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qubes-linux-kernel/patches.suse/stack-unwind

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2010-07-07 11:12:45 +00:00
Subject: DWARF2 EH-frame based stack unwinding
From: jbeulich@novell.com
Patch-mainline: no
This includes reverting f1883f86dea84fe47a71a39fc1afccc005915ed8.
Update Jan 17 2009 jeffm:
- Something in 2.6.29-rc1 tweaked the frame pointer code somehow, so I fixed
that up.
---
Makefile | 5
arch/x86/Kconfig | 2
arch/x86/Makefile | 2
arch/x86/include/asm/system.h | 10
arch/x86/include/asm/unwind.h | 163 ++++
arch/x86/kernel/dumpstack.c | 89 ++
arch/x86/kernel/dumpstack.h | 4
arch/x86/kernel/dumpstack_32.c | 18
arch/x86/kernel/dumpstack_64.c | 20
arch/x86/kernel/entry_32.S | 35 +
arch/x86/kernel/entry_64.S | 34
include/asm-generic/vmlinux.lds.h | 22
include/linux/module.h | 3
include/linux/unwind.h | 135 +++
init/main.c | 3
kernel/Makefile | 1
kernel/module.c | 15
kernel/unwind.c | 1303 ++++++++++++++++++++++++++++++++++++++
lib/Kconfig.debug | 18
19 files changed, 1866 insertions(+), 16 deletions(-)
--- a/Makefile
+++ b/Makefile
@@ -570,6 +570,11 @@ else
KBUILD_CFLAGS += -fomit-frame-pointer
endif
+ifdef CONFIG_UNWIND_INFO
+KBUILD_CFLAGS += -fasynchronous-unwind-tables
+LDFLAGS_vmlinux += --eh-frame-hdr
+endif
+
ifdef CONFIG_DEBUG_INFO
KBUILD_CFLAGS += -g
KBUILD_AFLAGS += -gdwarf-2
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -487,7 +487,7 @@ config X86_ES7000
config SCHED_OMIT_FRAME_POINTER
def_bool y
prompt "Single-depth WCHAN output"
- depends on X86
+ depends on X86 && !STACK_UNWIND
---help---
Calculate simpler /proc/<PID>/wchan values. If this option
is disabled then wchan values will recurse back to the
--- a/arch/x86/Makefile
+++ b/arch/x86/Makefile
@@ -105,7 +105,9 @@ KBUILD_CFLAGS += -pipe
# Workaround for a gcc prelease that unfortunately was shipped in a suse release
KBUILD_CFLAGS += -Wno-sign-compare
#
+ifneq ($(CONFIG_UNWIND_INFO),y)
KBUILD_CFLAGS += -fno-asynchronous-unwind-tables
+endif
# prevent gcc from generating any FP code by mistake
KBUILD_CFLAGS += $(call cc-option,-mno-sse -mno-mmx -mno-sse2 -mno-3dnow,)
--- a/arch/x86/include/asm/system.h
+++ b/arch/x86/include/asm/system.h
@@ -123,12 +123,22 @@ do { \
#define __switch_canary_iparam
#endif /* CC_STACKPROTECTOR */
+/* The stack unwind code needs this but it pollutes traces otherwise */
+#ifdef CONFIG_UNWIND_INFO
+#define THREAD_RETURN_SYM \
+ ".globl thread_return\n" \
+ "thread_return:\n\t"
+#else
+#define THREAD_RETURN_SYM
+#endif
+
/* Save restore flags to clear handle leaking NT */
#define switch_to(prev, next, last) \
asm volatile(SAVE_CONTEXT \
"movq %%rsp,%P[threadrsp](%[prev])\n\t" /* save RSP */ \
"movq %P[threadrsp](%[next]),%%rsp\n\t" /* restore RSP */ \
"call __switch_to\n\t" \
+ THREAD_RETURN_SYM \
"movq "__percpu_arg([current_task])",%%rsi\n\t" \
__switch_canary \
"movq %P[thread_info](%%rsi),%%r8\n\t" \
--- /dev/null
+++ b/arch/x86/include/asm/unwind.h
@@ -0,0 +1,163 @@
+#ifndef _ASM_X86_UNWIND_H
+#define _ASM_X86_UNWIND_H
+
+/*
+ * Copyright (C) 2002-2009 Novell, Inc.
+ * Jan Beulich <jbeulich@novell.com>
+ * This code is released under version 2 of the GNU GPL.
+ */
+
+#ifdef CONFIG_STACK_UNWIND
+
+#include <linux/sched.h>
+#include <linux/uaccess.h>
+#include <asm/ptrace.h>
+
+struct unwind_frame_info
+{
+ struct pt_regs regs;
+ struct task_struct *task;
+ unsigned call_frame:1;
+};
+
+#define UNW_PC(frame) (frame)->regs.ip
+#define UNW_SP(frame) (frame)->regs.sp
+#ifdef CONFIG_FRAME_POINTER
+#define UNW_FP(frame) (frame)->regs.bp
+#define FRAME_LINK_OFFSET 0
+#define STACK_BOTTOM(tsk) STACK_LIMIT((tsk)->thread.sp0)
+#define TSK_STACK_TOP(tsk) ((tsk)->thread.sp0)
+#else
+#define UNW_FP(frame) ((void)(frame), 0UL)
+#endif
+/* On x86-64, might need to account for the special exception and interrupt
+ handling stacks here, since normally
+ EXCEPTION_STACK_ORDER < THREAD_ORDER < IRQSTACK_ORDER,
+ but the construct is needed only for getting across the stack switch to
+ the interrupt stack - thus considering the IRQ stack itself is unnecessary,
+ and the overhead of comparing against all exception handling stacks seems
+ not desirable. */
+#define STACK_LIMIT(ptr) (((ptr) - 1) & ~(THREAD_SIZE - 1))
+
+#ifdef CONFIG_X86_64
+
+#include <asm/vsyscall.h>
+
+#define FRAME_RETADDR_OFFSET 8
+
+#define UNW_REGISTER_INFO \
+ PTREGS_INFO(ax), \
+ PTREGS_INFO(dx), \
+ PTREGS_INFO(cx), \
+ PTREGS_INFO(bx), \
+ PTREGS_INFO(si), \
+ PTREGS_INFO(di), \
+ PTREGS_INFO(bp), \
+ PTREGS_INFO(sp), \
+ PTREGS_INFO(r8), \
+ PTREGS_INFO(r9), \
+ PTREGS_INFO(r10), \
+ PTREGS_INFO(r11), \
+ PTREGS_INFO(r12), \
+ PTREGS_INFO(r13), \
+ PTREGS_INFO(r14), \
+ PTREGS_INFO(r15), \
+ PTREGS_INFO(ip)
+
+#else /* X86_32 */
+
+#include <asm/fixmap.h>
+
+#define FRAME_RETADDR_OFFSET 4
+
+#define UNW_REGISTER_INFO \
+ PTREGS_INFO(ax), \
+ PTREGS_INFO(cx), \
+ PTREGS_INFO(dx), \
+ PTREGS_INFO(bx), \
+ PTREGS_INFO(sp), \
+ PTREGS_INFO(bp), \
+ PTREGS_INFO(si), \
+ PTREGS_INFO(di), \
+ PTREGS_INFO(ip)
+
+#endif
+
+#define UNW_DEFAULT_RA(raItem, dataAlign) \
+ ((raItem).where == Memory && \
+ !((raItem).value * (dataAlign) + sizeof(void *)))
+
+static inline void arch_unw_init_frame_info(struct unwind_frame_info *info,
+ /*const*/ struct pt_regs *regs)
+{
+#ifdef CONFIG_X86_64
+ info->regs = *regs;
+#else
+ if (user_mode_vm(regs))
+ info->regs = *regs;
+ else {
+ memcpy(&info->regs, regs, offsetof(struct pt_regs, sp));
+ info->regs.sp = (unsigned long)&regs->sp;
+ info->regs.ss = __KERNEL_DS;
+ }
+#endif
+}
+
+static inline void arch_unw_init_blocked(struct unwind_frame_info *info)
+{
+#ifdef CONFIG_X86_64
+ extern const char thread_return[];
+
+ memset(&info->regs, 0, sizeof(info->regs));
+ info->regs.ip = (unsigned long)thread_return;
+ info->regs.cs = __KERNEL_CS;
+ probe_kernel_address(info->task->thread.sp, info->regs.bp);
+ info->regs.sp = info->task->thread.sp;
+ info->regs.ss = __KERNEL_DS;
+#else
+ memset(&info->regs, 0, sizeof(info->regs));
+ info->regs.ip = info->task->thread.ip;
+ info->regs.cs = __KERNEL_CS;
+ probe_kernel_address(info->task->thread.sp, info->regs.bp);
+ info->regs.sp = info->task->thread.sp;
+ info->regs.ss = __KERNEL_DS;
+ info->regs.ds = __USER_DS;
+ info->regs.es = __USER_DS;
+#endif
+}
+
+extern asmlinkage int
+arch_unwind_init_running(struct unwind_frame_info *,
+ unwind_callback_fn,
+ const struct stacktrace_ops *, void *data);
+
+static inline int arch_unw_user_mode(/*const*/ struct unwind_frame_info *info)
+{
+#ifdef CONFIG_X86_64
+ return user_mode(&info->regs)
+ || (long)info->regs.ip >= 0
+ || (info->regs.ip >= VSYSCALL_START && info->regs.ip < VSYSCALL_END)
+ || (long)info->regs.sp >= 0;
+#else
+ return user_mode_vm(&info->regs)
+ || info->regs.ip < PAGE_OFFSET
+ || (info->regs.ip >= __fix_to_virt(FIX_VDSO)
+ && info->regs.ip < __fix_to_virt(FIX_VDSO) + PAGE_SIZE)
+ || info->regs.sp < PAGE_OFFSET;
+#endif
+}
+
+#else
+
+#define UNW_PC(frame) ((void)(frame), 0UL)
+#define UNW_SP(frame) ((void)(frame), 0UL)
+#define UNW_FP(frame) ((void)(frame), 0UL)
+
+static inline int arch_unw_user_mode(const void *info)
+{
+ return 0;
+}
+
+#endif
+
+#endif /* _ASM_X86_UNWIND_H */
--- a/arch/x86/kernel/dumpstack.c
+++ b/arch/x86/kernel/dumpstack.c
@@ -20,6 +20,7 @@
#endif
#include <asm/stacktrace.h>
+#include <linux/unwind.h>
#include "dumpstack.h"
@@ -27,6 +28,11 @@ int panic_on_unrecovered_nmi;
int panic_on_io_nmi;
unsigned int code_bytes = 64;
int kstack_depth_to_print = 3 * STACKSLOTS_PER_LINE;
+#ifdef CONFIG_STACK_UNWIND
+static int call_trace = 1;
+#else
+#define call_trace (-1)
