1 files changed, 239 insertions, 89 deletions

diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
index 5ef48cb20ee1..0366dc3baf33 100644
--- a/arch/riscv/kernel/cpufeature.c
+++ b/arch/riscv/kernel/cpufeature.c
@@ -72,51 +72,89 @@ bool __riscv_isa_extension_available(const unsigned long *isa_bitmap, unsigned i
 }
 EXPORT_SYMBOL_GPL(__riscv_isa_extension_available);
 
-static bool riscv_isa_extension_check(int id)
+static int riscv_ext_zicbom_validate(const struct riscv_isa_ext_data *data,
+				     const unsigned long *isa_bitmap)
 {
-	switch (id) {
-	case RISCV_ISA_EXT_ZICBOM:
-		if (!riscv_cbom_block_size) {
-			pr_err("Zicbom detected in ISA string, disabling as no cbom-block-size found\n");
-			return false;
-		} else if (!is_power_of_2(riscv_cbom_block_size)) {
-			pr_err("Zicbom disabled as cbom-block-size present, but is not a power-of-2\n");
-			return false;
-		}
-		return true;
-	case RISCV_ISA_EXT_ZICBOZ:
-		if (!riscv_cboz_block_size) {
-			pr_err("Zicboz detected in ISA string, disabling as no cboz-block-size found\n");
-			return false;
-		} else if (!is_power_of_2(riscv_cboz_block_size)) {
-			pr_err("Zicboz disabled as cboz-block-size present, but is not a power-of-2\n");
-			return false;
-		}
-		return true;
-	case RISCV_ISA_EXT_INVALID:
-		return false;
+	if (!riscv_cbom_block_size) {
+		pr_err("Zicbom detected in ISA string, disabling as no cbom-block-size found\n");
+		return -EINVAL;
+	}
+	if (!is_power_of_2(riscv_cbom_block_size)) {
+		pr_err("Zicbom disabled as cbom-block-size present, but is not a power-of-2\n");
+		return -EINVAL;
 	}
+	return 0;
+}
 
-	return true;
+static int riscv_ext_zicboz_validate(const struct riscv_isa_ext_data *data,
+				     const unsigned long *isa_bitmap)
+{
+	if (!riscv_cboz_block_size) {
+		pr_err("Zicboz detected in ISA string, disabling as no cboz-block-size found\n");
+		return -EINVAL;
+	}
+	if (!is_power_of_2(riscv_cboz_block_size)) {
+		pr_err("Zicboz disabled as cboz-block-size present, but is not a power-of-2\n");
+		return -EINVAL;
+	}
+	return 0;
 }
 
-#define _RISCV_ISA_EXT_DATA(_name, _id, _subset_exts, _subset_exts_size) {	\
-	.name = #_name,								\
-	.property = #_name,							\
-	.id = _id,								\
-	.subset_ext_ids = _subset_exts,						\
-	.subset_ext_size = _subset_exts_size					\
+#define _RISCV_ISA_EXT_DATA(_name, _id, _subset_exts, _subset_exts_size, _validate) {	\
+	.name = #_name,									\
+	.property = #_name,								\
+	.id = _id,									\
+	.subset_ext_ids = _subset_exts,							\
+	.subset_ext_size = _subset_exts_size,						\
+	.validate = _validate								\
 }
 
-#define __RISCV_ISA_EXT_DATA(_name, _id) _RISCV_ISA_EXT_DATA(_name, _id, NULL, 0)
+#define __RISCV_ISA_EXT_DATA(_name, _id) _RISCV_ISA_EXT_DATA(_name, _id, NULL, 0, NULL)
+
+#define __RISCV_ISA_EXT_DATA_VALIDATE(_name, _id, _validate) \
+			_RISCV_ISA_EXT_DATA(_name, _id, NULL, 0, _validate)
 
