summaryrefslogtreecommitdiffstats
path: root/arch/xtensa/kernel/smp.c
diff options
context:
space:
mode:
Diffstat (limited to 'arch/xtensa/kernel/smp.c')
-rw-r--r--arch/xtensa/kernel/smp.c634
1 files changed, 634 insertions, 0 deletions
diff --git a/arch/xtensa/kernel/smp.c b/arch/xtensa/kernel/smp.c
new file mode 100644
index 000000000..4dc109dd6
--- /dev/null
+++ b/arch/xtensa/kernel/smp.c
@@ -0,0 +1,634 @@
+/*
+ * 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 <chris@zankel.net>
+ * Joe Taylor <joe@tensilica.com>
+ * Pete Delaney <piet@tensilica.com
+ */
+
+#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/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 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,
+ 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 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);
+}