From 31139971b3dc9fbb2e8a8572fb81e6e8470f363a Mon Sep 17 00:00:00 2001 From: Paul Mackerras Date: Sat, 10 Sep 2005 21:13:13 +1000 Subject: [PATCH] [PATCH] ppc32: support hotplug cpu on powermacs This allows cpus to be off-lined on 32-bit SMP powermacs. When a cpu is off-lined, it is put into sleep mode with interrupts disabled. It can be on-lined again by asserting its soft-reset pin, which is connected to a GPIO pin. With this I can off-line the second cpu in my dual G4 powermac, which means that I can then suspend the machine (the suspend/resume code refuses to suspend if more than one cpu is online, and making it cope with multiple cpus is surprisingly messy). Signed-off-by: Paul Mackerras Signed-off-by: Linus Torvalds --- arch/ppc/Kconfig | 9 ++++ arch/ppc/kernel/head.S | 28 +++++------ arch/ppc/kernel/idle.c | 6 ++- arch/ppc/kernel/smp.c | 44 +++++++++++------ arch/ppc/platforms/pmac_sleep.S | 2 + arch/ppc/platforms/pmac_smp.c | 85 +++++++++++++++++++++------------ include/asm-ppc/smp.h | 6 +++ 7 files changed, 119 insertions(+), 61 deletions(-) diff --git a/arch/ppc/Kconfig b/arch/ppc/Kconfig index e3f1ce33e64..347ea284140 100644 --- a/arch/ppc/Kconfig +++ b/arch/ppc/Kconfig @@ -265,6 +265,15 @@ config PPC601_SYNC_FIX If in doubt, say Y here. +config HOTPLUG_CPU + bool "Support for enabling/disabling CPUs" + depends on SMP && HOTPLUG && EXPERIMENTAL && PPC_PMAC + ---help--- + Say Y here to be able to disable and re-enable individual + CPUs at runtime on SMP machines. + + Say N if you are unsure. + source arch/ppc/platforms/4xx/Kconfig source arch/ppc/platforms/85xx/Kconfig diff --git a/arch/ppc/kernel/head.S b/arch/ppc/kernel/head.S index 55daf1210f3..1960fb8c259 100644 --- a/arch/ppc/kernel/head.S +++ b/arch/ppc/kernel/head.S @@ -1023,23 +1023,21 @@ __secondary_start_gemini: andc r4,r4,r3 mtspr SPRN_HID0,r4 sync - bl gemini_prom_init b __secondary_start #endif /* CONFIG_GEMINI */ - .globl __secondary_start_psurge -__secondary_start_psurge: - li r24,1 /* cpu # */ - b __secondary_start_psurge99 - .globl __secondary_start_psurge2 -__secondary_start_psurge2: - li r24,2 /* cpu # */ - b __secondary_start_psurge99 - .globl __secondary_start_psurge3 -__secondary_start_psurge3: - li r24,3 /* cpu # */ - b __secondary_start_psurge99 -__secondary_start_psurge99: - /* we come in here with IR=0 and DR=1, and DBAT 0 + + .globl __secondary_start_pmac_0 +__secondary_start_pmac_0: + /* NB the entries for cpus 0, 1, 2 must each occupy 8 bytes. */ + li r24,0 + b 1f + li r24,1 + b 1f + li r24,2 + b 1f + li r24,3 +1: + /* on powersurge, we come in here with IR=0 and DR=1, and DBAT 0 set to map the 0xf0000000 - 0xffffffff region */ mfmsr r0 rlwinm r0,r0,0,28,26 /* clear DR (0x10) */ diff --git a/arch/ppc/kernel/idle.c b/arch/ppc/kernel/idle.c index 53547b6de45..fba29c876b6 100644 --- a/arch/ppc/kernel/idle.c +++ b/arch/ppc/kernel/idle.c @@ -22,6 +22,7 @@ #include #include #include +#include #include #include @@ -35,6 +36,7 @@ void default_idle(void) { void (*powersave)(void); + int cpu = smp_processor_id(); powersave = ppc_md.power_save; @@ -44,7 +46,7 @@ void default_idle(void) #ifdef CONFIG_SMP else { set_thread_flag(TIF_POLLING_NRFLAG); - while (!need_resched()) + while (!need_resched() && !cpu_is_offline(cpu)) barrier(); clear_thread_flag(TIF_POLLING_NRFLAG); } @@ -52,6 +54,8 @@ void default_idle(void) } if (need_resched()) schedule(); + if (cpu_is_offline(cpu) && system_state == SYSTEM_RUNNING) + cpu_die(); } /* diff --git a/arch/ppc/kernel/smp.c b/arch/ppc/kernel/smp.c index e70b587b9e5..726fe7ce174 100644 --- a/arch/ppc/kernel/smp.c +++ b/arch/ppc/kernel/smp.c @@ -45,6 +45,7 @@ cpumask_t