+#endif
static int die_counter;
void printk_address(unsigned long address, int reliable)
@@ -66,6 +72,71 @@ print_ftrace_graph_addr(unsigned long ad
{ }
#endif
+int asmlinkage dump_trace_unwind(struct unwind_frame_info *info,
+ const struct stacktrace_ops *ops, void *data)
+{
+ int n = 0;
+#ifdef CONFIG_UNWIND_INFO
+ unsigned long sp = UNW_SP(info);
+
+ if (arch_unw_user_mode(info))
+ return -1;
+ while (unwind(info) == 0 && UNW_PC(info)) {
+ n++;
+ ops->address(data, UNW_PC(info), 1);
+ if (arch_unw_user_mode(info))
+ break;
+ if ((sp & ~(PAGE_SIZE - 1)) == (UNW_SP(info) & ~(PAGE_SIZE - 1))
+ && sp > UNW_SP(info))
+ break;
+ sp = UNW_SP(info);
+ }
+#endif
+ return n;
+}
+
+int try_stack_unwind(struct task_struct *task, struct pt_regs *regs,
+ unsigned long **stack, unsigned long *bp,
+ const struct stacktrace_ops *ops, void *data)
+{
+#ifdef CONFIG_UNWIND_INFO
+ int unw_ret = 0;
+ struct unwind_frame_info info;
+ if (call_trace < 0)
+ return 0;
+
+ if (regs) {
+ if (unwind_init_frame_info(&info, task, regs) == 0)
+ unw_ret = dump_trace_unwind(&info, ops, data);
+ } else if (task == current)
+ unw_ret = unwind_init_running(&info, dump_trace_unwind, ops, data);
+ else {
+ if (unwind_init_blocked(&info, task) == 0)
+ unw_ret = dump_trace_unwind(&info, ops, data);
+ }
+ if (unw_ret > 0) {
+ if (call_trace == 1 && !arch_unw_user_mode(&info)) {
+ ops->warning_symbol(data, "DWARF2 unwinder stuck at %s\n",
+ UNW_PC(&info));
+ if ((long)UNW_SP(&info) < 0) {
+ ops->warning(data, "Leftover inexact backtrace:\n");
+ *stack = (unsigned long *)UNW_SP(&info);
+ if (!stack) {
+ *bp = UNW_FP(&info);
+ return -1;
+ }
+ } else
+ ops->warning(data, "Full inexact backtrace again:\n");
+ } else if (call_trace >= 1) {
+ return -1;
+ } else
+ ops->warning(data, "Full inexact backtrace again:\n");
+ } else
+ ops->warning(data, "Inexact backtrace:\n");
+#endif
+ return 0;
+}
+
/*
* x86-64 can have up to three kernel stacks:
* process stack
@@ -396,3 +467,21 @@ static int __init code_bytes_setup(char
return 1;
}
__setup("code_bytes=", code_bytes_setup);
+
+#ifdef CONFIG_STACK_UNWIND
+static int __init call_trace_setup(char *s)
+{
+ if (!s)
+ return -EINVAL;
+ if (strcmp(s, "old") == 0)
+ call_trace = -1;
+ else if (strcmp(s, "both") == 0)
+ call_trace = 0;
+ else if (strcmp(s, "newfallback") == 0)
+ call_trace = 1;
+ else if (strcmp(s, "new") == 0)
+ call_trace = 2;
+ return 0;
+}
+early_param("call_trace", call_trace_setup);
+#endif
--- a/arch/x86/kernel/dumpstack.h
+++ b/arch/x86/kernel/dumpstack.h
@@ -22,6 +22,10 @@ extern void
show_stack_log_lvl(struct task_struct *task, struct pt_regs *regs,
unsigned long *sp, unsigned long bp, char *log_lvl);
+int try_stack_unwind(struct task_struct *task, struct pt_regs *regs,
+ unsigned long **stack, unsigned long *bp,
+ const struct stacktrace_ops *ops, void *data);
+
extern unsigned int code_bytes;
/* The form of the top of the frame on the stack */
--- a/arch/x86/kernel/dumpstack_32.c
+++ b/arch/x86/kernel/dumpstack_32.c
@@ -28,14 +28,6 @@ void dump_trace(struct task_struct *task
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) {
@@ -48,6 +40,16 @@ void dump_trace(struct task_struct *task
}
#endif
+ if (try_stack_unwind(task, regs, &stack, &bp, ops, data))
+ return;
+
+ if (!stack) {
+ unsigned long dummy;
+ stack = &dummy;
+ if (task && task != current)
+ stack = (unsigned long *)task->thread.sp;
+ }
+
for (;;) {
struct thread_info *context;
--- a/arch/x86/kernel/dumpstack_64.c
+++ b/arch/x86/kernel/dumpstack_64.c
@@ -14,6 +14,7 @@
#include <linux/bug.h>
#include <linux/nmi.h>
+#include <linux/unwind.h>
#include <asm/stacktrace.h>
#include "dumpstack.h"
@@ -154,13 +155,6 @@ void dump_trace(struct task_struct *task
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) {
@@ -173,6 +167,18 @@ void dump_trace(struct task_struct *task
}
#endif
+ if (try_stack_unwind(task, regs, &stack, &bp, ops, data)) {
+ put_cpu();
+ return;
+ }
+
+ if (!stack) {
+ unsigned long dummy;
+ stack = &dummy;
+ if (task && task != current)
+ stack = (unsigned long *)task->thread.sp;
+ }
+
/*
* Print function call entries in all stacks, starting at the
* current stack address. If the stacks consist of nested
--- a/arch/x86/kernel/entry_32.S
+++ b/arch/x86/kernel/entry_32.S
@@ -1064,6 +1064,41 @@ END(spurious_interrupt_bug)
*/
.popsection
+#ifdef CONFIG_STACK_UNWIND
+ENTRY(arch_unwind_init_running)
+ CFI_STARTPROC
+ movl 4(%esp), %edx
+ movl (%esp), %ecx
+ leal 4(%esp), %eax
+ movl %ebx, PT_EBX(%edx)
+ xorl %ebx, %ebx
+ movl %ebx, PT_ECX(%edx)
+ movl %ebx, PT_EDX(%edx)
+ movl %esi, PT_ESI(%edx)
+ movl %edi, PT_EDI(%edx)
+ movl %ebp, PT_EBP(%edx)
+ movl %ebx, PT_EAX(%edx)
+ movl $__USER_DS, PT_DS(%edx)
+ movl $__USER_DS, PT_ES(%edx)
+ movl $__KERNEL_PERCPU, PT_FS(%edx)
+ movl $__KERNEL_STACK_CANARY, PT_GS(%edx)
+ movl %eax, PT_OLDESP(%edx)
+ movl 16(%esp), %eax
+ movl %ebx, PT_ORIG_EAX(%edx)
+ movl %ecx, PT_EIP(%edx)
+ movl 12(%esp), %ecx
+ movl $__KERNEL_CS, PT_CS(%edx)
+ movl %eax, 12(%esp)
+ movl 8(%esp), %eax
+ movl %ecx, 8(%esp)
+ movl %ebx, PT_EFLAGS(%edx)
+ movl PT_EBX(%edx), %ebx
+ movl $__KERNEL_DS, PT_OLDSS(%edx)
+ jmpl *%eax
+ CFI_ENDPROC
+ENDPROC(arch_unwind_init_running)
+#endif
+
ENTRY(kernel_thread_helper)
pushl $0 # fake return address for unwinder
CFI_STARTPROC
--- a/arch/x86/kernel/entry_64.S
+++ b/arch/x86/kernel/entry_64.S
@@ -1232,6 +1232,40 @@ ENTRY(call_softirq)
CFI_ENDPROC
END(call_softirq)
+#ifdef CONFIG_STACK_UNWIND
+ENTRY(arch_unwind_init_running)
+ CFI_STARTPROC
+ movq %r15, R15(%rdi)
+ movq %r14, R14(%rdi)
+ xchgq %rsi, %rdx
+ movq %r13, R13(%rdi)
+ movq %r12, R12(%rdi)
+ xorl %eax, %eax
+ movq %rbp, RBP(%rdi)
+ movq %rbx, RBX(%rdi)
+ movq (%rsp), %r9
+ xchgq %rdx, %rcx
+ movq %rax, R11(%rdi)
+ movq %rax, R10(%rdi)
+ movq %rax, R9(%rdi)
+ movq %rax, R8(%rdi)
+ movq %rax, RAX(%rdi)
+ movq %rax, RCX(%rdi)
+ movq %rax, RDX(%rdi)
+ movq %rax, RSI(%rdi)
+ movq %rax, RDI(%rdi)
+ movq %rax, ORIG_RAX(%rdi)
+ movq %r9, RIP(%rdi)
+ leaq 8(%rsp), %r9
+ movq $__KERNEL_CS, CS(%rdi)
+ movq %rax, EFLAGS(%rdi)
+ movq %r9, RSP(%rdi)
+ movq $__KERNEL_DS, SS(%rdi)
+ jmpq *%rcx
+ CFI_ENDPROC
+END(arch_unwind_init_running)
+#endif
+
#ifdef CONFIG_XEN
zeroentry xen_hypervisor_callback xen_do_hypervisor_callback
--- a/include/asm-generic/vmlinux.lds.h
+++ b/include/asm-generic/vmlinux.lds.h
@@ -341,6 +341,8 @@
MEM_KEEP(exit.rodata) \
} \
\
+ EH_FRAME \
+ \
/* Built-in module parameters. */ \
__param : AT(ADDR(__param) - LOAD_OFFSET) { \
VMLINUX_SYMBOL(__start___param) = .; \
@@ -758,3 +760,23 @@
BSS(bss_align) \
. = ALIGN(stop_align); \
VMLINUX_SYMBOL(__bss_stop) = .;
+
+#ifdef CONFIG_STACK_UNWIND
+#define EH_FRAME \
+ /* Unwind data binary search table */ \
+ . = ALIGN(8); \
+ .eh_frame_hdr : AT(ADDR(.eh_frame_hdr) - LOAD_OFFSET) { \
+ VMLINUX_SYMBOL(__start_unwind_hdr) = .; \
+ *(.eh_frame_hdr) \
+ VMLINUX_SYMBOL(__end_unwind_hdr) = .; \
+ } \
+ /* Unwind data */ \
+ . = ALIGN(8); \
+ .eh_frame : AT(ADDR(.eh_frame) - LOAD_OFFSET) { \
+ VMLINUX_SYMBOL(__start_unwind) = .; \
+ *(.eh_frame) \
+ VMLINUX_SYMBOL(__end_unwind) = .; \
+ }
+#else
+#define EH_FRAME
+#endif
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -301,6 +301,9 @@ struct module
/* The size of the executable code in each section. */
unsigned int init_text_size, core_text_size;
+ /* The handle returned from unwind_add_table. */
+ void *unwind_info;
+
/* Arch-specific module values */
struct mod_arch_specific arch;
--- /dev/null
+++ b/include/linux/unwind.h
@@ -0,0 +1,135 @@
+#ifndef _LINUX_UNWIND_H
+#define _LINUX_UNWIND_H
+
+/*
+ * Copyright (C) 2002-2009 Novell, Inc.