 /* Used to declare pure "lasso" extension (Zk for instance) */
 #define __RISCV_ISA_EXT_BUNDLE(_name, _bundled_exts) \
-	_RISCV_ISA_EXT_DATA(_name, RISCV_ISA_EXT_INVALID, _bundled_exts, ARRAY_SIZE(_bundled_exts))
+	_RISCV_ISA_EXT_DATA(_name, RISCV_ISA_EXT_INVALID, _bundled_exts, \
+			    ARRAY_SIZE(_bundled_exts), NULL)
 
 /* Used to declare extensions that are a superset of other extensions (Zvbb for instance) */
 #define __RISCV_ISA_EXT_SUPERSET(_name, _id, _sub_exts) \
-	_RISCV_ISA_EXT_DATA(_name, _id, _sub_exts, ARRAY_SIZE(_sub_exts))
+	_RISCV_ISA_EXT_DATA(_name, _id, _sub_exts, ARRAY_SIZE(_sub_exts), NULL)
+#define __RISCV_ISA_EXT_SUPERSET_VALIDATE(_name, _id, _sub_exts, _validate) \
+	_RISCV_ISA_EXT_DATA(_name, _id, _sub_exts, ARRAY_SIZE(_sub_exts), _validate)
+
+static int riscv_ext_zca_depends(const struct riscv_isa_ext_data *data,
+				 const unsigned long *isa_bitmap)
+{
+	if (__riscv_isa_extension_available(isa_bitmap, RISCV_ISA_EXT_ZCA))
+		return 0;
+
+	return -EPROBE_DEFER;
+}
+static int riscv_ext_zcd_validate(const struct riscv_isa_ext_data *data,
+				  const unsigned long *isa_bitmap)
+{
+	if (__riscv_isa_extension_available(isa_bitmap, RISCV_ISA_EXT_ZCA) &&
+	    __riscv_isa_extension_available(isa_bitmap, RISCV_ISA_EXT_d))
+		return 0;
+
+	return -EPROBE_DEFER;
+}
+
+static int riscv_ext_zcf_validate(const struct riscv_isa_ext_data *data,
+				  const unsigned long *isa_bitmap)
+{
+	if (IS_ENABLED(CONFIG_64BIT))
+		return -EINVAL;
+
+	if (__riscv_isa_extension_available(isa_bitmap, RISCV_ISA_EXT_ZCA) &&
+	    __riscv_isa_extension_available(isa_bitmap, RISCV_ISA_EXT_f))
+		return 0;
+
+	return -EPROBE_DEFER;
+}
 
 static const unsigned int riscv_zk_bundled_exts[] = {
 	RISCV_ISA_EXT_ZBKB,
@@ -188,6 +226,40 @@ static const unsigned int riscv_zvbb_exts[] = {
 	RISCV_ISA_EXT_ZVKB
 };
 
+#define RISCV_ISA_EXT_ZVE64F_IMPLY_LIST	\
+	RISCV_ISA_EXT_ZVE64X,		\
+	RISCV_ISA_EXT_ZVE32F,		\
+	RISCV_ISA_EXT_ZVE32X
+
+#define RISCV_ISA_EXT_ZVE64D_IMPLY_LIST	\
+	RISCV_ISA_EXT_ZVE64F,		\
+	RISCV_ISA_EXT_ZVE64F_IMPLY_LIST
+
+#define RISCV_ISA_EXT_V_IMPLY_LIST	\
+	RISCV_ISA_EXT_ZVE64D,		\
+	RISCV_ISA_EXT_ZVE64D_IMPLY_LIST
+
+static const unsigned int riscv_zve32f_exts[] = {
+	RISCV_ISA_EXT_ZVE32X
+};
+
+static const unsigned int riscv_zve64f_exts[] = {
+	RISCV_ISA_EXT_ZVE64F_IMPLY_LIST
+};
+
+static const unsigned int riscv_zve64d_exts[] = {
+	RISCV_ISA_EXT_ZVE64D_IMPLY_LIST
+};
+
+static const unsigned int riscv_v_exts[] = {
+	RISCV_ISA_EXT_V_IMPLY_LIST
+};
+
+static const unsigned int riscv_zve64x_exts[] = {
+	RISCV_ISA_EXT_ZVE32X,
+	RISCV_ISA_EXT_ZVE64X
+};
+
 /*
  * While the [ms]envcfg CSRs were not defined until version 1.12 of the RISC-V
  * privileged ISA, the existence of the CSRs is implied by any extension which
@@ -199,6 +271,21 @@ static const unsigned int riscv_xlinuxenvcfg_exts[] = {
 };
 
