1 | // SPDX-License-Identifier: GPL-2.0 |
2 | #include <linux/mm.h> |
3 | #include <linux/sched.h> |
4 | #include <linux/sched/debug.h> |
5 | #include <linux/init_task.h> |
6 | #include <linux/fs.h> |
7 | |
8 | #include <linux/uaccess.h> |
9 | #include <asm/pgtable.h> |
10 | #include <asm/processor.h> |
11 | #include <asm/desc.h> |
12 | |
13 | #ifdef CONFIG_X86_32 |
14 | |
15 | #define DOUBLEFAULT_STACKSIZE (1024) |
16 | static unsigned long doublefault_stack[DOUBLEFAULT_STACKSIZE]; |
17 | #define STACK_START (unsigned long)(doublefault_stack+DOUBLEFAULT_STACKSIZE) |
18 | |
19 | #define ptr_ok(x) ((x) > PAGE_OFFSET && (x) < PAGE_OFFSET + MAXMEM) |
20 | |
21 | static void doublefault_fn(void) |
22 | { |
23 | struct desc_ptr gdt_desc = {0, 0}; |
24 | unsigned long gdt, tss; |
25 | |
26 | native_store_gdt(&gdt_desc); |
27 | gdt = gdt_desc.address; |
28 | |
29 | printk(KERN_EMERG "PANIC: double fault, gdt at %08lx [%d bytes]\n" , gdt, gdt_desc.size); |
30 | |
31 | if (ptr_ok(gdt)) { |
32 | gdt += GDT_ENTRY_TSS << 3; |
33 | tss = get_desc_base((struct desc_struct *)gdt); |
34 | printk(KERN_EMERG "double fault, tss at %08lx\n" , tss); |
35 | |
36 | if (ptr_ok(tss)) { |
37 | struct x86_hw_tss *t = (struct x86_hw_tss *)tss; |
38 | |
39 | printk(KERN_EMERG "eip = %08lx, esp = %08lx\n" , |
40 | t->ip, t->sp); |
41 | |
42 | printk(KERN_EMERG "eax = %08lx, ebx = %08lx, ecx = %08lx, edx = %08lx\n" , |
43 | t->ax, t->bx, t->cx, t->dx); |
44 | printk(KERN_EMERG "esi = %08lx, edi = %08lx\n" , |
45 | t->si, t->di); |
46 | } |
47 | } |
48 | |
49 | for (;;) |
50 | cpu_relax(); |
51 | } |
52 | |
53 | struct x86_hw_tss doublefault_tss __cacheline_aligned = { |
54 | .sp0 = STACK_START, |
55 | .ss0 = __KERNEL_DS, |
56 | .ldt = 0, |
57 | .io_bitmap_base = INVALID_IO_BITMAP_OFFSET, |
58 | |
59 | .ip = (unsigned long) doublefault_fn, |
60 | /* 0x2 bit is always set */ |
61 | .flags = X86_EFLAGS_SF | 0x2, |
62 | .sp = STACK_START, |
63 | .es = __USER_DS, |
64 | .cs = __KERNEL_CS, |
65 | .ss = __KERNEL_DS, |
66 | .ds = __USER_DS, |
67 | .fs = __KERNEL_PERCPU, |
68 | |
69 | .__cr3 = __pa_nodebug(swapper_pg_dir), |
70 | }; |
71 | |
72 | /* dummy for do_double_fault() call */ |
73 | void df_debug(struct pt_regs *regs, long error_code) {} |
74 | |
75 | #else /* !CONFIG_X86_32 */ |
76 | |
77 | void df_debug(struct pt_regs *regs, long error_code) |
78 | { |
79 | pr_emerg("PANIC: double fault, error_code: 0x%lx\n" , error_code); |
80 | show_regs(regs); |
81 | panic("Machine halted." ); |
82 | } |
83 | #endif |
84 | |