RISCV_ISA_EXT_DATA(zvkt, RISCV_ISA_EXT_ZVKT),
> +	__RISCV_ISA_EXT_DATA_VALIDATE(zvkb, RISCV_ISA_EXT_ZVKB, riscv_ext_vector_crypto_validate),
> +	__RISCV_ISA_EXT_DATA_VALIDATE(zvkg, RISCV_ISA_EXT_ZVKG, riscv_ext_vector_crypto_validate),
> +	__RISCV_ISA_EXT_BUNDLE_VALIDATE(zvkn, riscv_zvkn_bundled_exts, riscv_ext_vector_crypto_validate),
> +	__RISCV_ISA_EXT_BUNDLE_VALIDATE(zvknc, riscv_zvknc_bundled_exts, riscv_ext_vector_crypto_validate),
> +	__RISCV_ISA_EXT_DATA_VALIDATE(zvkned, RISCV_ISA_EXT_ZVKNED, riscv_ext_vector_crypto_validate),
> +	__RISCV_ISA_EXT_BUNDLE_VALIDATE(zvkng, riscv_zvkng_bundled_exts, riscv_ext_vector_crypto_validate),
> +	__RISCV_ISA_EXT_DATA_VALIDATE(zvknha, RISCV_ISA_EXT_ZVKNHA, riscv_ext_vector_crypto_validate),
> +	__RISCV_ISA_EXT_DATA_VALIDATE(zvknhb, RISCV_ISA_EXT_ZVKNHB, riscv_ext_vector_crypto_validate),
> +	__RISCV_ISA_EXT_BUNDLE_VALIDATE(zvks, riscv_zvks_bundled_exts, riscv_ext_vector_crypto_validate),
> +	__RISCV_ISA_EXT_BUNDLE_VALIDATE(zvksc, riscv_zvksc_bundled_exts, riscv_ext_vector_crypto_validate),
> +	__RISCV_ISA_EXT_DATA_VALIDATE(zvksed, RISCV_ISA_EXT_ZVKSED, riscv_ext_vector_crypto_validate),
> +	__RISCV_ISA_EXT_DATA_VALIDATE(zvksh, RISCV_ISA_EXT_ZVKSH, riscv_ext_vector_crypto_validate),
> +	__RISCV_ISA_EXT_BUNDLE_VALIDATE(zvksg, riscv_zvksg_bundled_exts, riscv_ext_vector_crypto_validate),
> +	__RISCV_ISA_EXT_DATA_VALIDATE(zvkt, RISCV_ISA_EXT_ZVKT, riscv_ext_vector_crypto_validate),

I'm not sure if I already made that comment, so here we go again.
Shouldn't Zvbb use riscv_ext_vector_crypto_validate() as well ?  The
spec states that Zvbb is a superset of Zvkb and Zvkb uses the
riscv_ext_vector_crypto_validate() validation callback. I guess Zvbc
should also use it based on your spec excerpt in the commmit log.

Thanks,

Clément

>  	__RISCV_ISA_EXT_DATA(smaia, RISCV_ISA_EXT_SMAIA),
>  	__RISCV_ISA_EXT_DATA(smmpm, RISCV_ISA_EXT_SMMPM),
>  	__RISCV_ISA_EXT_SUPERSET(smnpm, RISCV_ISA_EXT_SMNPM, riscv_xlinuxenvcfg_exts),

Re: [PATCH v3 1/6] RISC-V: add vector extension validation checks

[Conor Dooley]

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On Thu, Feb 06, 2025 at 11:08:57AM +0100, Clément Léger wrote:
> On 05/02/2025 17:05, Conor Dooley wrote:
> > From: Conor Dooley <conor.dooley@microchip.com>
> >  static int riscv_ext_zca_depends(const struct riscv_isa_ext_data *data,
> >  				 const unsigned long *isa_bitmap)
> >  {
> > @@ -326,12 +355,10 @@ const struct riscv_isa_ext_data riscv_isa_ext[] = {
> >  	__RISCV_ISA_EXT_DATA(d, RISCV_ISA_EXT_d),
> >  	__RISCV_ISA_EXT_DATA(q, RISCV_ISA_EXT_q),
> >  	__RISCV_ISA_EXT_SUPERSET(c, RISCV_ISA_EXT_c, riscv_c_exts),
> > -	__RISCV_ISA_EXT_SUPERSET(v, RISCV_ISA_EXT_v, riscv_v_exts),
> > +	__RISCV_ISA_EXT_SUPERSET_VALIDATE(v, RISCV_ISA_EXT_v, riscv_v_exts, riscv_ext_vector_float_validate),
> >  	__RISCV_ISA_EXT_DATA(h, RISCV_ISA_EXT_h),
> > -	__RISCV_ISA_EXT_SUPERSET_VALIDATE(zicbom, RISCV_ISA_EXT_ZICBOM, riscv_xlinuxenvcfg_exts,
> > -					  riscv_ext_zicbom_validate),
> > -	__RISCV_ISA_EXT_SUPERSET_VALIDATE(zicboz, RISCV_ISA_EXT_ZICBOZ, riscv_xlinuxenvcfg_exts,
> > -					  riscv_ext_zicboz_validate),
> > +	__RISCV_ISA_EXT_SUPERSET_VALIDATE(zicbom, RISCV_ISA_EXT_ZICBOM, riscv_xlinuxenvcfg_exts, riscv_ext_zicbom_validate),
> > +	__RISCV_ISA_EXT_SUPERSET_VALIDATE(zicboz, RISCV_ISA_EXT_ZICBOZ, riscv_xlinuxenvcfg_exts, riscv_ext_zicboz_validate),
> 
> This chunk seems to just remove line wrapping for existing code, not
> sure if this is intended.

I probably removed the line wrapping from it in passing because I found
the array very difficult to follow once all the validate callbacks were
added to it with correct line wrapping applied. I did intend to not line
wrap what I was adding, I forgot I removed line wrapping for existing
stuff too.


