1 files changed, 757 insertions, 32 deletions

diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
index a5ad00043104..3ed2359eae35 100644
--- a/arch/riscv/kernel/cpufeature.c
+++ b/arch/riscv/kernel/cpufeature.c
@@ -6,46 +6,549 @@
  * Copyright (C) 2017 SiFive
  */
 
+#include <linux/acpi.h>
+#include <linux/bitmap.h>
+#include <linux/cpu.h>
+#include <linux/cpuhotplug.h>
+#include <linux/ctype.h>
+#include <linux/log2.h>
+#include <linux/memory.h>
+#include <linux/module.h>
 #include <linux/of.h>
-#include <asm/processor.h>
+#include <asm/acpi.h>
+#include <asm/alternative.h>
+#include <asm/cacheflush.h>
+#include <asm/cpufeature.h>
 #include <asm/hwcap.h>
-#include <asm/smp.h>
-#include <asm/switch_to.h>
+#include <asm/patch.h>
+#include <asm/processor.h>
+#include <asm/sbi.h>
+#include <asm/vector.h>
+
+#define NUM_ALPHA_EXTS ('z' - 'a' + 1)
 
 unsigned long elf_hwcap __read_mostly;
-#ifdef CONFIG_FPU
-bool has_fpu __read_mostly;
-#endif
 
