[IA64] support for cpu0 removal

here is the BSP removal support for IA64. Its pretty much the same thing that
was released a while back, but has your feedback incorporated.

- Removed CONFIG_BSP_REMOVE_WORKAROUND and associated cmdline param
- Fixed compile issue with sn2/zx1 due to a undefined fix_b0_for_bsp
- some formatting nits (whitespace etc)

This has been tested on tiger and long back by alex on hp systems as well.

Signed-off-by: Ashok Raj <ashok.raj@intel.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>

diff --git a/arch/ia64/Kconfig b/arch/ia64/Kconfig
index 199eeaf..5e0f58e 100644 (file)
--- a/arch/ia64/Kconfig
+++ b/arch/ia64/Kconfig
@@ -272,6 +272,25 @@ config SCHED_SMT
          Intel IA64 chips with MultiThreading at a cost of slightly increased
          overhead in some places. If unsure say N here.
 
+config PERMIT_BSP_REMOVE
+       bool "Support removal of Bootstrap Processor"
+       depends on HOTPLUG_CPU
+       default n
+       ---help---
+       Say Y here if your platform SAL will support removal of BSP with HOTPLUG_CPU
+       support. 
+
+config FORCE_CPEI_RETARGET
+       bool "Force assumption that CPEI can be re-targetted"
+       depends on PERMIT_BSP_REMOVE
+       default n
+       ---help---
+       Say Y if you need to force the assumption that CPEI can be re-targetted to
+       any cpu in the system. This hint is available via ACPI 3.0 specifications.
+       Tiger4 systems are capable of re-directing CPEI to any CPU other than BSP.
+       This option it useful to enable this feature on older BIOS's as well.
+       You can also enable this by using boot command line option force_cpei=1.
+
 config PREEMPT
        bool "Preemptible Kernel"
         help

diff --git a/arch/ia64/configs/tiger_defconfig b/arch/ia64/configs/tiger_defconfig
index b1e8f09..aed034d 100644 (file)
--- a/arch/ia64/configs/tiger_defconfig
+++ b/arch/ia64/configs/tiger_defconfig
@@ -114,6 +114,8 @@ CONFIG_FORCE_MAX_ZONEORDER=17
 CONFIG_SMP=y
 CONFIG_NR_CPUS=4
 CONFIG_HOTPLUG_CPU=y
+CONFIG_PERMIT_BSP_REMOVE=y
+CONFIG_FORCE_CPEI_RETARGET=y
 # CONFIG_SCHED_SMT is not set
 # CONFIG_PREEMPT is not set
 CONFIG_SELECT_MEMORY_MODEL=y

diff --git a/arch/ia64/kernel/acpi.c b/arch/ia64/kernel/acpi.c
index 9ad94dd..fe1d90b 100644 (file)
--- a/arch/ia64/kernel/acpi.c
+++ b/arch/ia64/kernel/acpi.c
@@ -287,16 +287,20 @@ acpi_parse_plat_int_src(acpi_table_entry_header * header,
 unsigned int can_cpei_retarget(void)
 {
        extern int cpe_vector;
+       extern unsigned int force_cpei_retarget;
 
        /*
         * Only if CPEI is supported and the override flag
         * is present, otherwise return that its re-targettable
         * if we are in polling mode.
         */
-       if (cpe_vector > 0 && !acpi_cpei_override)
-               return 0;
-       else
-               return 1;
+       if (cpe_vector > 0) {
+               if (acpi_cpei_override || force_cpei_retarget)
+                       return 1;
+               else
+                       return 0;
+       }
+       return 1;
 }
 
 unsigned int is_cpu_cpei_target(unsigned int cpu)

diff --git a/arch/ia64/kernel/iosapic.c b/arch/ia64/kernel/iosapic.c
index 574084f..37ac742 100644 (file)
--- a/arch/ia64/kernel/iosapic.c
+++ b/arch/ia64/kernel/iosapic.c
@@ -631,6 +631,7 @@ get_target_cpu (unsigned int gsi, int vector)
 {
 #ifdef CONFIG_SMP
        static int cpu = -1;
+       extern int cpe_vector;
 
        /*
         * In case of vector shared by multiple RTEs, all RTEs that
@@ -653,6 +654,11 @@ get_target_cpu (unsigned int gsi, int vector)
        if (!cpu_online(smp_processor_id()))
                return cpu_physical_id(smp_processor_id());
 
