/*
* Xtensa SMP support functions.
*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*
* Copyright (C) 2008 - 2013 Tensilica Inc.
*
* Chris Zankel <[email protected]>
* Joe Taylor <[email protected]>
* Pete Delaney <[email protected]
*/
#include <linux/cpu.h>
#include <linux/cpumask.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/irqdomain.h>
#include <linux/irq.h>
#include <linux/kdebug.h>
#include <linux/module.h>
#include <linux/profile.h>
#include <linux/sched/mm.h>
#include <linux/sched/hotplug.h>
#include <linux/sched/task_stack.h>
#include <linux/reboot.h>
#include <linux/seq_file.h>
#include <linux/smp.h>
#include <linux/thread_info.h>
#include <asm/cacheflush.h>
#include <asm/coprocessor.h>
#include <asm/kdebug.h>
#include <asm/mmu_context.h>
#include <asm/mxregs.h>
#include <asm/platform.h>
#include <asm/tlbflush.h>
#include <asm/traps.h>
#ifdef CONFIG_SMP
# if XCHAL_HAVE_S32C1I == 0
# error "The S32C1I option is required for SMP."
# 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
static irqreturn_t ipi_interrupt(int irq, void *dev_id);
void ipi_init(void)
{
unsigned irq = irq_create_mapping(NULL, IPI_IRQ);
if (request_irq(irq, ipi_interrupt, IRQF_PERCPU, "ipi", NULL))
pr_err("Failed to request irq %u (ipi)\n", irq);
}
static inline unsigned int get_core_count(void)
{
/* Bits 18..21 of SYSCFGID contain the core count minus 1. */
unsigned int syscfgid = get_er(SYSCFGID);
return ((syscfgid >> 18) & 0xf) + 1;
}
static inline int get_core_id(void)
{
/* Bits 0...18 of SYSCFGID contain the core id */
unsigned int core_id = get_er(SYSCFGID);
return core_id & 0x3fff;
}
void __init smp_prepare_cpus(unsigned int max_cpus)
{
unsigned i;
for_each_possible_cpu(i)
set_cpu_present(i, true);
}
void __init smp_init_cpus(void)
{
unsigned i;
unsigned int ncpus = get_core_count();
unsigned int core_id = get_core_id();
pr_info("%s: Core Count = %d\n", __func__, ncpus);
pr_info("%s: Core Id = %d\n", __func__, core_id);
if (ncpus > NR_CPUS) {
ncpus = NR_CPUS;
pr_info("%s: limiting core count by %d\n", __func__, ncpus);
}
for (i = 0; i < ncpus; ++i)
set_cpu_possible(i, true);
}
void __init smp_prepare_boot_cpu(void)
{
unsigned int cpu = smp_processor_id();
BUG_ON(cpu != 0);
cpu_asid_cache(cpu) = ASID_USER_FIRST;
}
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 secondary_start_kernel(void)
{
struct mm_struct *mm = &init_mm;
unsigned int cpu = smp_processor_id();
init_mmu();
#ifdef CONFIG_DEBUG_MISC
if (boot_secondary_processors == 0) {
pr_debug("%s: boot_secondary_processors:%d; Hanging cpu:%d\n",
__func__, boot_secondary_processors, cpu);
for (;;)
__asm__ __volatile__ ("waiti " __stringify(LOCKLEVEL));
}
pr_debug("%s: boot_secondary_processors:%d; Booting cpu:%d\n",
__func__, boot_secondary_processors, cpu);
#endif
/* Init EXCSAVE1 */
secondary_trap_init();
/* All kernel threads share the same mm context. */
mmget(mm);
mmgrab(mm);
current->active_mm = mm;
cpumask_set_cpu(cpu, mm_cpumask(mm));
enter_lazy_tlb(mm, current);
trace_hardirqs_off();
calibrate_delay();
notify_cpu_starting(cpu);
secondary_init_irq();
local_timer_setup(cpu);
set_cpu_online(cpu, true);
local_irq_enable();
complete(&cpu_running);
cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
}
static void mx_cpu_start(void *p)
{
unsigned cpu = (unsigned)p;
unsigned long run_stall_mask = get_er(MPSCORE);
set_er(run_stall_mask & ~(1u << cpu), MPSCORE);
pr_debug("%s: cpu: %d, run_stall_mask: %lx ---> %lx\n",
__func__, cpu, run_stall_mask, get_er(MPSCORE));
}
static void mx_cpu_stop(void *p)
{
unsigned cpu = (unsigned)p;
unsigned long run_stall_mask = get_er(MPSCORE);
set_er(run_stall_mask | (1u << cpu), MPSCORE);
pr_debug("%s: cpu: %d, run_stall_mask: %lx ---> %lx\n",
__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)
{
unsigned long timeout = jiffies + msecs_to_jiffies(1000);
unsigned long ccount;
int i;
#ifdef CONFIG_HOTPLUG_CPU
WRITE_ONCE(cpu_start_id, cpu);
/* Pairs with the third memw in the cpu_restart */
mb();
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) {
do
ccount = get_ccount();
while (!ccount);
WRITE_ONCE(cpu_start_ccount, ccount);
do {
/*
* Pairs with the first two memws in the
* .Lboot_secondary.
