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-rw-r--r--arch/riscv/include/asm/hwcap.h7
-rw-r--r--arch/riscv/kernel/cpu.c65
2 files changed, 70 insertions, 2 deletions
diff --git a/arch/riscv/include/asm/hwcap.h b/arch/riscv/include/asm/hwcap.h
index 170bd80da520..691fc9c8099b 100644
--- a/arch/riscv/include/asm/hwcap.h
+++ b/arch/riscv/include/asm/hwcap.h
@@ -54,6 +54,13 @@ enum riscv_isa_ext_id {
RISCV_ISA_EXT_ID_MAX = RISCV_ISA_EXT_MAX,
};
+struct riscv_isa_ext_data {
+ /* Name of the extension displayed to userspace via /proc/cpuinfo */
+ char uprop[RISCV_ISA_EXT_NAME_LEN_MAX];
+ /* The logical ISA extension ID */
+ unsigned int isa_ext_id;
+};
+
unsigned long riscv_isa_extension_base(const unsigned long *isa_bitmap);
#define riscv_isa_extension_mask(ext) BIT_MASK(RISCV_ISA_EXT_##ext)
diff --git a/arch/riscv/kernel/cpu.c b/arch/riscv/kernel/cpu.c
index ad0a7e9f828b..fc115e307ef5 100644
--- a/arch/riscv/kernel/cpu.c
+++ b/arch/riscv/kernel/cpu.c
@@ -6,6 +6,7 @@
#include <linux/init.h>
#include <linux/seq_file.h>
#include <linux/of.h>
+#include <asm/hwcap.h>
#include <asm/smp.h>
#include <asm/pgtable.h>
@@ -63,12 +64,72 @@ int riscv_of_parent_hartid(struct device_node *node)
}
#ifdef CONFIG_PROC_FS
+#define __RISCV_ISA_EXT_DATA(UPROP, EXTID) \
+ { \
+ .uprop = #UPROP, \
+ .isa_ext_id = EXTID, \
+ }
+/**
+ * Here are the ordering rules of extension naming defined by RISC-V
+ * specification :
+ * 1. All extensions should be separated from other multi-letter extensions
+ * from other multi-letter extensions by an underscore.
+ * 2. The first letter following the 'Z' conventionally indicates the most
+ * closely related alphabetical extension category, IMAFDQLCBKJTPVH.
+ * If multiple 'Z' extensions are named, they should be ordered first
+ * by category, then alphabetically within a category.
+ * 3. Standard supervisor-level extensions (starts with 'S') should be
+ * listed after standard unprivileged extensions. If multiple
+ * supervisor-level extensions are listed, they should be ordered
+ * alphabetically.
+ * 4. Non-standard extensions (starts with 'X') must be listed after all
+ * standard extensions. They must be separated from other multi-letter
+ * extensions by an underscore.
+ */
+static struct riscv_isa_ext_data isa_ext_arr[] = {
+ __RISCV_ISA_EXT_DATA("", RISCV_ISA_EXT_MAX),
+};
+
+static void print_isa_ext(struct seq_file *f)
+{
+ struct riscv_isa_ext_data *edata;
+ int i = 0, arr_sz;
+
+ arr_sz = ARRAY_SIZE(isa_ext_arr) - 1;
+
+ /* No extension support available */
+ if (arr_sz <= 0)
+ return;
+
+ for (i = 0; i <= arr_sz; i++) {
+ edata = &isa_ext_arr[i];
+ if (!__riscv_isa_extension_available(NULL, edata->isa_ext_id))
+ continue;
+ seq_printf(f, "_%s", edata->uprop);
+ }
+}
+
+/**
+ * These are the only valid base (single letter) ISA extensions as per the spec.
+ * It also specifies the canonical order in which it appears in the spec.
+ * Some of the extension may just be a place holder for now (B, K, P, J).
+ * This should be updated once corresponding extensions are ratified.
+ */
+static const char base_riscv_exts[13] = "imafdqcbkjpvh";
static void print_isa(struct seq_file *f, const char *isa)
{
- /* Print the entire ISA as it is */
+ int i;
+
seq_puts(f, "isa\t\t: ");
- seq_write(f, isa, strlen(isa));
+ /* Print the rv[64/32] part */
+ seq_write(f, isa, 4);
+ for (i = 0; i < sizeof(base_riscv_exts); i++) {
+ if (__riscv_isa_extension_available(NULL, base_riscv_exts[i] - 'a'))
+ /* Print only enabled the base ISA extensions */
+ seq_write(f, &base_riscv_exts[i], 1);
+ }
+ print_isa_ext(f);
seq_puts(f, "\n");
}