+#ifdef CONFIG_ACPI
+               if (cpe_vector > 0 && vector == IA64_CPEP_VECTOR)
+                       return get_cpei_target_cpu();
+#endif
+
 #ifdef CONFIG_NUMA
        {
                int num_cpus, cpu_index, iosapic_index, numa_cpu, i = 0;

diff --git a/arch/ia64/kernel/irq.c b/arch/ia64/kernel/irq.c
index d33244c..5ce908e 100644 (file)
--- a/arch/ia64/kernel/irq.c
+++ b/arch/ia64/kernel/irq.c
@@ -163,8 +163,19 @@ void fixup_irqs(void)
 {
        unsigned int irq;
        extern void ia64_process_pending_intr(void);
+       extern void ia64_disable_timer(void);
+       extern volatile int time_keeper_id;
+
+       ia64_disable_timer();
+
+       /*
+        * Find a new timesync master
+        */
+       if (smp_processor_id() == time_keeper_id) {
+               time_keeper_id = first_cpu(cpu_online_map);
+               printk ("CPU %d is now promoted to time-keeper master\n", time_keeper_id);
+       }
 
-       ia64_set_itv(1<<16);
        /*
         * Phase 1: Locate irq's bound to this cpu and
         * relocate them for cpu removal.

diff --git a/arch/ia64/kernel/mca.c b/arch/ia64/kernel/mca.c
index 355af15..967571b 100644 (file)
--- a/arch/ia64/kernel/mca.c
+++ b/arch/ia64/kernel/mca.c
@@ -289,6 +289,7 @@ ia64_mca_log_sal_error_record(int sal_info_type)
 #ifdef CONFIG_ACPI
 
 int cpe_vector = -1;
+int ia64_cpe_irq = -1;
 
 static irqreturn_t
 ia64_mca_cpe_int_handler (int cpe_irq, void *arg, struct pt_regs *ptregs)
@@ -1444,11 +1445,13 @@ void __devinit
 ia64_mca_cpu_init(void *cpu_data)
 {
        void *pal_vaddr;
+       static int first_time = 1;
 
-       if (smp_processor_id() == 0) {
+       if (first_time) {
                void *mca_data;
                int cpu;
 
+               first_time = 0;
                mca_data = alloc_bootmem(sizeof(struct ia64_mca_cpu)
                                         * NR_CPUS + KERNEL_STACK_SIZE);
                mca_data = (void *)(((unsigned long)mca_data +
@@ -1704,6 +1707,7 @@ ia64_mca_late_init(void)
                                        desc = irq_descp(irq);
                                        desc->status |= IRQ_PER_CPU;
                                        setup_irq(irq, &mca_cpe_irqaction);
+                                       ia64_cpe_irq = irq;
                                }
                        ia64_mca_register_cpev(cpe_vector);
                        IA64_MCA_DEBUG("%s: CPEI/P setup and enabled.\n", __FUNCTION__);

diff --git a/arch/ia64/kernel/perfmon.c b/arch/ia64/kernel/perfmon.c
index 410d480..18c51c3 100644 (file)
--- a/arch/ia64/kernel/perfmon.c
+++ b/arch/ia64/kernel/perfmon.c
@@ -6718,6 +6718,7 @@ __initcall(pfm_init);
 void
 pfm_init_percpu (void)
 {
+       static int first_time=1;
        /*
         * make sure no measurement is active
         * (may inherit programmed PMCs from EFI).
@@ -6730,8 +6731,10 @@ pfm_init_percpu (void)
         */
        pfm_unfreeze_pmu();
 
-       if (smp_processor_id() == 0)
+       if (first_time) {
                register_percpu_irq(IA64_PERFMON_VECTOR, &perfmon_irqaction);
+               first_time=0;
+       }
 
        ia64_setreg(_IA64_REG_CR_PMV, IA64_PERFMON_VECTOR);
        ia64_srlz_d();

diff --git a/arch/ia64/kernel/smpboot.c b/arch/ia64/kernel/smpboot.c
index 8f44e7d..e9d37bf 100644 (file)
--- a/arch/ia64/kernel/smpboot.c
+++ b/arch/ia64/kernel/smpboot.c
@@ -70,6 +70,12 @@
 #endif
 
 #ifdef CONFIG_HOTPLUG_CPU
+#ifdef CONFIG_PERMIT_BSP_REMOVE
+#define bsp_remove_ok  1
+#else
+#define bsp_remove_ok  0
+#endif
+
 /*
  * Store all idle threads, this can be reused instead of creating
  * a new thread. Also avoids complicated thread destroy functionality
@@ -104,7 +110,7 @@ struct sal_to_os_boot *sal_state_for_booting_cpu = &sal_boot_rendez_state[0];
 /*
  * ITC synchronization related stuff:
  */
-#define MASTER 0
+#define MASTER (0)
 #define SLAVE  (SMP_CACHE_BYTES/8)
 
 #define NUM_ROUNDS     64      /* magic value */
@@ -151,6 +157,27 @@ char __initdata no_int_routing;
 
 unsigned char smp_int_redirect; /* are INT and IPI redirectable by the chipset? */
 