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Re: [PATCH v3 2/6] RISC-V: add vector crypto extension validation checks

[Conor Dooley]

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On Thu, Feb 06, 2025 at 11:20:35AM +0100, Clément Léger wrote:
> On 05/02/2025 17:05, Conor Dooley wrote:
> > From: Conor Dooley <conor.dooley@microchip.com>
> > 
> > Using Clement's new validation callbacks, support checking that
> > dependencies have been satisfied for the vector crpyto extensions.
> > Currently riscv_isa_extension_available(<vector crypto>) will return
> > true on systems that support the extensions but vector itself has been
> > disabled by the kernel, adding validation callbacks will prevent such a
> > scenario from occuring and make the behaviour of the extension detection
> > functions more consistent with user expectations - it's not expected to
> > have to check for vector AND the specific crypto extension.
> > 
> > The 1.0.0 Vector crypto spec states:
> > 	The Zvknhb and Zvbc Vector Crypto Extensions --and accordingly
> > 	the composite extensions Zvkn and Zvks-- require a Zve64x base,
> > 	or application ("V") base Vector Extension. All of the other
> > 	Vector Crypto Extensions can be built on any embedded (Zve*) or
> > 	application ("V") base Vector Extension.
> > and this could be used as the basis for checking that the correct base
> > for individual crypto extensions, but that's not really the kernel's job
> > in my opinion and it is sufficient to leave that sort of precision to
> > the dt-bindings. The kernel only needs to make sure that vector, in some
> > form, is available.
> > 
> > Since vector will now be disabled proactively, there's no need to clear
> > the bit in elf_hwcap in riscv_fill_hwcap() any longer.
> 
> To which part of the commit does this refer to ?

Copy-paste mistake when splitting in two, whoops.

> > @@ -397,8 +414,8 @@ const struct riscv_isa_ext_data riscv_isa_ext[] = {
> >  	__RISCV_ISA_EXT_DATA(zksed, RISCV_ISA_EXT_ZKSED),
> >  	__RISCV_ISA_EXT_DATA(zksh, RISCV_ISA_EXT_ZKSH),
> >  	__RISCV_ISA_EXT_DATA(ztso, RISCV_ISA_EXT_ZTSO),
> > -	__RISCV_ISA_EXT_SUPERSET(zvbb, RISCV_ISA_EXT_ZVBB, riscv_zvbb_exts),
> > -	__RISCV_ISA_EXT_DATA(zvbc, RISCV_ISA_EXT_ZVBC),
> > +	__RISCV_ISA_EXT_SUPERSET_VALIDATE(zvbb, RISCV_ISA_EXT_ZVBB, riscv_zvbb_exts, riscv_ext_vector_x_validate),
> > +	__RISCV_ISA_EXT_DATA_VALIDATE(zvbc, RISCV_ISA_EXT_ZVBC, riscv_ext_vector_crypto_validate),

> 
> I'm not sure if I already made that comment, so here we go again.
> Shouldn't Zvbb use riscv_ext_vector_crypto_validate() as well ?  The
> spec states that Zvbb is a superset of Zvkb and Zvkb uses the
> riscv_ext_vector_crypto_validate() validation callback. I guess Zvbc
> should also use it based on your spec excerpt in the commmit log.

Zvbc does use it, no? I'll amend the Zvbb one, there should only be two
users of the "x" variant.

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Re: [PATCH v3 2/6] RISC-V: add vector crypto extension validation checks

[Clément Léger]

On 06/02/2025 12:24, Conor Dooley wrote:
> On Thu, Feb 06, 2025 at 11:20:35AM +0100, Clément Léger wrote:
>> On 05/02/2025 17:05, Conor Dooley wrote:
>>> From: Conor Dooley <conor.dooley@microchip.com>
>>>
>>> Using Clement's new validation callbacks, support checking that
>>> dependencies have been satisfied for the vector crpyto extensions.
>>> Currently riscv_isa_extension_available(<vector crypto>) will return
>>> true on systems that support the extensions but vector itself has been
>>> disabled by the kernel, adding validation callbacks will prevent such a
>>> scenario from occuring and make the behaviour of the extension detection
>>> functions more consistent with user expectations - it's not expected to
>>> have to check for vector AND the specific crypto extension.
>>>
>>> The 1.0.0 Vector crypto spec states:
>>> 	The Zvknhb and Zvbc Vector Crypto Extensions --and accordingly
>>> 	the composite extensions Zvkn and Zvks-- require a Zve64x base,
>>> 	or application ("V") base Vector Extension. All of the other
>>> 	Vector Crypto Extensions can be built on any embedded (Zve*) or
>>> 	application ("V") base Vector Extension.
>>> and this could be used as the basis for checking that the correct base
>>> for individual crypto extensions, but that's not really the kernel's job
>>> in my opinion and it is sufficient to leave that sort of precision to
>>> the dt-bindings. The kernel only needs to make sure that vector, in some
>>> form, is available.
>>>
>>> Since vector will now be disabled proactively, there's no need to clear
>>> the bit in elf_hwcap in riscv_fill_hwcap() any longer.
>>
>> To which part of the commit does this refer to ?
> 
> Copy-paste mistake when splitting in two, whoops.
> 
>>> @@ -397,8 +414,8 @@ const struct riscv_isa_ext_data riscv_isa_ext[] = {
>>>  	__RISCV_ISA_EXT_DATA(zksed, RISCV_ISA_EXT_ZKSED),
>>>  	__RISCV_ISA_EXT_DATA(zksh, RISCV_ISA_EXT_ZKSH),
>>>  	__RISCV_ISA_EXT_DATA(ztso, RISCV_ISA_EXT_ZTSO),
>>> -	__RISCV_ISA_EXT_SUPERSET(zvbb, RISCV_ISA_EXT_ZVBB, riscv_zvbb_exts),
>>> -	__RISCV_ISA_EXT_DATA(zvbc, RISCV_ISA_EXT_ZVBC),
>>> +	__RISCV_ISA_EXT_SUPERSET_VALIDATE(zvbb, RISCV_ISA_EXT_ZVBB, riscv_zvbb_exts, riscv_ext_vector_x_validate),
>>> +	__RISCV_ISA_EXT_DATA_VALIDATE(zvbc, RISCV_ISA_EXT_ZVBC, riscv_ext_vector_crypto_validate),
> 
>>
>> I'm not sure if I already made that comment, so here we go again.
>> Shouldn't Zvbb use riscv_ext_vector_crypto_validate() as well ?  The
>> spec states that Zvbb is a superset of Zvkb and Zvkb uses the
>> riscv_ext_vector_crypto_validate() validation callback. I guess Zvbc
>> should also use it based on your spec excerpt in the commmit log.
> 
> Zvbc does use it, no? I'll amend the Zvbb one, there should only be two
> users of the "x" variant.

Oh yes Zvbc is already ok, forget that then.