*/
mb();
ccount = READ_ONCE(cpu_start_ccount);
} while (ccount && time_before(jiffies, timeout));
if (ccount) {
smp_call_function_single(0, mx_cpu_stop,
(void *)cpu, 1);
WRITE_ONCE(cpu_start_ccount, 0);
return -EIO;
}
}
return 0;
}
int __cpu_up(unsigned int cpu, struct task_struct *idle)
{
int ret = 0;
if (cpu_asid_cache(cpu) == 0)
cpu_asid_cache(cpu) = ASID_USER_FIRST;
start_info.stack = (unsigned long)task_pt_regs(idle);
wmb();
pr_debug("%s: Calling wakeup_secondary(cpu:%d, idle:%p, sp: %08lx)\n",
__func__, cpu, idle, start_info.stack);
init_completion(&cpu_running);
ret = boot_secondary(cpu, idle);
if (ret == 0) {
wait_for_completion_timeout(&cpu_running,
msecs_to_jiffies(1000));
if (!cpu_online(cpu))
ret = -EIO;
}
if (ret)
pr_err("CPU %u failed to boot\n", cpu);
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);
#if XTENSA_HAVE_COPROCESSORS
/*
* Flush coprocessor contexts that are active on the current CPU.
*/
local_coprocessors_flush_release_all();
#endif
/*
* 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));
/* Pairs with the second memw in the cpu_restart */
mb();
if (READ_ONCE(cpu_start_id) == -cpu) {
platform_cpu_kill(cpu);
return;
}
}
pr_err("CPU%u: unable to kill\n", cpu);
}
void __noreturn 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");
BUG();
}
#endif /* CONFIG_HOTPLUG_CPU */
enum ipi_msg_type {
IPI_RESCHEDULE = 0,
IPI_CALL_FUNC,
IPI_CPU_STOP,
IPI_MAX
};
static const struct {
const char *short_text;
const char *long_text;
} ipi_text[] = {
{ .short_text = "RES", .long_text = "Rescheduling interrupts" },
{ .short_text = "CAL", .long_text = "Function call interrupts" },
{ .short_text = "DIE", .long_text = "CPU shutdown interrupts" },
};
struct ipi_data {
unsigned long ipi_count[IPI_MAX];
};
static DEFINE_PER_CPU(struct ipi_data, ipi_data);
static void send_ipi_message(const struct cpumask *callmask,
enum ipi_msg_type msg_id)
{
int index;
unsigned long mask = 0;
for_each_cpu(index, callmask)
mask |= 1 << index;
set_er(mask, MIPISET(msg_id));
}
void arch_send_call_function_ipi_mask(const struct cpumask *mask)
{
send_ipi_message(mask, IPI_CALL_FUNC);
}
void arch_send_call_function_single_ipi(int cpu)
{
send_ipi_message(cpumask_of(cpu), IPI_CALL_FUNC);
}
void arch_smp_send_reschedule(int cpu)
{
send_ipi_message(cpumask_of(cpu), IPI_RESCHEDULE);
}
void smp_send_stop(void)
{
struct cpumask targets;
cpumask_copy(&targets, cpu_online_mask);
cpumask_clear_cpu(smp_processor_id(), &targets);
send_ipi_message(&targets, IPI_CPU_STOP);
}
static void ipi_cpu_stop(unsigned int cpu)
{
set_cpu_online(cpu, false);
machine_halt();
}
irqreturn_t ipi_interrupt(int irq, void *dev_id)
{
unsigned int cpu = smp_processor_id();
struct ipi_data *ipi = &per_cpu(ipi_data, cpu);
for (;;) {
unsigned int msg;
msg = get_er(MIPICAUSE(cpu));
set_er(msg, MIPICAUSE(cpu));
if (!msg)
break;
if (msg & (1 << IPI_CALL_FUNC)) {
++ipi->ipi_count[IPI_CALL_FUNC];
generic_smp_call_function_interrupt();
}
if (msg & (1 << IPI_RESCHEDULE)) {
++ipi->ipi_count[IPI_RESCHEDULE];
scheduler_ipi();
}
if (msg & (1 << IPI_CPU_STOP)) {
++ipi->ipi_count[IPI_CPU_STOP];
ipi_cpu_stop(cpu);
}
}
return IRQ_HANDLED;
}