+#ifdef CONFIG_FORCE_CPEI_RETARGET
+#define CPEI_OVERRIDE_DEFAULT  (1)
+#else
+#define CPEI_OVERRIDE_DEFAULT  (0)
+#endif
+
+unsigned int force_cpei_retarget = CPEI_OVERRIDE_DEFAULT;
+
+static int __init
+cmdl_force_cpei(char *str)
+{
+       int value=0;
+
+       get_option (&str, &value);
+       force_cpei_retarget = value;
+
+       return 1;
+}
+
+__setup("force_cpei=", cmdl_force_cpei);
+
 static int __init
 nointroute (char *str)
 {
@@ -161,6 +188,27 @@ nointroute (char *str)
 
 __setup("nointroute", nointroute);
 
+static void fix_b0_for_bsp(void)
+{
+#ifdef CONFIG_HOTPLUG_CPU
+       int cpuid;
+       static int fix_bsp_b0 = 1;
+
+       cpuid = smp_processor_id();
+
+       /*
+        * Cache the b0 value on the first AP that comes up
+        */
+       if (!(fix_bsp_b0 && cpuid))
+               return;
+
+       sal_boot_rendez_state[0].br[0] = sal_boot_rendez_state[cpuid].br[0];
+       printk ("Fixed BSP b0 value from CPU %d\n", cpuid);
+
+       fix_bsp_b0 = 0;
+#endif
+}
+
 void
 sync_master (void *arg)
 {
@@ -327,8 +375,9 @@ smp_setup_percpu_timer (void)
 static void __devinit
 smp_callin (void)
 {
-       int cpuid, phys_id;
+       int cpuid, phys_id, itc_master;
        extern void ia64_init_itm(void);
+       extern volatile int time_keeper_id;
 
 #ifdef CONFIG_PERFMON
        extern void pfm_init_percpu(void);
@@ -336,6 +385,7 @@ smp_callin (void)
 
        cpuid = smp_processor_id();
        phys_id = hard_smp_processor_id();
+       itc_master = time_keeper_id;
 
        if (cpu_online(cpuid)) {
                printk(KERN_ERR "huh, phys CPU#0x%x, CPU#0x%x already present??\n",
@@ -343,6 +393,8 @@ smp_callin (void)
                BUG();
        }
 
+       fix_b0_for_bsp();
+
        lock_ipi_calllock();
        cpu_set(cpuid, cpu_online_map);
        unlock_ipi_calllock();
@@ -365,8 +417,8 @@ smp_callin (void)
                 * calls spin_unlock_bh(), which calls spin_unlock_bh(), which calls
                 * local_bh_enable(), which bugs out if irqs are not enabled...
                 */
-               Dprintk("Going to syncup ITC with BP.\n");
-               ia64_sync_itc(0);
+               Dprintk("Going to syncup ITC with ITC Master.\n");
+               ia64_sync_itc(itc_master);
        }
 
        /*
@@ -638,6 +690,47 @@ remove_siblinginfo(int cpu)
 }
 
 extern void fixup_irqs(void);
+
+int migrate_platform_irqs(unsigned int cpu)
+{
+       int new_cpei_cpu;
+       irq_desc_t *desc = NULL;
+       cpumask_t       mask;
+       int             retval = 0;
+
+       /*
+        * dont permit CPEI target to removed.
+        */
+       if (cpe_vector > 0 && is_cpu_cpei_target(cpu)) {
+               printk ("CPU (%d) is CPEI Target\n", cpu);
+               if (can_cpei_retarget()) {
+                       /*
+                        * Now re-target the CPEI to a different processor
+                        */
+                       new_cpei_cpu = any_online_cpu(cpu_online_map);
+                       mask = cpumask_of_cpu(new_cpei_cpu);
+                       set_cpei_target_cpu(new_cpei_cpu);
+                       desc = irq_descp(ia64_cpe_irq);
+                       /*
+                        * Switch for now, immediatly, we need to do fake intr
+                        * as other interrupts, but need to study CPEI behaviour with
+                        * polling before making changes.
+                        */
+                       if (desc) {
+                               desc->handler->disable(ia64_cpe_irq);
+                               desc->handler->set_affinity(ia64_cpe_irq, mask);
+                               desc->handler->enable(ia64_cpe_irq);
+                               printk ("Re-targetting CPEI to cpu %d\n", new_cpei_cpu);
+                       }
+               }
+               if (!desc) {
+                       printk ("Unable to retarget CPEI, offline cpu [%d] failed\n", cpu);
+                       retval = -EBUSY;
+               }
+       }
+       return retval;
+}
+
 /* must be called with cpucontrol mutex held */
 int __cpu_disable(void)
 {
@@ -646,8 +739,17 @@ int __cpu_disable(void)
        /*
         * dont permit boot processor for now
         */
-       if (cpu == 0)
-               return -EBUSY;
+       if (cpu == 0 && !bsp_remove_ok) {
+               printk ("Your platform does not support removal of BSP\n");
+               return (-EBUSY);
+       }
+
+       cpu_clear(cpu, cpu_online_map);
+
+       if (migrate_platform_irqs(cpu)) {
+               cpu_set(cpu, cpu_online_map);
+               return (-EBUSY);
+       }
 