Clément

Re: [PATCH v3 2/6] RISC-V: add vector crypto extension validation checks

[Eric Biggers]

On Wed, Feb 05, 2025 at 04:05:08PM +0000, Conor Dooley wrote:
> The 1.0.0 Vector crypto spec states:
> 	The Zvknhb and Zvbc Vector Crypto Extensions --and accordingly
> 	the composite extensions Zvkn and Zvks-- require a Zve64x base,
> 	or application ("V") base Vector Extension. All of the other
> 	Vector Crypto Extensions can be built on any embedded (Zve*) or
> 	application ("V") base Vector Extension.

As previously discussed, the above paragraph incorrectly lists the set of crypto
extensions that require support for 64-bit elements.  I have fixed this in the
latest RISC-V ISA manual.  It looks like this patch would still do the same
thing either way, since it actually just checks that vector is available in some
form.  But this is not the best version of the manual to quote from.

- Eric

Re: [PATCH v3 2/6] RISC-V: add vector crypto extension validation checks

[Conor Dooley]

[-- Attachment #1: Type: text/plain, Size: 1066 bytes --]

On Thu, Feb 06, 2025 at 12:32:49PM -0800, Eric Biggers wrote:
> On Wed, Feb 05, 2025 at 04:05:08PM +0000, Conor Dooley wrote:
> > The 1.0.0 Vector crypto spec states:
> > 	The Zvknhb and Zvbc Vector Crypto Extensions --and accordingly
> > 	the composite extensions Zvkn and Zvks-- require a Zve64x base,
> > 	or application ("V") base Vector Extension. All of the other
> > 	Vector Crypto Extensions can be built on any embedded (Zve*) or
> > 	application ("V") base Vector Extension.
> 
> As previously discussed, the above paragraph incorrectly lists the set of crypto
> extensions that require support for 64-bit elements.  I have fixed this in the
> latest RISC-V ISA manual.  It looks like this patch would still do the same
> thing either way, since it actually just checks that vector is available in some
> form.  But this is not the best version of the manual to quote from.

/sigh, I updated the binding commit message but not the code one. That
one should probably change too, given that's now merged.
That's a stupid oversight, thanks.

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Re: [PATCH v3 2/6] RISC-V: add vector crypto extension validation checks

[Clément Léger]

On 05/02/2025 17:05, Conor Dooley wrote:
> From: Conor Dooley <conor.dooley@microchip.com>
> 
> Using Clement's new validation callbacks, support checking that
> dependencies have been satisfied for the vector crpyto extensions.
> Currently riscv_isa_extension_available(<vector crypto>) will return
> true on systems that support the extensions but vector itself has been
> disabled by the kernel, adding validation callbacks will prevent such a
> scenario from occuring and make the behaviour of the extension detection
> functions more consistent with user expectations - it's not expected to
> have to check for vector AND the specific crypto extension.
> 
> The 1.0.0 Vector crypto spec states:
> 	The Zvknhb and Zvbc Vector Crypto Extensions --and accordingly
> 	the composite extensions Zvkn and Zvks-- require a Zve64x base,
> 	or application ("V") base Vector Extension. All of the other
> 	Vector Crypto Extensions can be built on any embedded (Zve*) or
> 	application ("V") base Vector Extension.
> and this could be used as the basis for checking that the correct base
> for individual crypto extensions, but that's not really the kernel's job
> in my opinion and it is sufficient to leave that sort of precision to
> the dt-bindings. The kernel only needs to make sure that vector, in some
> form, is available.
> 
> Since vector will now be disabled proactively, there's no need to clear
> the bit in elf_hwcap in riscv_fill_hwcap() any longer.
> 
> Link: https://github.com/riscv/riscv-crypto/releases/tag/v1.0.0
> Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
> ---
>  arch/riscv/kernel/cpufeature.c | 49 +++++++++++++++++++++++-----------
>  1 file changed, 33 insertions(+), 16 deletions(-)
> 
> diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
> index 40a24b08d905..1c148ecea612 100644
> --- a/arch/riscv/kernel/cpufeature.c
> +++ b/arch/riscv/kernel/cpufeature.c
> @@ -138,6 +138,23 @@ static int riscv_ext_vector_float_validate(const struct riscv_isa_ext_data *data
>  	return 0;
>  }
>  
> +static int riscv_ext_vector_crypto_validate(const struct riscv_isa_ext_data *data,
> +					    const unsigned long *isa_bitmap)
> +{
> +	if (!IS_ENABLED(CONFIG_RISCV_ISA_V))
> +		return -EINVAL;
> +
> +	/*
> +	 * It isn't the kernel's job to check that the binding is correct, so
> +	 * it should be enough to check that any of the vector extensions are
> +	 * enabled, which in-turn means that vector is usable in this kernel
> +	 */
> +	if (!__riscv_isa_extension_available(isa_bitmap, RISCV_ISA_EXT_ZVE32X))
> +		return -EINVAL;

After a second thought, I think it should be this:

if (__riscv_isa_extension_available(isa_bitmap, RISCV_ISA_EXT_ZVE32X))
	return 0;

return -EPROBEDEFER;

Extensions can be enabled later (but can not be "reverted") so check for
the extension to be present (in which case it's ok), or wait for it to
be (potentially) enabled.

