diff --git a/Documentation/riscv/uabi.rst b/Documentation/riscv/uabi.rst
index 8960fac42c40f3c7fd288f86f5f8d2233f422f09..54d199dce78bf50525b0430dcfc5a6a71429bf68 100644
--- a/Documentation/riscv/uabi.rst
+++ b/Documentation/riscv/uabi.rst
@@ -42,6 +42,26 @@ An example string following the order is::
 
    rv64imadc_zifoo_zigoo_zafoo_sbar_scar_zxmbaz_xqux_xrux
 
+"isa" and "hart isa" lines in /proc/cpuinfo
+-------------------------------------------
+
+The "isa" line in /proc/cpuinfo describes the lowest common denominator of
+RISC-V ISA extensions recognized by the kernel and implemented on all harts. The
+"hart isa" line, in contrast, describes the set of extensions recognized by the
+kernel on the particular hart being described, even if those extensions may not
+be present on all harts in the system.
+
+In both lines, the presence of an extension guarantees only that the hardware
+has the described capability. Additional kernel support or policy changes may be
+required before an extension's capability is fully usable by userspace programs.
+Similarly, for S-mode extensions, presence in one of these lines does not
+guarantee that the kernel is taking advantage of the extension, or that the
+feature will be visible in guest VMs managed by this kernel.
+
+Inversely, the absence of an extension in these lines does not necessarily mean
+the hardware does not support that feature. The running kernel may not recognize
+the extension, or may have deliberately removed it from the listing.
+
 Misaligned accesses
 -------------------
 
diff --git a/arch/riscv/kernel/cpu.c b/arch/riscv/kernel/cpu.c
index c17dacb1141cb3ca9c077ec8e95c5f39dbc5fabd..bcfc0c8dfd0131b92391ba8fa0f2dcc4864c8954 100644
--- a/arch/riscv/kernel/cpu.c
+++ b/arch/riscv/kernel/cpu.c
@@ -202,9 +202,8 @@ arch_initcall(riscv_cpuinfo_init);
 
 #ifdef CONFIG_PROC_FS
 
-static void print_isa(struct seq_file *f)
+static void print_isa(struct seq_file *f, const unsigned long *isa_bitmap)
 {
-	seq_puts(f, "isa\t\t: ");
 
 	if (IS_ENABLED(CONFIG_32BIT))
 		seq_write(f, "rv32", 4);
@@ -212,7 +211,7 @@ static void print_isa(struct seq_file *f)
 		seq_write(f, "rv64", 4);
 
 	for (int i = 0; i < riscv_isa_ext_count; i++) {
-		if (!__riscv_isa_extension_available(NULL, riscv_isa_ext[i].id))
+		if (!__riscv_isa_extension_available(isa_bitmap, riscv_isa_ext[i].id))
 			continue;
 
 		/* Only multi-letter extensions are split by underscores */
@@ -276,7 +275,15 @@ static int c_show(struct seq_file *m, void *v)
 
 	seq_printf(m, "processor\t: %lu\n", cpu_id);
 	seq_printf(m, "hart\t\t: %lu\n", cpuid_to_hartid_map(cpu_id));
-	print_isa(m);
+
+	/*
+	 * For historical raisins, the isa: line is limited to the lowest common
+	 * denominator of extensions supported across all harts. A true list of
+	 * extensions supported on this hart is printed later in the hart isa:
+	 * line.
+	 */
+	seq_puts(m, "isa\t\t: ");
+	print_isa(m, NULL);
 	print_mmu(m);
 
 	if (acpi_disabled) {
@@ -292,6 +299,13 @@ static int c_show(struct seq_file *m, void *v)
 	seq_printf(m, "mvendorid\t: 0x%lx\n", ci->mvendorid);
 	seq_printf(m, "marchid\t\t: 0x%lx\n", ci->marchid);
 	seq_printf(m, "mimpid\t\t: 0x%lx\n", ci->mimpid);
+
+	/*
+	 * Print the ISA extensions specific to this hart, which may show
+	 * additional extensions not present across all harts.
+	 */
+	seq_puts(m, "hart isa\t: ");
+	print_isa(m, hart_isa[cpu_id].isa);
 	seq_puts(m, "\n");
 
 	return 0;