cpu_online_map; cpumask_t cpu_possible_map; int smp_hw_index[NR_CPUS]; struct thread_info *secondary_ti; +static struct task_struct *idle_tasks[NR_CPUS]; EXPORT_SYMBOL(cpu_online_map); EXPORT_SYMBOL(cpu_possible_map); @@ -286,7 +287,8 @@ static void __devinit smp_store_cpu_info(int id) void __init smp_prepare_cpus(unsigned int max_cpus) { - int num_cpus, i; + int num_cpus, i, cpu; + struct task_struct *p; /* Fixup boot cpu */ smp_store_cpu_info(smp_processor_id()); @@ -308,6 +310,17 @@ void __init smp_prepare_cpus(unsigned int max_cpus) if (smp_ops->space_timers) smp_ops->space_timers(num_cpus); + + for_each_cpu(cpu) { + if (cpu == smp_processor_id()) + continue; + /* create a process for the processor */ + p = fork_idle(cpu); + if (IS_ERR(p)) + panic("failed fork for CPU %u: %li", cpu, PTR_ERR(p)); + p->thread_info->cpu = cpu; + idle_tasks[cpu] = p; + } } void __devinit smp_prepare_boot_cpu(void) @@ -334,12 +347,17 @@ int __devinit start_secondary(void *unused) set_dec(tb_ticks_per_jiffy); cpu_callin_map[cpu] = 1; - printk("CPU %i done callin...\n", cpu); + printk("CPU %d done callin...\n", cpu); smp_ops->setup_cpu(cpu); - printk("CPU %i done setup...\n", cpu); - local_irq_enable(); + printk("CPU %d done setup...\n", cpu); smp_ops->take_timebase(); - printk("CPU %i done timebase take...\n", cpu); + printk("CPU %d done timebase take...\n", cpu); + + spin_lock(&call_lock); + cpu_set(cpu, cpu_online_map); + spin_unlock(&call_lock); + + local_irq_enable(); cpu_idle(); return 0; @@ -347,17 +365,11 @@ int __devinit start_secondary(void *unused) int __cpu_up(unsigned int cpu) { - struct task_struct *p; char buf[32]; int c; - /* create a process for the processor */ - /* only regs.msr is actually used, and 0 is OK for it */ - p = fork_idle(cpu); - if (IS_ERR(p)) - panic("failed fork for CPU %u: %li", cpu, PTR_ERR(p)); - secondary_ti = p->thread_info; - p->thread_info->cpu = cpu; + secondary_ti = idle_tasks[cpu]->thread_info; + mb(); /* * There was a cache flush loop here to flush the cache @@ -389,7 +401,11 @@ int __cpu_up(unsigned int cpu) printk("Processor %d found.\n", cpu); smp_ops->give_timebase(); - cpu_set(cpu, cpu_online_map); + + /* Wait until cpu puts itself in the online map */ + while (!cpu_online(cpu)) + cpu_relax(); + return 0; } diff --git a/arch/ppc/platforms/pmac_sleep.S b/arch/ppc/platforms/pmac_sleep.S index 8d67adc7692..88419c77ac4 100644 --- a/arch/ppc/platforms/pmac_sleep.S +++ b/arch/ppc/platforms/pmac_sleep.S @@ -161,6 +161,8 @@ _GLOBAL(low_sleep_handler) addi r3,r3,sleep_storage@l stw r5,0(r3) + .globl low_cpu_die +low_cpu_die: /* Flush & disable all caches */ bl flush_disable_caches diff --git a/arch/ppc/platforms/pmac_smp.c b/arch/ppc/platforms/pmac_smp.c index 8e049dab4e6..794a23994b8 100644 --- a/arch/ppc/platforms/pmac_smp.c +++ b/arch/ppc/platforms/pmac_smp.c @@ -33,6 +33,7 @@ #include #include #include +#include #include #include @@ -55,9 +56,7 @@ * Powersurge (old powermac SMP) support. */ -extern void __secondary_start_psurge(void); -extern void __secondary_start_psurge2(void); /* Temporary horrible hack */ -extern void __secondary_start_psurge3(void); /* Temporary horrible hack */ +extern void __secondary_start_pmac_0(void); /* Addresses for powersurge registers */ #define HAMMERHEAD_BASE 0xf8000000 @@ -119,7 +118,7 @@ static volatile int sec_tb_reset = 0; static unsigned int pri_tb_hi, pri_tb_lo; static unsigned int pri_tb_stamp; -static void __init core99_init_caches(int cpu) +static void __devinit core99_init_caches(int cpu) { if (!cpu_has_feature(CPU_FTR_L2CR)) return; @@ -346,7 +345,7 @@ static int __init smp_psurge_probe(void) static void __init