e178bf146e
Introduce the first flag for the hwprobe syscall. The flag basically reverses its behavior, i.e. instead of populating the values of keys for a given set of cpus, the set of cpus after the call is the result of finding a set which supports the values of the keys. In order to do this, we implement a pair compare function which takes the type of value (a single value vs. a bitmask of booleans) into consideration. We also implement vdso support for the new flag. Signed-off-by: Andrew Jones <ajones@ventanamicro.com> Reviewed-by: Evan Green <evan@rivosinc.com> Link: https://lore.kernel.org/r/20231122164700.127954-9-ajones@ventanamicro.com Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
117 lines
2.9 KiB
C
117 lines
2.9 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright 2023 Rivos, Inc
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*/
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#include <linux/string.h>
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#include <linux/types.h>
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#include <vdso/datapage.h>
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#include <vdso/helpers.h>
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extern int riscv_hwprobe(struct riscv_hwprobe *pairs, size_t pair_count,
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size_t cpusetsize, unsigned long *cpus,
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unsigned int flags);
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static int riscv_vdso_get_values(struct riscv_hwprobe *pairs, size_t pair_count,
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size_t cpusetsize, unsigned long *cpus,
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unsigned int flags)
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{
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const struct vdso_data *vd = __arch_get_vdso_data();
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const struct arch_vdso_data *avd = &vd->arch_data;
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bool all_cpus = !cpusetsize && !cpus;
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struct riscv_hwprobe *p = pairs;
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struct riscv_hwprobe *end = pairs + pair_count;
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/*
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* Defer to the syscall for exotic requests. The vdso has answers
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* stashed away only for the "all cpus" case. If all CPUs are
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* homogeneous, then this function can handle requests for arbitrary
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* masks.
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*/
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if ((flags != 0) || (!all_cpus && !avd->homogeneous_cpus))
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return riscv_hwprobe(pairs, pair_count, cpusetsize, cpus, flags);
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/* This is something we can handle, fill out the pairs. */
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while (p < end) {
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if (riscv_hwprobe_key_is_valid(p->key)) {
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p->value = avd->all_cpu_hwprobe_values[p->key];
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} else {
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p->key = -1;
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p->value = 0;
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}
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p++;
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}
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return 0;
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}
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static int riscv_vdso_get_cpus(struct riscv_hwprobe *pairs, size_t pair_count,
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size_t cpusetsize, unsigned long *cpus,
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unsigned int flags)
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{
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const struct vdso_data *vd = __arch_get_vdso_data();
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const struct arch_vdso_data *avd = &vd->arch_data;
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struct riscv_hwprobe *p = pairs;
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struct riscv_hwprobe *end = pairs + pair_count;
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unsigned char *c = (unsigned char *)cpus;
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bool empty_cpus = true;
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bool clear_all = false;
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int i;
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if (!cpusetsize || !cpus)
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return -EINVAL;
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for (i = 0; i < cpusetsize; i++) {
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if (c[i]) {
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empty_cpus = false;
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break;
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}
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}
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if (empty_cpus || flags != RISCV_HWPROBE_WHICH_CPUS || !avd->homogeneous_cpus)
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return riscv_hwprobe(pairs, pair_count, cpusetsize, cpus, flags);
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while (p < end) {
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if (riscv_hwprobe_key_is_valid(p->key)) {
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struct riscv_hwprobe t = {
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.key = p->key,
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.value = avd->all_cpu_hwprobe_values[p->key],
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};
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if (!riscv_hwprobe_pair_cmp(&t, p))
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clear_all = true;
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} else {
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clear_all = true;
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p->key = -1;
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p->value = 0;
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}
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p++;
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}
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if (clear_all) {
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for (i = 0; i < cpusetsize; i++)
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c[i] = 0;
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}
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return 0;
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}
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/* Add a prototype to avoid -Wmissing-prototypes warning. */
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int __vdso_riscv_hwprobe(struct riscv_hwprobe *pairs, size_t pair_count,
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size_t cpusetsize, unsigned long *cpus,
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unsigned int flags);
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int __vdso_riscv_hwprobe(struct riscv_hwprobe *pairs, size_t pair_count,
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size_t cpusetsize, unsigned long *cpus,
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unsigned int flags)
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{
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if (flags & RISCV_HWPROBE_WHICH_CPUS)
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return riscv_vdso_get_cpus(pairs, pair_count, cpusetsize,
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cpus, flags);
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return riscv_vdso_get_values(pairs, pair_count, cpusetsize,
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cpus, flags);
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}
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