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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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