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authorAndré Fabian Silva Delgado <emulatorman@parabola.nu>2015-08-05 17:04:01 -0300
committerAndré Fabian Silva Delgado <emulatorman@parabola.nu>2015-08-05 17:04:01 -0300
commit57f0f512b273f60d52568b8c6b77e17f5636edc0 (patch)
tree5e910f0e82173f4ef4f51111366a3f1299037a7b /arch/powerpc/platforms/pseries/smp.c
Initial import
Diffstat (limited to 'arch/powerpc/platforms/pseries/smp.c')
-rw-r--r--arch/powerpc/platforms/pseries/smp.c274
1 files changed, 274 insertions, 0 deletions
diff --git a/arch/powerpc/platforms/pseries/smp.c b/arch/powerpc/platforms/pseries/smp.c
new file mode 100644
index 000000000..6932ea803
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+++ b/arch/powerpc/platforms/pseries/smp.c
@@ -0,0 +1,274 @@
+/*
+ * SMP support for pSeries machines.
+ *
+ * Dave Engebretsen, Peter Bergner, and
+ * Mike Corrigan {engebret|bergner|mikec}@us.ibm.com
+ *
+ * Plus various changes from other IBM teams...
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/smp.h>
+#include <linux/interrupt.h>
+#include <linux/delay.h>
+#include <linux/init.h>
+#include <linux/spinlock.h>
+#include <linux/cache.h>
+#include <linux/err.h>
+#include <linux/device.h>
+#include <linux/cpu.h>
+
+#include <asm/ptrace.h>
+#include <linux/atomic.h>
+#include <asm/irq.h>
+#include <asm/page.h>
+#include <asm/pgtable.h>
+#include <asm/io.h>
+#include <asm/prom.h>
+#include <asm/smp.h>
+#include <asm/paca.h>
+#include <asm/machdep.h>
+#include <asm/cputable.h>
+#include <asm/firmware.h>
+#include <asm/rtas.h>
+#include <asm/mpic.h>
+#include <asm/vdso_datapage.h>
+#include <asm/cputhreads.h>
+#include <asm/xics.h>
+#include <asm/dbell.h>
+#include <asm/plpar_wrappers.h>
+#include <asm/code-patching.h>
+
+#include "pseries.h"
+#include "offline_states.h"
+
+
+/*
+ * The Primary thread of each non-boot processor was started from the OF client
+ * interface by prom_hold_cpus and is spinning on secondary_hold_spinloop.
+ */
+static cpumask_var_t of_spin_mask;
+
+/*
+ * If we multiplex IPI mechanisms, store the appropriate XICS IPI mechanism here
+ */
+static void (*xics_cause_ipi)(int cpu, unsigned long data);
+
+/* Query where a cpu is now. Return codes #defined in plpar_wrappers.h */
+int smp_query_cpu_stopped(unsigned int pcpu)
+{
+ int cpu_status, status;
+ int qcss_tok = rtas_token("query-cpu-stopped-state");
+
+ if (qcss_tok == RTAS_UNKNOWN_SERVICE) {
+ printk_once(KERN_INFO
+ "Firmware doesn't support query-cpu-stopped-state\n");
+ return QCSS_HARDWARE_ERROR;
+ }
+
+ status = rtas_call(qcss_tok, 1, 2, &cpu_status, pcpu);
+ if (status != 0) {
+ printk(KERN_ERR
+ "RTAS query-cpu-stopped-state failed: %i\n", status);
+ return status;
+ }
+
+ return cpu_status;
+}
+
+/**
+ * smp_startup_cpu() - start the given cpu
+ *
+ * At boot time, there is nothing to do for primary threads which were
+ * started from Open Firmware. For anything else, call RTAS with the
+ * appropriate start location.
+ *
+ * Returns:
+ * 0 - failure
+ * 1 - success
+ */
+static inline int smp_startup_cpu(unsigned int lcpu)
+{
+ int status;
+ unsigned long start_here =
+ __pa(ppc_function_entry(generic_secondary_smp_init));
+ unsigned int pcpu;
+ int start_cpu;
+
+ if (cpumask_test_cpu(lcpu, of_spin_mask))
+ /* Already started by OF and sitting in spin loop */
+ return 1;
+
+ pcpu = get_hard_smp_processor_id(lcpu);
+
+ /* Check to see if the CPU out of FW already for kexec */
+ if (smp_query_cpu_stopped(pcpu) == QCSS_NOT_STOPPED){
+ cpumask_set_cpu(lcpu, of_spin_mask);
+ return 1;
+ }
+
+ /* Fixup atomic count: it exited inside IRQ handler. */
+ task_thread_info(paca[lcpu].__current)->preempt_count = 0;
+#ifdef CONFIG_HOTPLUG_CPU
+ if (get_cpu_current_state(lcpu) == CPU_STATE_INACTIVE)
+ goto out;
+#endif
+ /*
+ * If the RTAS start-cpu token does not exist then presume the
+ * cpu is already spinning.
