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authorJames Bottomley <James.Bottomley@SteelEye.com>2006-02-24 13:04:14 -0800
committerLinus Torvalds <torvalds@g5.osdl.org>2006-02-24 14:31:38 -0800
commit2b932f6cf052920fb3a6281499e08209b08f5086 (patch)
treec2710e09dd40ee9733bcd77234d6373acec741d2 /arch/i386/kernel/cpu
parent1e275d406bf6b88e4de6925cf594b64bb2ec49bc (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.c32
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 = &current->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);
/*