+ * Jan Beulich <jbeulich@novell.com>
+ * This code is released under version 2 of the GNU GPL.
+ *
+ * A simple API for unwinding kernel stacks. This is used for
+ * debugging and error reporting purposes. The kernel doesn't need
+ * full-blown stack unwinding with all the bells and whistles, so there
+ * is not much point in implementing the full Dwarf2 unwind API.
+ */
+
+#include <linux/linkage.h>
+
+struct module;
+struct stacktrace_ops;
+struct unwind_frame_info;
+
+typedef asmlinkage int (*unwind_callback_fn)(struct unwind_frame_info *,
+ const struct stacktrace_ops *,
+ void *);
+
+#ifdef CONFIG_STACK_UNWIND
+
+#include <asm/unwind.h>
+#include <asm/stacktrace.h>
+
+#ifndef ARCH_UNWIND_SECTION_NAME
+#define ARCH_UNWIND_SECTION_NAME ".eh_frame"
+#endif
+
+/*
+ * Initialize unwind support.
+ */
+extern void unwind_init(void);
+extern void unwind_setup(void);
+
+#ifdef CONFIG_MODULES
+
+extern void *unwind_add_table(struct module *,
+ const void *table_start,
+ unsigned long table_size);
+
+extern void unwind_remove_table(void *handle, int init_only);
+
+#endif
+
+extern int unwind_init_frame_info(struct unwind_frame_info *,
+ struct task_struct *,
+ /*const*/ struct pt_regs *);
+
+/*
+ * Prepare to unwind a blocked task.
+ */
+extern int unwind_init_blocked(struct unwind_frame_info *,
+ struct task_struct *);
+
+/*
+ * Prepare to unwind the currently running thread.
+ */
+extern int unwind_init_running(struct unwind_frame_info *,
+ unwind_callback_fn,
+ const struct stacktrace_ops *,
+ void *data);
+
+/*
+ * Unwind to previous to frame. Returns 0 if successful, negative
+ * number in case of an error.
+ */
+extern int unwind(struct unwind_frame_info *);
+
+/*
+ * Unwind until the return pointer is in user-land (or until an error
+ * occurs). Returns 0 if successful, negative number in case of
+ * error.
+ */
+extern int unwind_to_user(struct unwind_frame_info *);
+
+#else /* CONFIG_STACK_UNWIND */
+
+struct unwind_frame_info {};
+
+static inline void unwind_init(void) {}
+static inline void unwind_setup(void) {}
+
+#ifdef CONFIG_MODULES
+
+static inline void *unwind_add_table(struct module *mod,
+ const void *table_start,
+ unsigned long table_size)
+{
+ return NULL;
+}
+
+#endif
+
+static inline void unwind_remove_table(void *handle, int init_only)
+{
+}
+
+static inline int unwind_init_frame_info(struct unwind_frame_info *info,
+ struct task_struct *tsk,
+ const struct pt_regs *regs)
+{
+ return -ENOSYS;
+}
+
+static inline int unwind_init_blocked(struct unwind_frame_info *info,
+ struct task_struct *tsk)
+{
+ return -ENOSYS;
+}
+
+static inline int unwind_init_running(struct unwind_frame_info *info,
+ unwind_callback_fn cb,
+ const struct stacktrace_ops *ops,
+ void *data)
+{
+ return -ENOSYS;
+}
+
+static inline int unwind(struct unwind_frame_info *info)
+{
+ return -ENOSYS;
+}
+
+static inline int unwind_to_user(struct unwind_frame_info *info)
+{
+ return -ENOSYS;
+}
+
+#endif /* CONFIG_STACK_UNWIND */
+#endif /* _LINUX_UNWIND_H */
--- a/init/main.c
+++ b/init/main.c
@@ -50,6 +50,7 @@
#include <linux/rmap.h>
#include <linux/mempolicy.h>
#include <linux/key.h>
+#include <linux/unwind.h>
#include <linux/buffer_head.h>
#include <linux/page_cgroup.h>
#include <linux/debug_locks.h>
@@ -560,6 +561,7 @@ asmlinkage void __init start_kernel(void
* Need to run as early as possible, to initialize the
* lockdep hash:
*/
+ unwind_init();
lockdep_init();
debug_objects_early_init();
@@ -586,6 +588,7 @@ asmlinkage void __init start_kernel(void
setup_arch(&command_line);
mm_init_owner(&init_mm, &init_task);
setup_command_line(command_line);
+ unwind_setup();
setup_nr_cpu_ids();
setup_per_cpu_areas();
smp_prepare_boot_cpu(); /* arch-specific boot-cpu hooks */
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -53,6 +53,7 @@ obj-$(CONFIG_PROVE_LOCKING) += spinlock.
obj-$(CONFIG_UID16) += uid16.o
obj-$(CONFIG_MODULES) += module.o
obj-$(CONFIG_KALLSYMS) += kallsyms.o
+obj-$(CONFIG_STACK_UNWIND) += unwind.o
obj-$(CONFIG_PM) += power/
obj-$(CONFIG_FREEZER) += power/
obj-$(CONFIG_BSD_PROCESS_ACCT) += acct.o
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -44,6 +44,7 @@
#include <linux/device.h>
#include <linux/string.h>
#include <linux/mutex.h>
+#include <linux/unwind.h>
#include <linux/rculist.h>
#include <asm/uaccess.h>
#include <asm/cacheflush.h>
@@ -1501,6 +1502,8 @@ static void free_module(struct module *m
remove_sect_attrs(mod);
mod_kobject_remove(mod);
+ unwind_remove_table(mod->unwind_info, 0);
+
/* Arch-specific cleanup. */
module_arch_cleanup(mod);
@@ -2064,6 +2067,7 @@ static noinline struct module *load_modu
unsigned int symindex = 0;
unsigned int strindex = 0;
unsigned int modindex, versindex, infoindex, pcpuindex;
+ unsigned int unwindex = 0;
struct module *mod;
long err = 0;
void *ptr = NULL; /* Stops spurious gcc warning */
@@ -2146,10 +2150,15 @@ static noinline struct module *load_modu
versindex = find_sec(hdr, sechdrs, secstrings, "__versions");
infoindex = find_sec(hdr, sechdrs, secstrings, ".modinfo");
pcpuindex = find_pcpusec(hdr, sechdrs, secstrings);
+#ifdef ARCH_UNWIND_SECTION_NAME
+ unwindex = find_sec(hdr, sechdrs, secstrings, ARCH_UNWIND_SECTION_NAME);
+#endif
/* Don't keep modinfo and version sections. */
sechdrs[infoindex].sh_flags &= ~(unsigned long)SHF_ALLOC;
sechdrs[versindex].sh_flags &= ~(unsigned long)SHF_ALLOC;
+ if (unwindex)
+ sechdrs[unwindex].sh_flags |= SHF_ALLOC;
/* Check module struct version now, before we try to use module. */
if (!check_modstruct_version(sechdrs, versindex, mod)) {
@@ -2511,6 +2520,11 @@ static noinline struct module *load_modu
}
#endif
+ /* Size of section 0 is 0, so this works well if no unwind info. */
+ mod->unwind_info = unwind_add_table(mod,
+ (void *)sechdrs[unwindex].sh_addr,
+ sechdrs[unwindex].sh_size);
+
/* Get rid of temporary copy */
vfree(hdr);
@@ -2632,6 +2646,7 @@ SYSCALL_DEFINE3(init_module, void __user
/* Drop initial reference. */
module_put(mod);
trim_init_extable(mod);
+ unwind_remove_table(mod->unwind_info, 1);
#ifdef CONFIG_KALLSYMS
mod->num_symtab = mod->core_num_syms;
mod->symtab = mod->core_symtab;
--- /dev/null
+++ b/kernel/unwind.c
@@ -0,0 +1,1303 @@
+/*
+ * Copyright (C) 2002-2006 Novell, Inc.