-void riscv_fill_hwcap(void)
+/* Host ISA bitmap */
+static DECLARE_BITMAP(riscv_isa, RISCV_ISA_EXT_MAX) __read_mostly;
+
+/* Per-cpu ISA extensions. */
+struct riscv_isainfo hart_isa[NR_CPUS];
+
+/**
+ * riscv_isa_extension_base() - Get base extension word
+ *
+ * @isa_bitmap: ISA bitmap to use
+ * Return: base extension word as unsigned long value
+ *
+ * NOTE: If isa_bitmap is NULL then Host ISA bitmap will be used.
+ */
+unsigned long riscv_isa_extension_base(const unsigned long *isa_bitmap)
+{
+	if (!isa_bitmap)
+		return riscv_isa[0];
+	return isa_bitmap[0];
+}
+EXPORT_SYMBOL_GPL(riscv_isa_extension_base);
+
+/**
+ * __riscv_isa_extension_available() - Check whether given extension
+ * is available or not
+ *
+ * @isa_bitmap: ISA bitmap to use
+ * @bit: bit position of the desired extension
+ * Return: true or false
+ *
+ * NOTE: If isa_bitmap is NULL then Host ISA bitmap will be used.
+ */
+bool __riscv_isa_extension_available(const unsigned long *isa_bitmap, unsigned int bit)
+{
+	const unsigned long *bmap = (isa_bitmap) ? isa_bitmap : riscv_isa;
+
+	if (bit >= RISCV_ISA_EXT_MAX)
+		return false;
+
+	return test_bit(bit, bmap) ? true : false;
+}
+EXPORT_SYMBOL_GPL(__riscv_isa_extension_available);
+
+static bool riscv_isa_extension_check(int id)
+{
+	switch (id) {
+	case RISCV_ISA_EXT_ZICBOM:
+		if (!riscv_cbom_block_size) {
+			pr_err("Zicbom detected in ISA string, disabling as no cbom-block-size found\n");
+			return false;
+		} else if (!is_power_of_2(riscv_cbom_block_size)) {
+			pr_err("Zicbom disabled as cbom-block-size present, but is not a power-of-2\n");
+			return false;
+		}
+		return true;
+	case RISCV_ISA_EXT_ZICBOZ:
+		if (!riscv_cboz_block_size) {
+			pr_err("Zicboz detected in ISA string, disabling as no cboz-block-size found\n");
+			return false;
+		} else if (!is_power_of_2(riscv_cboz_block_size)) {
+			pr_err("Zicboz disabled as cboz-block-size present, but is not a power-of-2\n");
+			return false;
+		}
+		return true;
+	case RISCV_ISA_EXT_INVALID:
+		return false;
+	}
+
+	return true;
+}
+
+#define _RISCV_ISA_EXT_DATA(_name, _id, _subset_exts, _subset_exts_size) {	\
+	.name = #_name,								\
+	.property = #_name,							\
+	.id = _id,								\
+	.subset_ext_ids = _subset_exts,						\
+	.subset_ext_size = _subset_exts_size					\
+}
+
+#define __RISCV_ISA_EXT_DATA(_name, _id) _RISCV_ISA_EXT_DATA(_name, _id, NULL, 0)
+
+/* 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))
+
+/* 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))
+
+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
+};
+
+/*
+ * 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
+};
+
+/*
+ * 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_DATA(c, RISCV_ISA_EXT_c),
+	__RISCV_ISA_EXT_DATA(v, RISCV_ISA_EXT_v),
+	__RISCV_ISA_EXT_DATA(h, RISCV_ISA_EXT_h),
+	__RISCV_ISA_EXT_SUPERSET(zicbom, RISCV_ISA_EXT_ZICBOM, riscv_xlinuxenvcfg_exts),
+	__RISCV_ISA_EXT_SUPERSET(zicboz, RISCV_ISA_EXT_ZICBOZ, riscv_xlinuxenvcfg_exts),
+	__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(zacas, RISCV_ISA_EXT_ZACAS),
+	__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(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_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(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_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(xandespmu, RISCV_ISA_EXT_XANDESPMU),
+};
+
+const size_t riscv_isa_ext_count = ARRAY_SIZE(riscv_isa_ext);
+
+static void __init match_isa_ext(const struct riscv_isa_ext_data *ext, const char *name,
+				 const char *name_end, struct riscv_isainfo *isainfo)
+{
+	if ((name_end - name == strlen(ext->name)) &&
+	     !strncasecmp(name, ext->name, name_end - name)) {
+		/*
+		 * If this is a bundle, enable all the ISA extensions that
+		 * comprise the bundle.
+		 */
+		if (ext->subset_ext_size) {
+			for (int i = 0; i < ext->subset_ext_size; i++) {
+				if (riscv_isa_extension_check(ext->subset_ext_ids[i]))
+					set_bit(ext->subset_ext_ids[i], isainfo->isa);
+			}
+		}
+
+		/*
+		 * This is valid even for bundle extensions which uses the RISCV_ISA_EXT_INVALID id
+		 * (rejected by riscv_isa_extension_check()).
+		 */
+		if (riscv_isa_extension_check(ext->id))
+			set_bit(ext->id, isainfo->isa);
+	}
+}
+
+static void __init riscv_parse_isa_string(unsigned long *this_hwcap, struct riscv_isainfo *isainfo,
+					  unsigned long *isa2hwcap, 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_long = false, ext_err = false;
+
+		switch (*ext) {
+		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 'x':
+		case 'X':
+		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.
+			 */
+			ext_long = true;
+			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;
+		if (!ext_long) {
+			int nr = tolower(*ext) - 'a';
+
+			if (riscv_isa_extension_check(nr)) {
+				*this_hwcap |= isa2hwcap[nr];
+				set_bit(nr, isainfo->isa);
+			}
+		} else {
+			for (int i = 0; i < riscv_isa_ext_count; i++)
+				match_isa_ext(&riscv_isa_ext[i], ext, ext_end, isainfo);
+		}
+	}
+}
+
+static void __init riscv_fill_hwcap_from_isa_string(unsigned long *isa2hwcap)
 {
 	struct device_node *node;
 	const char *isa;
-	size_t i;
-	static unsigned long isa2hwcap[256] = {0};
-
-	isa2hwcap['i'] = isa2hwcap['I'] = COMPAT_HWCAP_ISA_I;
-	isa2hwcap['m'] = isa2hwcap['M'] = COMPAT_HWCAP_ISA_M;
-	isa2hwcap['a'] = isa2hwcap['A'] = COMPAT_HWCAP_ISA_A;
-	isa2hwcap['f'] = isa2hwcap['F'] = COMPAT_HWCAP_ISA_F;
-	isa2hwcap['d'] = isa2hwcap['D'] = COMPAT_HWCAP_ISA_D;
-	isa2hwcap['c'] = isa2hwcap['C'] = COMPAT_HWCAP_ISA_C;
+	int rc;
+	struct acpi_table_header *rhct;
+	acpi_status status;
+	unsigned int cpu;
 
