From 7c4cb60e5b97677424e95baee9c29df54b26e6ba Mon Sep 17 00:00:00 2001 From: Zachary Amsden Date: Fri, 6 Jan 2006 00:11:47 -0800 Subject: [PATCH] x86: GDT alignment fix Make GDT page aligned and page padded to support running inside of a hypervisor. This prevents false sharing of the GDT page with other hot data, which is not allowed in Xen, and causes performance problems in VMware. Rather than go back to the old method of statically allocating the GDT (which wastes unneded space for non-present CPUs), the GDT for APs is allocated dynamically. Signed-off-by: Zachary Amsden Cc: "Seth, Rohit" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/asm-i386/desc.h | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) (limited to 'include/asm-i386/desc.h') diff --git a/include/asm-i386/desc.h b/include/asm-i386/desc.h index 29b851a18c6..494e73bca09 100644 --- a/include/asm-i386/desc.h +++ b/include/asm-i386/desc.h @@ -15,9 +15,6 @@ #include extern struct desc_struct cpu_gdt_table[GDT_ENTRIES]; -DECLARE_PER_CPU(struct desc_struct, cpu_gdt_table[GDT_ENTRIES]); - -#define get_cpu_gdt_table(_cpu) (per_cpu(cpu_gdt_table,_cpu)) DECLARE_PER_CPU(unsigned char, cpu_16bit_stack[CPU_16BIT_STACK_SIZE]); @@ -29,6 +26,11 @@ struct Xgt_desc_struct { extern struct Xgt_desc_struct idt_descr, cpu_gdt_descr[NR_CPUS]; +static inline struct desc_struct *get_cpu_gdt_table(unsigned int cpu) +{ + return ((struct desc_struct *)cpu_gdt_descr[cpu].address); +} + #define load_TR_desc() __asm__ __volatile__("ltr %w0"::"q" (GDT_ENTRY_TSS*8)) #define load_LDT_desc() __asm__ __volatile__("lldt %w0"::"q" (GDT_ENTRY_LDT*8)) -- cgit v1.2.2