+ * Jan Beulich <jbeulich@novell.com>
+ * This code is released under version 2 of the GNU GPL.
+ *
+ * A simple API for unwinding kernel stacks. This is used for
+ * debugging and error reporting purposes. The kernel doesn't need
+ * full-blown stack unwinding with all the bells and whistles, so there
+ * is not much point in implementing the full Dwarf2 unwind API.
+ */
+
+#include <linux/unwind.h>
+#include <linux/module.h>
+#include <linux/bootmem.h>
+#include <linux/sort.h>
+#include <linux/stop_machine.h>
+#include <linux/uaccess.h>
+#include <asm/sections.h>
+#include <asm/unaligned.h>
+#include <linux/slab.h>
+
+extern const char __start_unwind[], __end_unwind[];
+extern const u8 __start_unwind_hdr[], __end_unwind_hdr[];
+
+#define MAX_STACK_DEPTH 8
+
+#define EXTRA_INFO(f) { \
+ BUILD_BUG_ON_ZERO(offsetof(struct unwind_frame_info, f) \
+ % FIELD_SIZEOF(struct unwind_frame_info, f)) \
+ + offsetof(struct unwind_frame_info, f) \
+ / FIELD_SIZEOF(struct unwind_frame_info, f), \
+ FIELD_SIZEOF(struct unwind_frame_info, f) \
+ }
+#define PTREGS_INFO(f) EXTRA_INFO(regs.f)
+
+static const struct {
+ unsigned offs:BITS_PER_LONG / 2;
+ unsigned width:BITS_PER_LONG / 2;
+} reg_info[] = {
+ UNW_REGISTER_INFO
+};
+
+#undef PTREGS_INFO
+#undef EXTRA_INFO
+
+#ifndef REG_INVALID
+#define REG_INVALID(r) (reg_info[r].width == 0)
+#endif
+
+#define DW_CFA_nop 0x00
+#define DW_CFA_set_loc 0x01
+#define DW_CFA_advance_loc1 0x02
+#define DW_CFA_advance_loc2 0x03
+#define DW_CFA_advance_loc4 0x04
+#define DW_CFA_offset_extended 0x05
+#define DW_CFA_restore_extended 0x06
+#define DW_CFA_undefined 0x07
+#define DW_CFA_same_value 0x08
+#define DW_CFA_register 0x09
+#define DW_CFA_remember_state 0x0a
+#define DW_CFA_restore_state 0x0b
+#define DW_CFA_def_cfa 0x0c
+#define DW_CFA_def_cfa_register 0x0d
+#define DW_CFA_def_cfa_offset 0x0e
+#define DW_CFA_def_cfa_expression 0x0f
+#define DW_CFA_expression 0x10
+#define DW_CFA_offset_extended_sf 0x11
+#define DW_CFA_def_cfa_sf 0x12
+#define DW_CFA_def_cfa_offset_sf 0x13
+#define DW_CFA_val_offset 0x14
+#define DW_CFA_val_offset_sf 0x15
+#define DW_CFA_val_expression 0x16
+#define DW_CFA_lo_user 0x1c
+#define DW_CFA_GNU_window_save 0x2d
+#define DW_CFA_GNU_args_size 0x2e
+#define DW_CFA_GNU_negative_offset_extended 0x2f
+#define DW_CFA_hi_user 0x3f
+
+#define DW_EH_PE_FORM 0x07
+#define DW_EH_PE_native 0x00
+#define DW_EH_PE_leb128 0x01
+#define DW_EH_PE_data2 0x02
+#define DW_EH_PE_data4 0x03
+#define DW_EH_PE_data8 0x04
+#define DW_EH_PE_signed 0x08
+#define DW_EH_PE_ADJUST 0x70
+#define DW_EH_PE_abs 0x00
+#define DW_EH_PE_pcrel 0x10
+#define DW_EH_PE_textrel 0x20
+#define DW_EH_PE_datarel 0x30
+#define DW_EH_PE_funcrel 0x40
+#define DW_EH_PE_aligned 0x50
+#define DW_EH_PE_indirect 0x80
+#define DW_EH_PE_omit 0xff
+
+typedef unsigned long uleb128_t;
+typedef signed long sleb128_t;
+#define sleb128abs __builtin_labs
+
+static struct unwind_table {
+ struct {
+ unsigned long pc;
+ unsigned long range;
+ } core, init;
+ const void *address;
+ unsigned long size;
+ const unsigned char *header;
+ unsigned long hdrsz;
+ struct unwind_table *link;
+ const char *name;
+} root_table;
+
+struct unwind_item {
+ enum item_location {
+ Nowhere,
+ Memory,
+ Register,
+ Value
+ } where;
+ uleb128_t value;
+};
+
+struct unwind_state {
+ uleb128_t loc, org;
+ const u8 *cieStart, *cieEnd;
+ uleb128_t codeAlign;
+ sleb128_t dataAlign;
+ struct cfa {
+ uleb128_t reg, offs;
+ } cfa;
+ struct unwind_item regs[ARRAY_SIZE(reg_info)];
+ unsigned stackDepth:8;
+ unsigned version:8;
+ const u8 *label;
+ const u8 *stack[MAX_STACK_DEPTH];
+};
+
+static const struct cfa badCFA = { ARRAY_SIZE(reg_info), 1 };
+
+static unsigned unwind_debug;
+static int __init unwind_debug_setup(char *s)
+{
+ unwind_debug = simple_strtoul(s, NULL, 0);
+ return 1;
+}
+__setup("unwind_debug=", unwind_debug_setup);
+#define dprintk(lvl, fmt, args...) \
+ ((void)(lvl > unwind_debug \
+ || printk(KERN_DEBUG "unwind: " fmt "\n", ##args)))
+
+static struct unwind_table *find_table(unsigned long pc)
+{
+ struct unwind_table *table;
+
+ for (table = &root_table; table; table = table->link)
+ if ((pc >= table->core.pc
+ && pc < table->core.pc + table->core.range)
+ || (pc >= table->init.pc
+ && pc < table->init.pc + table->init.range))
+ break;
+
+ return table;
+}
+
+static unsigned long read_pointer(const u8 **pLoc,
+ const void *end,
+ signed ptrType,
+ unsigned long text_base,
+ unsigned long data_base);
+
+static void init_unwind_table(struct unwind_table *table,
+ const char *name,
+ const void *core_start,
+ unsigned long core_size,
+ const void *init_start,
+ unsigned long init_size,
+ const void *table_start,
+ unsigned long table_size,
+ const u8 *header_start,
+ unsigned long header_size)
+{
+ const u8 *ptr = header_start + 4;
+ const u8 *end = header_start + header_size;
+
+ table->core.pc = (unsigned long)core_start;
+ table->core.range = core_size;
+ table->init.pc = (unsigned long)init_start;
+ table->init.range = init_size;
+ table->address = table_start;
+ table->size = table_size;
+ /* See if the linker provided table looks valid. */
+ if (header_size <= 4
+ || header_start[0] != 1
+ || (void *)read_pointer(&ptr, end, header_start[1], 0, 0)
+ != table_start
+ || !read_pointer(&ptr, end, header_start[2], 0, 0)
+ || !read_pointer(&ptr, end, header_start[3], 0,
+ (unsigned long)header_start)
+ || !read_pointer(&ptr, end, header_start[3], 0,
+ (unsigned long)header_start))
+ header_start = NULL;
+ table->hdrsz = header_size;
+ smp_wmb();
+ table->header = header_start;
+ table->link = NULL;
+ table->name = name;
+}
+
+void __init unwind_init(void)
+{
+ init_unwind_table(&root_table, "kernel",
+ _text, _end - _text,
+ NULL, 0,
+ __start_unwind, __end_unwind - __start_unwind,
+ __start_unwind_hdr, __end_unwind_hdr - __start_unwind_hdr);
+}
+
+static const u32 bad_cie, not_fde;
+static const u32 *cie_for_fde(const u32 *fde, const struct unwind_table *);
+static signed fde_pointer_type(const u32 *cie);
+
+struct eh_frame_hdr_table_entry {
+ unsigned long start, fde;
+};
+
+static int cmp_eh_frame_hdr_table_entries(const void *p1, const void *p2)
+{
+ const struct eh_frame_hdr_table_entry *e1 = p1;
+ const struct eh_frame_hdr_table_entry *e2 = p2;
+
+ return (e1->start > e2->start) - (e1->start < e2->start);
+}
+
+static void swap_eh_frame_hdr_table_entries(void *p1, void *p2, int size)
+{
+ struct eh_frame_hdr_table_entry *e1 = p1;
+ struct eh_frame_hdr_table_entry *e2 = p2;
+ unsigned long v;
+
+ v = e1->start;
+ e1->start = e2->start;
+ e2->start = v;
+ v = e1->fde;
+ e1->fde = e2->fde;
+ e2->fde = v;
+}
+
+static void __init setup_unwind_table(struct unwind_table *table,
+ void *(*alloc)(unsigned long))
+{
+ const u8 *ptr;
+ unsigned long tableSize = table->size, hdrSize;
+ unsigned n;
+ const u32 *fde;
+ struct {
+ u8 version;
+ u8 eh_frame_ptr_enc;
+ u8 fde_count_enc;
+ u8 table_enc;
+ unsigned long eh_frame_ptr;
+ unsigned int fde_count;
+ struct eh_frame_hdr_table_entry table[];
+ } __attribute__((__packed__)) *header;
