4d37e7e3fd
i386 inline assembler cleanup. This change encapsulates descriptor and task register management. Also, it is possible to improve assembler generation in two cases; savesegment may store the value in a register instead of a memory location, which allows GCC to optimize stack variables into registers, and MOV MEM, SEG is always a 16-bit write to memory, making the casting in math-emu unnecessary. Signed-off-by: Zachary Amsden <zach@vmware.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
65 lines
1.6 KiB
C
65 lines
1.6 KiB
C
#include <linux/mm.h>
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#include <linux/sched.h>
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#include <linux/init.h>
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#include <linux/init_task.h>
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#include <linux/fs.h>
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#include <asm/uaccess.h>
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#include <asm/pgtable.h>
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#include <asm/processor.h>
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#include <asm/desc.h>
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#define DOUBLEFAULT_STACKSIZE (1024)
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static unsigned long doublefault_stack[DOUBLEFAULT_STACKSIZE];
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#define STACK_START (unsigned long)(doublefault_stack+DOUBLEFAULT_STACKSIZE)
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#define ptr_ok(x) ((x) > PAGE_OFFSET && (x) < PAGE_OFFSET + 0x1000000)
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static void doublefault_fn(void)
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{
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struct Xgt_desc_struct gdt_desc = {0, 0};
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unsigned long gdt, tss;
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store_gdt(&gdt_desc);
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gdt = gdt_desc.address;
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printk("double fault, gdt at %08lx [%d bytes]\n", gdt, gdt_desc.size);
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if (ptr_ok(gdt)) {
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gdt += GDT_ENTRY_TSS << 3;
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tss = *(u16 *)(gdt+2);
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tss += *(u8 *)(gdt+4) << 16;
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tss += *(u8 *)(gdt+7) << 24;
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printk("double fault, tss at %08lx\n", tss);
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if (ptr_ok(tss)) {
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struct tss_struct *t = (struct tss_struct *)tss;
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printk("eip = %08lx, esp = %08lx\n", t->eip, t->esp);
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printk("eax = %08lx, ebx = %08lx, ecx = %08lx, edx = %08lx\n",
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t->eax, t->ebx, t->ecx, t->edx);
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printk("esi = %08lx, edi = %08lx\n",
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t->esi, t->edi);
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}
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}
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for (;;) /* nothing */;
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}
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struct tss_struct doublefault_tss __cacheline_aligned = {
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.esp0 = STACK_START,
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.ss0 = __KERNEL_DS,
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.ldt = 0,
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.io_bitmap_base = INVALID_IO_BITMAP_OFFSET,
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.eip = (unsigned long) doublefault_fn,
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.eflags = X86_EFLAGS_SF | 0x2, /* 0x2 bit is always set */
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.esp = STACK_START,
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.es = __USER_DS,
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.cs = __KERNEL_CS,
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.ss = __KERNEL_DS,
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.ds = __USER_DS,
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.__cr3 = __pa(swapper_pg_dir)
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};
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