[PATCH v1 1/2] riscv: Enhance extension probing

Mayuresh Chitale
2025-01-06T13:04:37Z

Enhance the existing extension probing mechanism by adding support for
more extensions and probing using the "riscv,isa" property. This patch
is ported from the latest upstream linux.

Signed-off-by: Mayuresh Chitale <mchitale@ventanamicro.com>
---
arch/riscv/cpu/cpu.c | 557 ++++++++++++++++++++++++++++
arch/riscv/include/asm/cpufeature.h | 37 ++
arch/riscv/include/asm/hwcap.h | 105 ++++++
3 files changed, 699 insertions(+)
create mode 100644 arch/riscv/include/asm/cpufeature.h
create mode 100644 arch/riscv/include/asm/hwcap.h

diff --git a/arch/riscv/cpu/cpu.c b/arch/riscv/cpu/cpu.c
index affe70081b5..f3f9f9f2351 100644
--- a/arch/riscv/cpu/cpu.c
+++ b/arch/riscv/cpu/cpu.c
@@ -14,8 +14,12 @@
#include <log.h>
#include <asm/encoding.h>
#include <asm/system.h>
+#include <asm/hwcap.h>
+#include <asm/cpufeature.h>
#include <dm/uclass-internal.h>
#include <linux/bitops.h>
+#include <linux/log2.h>
+#include <linux/ctype.h>

/*
* The variables here must be stored in the data section since they are used
@@ -33,6 +37,559 @@ u32 available_harts_lock = 1;
#endif
#endif

+/* Host ISA bitmap */
+static DECLARE_BITMAP(riscv_isa, RISCV_ISA_EXT_MAX) __section(".data");
+
+static unsigned int riscv_cbom_block_size __section(".data");
+static unsigned int riscv_cboz_block_size __section(".data");
+/**
+ * __riscv_isa_extension_available() - Check whether given extension
+ * is available or not
+ *
+ * @bit: bit position of the desired extension
+ * Return: true or false
+ *
+ */
+static bool __riscv_isa_extension_available(unsigned int bit)
+{
+ if (bit >= RISCV_ISA_EXT_MAX)
+ return false;
+
+ return test_bit(bit, riscv_isa) ? true : false;
+}
+
+inline unsigned int riscv_get_cbom_block_size(void)
+{
+ return riscv_cbom_block_size;
+}
+
+inline unsigned int riscv_get_cboz_block_size(void)
+{
+ return riscv_cboz_block_size;
+}
+
+static int riscv_ext_zicbom_validate(const struct riscv_isa_ext_data *data,
+ const unsigned long *isa_bitmap)
+{
+ struct udevice *dev;
+
+ if (!CONFIG_IS_ENABLED(RISCV_ISA_ZICBOM) || riscv_cbom_block_size)
+ return 0;
+
+ uclass_first_device(UCLASS_CPU, &dev);
+ if (!dev) {
+ log_info("Failed to get cpu device!\n");
+ return -ENXIO;
+ }
+
+ if (!dev_read_u32(dev, "riscv,cbom-block-size",
+ &riscv_cbom_block_size)) {
+ if (!riscv_cbom_block_size) {
+ log_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)) {
+ log_err("Zicbom disabled as cbom-block-size present, but is not a power-of-2\n");
+ return -EINVAL;
+ }
+ return 0;
+ } else {
+ return -EINVAL;
+ }
+}
+
+static int riscv_ext_zicboz_validate(const struct riscv_isa_ext_data *data,
+ const unsigned long *isa_bitmap)
+{
+ struct udevice *dev;
+
