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RISC-V: Move the hwprobe syscall to its own file

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As Palmer says, hwprobe is "sort of its own thing now, and it's only
going to get bigger..."

Suggested-by: Palmer Dabbelt <palmer@dabbelt.com>
Signed-off-by: Andrew Jones <ajones@ventanamicro.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20231122164700.127954-8-ajones@ventanamicro.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
This commit is contained in:
Andrew Jones 2023-11-22 17:47:03 +01:00 committed by Palmer Dabbelt
parent 36d842d654
commit 53b2b22850
No known key found for this signature in database
GPG Key ID: 2E1319F35FBB1889
3 changed files with 290 additions and 285 deletions
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1
arch/riscv/kernel/Makefile
View File

@ -50,6 +50,7 @@ obj-y += setup.o
obj-y += signal.o
obj-y += syscall_table.o
obj-y += sys_riscv.o
obj-y += sys_hwprobe.o
obj-y += time.o
obj-y += traps.o
obj-y += riscv_ksyms.o

289
arch/riscv/kernel/sys_hwprobe.c Normal file
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@ -0,0 +1,289 @@
// SPDX-License-Identifier: GPL-2.0-only
/*
* The hwprobe interface, for allowing userspace to probe to see which features
* are supported by the hardware. See Documentation/arch/riscv/hwprobe.rst for
* more details.
*/
#include <linux/syscalls.h>
#include <asm/cacheflush.h>
#include <asm/cpufeature.h>
#include <asm/hwprobe.h>
#include <asm/sbi.h>
#include <asm/switch_to.h>
#include <asm/uaccess.h>
#include <asm/unistd.h>
#include <asm/vector.h>
#include <vdso/vsyscall.h>
static void hwprobe_arch_id(struct riscv_hwprobe *pair,
const struct cpumask *cpus)
{
u64 id = -1ULL;
bool first = true;
int cpu;
for_each_cpu(cpu, cpus) {
u64 cpu_id;
switch (pair->key) {
case RISCV_HWPROBE_KEY_MVENDORID:
cpu_id = riscv_cached_mvendorid(cpu);
break;
case RISCV_HWPROBE_KEY_MIMPID:
cpu_id = riscv_cached_mimpid(cpu);
break;
case RISCV_HWPROBE_KEY_MARCHID:
cpu_id = riscv_cached_marchid(cpu);
break;
}
if (first) {
id = cpu_id;
first = false;
}
/*
* If there's a mismatch for the given set, return -1 in the
* value.
*/
if (id != cpu_id) {
id = -1ULL;
break;
}
}
pair->value = id;
}
static void hwprobe_isa_ext0(struct riscv_hwprobe *pair,
const struct cpumask *cpus)
{
int cpu;
u64 missing = 0;
pair->value = 0;
if (has_fpu())
pair->value |= RISCV_HWPROBE_IMA_FD;
if (riscv_isa_extension_available(NULL, c))
pair->value |= RISCV_HWPROBE_IMA_C;
if (has_vector())
pair->value |= RISCV_HWPROBE_IMA_V;
/*
* Loop through and record extensions that 1) anyone has, and 2) anyone
* doesn't have.
*/
for_each_cpu(cpu, cpus) {
struct riscv_isainfo *isainfo = &hart_isa[cpu];
#define EXT_KEY(ext) \
do { \
if (__riscv_isa_extension_available(isainfo->isa, RISCV_ISA_EXT_##ext)) \
pair->value |= RISCV_HWPROBE_EXT_##ext; \
else \
missing |= RISCV_HWPROBE_EXT_##ext; \
} while (false)
/*
* Only use EXT_KEY() for extensions which can be exposed to userspace,
* regardless of the kernel's configuration, as no other checks, besides
* presence in the hart_isa bitmap, are made.
*/
EXT_KEY(ZBA);
EXT_KEY(ZBB);
EXT_KEY(ZBS);
EXT_KEY(ZICBOZ);
#undef EXT_KEY
}
/* Now turn off reporting features if any CPU is missing it. */
pair->value &= ~missing;
}
static bool hwprobe_ext0_has(const struct cpumask *cpus, unsigned long ext)
{
struct riscv_hwprobe pair;
hwprobe_isa_ext0(&pair, cpus);
return (pair.value & ext);
}
static u64 hwprobe_misaligned(const struct cpumask *cpus)
{
int cpu;
u64 perf = -1ULL;
for_each_cpu(cpu, cpus) {
int this_perf = per_cpu(misaligned_access_speed, cpu);
if (perf == -1ULL)
perf = this_perf;
if (perf != this_perf) {
perf = RISCV_HWPROBE_MISALIGNED_UNKNOWN;
break;
}
}
if (perf == -1ULL)
return RISCV_HWPROBE_MISALIGNED_UNKNOWN;
return perf;
}
static void hwprobe_one_pair(struct riscv_hwprobe *pair,
const struct cpumask *cpus)
{
switch (pair->key) {
case RISCV_HWPROBE_KEY_MVENDORID:
case RISCV_HWPROBE_KEY_MARCHID:
case RISCV_HWPROBE_KEY_MIMPID:
hwprobe_arch_id(pair, cpus);
break;
/*
* The kernel already assumes that the base single-letter ISA
* extensions are supported on all harts, and only supports the
* IMA base, so just cheat a bit here and tell that to
* userspace.
