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-rw-r--r--arch/riscv/kernel/cpufeature.c299
1 files changed, 267 insertions, 32 deletions
diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
index 8677788133..79a5a35fab 100644
--- a/arch/riscv/kernel/cpufeature.c
+++ b/arch/riscv/kernel/cpufeature.c
@@ -8,8 +8,10 @@
#include <linux/acpi.h>
#include <linux/bitmap.h>
+#include <linux/cpu.h>
#include <linux/cpuhotplug.h>
#include <linux/ctype.h>
+#include <linux/jump_label.h>
#include <linux/log2.h>
#include <linux/memory.h>
#include <linux/module.h>
@@ -45,6 +47,8 @@ struct riscv_isainfo hart_isa[NR_CPUS];
/* Performance information */
DEFINE_PER_CPU(long, misaligned_access_speed);
+static cpumask_t fast_misaligned_access;
+
/**
* riscv_isa_extension_base() - Get base extension word
*
@@ -71,7 +75,7 @@ EXPORT_SYMBOL_GPL(riscv_isa_extension_base);
*
* NOTE: If isa_bitmap is NULL then Host ISA bitmap will be used.
*/
-bool __riscv_isa_extension_available(const unsigned long *isa_bitmap, int bit)
+bool __riscv_isa_extension_available(const unsigned long *isa_bitmap, unsigned int bit)
{
const unsigned long *bmap = (isa_bitmap) ? isa_bitmap : riscv_isa;
@@ -103,17 +107,111 @@ static bool riscv_isa_extension_check(int id)
return false;
}
return true;
+ case RISCV_ISA_EXT_INVALID:
+ return false;
}
return true;
}
-#define __RISCV_ISA_EXT_DATA(_name, _id) { \
- .name = #_name, \
- .property = #_name, \
- .id = _id, \
+#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.
@@ -161,23 +259,57 @@ const struct riscv_isa_ext_data riscv_isa_ext[] = {
__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(b, RISCV_ISA_EXT_b),
- __RISCV_ISA_EXT_DATA(k, RISCV_ISA_EXT_k),
- __RISCV_ISA_EXT_DATA(j, RISCV_ISA_EXT_j),
- __RISCV_ISA_EXT_DATA(p, RISCV_ISA_EXT_p),
__RISCV_ISA_EXT_DATA(v, RISCV_ISA_EXT_v),
__RISCV_ISA_EXT_DATA(h, RISCV_ISA_EXT_h),
- __RISCV_ISA_EXT_DATA(zicbom, RISCV_ISA_EXT_ZICBOM),
- __RISCV_ISA_EXT_DATA(zicboz, RISCV_ISA_EXT_ZICBOZ),
+ __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),
@@ -190,6 +322,31 @@ const struct riscv_isa_ext_data riscv_isa_ext[] = {
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)
{
@@ -322,14 +479,6 @@ static void __init riscv_parse_isa_string(unsigned long *this_hwcap, struct risc
if (*isa == '_')
++isa;
-#define SET_ISA_EXT_MAP(name, bit) \
- do { \
- if ((ext_end - ext == strlen(name)) && \
- !strncasecmp(ext, name, strlen(name)) && \
- riscv_isa_extension_check(bit)) \
- set_bit(bit, isainfo->isa); \
- } while (false) \
-
if (unlikely(ext_err))
continue;
if (!ext_long) {
@@ -341,10 +490,8 @@ static void __init riscv_parse_isa_string(unsigned long *this_hwcap, struct risc
}
} else {
for (int i = 0; i < riscv_isa_ext_count; i++)
- SET_ISA_EXT_MAP(riscv_isa_ext[i].name,
- riscv_isa_ext[i].id);
+ match_isa_ext(&riscv_isa_ext[i], ext, ext_end, isainfo);
}
-#undef SET_ISA_EXT_MAP
}
}
@@ -457,18 +604,26 @@ static int __init riscv_fill_hwcap_from_ext_list(unsigned long *isa2hwcap)
}
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",
- riscv_isa_ext[i].property) < 0)
+ ext->property) < 0)
continue;
- if (!riscv_isa_extension_check(riscv_isa_ext[i].id))
- 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);
+ }
+ }
- /* 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];
+ if (riscv_isa_extension_check(ext->id)) {
+ set_bit(ext->id, isainfo->isa);
- set_bit(riscv_isa_ext[i].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);
@@ -658,6 +813,16 @@ static int check_unaligned_access(void *param)
(speed == RISCV_HWPROBE_MISALIGNED_FAST) ? "fast" : "slow");
per_cpu(misaligned_access_speed, cpu) = speed;
+
+ /*
+ * Set the value of fast_misaligned_access of a CPU. These operations
+ * are atomic to avoid race conditions.