+ */
+ start_cpu = rtas_token("start-cpu");
+ if (start_cpu == RTAS_UNKNOWN_SERVICE)
+ return 1;
+
+ status = rtas_call(start_cpu, 3, 1, NULL, pcpu, start_here, pcpu);
+ if (status != 0) {
+ printk(KERN_ERR "start-cpu failed: %i\n", status);
+ return 0;
+ }
+
+#ifdef CONFIG_HOTPLUG_CPU
+out:
+#endif
+ return 1;
+}
+
+static void smp_xics_setup_cpu(int cpu)
+{
+ if (cpu != boot_cpuid)
+ xics_setup_cpu();
+ if (cpu_has_feature(CPU_FTR_DBELL))
+ doorbell_setup_this_cpu();
+
+ if (firmware_has_feature(FW_FEATURE_SPLPAR))
+ vpa_init(cpu);
+
+ cpumask_clear_cpu(cpu, of_spin_mask);
+#ifdef CONFIG_HOTPLUG_CPU
+ set_cpu_current_state(cpu, CPU_STATE_ONLINE);
+ set_default_offline_state(cpu);
+#endif
+}
+
+static int smp_pSeries_kick_cpu(int nr)
+{
+ BUG_ON(nr < 0 || nr >= NR_CPUS);
+
+ if (!smp_startup_cpu(nr))
+ return -ENOENT;
+
+ /*
+ * The processor is currently spinning, waiting for the
+ * cpu_start field to become non-zero After we set cpu_start,
+ * the processor will continue on to secondary_start
+ */
+ paca[nr].cpu_start = 1;
+#ifdef CONFIG_HOTPLUG_CPU
+ set_preferred_offline_state(nr, CPU_STATE_ONLINE);
+
+ if (get_cpu_current_state(nr) == CPU_STATE_INACTIVE) {
+ long rc;
+ unsigned long hcpuid;
+
+ hcpuid = get_hard_smp_processor_id(nr);
+ rc = plpar_hcall_norets(H_PROD, hcpuid);
+ if (rc != H_SUCCESS)
+ printk(KERN_ERR "Error: Prod to wake up processor %d "
+ "Ret= %ld\n", nr, rc);
+ }
+#endif
+
+ return 0;
+}
+
+/* Only used on systems that support multiple IPI mechanisms */
+static void pSeries_cause_ipi_mux(int cpu, unsigned long data)
+{
+ if (cpumask_test_cpu(cpu, cpu_sibling_mask(smp_processor_id())))
+ doorbell_cause_ipi(cpu, data);
+ else
+ xics_cause_ipi(cpu, data);
+}
+
+static __init void pSeries_smp_probe(void)
+{
+ xics_smp_probe();
+
+ if (cpu_has_feature(CPU_FTR_DBELL)) {
+ xics_cause_ipi = smp_ops->cause_ipi;
+ smp_ops->cause_ipi = pSeries_cause_ipi_mux;
+ }
+}
+
+static struct smp_ops_t pSeries_mpic_smp_ops = {
+ .message_pass = smp_mpic_message_pass,
+ .probe = smp_mpic_probe,
+ .kick_cpu = smp_pSeries_kick_cpu,
+ .setup_cpu = smp_mpic_setup_cpu,
+};
+
+static struct smp_ops_t pSeries_xics_smp_ops = {
+ .message_pass = NULL, /* Use smp_muxed_ipi_message_pass */
+ .cause_ipi = NULL, /* Filled at runtime by pSeries_smp_probe() */
+ .probe = pSeries_smp_probe,
+ .kick_cpu = smp_pSeries_kick_cpu,
+ .setup_cpu = smp_xics_setup_cpu,
+ .cpu_bootable = smp_generic_cpu_bootable,
+};
+
+/* This is called very early */
+static void __init smp_init_pseries(void)
+{
+ int i;
+
+ pr_debug(" -> smp_init_pSeries()\n");
+
+ alloc_bootmem_cpumask_var(&of_spin_mask);
+
+ /*
+ * Mark threads which are still spinning in hold loops
+ *
+ * We know prom_init will not have started them if RTAS supports
+ * query-cpu-stopped-state.
+ */
+ if (rtas_token("query-cpu-stopped-state") == RTAS_UNKNOWN_SERVICE) {
+ if (cpu_has_feature(CPU_FTR_SMT)) {
+ for_each_present_cpu(i) {
+ if (cpu_thread_in_core(i) == 0)
+ cpumask_set_cpu(i, of_spin_mask);
+ }
+ } else
+ cpumask_copy(of_spin_mask, cpu_present_mask);
+
+ cpumask_clear_cpu(boot_cpuid, of_spin_mask);
+ }
+
+ /* Non-lpar has additional take/give timebase */
+ if (rtas_token("freeze-time-base") != RTAS_UNKNOWN_SERVICE) {
+ smp_ops->give_timebase = rtas_give_timebase;
+ smp_ops->take_timebase = rtas_take_timebase;
+ }
+
+ pr_debug(" <- smp_init_pSeries()\n");
+}
+
+void __init smp_init_pseries_mpic(void)
+{
+ smp_ops = &pSeries_mpic_smp_ops;
+
+ smp_init_pseries();
+}
+
+void __init smp_init_pseries_xics(void)
+{
+ smp_ops = &pSeries_xics_smp_ops;
+
+ smp_init_pseries();
+}