 /*
+ * Zc* spec states that:
+ * - C always implies Zca
+ * - C+F implies Zcf (RV32 only)
+ * - C+D implies Zcd
+ *
+ * These extensions will be enabled and then validated depending on the
+ * availability of F/D RV32.
+ */
+static const unsigned int riscv_c_exts[] = {
+	RISCV_ISA_EXT_ZCA,
+	RISCV_ISA_EXT_ZCF,
+	RISCV_ISA_EXT_ZCD,
+};
+
+/*
  * The canonical order of ISA extension names in the ISA string is defined in
  * chapter 27 of the unprivileged specification.
  *
@@ -244,11 +331,13 @@ const struct riscv_isa_ext_data riscv_isa_ext[] = {
 	__RISCV_ISA_EXT_DATA(f, RISCV_ISA_EXT_f),
 	__RISCV_ISA_EXT_DATA(d, RISCV_ISA_EXT_d),
 	__RISCV_ISA_EXT_DATA(q, RISCV_ISA_EXT_q),
-	__RISCV_ISA_EXT_DATA(c, RISCV_ISA_EXT_c),
-	__RISCV_ISA_EXT_DATA(v, RISCV_ISA_EXT_v),
+	__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_DATA(h, RISCV_ISA_EXT_h),
-	__RISCV_ISA_EXT_SUPERSET(zicbom, RISCV_ISA_EXT_ZICBOM, riscv_xlinuxenvcfg_exts),
-	__RISCV_ISA_EXT_SUPERSET(zicboz, RISCV_ISA_EXT_ZICBOZ, riscv_xlinuxenvcfg_exts),
+	__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(zicntr, RISCV_ISA_EXT_ZICNTR),
 	__RISCV_ISA_EXT_DATA(zicond, RISCV_ISA_EXT_ZICOND),
 	__RISCV_ISA_EXT_DATA(zicsr, RISCV_ISA_EXT_ZICSR),
@@ -256,10 +345,17 @@ const struct riscv_isa_ext_data riscv_isa_ext[] = {
 	__RISCV_ISA_EXT_DATA(zihintntl, RISCV_ISA_EXT_ZIHINTNTL),
 	__RISCV_ISA_EXT_DATA(zihintpause, RISCV_ISA_EXT_ZIHINTPAUSE),
 	__RISCV_ISA_EXT_DATA(zihpm, RISCV_ISA_EXT_ZIHPM),
+	__RISCV_ISA_EXT_DATA(zimop, RISCV_ISA_EXT_ZIMOP),
 	__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(zfh, RISCV_ISA_EXT_ZFH),
 	__RISCV_ISA_EXT_DATA(zfhmin, RISCV_ISA_EXT_ZFHMIN),
+	__RISCV_ISA_EXT_DATA(zca, RISCV_ISA_EXT_ZCA),
+	__RISCV_ISA_EXT_DATA_VALIDATE(zcb, RISCV_ISA_EXT_ZCB, riscv_ext_zca_depends),
+	__RISCV_ISA_EXT_DATA_VALIDATE(zcd, RISCV_ISA_EXT_ZCD, riscv_ext_zcd_validate),
+	__RISCV_ISA_EXT_DATA_VALIDATE(zcf, RISCV_ISA_EXT_ZCF, riscv_ext_zcf_validate),
+	__RISCV_ISA_EXT_DATA_VALIDATE(zcmop, RISCV_ISA_EXT_ZCMOP, riscv_ext_zca_depends),
 	__RISCV_ISA_EXT_DATA(zba, RISCV_ISA_EXT_ZBA),
 	__RISCV_ISA_EXT_DATA(zbb, RISCV_ISA_EXT_ZBB),
 	__RISCV_ISA_EXT_DATA(zbc, RISCV_ISA_EXT_ZBC),
@@ -280,6 +376,11 @@ 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_DATA(zvfh, RISCV_ISA_EXT_ZVFH),
 	__RISCV_ISA_EXT_DATA(zvfhmin, RISCV_ISA_EXT_ZVFHMIN),
 	__RISCV_ISA_EXT_DATA(zvkb, RISCV_ISA_EXT_ZVKB),
@@ -309,33 +410,93 @@ const struct riscv_isa_ext_data riscv_isa_ext[] = {
 
