diff options
Diffstat (limited to 'arch/x86/kernel/dumpstack_64.c')
| -rw-r--r-- | arch/x86/kernel/dumpstack_64.c | 221 |
1 files changed, 221 insertions, 0 deletions
diff --git a/arch/x86/kernel/dumpstack_64.c b/arch/x86/kernel/dumpstack_64.c new file mode 100644 index 0000000000..f05339fee7 --- /dev/null +++ b/arch/x86/kernel/dumpstack_64.c @@ -0,0 +1,221 @@ +// 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/cpu_entry_area.h> +#include <asm/stacktrace.h> + +static const char * const exception_stack_names[] = { + [ ESTACK_DF ] = "#DF", + [ ESTACK_NMI ] = "NMI", + [ ESTACK_DB ] = "#DB", + [ ESTACK_MCE ] = "#MC", + [ ESTACK_VC ] = "#VC", + [ ESTACK_VC2 ] = "#VC2", +}; + +const char *stack_type_name(enum stack_type type) +{ + BUILD_BUG_ON(N_EXCEPTION_STACKS != 6); + + if (type == STACK_TYPE_TASK) + return "TASK"; + + if (type == STACK_TYPE_IRQ) + return "IRQ"; + + if (type == STACK_TYPE_SOFTIRQ) + return "SOFTIRQ"; + + 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; +} + +/** + * struct estack_pages - Page descriptor for exception stacks + * @offs: Offset from the start of the exception stack area + * @size: Size of the exception stack + * @type: Type to store in the stack_info struct + */ +struct estack_pages { + u32 offs; + u16 size; + u16 type; +}; + +#define EPAGERANGE(st) \ + [PFN_DOWN(CEA_ESTACK_OFFS(st)) ... \ + PFN_DOWN(CEA_ESTACK_OFFS(st) + CEA_ESTACK_SIZE(st) - 1)] = { \ + .offs = CEA_ESTACK_OFFS(st), \ + .size = CEA_ESTACK_SIZE(st), \ + .type = STACK_TYPE_EXCEPTION + ESTACK_ ##st, } + +/* + * Array of exception stack page descriptors. If the stack is larger than + * PAGE_SIZE, all pages covering a particular stack will have the same + * info. The guard pages including the not mapped DB2 stack are zeroed + * out. + */ +static const +struct estack_pages estack_pages[CEA_ESTACK_PAGES] ____cacheline_aligned = { + EPAGERANGE(DF), + EPAGERANGE(NMI), + EPAGERANGE(DB), + EPAGERANGE(MCE), + EPAGERANGE(VC), + EPAGERANGE(VC2), +}; + +static __always_inline bool in_exception_stack(unsigned long *stack, struct stack_info *info) +{ + unsigned long begin, end, stk = (unsigned long)stack; + const struct estack_pages *ep; + struct pt_regs *regs; + unsigned int k; + + BUILD_BUG_ON(N_EXCEPTION_STACKS != 6); + + begin = (unsigned long)__this_cpu_read(cea_exception_stacks); + /* + * Handle the case where stack trace is collected _before_ + * cea_exception_stacks had been initialized. + */ + if (!begin) + return false; + + end = begin + sizeof(struct cea_exception_stacks); + /* Bail if @stack is outside the exception stack area. */ + if (stk < begin || stk >= end) + return false; + + /* Calc page offset from start of exception stacks */ + k = (stk - begin) >> PAGE_SHIFT; + /* Lookup the page descriptor */ + ep = &estack_pages[k]; + /* Guard page? */ + if (!ep->size) + return false; + + begin += (unsigned long)ep->offs; + end = begin + (unsigned long)ep->size; + regs = (struct pt_regs *)end - 1; + + info->type = ep->type; + info->begin = (unsigned long *)begin; + info->end = (unsigned long *)end; + info->next_sp = (unsigned long *)regs->sp; + return true; +} + +static __always_inline bool in_irq_stack(unsigned long *stack, struct stack_info *info) +{ + unsigned long *end = (unsigned long *)this_cpu_read(pcpu_hot.hardirq_stack_ptr); + unsigned long *begin; + + /* + * @end points directly to the top most stack entry to avoid a -8 + * adjustment in the stack switch hotpath. Adjust it back before + * calculating @begin. + */ + end++; + begin = end - (IRQ_STACK_SIZE / sizeof(long)); + + /* + * Due to the switching logic RSP can never be == @end because the + * final operation is 'popq %rsp' which means after that RSP points + * to the original stack and not to @end. + */ + if (stack < begin || stack >= end) + return false; + + info->type = STACK_TYPE_IRQ; + info->begin = begin; + info->end = end; + + /* + * The next stack pointer is stored at the top of the irq stack + * before switching to the irq stack. Actual stack entries are all + * below that. + */ + info->next_sp = (unsigned long *)*(end - 1); + + return true; +} + +bool noinstr get_stack_info_noinstr(unsigned long *stack, struct task_struct *task, + struct stack_info *info) +{ + if (in_task_stack(stack, task, info)) + return true; + + if (task != current) + return false; + + if (in_exception_stack(stack, info)) + return true; + + if (in_irq_stack(stack, info)) + return true; + + if (in_entry_stack(stack, info)) + return true; + + return false; +} + +int get_stack_info(unsigned long *stack, struct task_struct *task, + struct stack_info *info, unsigned long *visit_mask) +{ + task = task ? : current; + + if (!stack) + goto unknown; + + if (!get_stack_info_noinstr(stack, task, info)) + goto unknown; + + /* + * 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)) { + if (task == current) + 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; +} |