x86_64: split out dumpstack code from traps_64.c
The dumpstack code is logically quite independent from the
hardware traps. Split it out into its own file.
Signed-off-by: Alexander van Heukelum <heukelum@fastmail.fm>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/arch/x86/kernel/dumpstack_64.c b/arch/x86/kernel/dumpstack_64.c
new file mode 100644
index 0000000..6f15050
--- /dev/null
+++ b/arch/x86/kernel/dumpstack_64.c
@@ -0,0 +1,565 @@
+/*
+ * Copyright (C) 1991, 1992 Linus Torvalds
+ * Copyright (C) 2000, 2001, 2002 Andi Kleen, SuSE Labs
+ */
+#include <linux/kallsyms.h>
+#include <linux/kprobes.h>
+#include <linux/uaccess.h>
+#include <linux/utsname.h>
+#include <linux/hardirq.h>
+#include <linux/kdebug.h>
+#include <linux/module.h>
+#include <linux/ptrace.h>
+#include <linux/kexec.h>
+#include <linux/bug.h>
+#include <linux/nmi.h>
+
+#include <asm/stacktrace.h>
+
+int panic_on_unrecovered_nmi;
+int kstack_depth_to_print = 12;
+static unsigned int code_bytes = 64;
+static int die_counter;
+
+void printk_address(unsigned long address, int reliable)
+{
+ printk(" [<%016lx>] %s%pS\n",
+ address, reliable ? "" : "? ", (void *) address);
+}
+
+static unsigned long *in_exception_stack(unsigned cpu, unsigned long stack,
+ unsigned *usedp, char **idp)
+{
+ static char ids[][8] = {
+ [DEBUG_STACK - 1] = "#DB",
+ [NMI_STACK - 1] = "NMI",
+ [DOUBLEFAULT_STACK - 1] = "#DF",
+ [STACKFAULT_STACK - 1] = "#SS",
+ [MCE_STACK - 1] = "#MC",
+#if DEBUG_STKSZ > EXCEPTION_STKSZ
+ [N_EXCEPTION_STACKS ...
+ N_EXCEPTION_STACKS + DEBUG_STKSZ / EXCEPTION_STKSZ - 2] = "#DB[?]"
+#endif
+ };
+ unsigned k;
+
+ /*
+ * Iterate over all exception stacks, and figure out whether
+ * 'stack' is in one of them:
+ */
+ for (k = 0; k < N_EXCEPTION_STACKS; k++) {
+ unsigned long end = per_cpu(orig_ist, cpu).ist[k];
+ /*
+ * Is 'stack' above this exception frame's end?
+ * If yes then skip to the next frame.
+ */
+ if (stack >= end)
+ continue;
+ /*
+ * Is 'stack' above this exception frame's start address?
+ * If yes then we found the right frame.
+ */
+ if (stack >= end - EXCEPTION_STKSZ) {
+ /*
+ * Make sure we only iterate through an exception
+ * stack once. If it comes up for the second time
+ * then there's something wrong going on - just
+ * break out and return NULL:
+ */
+ if (*usedp & (1U << k))
+ break;
+ *usedp |= 1U << k;
+ *idp = ids[k];
+ return (unsigned long *)end;
+ }
+ /*
+ * If this is a debug stack, and if it has a larger size than
+ * the usual exception stacks, then 'stack' might still
+ * be within the lower portion of the debug stack:
+ */
+#if DEBUG_STKSZ > EXCEPTION_STKSZ
+ if (k == DEBUG_STACK - 1 && stack >= end - DEBUG_STKSZ) {
+ unsigned j = N_EXCEPTION_STACKS - 1;
+
+ /*
+ * Black magic. A large debug stack is composed of
+ * multiple exception stack entries, which we
+ * iterate through now. Dont look:
+ */
+ do {
+ ++j;
+ end -= EXCEPTION_STKSZ;
+ ids[j][4] = '1' + (j - N_EXCEPTION_STACKS);
+ } while (stack < end - EXCEPTION_STKSZ);
+ if (*usedp & (1U << j))
+ break;
+ *usedp |= 1U << j;
+ *idp = ids[j];
+ return (unsigned long *)end;
+ }
+#endif
+ }
+ return NULL;
+}
+
+/*
+ * x86-64 can have up to three kernel stacks:
+ * process stack
+ * interrupt stack
+ * severe exception (double fault, nmi, stack fault, debug, mce) hardware stack
+ */
+
+static inline int valid_stack_ptr(struct thread_info *tinfo,
+ void *p, unsigned int size, void *end)
+{
+ void *t = tinfo;
+ if (end) {
+ if (p < end && p >= (end-THREAD_SIZE))
+ return 1;
+ else
+ return 0;
+ }
+ return p > t && p < t + THREAD_SIZE - size;
+}
+
+/* The form of the top of the frame on the stack */
+struct stack_frame {
+ struct stack_frame *next_frame;
+ unsigned long return_address;
+};
+
+static inline unsigned long
+print_context_stack(struct thread_info *tinfo,
+ unsigned long *stack, unsigned long bp,
+ const struct stacktrace_ops *ops, void *data,
+ unsigned long *end)
+{
+ struct stack_frame *frame = (struct stack_frame *)bp;
+
+ while (valid_stack_ptr(tinfo, stack, sizeof(*stack), end)) {