smp_psurge_kick_cpu(int nr) { - void (*start)(void) = __secondary_start_psurge; + unsigned long start = __pa(__secondary_start_pmac_0) + nr * 8; unsigned long a; /* may need to flush here if secondary bats aren't setup */ @@ -356,17 +355,7 @@ static void __init smp_psurge_kick_cpu(int nr) if (ppc_md.progress) ppc_md.progress("smp_psurge_kick_cpu", 0x353); - /* setup entry point of secondary processor */ - switch (nr) { - case 2: - start = __secondary_start_psurge2; - break; - case 3: - start = __secondary_start_psurge3; - break; - } - - out_be32(psurge_start, __pa(start)); + out_be32(psurge_start, start); mb(); psurge_set_ipi(nr); @@ -500,14 +489,14 @@ static int __init smp_core99_probe(void) return ncpus; } -static void __init smp_core99_kick_cpu(int nr) +static void __devinit smp_core99_kick_cpu(int nr) { unsigned long save_vector, new_vector; unsigned long flags; volatile unsigned long *vector = ((volatile unsigned long *)(KERNELBASE+0x100)); - if (nr < 1 || nr > 3) + if (nr < 0 || nr > 3) return; if (ppc_md.progress) ppc_md.progress("smp_core99_kick_cpu", 0x346); @@ -518,19 +507,9 @@ static void __init smp_core99_kick_cpu(int nr) save_vector = *vector; /* Setup fake reset vector that does - * b __secondary_start_psurge - KERNELBASE + * b __secondary_start_pmac_0 + nr*8 - KERNELBASE */ - switch(nr) { - case 1: - new_vector = (unsigned long)__secondary_start_psurge; - break; - case 2: - new_vector = (unsigned long)__secondary_start_psurge2; - break; - case 3: - new_vector = (unsigned long)__secondary_start_psurge3; - break; - } + new_vector = (unsigned long) __secondary_start_pmac_0 + nr * 8; *vector = 0x48000002 + new_vector - KERNELBASE; /* flush data cache and inval instruction cache */ @@ -554,7 +533,7 @@ static void __init smp_core99_kick_cpu(int nr) if (ppc_md.progress) ppc_md.progress("smp_core99_kick_cpu done", 0x347); } -static void __init smp_core99_setup_cpu(int cpu_nr) +static void __devinit smp_core99_setup_cpu(int cpu_nr) { /* Setup L2/L3 */ if (cpu_nr != 0) @@ -668,3 +647,47 @@ struct smp_ops_t core99_smp_ops __pmacdata = { .give_timebase = smp_core99_give_timebase, .take_timebase = smp_core99_take_timebase, }; + +#ifdef CONFIG_HOTPLUG_CPU + +int __cpu_disable(void) +{ + cpu_clear(smp_processor_id(), cpu_online_map); + + /* XXX reset cpu affinity here */ + openpic_set_priority(0xf); + asm volatile("mtdec %0" : : "r" (0x7fffffff)); + mb(); + udelay(20); + asm volatile("mtdec %0" : : "r" (0x7fffffff)); + return 0; +} + +extern void low_cpu_die(void) __attribute__((noreturn)); /* in pmac_sleep.S */ +static int cpu_dead[NR_CPUS]; + +void cpu_die(void) +{ + local_irq_disable(); + cpu_dead[smp_processor_id()] = 1; + mb(); + low_cpu_die(); +} + +void __cpu_die(unsigned int cpu) +{ + int timeout; + + timeout = 1000; + while (!cpu_dead[cpu]) { + if (--timeout == 0) { + printk("CPU %u refused to die!\n", cpu); + break; + } + msleep(1); + } + cpu_callin_map[cpu] = 0; + cpu_dead[cpu] = 0; +} + +#endif diff --git a/include/asm-ppc/smp.h b/include/asm-ppc/smp.h index 17530c232c7..829481c0a9d 100644 --- a/include/asm-ppc/smp.h +++ b/include/asm-ppc/smp.h @@ -41,6 +41,10 @@ extern void smp_send_xmon_break(int cpu); struct pt_regs; extern void smp_message_recv(int, struct pt_regs *); +extern int __cpu_disable(void); +extern void __cpu_die(unsigned int cpu); +extern void cpu_die(void) __attribute__((noreturn)); + #define NO_PROC_ID 0xFF /* No processor magic marker */ #define PROC_CHANGE_PENALTY 20 @@ -64,6 +68,8 @@ extern struct klock_info_struct klock_info; #else /* !(CONFIG_SMP) */ +static inline void cpu_die(void) { } + #endif /* !(CONFIG_SMP) */ #endif /* !(_PPC_SMP_H) */ -- 2.41.1