diff --git a/arch/riscv/errata/sifive/errata.c b/arch/riscv/errata/sifive/errata.c
index 3d9a32d791f7..b29b6e405ff2 100644
--- a/arch/riscv/errata/sifive/errata.c
+++ b/arch/riscv/errata/sifive/errata.c
@@ -12,6 +12,7 @@
 #include <asm/alternative.h>
 #include <asm/vendorid_list.h>
 #include <asm/errata_list.h>
+#include <asm/vendor_extensions.h>
 
 struct errata_info_t {
 	char name[32];
@@ -99,6 +100,8 @@ void sifive_errata_patch_func(struct alt_entry *begin, struct alt_entry *end,
 	for (alt = begin; alt < end; alt++) {
 		if (alt->vendor_id != SIFIVE_VENDOR_ID)
 			continue;
+		if (alt->patch_id >= RISCV_VENDOR_EXT_ALTERNATIVES_BASE)
+			continue;
 		if (alt->patch_id >= ERRATA_SIFIVE_NUMBER) {
 			WARN(1, "This errata id:%d is not in kernel errata list", alt->patch_id);
 			continue;
diff --git a/arch/riscv/errata/thead/errata.c b/arch/riscv/errata/thead/errata.c
index b1c410bbc1ae..d8e78cc687bc 100644
--- a/arch/riscv/errata/thead/errata.c
+++ b/arch/riscv/errata/thead/errata.c
@@ -18,6 +18,7 @@
 #include <asm/io.h>
 #include <asm/patch.h>
 #include <asm/vendorid_list.h>
+#include <asm/vendor_extensions.h>
 
 static bool errata_probe_pbmt(unsigned int stage,
 			      unsigned long arch_id, unsigned long impid)
@@ -163,6 +164,8 @@ void thead_errata_patch_func(struct alt_entry *begin, struct alt_entry *end,
 	for (alt = begin; alt < end; alt++) {
 		if (alt->vendor_id != THEAD_VENDOR_ID)
 			continue;
+		if (alt->patch_id >= RISCV_VENDOR_EXT_ALTERNATIVES_BASE)
+			continue;
 		if (alt->patch_id >= ERRATA_THEAD_NUMBER)
 			continue;
 
diff --git a/arch/riscv/include/asm/cpufeature.h b/arch/riscv/include/asm/cpufeature.h
index db6a6d7d6b2e..83e1143db9ad 100644
--- a/arch/riscv/include/asm/cpufeature.h
+++ b/arch/riscv/include/asm/cpufeature.h
@@ -103,22 +103,13 @@ bool __riscv_isa_extension_available(const unsigned long *isa_bitmap, unsigned i
 	__riscv_isa_extension_available(isa_bitmap, RISCV_ISA_EXT_##ext)
 
 static __always_inline bool
-riscv_has_extension_likely(const unsigned long ext)
+__riscv_has_extension_likely_alternatives(const unsigned long vendor, const unsigned long ext)
 {
-	compiletime_assert(ext < RISCV_ISA_EXT_MAX,
-			   "ext must be < RISCV_ISA_EXT_MAX");
-
-	if (IS_ENABLED(CONFIG_RISCV_ALTERNATIVE)) {
-		asm goto(
-		ALTERNATIVE("j	%l[l_no]", "nop", 0, %[ext], 1)
-		:
-		: [ext] "i" (ext)
-		:
-		: l_no);
-	} else {
-		if (!__riscv_isa_extension_available(NULL, ext))
-			goto l_no;
-	}
+	asm goto(ALTERNATIVE("j	%l[l_no]", "nop", %[vendor], %[ext], 1)
+	:
+	: [vendor] "i" (vendor), [ext] "i" (ext)
+	:
+	: l_no);
 
 	return true;
 l_no:
@@ -126,42 +117,65 @@ riscv_has_extension_likely(const unsigned long ext)
 }
 
 static __always_inline bool
-riscv_has_extension_unlikely(const unsigned long ext)
+__riscv_has_extension_unlikely_alternatives(const unsigned long vendor, const unsigned long ext)
 {
-	compiletime_assert(ext < RISCV_ISA_EXT_MAX,
-			   "ext must be < RISCV_ISA_EXT_MAX");
-
-	if (IS_ENABLED(CONFIG_RISCV_ALTERNATIVE)) {
-		asm goto(
-		ALTERNATIVE("nop", "j	%l[l_yes]", 0, %[ext], 1)
-		:
-		: [ext] "i" (ext)
-		:
-		: l_yes);
-	} else {
-		if (__riscv_isa_extension_available(NULL, ext))
-			goto l_yes;
-	}
+	asm goto(ALTERNATIVE("nop", "j	%l[l_yes]", %[vendor], %[ext], 1)
+	:
+	: [vendor] "i" (vendor), [ext] "i" (ext)
+	:
+	: l_yes);
 
