diff options
author | Jeremy Fitzhardinge <jeremy@goop.org> | 2006-12-07 02:14:02 +0100 |
---|---|---|
committer | Andi Kleen <andi@basil.nowhere.org> | 2006-12-07 02:14:02 +0100 |
commit | 62111195800d80c66cdc69063ea3145878c99fbf (patch) | |
tree | 35bc9792b3ac232e70e106ff2f4c0193c3bb72ff /arch/i386/kernel/cpu | |
parent | 9ca36101a8d74704d78f10910f89d62de96f9dc8 (diff) |
[PATCH] i386: Initialize the per-CPU data area
When a CPU is brought up, a PDA and GDT are allocated for it. The GDT's
__KERNEL_PDA entry is pointed to the allocated PDA memory, so that all
references using this segment descriptor will refer to the PDA.
This patch rearranges CPU initialization a bit, so that the GDT/PDA are set up
as early as possible in cpu_init(). Also for secondary CPUs, GDT+PDA are
preallocated and initialized so all the secondary CPU needs to do is set up
the ldt and load %gs. This will be important once smp_processor_id() and
current use the PDA.
In all cases, the PDA is set up in head.S, before a CPU starts running C code,
so the PDA is always available.
Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Cc: Chuck Ebbert <76306.1226@compuserve.com>
Cc: Zachary Amsden <zach@vmware.com>
Cc: Jan Beulich <jbeulich@novell.com>
Cc: Andi Kleen <ak@suse.de>
Cc: James Bottomley <James.Bottomley@SteelEye.com>
Cc: Matt Tolentino <matthew.e.tolentino@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Diffstat (limited to 'arch/i386/kernel/cpu')
-rw-r--r-- | arch/i386/kernel/cpu/common.c | 177 |
1 files changed, 134 insertions, 43 deletions
diff --git a/arch/i386/kernel/cpu/common.c b/arch/i386/kernel/cpu/common.c index 5532fc4e1bf..2534e25ed74 100644 --- a/arch/i386/kernel/cpu/common.c +++ b/arch/i386/kernel/cpu/common.c @@ -18,12 +18,16 @@ #include <asm/apic.h> #include <mach_apic.h> #endif +#include <asm/pda.h> #include "cpu.h" DEFINE_PER_CPU(struct Xgt_desc_struct, cpu_gdt_descr); EXPORT_PER_CPU_SYMBOL(cpu_gdt_descr); +struct i386_pda *_cpu_pda[NR_CPUS] __read_mostly; +EXPORT_SYMBOL(_cpu_pda); + static int cachesize_override __cpuinitdata = -1; static int disable_x86_fxsr __cpuinitdata; static int disable_x86_serial_nr __cpuinitdata = 1; @@ -588,41 +592,16 @@ void __init early_cpu_init(void) disable_pse = 1; #endif } -/* - * cpu_init() initializes state that is per-CPU. Some data is already - * initialized (naturally) in the bootstrap process, such as the GDT - * and IDT. We reload them nevertheless, this function acts as a - * 'CPU state barrier', nothing should get across. - */ -void __cpuinit cpu_init(void) + +__cpuinit int alloc_gdt(int cpu) { - int cpu = smp_processor_id(); - struct tss_struct * t = &per_cpu(init_tss, cpu); - struct thread_struct *thread = ¤t->thread; - struct desc_struct *gdt; struct Xgt_desc_struct *cpu_gdt_descr = &per_cpu(cpu_gdt_descr, cpu); + struct desc_struct *gdt; + struct i386_pda *pda; - if (cpu_test_and_set(cpu, cpu_initialized)) { - printk(KERN_WARNING "CPU#%d already initialized!\n", cpu); - for (;;) local_irq_enable(); - } - printk(KERN_INFO "Initializing CPU#%d\n", cpu); + gdt = (struct desc_struct *)cpu_gdt_descr->address; + pda = cpu_pda(cpu); - if (cpu_has_vme || cpu_has_tsc || cpu_has_de) - clear_in_cr4(X86_CR4_VME|X86_CR4_PVI|X86_CR4_TSD|X86_CR4_DE); - if (tsc_disable && cpu_has_tsc) { - printk(KERN_NOTICE "Disabling TSC...\n"); - /**** FIX-HPA: DOES THIS REALLY BELONG HERE? ****/ - clear_bit(X86_FEATURE_TSC, boot_cpu_data.x86_capability); - set_in_cr4(X86_CR4_TSD); - } - - /* The CPU hotplug case */ - if (cpu_gdt_descr->address) { - gdt = (struct desc_struct *)cpu_gdt_descr->address; - memset(gdt, 0, PAGE_SIZE); - goto old_gdt; - } /* * This is a horrible hack to allocate the GDT. The problem * is that cpu_init() is called really early for the boot CPU @@ -630,36 +609,117 @@ void __cpuinit cpu_init(void) * CPUs, when bootmem will have gone away */ if (NODE_DATA(0)->bdata->node_bootmem_map) { - gdt = (struct desc_struct *)alloc_bootmem_pages(PAGE_SIZE); - /* alloc_bootmem_pages panics on failure, so no check */ + BUG_ON(gdt != NULL || pda != NULL); + + gdt = alloc_bootmem_pages(PAGE_SIZE); + pda = alloc_bootmem(sizeof(*pda)); + /* alloc_bootmem(_pages) panics on