*/
case RISCV_HWPROBE_KEY_BASE_BEHAVIOR:
pair->value = RISCV_HWPROBE_BASE_BEHAVIOR_IMA;
break;
case RISCV_HWPROBE_KEY_IMA_EXT_0:
hwprobe_isa_ext0(pair, cpus);
break;
case RISCV_HWPROBE_KEY_CPUPERF_0:
pair->value = hwprobe_misaligned(cpus);
break;
case RISCV_HWPROBE_KEY_ZICBOZ_BLOCK_SIZE:
pair->value = 0;
if (hwprobe_ext0_has(cpus, RISCV_HWPROBE_EXT_ZICBOZ))
pair->value = riscv_cboz_block_size;
break;
/*
* For forward compatibility, unknown keys don't fail the whole
* call, but get their element key set to -1 and value set to 0
* indicating they're unrecognized.
*/
default:
pair->key = -1;
pair->value = 0;
break;
}
}
static int do_riscv_hwprobe(struct riscv_hwprobe __user *pairs,
size_t pair_count, size_t cpusetsize,
unsigned long __user *cpus_user,
unsigned int flags)
{
size_t out;
int ret;
cpumask_t cpus;
/* Check the reserved flags. */
if (flags != 0)
return -EINVAL;
/*
* The interface supports taking in a CPU mask, and returns values that
* are consistent across that mask. Allow userspace to specify NULL and
* 0 as a shortcut to all online CPUs.
*/
cpumask_clear(&cpus);
if (!cpusetsize && !cpus_user) {
cpumask_copy(&cpus, cpu_online_mask);
} else {
if (cpusetsize > cpumask_size())
cpusetsize = cpumask_size();
ret = copy_from_user(&cpus, cpus_user, cpusetsize);
if (ret)
return -EFAULT;
/*
* Userspace must provide at least one online CPU, without that
* there's no way to define what is supported.
*/
cpumask_and(&cpus, &cpus, cpu_online_mask);
if (cpumask_empty(&cpus))
return -EINVAL;
}
for (out = 0; out < pair_count; out++, pairs++) {
struct riscv_hwprobe pair;
if (get_user(pair.key, &pairs->key))
return -EFAULT;
pair.value = 0;
hwprobe_one_pair(&pair, &cpus);
ret = put_user(pair.key, &pairs->key);
if (ret == 0)
ret = put_user(pair.value, &pairs->value);
if (ret)
return -EFAULT;
}
return 0;
}
#ifdef CONFIG_MMU
static int __init init_hwprobe_vdso_data(void)
{
struct vdso_data *vd = __arch_get_k_vdso_data();
struct arch_vdso_data *avd = &vd->arch_data;
u64 id_bitsmash = 0;
struct riscv_hwprobe pair;
int key;
/*
* Initialize vDSO data with the answers for the "all CPUs" case, to
* save a syscall in the common case.
*/
for (key = 0; key <= RISCV_HWPROBE_MAX_KEY; key++) {
pair.key = key;
hwprobe_one_pair(&pair, cpu_online_mask);
WARN_ON_ONCE(pair.key < 0);
avd->all_cpu_hwprobe_values[key] = pair.value;
/*
* Smash together the vendor, arch, and impl IDs to see if
* they're all 0 or any negative.
*/
if (key <= RISCV_HWPROBE_KEY_MIMPID)
id_bitsmash |= pair.value;
}
/*
* If the arch, vendor, and implementation ID are all the same across
* all harts, then assume all CPUs are the same, and allow the vDSO to
* answer queries for arbitrary masks. However if all values are 0 (not
* populated) or any value returns -1 (varies across CPUs), then the
* vDSO should defer to the kernel for exotic cpu masks.