+ if (!CONFIG_IS_ENABLED(RISCV_ISA_ZICBOM) || riscv_cboz_block_size)
+ return 0;
+
+ uclass_first_device(UCLASS_CPU, &dev);
+ if (!dev) {
+ log_debug("Failed to get cpu device!\n");
+ return -ENXIO;
+ }
+
+ if (!dev_read_u32(dev, "riscv,cboz-block-size",
+ &riscv_cboz_block_size)) {
+ if (!riscv_cboz_block_size) {
+ log_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)) {
+ log_err("Zicboz disabled as cboz-block-size present, but is not a power-of-2\n");
+ return -EINVAL;
+ }
+ return 0;
+ } else {
+ return -EINVAL;
+ }
+}
+
+static int riscv_ext_zca_depends(const struct riscv_isa_ext_data *data,
+ const unsigned long *isa_bitmap)
+{
+ if (__riscv_isa_extension_available(RISCV_ISA_EXT_ZCA))
+ return 0;
+
+ return -EINVAL;
+}
+
+static int riscv_ext_zcd_validate(const struct riscv_isa_ext_data *data,
+ const unsigned long *isa_bitmap)
+{
+ if (__riscv_isa_extension_available(RISCV_ISA_EXT_ZCA) &&
+ __riscv_isa_extension_available(RISCV_ISA_EXT_d))
+ return 0;
+
+ return -EINVAL;
+}
+
+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(RISCV_ISA_EXT_ZCA) &&
+ __riscv_isa_extension_available(RISCV_ISA_EXT_f))
+ return 0;
+
+ return -EINVAL;
+}
+
+static const unsigned int riscv_zk_bundled_exts[] = {
+ RISCV_ISA_EXT_ZBKB,
+ RISCV_ISA_EXT_ZBKC,
+ RISCV_ISA_EXT_ZBKX,
+ RISCV_ISA_EXT_ZKND,
+ RISCV_ISA_EXT_ZKNE,
+ RISCV_ISA_EXT_ZKR,
+ RISCV_ISA_EXT_ZKT,
+};
+
+static const unsigned int riscv_zkn_bundled_exts[] = {
+ RISCV_ISA_EXT_ZBKB,
+ RISCV_ISA_EXT_ZBKC,
+ RISCV_ISA_EXT_ZBKX,
+ RISCV_ISA_EXT_ZKND,
+ RISCV_ISA_EXT_ZKNE,
+ RISCV_ISA_EXT_ZKNH,
+};
+
+static const unsigned int riscv_zks_bundled_exts[] = {
+ RISCV_ISA_EXT_ZBKB,
+ RISCV_ISA_EXT_ZBKC,
+ RISCV_ISA_EXT_ZKSED,
+ RISCV_ISA_EXT_ZKSH
+};
+
+#define RISCV_ISA_EXT_ZVKN \
+ RISCV_ISA_EXT_ZVKNED, \
+ RISCV_ISA_EXT_ZVKNHB, \
+ RISCV_ISA_EXT_ZVKB, \
+ RISCV_ISA_EXT_ZVKT
+
+static const unsigned int riscv_zvkn_bundled_exts[] = {
+ RISCV_ISA_EXT_ZVKN
+};
+
+static const unsigned int riscv_zvknc_bundled_exts[] = {
+ RISCV_ISA_EXT_ZVKN,
+ RISCV_ISA_EXT_ZVBC
+};
+
+static const unsigned int riscv_zvkng_bundled_exts[] = {
+ RISCV_ISA_EXT_ZVKN,
+ RISCV_ISA_EXT_ZVKG
+};
+
+#define RISCV_ISA_EXT_ZVKS \
+ RISCV_ISA_EXT_ZVKSED, \
+ RISCV_ISA_EXT_ZVKSH, \
+ RISCV_ISA_EXT_ZVKB, \
+ RISCV_ISA_EXT_ZVKT
+
+static const unsigned int riscv_zvks_bundled_exts[] = {
+ RISCV_ISA_EXT_ZVKS
+};
+
+static const unsigned int riscv_zvksc_bundled_exts[] = {
+ RISCV_ISA_EXT_ZVKS,
+ RISCV_ISA_EXT_ZVBC
+};
+
+static const unsigned int riscv_zvksg_bundled_exts[] = {
+ RISCV_ISA_EXT_ZVKS,
+ RISCV_ISA_EXT_ZVKG
+};
+
+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
+ * specifies [ms]envcfg bit(s). Hence, we define a custom ISA extension for the
+ * existence of the CSR, and treat it as a subset of those other extensions.
