diff options
author | James Bottomley <James.Bottomley@SteelEye.com> | 2006-02-24 13:04:14 -0800 |
---|---|---|
committer | Linus Torvalds <torvalds@g5.osdl.org> | 2006-02-24 14:31:38 -0800 |
commit | 2b932f6cf052920fb3a6281499e08209b08f5086 (patch) | |
tree | c2710e09dd40ee9733bcd77234d6373acec741d2 /arch/i386/kernel/cpu | |
parent | 1e275d406bf6b88e4de6925cf594b64bb2ec49bc (diff) |
[PATCH] x86: fix broken SMP boot sequence
Recent GDT changes broke the SMP boot sequence if the booting CPU is
numbered anything other than zero. There's also a subtle source of error
in that the boot time CPU now uses cpu_gdt_table (which is actually the GDT
for booting CPUs in head.S). This patch fixes both problems by making GDT
descriptors themselves allocated from a per_cpu area and switching to them
in cpu_init(), which now means that cpu_gdt_table is exclusively used for
booting CPUs again.
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
Cc: Zachary Amsden <zach@vmware.com>
Cc: Matt Tolentino <metolent@snoqualmie.dp.intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'arch/i386/kernel/cpu')
-rw-r--r-- | arch/i386/kernel/cpu/common.c | 32 |
1 files changed, 28 insertions, 4 deletions
diff --git a/arch/i386/kernel/cpu/common.c b/arch/i386/kernel/cpu/common.c index 7eb9213734a..4ecd4b326de 100644 --- a/arch/i386/kernel/cpu/common.c +++ b/arch/i386/kernel/cpu/common.c @@ -4,6 +4,7 @@ #include <linux/smp.h> #include <linux/module.h> #include <linux/percpu.h> +#include <linux/bootmem.h> #include <asm/semaphore.h> #include <asm/processor.h> #include <asm/i387.h> @@ -18,6 +19,9 @@ #include "cpu.h" +DEFINE_PER_CPU(struct Xgt_desc_struct, cpu_gdt_descr); +EXPORT_PER_CPU_SYMBOL(cpu_gdt_descr); + DEFINE_PER_CPU(unsigned char, cpu_16bit_stack[CPU_16BIT_STACK_SIZE]); EXPORT_PER_CPU_SYMBOL(cpu_16bit_stack); @@ -571,8 +575,9 @@ void __devinit cpu_init(void) int cpu = smp_processor_id(); struct tss_struct * t = &per_cpu(init_tss, cpu); struct thread_struct *thread = ¤t->thread; - struct desc_struct *gdt = get_cpu_gdt_table(cpu); + struct desc_struct *gdt; __u32 stk16_off = (__u32)&per_cpu(cpu_16bit_stack, cpu); + struct Xgt_desc_struct *cpu_gdt_descr = &per_cpu(cpu_gdt_descr, cpu); if (cpu_test_and_set(cpu, cpu_initialized)) { printk(KERN_WARNING "CPU#%d already initialized!\n", cpu); @@ -590,6 +595,25 @@ void __devinit cpu_init(void) } /* + * This is a horrible hack to allocate the GDT. The problem + * is that cpu_init() is called really early for the boot CPU + * (and hence needs bootmem) but much later for the secondary + * 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 */ + memset(gdt, 0, PAGE_SIZE); + } 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(); + } + } + + /* * Initialize the per-CPU GDT with the boot GDT, * and set up the GDT descriptor: */ @@ -601,10 +625,10 @@ void __devinit cpu_init(void) ((((__u64)stk16_off) << 32) & 0xff00000000000000ULL) | (CPU_16BIT_STACK_SIZE - 1); - cpu_gdt_descr[cpu].size = GDT_SIZE - 1; - cpu_gdt_descr[cpu].address = (unsigned long)gdt; + cpu_gdt_descr->size = GDT_SIZE - 1; + cpu_gdt_descr->address = (unsigned long)gdt; - load_gdt(&cpu_gdt_descr[cpu]); + load_gdt(cpu_gdt_descr); load_idt(&idt_descr); /* |