+
+ if (table->header)
+ return;
+
+ if (table->hdrsz)
+ printk(KERN_WARNING ".eh_frame_hdr for '%s' present but unusable\n",
+ table->name);
+
+ if (tableSize & (sizeof(*fde) - 1))
+ return;
+
+ for (fde = table->address, n = 0;
+ tableSize > sizeof(*fde) && tableSize - sizeof(*fde) >= *fde;
+ tableSize -= sizeof(*fde) + *fde, fde += 1 + *fde / sizeof(*fde)) {
+ const u32 *cie = cie_for_fde(fde, table);
+ signed ptrType;
+
+ if (cie == &not_fde)
+ continue;
+ if (cie == NULL
+ || cie == &bad_cie
+ || (ptrType = fde_pointer_type(cie)) < 0)
+ return;
+ ptr = (const u8 *)(fde + 2);
+ if (!read_pointer(&ptr,
+ (const u8 *)(fde + 1) + *fde,
+ ptrType, 0, 0))
+ return;
+ ++n;
+ }
+
+ if (tableSize || !n)
+ return;
+
+ hdrSize = 4 + sizeof(unsigned long) + sizeof(unsigned int)
+ + 2 * n * sizeof(unsigned long);
+ dprintk(2, "Binary lookup table size for %s: %lu bytes", table->name, hdrSize);
+ header = alloc(hdrSize);
+ if (!header)
+ return;
+ header->version = 1;
+ header->eh_frame_ptr_enc = DW_EH_PE_abs|DW_EH_PE_native;
+ header->fde_count_enc = DW_EH_PE_abs|DW_EH_PE_data4;
+ header->table_enc = DW_EH_PE_abs|DW_EH_PE_native;
+ put_unaligned((unsigned long)table->address, &header->eh_frame_ptr);
+ BUILD_BUG_ON(offsetof(typeof(*header), fde_count)
+ % __alignof(typeof(header->fde_count)));
+ header->fde_count = n;
+
+ BUILD_BUG_ON(offsetof(typeof(*header), table)
+ % __alignof(typeof(*header->table)));
+ for (fde = table->address, tableSize = table->size, n = 0;
+ tableSize;
+ tableSize -= sizeof(*fde) + *fde, fde += 1 + *fde / sizeof(*fde)) {
+ const u32 *cie = fde + 1 - fde[1] / sizeof(*fde);
+
+ if (!fde[1])
+ continue; /* this is a CIE */
+ ptr = (const u8 *)(fde + 2);
+ header->table[n].start = read_pointer(&ptr,
+ (const u8 *)(fde + 1) + *fde,
+ fde_pointer_type(cie), 0, 0);
+ header->table[n].fde = (unsigned long)fde;
+ ++n;
+ }
+ WARN_ON(n != header->fde_count);
+
+ sort(header->table,
+ n,
+ sizeof(*header->table),
+ cmp_eh_frame_hdr_table_entries,
+ swap_eh_frame_hdr_table_entries);
+
+ table->hdrsz = hdrSize;
+ smp_wmb();
+ table->header = (const void *)header;
+}
+
+static void *__init balloc(unsigned long sz)
+{
+ return __alloc_bootmem_nopanic(sz,
+ sizeof(unsigned int),
+ __pa(MAX_DMA_ADDRESS));
+}
+
+void __init unwind_setup(void)
+{
+ setup_unwind_table(&root_table, balloc);
+}
+
+#ifdef CONFIG_MODULES
+
+static struct unwind_table *last_table;
+
+/* Must be called with module_mutex held. */
+void *unwind_add_table(struct module *module,
+ const void *table_start,
+ unsigned long table_size)
+{
+ struct unwind_table *table;
+
+ if (table_size <= 0)
+ return NULL;
+
+ table = kmalloc(sizeof(*table), GFP_KERNEL);
+ if (!table)
+ return NULL;
+
+ init_unwind_table(table, module->name,
+ module->module_core, module->core_size,
+ module->module_init, module->init_size,
+ table_start, table_size,
+ NULL, 0);
+
+ if (last_table)
+ last_table->link = table;
+ else
+ root_table.link = table;
+ last_table = table;
+
+ return table;
+}
+
+struct unlink_table_info
+{
+ struct unwind_table *table;
+ int init_only;
+};
+
+static int unlink_table(void *arg)
+{
+ struct unlink_table_info *info = arg;
+ struct unwind_table *table = info->table, *prev;
+
+ for (prev = &root_table; prev->link && prev->link != table; prev = prev->link)
+ ;
+
+ if (prev->link) {
+ if (info->init_only) {
+ table->init.pc = 0;
+ table->init.range = 0;
+ info->table = NULL;
+ } else {
+ prev->link = table->link;
+ if (!prev->link)
+ last_table = prev;
+ }
+ } else
+ info->table = NULL;
+
+ return 0;
+}
+
+/* Must be called with module_mutex held. */
+void unwind_remove_table(void *handle, int init_only)
+{
+ struct unwind_table *table = handle;
+ struct unlink_table_info info;
+
+ if (!table || table == &root_table)
+ return;
+
+ if (init_only && table == last_table) {
+ table->init.pc = 0;
+ table->init.range = 0;
+ return;
+ }
+
+ info.table = table;
+ info.init_only = init_only;
+ stop_machine(unlink_table, &info, NULL);
+
+ if (info.table)
+ kfree(table);
+}
+
+#endif /* CONFIG_MODULES */
+
+static uleb128_t get_uleb128(const u8 **pcur, const u8 *end)
+{
+ const u8 *cur = *pcur;
+ uleb128_t value;
+ unsigned shift;
+
+ for (shift = 0, value = 0; cur < end; shift += 7) {
+ if (shift + 7 > 8 * sizeof(value)
+ && (*cur & 0x7fU) >= (1U << (8 * sizeof(value) - shift))) {
+ cur = end + 1;
+ break;
+ }
+ value |= (uleb128_t)(*cur & 0x7f) << shift;
+ if (!(*cur++ & 0x80))
+ break;
+ }
+ *pcur = cur;
+
+ return value;
+}
+
+static sleb128_t get_sleb128(const u8 **pcur, const u8 *end)
+{
+ const u8 *cur = *pcur;
+ sleb128_t value;
+ unsigned shift;
+
+ for (shift = 0, value = 0; cur < end; shift += 7) {
+ if (shift + 7 > 8 * sizeof(value)
+ && (*cur & 0x7fU) >= (1U << (8 * sizeof(value) - shift))) {
+ cur = end + 1;
+ break;
+ }
+ value |= (sleb128_t)(*cur & 0x7f) << shift;
+ if (!(*cur & 0x80)) {
+ value |= -(*cur++ & 0x40) << shift;
+ break;
+ }
+ }
+ *pcur = cur;
+
+ return value;
+}
+
+static const u32 *cie_for_fde(const u32 *fde, const struct unwind_table *table)
+{
+ const u32 *cie;
+
+ if (!*fde || (*fde & (sizeof(*fde) - 1)))
+ return &bad_cie;
+ if (!fde[1])
+ return &not_fde; /* this is a CIE */
+ if ((fde[1] & (sizeof(*fde) - 1))
+ || fde[1] > (unsigned long)(fde + 1) - (unsigned long)table->address)
+ return NULL; /* this is not a valid FDE */
+ cie = fde + 1 - fde[1] / sizeof(*fde);
+ if (*cie <= sizeof(*cie) + 4
+ || *cie >= fde[1] - sizeof(*fde)
+ || (*cie & (sizeof(*cie) - 1))
+ || cie[1])
+ return NULL; /* this is not a (valid) CIE */
+ return cie;
+}
+
+static unsigned long read_pointer(const u8 **pLoc,
+ const void *end,
+ signed ptrType,
+ unsigned long text_base,
+ unsigned long data_base)
+{
+ unsigned long value = 0;
+ union {
+ const u8 *p8;
+ const u16 *p16u;
+ const s16 *p16s;
+ const u32 *p32u;
+ const s32 *p32s;
+ const unsigned long *pul;
+ } ptr;
+
+ if (ptrType < 0 || ptrType == DW_EH_PE_omit) {
+ dprintk(1, "Invalid pointer encoding %02X (%p,%p).", ptrType, *pLoc, end);
+ return 0;
+ }
+ ptr.p8 = *pLoc;
+ switch (ptrType & DW_EH_PE_FORM) {
+ case DW_EH_PE_data2:
+ if (end < (const void *)(ptr.p16u + 1)) {
+ dprintk(1, "Data16 overrun (%p,%p).", ptr.p8, end);
+ return 0;
+ }
+ if (ptrType & DW_EH_PE_signed)
+ value = get_unaligned(ptr.p16s++);
+ else
+ value = get_unaligned(ptr.p16u++);
+ break;
+ case DW_EH_PE_data4:
+#ifdef CONFIG_64BIT
+ if (end < (const void *)(ptr.p32u + 1)) {
+ dprintk(1, "Data32 overrun (%p,%p).", ptr.p8, end);
+ return 0;
+ }
+ if (ptrType & DW_EH_PE_signed)
+ value = get_unaligned(ptr.p32s++);
+ else
+ value = get_unaligned(ptr.p32u++);
+ break;
+ case DW_EH_PE_data8:
+ BUILD_BUG_ON(sizeof(u64) != sizeof(value));
+#else
+ BUILD_BUG_ON(sizeof(u32) != sizeof(value));
+#endif
+ case DW_EH_PE_native:
+ if (end < (const void *)(ptr.pul + 1)) {
+ dprintk(1, "DataUL overrun (%p,%p).", ptr.p8, end);
+ return 0;
+ }
+ value = get_unaligned(ptr.pul++);
+ break;
+ case DW_EH_PE_leb128:
+ BUILD_BUG_ON(sizeof(uleb128_t) > sizeof(value));
+ value = ptrType & DW_EH_PE_signed