 const size_t riscv_isa_ext_count = ARRAY_SIZE(riscv_isa_ext);
 
-static void __init match_isa_ext(const struct riscv_isa_ext_data *ext, const char *name,
-				 const char *name_end, struct riscv_isainfo *isainfo)
+static void riscv_isa_set_ext(const struct riscv_isa_ext_data *ext, unsigned long *bitmap)
 {
-	if ((name_end - name == strlen(ext->name)) &&
-	     !strncasecmp(name, ext->name, name_end - name)) {
-		/*
-		 * If this is a bundle, enable all the ISA extensions that
-		 * comprise the bundle.
-		 */
-		if (ext->subset_ext_size) {
-			for (int i = 0; i < ext->subset_ext_size; i++) {
-				if (riscv_isa_extension_check(ext->subset_ext_ids[i]))
-					set_bit(ext->subset_ext_ids[i], isainfo->isa);
+	if (ext->id != RISCV_ISA_EXT_INVALID)
+		set_bit(ext->id, bitmap);
+
+	for (int i = 0; i < ext->subset_ext_size; i++) {
+		if (ext->subset_ext_ids[i] != RISCV_ISA_EXT_INVALID)
+			set_bit(ext->subset_ext_ids[i], bitmap);
+	}
+}
+
+static const struct riscv_isa_ext_data *riscv_get_isa_ext_data(unsigned int ext_id)
+{
+	for (int i = 0; i < riscv_isa_ext_count; i++) {
+		if (riscv_isa_ext[i].id == ext_id)
+			return &riscv_isa_ext[i];
+	}
+
+	return NULL;
+}
+
+/*
+ * "Resolve" a source ISA bitmap into one that matches kernel configuration as
+ * well as correct extension dependencies. Some extensions depends on specific
+ * kernel configuration to be usable (V needs CONFIG_RISCV_ISA_V for instance)
+ * and this function will actually validate all the extensions provided in
+ * source_isa into the resolved_isa based on extensions validate() callbacks.
+ */
+static void __init riscv_resolve_isa(unsigned long *source_isa,
+				     unsigned long *resolved_isa, unsigned long *this_hwcap,
+				     unsigned long *isa2hwcap)
+{
+	bool loop;
+	const struct riscv_isa_ext_data *ext;
+	DECLARE_BITMAP(prev_resolved_isa, RISCV_ISA_EXT_MAX);
+	int max_loop_count = riscv_isa_ext_count, ret;
+	unsigned int bit;
+
+	do {
+		loop = false;
+		if (max_loop_count-- < 0) {
+			pr_err("Failed to reach a stable ISA state\n");
+			return;
+		}
+		bitmap_copy(prev_resolved_isa, resolved_isa, RISCV_ISA_EXT_MAX);
+		for_each_set_bit(bit, source_isa, RISCV_ISA_EXT_MAX) {
+			ext = riscv_get_isa_ext_data(bit);
+			if (!ext)
+				continue;
+
+			if (ext->validate) {
+				ret = ext->validate(ext, resolved_isa);
+				if (ret == -EPROBE_DEFER) {
+					loop = true;
+					continue;
+				} else if (ret) {
+					/* Disable the extension entirely */
+					clear_bit(ext->id, source_isa);
+					continue;
+				}
 			}
+
+			set_bit(ext->id, resolved_isa);
+			/* No need to keep it in source isa now that it is enabled */
+			clear_bit(ext->id, source_isa);
+
+			/* Single letter extensions get set in hwcap */
+			if (ext->id < RISCV_ISA_EXT_BASE)
+				*this_hwcap |= isa2hwcap[ext->id];
 		}
+	} while (loop && memcmp(prev_resolved_isa, resolved_isa, sizeof(prev_resolved_isa)));
+}
 