failure, so no check */ + memset(gdt, 0, PAGE_SIZE); + memset(pda, 0, sizeof(*pda)); } else { - gdt = (struct desc_struct *)get_zeroed_page(GFP_KERNEL); - if (unlikely(!gdt)) { - printk(KERN_CRIT "CPU%d failed to allocate GDT\n", cpu); - for (;;) - local_irq_enable(); + /* GDT and PDA might already have been allocated if + this is a CPU hotplug re-insertion. */ + if (gdt == NULL) + gdt = (struct desc_struct *)get_zeroed_page(GFP_KERNEL); + + if (pda == NULL) + pda = kmalloc_node(sizeof(*pda), GFP_KERNEL, cpu_to_node(cpu)); + + if (unlikely(!gdt || !pda)) { + free_pages((unsigned long)gdt, 0); + kfree(pda); + return 0; } } -old_gdt: + + cpu_gdt_descr->address = (unsigned long)gdt; + cpu_pda(cpu) = pda; + + return 1; +} + +/* Initial PDA used by boot CPU */ +struct i386_pda boot_pda = { + ._pda = &boot_pda, +}; + +/* Initialize the CPU's GDT and PDA. The boot CPU does this for + itself, but secondaries find this done for them. */ +__cpuinit int init_gdt(int cpu, struct task_struct *idle) +{ + struct Xgt_desc_struct *cpu_gdt_descr = &per_cpu(cpu_gdt_descr, cpu); + struct desc_struct *gdt; + struct i386_pda *pda; + + /* For non-boot CPUs, the GDT and PDA should already have been + allocated. */ + if (!alloc_gdt(cpu)) { + printk(KERN_CRIT "CPU%d failed to allocate GDT or PDA\n", cpu); + return 0; + } + + gdt = (struct desc_struct *)cpu_gdt_descr->address; + pda = cpu_pda(cpu); + + BUG_ON(gdt == NULL || pda == NULL); + /* * Initialize the per-CPU GDT with the boot GDT, * and set up the GDT descriptor: */ memcpy(gdt, cpu_gdt_table, GDT_SIZE); cpu_gdt_descr->size = GDT_SIZE - 1; - cpu_gdt_descr->address = (unsigned long)gdt; + pack_descriptor((u32 *)&gdt[GDT_ENTRY_PDA].a, + (u32 *)&gdt[GDT_ENTRY_PDA].b, + (unsigned long)pda, sizeof(*pda) - 1, + 0x80 | DESCTYPE_S | 0x2, 0); /* present read-write data segment */ + + memset(pda, 0, sizeof(*pda)); + pda->_pda = pda; + + return 1; +} + +/* Common CPU init for both boot and secondary CPUs */ +static void __cpuinit _cpu_init(int cpu, struct task_struct *curr) +{ + struct tss_struct * t = &per_cpu(init_tss, cpu); + struct thread_struct *thread = &curr->thread; + struct Xgt_desc_struct *cpu_gdt_descr = &per_cpu(cpu_gdt_descr, cpu); + + /* Reinit these anyway, even if they've already been done (on + the boot CPU, this will transition from the boot gdt+pda to + the real ones). */ load_gdt(cpu_gdt_descr); + + if (cpu_test_and_set(cpu, cpu_initialized)) { + printk(KERN_WARNING "CPU#%d already initialized!\n", cpu); + for (;;) local_irq_enable(); + } + + printk(KERN_INFO "Initializing CPU#%d\n", cpu); + + if (cpu_has_vme || cpu_has_tsc || cpu_has_de) + clear_in_cr4(X86_CR4_VME|X86_CR4_PVI|X86_CR4_TSD|X86_CR4_DE); + if (tsc_disable && cpu_has_tsc) { + printk(KERN_NOTICE "Disabling TSC...\n"); + /**** FIX-HPA: DOES THIS REALLY BELONG HERE? ****/ + clear_bit(X86_FEATURE_TSC, boot_cpu_data.x86_capability); + set_in_cr4(X86_CR4_TSD); + } + load_idt(&idt_descr); /* * Set up and load the per-CPU TSS and LDT */ atomic_inc(&init_mm.mm_count); - current->active_mm = &init_mm; - BUG_ON(current->mm); - enter_lazy_tlb(&init_mm, current); + curr->active_mm = &init_mm; + if (curr->mm) + BUG(); + enter_lazy_tlb(&init_mm, curr); load_esp0(t, thread); set_tss_desc(cpu,t); @@ -690,6 +750,37 @@ old_gdt: mxcsr_feature_mask_init(); } +/* Entrypoint to initialize secondary CPU */ +void __cpuinit secondary_cpu_init(void) +{ + int cpu = smp_processor_id(); + struct task_struct *curr = current; + + _cpu_init(cpu, curr); +} + +/* + * cpu_init() initializes state that is per-CPU. Some data is already + * initialized (naturally) in the bootstrap process, such as the GDT + * and IDT. We reload them nevertheless, this function acts as a + * 'CPU state barrier', nothing should get across. + */ +void __cpuinit cpu_init(void) +{ + int cpu = smp_processor_id(); + struct task_struct *curr = current; + + /* Set up the real GDT and PDA, so we can transition from the + boot versions. */ + if (!init_gdt(cpu, curr)) { + /* failed to allocate something; not much we can do... */ + for (;;) + local_irq_enable(); + } + + _cpu_init(cpu, curr); +} + #ifdef CONFIG_HOTPLUG_CPU void __cpuinit cpu_uninit(void) { |