-	elf_hwcap = 0;
+	if (!acpi_disabled) {
+		status = acpi_get_table(ACPI_SIG_RHCT, 0, &rhct);
+		if (ACPI_FAILURE(status))
+			return;
+	}
 
-	for_each_of_cpu_node(node) {
+	for_each_possible_cpu(cpu) {
+		struct riscv_isainfo *isainfo = &hart_isa[cpu];
 		unsigned long this_hwcap = 0;
 
-		if (riscv_of_processor_hartid(node) < 0)
-			continue;
+		if (acpi_disabled) {
+			node = of_cpu_device_node_get(cpu);
+			if (!node) {
+				pr_warn("Unable to find cpu node\n");
+				continue;
+			}
 
-		if (of_property_read_string(node, "riscv,isa", &isa)) {
-			pr_warn("Unable to find \"riscv,isa\" devicetree entry\n");
-			continue;
+			rc = of_property_read_string(node, "riscv,isa", &isa);
+			of_node_put(node);
+			if (rc) {
+				pr_warn("Unable to find \"riscv,isa\" devicetree entry\n");
+				continue;
+			}
+		} else {
+			rc = acpi_get_riscv_isa(rhct, cpu, &isa);
+			if (rc < 0) {
+				pr_warn("Unable to get ISA for the hart - %d\n", cpu);
+				continue;
+			}
 		}
 
-		for (i = 0; i < strlen(isa); ++i)
-			this_hwcap |= isa2hwcap[(unsigned char)(isa[i])];
+		riscv_parse_isa_string(&this_hwcap, isainfo, isa2hwcap, isa);
+
+		/*
+		 * These ones were as they were part of the base ISA when the
+		 * port & dt-bindings were upstreamed, and so can be set
+		 * unconditionally where `i` is in riscv,isa on DT systems.
+		 */
+		if (acpi_disabled) {
+			set_bit(RISCV_ISA_EXT_ZICSR, isainfo->isa);
+			set_bit(RISCV_ISA_EXT_ZIFENCEI, isainfo->isa);
+			set_bit(RISCV_ISA_EXT_ZICNTR, isainfo->isa);
+			set_bit(RISCV_ISA_EXT_ZIHPM, isainfo->isa);
+		}
+
+		/*
+		 * "V" in ISA strings is ambiguous in practice: it should mean
+		 * just the standard V-1.0 but vendors aren't well behaved.
+		 * Many vendors with T-Head CPU cores which implement the 0.7.1
+		 * version of the vector specification put "v" into their DTs.
+		 * CPU cores with the ratified spec will contain non-zero
+		 * marchid.
+		 */
+		if (acpi_disabled && riscv_cached_mvendorid(cpu) == THEAD_VENDOR_ID &&
+		    riscv_cached_marchid(cpu) == 0x0) {
+			this_hwcap &= ~isa2hwcap[RISCV_ISA_EXT_v];
+			clear_bit(RISCV_ISA_EXT_v, isainfo->isa);
+		}
 