 	return false;
 l_yes:
 	return true;
 }
 
+static __always_inline bool
+riscv_has_extension_likely(const unsigned long ext)
+{
+	compiletime_assert(ext < RISCV_ISA_EXT_MAX,
+			   "ext must be < RISCV_ISA_EXT_MAX");
+
+	if (IS_ENABLED(CONFIG_RISCV_ALTERNATIVE))
+		return __riscv_has_extension_likely_alternatives(0, ext);
+	else
+		return __riscv_isa_extension_available(NULL, ext);
+}
+
+static __always_inline bool
+riscv_has_extension_unlikely(const unsigned long ext)
+{
+	compiletime_assert(ext < RISCV_ISA_EXT_MAX,
+			   "ext must be < RISCV_ISA_EXT_MAX");
+
+	if (IS_ENABLED(CONFIG_RISCV_ALTERNATIVE))
+		return __riscv_has_extension_unlikely_alternatives(0, ext);
+	else
+		return __riscv_isa_extension_available(NULL, ext);
+}
+
 static __always_inline bool riscv_cpu_has_extension_likely(int cpu, const unsigned long ext)
 {
-	if (IS_ENABLED(CONFIG_RISCV_ALTERNATIVE) && riscv_has_extension_likely(ext))
-		return true;
+	compiletime_assert(ext < RISCV_ISA_EXT_MAX,
+			   "ext must be < RISCV_ISA_EXT_MAX");
 
-	return __riscv_isa_extension_available(hart_isa[cpu].isa, ext);
+	if (IS_ENABLED(CONFIG_RISCV_ALTERNATIVE) &&
+	    __riscv_has_extension_likely_alternatives(0, ext))
+		return true;
+	else
+		return __riscv_isa_extension_available(hart_isa[cpu].isa, ext);
 }
 
 static __always_inline bool riscv_cpu_has_extension_unlikely(int cpu, const unsigned long ext)
 {
-	if (IS_ENABLED(CONFIG_RISCV_ALTERNATIVE) && riscv_has_extension_unlikely(ext))
-		return true;
+	compiletime_assert(ext < RISCV_ISA_EXT_MAX,
+			   "ext must be < RISCV_ISA_EXT_MAX");
 
-	return __riscv_isa_extension_available(hart_isa[cpu].isa, ext);
+	if (IS_ENABLED(CONFIG_RISCV_ALTERNATIVE) &&
+	    __riscv_has_extension_unlikely_alternatives(0, ext))
+		return true;
+	else
+		return __riscv_isa_extension_available(hart_isa[cpu].isa, ext);
 }
 
 #endif
diff --git a/arch/riscv/include/asm/vendor_extensions.h b/arch/riscv/include/asm/vendor_extensions.h
index 0af1ddd0af70..3e676a96016e 100644
--- a/arch/riscv/include/asm/vendor_extensions.h
+++ b/arch/riscv/include/asm/vendor_extensions.h
@@ -23,4 +23,60 @@ extern const struct riscv_isa_vendor_ext_data_list *riscv_isa_vendor_ext_list[];
 
 extern const size_t riscv_isa_vendor_ext_list_size;
 
+/*
+ * The alternatives need some way of distinguishing between vendor extensions
+ * and errata. Incrementing all of the vendor extension keys so they are at
+ * least 0x8000 accomplishes that.
+ */
+#define RISCV_VENDOR_EXT_ALTERNATIVES_BASE	0x8000
+
+bool __riscv_isa_vendor_extension_available(int cpu, unsigned long vendor, unsigned int bit);
+#define riscv_cpu_isa_vendor_extension_available(cpu, vendor, ext)	\
+	__riscv_isa_vendor_extension_available(cpu, vendor, RISCV_ISA_VENDOR_EXT_##ext)
+#define riscv_isa_vendor_extension_available(vendor, ext)	\
+	__riscv_isa_vendor_extension_available(-1, vendor, RISCV_ISA_VENDOR_EXT_##ext)
+
+static __always_inline bool
+riscv_has_vendor_extension_likely(const unsigned long vendor, const unsigned long ext)
+{
+	if (IS_ENABLED(CONFIG_RISCV_ALTERNATIVE))
+		return __riscv_has_extension_likely_alternatives(vendor,
+								 ext + RISCV_VENDOR_EXT_ALTERNATIVES_BASE);
+	else
+		return __riscv_isa_vendor_extension_available(-1, vendor, ext);
+}
+
+static __always_inline bool
+riscv_has_vendor_extension_unlikely(const unsigned long vendor, const unsigned long ext)
+{
+	if (IS_ENABLED(CONFIG_RISCV_ALTERNATIVE))
+		return __riscv_has_extension_unlikely_alternatives(vendor,
+								   ext + RISCV_VENDOR_EXT_ALTERNATIVES_BASE);
+	else
+		return __riscv_isa_vendor_extension_available(-1, vendor, ext);
+}
+
+static __always_inline bool riscv_cpu_has_vendor_extension_likely(const unsigned long vendor,
+								  int cpu, const unsigned long ext)
+{
+	if (IS_ENABLED(CONFIG_RISCV_ALTERNATIVE) &&
+	    __riscv_has_extension_likely_alternatives(vendor,
+						      ext + RISCV_VENDOR_EXT_ALTERNATIVES_BASE))
+		return true;
+	else
+		return __riscv_isa_vendor_extension_available(cpu, vendor, ext);
+}
+
+static __always_inline bool riscv_cpu_has_vendor_extension_unlikely(const unsigned long vendor,
+								    int cpu,
+								    const unsigned long ext)
+{
+	if (IS_ENABLED(CONFIG_RISCV_ALTERNATIVE) &&
+	    __riscv_has_extension_unlikely_alternatives(vendor,
+							ext + RISCV_VENDOR_EXT_ALTERNATIVES_BASE))
+		return true;
+	else
+		return __riscv_isa_vendor_extension_available(cpu, vendor, ext);
+}
+
 #endif /* _ASM_VENDOR_EXTENSIONS_H */
diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
index c9f36822e337..17371887abcc 100644
--- a/arch/riscv/kernel/cpufeature.c
+++ b/arch/riscv/kernel/cpufeature.c
@@ -833,25 +833,29 @@ void __init_or_module riscv_cpufeature_patch_func(struct alt_entry *begin,
 {
 	struct alt_entry *alt;
 	void *oldptr, *altptr;
-	u16 id, value;
+	u16 id, value, vendor;
 
