riscv: Add vendor extensions to /proc/cpuinfo

All of the supported vendor extensions that have been listed in
riscv_isa_vendor_ext_list can be exported through /proc/cpuinfo.
Signed-off-by: Charlie Jenkins <charlie@rivosinc.com>
Reviewed-by: Evan Green <evan@rivosinc.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20240719-support_vendor_extensions-v3-2-0af7587bbec0@rivosinc.comSigned-off-by: Palmer Dabbelt <palmer@rivosinc.com>

arch/riscv/kernel/cpu.c

@@ -16,6 +16,7 @@
 #include <asm/sbi.h>
 #include <asm/smp.h>
 #include <asm/pgtable.h>
+#include <asm/vendor_extensions.h>
 
 bool arch_match_cpu_phys_id(int cpu, u64 phys_id)
 {
@@ -235,7 +236,33 @@ arch_initcall(riscv_cpuinfo_init);
 
 #ifdef CONFIG_PROC_FS
 
-static void print_isa(struct seq_file *f, const unsigned long *isa_bitmap)
+#define ALL_CPUS -1
+
+static void print_vendor_isa(struct seq_file *f, int cpu)
+{
+	struct riscv_isavendorinfo *vendor_bitmap;
+	struct riscv_isa_vendor_ext_data_list *ext_list;
+	const struct riscv_isa_ext_data *ext_data;
+
+	for (int i = 0; i < riscv_isa_vendor_ext_list_size; i++) {
+		ext_list = riscv_isa_vendor_ext_list[i];
+		ext_data = riscv_isa_vendor_ext_list[i]->ext_data;
+
+		if (cpu == ALL_CPUS)
+			vendor_bitmap = &ext_list->all_harts_isa_bitmap;
+		else
+			vendor_bitmap = &ext_list->per_hart_isa_bitmap[cpu];
+
+		for (int j = 0; j < ext_list->ext_data_count; j++) {
+			if (!__riscv_isa_extension_available(vendor_bitmap->isa, ext_data[j].id))
+				continue;
+
+			seq_printf(f, "_%s", ext_data[j].name);
+		}
+	}
+}
+
+static void print_isa(struct seq_file *f, const unsigned long *isa_bitmap, int cpu)
 {
 
 	if (IS_ENABLED(CONFIG_32BIT))
@@ -254,6 +281,8 @@ static void print_isa(struct seq_file *f, const unsigned long *isa_bitmap)
 		seq_printf(f, "%s", riscv_isa_ext[i].name);
 	}
 
+	print_vendor_isa(f, cpu);
+
 	seq_puts(f, "\n");
 }
 
@@ -316,7 +345,7 @@ static int c_show(struct seq_file *m, void *v)
 	 * line.
 	 */
 	seq_puts(m, "isa\t\t: ");
-	print_isa(m, NULL);
+	print_isa(m, NULL, ALL_CPUS);
 	print_mmu(m);
 
 	if (acpi_disabled) {
@@ -338,7 +367,7 @@ static int c_show(struct seq_file *m, void *v)
 	 * additional extensions not present across all harts.
 	 */
 	seq_puts(m, "hart isa\t: ");
-	print_isa(m, hart_isa[cpu_id].isa);
+	print_isa(m, hart_isa[cpu_id].isa, cpu_id);
 	seq_puts(m, "\n");
 
 	return 0;