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xtensa: implement CPU hotplug

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Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: Chris Zankel <chris@zankel.net>
This commit is contained in:
Max Filippov
2013-10-17 02:42:28 +04:00
committed by Chris Zankel
parent f615136c06
commit 49b424feda
8 changed files with 248 additions and 4 deletions
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128
arch/xtensa/kernel/smp.c
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@@ -40,6 +40,11 @@
# endif
#endif
static void system_invalidate_dcache_range(unsigned long start,
unsigned long size);
static void system_flush_invalidate_dcache_range(unsigned long start,
unsigned long size);
/* IPI (Inter Process Interrupt) */
#define IPI_IRQ 0
@@ -106,7 +111,7 @@ void __init smp_cpus_done(unsigned int max_cpus)
static int boot_secondary_processors = 1; /* Set with xt-gdb via .xt-gdb */
static DECLARE_COMPLETION(cpu_running);
void __init secondary_start_kernel(void)
void secondary_start_kernel(void)
{
struct mm_struct *mm = &init_mm;
unsigned int cpu = smp_processor_id();
@@ -174,6 +179,9 @@ static void mx_cpu_stop(void *p)
__func__, cpu, run_stall_mask, get_er(MPSCORE));
}
#ifdef CONFIG_HOTPLUG_CPU
unsigned long cpu_start_id __cacheline_aligned;
#endif
unsigned long cpu_start_ccount;
static int boot_secondary(unsigned int cpu, struct task_struct *ts)
@@ -182,6 +190,11 @@ static int boot_secondary(unsigned int cpu, struct task_struct *ts)
unsigned long ccount;
int i;
#ifdef CONFIG_HOTPLUG_CPU
cpu_start_id = cpu;
system_flush_invalidate_dcache_range(
(unsigned long)&cpu_start_id, sizeof(cpu_start_id));
#endif
smp_call_function_single(0, mx_cpu_start, (void *)cpu, 1);
for (i = 0; i < 2; ++i) {
@@ -234,6 +247,85 @@ int __cpu_up(unsigned int cpu, struct task_struct *idle)
return ret;
}
#ifdef CONFIG_HOTPLUG_CPU
/*
* __cpu_disable runs on the processor to be shutdown.
*/
int __cpu_disable(void)
{
unsigned int cpu = smp_processor_id();
/*
* Take this CPU offline. Once we clear this, we can't return,
* and we must not schedule until we're ready to give up the cpu.
*/
set_cpu_online(cpu, false);
/*
* OK - migrate IRQs away from this CPU
*/
migrate_irqs();
/*
* Flush user cache and TLB mappings, and then remove this CPU
* from the vm mask set of all processes.
*/
local_flush_cache_all();
local_flush_tlb_all();
invalidate_page_directory();
clear_tasks_mm_cpumask(cpu);
return 0;
}
static void platform_cpu_kill(unsigned int cpu)
{
smp_call_function_single(0, mx_cpu_stop, (void *)cpu, true);
}
/*
* called on the thread which is asking for a CPU to be shutdown -
* waits until shutdown has completed, or it is timed out.
*/
void __cpu_die(unsigned int cpu)
{
unsigned long timeout = jiffies + msecs_to_jiffies(1000);
while (time_before(jiffies, timeout)) {
system_invalidate_dcache_range((unsigned long)&cpu_start_id,
sizeof(cpu_start_id));
if (cpu_start_id == -cpu) {
platform_cpu_kill(cpu);
return;
}
}
pr_err("CPU%u: unable to kill\n", cpu);
}
void arch_cpu_idle_dead(void)
{
cpu_die();
}
/*
* Called from the idle thread for the CPU which has been shutdown.
*
* Note that we disable IRQs here, but do not re-enable them
* before returning to the caller. This is also the behaviour
* of the other hotplug-cpu capable cores, so presumably coming
* out of idle fixes this.
*/
void __ref cpu_die(void)
{
idle_task_exit();
local_irq_disable();
__asm__ __volatile__(
" movi a2, cpu_restart\n"
" jx a2\n");
}
#endif /* CONFIG_HOTPLUG_CPU */
enum ipi_msg_type {
IPI_RESCHEDULE = 0,
IPI_CALL_FUNC,
@@ -463,3 +555,37 @@ void flush_icache_range(unsigned long start, unsigned long end)
};
on_each_cpu(ipi_flush_icache_range, &fd, 1);
}
/* ------------------------------------------------------------------------- */
static void ipi_invalidate_dcache_range(void *arg)
{
struct flush_data *fd = arg;
__invalidate_dcache_range(fd->addr1, fd->addr2);
}
static void system_invalidate_dcache_range(unsigned long start,
unsigned long size)
{
struct flush_data fd = {
.addr1 = start,
.addr2 = size,
};
on_each_cpu(ipi_invalidate_dcache_range, &fd, 1);
}
static void ipi_flush_invalidate_dcache_range(void *arg)
{
struct flush_data *fd = arg;
__flush_invalidate_dcache_range(fd->addr1, fd->addr2);
}
static void system_flush_invalidate_dcache_range(unsigned long start,
unsigned long size)
{
struct flush_data fd = {
.addr1 = start,
.addr2 = size,
};
on_each_cpu(ipi_flush_invalidate_dcache_range, &fd, 1);
}