+ ? get_sleb128(&ptr.p8, end)
+ : get_uleb128(&ptr.p8, end);
+ if ((const void *)ptr.p8 > end) {
+ dprintk(1, "DataLEB overrun (%p,%p).", ptr.p8, end);
+ return 0;
+ }
+ break;
+ default:
+ dprintk(2, "Cannot decode pointer type %02X (%p,%p).",
+ ptrType, ptr.p8, end);
+ return 0;
+ }
+ switch (ptrType & DW_EH_PE_ADJUST) {
+ case DW_EH_PE_abs:
+ break;
+ case DW_EH_PE_pcrel:
+ value += (unsigned long)*pLoc;
+ break;
+ case DW_EH_PE_textrel:
+ if (likely(text_base)) {
+ value += text_base;
+ break;
+ }
+ dprintk(2, "Text-relative encoding %02X (%p,%p), but zero text base.",
+ ptrType, *pLoc, end);
+ return 0;
+ case DW_EH_PE_datarel:
+ if (likely(data_base)) {
+ value += data_base;
+ break;
+ }
+ dprintk(2, "Data-relative encoding %02X (%p,%p), but zero data base.",
+ ptrType, *pLoc, end);
+ return 0;
+ default:
+ dprintk(2, "Cannot adjust pointer type %02X (%p,%p).",
+ ptrType, *pLoc, end);
+ return 0;
+ }
+ if ((ptrType & DW_EH_PE_indirect)
+ && probe_kernel_address(value, value)) {
+ dprintk(1, "Cannot read indirect value %lx (%p,%p).",
+ value, *pLoc, end);
+ return 0;
+ }
+ *pLoc = ptr.p8;
+
+ return value;
+}
+
+static signed fde_pointer_type(const u32 *cie)
+{
+ const u8 *ptr = (const u8 *)(cie + 2);
+ unsigned version = *ptr;
+
+ if (version != 1)
+ return -1; /* unsupported */
+ if (*++ptr) {
+ const char *aug;
+ const u8 *end = (const u8 *)(cie + 1) + *cie;
+ uleb128_t len;
+
+ /* check if augmentation size is first (and thus present) */
+ if (*ptr != 'z')
+ return -1;
+ /* check if augmentation string is nul-terminated */
+ if ((ptr = memchr(aug = (const void *)ptr, 0, end - ptr)) == NULL)
+ return -1;
+ ++ptr; /* skip terminator */
+ get_uleb128(&ptr, end); /* skip code alignment */
+ get_sleb128(&ptr, end); /* skip data alignment */
+ /* skip return address column */
+ version <= 1 ? (void)++ptr : (void)get_uleb128(&ptr, end);
+ len = get_uleb128(&ptr, end); /* augmentation length */
+ if (ptr + len < ptr || ptr + len > end)
+ return -1;
+ end = ptr + len;
+ while (*++aug) {
+ if (ptr >= end)
+ return -1;
+ switch (*aug) {
+ case 'L':
+ ++ptr;
+ break;
+ case 'P': {
+ signed ptrType = *ptr++;
+
+ if (!read_pointer(&ptr, end, ptrType, 0, 0)
+ || ptr > end)
+ return -1;
+ }
+ break;
+ case 'R':
+ return *ptr;
+ default:
+ return -1;
+ }
+ }
+ }
+ return DW_EH_PE_native|DW_EH_PE_abs;
+}
+
+static int advance_loc(unsigned long delta, struct unwind_state *state)
+{
+ state->loc += delta * state->codeAlign;
+
+ return delta > 0;
+}
+
+static void set_rule(uleb128_t reg,
+ enum item_location where,
+ uleb128_t value,
+ struct unwind_state *state)
+{
+ if (reg < ARRAY_SIZE(state->regs)) {
+ state->regs[reg].where = where;
+ state->regs[reg].value = value;
+ }
+}
+
+static int processCFI(const u8 *start,
+ const u8 *end,
+ unsigned long targetLoc,
+ signed ptrType,
+ struct unwind_state *state)
+{
+ union {
+ const u8 *p8;
+ const u16 *p16;
+ const u32 *p32;
+ } ptr;
+ int result = 1;
+
+ if (start != state->cieStart) {
+ state->loc = state->org;
+ result = processCFI(state->cieStart, state->cieEnd, 0, ptrType, state);
+ if (targetLoc == 0 && state->label == NULL)
+ return result;
+ }
+ for (ptr.p8 = start; result && ptr.p8 < end; ) {
+ switch (*ptr.p8 >> 6) {
+ uleb128_t value;
+
+ case 0:
+ switch (*ptr.p8++) {
+ case DW_CFA_nop:
+ break;
+ case DW_CFA_set_loc:
+ state->loc = read_pointer(&ptr.p8, end, ptrType, 0, 0);
+ if (state->loc == 0)
+ result = 0;
+ break;
+ case DW_CFA_advance_loc1:
+ result = ptr.p8 < end && advance_loc(*ptr.p8++, state);
+ break;
+ case DW_CFA_advance_loc2:
+ result = ptr.p8 <= end + 2
+ && advance_loc(*ptr.p16++, state);
+ break;
+ case DW_CFA_advance_loc4:
+ result = ptr.p8 <= end + 4
+ && advance_loc(*ptr.p32++, state);
+ break;
+ case DW_CFA_offset_extended:
+ value = get_uleb128(&ptr.p8, end);
+ set_rule(value, Memory, get_uleb128(&ptr.p8, end), state);
+ break;
+ case DW_CFA_val_offset:
+ value = get_uleb128(&ptr.p8, end);
+ set_rule(value, Value, get_uleb128(&ptr.p8, end), state);
+ break;
+ case DW_CFA_offset_extended_sf:
+ value = get_uleb128(&ptr.p8, end);
+ set_rule(value, Memory, get_sleb128(&ptr.p8, end), state);
+ break;
+ case DW_CFA_val_offset_sf:
+ value = get_uleb128(&ptr.p8, end);
+ set_rule(value, Value, get_sleb128(&ptr.p8, end), state);
+ break;
+ case DW_CFA_restore_extended:
+ case DW_CFA_undefined:
+ case DW_CFA_same_value:
+ set_rule(get_uleb128(&ptr.p8, end), Nowhere, 0, state);
+ break;
+ case DW_CFA_register:
+ value = get_uleb128(&ptr.p8, end);
+ set_rule(value,
+ Register,
+ get_uleb128(&ptr.p8, end), state);
+ break;
+ case DW_CFA_remember_state:
+ if (ptr.p8 == state->label) {
+ state->label = NULL;
+ return 1;
+ }
+ if (state->stackDepth >= MAX_STACK_DEPTH) {
+ dprintk(1, "State stack overflow (%p,%p).", ptr.p8, end);
+ return 0;
+ }
+ state->stack[state->stackDepth++] = ptr.p8;
+ break;
+ case DW_CFA_restore_state:
+ if (state->stackDepth) {
+ const uleb128_t loc = state->loc;
+ const u8 *label = state->label;
+
+ state->label = state->stack[state->stackDepth - 1];
+ memcpy(&state->cfa, &badCFA, sizeof(state->cfa));
+ memset(state->regs, 0, sizeof(state->regs));
+ state->stackDepth = 0;
+ result = processCFI(start, end, 0, ptrType, state);
+ state->loc = loc;
+ state->label = label;
+ } else {
+ dprintk(1, "State stack underflow (%p,%p).", ptr.p8, end);
+ return 0;
+ }
+ break;
+ case DW_CFA_def_cfa:
+ state->cfa.reg = get_uleb128(&ptr.p8, end);
+ /*nobreak*/
+ case DW_CFA_def_cfa_offset:
+ state->cfa.offs = get_uleb128(&ptr.p8, end);
+ break;
+ case DW_CFA_def_cfa_sf:
+ state->cfa.reg = get_uleb128(&ptr.p8, end);
+ /*nobreak*/
+ case DW_CFA_def_cfa_offset_sf:
+ state->cfa.offs = get_sleb128(&ptr.p8, end)
+ * state->dataAlign;
+ break;
+ case DW_CFA_def_cfa_register:
+ state->cfa.reg = get_uleb128(&ptr.p8, end);
+ break;
+ /*todo case DW_CFA_def_cfa_expression: */
+ /*todo case DW_CFA_expression: */
+ /*todo case DW_CFA_val_expression: */
+ case DW_CFA_GNU_args_size:
+ get_uleb128(&ptr.p8, end);
+ break;
+ case DW_CFA_GNU_negative_offset_extended:
+ value = get_uleb128(&ptr.p8, end);
+ set_rule(value,
+ Memory,
+ (uleb128_t)0 - get_uleb128(&ptr.p8, end), state);
+ break;
+ case DW_CFA_GNU_window_save:
+ default:
+ dprintk(1, "Unrecognized CFI op %02X (%p,%p).", ptr.p8[-1], ptr.p8 - 1, end);
+ result = 0;
+ break;
+ }
+ break;
+ case 1:
+ result = advance_loc(*ptr.p8++ & 0x3f, state);
+ break;
+ case 2:
+ value = *ptr.p8++ & 0x3f;
+ set_rule(value, Memory, get_uleb128(&ptr.p8, end), state);
+ break;
+ case 3:
+ set_rule(*ptr.p8++ & 0x3f, Nowhere, 0, state);
+ break;
+ }
+ if (ptr.p8 > end) {
+ dprintk(1, "Data overrun (%p,%p).", ptr.p8, end);
+ result = 0;
+ }
+ if (result && targetLoc != 0 && targetLoc < state->loc)
+ return 1;
+ }
+
+ if (result && ptr.p8 < end)
+ dprintk(1, "Data underrun (%p,%p).", ptr.p8, end);
+
+ return result
+ && ptr.p8 == end
+ && (targetLoc == 0
+ || (/*todo While in theory this should apply, gcc in practice omits
+ everything past the function prolog, and hence the location
+ never reaches the end of the function.
