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593309423c
Make the doublefault exception handler unconditional on 32-bit. Yes, it is important to be able to catch #DF exceptions instead of silent reboots. Yes, the code size increase is worth every byte. And one less CONFIG symbol is just the cherry on top. No functional changes. Signed-off-by: Borislav Petkov <bp@suse.de> Acked-by: Andy Lutomirski <luto@kernel.org> Link: https://lkml.kernel.org/r/20200404083646.8897-1-bp@alien8.de
155 lines
3.5 KiB
C
155 lines
3.5 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright (C) 1991, 1992 Linus Torvalds
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* Copyright (C) 2000, 2001, 2002 Andi Kleen, SuSE Labs
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*/
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#include <linux/sched/debug.h>
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#include <linux/kallsyms.h>
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#include <linux/kprobes.h>
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#include <linux/uaccess.h>
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#include <linux/hardirq.h>
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#include <linux/kdebug.h>
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#include <linux/export.h>
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#include <linux/ptrace.h>
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#include <linux/kexec.h>
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#include <linux/sysfs.h>
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#include <linux/bug.h>
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#include <linux/nmi.h>
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#include <asm/stacktrace.h>
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const char *stack_type_name(enum stack_type type)
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{
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if (type == STACK_TYPE_IRQ)
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return "IRQ";
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if (type == STACK_TYPE_SOFTIRQ)
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return "SOFTIRQ";
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if (type == STACK_TYPE_ENTRY)
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return "ENTRY_TRAMPOLINE";
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if (type == STACK_TYPE_EXCEPTION)
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return "#DF";
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return NULL;
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}
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static bool in_hardirq_stack(unsigned long *stack, struct stack_info *info)
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{
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unsigned long *begin = (unsigned long *)this_cpu_read(hardirq_stack_ptr);
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unsigned long *end = begin + (THREAD_SIZE / sizeof(long));
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/*
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* This is a software stack, so 'end' can be a valid stack pointer.
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* It just means the stack is empty.
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*/
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if (stack < begin || stack > end)
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return false;
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info->type = STACK_TYPE_IRQ;
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info->begin = begin;
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info->end = end;
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/*
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* See irq_32.c -- the next stack pointer is stored at the beginning of
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* the stack.
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*/
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info->next_sp = (unsigned long *)*begin;
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return true;
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}
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static bool in_softirq_stack(unsigned long *stack, struct stack_info *info)
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{
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unsigned long *begin = (unsigned long *)this_cpu_read(softirq_stack_ptr);
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unsigned long *end = begin + (THREAD_SIZE / sizeof(long));
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/*
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* This is a software stack, so 'end' can be a valid stack pointer.
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* It just means the stack is empty.
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*/
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if (stack < begin || stack > end)
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return false;
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info->type = STACK_TYPE_SOFTIRQ;
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info->begin = begin;
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info->end = end;
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/*
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* The next stack pointer is stored at the beginning of the stack.
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* See irq_32.c.
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*/
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info->next_sp = (unsigned long *)*begin;
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return true;
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}
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static bool in_doublefault_stack(unsigned long *stack, struct stack_info *info)
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{
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struct cpu_entry_area *cea = get_cpu_entry_area(raw_smp_processor_id());
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struct doublefault_stack *ss = &cea->doublefault_stack;
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void *begin = ss->stack;
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void *end = begin + sizeof(ss->stack);
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if ((void *)stack < begin || (void *)stack >= end)
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return false;
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info->type = STACK_TYPE_EXCEPTION;
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info->begin = begin;
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info->end = end;
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info->next_sp = (unsigned long *)this_cpu_read(cpu_tss_rw.x86_tss.sp);
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return true;
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}
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int get_stack_info(unsigned long *stack, struct task_struct *task,
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struct stack_info *info, unsigned long *visit_mask)
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{
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if (!stack)
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goto unknown;
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task = task ? : current;
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if (in_task_stack(stack, task, info))
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goto recursion_check;
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if (task != current)
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goto unknown;
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if (in_entry_stack(stack, info))
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goto recursion_check;
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if (in_hardirq_stack(stack, info))
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goto recursion_check;
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if (in_softirq_stack(stack, info))
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goto recursion_check;
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if (in_doublefault_stack(stack, info))
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goto recursion_check;
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goto unknown;
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recursion_check:
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/*
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* Make sure we don't iterate through any given stack more than once.
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* If it comes up a second time then there's something wrong going on:
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* just break out and report an unknown stack type.
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*/
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if (visit_mask) {
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if (*visit_mask & (1UL << info->type)) {
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printk_deferred_once(KERN_WARNING "WARNING: stack recursion on stack type %d\n", info->type);
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goto unknown;
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}
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*visit_mask |= 1UL << info->type;
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}
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return 0;
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unknown:
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info->type = STACK_TYPE_UNKNOWN;
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return -EINVAL;
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}
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