 		/*
 		 * All "okay" hart should have same isa. Set HWCAP based on
@@ -56,19 +559,241 @@ void riscv_fill_hwcap(void)
 			elf_hwcap &= this_hwcap;
 		else
 			elf_hwcap = this_hwcap;
+
+		if (bitmap_empty(riscv_isa, RISCV_ISA_EXT_MAX))
+			bitmap_copy(riscv_isa, isainfo->isa, RISCV_ISA_EXT_MAX);
+		else
+			bitmap_and(riscv_isa, riscv_isa, isainfo->isa, RISCV_ISA_EXT_MAX);
+	}
+
+	if (!acpi_disabled && rhct)
+		acpi_put_table((struct acpi_table_header *)rhct);
+}
+
+static int __init riscv_fill_hwcap_from_ext_list(unsigned long *isa2hwcap)
+{
+	unsigned int cpu;
+
+	for_each_possible_cpu(cpu) {
+		unsigned long this_hwcap = 0;
+		struct device_node *cpu_node;
+		struct riscv_isainfo *isainfo = &hart_isa[cpu];
+
+		cpu_node = of_cpu_device_node_get(cpu);
+		if (!cpu_node) {
+			pr_warn("Unable to find cpu node\n");
+			continue;
+		}
+
+		if (!of_property_present(cpu_node, "riscv,isa-extensions")) {
+			of_node_put(cpu_node);
+			continue;
+		}
+
+		for (int i = 0; i < riscv_isa_ext_count; i++) {
+			const struct riscv_isa_ext_data *ext = &riscv_isa_ext[i];
+
+			if (of_property_match_string(cpu_node, "riscv,isa-extensions",
+						     ext->property) < 0)
+				continue;
+
+			if (ext->subset_ext_size) {
+				for (int j = 0; j < ext->subset_ext_size; j++) {
+					if (riscv_isa_extension_check(ext->subset_ext_ids[i]))
+						set_bit(ext->subset_ext_ids[j], isainfo->isa);
+				}
+			}
+
+			if (riscv_isa_extension_check(ext->id)) {
+				set_bit(ext->id, isainfo->isa);
+
+				/* Only single letter extensions get set in hwcap */
+				if (strnlen(riscv_isa_ext[i].name, 2) == 1)
+					this_hwcap |= isa2hwcap[riscv_isa_ext[i].id];
+			}
+		}
+
+		of_node_put(cpu_node);
+
+		/*
+		 * All "okay" harts should have same isa. Set HWCAP based on
+		 * common capabilities of every "okay" hart, in case they don't.
+		 */
+		if (elf_hwcap)
+			elf_hwcap &= this_hwcap;
+		else
+			elf_hwcap = this_hwcap;
+
+		if (bitmap_empty(riscv_isa, RISCV_ISA_EXT_MAX))
+			bitmap_copy(riscv_isa, isainfo->isa, RISCV_ISA_EXT_MAX);
+		else
+			bitmap_and(riscv_isa, riscv_isa, isainfo->isa, RISCV_ISA_EXT_MAX);
+	}
+
+	if (bitmap_empty(riscv_isa, RISCV_ISA_EXT_MAX))
+		return -ENOENT;
+
+	return 0;
+}
+
+#ifdef CONFIG_RISCV_ISA_FALLBACK
+bool __initdata riscv_isa_fallback = true;
+#else
+bool __initdata riscv_isa_fallback;
+static int __init riscv_isa_fallback_setup(char *__unused)
+{
+	riscv_isa_fallback = true;
+	return 1;
+}
+early_param("riscv_isa_fallback", riscv_isa_fallback_setup);
+#endif
+
+void __init riscv_fill_hwcap(void)
+{
+	char print_str[NUM_ALPHA_EXTS + 1];
+	unsigned long isa2hwcap[26] = {0};
+	int i, j;
+
+	isa2hwcap['i' - 'a'] = COMPAT_HWCAP_ISA_I;
+	isa2hwcap['m' - 'a'] = COMPAT_HWCAP_ISA_M;
+	isa2hwcap['a' - 'a'] = COMPAT_HWCAP_ISA_A;
+	isa2hwcap['f' - 'a'] = COMPAT_HWCAP_ISA_F;
+	isa2hwcap['d' - 'a'] = COMPAT_HWCAP_ISA_D;
+	isa2hwcap['c' - 'a'] = COMPAT_HWCAP_ISA_C;
+	isa2hwcap['v' - 'a'] = COMPAT_HWCAP_ISA_V;
+
+	if (!acpi_disabled) {
+		riscv_fill_hwcap_from_isa_string(isa2hwcap);
+	} else {
+		int ret = riscv_fill_hwcap_from_ext_list(isa2hwcap);
+
+		if (ret && riscv_isa_fallback) {
+			pr_info("Falling back to deprecated \"riscv,isa\"\n");
+			riscv_fill_hwcap_from_isa_string(isa2hwcap);
+		}
 	}
 
-	/* We don't support systems with F but without D, so mask those out
-	 * here. */
+	/*
+	 * We don't support systems with F but without D, so mask those out
+	 * here.
+	 */
 	if ((elf_hwcap & COMPAT_HWCAP_ISA_F) && !(elf_hwcap & COMPAT_HWCAP_ISA_D)) {
 		pr_info("This kernel does not support systems with F but not D\n");
 		elf_hwcap &= ~COMPAT_HWCAP_ISA_F;
 	}
 