+ targetLoc < state->loc &&*/ state->label == NULL));
+}
+
+/* Unwind to previous to frame. Returns 0 if successful, negative
+ * number in case of an error. */
+int unwind(struct unwind_frame_info *frame)
+{
+#define FRAME_REG(r, t) (((t *)frame)[reg_info[r].offs])
+ const u32 *fde = NULL, *cie = NULL;
+ const u8 *ptr = NULL, *end = NULL;
+ unsigned long pc = UNW_PC(frame) - frame->call_frame, sp;
+ unsigned long startLoc = 0, endLoc = 0, cfa;
+ unsigned i;
+ signed ptrType = -1;
+ uleb128_t retAddrReg = 0;
+ const struct unwind_table *table;
+ struct unwind_state state;
+
+ if (UNW_PC(frame) == 0)
+ return -EINVAL;
+ if ((table = find_table(pc)) != NULL
+ && !(table->size & (sizeof(*fde) - 1))) {
+ const u8 *hdr = table->header;
+ unsigned long tableSize;
+
+ smp_rmb();
+ if (hdr && hdr[0] == 1) {
+ switch (hdr[3] & DW_EH_PE_FORM) {
+ case DW_EH_PE_native: tableSize = sizeof(unsigned long); break;
+ case DW_EH_PE_data2: tableSize = 2; break;
+ case DW_EH_PE_data4: tableSize = 4; break;
+ case DW_EH_PE_data8: tableSize = 8; break;
+ default: tableSize = 0; break;
+ }
+ ptr = hdr + 4;
+ end = hdr + table->hdrsz;
+ if (tableSize
+ && read_pointer(&ptr, end, hdr[1], 0, 0)
+ == (unsigned long)table->address
+ && (i = read_pointer(&ptr, end, hdr[2], 0, 0)) > 0
+ && i == (end - ptr) / (2 * tableSize)
+ && !((end - ptr) % (2 * tableSize))) {
+ do {
+ const u8 *cur = ptr + (i / 2) * (2 * tableSize);
+
+ startLoc = read_pointer(&cur,
+ cur + tableSize,
+ hdr[3], 0,
+ (unsigned long)hdr);
+ if (pc < startLoc)
+ i /= 2;
+ else {
+ ptr = cur - tableSize;
+ i = (i + 1) / 2;
+ }
+ } while (startLoc && i > 1);
+ if (i == 1
+ && (startLoc = read_pointer(&ptr,
+ ptr + tableSize,
+ hdr[3], 0,
+ (unsigned long)hdr)) != 0
+ && pc >= startLoc)
+ fde = (void *)read_pointer(&ptr,
+ ptr + tableSize,
+ hdr[3], 0,
+ (unsigned long)hdr);
+ }
+ }
+ if (hdr && !fde)
+ dprintk(3, "Binary lookup for %lx failed.", pc);
+
+ if (fde != NULL) {
+ cie = cie_for_fde(fde, table);
+ ptr = (const u8 *)(fde + 2);
+ if (cie != NULL
+ && cie != &bad_cie
+ && cie != &not_fde
+ && (ptrType = fde_pointer_type(cie)) >= 0
+ && read_pointer(&ptr,
+ (const u8 *)(fde + 1) + *fde,
+ ptrType, 0, 0) == startLoc) {
+ if (!(ptrType & DW_EH_PE_indirect))
+ ptrType &= DW_EH_PE_FORM|DW_EH_PE_signed;
+ endLoc = startLoc
+ + read_pointer(&ptr,
+ (const u8 *)(fde + 1) + *fde,
+ ptrType, 0, 0);
+ if (pc >= endLoc)
+ fde = NULL;
+ } else
+ fde = NULL;
+ if (!fde)
+ dprintk(1, "Binary lookup result for %lx discarded.", pc);
+ }
+ if (fde == NULL) {
+ for (fde = table->address, tableSize = table->size;
+ cie = NULL, tableSize > sizeof(*fde)
+ && tableSize - sizeof(*fde) >= *fde;
+ tableSize -= sizeof(*fde) + *fde,
+ fde += 1 + *fde / sizeof(*fde)) {
+ cie = cie_for_fde(fde, table);
+ if (cie == &bad_cie) {
+ cie = NULL;
+ break;
+ }
+ if (cie == NULL
+ || cie == &not_fde
+ || (ptrType = fde_pointer_type(cie)) < 0)
+ continue;
+ ptr = (const u8 *)(fde + 2);
+ startLoc = read_pointer(&ptr,
+ (const u8 *)(fde + 1) + *fde,
+ ptrType, 0, 0);
+ if (!startLoc)
+ continue;
+ if (!(ptrType & DW_EH_PE_indirect))
+ ptrType &= DW_EH_PE_FORM|DW_EH_PE_signed;
+ endLoc = startLoc
+ + read_pointer(&ptr,
+ (const u8 *)(fde + 1) + *fde,
+ ptrType, 0, 0);
+ if (pc >= startLoc && pc < endLoc)
+ break;
+ }
+ if (!fde)
+ dprintk(3, "Linear lookup for %lx failed.", pc);
+ }
+ }
+ if (cie != NULL) {
+ memset(&state, 0, sizeof(state));
+ state.cieEnd = ptr; /* keep here temporarily */
+ ptr = (const u8 *)(cie + 2);
+ end = (const u8 *)(cie + 1) + *cie;
+ frame->call_frame = 1;
+ if ((state.version = *ptr) != 1)
+ cie = NULL; /* unsupported version */
+ else if (*++ptr) {
+ /* check if augmentation size is first (and thus present) */
+ if (*ptr == 'z') {
+ while (++ptr < end && *ptr) {
+ switch (*ptr) {
+ /* check for ignorable (or already handled)
+ * nul-terminated augmentation string */
+ case 'L':
+ case 'P':
+ case 'R':
+ continue;
+ case 'S':
+ frame->call_frame = 0;
+ continue;
+ default:
+ break;
+ }
+ break;
+ }
+ }
+ if (ptr >= end || *ptr)
+ cie = NULL;
+ }
+ if (!cie)
+ dprintk(1, "CIE unusable (%p,%p).", ptr, end);
+ ++ptr;
+ }
+ if (cie != NULL) {
+ /* get code aligment factor */
+ state.codeAlign = get_uleb128(&ptr, end);
+ /* get data aligment factor */
+ state.dataAlign = get_sleb128(&ptr, end);
+ if (state.codeAlign == 0 || state.dataAlign == 0 || ptr >= end)
+ cie = NULL;
+ else if (UNW_PC(frame) % state.codeAlign
+ || UNW_SP(frame) % sleb128abs(state.dataAlign)) {
+ dprintk(1, "Input pointer(s) misaligned (%lx,%lx).",
+ UNW_PC(frame), UNW_SP(frame));
+ return -EPERM;
+ } else {
+ retAddrReg = state.version <= 1 ? *ptr++ : get_uleb128(&ptr, end);
+ /* skip augmentation */
+ if (((const char *)(cie + 2))[1] == 'z') {
+ uleb128_t augSize = get_uleb128(&ptr, end);
+
+ ptr += augSize;
+ }
+ if (ptr > end
+ || retAddrReg >= ARRAY_SIZE(reg_info)
+ || REG_INVALID(retAddrReg)
+ || reg_info[retAddrReg].width != sizeof(unsigned long))
+ cie = NULL;
+ }
+ if (!cie)
+ dprintk(1, "CIE validation failed (%p,%p).", ptr, end);
+ }
+ if (cie != NULL) {
+ state.cieStart = ptr;
+ ptr = state.cieEnd;
+ state.cieEnd = end;
+ end = (const u8 *)(fde + 1) + *fde;
+ /* skip augmentation */
+ if (((const char *)(cie + 2))[1] == 'z') {
+ uleb128_t augSize = get_uleb128(&ptr, end);
+
+ if ((ptr += augSize) > end)
+ fde = NULL;
+ }
+ if (!fde)
+ dprintk(1, "FDE validation failed (%p,%p).", ptr, end);
+ }
+#ifdef CONFIG_FRAME_POINTER
+ if (cie == NULL || fde == NULL) {
+ unsigned long top = TSK_STACK_TOP(frame->task);
+ unsigned long bottom = STACK_BOTTOM(frame->task);
+ unsigned long fp = UNW_FP(frame);
+ unsigned long sp = UNW_SP(frame);
+ unsigned long link;
+
+ if ((sp | fp) & sizeof(unsigned long))
+ return -EPERM;
+
+# if FRAME_RETADDR_OFFSET < 0
+ if (!(sp < top && fp <= sp && bottom < fp))
+# else
+ if (!(sp < top && fp >= sp && bottom < fp))
+# endif
+ return -ENXIO;
+
+ if (probe_kernel_address(fp + FRAME_LINK_OFFSET, link))
+ return -ENXIO;
+
+# if FRAME_RETADDR_OFFSET < 0
+ if (!(link > bottom && link < fp))
+# else
+ if (!(link > bottom && link > fp))
+# endif
+ return -ENXIO;
+
+ if (link & (sizeof(unsigned long) - 1))
+ return -ENXIO;
+
+ fp += FRAME_RETADDR_OFFSET;
+ if (probe_kernel_address(fp, UNW_PC(frame)))
+ return -ENXIO;
+
+ /* Ok, we can use it */
+# if FRAME_RETADDR_OFFSET < 0
+ UNW_SP(frame) = fp - sizeof(UNW_PC(frame));
+# else
+ UNW_SP(frame) = fp + sizeof(UNW_PC(frame));
+# endif