Thanks,

Clément

> +
> +	return 0;
> +}

> +
>  static int riscv_ext_zca_depends(const struct riscv_isa_ext_data *data,
>  				 const unsigned long *isa_bitmap)
>  {
> @@ -397,8 +414,8 @@ const struct riscv_isa_ext_data riscv_isa_ext[] = {
>  	__RISCV_ISA_EXT_DATA(zksed, RISCV_ISA_EXT_ZKSED),
>  	__RISCV_ISA_EXT_DATA(zksh, RISCV_ISA_EXT_ZKSH),
>  	__RISCV_ISA_EXT_DATA(ztso, RISCV_ISA_EXT_ZTSO),
> -	__RISCV_ISA_EXT_SUPERSET(zvbb, RISCV_ISA_EXT_ZVBB, riscv_zvbb_exts),
> -	__RISCV_ISA_EXT_DATA(zvbc, RISCV_ISA_EXT_ZVBC),
> +	__RISCV_ISA_EXT_SUPERSET_VALIDATE(zvbb, RISCV_ISA_EXT_ZVBB, riscv_zvbb_exts, riscv_ext_vector_x_validate),
> +	__RISCV_ISA_EXT_DATA_VALIDATE(zvbc, RISCV_ISA_EXT_ZVBC, riscv_ext_vector_crypto_validate),
>  	__RISCV_ISA_EXT_SUPERSET_VALIDATE(zve32f, RISCV_ISA_EXT_ZVE32F, riscv_zve32f_exts, riscv_ext_vector_float_validate),
>  	__RISCV_ISA_EXT_DATA_VALIDATE(zve32x, RISCV_ISA_EXT_ZVE32X, riscv_ext_vector_x_validate),
>  	__RISCV_ISA_EXT_SUPERSET_VALIDATE(zve64d, RISCV_ISA_EXT_ZVE64D, riscv_zve64d_exts, riscv_ext_vector_float_validate),
> @@ -406,20 +423,20 @@ const struct riscv_isa_ext_data riscv_isa_ext[] = {
>  	__RISCV_ISA_EXT_SUPERSET_VALIDATE(zve64x, RISCV_ISA_EXT_ZVE64X, riscv_zve64x_exts, riscv_ext_vector_x_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),
> -	__RISCV_ISA_EXT_DATA(zvkg, RISCV_ISA_EXT_ZVKG),
> -	__RISCV_ISA_EXT_BUNDLE(zvkn, riscv_zvkn_bundled_exts),
> -	__RISCV_ISA_EXT_BUNDLE(zvknc, riscv_zvknc_bundled_exts),
> -	__RISCV_ISA_EXT_DATA(zvkned, RISCV_ISA_EXT_ZVKNED),
> -	__RISCV_ISA_EXT_BUNDLE(zvkng, riscv_zvkng_bundled_exts),
> -	__RISCV_ISA_EXT_DATA(zvknha, RISCV_ISA_EXT_ZVKNHA),
> -	__RISCV_ISA_EXT_DATA(zvknhb, RISCV_ISA_EXT_ZVKNHB),
> -	__RISCV_ISA_EXT_BUNDLE(zvks, riscv_zvks_bundled_exts),
> -	__RISCV_ISA_EXT_BUNDLE(zvksc, riscv_zvksc_bundled_exts),
> -	__RISCV_ISA_EXT_DATA(zvksed, RISCV_ISA_EXT_ZVKSED),
> -	__RISCV_ISA_EXT_DATA(zvksh, RISCV_ISA_EXT_ZVKSH),
> -	__RISCV_ISA_EXT_BUNDLE(zvksg, riscv_zvksg_bundled_exts),
> -	__RISCV_ISA_EXT_DATA(zvkt, RISCV_ISA_EXT_ZVKT),
> +	__RISCV_ISA_EXT_DATA_VALIDATE(zvkb, RISCV_ISA_EXT_ZVKB, riscv_ext_vector_crypto_validate),
> +	__RISCV_ISA_EXT_DATA_VALIDATE(zvkg, RISCV_ISA_EXT_ZVKG, riscv_ext_vector_crypto_validate),
> +	__RISCV_ISA_EXT_BUNDLE_VALIDATE(zvkn, riscv_zvkn_bundled_exts, riscv_ext_vector_crypto_validate),
> +	__RISCV_ISA_EXT_BUNDLE_VALIDATE(zvknc, riscv_zvknc_bundled_exts, riscv_ext_vector_crypto_validate),
> +	__RISCV_ISA_EXT_DATA_VALIDATE(zvkned, RISCV_ISA_EXT_ZVKNED, riscv_ext_vector_crypto_validate),
> +	__RISCV_ISA_EXT_BUNDLE_VALIDATE(zvkng, riscv_zvkng_bundled_exts, riscv_ext_vector_crypto_validate),
> +	__RISCV_ISA_EXT_DATA_VALIDATE(zvknha, RISCV_ISA_EXT_ZVKNHA, riscv_ext_vector_crypto_validate),
> +	__RISCV_ISA_EXT_DATA_VALIDATE(zvknhb, RISCV_ISA_EXT_ZVKNHB, riscv_ext_vector_crypto_validate),
> +	__RISCV_ISA_EXT_BUNDLE_VALIDATE(zvks, riscv_zvks_bundled_exts, riscv_ext_vector_crypto_validate),
> +	__RISCV_ISA_EXT_BUNDLE_VALIDATE(zvksc, riscv_zvksc_bundled_exts, riscv_ext_vector_crypto_validate),
> +	__RISCV_ISA_EXT_DATA_VALIDATE(zvksed, RISCV_ISA_EXT_ZVKSED, riscv_ext_vector_crypto_validate),
> +	__RISCV_ISA_EXT_DATA_VALIDATE(zvksh, RISCV_ISA_EXT_ZVKSH, riscv_ext_vector_crypto_validate),
> +	__RISCV_ISA_EXT_BUNDLE_VALIDATE(zvksg, riscv_zvksg_bundled_exts, riscv_ext_vector_crypto_validate),
> +	__RISCV_ISA_EXT_DATA_VALIDATE(zvkt, RISCV_ISA_EXT_ZVKT, riscv_ext_vector_crypto_validate),
>  	__RISCV_ISA_EXT_DATA(smaia, RISCV_ISA_EXT_SMAIA),
>  	__RISCV_ISA_EXT_DATA(smmpm, RISCV_ISA_EXT_SMMPM),
>  	__RISCV_ISA_EXT_SUPERSET(smnpm, RISCV_ISA_EXT_SMNPM, riscv_xlinuxenvcfg_exts),

Re: [PATCH v3 1/6] RISC-V: add vector extension validation checks

[Clément Léger]