 	if (stage == RISCV_ALTERNATIVES_EARLY_BOOT)
 		return;
 
 	for (alt = begin; alt < end; alt++) {
-		if (alt->vendor_id != 0)
-			continue;
-
 		id = PATCH_ID_CPUFEATURE_ID(alt->patch_id);
+		vendor = PATCH_ID_CPUFEATURE_ID(alt->vendor_id);
 
-		if (id >= RISCV_ISA_EXT_MAX) {
+		if (id < RISCV_ISA_EXT_MAX) {
+			if (alt->vendor_id != 0)
+				continue;
+
+			if (!__riscv_isa_extension_available(NULL, id))
+				continue;
+		} else if (id >= RISCV_VENDOR_EXT_ALTERNATIVES_BASE) {
+			if (!__riscv_isa_vendor_extension_available(-1, vendor, id))
+				continue;
+		} else {
 			WARN(1, "This extension id:%d is not in ISA extension list", id);
 			continue;
 		}
 
-		if (!__riscv_isa_extension_available(NULL, id))
-			continue;
-
 		value = PATCH_ID_CPUFEATURE_VALUE(alt->patch_id);
 		if (!riscv_cpufeature_patch_check(id, value))
 			continue;
diff --git a/arch/riscv/kernel/vendor_extensions.c b/arch/riscv/kernel/vendor_extensions.c
index f76cb3013c2d..eced93eec5a6 100644
--- a/arch/riscv/kernel/vendor_extensions.c
+++ b/arch/riscv/kernel/vendor_extensions.c
@@ -3,6 +3,7 @@
  * Copyright 2024 Rivos, Inc
  */
 
+#include <asm/vendorid_list.h>
 #include <asm/vendor_extensions.h>
 #include <asm/vendor_extensions/thead.h>
 
@@ -16,3 +17,42 @@ const struct riscv_isa_vendor_ext_data_list *riscv_isa_vendor_ext_list[] = {
 };
 
 const size_t riscv_isa_vendor_ext_list_size = ARRAY_SIZE(riscv_isa_vendor_ext_list);
+
+/**
+ * __riscv_isa_vendor_extension_available() - Check whether given vendor
+ * extension is available or not.
+ *
+ * @cpu: check if extension is available on this cpu
+ * @vendor: vendor that the extension is a member of
+ * @bit: bit position of the desired extension
+ * Return: true or false
+ *
+ * NOTE: When cpu is -1, will check if extension is available on all cpus
+ */
+bool __riscv_isa_vendor_extension_available(int cpu, unsigned long vendor, unsigned int bit)
+{
+	unsigned long *bmap;
+	struct riscv_isainfo *cpu_bmap;
+	size_t bmap_size;
+
+	switch (vendor) {
+#ifdef CONFIG_RISCV_ISA_VENDOR_EXT_THEAD
+	case THEAD_VENDOR_ID:
+		bmap = riscv_isa_vendor_ext_list_thead.vendor_bitmap;
+		cpu_bmap = riscv_isa_vendor_ext_list_thead.per_hart_vendor_bitmap;
+		bmap_size = riscv_isa_vendor_ext_list_thead.bitmap_size;
+		break;
+#endif
+	default:
+		return false;
+	}
+
+	if (cpu != -1)
+		bmap = cpu_bmap[cpu].isa;
+
+	if (bit >= bmap_size)
+		return false;
+
+	return test_bit(bit, bmap) ? true : false;
+}
+EXPORT_SYMBOL_GPL(__riscv_isa_vendor_extension_available);
