[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>
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committed by
Linus Torvalds
parent
1e275d406b
commit
2b932f6cf0
@@ -4,6 +4,7 @@
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#include <linux/smp.h>
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#include <linux/module.h>
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#include <linux/percpu.h>
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#include <linux/bootmem.h>
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#include <asm/semaphore.h>
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#include <asm/processor.h>
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#include <asm/i387.h>
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@@ -18,6 +19,9 @@
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#include "cpu.h"
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DEFINE_PER_CPU(struct Xgt_desc_struct, cpu_gdt_descr);
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EXPORT_PER_CPU_SYMBOL(cpu_gdt_descr);
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DEFINE_PER_CPU(unsigned char, cpu_16bit_stack[CPU_16BIT_STACK_SIZE]);
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EXPORT_PER_CPU_SYMBOL(cpu_16bit_stack);
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@@ -571,8 +575,9 @@ void __devinit cpu_init(void)
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int cpu = smp_processor_id();
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struct tss_struct * t = &per_cpu(init_tss, cpu);
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struct thread_struct *thread = ¤t->thread;
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struct desc_struct *gdt = get_cpu_gdt_table(cpu);
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struct desc_struct *gdt;
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__u32 stk16_off = (__u32)&per_cpu(cpu_16bit_stack, cpu);
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struct Xgt_desc_struct *cpu_gdt_descr = &per_cpu(cpu_gdt_descr, cpu);
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if (cpu_test_and_set(cpu, cpu_initialized)) {
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printk(KERN_WARNING "CPU#%d already initialized!\n", cpu);
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@@ -589,6 +594,25 @@ void __devinit cpu_init(void)
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set_in_cr4(X86_CR4_TSD);
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}
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/*
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* This is a horrible hack to allocate the GDT. The problem
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* is that cpu_init() is called really early for the boot CPU
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* (and hence needs bootmem) but much later for the secondary
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* CPUs, when bootmem will have gone away
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*/
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if (NODE_DATA(0)->bdata->node_bootmem_map) {
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gdt = (struct desc_struct *)alloc_bootmem_pages(PAGE_SIZE);
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/* alloc_bootmem_pages panics on failure, so no check */
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memset(gdt, 0, PAGE_SIZE);
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} else {
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gdt = (struct desc_struct *)get_zeroed_page(GFP_KERNEL);
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if (unlikely(!gdt)) {
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printk(KERN_CRIT "CPU%d failed to allocate GDT\n", cpu);
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for (;;)
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local_irq_enable();
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}
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}
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/*
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* Initialize the per-CPU GDT with the boot GDT,
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* and set up the GDT descriptor:
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@@ -601,10 +625,10 @@ void __devinit cpu_init(void)
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((((__u64)stk16_off) << 32) & 0xff00000000000000ULL) |
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(CPU_16BIT_STACK_SIZE - 1);
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cpu_gdt_descr[cpu].size = GDT_SIZE - 1;
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cpu_gdt_descr[cpu].address = (unsigned long)gdt;
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cpu_gdt_descr->size = GDT_SIZE - 1;
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cpu_gdt_descr->address = (unsigned long)gdt;
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load_gdt(&cpu_gdt_descr[cpu]);
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load_gdt(cpu_gdt_descr);
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load_idt(&idt_descr);
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/*
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