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Message-Id: <1173186107.4644.41.camel@localhost.localdomain>
Date: Wed, 07 Mar 2007 00:01:47 +1100
From: Rusty Russell <rusty@...tcorp.com.au>
To: lkml - Kernel Mailing List <linux-kernel@...r.kernel.org>
Cc: Zachary Amsden <zach@...are.com>,
Jeremy Fitzhardinge <jeremy@...source.com>,
Ingo Molnar <mingo@...e.hu>,
Andrew Morton <akpm@...ux-foundation.org>,
Andi Kleen <ak@...e.de>
Subject: [PATCH 7/8] 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: Rusty Russell <rusty@...tcorp.com.au>
diff -r 576929b5b43f arch/i386/kernel/cpu/common.c
--- a/arch/i386/kernel/cpu/common.c Tue Mar 06 16:28:38 2007 +1100
+++ b/arch/i386/kernel/cpu/common.c Tue Mar 06 16:47:11 2007 +1100
@@ -22,8 +22,8 @@
#include "cpu.h"
-DEFINE_PER_CPU(struct desc_struct, cpu_gdt[GDT_ENTRIES]);
-EXPORT_PER_CPU_SYMBOL_GPL(cpu_gdt);
+DEFINE_PER_CPU(struct gdt_page, gdt_page);
+EXPORT_PER_CPU_SYMBOL_GPL(gdt_page);
DEFINE_PER_CPU(struct i386_pda, _cpu_pda);
EXPORT_PER_CPU_SYMBOL(_cpu_pda);
@@ -628,7 +628,7 @@ static inline void set_kernel_fs(void)
will soon come up. */
__cpuinit void init_gdt(int cpu, struct task_struct *idle)
{
- struct desc_struct *gdt = per_cpu(cpu_gdt, cpu);
+ struct desc_struct *gdt = per_cpu(gdt_page, cpu).gdt;
struct i386_pda *pda = &per_cpu(_cpu_pda, cpu);
/* Based on boot_gdt_table: set PDA so it can be used immediately */
@@ -649,7 +649,7 @@ void __cpuinit cpu_set_gdt(int cpu)
{
struct Xgt_desc_struct gdt_descr;
- gdt_descr.address = (unsigned long)per_cpu(cpu_gdt, cpu);
+ gdt_descr.address = (unsigned long)per_cpu(gdt_page, cpu).gdt;
gdt_descr.size = GDT_SIZE - 1;
load_gdt(&gdt_descr);
diff -r 576929b5b43f arch/i386/kernel/entry.S
--- a/arch/i386/kernel/entry.S Tue Mar 06 16:28:38 2007 +1100
+++ b/arch/i386/kernel/entry.S Tue Mar 06 16:47:11 2007 +1100
@@ -561,7 +561,7 @@ 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; \
diff -r 576929b5b43f arch/i386/kernel/head.S
--- a/arch/i386/kernel/head.S Tue Mar 06 16:28:38 2007 +1100
+++ b/arch/i386/kernel/head.S Tue Mar 06 16:47:11 2007 +1100
@@ -592,7 +592,7 @@ ENTRY(early_gdt_descr)
.long boot_gdt_table
/* The boot Global Descriptor Table: after boot we allocate a per-cpu copy */
- .align L1_CACHE_BYTES
+ .p2align PAGE_SHIFT
ENTRY(boot_gdt_table)
.quad 0x0000000000000000 /* NULL descriptor */
.quad 0x0000000000000000 /* 0x0b reserved */
diff -r 576929b5b43f arch/i386/kernel/traps.c
--- a/arch/i386/kernel/traps.c Tue Mar 06 16:28:38 2007 +1100
+++ b/arch/i386/kernel/traps.c Tue Mar 06 16:28:40 2007 +1100
@@ -1018,7 +1018,7 @@ fastcall unsigned long patch_espfix_desc
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;
diff -r 576929b5b43f include/asm-i386/desc.h
--- a/include/asm-i386/desc.h Tue Mar 06 16:28:38 2007 +1100
+++ b/include/asm-i386/desc.h Tue Mar 06 16:47:22 2007 +1100
@@ -13,7 +13,11 @@
#include <asm/mmu.h>
extern struct desc_struct boot_gdt_table[GDT_ENTRIES];
-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);
struct Xgt_desc_struct {
unsigned short size;
@@ -24,7 +28,7 @@ extern struct Xgt_desc_struct idt_descr;
extern struct Xgt_desc_struct idt_descr;
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 desc_struct idt_table[];
@@ -104,7 +108,8 @@ static inline fastcall void native_set_l
pack_descriptor(&a, &b, (unsigned long)addr,
entries * sizeof(struct desc_struct) - 1,
DESCTYPE_LDT, 0);
- write_gdt_entry(__get_cpu_var(cpu_gdt), GDT_ENTRY_LDT, a, b);
+ write_gdt_entry(__get_cpu_var(gdt_page).gdt, GDT_ENTRY_LDT,
+ a, b);
__asm__ __volatile__("lldt %w0"::"q" (GDT_ENTRY_LDT*8));
}
}
-
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