On 05/02/2025 17:05, Conor Dooley wrote:
> From: Conor Dooley <conor.dooley@microchip.com>
> 
> Using Clement's new validation callbacks, support checking that
> dependencies have been satisfied for the vector extensions. From the
> kernel's perfective, it's not required to differentiate between the
> conditions for all the various vector subsets - it's the firmware's job
> to not report impossible combinations. Instead, the kernel only has to
> check that the correct config options are enabled and to enforce its
> requirement of the d extension being present for FPU support.
> 
> Since vector will now be disabled proactively, there's no need to clear
> the bit in elf_hwcap in riscv_fill_hwcap() any longer.
> 
> Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
> ---
>  arch/riscv/include/asm/cpufeature.h |  3 ++
>  arch/riscv/kernel/cpufeature.c      | 57 +++++++++++++++++++----------
>  2 files changed, 40 insertions(+), 20 deletions(-)
> 
> diff --git a/arch/riscv/include/asm/cpufeature.h b/arch/riscv/include/asm/cpufeature.h
> index 569140d6e639..5d9427ccbc7a 100644
> --- a/arch/riscv/include/asm/cpufeature.h
> +++ b/arch/riscv/include/asm/cpufeature.h
> @@ -56,6 +56,9 @@ void __init riscv_user_isa_enable(void);
>  #define __RISCV_ISA_EXT_BUNDLE(_name, _bundled_exts) \
>  	_RISCV_ISA_EXT_DATA(_name, RISCV_ISA_EXT_INVALID, _bundled_exts, \
>  			    ARRAY_SIZE(_bundled_exts), NULL)
> +#define __RISCV_ISA_EXT_BUNDLE_VALIDATE(_name, _bundled_exts, _validate) \
> +	_RISCV_ISA_EXT_DATA(_name, RISCV_ISA_EXT_INVALID, _bundled_exts, \
> +			    ARRAY_SIZE(_bundled_exts), _validate)
>  
>  /* Used to declare extensions that are a superset of other extensions (Zvbb for instance) */
>  #define __RISCV_ISA_EXT_SUPERSET(_name, _id, _sub_exts) \
> diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
> index c6ba750536c3..40a24b08d905 100644
> --- a/arch/riscv/kernel/cpufeature.c
> +++ b/arch/riscv/kernel/cpufeature.c
> @@ -109,6 +109,35 @@ static int riscv_ext_zicboz_validate(const struct riscv_isa_ext_data *data,
>  	return 0;
>  }
>  
> +static int riscv_ext_vector_x_validate(const struct riscv_isa_ext_data *data,
> +				       const unsigned long *isa_bitmap)
> +{
> +	if (!IS_ENABLED(CONFIG_RISCV_ISA_V))
> +		return -EINVAL;
> +
> +	return 0;
> +}
> +
> +static int riscv_ext_vector_float_validate(const struct riscv_isa_ext_data *data,
> +					   const unsigned long *isa_bitmap)
> +{
> +	if (!IS_ENABLED(CONFIG_RISCV_ISA_V))
> +		return -EINVAL;
> +
> +	if (!IS_ENABLED(CONFIG_FPU))
> +		return -EINVAL;
> +
> +	/*
> +	 * The kernel doesn't support systems that don't implement both of
> +	 * F and D, so if any of the vector extensions that do floating point
> +	 * are to be usable, both floating point extensions need to be usable.
> +	 */
> +	if (!__riscv_isa_extension_available(isa_bitmap, RISCV_ISA_EXT_d))
> +		return -EINVAL;
> +
> +	return 0;
> +}

I think this should also be modified to be like this:

  if (__riscv_isa_extension_available(isa_bitmap, RISCV_ISA_EXT_d))
	  return 0;

  return -EPROBEDEFER;

That won't actually change the way it works since RISCV_ISA_EXT_d (and
all single letter extensions) is always probed before the others though.

Clément

> +
>  static int riscv_ext_zca_depends(const struct riscv_isa_ext_data *data,
>  				 const unsigned long *isa_bitmap)
>  {
> @@ -326,12 +355,10 @@ const struct riscv_isa_ext_data riscv_isa_ext[] = {
>  	__RISCV_ISA_EXT_DATA(d, RISCV_ISA_EXT_d),
>  	__RISCV_ISA_EXT_DATA(q, RISCV_ISA_EXT_q),
>  	__RISCV_ISA_EXT_SUPERSET(c, RISCV_ISA_EXT_c, riscv_c_exts),
> -	__RISCV_ISA_EXT_SUPERSET(v, RISCV_ISA_EXT_v, riscv_v_exts),
> +	__RISCV_ISA_EXT_SUPERSET_VALIDATE(v, RISCV_ISA_EXT_v, riscv_v_exts, riscv_ext_vector_float_validate),
>  	__RISCV_ISA_EXT_DATA(h, RISCV_ISA_EXT_h),
> -	__RISCV_ISA_EXT_SUPERSET_VALIDATE(zicbom, RISCV_ISA_EXT_ZICBOM, riscv_xlinuxenvcfg_exts,
> -					  riscv_ext_zicbom_validate),
> -	__RISCV_ISA_EXT_SUPERSET_VALIDATE(zicboz, RISCV_ISA_EXT_ZICBOZ, riscv_xlinuxenvcfg_exts,
> -					  riscv_ext_zicboz_validate),
> +	__RISCV_ISA_EXT_SUPERSET_VALIDATE(zicbom, RISCV_ISA_EXT_ZICBOM, riscv_xlinuxenvcfg_exts, riscv_ext_zicbom_validate),
> +	__RISCV_ISA_EXT_SUPERSET_VALIDATE(zicboz, RISCV_ISA_EXT_ZICBOZ, riscv_xlinuxenvcfg_exts, riscv_ext_zicboz_validate),
>  	__RISCV_ISA_EXT_DATA(ziccrse, RISCV_ISA_EXT_ZICCRSE),
>  	__RISCV_ISA_EXT_DATA(zicntr, RISCV_ISA_EXT_ZICNTR),
>  	__RISCV_ISA_EXT_DATA(zicond, RISCV_ISA_EXT_ZICOND),
> @@ -372,11 +399,11 @@ const struct riscv_isa_ext_data riscv_isa_ext[] = {
>  	__RISCV_ISA_EXT_DATA(ztso, RISCV_ISA_EXT_ZTSO),
>  	__RISCV_ISA_EXT_SUPERSET(zvbb, RISCV_ISA_EXT_ZVBB, riscv_zvbb_exts),
>  	__RISCV_ISA_EXT_DATA(zvbc, RISCV_ISA_EXT_ZVBC),
> -	__RISCV_ISA_EXT_SUPERSET(zve32f, RISCV_ISA_EXT_ZVE32F, riscv_zve32f_exts),
> -	__RISCV_ISA_EXT_DATA(zve32x, RISCV_ISA_EXT_ZVE32X),
> -	__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_SUPERSET_VALIDATE(zve32f, RISCV_ISA_EXT_ZVE32F, riscv_zve32f_exts, riscv_ext_vector_float_validate),
> +	__RISCV_ISA_EXT_DATA_VALIDATE(zve32x, RISCV_ISA_EXT_ZVE32X, riscv_ext_vector_x_validate),
> +	__RISCV_ISA_EXT_SUPERSET_VALIDATE(zve64d, RISCV_ISA_EXT_ZVE64D, riscv_zve64d_exts, riscv_ext_vector_float_validate),
> +	__RISCV_ISA_EXT_SUPERSET_VALIDATE(zve64f, RISCV_ISA_EXT_ZVE64F, riscv_zve64f_exts, riscv_ext_vector_float_validate),
> +	__RISCV_ISA_EXT_SUPERSET_VALIDATE(zve64x, RISCV_ISA_EXT_ZVE64X, riscv_zve64x_exts, riscv_ext_vector_x_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),
> @@ -960,16 +987,6 @@ void __init riscv_fill_hwcap(void)
>  		riscv_v_setup_vsize();
>  	}
>  
> -	if (elf_hwcap & COMPAT_HWCAP_ISA_V) {
> -		/*
> -		 * ISA string in device tree might have 'v' flag, but
> -		 * CONFIG_RISCV_ISA_V is disabled in kernel.
> -		 * Clear V flag in elf_hwcap if CONFIG_RISCV_ISA_V is disabled.
> -		 */
> -		if (!IS_ENABLED(CONFIG_RISCV_ISA_V))
> -			elf_hwcap &= ~COMPAT_HWCAP_ISA_V;
> -	}
> -
>  	memset(print_str, 0, sizeof(print_str));
>  	for (i = 0, j = 0; i < NUM_ALPHA_EXTS; i++)
>  		if (riscv_isa[0] & BIT_MASK(i))