+ */
+static const unsigned int riscv_xlinuxenvcfg_exts[] = {
+ RISCV_ISA_EXT_XLINUXENVCFG
+};
+
+/*
+ * 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.
+ *
+ * Ordinarily, for in-kernel data structures, this order is unimportant but
+ * isa_ext_arr defines the order of the ISA string in /proc/cpuinfo.
+ *
+ * The specification uses vague wording, such as should, when it comes to
+ * ordering, so for our purposes the following rules apply:
+ *
+ * 1. All multi-letter extensions must be separated from other extensions by an
+ * underscore.
+ *
+ * 2. Additional standard extensions (starting with 'Z') must be sorted after
+ * single-letter extensions and before any higher-privileged extensions.
+ *
+ * 3. The first letter following the 'Z' conventionally indicates the most
+ * closely related alphabetical extension category, IMAFDQLCBKJTPVH.
+ * If multiple 'Z' extensions are named, they must be ordered first by
+ * category, then alphabetically within a category.
+ *
+ * 3. Standard supervisor-level extensions (starting with 'S') must be listed
+ * after standard unprivileged extensions. If multiple supervisor-level
+ * extensions are listed, they must be ordered alphabetically.
+ *
+ * 4. Standard machine-level extensions (starting with 'Zxm') must be listed
+ * after any lower-privileged, standard extensions. If multiple
+ * machine-level extensions are listed, they must be ordered
+ * alphabetically.
+ *
+ * 5. Non-standard extensions (starting with 'X') must be listed after all
+ * standard extensions. If multiple non-standard extensions are listed, they
+ * must be ordered alphabetically.
+ *
+ * An example string following the order is:
+ * rv64imadc_zifoo_zigoo_zafoo_sbar_scar_zxmbaz_xqux_xrux
+ *
+ * New entries to this struct should follow the ordering rules described above.
+ */
+const struct riscv_isa_ext_data riscv_isa_ext[] = {
+ __RISCV_ISA_EXT_DATA(i, RISCV_ISA_EXT_i),
+ __RISCV_ISA_EXT_DATA(m, RISCV_ISA_EXT_m),
+ __RISCV_ISA_EXT_DATA(a, RISCV_ISA_EXT_a),
+ __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_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_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),
+ __RISCV_ISA_EXT_DATA(zifencei, RISCV_ISA_EXT_ZIFENCEI),
+ __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),
+ __RISCV_ISA_EXT_DATA(zbkb, RISCV_ISA_EXT_ZBKB),
+ __RISCV_ISA_EXT_DATA(zbkc, RISCV_ISA_EXT_ZBKC),
+ __RISCV_ISA_EXT_DATA(zbkx, RISCV_ISA_EXT_ZBKX),
+ __RISCV_ISA_EXT_DATA(zbs, RISCV_ISA_EXT_ZBS),
+ __RISCV_ISA_EXT_BUNDLE(zk, riscv_zk_bundled_exts),
+ __RISCV_ISA_EXT_BUNDLE(zkn, riscv_zkn_bundled_exts),
