Messages in this thread Patch in this message | | | Subject | [PATCH 7/8] Page-align the GDT | From | Rusty Russell <> | Date | Wed, 07 Mar 2007 00:01:47 +1100 |
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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>
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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