Re: [PATCH v3 3/6] RISC-V: add f & d extension validation checks

[Clément Léger]

On 05/02/2025 17:05, Conor Dooley wrote:
> From: Conor Dooley <conor.dooley@microchip.com>
> 
> Using Clement's new validation callbacks, support checking that
> dependencies have been satisfied for the floating point extensions.
> 
> The check for "d" might be slightly confusingly shorter than that of "f",
> despite "d" depending on "f". This is because the requirement that a
> hart supporting double precision must also support single precision,
> should be validated by dt-bindings etc, not the kernel but lack of
> support for single precision only is a limitation of the kernel.
> 
> Since vector will now be disabled proactively, there's no need to clear
> the bit in elf_hwcap in riscv_fill_hwcap() any longer.
> 
> Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
> ---
>  arch/riscv/kernel/cpufeature.c | 27 +++++++++++++++++++++++++--
>  1 file changed, 25 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
> index 1c148ecea612..ad4fbaa4ff0d 100644
> --- a/arch/riscv/kernel/cpufeature.c
> +++ b/arch/riscv/kernel/cpufeature.c
> @@ -109,6 +109,29 @@ static int riscv_ext_zicboz_validate(const struct riscv_isa_ext_data *data,
>  	return 0;
>  }
>  
> +static int riscv_ext_f_validate(const struct riscv_isa_ext_data *data,
> +				const unsigned long *isa_bitmap)
> +{
> +	if (!__riscv_isa_extension_available(isa_bitmap, RISCV_ISA_EXT_d)) {
> +		pr_warn_once("This kernel does not support systems with F but not D\n");
> +		return -EINVAL;
> +	}

While I tested to remove the RISCV_ISA_EXT_d from the input isa bitmap
and it worked, I didn't realized that it was due to the probe order of
single letter extensions. D is probed before F so that works as
expected. But returning -EPROBEDEFER would not allow to display the
warn_once or wrongly display it if D was not yet probed. So I'm inclined
to keep it as is and rely on probe order (a bit fragile but for single
letter extensions, that seems acceptable).

> +
> +	if (!IS_ENABLED(CONFIG_FPU))
> +		return -EINVAL;

I would have actually move that chunk before the
__riscv_isa_extension_available() check so that the whole function body
is elided if FPU is disabled.

Clément

> +
> +	return 0;
> +}

> +
> +static int riscv_ext_d_validate(const struct riscv_isa_ext_data *data,
> +				const unsigned long *isa_bitmap)
> +{
> +	if (!IS_ENABLED(CONFIG_FPU))
> +		return -EINVAL;
> +
> +	return 0;
> +}
> +
>  static int riscv_ext_vector_x_validate(const struct riscv_isa_ext_data *data,
>  				       const unsigned long *isa_bitmap)
>  {
> @@ -368,8 +391,8 @@ const struct riscv_isa_ext_data riscv_isa_ext[] = {
>  	__RISCV_ISA_EXT_DATA(i, RISCV_ISA_EXT_i),
>  	__RISCV_ISA_EXT_DATA(m, RISCV_ISA_EXT_m),
>  	__RISCV_ISA_EXT_DATA(a, RISCV_ISA_EXT_a),
> -	__RISCV_ISA_EXT_DATA(f, RISCV_ISA_EXT_f),
> -	__RISCV_ISA_EXT_DATA(d, RISCV_ISA_EXT_d),
> +	__RISCV_ISA_EXT_DATA_VALIDATE(f, RISCV_ISA_EXT_f, riscv_ext_f_validate),
> +	__RISCV_ISA_EXT_DATA_VALIDATE(d, RISCV_ISA_EXT_d, riscv_ext_d_validate),
>  	__RISCV_ISA_EXT_DATA(q, RISCV_ISA_EXT_q),
>  	__RISCV_ISA_EXT_SUPERSET(c, RISCV_ISA_EXT_c, riscv_c_exts),
>  	__RISCV_ISA_EXT_SUPERSET_VALIDATE(v, RISCV_ISA_EXT_v, riscv_v_exts, riscv_ext_vector_float_validate),

Re: [PATCH v3 3/6] RISC-V: add f & d extension validation checks

[Conor Dooley]

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On Tue, Feb 11, 2025 at 11:22:13AM +0100, Clément Léger wrote:
> 
> 
> On 05/02/2025 17:05, Conor Dooley wrote:
> > From: Conor Dooley <conor.dooley@microchip.com>
> > 
> > Using Clement's new validation callbacks, support checking that
> > dependencies have been satisfied for the floating point extensions.
> > 
> > The check for "d" might be slightly confusingly shorter than that of "f",
> > despite "d" depending on "f". This is because the requirement that a
> > hart supporting double precision must also support single precision,
> > should be validated by dt-bindings etc, not the kernel but lack of
> > support for single precision only is a limitation of the kernel.
> > 
> > Since vector will now be disabled proactively, there's no need to clear
> > the bit in elf_hwcap in riscv_fill_hwcap() any longer.
> > 
> > Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
> > ---
> >  arch/riscv/kernel/cpufeature.c | 27 +++++++++++++++++++++++++--
> >  1 file changed, 25 insertions(+), 2 deletions(-)
> > 
> > diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
> > index 1c148ecea612..ad4fbaa4ff0d 100644
> > --- a/arch/riscv/kernel/cpufeature.c
> > +++ b/arch/riscv/kernel/cpufeature.c
> > @@ -109,6 +109,29 @@ static int riscv_ext_zicboz_validate(const struct riscv_isa_ext_data *data,
> >  	return 0;
> >  }
> >  
> > +static int riscv_ext_f_validate(const struct riscv_isa_ext_data *data,
> > +				const unsigned long *isa_bitmap)
> > +{
> > +	if (!__riscv_isa_extension_available(isa_bitmap, RISCV_ISA_EXT_d)) {
> > +		pr_warn_once("This kernel does not support systems with F but not D\n");
> > +		return -EINVAL;
> > +	}
> 
> While I tested to remove the RISCV_ISA_EXT_d from the input isa bitmap
> and it worked, I didn't realized that it was due to the probe order of
> single letter extensions. D is probed before F so that works as
> expected. But returning -EPROBEDEFER would not allow to display the
> warn_once or wrongly display it if D was not yet probed. So I'm inclined
> to keep it as is and rely on probe order (a bit fragile but for single
> letter extensions, that seems acceptable).