*/
avd->homogeneous_cpus = id_bitsmash != 0 && id_bitsmash != -1;
return 0;
}
arch_initcall_sync(init_hwprobe_vdso_data);
#endif /* CONFIG_MMU */
SYSCALL_DEFINE5(riscv_hwprobe, struct riscv_hwprobe __user *, pairs,
size_t, pair_count, size_t, cpusetsize, unsigned long __user *,
cpus, unsigned int, flags)
{
return do_riscv_hwprobe(pairs, pair_count, cpusetsize,
cpus, flags);
}

285
arch/riscv/kernel/sys_riscv.c
View File

@ -7,15 +7,7 @@
#include <linux/syscalls.h>
#include <asm/cacheflush.h>
#include <asm/cpufeature.h>
#include <asm/hwprobe.h>
#include <asm/sbi.h>
#include <asm/vector.h>
#include <asm/switch_to.h>
#include <asm/uaccess.h>
#include <asm/unistd.h>
#include <asm-generic/mman-common.h>
#include <vdso/vsyscall.h>
static long riscv_sys_mmap(unsigned long addr, unsigned long len,
unsigned long prot, unsigned long flags,
@ -77,283 +69,6 @@ SYSCALL_DEFINE3(riscv_flush_icache, uintptr_t, start, uintptr_t, end,
return 0;
}
/*
* The hwprobe interface, for allowing userspace to probe to see which features
* are supported by the hardware. See Documentation/arch/riscv/hwprobe.rst for more
* details.
*/
static void hwprobe_arch_id(struct riscv_hwprobe *pair,
const struct cpumask *cpus)
{
u64 id = -1ULL;
bool first = true;
int cpu;
for_each_cpu(cpu, cpus) {
u64 cpu_id;
switch (pair->key) {
case RISCV_HWPROBE_KEY_MVENDORID:
cpu_id = riscv_cached_mvendorid(cpu);
break;
case RISCV_HWPROBE_KEY_MIMPID:
cpu_id = riscv_cached_mimpid(cpu);
break;
case RISCV_HWPROBE_KEY_MARCHID:
cpu_id = riscv_cached_marchid(cpu);
break;
}
if (first) {
id = cpu_id;
first = false;
}
/*
* If there's a mismatch for the given set, return -1 in the
* value.
*/
if (id != cpu_id) {
id = -1ULL;
break;
}
}
pair->value = id;
}
static void hwprobe_isa_ext0(struct riscv_hwprobe *pair,
const struct cpumask *cpus)
{
int cpu;
u64 missing = 0;
pair->value = 0;
if (has_fpu())
pair->value |= RISCV_HWPROBE_IMA_FD;
if (riscv_isa_extension_available(NULL, c))
pair->value |= RISCV_HWPROBE_IMA_C;
if (has_vector())
pair->value |= RISCV_HWPROBE_IMA_V;
/*
* Loop through and record extensions that 1) anyone has, and 2) anyone
* doesn't have.
*/
for_each_cpu(cpu, cpus) {
struct riscv_isainfo *isainfo = &hart_isa[cpu];
#define EXT_KEY(ext) \
do { \
if (__riscv_isa_extension_available(isainfo->isa, RISCV_ISA_EXT_##ext)) \
pair->value |= RISCV_HWPROBE_EXT_##ext; \
else \
missing |= RISCV_HWPROBE_EXT_##ext; \
} while (false)
/*
* Only use EXT_KEY() for extensions which can be exposed to userspace,
* regardless of the kernel's configuration, as no other checks, besides
* presence in the hart_isa bitmap, are made.
*/
EXT_KEY(ZBA);
EXT_KEY(ZBB);
EXT_KEY(ZBS);
EXT_KEY(ZICBOZ);
#undef EXT_KEY
}
/* Now turn off reporting features if any CPU is missing it. */
pair->value &= ~missing;
}
static bool hwprobe_ext0_has(const struct cpumask *cpus, unsigned long ext)
{
struct riscv_hwprobe pair;
hwprobe_isa_ext0(&pair, cpus);
return (pair.value & ext);
}
static u64 hwprobe_misaligned(const struct cpumask *cpus)
{
int cpu;
u64 perf = -1ULL;
for_each_cpu(cpu, cpus) {
int this_perf = per_cpu(misaligned_access_speed, cpu);
if (perf == -1ULL)
perf = this_perf;
if (perf != this_perf) {
perf = RISCV_HWPROBE_MISALIGNED_UNKNOWN;
break;
}
}
if (perf == -1ULL)
return RISCV_HWPROBE_MISALIGNED_UNKNOWN;
return perf;
}
static void hwprobe_one_pair(struct riscv_hwprobe *pair,
const struct cpumask *cpus)
{
switch (pair->key) {
case RISCV_HWPROBE_KEY_MVENDORID:
case RISCV_HWPROBE_KEY_MARCHID:
case RISCV_HWPROBE_KEY_MIMPID:
hwprobe_arch_id(pair, cpus);
break;
/*
* The kernel already assumes that the base single-letter ISA
* extensions are supported on all harts, and only supports the
* IMA base, so just cheat a bit here and tell that to
* userspace.
