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- // SPDX-License-Identifier: GPL-2.0
- /*
- * Copyright (C) 1991, 1992 Linus Torvalds
- * Copyright (C) 2000, 2001, 2002 Andi Kleen, SuSE Labs
- */
- #include <linux/sched/debug.h>
- #include <linux/kallsyms.h>
- #include <linux/kprobes.h>
- #include <linux/uaccess.h>
- #include <linux/hardirq.h>
- #include <linux/kdebug.h>
- #include <linux/export.h>
- #include <linux/ptrace.h>
- #include <linux/kexec.h>
- #include <linux/sysfs.h>
- #include <linux/bug.h>
- #include <linux/nmi.h>
- #include <asm/stacktrace.h>
- static char *exception_stack_names[N_EXCEPTION_STACKS] = {
- [ DOUBLEFAULT_STACK-1 ] = "#DF",
- [ NMI_STACK-1 ] = "NMI",
- [ DEBUG_STACK-1 ] = "#DB",
- [ MCE_STACK-1 ] = "#MC",
- };
- static unsigned long exception_stack_sizes[N_EXCEPTION_STACKS] = {
- [0 ... N_EXCEPTION_STACKS - 1] = EXCEPTION_STKSZ,
- [DEBUG_STACK - 1] = DEBUG_STKSZ
- };
- const char *stack_type_name(enum stack_type type)
- {
- BUILD_BUG_ON(N_EXCEPTION_STACKS != 4);
- if (type == STACK_TYPE_IRQ)
- return "IRQ";
- if (type == STACK_TYPE_ENTRY) {
- /*
- * On 64-bit, we have a generic entry stack that we
- * use for all the kernel entry points, including
- * SYSENTER.
- */
- return "ENTRY_TRAMPOLINE";
- }
- if (type >= STACK_TYPE_EXCEPTION && type <= STACK_TYPE_EXCEPTION_LAST)
- return exception_stack_names[type - STACK_TYPE_EXCEPTION];
- return NULL;
- }
- static bool in_exception_stack(unsigned long *stack, struct stack_info *info)
- {
- unsigned long *begin, *end;
- struct pt_regs *regs;
- unsigned k;
- BUILD_BUG_ON(N_EXCEPTION_STACKS != 4);
- for (k = 0; k < N_EXCEPTION_STACKS; k++) {
- end = (unsigned long *)raw_cpu_ptr(&orig_ist)->ist[k];
- begin = end - (exception_stack_sizes[k] / sizeof(long));
- regs = (struct pt_regs *)end - 1;
- if (stack <= begin || stack >= end)
- continue;
- info->type = STACK_TYPE_EXCEPTION + k;
- info->begin = begin;
- info->end = end;
- info->next_sp = (unsigned long *)regs->sp;
- return true;
- }
- return false;
- }
- static bool in_irq_stack(unsigned long *stack, struct stack_info *info)
- {
- unsigned long *end = (unsigned long *)this_cpu_read(irq_stack_ptr);
- unsigned long *begin = end - (IRQ_STACK_SIZE / sizeof(long));
- /*
- * This is a software stack, so 'end' can be a valid stack pointer.
- * It just means the stack is empty.
- */
- if (stack <= begin || stack > end)
- return false;
- info->type = STACK_TYPE_IRQ;
- info->begin = begin;
- info->end = end;
- /*
- * The next stack pointer is the first thing pushed by the entry code
- * after switching to the irq stack.
- */
- info->next_sp = (unsigned long *)*(end - 1);
- return true;
- }
- int get_stack_info(unsigned long *stack, struct task_struct *task,
- struct stack_info *info, unsigned long *visit_mask)
- {
- if (!stack)
- goto unknown;
- task = task ? : current;
- if (in_task_stack(stack, task, info))
- goto recursion_check;
- if (task != current)
- goto unknown;
- if (in_exception_stack(stack, info))
- goto recursion_check;
- if (in_irq_stack(stack, info))
- goto recursion_check;
- if (in_entry_stack(stack, info))
- goto recursion_check;
- goto unknown;
- recursion_check:
- /*
- * Make sure we don't iterate through any given stack more than once.
- * If it comes up a second time then there's something wrong going on:
- * just break out and report an unknown stack type.
- */
- if (visit_mask) {
- if (*visit_mask & (1UL << info->type)) {
- printk_deferred_once(KERN_WARNING "WARNING: stack recursion on stack type %d\n", info->type);
- goto unknown;
- }
- *visit_mask |= 1UL << info->type;
- }
- return 0;
- unknown:
- info->type = STACK_TYPE_UNKNOWN;
- return -EINVAL;
- }
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