I guess it's worth adding a comment to that effect.

> > +
> > +	if (!IS_ENABLED(CONFIG_FPU))
> > +		return -EINVAL;
> 
> I would have actually move that chunk before the
> __riscv_isa_extension_available() check so that the whole function body
> is elided if FPU is disabled.

I think you're right, but for another reason too - warning when someone
has turned off CONIFG_FPU doesn't make sense.

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Re: [PATCH v3 2/6] RISC-V: add vector crypto extension validation checks

[Conor Dooley]

[-- Attachment #1: Type: text/plain, Size: 3398 bytes --]

On Tue, Feb 11, 2025 at 09:45:44AM +0100, Clément Léger wrote:
> 
> 
> On 05/02/2025 17:05, Conor Dooley wrote:
> > From: Conor Dooley <conor.dooley@microchip.com>
> > 
> > Using Clement's new validation callbacks, support checking that
> > dependencies have been satisfied for the vector crpyto extensions.
> > Currently riscv_isa_extension_available(<vector crypto>) will return
> > true on systems that support the extensions but vector itself has been
> > disabled by the kernel, adding validation callbacks will prevent such a
> > scenario from occuring and make the behaviour of the extension detection
> > functions more consistent with user expectations - it's not expected to
> > have to check for vector AND the specific crypto extension.
> > 
> > The 1.0.0 Vector crypto spec states:
> > 	The Zvknhb and Zvbc Vector Crypto Extensions --and accordingly
> > 	the composite extensions Zvkn and Zvks-- require a Zve64x base,
> > 	or application ("V") base Vector Extension. All of the other
> > 	Vector Crypto Extensions can be built on any embedded (Zve*) or
> > 	application ("V") base Vector Extension.
> > and this could be used as the basis for checking that the correct base
> > for individual crypto extensions, but that's not really the kernel's job
> > in my opinion and it is sufficient to leave that sort of precision to
> > the dt-bindings. The kernel only needs to make sure that vector, in some
> > form, is available.
> > 
> > Since vector will now be disabled proactively, there's no need to clear
> > the bit in elf_hwcap in riscv_fill_hwcap() any longer.
> > 
> > Link: https://github.com/riscv/riscv-crypto/releases/tag/v1.0.0
> > Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
> > ---
> >  arch/riscv/kernel/cpufeature.c | 49 +++++++++++++++++++++++-----------
> >  1 file changed, 33 insertions(+), 16 deletions(-)
> > 
> > diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
> > index 40a24b08d905..1c148ecea612 100644
> > --- a/arch/riscv/kernel/cpufeature.c
> > +++ b/arch/riscv/kernel/cpufeature.c
> > @@ -138,6 +138,23 @@ static int riscv_ext_vector_float_validate(const struct riscv_isa_ext_data *data
> >  	return 0;
> >  }
> >  
> > +static int riscv_ext_vector_crypto_validate(const struct riscv_isa_ext_data *data,
> > +					    const unsigned long *isa_bitmap)
> > +{
> > +	if (!IS_ENABLED(CONFIG_RISCV_ISA_V))
> > +		return -EINVAL;
> > +
> > +	/*
> > +	 * It isn't the kernel's job to check that the binding is correct, so
> > +	 * it should be enough to check that any of the vector extensions are
> > +	 * enabled, which in-turn means that vector is usable in this kernel
> > +	 */
> > +	if (!__riscv_isa_extension_available(isa_bitmap, RISCV_ISA_EXT_ZVE32X))
> > +		return -EINVAL;
> 
> After a second thought, I think it should be this:
> 
> if (__riscv_isa_extension_available(isa_bitmap, RISCV_ISA_EXT_ZVE32X))
> 	return 0;
> 
> return -EPROBEDEFER;
> 
> Extensions can be enabled later (but can not be "reverted") so check for
> the extension to be present (in which case it's ok), or wait for it to
> be (potentially) enabled.

Ah, of course it is operating on the /resolved/ isa, not the source one.
Makes me thing the parameter of all the validate callbacks should be
"resolved_isa_bitmap" instead of "isa_bitmap" to make things clearer?


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Re: [PATCH v3 2/6] RISC-V: add vector crypto extension validation checks

[Clément Léger]