+ unsigned long addr;
+
+ addr = *stack;
+ if (__kernel_text_address(addr)) {
+ if ((unsigned long) stack == bp + 8) {
+ ops->address(data, addr, 1);
+ frame = frame->next_frame;
+ bp = (unsigned long) frame;
+ } else {
+ ops->address(data, addr, bp == 0);
+ }
+ }
+ stack++;
+ }
+ return bp;
+}
+
+void dump_trace(struct task_struct *task, struct pt_regs *regs,
+ unsigned long *stack, unsigned long bp,
+ const struct stacktrace_ops *ops, void *data)
+{
+ const unsigned cpu = get_cpu();
+ unsigned long *irqstack_end = (unsigned long *)cpu_pda(cpu)->irqstackptr;
+ unsigned used = 0;
+ struct thread_info *tinfo;
+
+ if (!task)
+ task = current;
+
+ if (!stack) {
+ unsigned long dummy;
+ stack = &dummy;
+ if (task && task != current)
+ stack = (unsigned long *)task->thread.sp;
+ }
+
+#ifdef CONFIG_FRAME_POINTER
+ if (!bp) {
+ if (task == current) {
+ /* Grab bp right from our regs */
+ asm("movq %%rbp, %0" : "=r" (bp) : );
+ } else {
+ /* bp is the last reg pushed by switch_to */
+ bp = *(unsigned long *) task->thread.sp;
+ }
+ }
+#endif
+
+ /*
+ * Print function call entries in all stacks, starting at the
+ * current stack address. If the stacks consist of nested
+ * exceptions
+ */
+ tinfo = task_thread_info(task);
+ for (;;) {
+ char *id;
+ unsigned long *estack_end;
+ estack_end = in_exception_stack(cpu, (unsigned long)stack,
+ &used, &id);
+
+ if (estack_end) {
+ if (ops->stack(data, id) < 0)
+ break;
+
+ bp = print_context_stack(tinfo, stack, bp, ops,
+ data, estack_end);
+ ops->stack(data, "<EOE>");
+ /*
+ * We link to the next stack via the
+ * second-to-last pointer (index -2 to end) in the
+ * exception stack:
+ */
+ stack = (unsigned long *) estack_end[-2];
+ continue;
+ }
+ if (irqstack_end) {
+ unsigned long *irqstack;
+ irqstack = irqstack_end -
+ (IRQSTACKSIZE - 64) / sizeof(*irqstack);
+
+ if (stack >= irqstack && stack < irqstack_end) {
+ if (ops->stack(data, "IRQ") < 0)
+ break;
+ bp = print_context_stack(tinfo, stack, bp,
+ ops, data, irqstack_end);
+ /*
+ * We link to the next stack (which would be
+ * the process stack normally) the last
+ * pointer (index -1 to end) in the IRQ stack:
+ */
+ stack = (unsigned long *) (irqstack_end[-1]);
+ irqstack_end = NULL;
+ ops->stack(data, "EOI");
+ continue;
+ }
+ }
+ break;
+ }
+
+ /*
+ * This handles the process stack:
+ */
+ bp = print_context_stack(tinfo, stack, bp, ops, data, NULL);
+ put_cpu();
+}
+EXPORT_SYMBOL(dump_trace);
+
+static void
+print_trace_warning_symbol(void *data, char *msg, unsigned long symbol)
+{
+ print_symbol(msg, symbol);
+ printk("\n");
+}
+
+static void print_trace_warning(void *data, char *msg)
+{
+ printk("%s\n", msg);
+}
+
+static int print_trace_stack(void *data, char *name)
+{
+ printk(" <%s> ", name);
+ return 0;
+}
+
+static void print_trace_address(void *data, unsigned long addr, int reliable)
+{
+ touch_nmi_watchdog();
+ printk_address(addr, reliable);
+}
+
+static const struct stacktrace_ops print_trace_ops = {
+ .warning = print_trace_warning,
+ .warning_symbol = print_trace_warning_symbol,
+ .stack = print_trace_stack,
+ .address = print_trace_address,
+};
+
+static void
+show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs,
+ unsigned long *stack, unsigned long bp, char *log_lvl)
+{
+ printk("Call Trace:\n");
+ dump_trace(task, regs, stack, bp, &print_trace_ops, log_lvl);
+}
+
+void show_trace(struct task_struct *task, struct pt_regs *regs,
+ unsigned long *stack, unsigned long bp)
+{
+ show_trace_log_lvl(task, regs, stack, bp, "");
+}
+
+static void
+show_stack_log_lvl(struct task_struct *task, struct pt_regs *regs,
+ unsigned long *sp, unsigned long bp, char *log_lvl)
+{
+ unsigned long *stack;
+ int i;
+ const int cpu = smp_processor_id();
+ unsigned long *irqstack_end =
+ (unsigned long *) (cpu_pda(cpu)->irqstackptr);
+ unsigned long *irqstack =
+ (unsigned long *) (cpu_pda(cpu)->irqstackptr - IRQSTACKSIZE);
+
+ /*
+ * debugging aid: "show_stack(NULL, NULL);" prints the
+ * back trace for this cpu.