+ */
+ if (speed == RISCV_HWPROBE_MISALIGNED_FAST)
+ cpumask_set_cpu(cpu, &fast_misaligned_access);
+ else
+ cpumask_clear_cpu(cpu, &fast_misaligned_access);
+
return 0;
}
@@ -670,13 +835,69 @@ static void check_unaligned_access_nonboot_cpu(void *param)
check_unaligned_access(pages[cpu]);
}
+DEFINE_STATIC_KEY_FALSE(fast_misaligned_access_speed_key);
+
+static void modify_unaligned_access_branches(cpumask_t *mask, int weight)
+{
+ if (cpumask_weight(mask) == weight)
+ static_branch_enable_cpuslocked(&fast_misaligned_access_speed_key);
+ else
+ static_branch_disable_cpuslocked(&fast_misaligned_access_speed_key);
+}
+
+static void set_unaligned_access_static_branches_except_cpu(int cpu)
+{
+ /*
+ * Same as set_unaligned_access_static_branches, except excludes the
+ * given CPU from the result. When a CPU is hotplugged into an offline
+ * state, this function is called before the CPU is set to offline in
+ * the cpumask, and thus the CPU needs to be explicitly excluded.
+ */
+
+ cpumask_t fast_except_me;
+
+ cpumask_and(&fast_except_me, &fast_misaligned_access, cpu_online_mask);
+ cpumask_clear_cpu(cpu, &fast_except_me);
+
+ modify_unaligned_access_branches(&fast_except_me, num_online_cpus() - 1);
+}
+
+static void set_unaligned_access_static_branches(void)
+{
+ /*
+ * This will be called after check_unaligned_access_all_cpus so the
+ * result of unaligned access speed for all CPUs will be available.
+ *
+ * To avoid the number of online cpus changing between reading
+ * cpu_online_mask and calling num_online_cpus, cpus_read_lock must be
+ * held before calling this function.
+ */
+
+ cpumask_t fast_and_online;
+
+ cpumask_and(&fast_and_online, &fast_misaligned_access, cpu_online_mask);
+
+ modify_unaligned_access_branches(&fast_and_online, num_online_cpus());
+}
+
+static int lock_and_set_unaligned_access_static_branch(void)
+{
+ cpus_read_lock();
+ set_unaligned_access_static_branches();
+ cpus_read_unlock();
+
+ return 0;
+}
+
+arch_initcall_sync(lock_and_set_unaligned_access_static_branch);
+
static int riscv_online_cpu(unsigned int cpu)
{
static struct page *buf;
/* We are already set since the last check */
if (per_cpu(misaligned_access_speed, cpu) != RISCV_HWPROBE_MISALIGNED_UNKNOWN)
- return 0;
+ goto exit;
buf = alloc_pages(GFP_KERNEL, MISALIGNED_BUFFER_ORDER);
if (!buf) {
@@ -686,6 +907,17 @@ static int riscv_online_cpu(unsigned int cpu)
check_unaligned_access(buf);
__free_pages(buf, MISALIGNED_BUFFER_ORDER);
+
+exit:
+ set_unaligned_access_static_branches();
+
+ return 0;
+}
+
+static int riscv_offline_cpu(unsigned int cpu)
+{
+ set_unaligned_access_static_branches_except_cpu(cpu);
+
return 0;
}
@@ -720,9 +952,12 @@ static int check_unaligned_access_all_cpus(void)
/* Check core 0. */
smp_call_on_cpu(0, check_unaligned_access, bufs[0], true);
- /* Setup hotplug callback for any new CPUs that come online. */
+ /*
+ * Setup hotplug callbacks for any new CPUs that come online or go
+ * offline.
+ */
cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN, "riscv:online",
- riscv_online_cpu, NULL);
+ riscv_online_cpu, riscv_offline_cpu);
out:
unaligned_emulation_finish();