-		/*
-		 * This is valid even for bundle extensions which uses the RISCV_ISA_EXT_INVALID id
-		 * (rejected by riscv_isa_extension_check()).
-		 */
-		if (riscv_isa_extension_check(ext->id))
-			set_bit(ext->id, isainfo->isa);
+static void __init match_isa_ext(const char *name, const char *name_end, unsigned long *bitmap)
+{
+	for (int i = 0; i < riscv_isa_ext_count; i++) {
+		const struct riscv_isa_ext_data *ext = &riscv_isa_ext[i];
+
+		if ((name_end - name == strlen(ext->name)) &&
+		    !strncasecmp(name, ext->name, name_end - name)) {
+			riscv_isa_set_ext(ext, bitmap);
+			break;
+		}
 	}
 }
 
-static void __init riscv_parse_isa_string(unsigned long *this_hwcap, struct riscv_isainfo *isainfo,
-					  unsigned long *isa2hwcap, const char *isa)
+static void __init riscv_parse_isa_string(const char *isa, unsigned long *bitmap)
 {
 	/*
 	 * For all possible cpus, we have already validated in
@@ -348,7 +509,7 @@ static void __init riscv_parse_isa_string(unsigned long *this_hwcap, struct risc
 	while (*isa) {
 		const char *ext = isa++;
 		const char *ext_end = isa;
-		bool ext_long = false, ext_err = false;
+		bool ext_err = false;
 
 		switch (*ext) {
 		case 's':
@@ -388,7 +549,6 @@ static void __init riscv_parse_isa_string(unsigned long *this_hwcap, struct risc
 			 * character itself while eliminating the extensions version number.
 			 * A simple re-increment solves this problem.
 			 */
-			ext_long = true;
 			for (; *isa && *isa != '_'; ++isa)
 				if (unlikely(!isalnum(*isa)))
 					ext_err = true;
@@ -468,17 +628,8 @@ static void __init riscv_parse_isa_string(unsigned long *this_hwcap, struct risc
 
 		if (unlikely(ext_err))
 			continue;
-		if (!ext_long) {
-			int nr = tolower(*ext) - 'a';
 
-			if (riscv_isa_extension_check(nr)) {
-				*this_hwcap |= isa2hwcap[nr];
-				set_bit(nr, isainfo->isa);
-			}
-		} else {
-			for (int i = 0; i < riscv_isa_ext_count; i++)
-				match_isa_ext(&riscv_isa_ext[i], ext, ext_end, isainfo);
-		}
+		match_isa_ext(ext, ext_end, bitmap);
 	}
 }
 
@@ -505,6 +656,7 @@ static void __init riscv_fill_hwcap_from_isa_string(unsigned long *isa2hwcap)
 	for_each_possible_cpu(cpu) {
 		struct riscv_isainfo *isainfo = &hart_isa[cpu];
 		unsigned long this_hwcap = 0;
+		DECLARE_BITMAP(source_isa, RISCV_ISA_EXT_MAX) = { 0 };
 
 		if (acpi_disabled) {
 			node = of_cpu_device_node_get(cpu);
@@ -527,7 +679,7 @@ static void __init riscv_fill_hwcap_from_isa_string(unsigned long *isa2hwcap)
 			}
 		}
 