+ __RISCV_ISA_EXT_DATA(zknd, RISCV_ISA_EXT_ZKND),
+ __RISCV_ISA_EXT_DATA(zkne, RISCV_ISA_EXT_ZKNE),
+ __RISCV_ISA_EXT_DATA(zknh, RISCV_ISA_EXT_ZKNH),
+ __RISCV_ISA_EXT_DATA(zkr, RISCV_ISA_EXT_ZKR),
+ __RISCV_ISA_EXT_BUNDLE(zks, riscv_zks_bundled_exts),
+ __RISCV_ISA_EXT_DATA(zkt, RISCV_ISA_EXT_ZKT),
+ __RISCV_ISA_EXT_DATA(zksed, RISCV_ISA_EXT_ZKSED),
+ __RISCV_ISA_EXT_DATA(zksh, RISCV_ISA_EXT_ZKSH),
+ __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),
+ __RISCV_ISA_EXT_DATA(zvkg, RISCV_ISA_EXT_ZVKG),
+ __RISCV_ISA_EXT_BUNDLE(zvkn, riscv_zvkn_bundled_exts),
+ __RISCV_ISA_EXT_BUNDLE(zvknc, riscv_zvknc_bundled_exts),
+ __RISCV_ISA_EXT_DATA(zvkned, RISCV_ISA_EXT_ZVKNED),
+ __RISCV_ISA_EXT_BUNDLE(zvkng, riscv_zvkng_bundled_exts),
+ __RISCV_ISA_EXT_DATA(zvknha, RISCV_ISA_EXT_ZVKNHA),
+ __RISCV_ISA_EXT_DATA(zvknhb, RISCV_ISA_EXT_ZVKNHB),
+ __RISCV_ISA_EXT_BUNDLE(zvks, riscv_zvks_bundled_exts),
+ __RISCV_ISA_EXT_BUNDLE(zvksc, riscv_zvksc_bundled_exts),
+ __RISCV_ISA_EXT_DATA(zvksed, RISCV_ISA_EXT_ZVKSED),
+ __RISCV_ISA_EXT_DATA(zvksh, RISCV_ISA_EXT_ZVKSH),
+ __RISCV_ISA_EXT_BUNDLE(zvksg, riscv_zvksg_bundled_exts),
+ __RISCV_ISA_EXT_DATA(zvkt, RISCV_ISA_EXT_ZVKT),
+ __RISCV_ISA_EXT_DATA(smaia, RISCV_ISA_EXT_SMAIA),
+ __RISCV_ISA_EXT_DATA(smmpm, RISCV_ISA_EXT_SMMPM),
+ __RISCV_ISA_EXT_SUPERSET(smnpm, RISCV_ISA_EXT_SMNPM, riscv_xlinuxenvcfg_exts),
+ __RISCV_ISA_EXT_DATA(smstateen, RISCV_ISA_EXT_SMSTATEEN),
+ __RISCV_ISA_EXT_DATA(ssaia, RISCV_ISA_EXT_SSAIA),
+ __RISCV_ISA_EXT_DATA(sscofpmf, RISCV_ISA_EXT_SSCOFPMF),
+ __RISCV_ISA_EXT_SUPERSET(ssnpm, RISCV_ISA_EXT_SSNPM, riscv_xlinuxenvcfg_exts),
+ __RISCV_ISA_EXT_DATA(sstc, RISCV_ISA_EXT_SSTC),
+ __RISCV_ISA_EXT_DATA(svinval, RISCV_ISA_EXT_SVINVAL),
+ __RISCV_ISA_EXT_DATA(svnapot, RISCV_ISA_EXT_SVNAPOT),
+ __RISCV_ISA_EXT_DATA(svpbmt, RISCV_ISA_EXT_SVPBMT),
+ __RISCV_ISA_EXT_DATA(svvptc, RISCV_ISA_EXT_SVVPTC),
+};
+
+const size_t riscv_isa_ext_count = ARRAY_SIZE(riscv_isa_ext);
+
+static void riscv_isa_set_ext(const struct riscv_isa_ext_data *ext, unsigned long *bitmap)
+{
+ 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 void match_isa_ext(const char *name, const char *name_end)
+{
+ 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)) {
+ if (ext->validate && !ext->validate(ext, riscv_isa))
+ riscv_isa_set_ext(ext, riscv_isa);
+ break;
+ }
+ }
+}
+
+static void riscv_parse_isa_string(const char *isa)
+{
+ /*
+ * For all possible cpus, we have already validated in
+ * the boot process that they at least contain "rv" and
+ * whichever of "32"/"64" this kernel supports, and so this
+ * section can be skipped.
