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[PATCH] i386: Page-align the GDT

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Xen wants a dedicated page for the GDT.  I believe VMI likes it too.
lguest, KVM and native don't care.

Simple transformation to page-aligned "struct gdt_page".

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andi Kleen <ak@suse.de>
Acked-by: Jeremy Fitzhardinge <jeremy@xensource.com>
This commit is contained in:
Jeremy Fitzhardinge 2007-05-02 19:27:15 +02:00 committed by Andi Kleen
parent 39b7ee0685
commit 7a61d35d4b
5 changed files with 13 additions and 8 deletions
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6
arch/i386/kernel/cpu/common.c
View file

@ -22,7 +22,7 @@
#include "cpu.h"
DEFINE_PER_CPU(struct desc_struct, cpu_gdt[GDT_ENTRIES]) = {
DEFINE_PER_CPU(struct gdt_page, gdt_page) = { .gdt = {
[GDT_ENTRY_KERNEL_CS] = { 0x0000ffff, 0x00cf9a00 },
[GDT_ENTRY_KERNEL_DS] = { 0x0000ffff, 0x00cf9200 },
[GDT_ENTRY_DEFAULT_USER_CS] = { 0x0000ffff, 0x00cffa00 },
@ -48,8 +48,8 @@ DEFINE_PER_CPU(struct desc_struct, cpu_gdt[GDT_ENTRIES]) = {
[GDT_ENTRY_ESPFIX_SS] = { 0x00000000, 0x00c09200 },
[GDT_ENTRY_PDA] = { 0x00000000, 0x00c09200 }, /* set in setup_pda */
};
EXPORT_PER_CPU_SYMBOL_GPL(cpu_gdt);
} };
EXPORT_PER_CPU_SYMBOL_GPL(gdt_page);
DEFINE_PER_CPU(struct i386_pda, _cpu_pda);
EXPORT_PER_CPU_SYMBOL(_cpu_pda);

2
arch/i386/kernel/entry.S
View file

@ -557,7 +557,7 @@ END(syscall_badsys)
#define FIXUP_ESPFIX_STACK \
/* since we are on a wrong stack, we cant make it a C code :( */ \
movl %fs:PDA_cpu, %ebx; \
PER_CPU(cpu_gdt, %ebx); \
PER_CPU(gdt_page, %ebx); \
GET_DESC_BASE(GDT_ENTRY_ESPFIX_SS, %ebx, %eax, %ax, %al, %ah); \
addl %esp, %eax; \
pushl $__KERNEL_DS; \

2
arch/i386/kernel/head.S
View file

@ -598,7 +598,7 @@ idt_descr:
.word 0 # 32 bit align gdt_desc.address
ENTRY(early_gdt_descr)
.word GDT_ENTRIES*8-1
.long per_cpu__cpu_gdt /* Overwritten for secondary CPUs */
.long per_cpu__gdt_page /* Overwritten for secondary CPUs */
/*
* The boot_gdt must mirror the equivalent in setup.S and is

2
arch/i386/kernel/traps.c
View file

@ -1030,7 +1030,7 @@ fastcall void do_spurious_interrupt_bug(struct pt_regs * regs,
fastcall unsigned long patch_espfix_desc(unsigned long uesp,
unsigned long kesp)
{
struct desc_struct *gdt = __get_cpu_var(cpu_gdt);
struct desc_struct *gdt = __get_cpu_var(gdt_page).gdt;
unsigned long base = (kesp - uesp) & -THREAD_SIZE;
unsigned long new_kesp = kesp - base;
unsigned long lim_pages = (new_kesp | (THREAD_SIZE - 1)) >> PAGE_SHIFT;

9
include/asm-i386/desc.h
View file

@ -18,10 +18,15 @@ struct Xgt_desc_struct {
unsigned short pad;
} __attribute__ ((packed));
DECLARE_PER_CPU(struct desc_struct, cpu_gdt[GDT_ENTRIES]);
struct gdt_page
{
struct desc_struct gdt[GDT_ENTRIES];
} __attribute__((aligned(PAGE_SIZE)));
DECLARE_PER_CPU(struct gdt_page, gdt_page);
static inline struct desc_struct *get_cpu_gdt_table(unsigned int cpu)
{
return per_cpu(cpu_gdt, cpu);
return per_cpu(gdt_page, cpu).gdt;
}
extern struct Xgt_desc_struct idt_descr;