[PATCH] i386: cleanup GDT Access
Now we have an explicit per-cpu GDT variable, we don't need to keep the descriptors around to use them to find the GDT: expose cpu_gdt directly. We could go further and make load_gdt() pack the descriptor for us, or even assume it means "load the current cpu's GDT" which is what it always does. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Andi Kleen <ak@suse.de> Cc: Andi Kleen <ak@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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@ -22,9 +22,6 @@
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#include "cpu.h"
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DEFINE_PER_CPU(struct Xgt_desc_struct, cpu_gdt_descr);
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EXPORT_PER_CPU_SYMBOL(cpu_gdt_descr);
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DEFINE_PER_CPU(struct desc_struct, cpu_gdt[GDT_ENTRIES]) = {
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[GDT_ENTRY_KERNEL_CS] = { 0x0000ffff, 0x00cf9a00 },
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[GDT_ENTRY_KERNEL_DS] = { 0x0000ffff, 0x00cf9200 },
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@ -52,6 +49,7 @@ DEFINE_PER_CPU(struct desc_struct, cpu_gdt[GDT_ENTRIES]) = {
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[GDT_ENTRY_ESPFIX_SS] = { 0x00000000, 0x00c09200 },
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[GDT_ENTRY_PDA] = { 0x00000000, 0x00c09200 }, /* set in setup_pda */
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};
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EXPORT_PER_CPU_SYMBOL_GPL(cpu_gdt);
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DEFINE_PER_CPU(struct i386_pda, _cpu_pda);
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EXPORT_PER_CPU_SYMBOL(_cpu_pda);
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@ -69,13 +69,11 @@ static void efi_call_phys_prelog(void) __acquires(efi_rt_lock)
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{
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unsigned long cr4;
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unsigned long temp;
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struct Xgt_desc_struct *cpu_gdt_descr;
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struct Xgt_desc_struct gdt_descr;
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spin_lock(&efi_rt_lock);
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local_irq_save(efi_rt_eflags);
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cpu_gdt_descr = &per_cpu(cpu_gdt_descr, 0);
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/*
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* If I don't have PSE, I should just duplicate two entries in page
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* directory. If I have PSE, I just need to duplicate one entry in
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@ -105,17 +103,19 @@ static void efi_call_phys_prelog(void) __acquires(efi_rt_lock)
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*/
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local_flush_tlb();
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cpu_gdt_descr->address = __pa(cpu_gdt_descr->address);
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load_gdt(cpu_gdt_descr);
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gdt_descr.address = __pa(get_cpu_gdt_table(0));
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gdt_descr.size = GDT_SIZE - 1;
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load_gdt(&gdt_descr);
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}
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static void efi_call_phys_epilog(void) __releases(efi_rt_lock)
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{
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unsigned long cr4;
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struct Xgt_desc_struct *cpu_gdt_descr = &per_cpu(cpu_gdt_descr, 0);
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struct Xgt_desc_struct gdt_descr;
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cpu_gdt_descr->address = (unsigned long)__va(cpu_gdt_descr->address);
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load_gdt(cpu_gdt_descr);
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gdt_descr.address = (unsigned long)get_cpu_gdt_table(0);
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gdt_descr.size = GDT_SIZE - 1;
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load_gdt(&gdt_descr);
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cr4 = read_cr4();
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@ -561,8 +561,7 @@ END(syscall_badsys)
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#define FIXUP_ESPFIX_STACK \
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/* since we are on a wrong stack, we cant make it a C code :( */ \
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movl %fs:PDA_cpu, %ebx; \
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PER_CPU(cpu_gdt_descr, %ebx); \
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movl GDS_address(%ebx), %ebx; \
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PER_CPU(cpu_gdt, %ebx); \
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GET_DESC_BASE(GDT_ENTRY_ESPFIX_SS, %ebx, %eax, %ax, %al, %ah); \
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addl %esp, %eax; \
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pushl $__KERNEL_DS; \
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@ -786,13 +786,9 @@ static inline struct task_struct * alloc_idle_task(int cpu)
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secondary which will soon come up. */
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static __cpuinit void init_gdt(int cpu, struct task_struct *idle)
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{
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struct Xgt_desc_struct *cpu_gdt_descr = &per_cpu(cpu_gdt_descr, cpu);
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struct desc_struct *gdt = per_cpu(cpu_gdt, cpu);
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struct desc_struct *gdt = get_cpu_gdt_table(cpu);
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struct i386_pda *pda = &per_cpu(_cpu_pda, cpu);
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cpu_gdt_descr->address = (unsigned long)gdt;
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cpu_gdt_descr->size = GDT_SIZE - 1;
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pack_descriptor((u32 *)&gdt[GDT_ENTRY_PDA].a,
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(u32 *)&gdt[GDT_ENTRY_PDA].b,
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(unsigned long)pda, sizeof(*pda) - 1,
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@ -1187,7 +1183,11 @@ void __init smp_prepare_cpus(unsigned int max_cpus)
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* it's on the real one. */
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static inline void switch_to_new_gdt(void)
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{
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load_gdt(&per_cpu(cpu_gdt_descr, smp_processor_id()));
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struct Xgt_desc_struct gdt_descr;
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gdt_descr.address = (long)get_cpu_gdt_table(smp_processor_id());
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gdt_descr.size = GDT_SIZE - 1;
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load_gdt(&gdt_descr);
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asm volatile ("mov %0, %%fs" : : "r" (__KERNEL_PDA) : "memory");
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}
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@ -1030,9 +1030,7 @@ fastcall void do_spurious_interrupt_bug(struct pt_regs * regs,
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fastcall unsigned long patch_espfix_desc(unsigned long uesp,
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unsigned long kesp)
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{
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int cpu = smp_processor_id();
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struct Xgt_desc_struct *cpu_gdt_descr = &per_cpu(cpu_gdt_descr, cpu);
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struct desc_struct *gdt = (struct desc_struct *)cpu_gdt_descr->address;
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struct desc_struct *gdt = __get_cpu_var(cpu_gdt);
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unsigned long base = (kesp - uesp) & -THREAD_SIZE;
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unsigned long new_kesp = kesp - base;
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unsigned long lim_pages = (new_kesp | (THREAD_SIZE - 1)) >> PAGE_SHIFT;
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@ -18,16 +18,13 @@ struct Xgt_desc_struct {
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unsigned short pad;
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} __attribute__ ((packed));
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extern struct Xgt_desc_struct idt_descr;
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DECLARE_PER_CPU(struct Xgt_desc_struct, cpu_gdt_descr);
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DECLARE_PER_CPU(struct desc_struct, cpu_gdt[GDT_ENTRIES]);
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extern struct Xgt_desc_struct early_gdt_descr;
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static inline struct desc_struct *get_cpu_gdt_table(unsigned int cpu)
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{
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return (struct desc_struct *)per_cpu(cpu_gdt_descr, cpu).address;
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return per_cpu(cpu_gdt, cpu);
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}
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extern struct Xgt_desc_struct idt_descr;
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extern struct desc_struct idt_table[];
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extern void set_intr_gate(unsigned int irq, void * addr);
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