        remove_siblinginfo(cpu);
        cpu_clear(cpu, cpu_online_map);

diff --git a/arch/ia64/kernel/time.c b/arch/ia64/kernel/time.c
index 028a2b9..1ca130a 100644 (file)
--- a/arch/ia64/kernel/time.c
+++ b/arch/ia64/kernel/time.c
@@ -32,7 +32,7 @@
 
 extern unsigned long wall_jiffies;
 
-#define TIME_KEEPER_ID 0       /* smp_processor_id() of time-keeper */
+volatile int time_keeper_id = 0; /* smp_processor_id() of time-keeper */
 
 #ifdef CONFIG_IA64_DEBUG_IRQ
 
@@ -71,7 +71,7 @@ timer_interrupt (int irq, void *dev_id, struct pt_regs *regs)
 
                new_itm += local_cpu_data->itm_delta;
 
-               if (smp_processor_id() == TIME_KEEPER_ID) {
+               if (smp_processor_id() == time_keeper_id) {
                        /*
                         * Here we are in the timer irq handler. We have irqs locally
                         * disabled, but we don't know if the timer_bh is running on
@@ -236,6 +236,11 @@ static struct irqaction timer_irqaction = {
        .name =         "timer"
 };
 
+void __devinit ia64_disable_timer(void)
+{
+       ia64_set_itv(1 << 16);
+}
+
 void __init
 time_init (void)
 {

diff --git a/arch/ia64/mm/contig.c b/arch/ia64/mm/contig.c
index acaaec4..9855ba3 100644 (file)
--- a/arch/ia64/mm/contig.c
+++ b/arch/ia64/mm/contig.c
@@ -181,13 +181,15 @@ per_cpu_init (void)
 {
        void *cpu_data;
        int cpu;
+       static int first_time=1;
 
        /*
         * get_free_pages() cannot be used before cpu_init() done.  BSP
         * allocates "NR_CPUS" pages for all CPUs to avoid that AP calls
         * get_zeroed_page().
         */
-       if (smp_processor_id() == 0) {
+       if (first_time) {
+               first_time=0;
                cpu_data = __alloc_bootmem(PERCPU_PAGE_SIZE * NR_CPUS,
                                           PERCPU_PAGE_SIZE, __pa(MAX_DMA_ADDRESS));
                for (cpu = 0; cpu < NR_CPUS; cpu++) {

diff --git a/arch/ia64/mm/discontig.c b/arch/ia64/mm/discontig.c
index c87d6d1..573d5cc 100644 (file)
--- a/arch/ia64/mm/discontig.c
+++ b/arch/ia64/mm/discontig.c
@@ -528,12 +528,17 @@ void __init find_memory(void)
 void *per_cpu_init(void)
 {
        int cpu;
+       static int first_time = 1;
+
 
        if (smp_processor_id() != 0)
                return __per_cpu_start + __per_cpu_offset[smp_processor_id()];
 
-       for (cpu = 0; cpu < NR_CPUS; cpu++)
-               per_cpu(local_per_cpu_offset, cpu) = __per_cpu_offset[cpu];
+       if (first_time) {
+               first_time = 0;
+               for (cpu = 0; cpu < NR_CPUS; cpu++)
+                       per_cpu(local_per_cpu_offset, cpu) = __per_cpu_offset[cpu];
+       }
 
        return __per_cpu_start + __per_cpu_offset[smp_processor_id()];
 }

diff --git a/include/asm-ia64/mca.h b/include/asm-ia64/mca.h
index c7d9c9e..bfbbb8d 100644 (file)
--- a/include/asm-ia64/mca.h
+++ b/include/asm-ia64/mca.h
@@ -131,6 +131,8 @@ struct ia64_mca_cpu {
 /* Array of physical addresses of each CPU's MCA area.  */
 extern unsigned long __per_cpu_mca[NR_CPUS];
 
+extern int cpe_vector;
+extern int ia64_cpe_irq;
 extern void ia64_mca_init(void);
 extern void ia64_mca_cpu_init(void *);
 extern void ia64_os_mca_dispatch(void);