-		riscv_parse_isa_string(&this_hwcap, isainfo, isa2hwcap, isa);
+		riscv_parse_isa_string(isa, source_isa);
 
 		/*
 		 * These ones were as they were part of the base ISA when the
@@ -535,10 +687,10 @@ static void __init riscv_fill_hwcap_from_isa_string(unsigned long *isa2hwcap)
 		 * unconditionally where `i` is in riscv,isa on DT systems.
 		 */
 		if (acpi_disabled) {
-			set_bit(RISCV_ISA_EXT_ZICSR, isainfo->isa);
-			set_bit(RISCV_ISA_EXT_ZIFENCEI, isainfo->isa);
-			set_bit(RISCV_ISA_EXT_ZICNTR, isainfo->isa);
-			set_bit(RISCV_ISA_EXT_ZIHPM, isainfo->isa);
+			set_bit(RISCV_ISA_EXT_ZICSR, source_isa);
+			set_bit(RISCV_ISA_EXT_ZIFENCEI, source_isa);
+			set_bit(RISCV_ISA_EXT_ZICNTR, source_isa);
+			set_bit(RISCV_ISA_EXT_ZIHPM, source_isa);
 		}
 
 		/*
@@ -551,9 +703,11 @@ static void __init riscv_fill_hwcap_from_isa_string(unsigned long *isa2hwcap)
 		 */
 		if (acpi_disabled && boot_vendorid == THEAD_VENDOR_ID && boot_archid == 0x0) {
 			this_hwcap &= ~isa2hwcap[RISCV_ISA_EXT_v];
-			clear_bit(RISCV_ISA_EXT_v, isainfo->isa);
+			clear_bit(RISCV_ISA_EXT_v, source_isa);
 		}
 
+		riscv_resolve_isa(source_isa, isainfo->isa, &this_hwcap, isa2hwcap);
+
 		/*
 		 * All "okay" hart should have same isa. Set HWCAP based on
 		 * common capabilities of every "okay" hart, in case they don't
@@ -582,6 +736,7 @@ static int __init riscv_fill_hwcap_from_ext_list(unsigned long *isa2hwcap)
 		unsigned long this_hwcap = 0;
 		struct device_node *cpu_node;
 		struct riscv_isainfo *isainfo = &hart_isa[cpu];
+		DECLARE_BITMAP(source_isa, RISCV_ISA_EXT_MAX) = { 0 };
 
 		cpu_node = of_cpu_device_node_get(cpu);
 		if (!cpu_node) {
@@ -601,22 +756,11 @@ static int __init riscv_fill_hwcap_from_ext_list(unsigned long *isa2hwcap)
 						     ext->property) < 0)
 				continue;
 
-			if (ext->subset_ext_size) {
-				for (int j = 0; j < ext->subset_ext_size; j++) {
-					if (riscv_isa_extension_check(ext->subset_ext_ids[j]))
-						set_bit(ext->subset_ext_ids[j], isainfo->isa);
-				}
-			}
-
-			if (riscv_isa_extension_check(ext->id)) {
-				set_bit(ext->id, isainfo->isa);
-
-				/* Only single letter extensions get set in hwcap */
-				if (strnlen(riscv_isa_ext[i].name, 2) == 1)
-					this_hwcap |= isa2hwcap[riscv_isa_ext[i].id];
-			}
+			riscv_isa_set_ext(ext, source_isa);
 		}
 
+		riscv_resolve_isa(source_isa, isainfo->isa, &this_hwcap, isa2hwcap);
+
 		of_node_put(cpu_node);
 
 		/*
@@ -686,8 +830,14 @@ void __init riscv_fill_hwcap(void)
 		elf_hwcap &= ~COMPAT_HWCAP_ISA_F;
 	}
 
-	if (elf_hwcap & COMPAT_HWCAP_ISA_V) {
+	if (__riscv_isa_extension_available(NULL, RISCV_ISA_EXT_ZVE32X)) {
+		/*
+		 * This cannot fail when called on the boot hart
+		 */
 		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.