[mirror_ubuntu-eoan-kernel.git] / arch / x86 / kernel / doublefault.c

// SPDX-License-Identifier: GPL-2.0
#include <linux/mm.h>
#include <linux/sched.h>
#include <linux/sched/debug.h>
#include <linux/init_task.h>
#include <linux/fs.h>

#include <linux/uaccess.h>
#include <asm/pgtable.h>
#include <asm/processor.h>
#include <asm/desc.h>

#ifdef CONFIG_X86_32

#define DOUBLEFAULT_STACKSIZE (1024)
static unsigned long doublefault_stack[DOUBLEFAULT_STACKSIZE];
#define STACK_START (unsigned long)(doublefault_stack+DOUBLEFAULT_STACKSIZE)

#define ptr_ok(x) ((x) > PAGE_OFFSET && (x) < PAGE_OFFSET + MAXMEM)

static void doublefault_fn(void)
{
	struct desc_ptr gdt_desc = {0, 0};
	unsigned long gdt, tss;

	native_store_gdt(&gdt_desc);
	gdt = gdt_desc.address;

	printk(KERN_EMERG "PANIC: double fault, gdt at %08lx [%d bytes]\n", gdt, gdt_desc.size);

	if (ptr_ok(gdt)) {
		gdt += GDT_ENTRY_TSS << 3;
		tss = get_desc_base((struct desc_struct *)gdt);
		printk(KERN_EMERG "double fault, tss at %08lx\n", tss);

		if (ptr_ok(tss)) {
			struct x86_hw_tss *t = (struct x86_hw_tss *)tss;

			printk(KERN_EMERG "eip = %08lx, esp = %08lx\n",
			       t->ip, t->sp);

			printk(KERN_EMERG "eax = %08lx, ebx = %08lx, ecx = %08lx, edx = %08lx\n",
				t->ax, t->bx, t->cx, t->dx);
			printk(KERN_EMERG "esi = %08lx, edi = %08lx\n",
				t->si, t->di);
		}
	}

	for (;;)
		cpu_relax();
}

struct x86_hw_tss doublefault_tss __cacheline_aligned = {
	.sp0		= STACK_START,
	.ss0		= __KERNEL_DS,
	.ldt		= 0,
	.io_bitmap_base	= INVALID_IO_BITMAP_OFFSET,

	.ip		= (unsigned long) doublefault_fn,
	/* 0x2 bit is always set */
	.flags		= X86_EFLAGS_SF | 0x2,
	.sp		= STACK_START,
	.es		= __USER_DS,
	.cs		= __KERNEL_CS,
	.ss		= __KERNEL_DS,
	.ds		= __USER_DS,
	.fs		= __KERNEL_PERCPU,
#ifndef CONFIG_X86_32_LAZY_GS
	.gs		= __KERNEL_STACK_CANARY,
#endif

	.__cr3		= __pa_nodebug(swapper_pg_dir),
};

/* dummy for do_double_fault() call */
void df_debug(struct pt_regs *regs, long error_code) {}

#else /* !CONFIG_X86_32 */

void df_debug(struct pt_regs *regs, long error_code)
{
	pr_emerg("PANIC: double fault, error_code: 0x%lx\n", error_code);
	show_regs(regs);
	panic("Machine halted.");
}
#endif
Commit	Line	Data
b2441318	1	// SPDX-License-Identifier: GPL-2.0
1da177e4 LT	2	#include <linux/mm.h>
1da177e4 LT	3	#include <linux/sched.h>
b17b0153	4	#include <linux/sched/debug.h>
1da177e4 LT	5	#include <linux/init_task.h>
	6	#include <linux/fs.h>
	7
7c0f6ba6	8	#include <linux/uaccess.h>
1da177e4 LT	9	#include <asm/pgtable.h>
	10	#include <asm/processor.h>
	11	#include <asm/desc.h>
	12
4d067d8e BP	13	#ifdef CONFIG_X86_32
4d067d8e BP	14
1da177e4 LT	15	#define DOUBLEFAULT_STACKSIZE (1024)
	16	static unsigned long doublefault_stack[DOUBLEFAULT_STACKSIZE];
	17	#define STACK_START (unsigned long)(doublefault_stack+DOUBLEFAULT_STACKSIZE)
	18
3dab307e	19	#define ptr_ok(x) ((x) > PAGE_OFFSET && (x) < PAGE_OFFSET + MAXMEM)
1da177e4 LT	20
	21	static void doublefault_fn(void)
	22	{
6b68f01b	23	struct desc_ptr gdt_desc = {0, 0};
1da177e4 LT	24	unsigned long gdt, tss;
1da177e4 LT	25
357d1226	26	native_store_gdt(&gdt_desc);
1da177e4 LT	27	gdt = gdt_desc.address;
1da177e4 LT	28
3dab307e	29	printk(KERN_EMERG "PANIC: double fault, gdt at %08lx [%d bytes]\n", gdt, gdt_desc.size);
1da177e4 LT	30
	31	if (ptr_ok(gdt)) {
	32	gdt += GDT_ENTRY_TSS << 3;
254e0a6b	33	tss = get_desc_base((struct desc_struct *)gdt);
3dab307e	34	printk(KERN_EMERG "double fault, tss at %08lx\n", tss);
1da177e4 LT	35
1da177e4 LT	36	if (ptr_ok(tss)) {
ca241c75	37	struct x86_hw_tss t = (struct x86_hw_tss )tss;
1da177e4	38
faca6227 PA	39	printk(KERN_EMERG "eip = %08lx, esp = %08lx\n",
faca6227 PA	40	t->ip, t->sp);
1da177e4	41
3dab307e	42	printk(KERN_EMERG "eax = %08lx, ebx = %08lx, ecx = %08lx, edx = %08lx\n",
faca6227	43	t->ax, t->bx, t->cx, t->dx);
3dab307e	44	printk(KERN_EMERG "esi = %08lx, edi = %08lx\n",
faca6227	45	t->si, t->di);
1da177e4 LT	46	}
	47	}
	48
caad3c2a CE	49	for (;;)
caad3c2a CE	50	cpu_relax();
1da177e4 LT	51	}
1da177e4 LT	52
7fb983b4 AL	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,
5890f300 AL	68	#ifndef CONFIG_X86_32_LAZY_GS
	69	.gs = __KERNEL_STACK_CANARY,
	70	#endif
7fb983b4 AL	71
7fb983b4 AL	72	.__cr3 = __pa_nodebug(swapper_pg_dir),
1da177e4	73	};
4d067d8e BP	74
	75	/* dummy for do_double_fault() call */
	76	void df_debug(struct pt_regs *regs, long error_code) {}
	77
	78	#else /* !CONFIG_X86_32 */
	79
	80	void df_debug(struct pt_regs *regs, long error_code)
	81	{
	82	pr_emerg("PANIC: double fault, error_code: 0x%lx\n", error_code);
	83	show_regs(regs);
	84	panic("Machine halted.");
	85	}
	86	#endif