*/
case RISCV_HWPROBE_KEY_BASE_BEHAVIOR:
pair->value = RISCV_HWPROBE_BASE_BEHAVIOR_IMA;
break;
case RISCV_HWPROBE_KEY_IMA_EXT_0:
hwprobe_isa_ext0(pair, cpus);
break;
case RISCV_HWPROBE_KEY_CPUPERF_0:
pair->value = hwprobe_misaligned(cpus);
break;
case RISCV_HWPROBE_KEY_ZICBOZ_BLOCK_SIZE:
pair->value = 0;
if (hwprobe_ext0_has(cpus, RISCV_HWPROBE_EXT_ZICBOZ))
pair->value = riscv_cboz_block_size;
break;
/*
* For forward compatibility, unknown keys don't fail the whole
* call, but get their element key set to -1 and value set to 0
* indicating they're unrecognized.
*/
default:
pair->key = -1;
pair->value = 0;
break;
}
}
static int do_riscv_hwprobe(struct riscv_hwprobe __user *pairs,
size_t pair_count, size_t cpusetsize,
unsigned long __user *cpus_user,
unsigned int flags)
{
size_t out;
int ret;
cpumask_t cpus;
/* Check the reserved flags. */
if (flags != 0)
return -EINVAL;
/*
* The interface supports taking in a CPU mask, and returns values that
* are consistent across that mask. Allow userspace to specify NULL and
* 0 as a shortcut to all online CPUs.
*/
cpumask_clear(&cpus);
if (!cpusetsize && !cpus_user) {
cpumask_copy(&cpus, cpu_online_mask);
} else {
if (cpusetsize > cpumask_size())
cpusetsize = cpumask_size();
ret = copy_from_user(&cpus, cpus_user, cpusetsize);
if (ret)
return -EFAULT;
/*
* Userspace must provide at least one online CPU, without that
* there's no way to define what is supported.
*/
cpumask_and(&cpus, &cpus, cpu_online_mask);
if (cpumask_empty(&cpus))
return -EINVAL;
}
for (out = 0; out < pair_count; out++, pairs++) {
struct riscv_hwprobe pair;
if (get_user(pair.key, &pairs->key))
return -EFAULT;
pair.value = 0;
hwprobe_one_pair(&pair, &cpus);
ret = put_user(pair.key, &pairs->key);
if (ret == 0)
ret = put_user(pair.value, &pairs->value);
if (ret)
return -EFAULT;
}
return 0;
}
#ifdef CONFIG_MMU
static int __init init_hwprobe_vdso_data(void)
{
struct vdso_data *vd = __arch_get_k_vdso_data();
struct arch_vdso_data *avd = &vd->arch_data;
u64 id_bitsmash = 0;
struct riscv_hwprobe pair;
int key;
/*
* Initialize vDSO data with the answers for the "all CPUs" case, to
* save a syscall in the common case.
*/
for (key = 0; key <= RISCV_HWPROBE_MAX_KEY; key++) {
pair.key = key;
hwprobe_one_pair(&pair, cpu_online_mask);
WARN_ON_ONCE(pair.key < 0);
avd->all_cpu_hwprobe_values[key] = pair.value;
/*
* Smash together the vendor, arch, and impl IDs to see if
* they're all 0 or any negative.
*/
if (key <= RISCV_HWPROBE_KEY_MIMPID)
id_bitsmash |= pair.value;
}
/*
* If the arch, vendor, and implementation ID are all the same across
* all harts, then assume all CPUs are the same, and allow the vDSO to
* answer queries for arbitrary masks. However if all values are 0 (not
* populated) or any value returns -1 (varies across CPUs), then the
* vDSO should defer to the kernel for exotic cpu masks.
*/
avd->homogeneous_cpus = id_bitsmash != 0 && id_bitsmash != -1;
return 0;
}
arch_initcall_sync(init_hwprobe_vdso_data);
#endif /* CONFIG_MMU */
SYSCALL_DEFINE5(riscv_hwprobe, struct riscv_hwprobe __user *, pairs,
size_t, pair_count, size_t, cpusetsize, unsigned long __user *,
cpus, unsigned int, flags)
{
return do_riscv_hwprobe(pairs, pair_count, cpusetsize,
cpus, flags);
}
/* Not defined using SYSCALL_DEFINE0 to avoid error injection */
asmlinkage long __riscv_sys_ni_syscall(const struct pt_regs *__unused)
{