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// SPDX-License-Identifier: GPL-2.0-only
/*
* SMP initialisation and IPI support
* Based on arch/arm64/kernel/smp.c
*
* Copyright (C) 2012 ARM Ltd.
* Copyright (C) 2015 Regents of the University of California
* Copyright (C) 2017 SiFive
*/
#include <linux/cpu.h>
#include <linux/interrupt.h>
#include <linux/profile.h>
#include <linux/smp.h>
#include <linux/sched.h>
#include <linux/seq_file.h>
#include <linux/delay.h>
#include <asm/clint.h>
#include <asm/sbi.h>
#include <asm/tlbflush.h>
#include <asm/cacheflush.h>
enum ipi_message_type {
IPI_RESCHEDULE,
IPI_CALL_FUNC,
IPI_CPU_STOP,
IPI_MAX
};
unsigned long __cpuid_to_hartid_map[NR_CPUS] = {
[0 ... NR_CPUS-1] = INVALID_HARTID
};
void __init smp_setup_processor_id(void)
{
cpuid_to_hartid_map(0) = boot_cpu_hartid;
}
/* A collection of single bit ipi messages. */
static struct {
unsigned long stats[IPI_MAX] ____cacheline_aligned;
unsigned long bits ____cacheline_aligned;
} ipi_data[NR_CPUS] __cacheline_aligned;
int riscv_hartid_to_cpuid(int hartid)
{
int i;
for (i = 0; i < NR_CPUS; i++)
if (cpuid_to_hartid_map(i) == hartid)
return i;
pr_err("Couldn't find cpu id for hartid [%d]\n", hartid);
return i;
}
void riscv_cpuid_to_hartid_mask(const struct cpumask *in, struct cpumask *out)
{
int cpu;
cpumask_clear(out);
for_each_cpu(cpu, in)
cpumask_set_cpu(cpuid_to_hartid_map(cpu), out);
}
bool arch_match_cpu_phys_id(int cpu, u64 phys_id)
{
return phys_id == cpuid_to_hartid_map(cpu);
}
/* Unsupported */
int setup_profiling_timer(unsigned int multiplier)
{
return -EINVAL;
}
static void ipi_stop(void)
{
set_cpu_online(smp_processor_id(), false);
while (1)
wait_for_interrupt();
}
static void send_ipi_mask(const struct cpumask *mask, enum ipi_message_type op)
{
struct cpumask hartid_mask;
int cpu;
smp_mb__before_atomic();
for_each_cpu(cpu, mask)
set_bit(op, &ipi_data[cpu].bits);
smp_mb__after_atomic();
riscv_cpuid_to_hartid_mask(mask, &hartid_mask);
if (IS_ENABLED(CONFIG_RISCV_SBI))
sbi_send_ipi(cpumask_bits(&hartid_mask));
else
clint_send_ipi_mask(&hartid_mask);
}
static void send_ipi_single(int cpu, enum ipi_message_type op)
{
int hartid = cpuid_to_hartid_map(cpu);
smp_mb__before_atomic();
set_bit(op, &ipi_data[cpu].bits);
smp_mb__after_atomic();
if (IS_ENABLED(CONFIG_RISCV_SBI))
sbi_send_ipi(cpumask_bits(cpumask_of(hartid)));
else
clint_send_ipi_single(hartid);
}
static inline void clear_ipi(void)
{
if (IS_ENABLED(CONFIG_RISCV_SBI))
csr_clear(CSR_IP, IE_SIE);
else
clint_clear_ipi(cpuid_to_hartid_map(smp_processor_id()));
}
void riscv_software_interrupt(void)
{
unsigned long *pending_ipis = &ipi_data[smp_processor_id()].bits;
unsigned long *stats = ipi_data[smp_processor_id()].stats;
clear_ipi();
while (true) {
unsigned long ops;
/* Order bit clearing and data access. */
mb();
ops = xchg(pending_ipis, 0);
if (ops == 0)
return;
if (ops & (1 << IPI_RESCHEDULE)) {
stats[IPI_RESCHEDULE]++;
scheduler_ipi();
}
if (ops & (1 << IPI_CALL_FUNC)) {
stats[IPI_CALL_FUNC]++;
generic_smp_call_function_interrupt();
}
if (ops & (1 << IPI_CPU_STOP)) {
stats[IPI_CPU_STOP]++;
ipi_stop();
}
BUG_ON((ops >> IPI_MAX) != 0);
/* Order data access and bit testing. */
mb();
}
}
static const char * const ipi_names[] = {
[IPI_RESCHEDULE] = "Rescheduling interrupts",
[IPI_CALL_FUNC] = "Function call interrupts",
[IPI_CPU_STOP] = "CPU stop interrupts",
};
void show_ipi_stats(struct seq_file *p, int prec)
{
unsigned int cpu, i;
for (i = 0; i < IPI_MAX; i++) {
seq_printf(p, "%*s%u:%s", prec - 1, "IPI", i,
prec >= 4 ? " " : "");
for_each_online_cpu(cpu)
seq_printf(p, "%10lu ", ipi_data[cpu].stats[i]);
seq_printf(p, " %s\n", ipi_names[i]);
}
}
void arch_send_call_function_ipi_mask(struct cpumask *mask)
{
send_ipi_mask(mask, IPI_CALL_FUNC);
}
void arch_send_call_function_single_ipi(int cpu)
{
send_ipi_single(cpu, IPI_CALL_FUNC);
}
void smp_send_stop(void)
{
unsigned long timeout;
if (num_online_cpus() > 1) {
cpumask_t mask;
cpumask_copy(&mask, cpu_online_mask);
cpumask_clear_cpu(smp_processor_id(), &mask);
if (system_state <= SYSTEM_RUNNING)
pr_crit("SMP: stopping secondary CPUs\n");
send_ipi_mask(&mask, IPI_CPU_STOP);
}
/* Wait up to one second for other CPUs to stop */
timeout = USEC_PER_SEC;
while (num_online_cpus() > 1 && timeout--)
udelay(1);
if (num_online_cpus() > 1)
pr_warn("SMP: failed to stop secondary CPUs %*pbl\n",
cpumask_pr_args(cpu_online_mask));
}
void smp_send_reschedule(int cpu)
{
send_ipi_single(cpu, IPI_RESCHEDULE);
}
EXPORT_SYMBOL_GPL(smp_send_reschedule);
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