void show_ipi_list(struct seq_file *p, int prec)
{
unsigned int cpu;
unsigned i;
for (i = 0; i < IPI_MAX; ++i) {
seq_printf(p, "%*s:", prec, ipi_text[i].short_text);
for_each_online_cpu(cpu)
seq_printf(p, " %10lu",
per_cpu(ipi_data, cpu).ipi_count[i]);
seq_printf(p, " %s\n", ipi_text[i].long_text);
}
}
int setup_profiling_timer(unsigned int multiplier)
{
pr_debug("setup_profiling_timer %d\n", multiplier);
return 0;
}
/* TLB flush functions */
struct flush_data {
struct vm_area_struct *vma;
unsigned long addr1;
unsigned long addr2;
};
static void ipi_flush_tlb_all(void *arg)
{
local_flush_tlb_all();
}
void flush_tlb_all(void)
{
on_each_cpu(ipi_flush_tlb_all, NULL, 1);
}
static void ipi_flush_tlb_mm(void *arg)
{
local_flush_tlb_mm(arg);
}
void flush_tlb_mm(struct mm_struct *mm)
{
on_each_cpu(ipi_flush_tlb_mm, mm, 1);
}
static void ipi_flush_tlb_page(void *arg)
{
struct flush_data *fd = arg;
local_flush_tlb_page(fd->vma, fd->addr1);
}
void flush_tlb_page(struct vm_area_struct *vma, unsigned long addr)
{
struct flush_data fd = {
.vma = vma,
.addr1 = addr,
};
on_each_cpu(ipi_flush_tlb_page, &fd, 1);
}
static void ipi_flush_tlb_range(void *arg)
{
struct flush_data *fd = arg;
local_flush_tlb_range(fd->vma, fd->addr1, fd->addr2);
}
void flush_tlb_range(struct vm_area_struct *vma,
unsigned long start, unsigned long end)
{
struct flush_data fd = {
.vma = vma,
.addr1 = start,
.addr2 = end,
};
on_each_cpu(ipi_flush_tlb_range, &fd, 1);
}
static void ipi_flush_tlb_kernel_range(void *arg)
{
struct flush_data *fd = arg;
local_flush_tlb_kernel_range(fd->addr1, fd->addr2);
}
void flush_tlb_kernel_range(unsigned long start, unsigned long end)
{
struct flush_data fd = {
.addr1 = start,
.addr2 = end,
};
on_each_cpu(ipi_flush_tlb_kernel_range, &fd, 1);
}
/* Cache flush functions */
static void ipi_flush_cache_all(void *arg)
{
local_flush_cache_all();
}
void flush_cache_all(void)
{
on_each_cpu(ipi_flush_cache_all, NULL, 1);
}
static void ipi_flush_cache_page(void *arg)
{
struct flush_data *fd = arg;
local_flush_cache_page(fd->vma, fd->addr1, fd->addr2);
}
void flush_cache_page(struct vm_area_struct *vma,
unsigned long address, unsigned long pfn)
{
struct flush_data fd = {
.vma = vma,
.addr1 = address,
.addr2 = pfn,
};
on_each_cpu(ipi_flush_cache_page, &fd, 1);
}
static void ipi_flush_cache_range(void *arg)
{
struct flush_data *fd = arg;
local_flush_cache_range(fd->vma, fd->addr1, fd->addr2);
}
void flush_cache_range(struct vm_area_struct *vma,
unsigned long start, unsigned long end)
{
struct flush_data fd = {
.vma = vma,
.addr1 = start,
.addr2 = end,
};
on_each_cpu(ipi_flush_cache_range, &fd, 1);
}
static void ipi_flush_icache_range(void *arg)
{
struct flush_data *fd = arg;
local_flush_icache_range(fd->addr1, fd->addr2);
}
void flush_icache_range(unsigned long start, unsigned long end)
{
struct flush_data fd = {
.addr1 = start,
.addr2 = end,
};
on_each_cpu(ipi_flush_icache_range, &fd, 1);
}
EXPORT_SYMBOL(flush_icache_range);
/* ------------------------------------------------------------------------- */
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);
}
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