On 11/02/2025 13:34, Conor Dooley wrote:
> On Tue, Feb 11, 2025 at 09:45:44AM +0100, Clément Léger wrote:
>>
>>
>> On 05/02/2025 17:05, Conor Dooley wrote:
>>> From: Conor Dooley <conor.dooley@microchip.com>
>>>
>>> Using Clement's new validation callbacks, support checking that
>>> dependencies have been satisfied for the vector crpyto extensions.
>>> Currently riscv_isa_extension_available(<vector crypto>) will return
>>> true on systems that support the extensions but vector itself has been
>>> disabled by the kernel, adding validation callbacks will prevent such a
>>> scenario from occuring and make the behaviour of the extension detection
>>> functions more consistent with user expectations - it's not expected to
>>> have to check for vector AND the specific crypto extension.
>>>
>>> The 1.0.0 Vector crypto spec states:
>>> 	The Zvknhb and Zvbc Vector Crypto Extensions --and accordingly
>>> 	the composite extensions Zvkn and Zvks-- require a Zve64x base,
>>> 	or application ("V") base Vector Extension. All of the other
>>> 	Vector Crypto Extensions can be built on any embedded (Zve*) or
>>> 	application ("V") base Vector Extension.
>>> and this could be used as the basis for checking that the correct base
>>> for individual crypto extensions, but that's not really the kernel's job
>>> in my opinion and it is sufficient to leave that sort of precision to
>>> the dt-bindings. The kernel only needs to make sure that vector, in some
>>> form, is available.
>>>
>>> Since vector will now be disabled proactively, there's no need to clear
>>> the bit in elf_hwcap in riscv_fill_hwcap() any longer.
>>>
>>> Link: https://github.com/riscv/riscv-crypto/releases/tag/v1.0.0
>>> Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
>>> ---
>>>  arch/riscv/kernel/cpufeature.c | 49 +++++++++++++++++++++++-----------
>>>  1 file changed, 33 insertions(+), 16 deletions(-)
>>>
>>> diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
>>> index 40a24b08d905..1c148ecea612 100644
>>> --- a/arch/riscv/kernel/cpufeature.c
>>> +++ b/arch/riscv/kernel/cpufeature.c
>>> @@ -138,6 +138,23 @@ static int riscv_ext_vector_float_validate(const struct riscv_isa_ext_data *data
>>>  	return 0;
>>>  }
>>>  
>>> +static int riscv_ext_vector_crypto_validate(const struct riscv_isa_ext_data *data,
>>> +					    const unsigned long *isa_bitmap)
>>> +{
>>> +	if (!IS_ENABLED(CONFIG_RISCV_ISA_V))
>>> +		return -EINVAL;
>>> +
>>> +	/*
>>> +	 * It isn't the kernel's job to check that the binding is correct, so
>>> +	 * it should be enough to check that any of the vector extensions are
>>> +	 * enabled, which in-turn means that vector is usable in this kernel
>>> +	 */
>>> +	if (!__riscv_isa_extension_available(isa_bitmap, RISCV_ISA_EXT_ZVE32X))
>>> +		return -EINVAL;
>>
>> After a second thought, I think it should be this:
>>
>> if (__riscv_isa_extension_available(isa_bitmap, RISCV_ISA_EXT_ZVE32X))
>> 	return 0;
>>
>> return -EPROBEDEFER;
>>
>> Extensions can be enabled later (but can not be "reverted") so check for
>> the extension to be present (in which case it's ok), or wait for it to
>> be (potentially) enabled.
> 
> Ah, of course it is operating on the /resolved/ isa, not the source one.
> Makes me thing the parameter of all the validate callbacks should be
> "resolved_isa_bitmap" instead of "isa_bitmap" to make things clearer?

Yeah that would be helpful I guess.

Clément

Re: [PATCH v3 1/6] RISC-V: add vector extension validation checks

[Conor Dooley]

[-- Attachment #1: Type: text/plain, Size: 3708 bytes --]

On Tue, Feb 11, 2025 at 11:16:45AM +0100, Clément Léger wrote:
> 
> 
> On 05/02/2025 17:05, Conor Dooley wrote:
> > From: Conor Dooley <conor.dooley@microchip.com>
> > 
> > Using Clement's new validation callbacks, support checking that
> > dependencies have been satisfied for the vector extensions. From the
> > kernel's perfective, it's not required to differentiate between the
> > conditions for all the various vector subsets - it's the firmware's job
> > to not report impossible combinations. Instead, the kernel only has to
> > check that the correct config options are enabled and to enforce its
> > requirement of the d extension being present for FPU support.
> > 
> > Since vector will now be disabled proactively, there's no need to clear
> > the bit in elf_hwcap in riscv_fill_hwcap() any longer.
> > 
> > Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
> > ---
> >  arch/riscv/include/asm/cpufeature.h |  3 ++
> >  arch/riscv/kernel/cpufeature.c      | 57 +++++++++++++++++++----------
> >  2 files changed, 40 insertions(+), 20 deletions(-)
> > 
> > diff --git a/arch/riscv/include/asm/cpufeature.h b/arch/riscv/include/asm/cpufeature.h
> > index 569140d6e639..5d9427ccbc7a 100644
> > --- a/arch/riscv/include/asm/cpufeature.h
> > +++ b/arch/riscv/include/asm/cpufeature.h
> > @@ -56,6 +56,9 @@ void __init riscv_user_isa_enable(void);
> >  #define __RISCV_ISA_EXT_BUNDLE(_name, _bundled_exts) \
> >  	_RISCV_ISA_EXT_DATA(_name, RISCV_ISA_EXT_INVALID, _bundled_exts, \
> >  			    ARRAY_SIZE(_bundled_exts), NULL)
> > +#define __RISCV_ISA_EXT_BUNDLE_VALIDATE(_name, _bundled_exts, _validate) \
> > +	_RISCV_ISA_EXT_DATA(_name, RISCV_ISA_EXT_INVALID, _bundled_exts, \
> > +			    ARRAY_SIZE(_bundled_exts), _validate)
> >  
> >  /* Used to declare extensions that are a superset of other extensions (Zvbb for instance) */
> >  #define __RISCV_ISA_EXT_SUPERSET(_name, _id, _sub_exts) \
> > diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
> > index c6ba750536c3..40a24b08d905 100644
> > --- a/arch/riscv/kernel/cpufeature.c
> > +++ b/arch/riscv/kernel/cpufeature.c
> > @@ -109,6 +109,35 @@ static int riscv_ext_zicboz_validate(const struct riscv_isa_ext_data *data,
> >  	return 0;
> >  }
> >  
> > +static int riscv_ext_vector_x_validate(const struct riscv_isa_ext_data *data,
> > +				       const unsigned long *isa_bitmap)
> > +{
> > +	if (!IS_ENABLED(CONFIG_RISCV_ISA_V))
> > +		return -EINVAL;
> > +
> > +	return 0;
> > +}
> > +
> > +static int riscv_ext_vector_float_validate(const struct riscv_isa_ext_data *data,
> > +					   const unsigned long *isa_bitmap)
> > +{
> > +	if (!IS_ENABLED(CONFIG_RISCV_ISA_V))
> > +		return -EINVAL;
> > +
> > +	if (!IS_ENABLED(CONFIG_FPU))
> > +		return -EINVAL;
> > +
> > +	/*
> > +	 * The kernel doesn't support systems that don't implement both of
> > +	 * F and D, so if any of the vector extensions that do floating point
> > +	 * are to be usable, both floating point extensions need to be usable.
> > +	 */
> > +	if (!__riscv_isa_extension_available(isa_bitmap, RISCV_ISA_EXT_d))
> > +		return -EINVAL;
> > +
> > +	return 0;
> > +}
> 
> I think this should also be modified to be like this:
> 
>   if (__riscv_isa_extension_available(isa_bitmap, RISCV_ISA_EXT_d))
> 	  return 0;
> 
>   return -EPROBEDEFER;
> 
> That won't actually change the way it works since RISCV_ISA_EXT_d (and
> all single letter extensions) is always probed before the others though.

I don't think so, there's no point deferring since we know that the
extensions this is used for cannot become true afterwards. I'll add a
comment justifying it.

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