+ */
+ isa += 4;
+
+ while (*isa) {
+ const char *ext = isa++;
+ const char *ext_end = isa;
+ bool ext_err = false;
+
+ switch (*ext) {
+ case 'x':
+ case 'X':
+ log_warning("Vendor extensions are ignored in riscv,isa. Use riscv,isa-extensions instead.");
+ /*
+ * To skip an extension, we find its end.
+ * As multi-letter extensions must be split from other multi-letter
+ * extensions with an "_", the end of a multi-letter extension will
+ * either be the null character or the "_" at the start of the next
+ * multi-letter extension.
+ */
+ for (; *isa && *isa != '_'; ++isa)
+ ;
+ ext_err = true;
+ break;
+ case 's':
+ /*
+ * Workaround for invalid single-letter 's' & 'u' (QEMU).
+ * No need to set the bit in riscv_isa as 's' & 'u' are
+ * not valid ISA extensions. It works unless the first
+ * multi-letter extension in the ISA string begins with
+ * "Su" and is not prefixed with an underscore.
+ */
+ if (ext[-1] != '_' && ext[1] == 'u') {
+ ++isa;
+ ext_err = true;
+ break;
+ }
+ fallthrough;
+ case 'S':
+ case 'z':
+ case 'Z':
+ /*
+ * Before attempting to parse the extension itself, we find its end.
+ * As multi-letter extensions must be split from other multi-letter
+ * extensions with an "_", the end of a multi-letter extension will
+ * either be the null character or the "_" at the start of the next
+ * multi-letter extension.
+ *
+ * Next, as the extensions version is currently ignored, we
+ * eliminate that portion. This is done by parsing backwards from
+ * the end of the extension, removing any numbers. This may be a
+ * major or minor number however, so the process is repeated if a
+ * minor number was found.
+ *
+ * ext_end is intended to represent the first character *after* the
+ * name portion of an extension, but will be decremented to the last
+ * character itself while eliminating the extensions version number.
+ * A simple re-increment solves this problem.
+ */
+ for (; *isa && *isa != '_'; ++isa)
+ if (unlikely(!isalnum(*isa)))
+ ext_err = true;
+
+ ext_end = isa;
+ if (unlikely(ext_err))
+ break;
+
+ if (!isdigit(ext_end[-1]))
+ break;
+
+ while (isdigit(*--ext_end))
+ ;
+
+ if (tolower(ext_end[0]) != 'p' || !isdigit(ext_end[-1])) {
+ ++ext_end;
+ break;
+ }
+
+ while (isdigit(*--ext_end))
+ ;
+
+ ++ext_end;
+ break;
+ default:
+ /*
+ * Things are a little easier for single-letter extensions, as they
+ * are parsed forwards.
+ *
+ * After checking that our starting position is valid, we need to
+ * ensure that, when isa was incremented at the start of the loop,
+ * that it arrived at the start of the next extension.
+ *
+ * If we are already on a non-digit, there is nothing to do. Either
+ * we have a multi-letter extension's _, or the start of an
+ * extension.
+ *
+ * Otherwise we have found the current extension's major version
+ * number. Parse past it, and a subsequent p/minor version number
+ * if present. The `p` extension must not appear immediately after
+ * a number, so there is no fear of missing it.
+ *
+ */
+ if (unlikely(!isalpha(*ext))) {
+ ext_err = true;
+ break;
+ }
+
+ if (!isdigit(*isa))
+ break;
+
+ while (isdigit(*++isa))
+ ;
+
+ if (tolower(*isa) != 'p')
+ break;
+
+ if (!isdigit(*++isa)) {
+ --isa;
+ break;
+ }
+
+ while (isdigit(*++isa))
+ ;
+
+ break;
+ }
+
+ /*
+ * The parser expects that at the start of an iteration isa points to the
+ * first character of the next extension. As we stop parsing an extension
+ * on meeting a non-alphanumeric character, an extra increment is needed
+ * where the succeeding extension is a multi-letter prefixed with an "_".