+ */
+
+ if (sp == NULL) {
+ if (task)
+ sp = (unsigned long *)task->thread.sp;
+ else
+ sp = (unsigned long *)&sp;
+ }
+
+ stack = sp;
+ for (i = 0; i < kstack_depth_to_print; i++) {
+ if (stack >= irqstack && stack <= irqstack_end) {
+ if (stack == irqstack_end) {
+ stack = (unsigned long *) (irqstack_end[-1]);
+ printk(" <EOI> ");
+ }
+ } else {
+ if (((long) stack & (THREAD_SIZE-1)) == 0)
+ break;
+ }
+ if (i && ((i % 4) == 0))
+ printk("\n");
+ printk(" %016lx", *stack++);
+ touch_nmi_watchdog();
+ }
+ printk("\n");
+ show_trace_log_lvl(task, regs, sp, bp, log_lvl);
+}
+
+void show_stack(struct task_struct *task, unsigned long *sp)
+{
+ show_stack_log_lvl(task, NULL, sp, 0, "");
+}
+
+/*
+ * The architecture-independent dump_stack generator
+ */
+void dump_stack(void)
+{
+ unsigned long bp = 0;
+ unsigned long stack;
+
+#ifdef CONFIG_FRAME_POINTER
+ if (!bp)
+ asm("movq %%rbp, %0" : "=r" (bp) : );
+#endif
+
+ printk("Pid: %d, comm: %.20s %s %s %.*s\n",
+ current->pid, current->comm, print_tainted(),
+ init_utsname()->release,
+ (int)strcspn(init_utsname()->version, " "),
+ init_utsname()->version);
+ show_trace(NULL, NULL, &stack, bp);
+}
+EXPORT_SYMBOL(dump_stack);
+
+void show_registers(struct pt_regs *regs)
+{
+ int i;
+ unsigned long sp;
+ const int cpu = smp_processor_id();
+ struct task_struct *cur = cpu_pda(cpu)->pcurrent;
+
+ sp = regs->sp;
+ printk("CPU %d ", cpu);
+ __show_regs(regs, 1);
+ printk("Process %s (pid: %d, threadinfo %p, task %p)\n",
+ cur->comm, cur->pid, task_thread_info(cur), cur);
+
+ /*
+ * When in-kernel, we also print out the stack and code at the
+ * time of the fault..
