i386: split out dumpstack code from traps_32.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>

1 files changed, 422 insertions, 0 deletions

diff --git a/arch/x86/kernel/dumpstack_32.c b/arch/x86/kernel/dumpstack_32.c
new file mode 100644
index 000000000000..c398b27df6cd
--- /dev/null
+++ b/arch/x86/kernel/dumpstack_32.c
@@ -0,0 +1,422 @@
+/*
+ *  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 = 24;
+static unsigned int code_bytes = 64;
+static int die_counter;
+
+void printk_address(unsigned long address, int reliable)
+{
+#ifdef CONFIG_KALLSYMS
+	unsigned long offset = 0;
+	unsigned long symsize;
+	const char *symname;
+	char *modname;
+	char *delim = ":";
+	char namebuf[KSYM_NAME_LEN];
+	char reliab[4] = "";
+
+	symname = kallsyms_lookup(address, &symsize, &offset,
+					&modname, namebuf);
+	if (!symname) {
+		printk(" [<%08lx>]\n", address);
+		return;
+	}
+	if (!reliable)
+		strcpy(reliab, "? ");
+
+	if (!modname)
+		modname = delim = "";
+	printk(" [<%08lx>] %s%s%s%s%s+0x%lx/0x%lx\n",
+		address, reliab, delim, modname, delim, symname, offset, symsize);
+#else
+	printk(" [<%08lx>]\n", address);
+#endif
+}
+
+static inline int valid_stack_ptr(struct thread_info *tinfo,
+			void *p, unsigned int size)
+{
+	void *t = tinfo;
+	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)
+{
+	struct stack_frame *frame = (struct stack_frame *)bp;
+
+	while (valid_stack_ptr(tinfo, stack, sizeof(*stack))) {
+		unsigned long addr;
+
+		addr = *stack;
+		if (__kernel_text_address(addr)) {
+			if ((unsigned long) stack == bp + 4) {
+				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)
+{
+	if (!task)
+		task = current;
+
+	if (!stack) {
+		unsigned long dummy;
+		stack = &dummy;
+		if (task != current)
+			stack = (unsigned long *)task->thread.sp;
+	}
+
+#ifdef CONFIG_FRAME_POINTER
+	if (!bp) {
+		if (task == current) {
+			/* Grab bp right from our regs */
+			asm("movl %%ebp, %0" : "=r" (bp) :);
+		} else {
+			/* bp is the last reg pushed by switch_to */
+			bp = *(unsigned long *) task->thread.sp;
+		}
+	}
+#endif
+
+	for (;;) {
+		struct thread_info *context;
+
+		context = (struct thread_info *)
+			((unsigned long)stack & (~(THREAD_SIZE - 1)));
+		bp = print_context_stack(context, stack, bp, ops, data);
+		/*
+		 * Should be after the line below, but somewhere
+		 * in early boot context comes out corrupted and we
+		 * can't reference it:
+		 */
+		if (ops->stack(data, "IRQ") < 0)
+			break;
+		stack = (unsigned long *)context->previous_esp;
+		if (!stack)
+			break;
+		touch_nmi_watchdog();
+	}
+}
+EXPORT_SYMBOL(dump_trace);
+
+static void
+print_trace_warning_symbol(void *data, char *msg, unsigned long symbol)
+{
+	printk(data);
+	print_symbol(msg, symbol);
+	printk("\n");
+}
+
+static void print_trace_warning(void *data, char *msg)
+{
+	printk("%s%s\n", (char *)data, msg);
+}
+
+static int print_trace_stack(void *data, char *name)
+{
+	return 0;
+}
+
+/*
+ * Print one address/symbol entries per line.