+ */
+ if (*isa == '_')
+ ++isa;
+
+ if (unlikely(ext_err))
+ continue;
+ match_isa_ext(ext, ext_end);
+ }
+}
+
static inline bool supports_extension(char ext)
{
#if CONFIG_IS_ENABLED(RISCV_MMODE)
diff --git a/arch/riscv/include/asm/cpufeature.h b/arch/riscv/include/asm/cpufeature.h
new file mode 100644
index 00000000000..655180c993e
--- /dev/null
+++ b/arch/riscv/include/asm/cpufeature.h
@@ -0,0 +1,37 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#ifndef _ASM_CPUFEATURE_H
+#define _ASM_CPUFEATURE_H
+struct riscv_isa_ext_data {
+ const unsigned int id;
+ const char *name;
+ const char *property;
+ const unsigned int *subset_ext_ids;
+ const unsigned int subset_ext_size;
+ int (*validate)(const struct riscv_isa_ext_data *data, const unsigned long *isa_bitmap);
+};
+
+#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, 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), 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), 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)
+#endif
diff --git a/arch/riscv/include/asm/hwcap.h b/arch/riscv/include/asm/hwcap.h
new file mode 100644
index 00000000000..aa68ada6b2b
--- /dev/null
+++ b/arch/riscv/include/asm/hwcap.h
@@ -0,0 +1,105 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+#ifndef _ASM_RISCV_HWCAP_H
+#define _ASM_RISCV_HWCAP_H
+
+#define RISCV_ISA_EXT_a ('a' - 'a')
+#define RISCV_ISA_EXT_c ('c' - 'a')
+#define RISCV_ISA_EXT_d ('d' - 'a')
+#define RISCV_ISA_EXT_f ('f' - 'a')
+#define RISCV_ISA_EXT_h ('h' - 'a')
+#define RISCV_ISA_EXT_i ('i' - 'a')
+#define RISCV_ISA_EXT_m ('m' - 'a')
+#define RISCV_ISA_EXT_q ('q' - 'a')
+#define RISCV_ISA_EXT_v ('v' - 'a')
+
+/*
+ * These macros represent the logical IDs of each multi-letter RISC-V ISA
+ * extension and are used in the ISA bitmap. The logical IDs start from
+ * RISCV_ISA_EXT_BASE, which allows the 0-25 range to be reserved for single
+ * letter extensions. The maximum, RISCV_ISA_EXT_MAX, is defined in order
+ * to allocate the bitmap and may be increased when necessary.
+ *
+ * New extensions should just be added to the bottom, rather than added
+ * alphabetically, in order to avoid unnecessary shuffling.
