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riscv: don't stop itself in smp_send_stop

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Add IPI_CPU_STOP message and use it in smp_send_stop to stop other cpus,
but not itself.  Mark cpu offline on reception of IPI_CPU_STOP.

Signed-off-by: Andreas Schwab <schwab@suse.de>
Reviewed-by: Atish Patra <atish.patra@wdc.com>
Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
This commit is contained in:
Andreas Schwab 2018-12-11 11:20:40 +01:00 committed by Palmer Dabbelt
parent 8fd6e05c74
commit 37a107ff6d
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GPG Key ID: EF4CA1502CCBAB41
1 changed files with 36 additions and 7 deletions
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43
arch/riscv/kernel/smp.c
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@ -23,6 +23,7 @@
#include <linux/smp.h>
#include <linux/sched.h>
#include <linux/seq_file.h>
#include <linux/delay.h>
#include <asm/sbi.h>
#include <asm/tlbflush.h>
@ -31,6 +32,7 @@
enum ipi_message_type {
IPI_RESCHEDULE,
IPI_CALL_FUNC,
IPI_CPU_STOP,
IPI_MAX
};
@ -66,6 +68,13 @@ 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();
}
void riscv_software_interrupt(void)
{
unsigned long *pending_ipis = &ipi_data[smp_processor_id()].bits;
@ -94,6 +103,11 @@ void riscv_software_interrupt(void)
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. */
@ -121,6 +135,7 @@ send_ipi_message(const struct cpumask *to_whom, enum ipi_message_type operation)
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)
@ -146,15 +161,29 @@ void arch_send_call_function_single_ipi(int cpu)
send_ipi_message(cpumask_of(cpu), IPI_CALL_FUNC);
}
static void ipi_stop(void *unused)
{
while (1)
wait_for_interrupt();
}
void smp_send_stop(void)
{
on_each_cpu(ipi_stop, NULL, 1);
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_message(&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)