+ */
+ if (!user_mode(regs)) {
+ unsigned int code_prologue = code_bytes * 43 / 64;
+ unsigned int code_len = code_bytes;
+ unsigned char c;
+ u8 *ip;
+
+ printk("Stack: ");
+ show_stack_log_lvl(NULL, regs, (unsigned long *)sp,
+ regs->bp, "");
+
+ printk(KERN_EMERG "Code: ");
+
+ ip = (u8 *)regs->ip - code_prologue;
+ if (ip < (u8 *)PAGE_OFFSET || probe_kernel_address(ip, c)) {
+ /* try starting at RIP */
+ ip = (u8 *)regs->ip;
+ code_len = code_len - code_prologue + 1;
+ }
+ for (i = 0; i < code_len; i++, ip++) {
+ if (ip < (u8 *)PAGE_OFFSET ||
+ probe_kernel_address(ip, c)) {
+ printk(" Bad RIP value.");
+ break;
+ }
+ if (ip == (u8 *)regs->ip)
+ printk("<%02x> ", c);
+ else
+ printk("%02x ", c);
+ }
+ }
+ printk("\n");
+}
+
+int is_valid_bugaddr(unsigned long ip)
+{
+ unsigned short ud2;
+
+ if (__copy_from_user(&ud2, (const void __user *) ip, sizeof(ud2)))
+ return 0;
+
+ return ud2 == 0x0b0f;
+}
+
+static raw_spinlock_t die_lock = __RAW_SPIN_LOCK_UNLOCKED;
+static int die_owner = -1;
+static unsigned int die_nest_count;
+
+unsigned __kprobes long oops_begin(void)
+{
+ int cpu;
+ unsigned long flags;
+
+ oops_enter();
+
+ /* racy, but better than risking deadlock. */
+ raw_local_irq_save(flags);
+ cpu = smp_processor_id();
+ if (!__raw_spin_trylock(&die_lock)) {
+ if (cpu == die_owner)
+ /* nested oops. should stop eventually */;
+ else
+ __raw_spin_lock(&die_lock);
+ }
+ die_nest_count++;
+ die_owner = cpu;
+ console_verbose();
+ bust_spinlocks(1);
+ return flags;
+}
+
+void __kprobes oops_end(unsigned long flags, struct pt_regs *regs, int signr)
+{
+ die_owner = -1;
+ bust_spinlocks(0);
+ die_nest_count--;
+ if (!die_nest_count)
+ /* Nest count reaches zero, release the lock. */
+ __raw_spin_unlock(&die_lock);
+ raw_local_irq_restore(flags);
+ if (!regs) {
+ oops_exit();
+ return;
+ }
+ if (in_interrupt())
+ panic("Fatal exception in interrupt");
+ if (panic_on_oops)
+ panic("Fatal exception");
+ oops_exit();
+ do_exit(signr);
+}
+
+int __kprobes __die(const char *str, struct pt_regs *regs, long err)
+{
+ printk(KERN_EMERG "%s: %04lx [%u] ", str, err & 0xffff, ++die_counter);
+#ifdef CONFIG_PREEMPT
+ printk("PREEMPT ");
+#endif
+#ifdef CONFIG_SMP
+ printk("SMP ");
+#endif
+#ifdef CONFIG_DEBUG_PAGEALLOC
+ printk("DEBUG_PAGEALLOC");
+#endif
+ printk("\n");
+ if (notify_die(DIE_OOPS, str, regs, err,
+ current->thread.trap_no, SIGSEGV) == NOTIFY_STOP)
+ return 1;
+
+ show_registers(regs);
+ add_taint(TAINT_DIE);
+ /* Executive summary in case the oops scrolled away */
+ printk(KERN_ALERT "RIP ");
+ printk_address(regs->ip, 1);
+ printk(" RSP <%016lx>\n", regs->sp);
+ if (kexec_should_crash(current))
+ crash_kexec(regs);
+ return 0;
+}
+
+void die(const char *str, struct pt_regs *regs, long err)
+{
+ unsigned long flags = oops_begin();
+
+ if (!user_mode(regs))
+ report_bug(regs->ip, regs);
+
+ if (__die(str, regs, err))
+ regs = NULL;
+ oops_end(flags, regs, SIGSEGV);
+}
+
+notrace __kprobes void
+die_nmi(char *str, struct pt_regs *regs, int do_panic)
+{
+ unsigned long flags;
+
+ if (notify_die(DIE_NMIWATCHDOG, str, regs, 0, 2, SIGINT) == NOTIFY_STOP)
+ return;
+
+ flags = oops_begin();
+ /*
+ * We are in trouble anyway, lets at least try
+ * to get a message out.
+ */
+ printk(KERN_EMERG "%s", str);
+ printk(" on CPU%d, ip %08lx, registers:\n",
+ smp_processor_id(), regs->ip);
+ show_registers(regs);
+ if (kexec_should_crash(current))
+ crash_kexec(regs);
+ if (do_panic || panic_on_oops)
+ panic("Non maskable interrupt");
+ oops_end(flags, NULL, SIGBUS);
+ nmi_exit();
+ local_irq_enable();
+ do_exit(SIGBUS);
+}
+
+static int __init oops_setup(char *s)
+{
+ if (!s)
+ return -EINVAL;
+ if (!strcmp(s, "panic"))
+ panic_on_oops = 1;
+ return 0;
+}
+early_param("oops", oops_setup);
+
+static int __init kstack_setup(char *s)
+{
+ if (!s)
+ return -EINVAL;
+ kstack_depth_to_print = simple_strtoul(s, NULL, 0);
+ return 0;
+}
+early_param("kstack", kstack_setup);
+
+static int __init code_bytes_setup(char *s)
+{
+ code_bytes = simple_strtoul(s, NULL, 0);
+ if (code_bytes > 8192)
+ code_bytes = 8192;
+
+ return 1;
+}
+__setup("code_bytes=", code_bytes_setup);