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Commit 7a61d35d authored by Jeremy Fitzhardinge's avatar Jeremy Fitzhardinge Committed by Andi Kleen
Browse files

[PATCH] i386: Page-align the GDT 



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: default avatarRusty Russell <rusty@rustcorp.com.au>
Signed-off-by: default avatarAndi Kleen <ak@suse.de>
Acked-by: default avatarJeremy Fitzhardinge <jeremy@xensource.com>
parent 39b7ee06

arch/i386/kernel/cpu/common.c

+3 −3
Original line number Diff line number Diff line
@@ -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);

arch/i386/kernel/entry.S

+1 −1
Original line number Diff line number Diff line
@@ -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; \

arch/i386/kernel/head.S

+1 −1
Original line number Diff line number Diff line
@@ -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

arch/i386/kernel/traps.c

+1 −1
Original line number Diff line number Diff line
@@ -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;

include/asm-i386/desc.h

+7 −2
Original line number Diff line number Diff line
@@ -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;