+ UNW_FP(frame) = link;
+ return 0;
+ }
+#endif
+ state.org = startLoc;
+ memcpy(&state.cfa, &badCFA, sizeof(state.cfa));
+ /* process instructions */
+ if (!processCFI(ptr, end, pc, ptrType, &state)
+ || state.loc > endLoc
+ || state.regs[retAddrReg].where == Nowhere
+ || state.cfa.reg >= ARRAY_SIZE(reg_info)
+ || reg_info[state.cfa.reg].width != sizeof(unsigned long)
+ || FRAME_REG(state.cfa.reg, unsigned long) % sizeof(unsigned long)
+ || state.cfa.offs % sizeof(unsigned long)) {
+ dprintk(1, "Unusable unwind info (%p,%p).", ptr, end);
+ return -EIO;
+ }
+ /* update frame */
+#ifndef CONFIG_AS_CFI_SIGNAL_FRAME
+ if (frame->call_frame
+ && !UNW_DEFAULT_RA(state.regs[retAddrReg], state.dataAlign))
+ frame->call_frame = 0;
+#endif
+ cfa = FRAME_REG(state.cfa.reg, unsigned long) + state.cfa.offs;
+ startLoc = min((unsigned long)UNW_SP(frame), cfa);
+ endLoc = max((unsigned long)UNW_SP(frame), cfa);
+ if (STACK_LIMIT(startLoc) != STACK_LIMIT(endLoc)) {
+ startLoc = min(STACK_LIMIT(cfa), cfa);
+ endLoc = max(STACK_LIMIT(cfa), cfa);
+ }
+#ifndef CONFIG_64BIT
+# define CASES CASE(8); CASE(16); CASE(32)
+#else
+# define CASES CASE(8); CASE(16); CASE(32); CASE(64)
+#endif
+ pc = UNW_PC(frame);
+ sp = UNW_SP(frame);
+ for (i = 0; i < ARRAY_SIZE(state.regs); ++i) {
+ if (REG_INVALID(i)) {
+ if (state.regs[i].where == Nowhere)
+ continue;
+ dprintk(1, "Cannot restore register %u (%d).",
+ i, state.regs[i].where);
+ return -EIO;
+ }
+ switch (state.regs[i].where) {
+ default:
+ break;
+ case Register:
+ if (state.regs[i].value >= ARRAY_SIZE(reg_info)
+ || REG_INVALID(state.regs[i].value)
+ || reg_info[i].width > reg_info[state.regs[i].value].width) {
+ dprintk(1, "Cannot restore register %u from register %lu.",
+ i, state.regs[i].value);
+ return -EIO;
+ }
+ switch (reg_info[state.regs[i].value].width) {
+#define CASE(n) \
+ case sizeof(u##n): \
+ state.regs[i].value = FRAME_REG(state.regs[i].value, \
+ const u##n); \
+ break
+ CASES;
+#undef CASE
+ default:
+ dprintk(1, "Unsupported register size %u (%lu).",
+ reg_info[state.regs[i].value].width,
+ state.regs[i].value);
+ return -EIO;
+ }
+ break;
+ }
+ }
+ for (i = 0; i < ARRAY_SIZE(state.regs); ++i) {
+ if (REG_INVALID(i))
+ continue;
+ switch (state.regs[i].where) {
+ case Nowhere:
+ if (reg_info[i].width != sizeof(UNW_SP(frame))
+ || &FRAME_REG(i, __typeof__(UNW_SP(frame)))
+ != &UNW_SP(frame))
+ continue;
+ UNW_SP(frame) = cfa;
+ break;
+ case Register:
+ switch (reg_info[i].width) {
+#define CASE(n) case sizeof(u##n): \
+ FRAME_REG(i, u##n) = state.regs[i].value; \
+ break
+ CASES;
+#undef CASE
+ default:
+ dprintk(1, "Unsupported register size %u (%u).",
+ reg_info[i].width, i);
+ return -EIO;
+ }
+ break;
+ case Value:
+ if (reg_info[i].width != sizeof(unsigned long)) {
+ dprintk(1, "Unsupported value size %u (%u).",
+ reg_info[i].width, i);
+ return -EIO;
+ }
+ FRAME_REG(i, unsigned long) = cfa + state.regs[i].value
+ * state.dataAlign;
+ break;
+ case Memory: {
+ unsigned long addr = cfa + state.regs[i].value
+ * state.dataAlign;
+
+ if ((state.regs[i].value * state.dataAlign)
+ % sizeof(unsigned long)
+ || addr < startLoc
+ || addr + sizeof(unsigned long) < addr
+ || addr + sizeof(unsigned long) > endLoc) {
+ dprintk(1, "Bad memory location %lx (%lx).",
+ addr, state.regs[i].value);
+ return -EIO;
+ }
+ switch (reg_info[i].width) {
+#define CASE(n) case sizeof(u##n): \
+ if (probe_kernel_address(addr, \
+ FRAME_REG(i, u##n))) \
+ return -EFAULT; \
+ break
+ CASES;
+#undef CASE
+ default:
+ dprintk(1, "Unsupported memory size %u (%u).",
+ reg_info[i].width, i);
+ return -EIO;
+ }
+ }
+ break;
+ }
+ }
+
+ if (UNW_PC(frame) % state.codeAlign
+ || UNW_SP(frame) % sleb128abs(state.dataAlign)) {
+ dprintk(1, "Output pointer(s) misaligned (%lx,%lx).",
+ UNW_PC(frame), UNW_SP(frame));
+ return -EIO;
+ }
+ if (pc == UNW_PC(frame) && sp == UNW_SP(frame)) {
+ dprintk(1, "No progress (%lx,%lx).", pc, sp);
+ return -EIO;
+ }
+
+ return 0;
+#undef CASES
+#undef FRAME_REG
+}
+EXPORT_SYMBOL_GPL(unwind);
+
+int unwind_init_frame_info(struct unwind_frame_info *info,
+ struct task_struct *tsk,
+ /*const*/ struct pt_regs *regs)
+{
+ info->task = tsk;
+ info->call_frame = 0;
+ arch_unw_init_frame_info(info, regs);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(unwind_init_frame_info);
+
+/*
+ * Prepare to unwind a blocked task.
+ */
+int unwind_init_blocked(struct unwind_frame_info *info,
+ struct task_struct *tsk)
+{
+ info->task = tsk;
+ info->call_frame = 0;
+ arch_unw_init_blocked(info);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(unwind_init_blocked);
+
+/*
+ * Prepare to unwind the currently running thread.
+ */
+int unwind_init_running(struct unwind_frame_info *info,
+ asmlinkage unwind_callback_fn callback,
+ const struct stacktrace_ops *ops, void *data)
+{
+ info->task = current;
+ info->call_frame = 0;
+
+ return arch_unwind_init_running(info, callback, ops, data);
+}
+EXPORT_SYMBOL_GPL(unwind_init_running);
+
+/*
+ * Unwind until the return pointer is in user-land (or until an error
+ * occurs). Returns 0 if successful, negative number in case of
+ * error.
+ */
+int unwind_to_user(struct unwind_frame_info *info)
+{
+ while (!arch_unw_user_mode(info)) {
+ int err = unwind(info);
+
+ if (err < 0)
+ return err;
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(unwind_to_user);
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -742,6 +742,24 @@ config FRAME_POINTER
larger and slower, but it gives very useful debugging information
in case of kernel bugs. (precise oopses/stacktraces/warnings)
+config UNWIND_INFO
+ bool "Compile the kernel with frame unwind information"
+ depends on !IA64 && !PARISC && !ARM
+ depends on !MODULES || !(MIPS || PPC || SUPERH || V850)
+ help
+ If you say Y here the resulting kernel image will be slightly larger
+ but not slower, and it will give very useful debugging information.
+ If you don't debug the kernel, you can say N, but we may not be able
+ to solve problems without frame unwind information or frame pointers.
+
+config STACK_UNWIND
+ bool "Stack unwind support"
+ depends on UNWIND_INFO
+ depends on X86
+ help
+ This enables more precise stack traces, omitting all unrelated
+ occurrences of pointers into kernel code from the dump.
+
config BOOT_PRINTK_DELAY
bool "Delay each boot printk message by N milliseconds"
depends on DEBUG_KERNEL && PRINTK && GENERIC_CALIBRATE_DELAY
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