+ */
+static void print_trace_address(void *data, unsigned long addr, int reliable)
+{
+	printk("%s [<%08lx>] ", (char *)data, addr);
+	if (!reliable)
+		printk("? ");
+	print_symbol("%s\n", addr);
+	touch_nmi_watchdog();
+}
+
+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)
+{
+	dump_trace(task, regs, stack, bp, &print_trace_ops, log_lvl);
+	printk("%s =======================\n", 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;
+
+	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 (kstack_end(stack))
+			break;
+		if (i && ((i % 8) == 0))
+			printk("\n%s       ", log_lvl);
+		printk("%08lx ", *stack++);
+	}
+	printk("\n%sCall Trace:\n", log_lvl);
+
+	show_trace_log_lvl(task, regs, sp, bp, log_lvl);
+}
+
+void show_stack(struct task_struct *task, unsigned long *sp)
+{
+	printk("       ");
+	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("movl %%ebp, %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(current, NULL, &stack, bp);
+}
+
+EXPORT_SYMBOL(dump_stack);
+
+void show_registers(struct pt_regs *regs)
+{
+	int i;
+
+	print_modules();
+	__show_regs(regs, 0);
+
+	printk(KERN_EMERG "Process %.*s (pid: %d, ti=%p task=%p task.ti=%p)",
+		TASK_COMM_LEN, current->comm, task_pid_nr(current),
+		current_thread_info(), current, task_thread_info(current));
+	/*
+	 * When in-kernel, we also print out the stack and code at the
+	 * time of the fault..
+	 */
+	if (!user_mode_vm(regs)) {
+		unsigned int code_prologue = code_bytes * 43 / 64;
+		unsigned int code_len = code_bytes;
+		unsigned char c;
+		u8 *ip;
+
+		printk("\n" KERN_EMERG "Stack: ");
+		show_stack_log_lvl(NULL, regs, &regs->sp, 0, KERN_EMERG);
+
+		printk(KERN_EMERG "Code: ");
+
+		ip = (u8 *)regs->ip - code_prologue;
+		if (ip < (u8 *)PAGE_OFFSET || probe_kernel_address(ip, c)) {
+			/* try starting at EIP */
+			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 EIP 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 (ip < PAGE_OFFSET)
+		return 0;
+	if (probe_kernel_address((unsigned short *)ip, 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)
+{
+	unsigned long flags;
+
+	oops_enter();
+
+	if (die_owner != raw_smp_processor_id()) {
+		console_verbose();
+		raw_local_irq_save(flags);
+		__raw_spin_lock(&die_lock);
+		die_owner = smp_processor_id();
+		die_nest_count = 0;
+		bust_spinlocks(1);
+	} else {
+		raw_local_irq_save(flags);
+	}
+	die_nest_count++;
+	return flags;
+}
+
+void __kprobes oops_end(unsigned long flags, struct pt_regs *regs, int signr)
+{
+	bust_spinlocks(0);
+	die_owner = -1;
+	add_taint(TAINT_DIE);
+	__raw_spin_unlock(&die_lock);
+	raw_local_irq_restore(flags);
+
+	if (!regs)
+		return;
+
+	if (kexec_should_crash(current))
+		crash_kexec(regs);
+
+	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)
+{
+	unsigned short ss;
+	unsigned long sp;
+
+	printk(KERN_EMERG "%s: %04lx [#%d] ", 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);
+	/* Executive summary in case the oops scrolled away */
+	sp = (unsigned long) (&regs->sp);
+	savesegment(ss, ss);
+	if (user_mode(regs)) {
+		sp = regs->sp;
+		ss = regs->ss & 0xffff;
+	}
+	printk(KERN_EMERG "EIP: [<%08lx>] ", regs->ip);
+	print_symbol("%s", regs->ip);
+	printk(" SS:ESP %04x:%08lx\n", ss, sp);
+	return 0;
+}
+
+/*
+ * This is gone through when something in the kernel has done something bad
+ * and is about to be terminated:
+ */
+void die(const char *str, struct pt_regs *regs, long err)
+{
+	unsigned long flags = oops_begin();
+
+	if (die_nest_count < 3) {
+		report_bug(regs->ip, regs);
+
+		if (__die(str, regs, err))
+			regs = NULL;
+	} else {
+		printk(KERN_EMERG "Recursive die() failure, output suppressed\n");
+	}
+
+	oops_end(flags, regs, SIGSEGV);
+}
+
+static int __init kstack_setup(char *s)
+{
+	kstack_depth_to_print = simple_strtoul(s, NULL, 0);
+
+	return 1;
+}
+__setup("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);