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-rw-r--r--arch/x86/kernel/dumpstack_64.c221
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 000000000..6c5defd65
--- /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(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;
+}