-	pr_info("elf_hwcap is 0x%lx\n", elf_hwcap);
+	if (elf_hwcap & COMPAT_HWCAP_ISA_V) {
+		riscv_v_setup_vsize();
+		/*
+		 * ISA string in device tree might have 'v' flag, but
+		 * CONFIG_RISCV_ISA_V is disabled in kernel.
+		 * Clear V flag in elf_hwcap if CONFIG_RISCV_ISA_V is disabled.
+		 */
+		if (!IS_ENABLED(CONFIG_RISCV_ISA_V))
+			elf_hwcap &= ~COMPAT_HWCAP_ISA_V;
+	}
 
-#ifdef CONFIG_FPU
-	if (elf_hwcap & (COMPAT_HWCAP_ISA_F | COMPAT_HWCAP_ISA_D))
-		has_fpu = true;
-#endif
+	memset(print_str, 0, sizeof(print_str));
+	for (i = 0, j = 0; i < NUM_ALPHA_EXTS; i++)
+		if (riscv_isa[0] & BIT_MASK(i))
+			print_str[j++] = (char)('a' + i);
+	pr_info("riscv: base ISA extensions %s\n", print_str);
+
+	memset(print_str, 0, sizeof(print_str));
+	for (i = 0, j = 0; i < NUM_ALPHA_EXTS; i++)
+		if (elf_hwcap & BIT_MASK(i))
+			print_str[j++] = (char)('a' + i);
+	pr_info("riscv: ELF capabilities %s\n", print_str);
 }
+
+unsigned long riscv_get_elf_hwcap(void)
+{
+	unsigned long hwcap;
+
+	hwcap = (elf_hwcap & ((1UL << RISCV_ISA_EXT_BASE) - 1));
+
+	if (!riscv_v_vstate_ctrl_user_allowed())
+		hwcap &= ~COMPAT_HWCAP_ISA_V;
+
+	return hwcap;
+}
+
+void riscv_user_isa_enable(void)
+{
+	if (riscv_cpu_has_extension_unlikely(smp_processor_id(), RISCV_ISA_EXT_ZICBOZ))
+		csr_set(CSR_ENVCFG, ENVCFG_CBZE);
+}
+
+#ifdef CONFIG_RISCV_ALTERNATIVE
+/*
+ * Alternative patch sites consider 48 bits when determining when to patch
+ * the old instruction sequence with the new. These bits are broken into a
+ * 16-bit vendor ID and a 32-bit patch ID. A non-zero vendor ID means the
+ * patch site is for an erratum, identified by the 32-bit patch ID. When
+ * the vendor ID is zero, the patch site is for a cpufeature. cpufeatures
+ * further break down patch ID into two 16-bit numbers. The lower 16 bits
+ * are the cpufeature ID and the upper 16 bits are used for a value specific
+ * to the cpufeature and patch site. If the upper 16 bits are zero, then it
+ * implies no specific value is specified. cpufeatures that want to control
+ * patching on a per-site basis will provide non-zero values and implement
+ * checks here. The checks return true when patching should be done, and
+ * false otherwise.
+ */
+static bool riscv_cpufeature_patch_check(u16 id, u16 value)
+{
+	if (!value)
+		return true;
+
+	switch (id) {
+	case RISCV_ISA_EXT_ZICBOZ:
+		/*
+		 * Zicboz alternative applications provide the maximum
+		 * supported block size order, or zero when it doesn't
+		 * matter. If the current block size exceeds the maximum,
+		 * then the alternative cannot be applied.
+		 */
+		return riscv_cboz_block_size <= (1U << value);
+	}
+
+	return false;
+}
+
+void __init_or_module riscv_cpufeature_patch_func(struct alt_entry *begin,
+						  struct alt_entry *end,
+						  unsigned int stage)
+{
+	struct alt_entry *alt;
+	void *oldptr, *altptr;
+	u16 id, value;
+
+	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);
+
+		if (id >= RISCV_ISA_EXT_MAX) {
+			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;
+
+		oldptr = ALT_OLD_PTR(alt);
+		altptr = ALT_ALT_PTR(alt);
+
+		mutex_lock(&text_mutex);
+		patch_text_nosync(oldptr, altptr, alt->alt_len);
+		riscv_alternative_fix_offsets(oldptr, alt->alt_len, oldptr - altptr);
+		mutex_unlock(&text_mutex);
+	}
+}
+#endif