+ */
+#define RISCV_ISA_EXT_BASE 26
+
+#define RISCV_ISA_EXT_SSCOFPMF 26
+#define RISCV_ISA_EXT_SSTC 27
+#define RISCV_ISA_EXT_SVINVAL 28
+#define RISCV_ISA_EXT_SVPBMT 29
+#define RISCV_ISA_EXT_ZBB 30
+#define RISCV_ISA_EXT_ZICBOM 31
+#define RISCV_ISA_EXT_ZIHINTPAUSE 32
+#define RISCV_ISA_EXT_SVNAPOT 33
+#define RISCV_ISA_EXT_ZICBOZ 34
+#define RISCV_ISA_EXT_SMAIA 35
+#define RISCV_ISA_EXT_SSAIA 36
+#define RISCV_ISA_EXT_ZBA 37
+#define RISCV_ISA_EXT_ZBS 38
+#define RISCV_ISA_EXT_ZICNTR 39
+#define RISCV_ISA_EXT_ZICSR 40
+#define RISCV_ISA_EXT_ZIFENCEI 41
+#define RISCV_ISA_EXT_ZIHPM 42
+#define RISCV_ISA_EXT_SMSTATEEN 43
+#define RISCV_ISA_EXT_ZICOND 44
+#define RISCV_ISA_EXT_ZBC 45
+#define RISCV_ISA_EXT_ZBKB 46
+#define RISCV_ISA_EXT_ZBKC 47
+#define RISCV_ISA_EXT_ZBKX 48
+#define RISCV_ISA_EXT_ZKND 49
+#define RISCV_ISA_EXT_ZKNE 50
+#define RISCV_ISA_EXT_ZKNH 51
+#define RISCV_ISA_EXT_ZKR 52
+#define RISCV_ISA_EXT_ZKSED 53
+#define RISCV_ISA_EXT_ZKSH 54
+#define RISCV_ISA_EXT_ZKT 55
+#define RISCV_ISA_EXT_ZVBB 56
+#define RISCV_ISA_EXT_ZVBC 57
+#define RISCV_ISA_EXT_ZVKB 58
+#define RISCV_ISA_EXT_ZVKG 59
+#define RISCV_ISA_EXT_ZVKNED 60
+#define RISCV_ISA_EXT_ZVKNHA 61
+#define RISCV_ISA_EXT_ZVKNHB 62
+#define RISCV_ISA_EXT_ZVKSED 63
+#define RISCV_ISA_EXT_ZVKSH 64
+#define RISCV_ISA_EXT_ZVKT 65
+#define RISCV_ISA_EXT_ZFH 66
+#define RISCV_ISA_EXT_ZFHMIN 67
+#define RISCV_ISA_EXT_ZIHINTNTL 68
+#define RISCV_ISA_EXT_ZVFH 69
+#define RISCV_ISA_EXT_ZVFHMIN 70
+#define RISCV_ISA_EXT_ZFA 71
+#define RISCV_ISA_EXT_ZTSO 72
+#define RISCV_ISA_EXT_ZACAS 73
+#define RISCV_ISA_EXT_ZVE32X 74
+#define RISCV_ISA_EXT_ZVE32F 75
+#define RISCV_ISA_EXT_ZVE64X 76
+#define RISCV_ISA_EXT_ZVE64F 77
+#define RISCV_ISA_EXT_ZVE64D 78
+#define RISCV_ISA_EXT_ZIMOP 79
+#define RISCV_ISA_EXT_ZCA 80
+#define RISCV_ISA_EXT_ZCB 81
+#define RISCV_ISA_EXT_ZCD 82
+#define RISCV_ISA_EXT_ZCF 83
+#define RISCV_ISA_EXT_ZCMOP 84
+#define RISCV_ISA_EXT_ZAWRS 85
+#define RISCV_ISA_EXT_SVVPTC 86
+#define RISCV_ISA_EXT_SMMPM 87
+#define RISCV_ISA_EXT_SMNPM 88
+#define RISCV_ISA_EXT_SSNPM 89
+
+#define RISCV_ISA_EXT_XLINUXENVCFG 127
+
+#define RISCV_ISA_EXT_MAX 128
+#define RISCV_ISA_EXT_INVALID U32_MAX
+
+#ifdef CONFIG_RISCV_M_MODE
+#define RISCV_ISA_EXT_SxAIA RISCV_ISA_EXT_SMAIA
+#define RISCV_ISA_EXT_SUPM RISCV_ISA_EXT_SMNPM
+#else
+#define RISCV_ISA_EXT_SxAIA RISCV_ISA_EXT_SSAIA
+#define RISCV_ISA_EXT_SUPM RISCV_ISA_EXT_SSNPM
+#endif
+
+#endif /* _ASM_RISCV_HWCAP_H */
--
2.34.1