Remove stack unwinder for now

It has caused more problems than it ever really solved, and is
apparently not getting cleaned up and fixed.  We can put it back when
it's stable and isn't likely to make warning or bug events worse.

In the meantime, enable frame pointers for more readable stack traces.

Signed-off-by: Linus Torvalds <torvalds@osdl.org>

4 files changed, 2 insertions, 270 deletions

diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
index 7437cca..1587121 100644
--- a/include/asm-generic/vmlinux.lds.h
+++ b/include/asm-generic/vmlinux.lds.h
@@ -119,8 +119,6 @@
 		*(__ksymtab_strings)					\
 	}								\
 									\
-	EH_FRAME							\
-									\
 	/* Built-in module parameters. */				\
 	__param : AT(ADDR(__param) - LOAD_OFFSET) {			\
 		VMLINUX_SYMBOL(__start___param) = .;			\
@@ -160,26 +158,6 @@
 		*(.kprobes.text)					\
 		VMLINUX_SYMBOL(__kprobes_text_end) = .;
 
-#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
-
 		/* DWARF debug sections.
 		Symbols in the DWARF debugging sections are relative to
 		the beginning of the section so we begin them at 0.  */
diff --git a/include/asm-i386/unwind.h b/include/asm-i386/unwind.h
index aa2c931..43c70c3 100644
--- a/include/asm-i386/unwind.h
+++ b/include/asm-i386/unwind.h
@@ -1,95 +1,6 @@
 #ifndef _ASM_I386_UNWIND_H
 #define _ASM_I386_UNWIND_H
 
-/*
- * Copyright (C) 2002-2006 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 <asm/fixmap.h>
-#include <asm/ptrace.h>
-#include <asm/uaccess.h>
-
-struct unwind_frame_info
-{
-	struct pt_regs regs;
-	struct task_struct *task;
-	unsigned call_frame:1;
-};
-
-#define UNW_PC(frame)        (frame)->regs.eip
-#define UNW_SP(frame)        (frame)->regs.esp
-#ifdef CONFIG_FRAME_POINTER
-#define UNW_FP(frame)        (frame)->regs.ebp
-#define FRAME_RETADDR_OFFSET 4
-#define FRAME_LINK_OFFSET    0
-#define STACK_BOTTOM(tsk)    STACK_LIMIT((tsk)->thread.esp0)
-#define STACK_TOP(tsk)       ((tsk)->thread.esp0)
-#else
-#define UNW_FP(frame) ((void)(frame), 0)
-#endif
-#define STACK_LIMIT(ptr)     (((ptr) - 1) & ~(THREAD_SIZE - 1))
-
-#define UNW_REGISTER_INFO \
-	PTREGS_INFO(eax), \
-	PTREGS_INFO(ecx), \
-	PTREGS_INFO(edx), \
-	PTREGS_INFO(ebx), \
-	PTREGS_INFO(esp), \
-	PTREGS_INFO(ebp), \
-	PTREGS_INFO(esi), \
-	PTREGS_INFO(edi), \
-	PTREGS_INFO(eip)
-
-#define UNW_DEFAULT_RA(raItem, dataAlign) \
-	((raItem).where == Memory && \
-	 !((raItem).value * (dataAlign) + 4))
-
-static inline void arch_unw_init_frame_info(struct unwind_frame_info *info,
-                                            /*const*/ struct pt_regs *regs)
-{
-	if (user_mode_vm(regs))
-		info->regs = *regs;
-	else {
-		memcpy(&info->regs, regs, offsetof(struct pt_regs, esp));
-		info->regs.esp = (unsigned long)&regs->esp;
-		info->regs.xss = __KERNEL_DS;
-	}
-}
-
-static inline void arch_unw_init_blocked(struct unwind_frame_info *info)
-{
-	memset(&info->regs, 0, sizeof(info->regs));
-	info->regs.eip = info->task->thread.eip;
-	info->regs.xcs = __KERNEL_CS;
-	__get_user(info->regs.ebp, (long *)info->task->thread.esp);
-	info->regs.esp = info->task->thread.esp;
-	info->regs.xss = __KERNEL_DS;
-	info->regs.xds = __USER_DS;
-	info->regs.xes = __USER_DS;
-	info->regs.xgs = __KERNEL_PDA;
-}
-
-extern asmlinkage int arch_unwind_init_running(struct unwind_frame_info *,
-                                               asmlinkage int (*callback)(struct unwind_frame_info *,
-                                                                          void *arg),
-                                               void *arg);
-
-static inline int arch_unw_user_mode(/*const*/ struct unwind_frame_info *info)
-{
-	return user_mode_vm(&info->regs)
-	       || info->regs.eip < PAGE_OFFSET
-	       || (info->regs.eip >= __fix_to_virt(FIX_VDSO)
-	           && info->regs.eip < __fix_to_virt(FIX_VDSO) + PAGE_SIZE)
-	       || info->regs.esp < PAGE_OFFSET;
-}
-
-#else
-
 #define UNW_PC(frame) ((void)(frame), 0)
 #define UNW_SP(frame) ((void)(frame), 0)
 #define UNW_FP(frame) ((void)(frame), 0)
@@ -99,6 +10,4 @@ static inline int arch_unw_user_mode(const void *info)
 	return 0;
 }
 
-#endif
-
 #endif /* _ASM_I386_UNWIND_H */
diff --git a/include/asm-x86_64/unwind.h b/include/asm-x86_64/unwind.h
index 2f6349e..02710f6 100644
--- a/include/asm-x86_64/unwind.h
+++ b/include/asm-x86_64/unwind.h
@@ -1,100 +1,6 @@
 #ifndef _ASM_X86_64_UNWIND_H
 #define _ASM_X86_64_UNWIND_H
 
-/*
- * Copyright (C) 2002-2006 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 <asm/ptrace.h>
-#include <asm/uaccess.h>
-#include <asm/vsyscall.h>
-
-struct unwind_frame_info
-{
-	struct pt_regs regs;
-	struct task_struct *task;
-	unsigned call_frame:1;
-};
-
-#define UNW_PC(frame)        (frame)->regs.rip
-#define UNW_SP(frame)        (frame)->regs.rsp
-#ifdef CONFIG_FRAME_POINTER
-#define UNW_FP(frame)        (frame)->regs.rbp
-#define FRAME_RETADDR_OFFSET 8
-#define FRAME_LINK_OFFSET    0
-#define STACK_BOTTOM(tsk)    (((tsk)->thread.rsp0 - 1) & ~(THREAD_SIZE - 1))
-#define STACK_TOP(tsk)       ((tsk)->thread.rsp0)
-#endif
-/* 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))
-
-#define UNW_REGISTER_INFO \
-	PTREGS_INFO(rax), \
-	PTREGS_INFO(rdx), \
-	PTREGS_INFO(rcx), \
-	PTREGS_INFO(rbx), \
-	PTREGS_INFO(rsi), \
-	PTREGS_INFO(rdi), \
-	PTREGS_INFO(rbp), \
-	PTREGS_INFO(rsp), \
-	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(rip)
-
-#define UNW_DEFAULT_RA(raItem, dataAlign) \
-	((raItem).where == Memory && \
-	 !((raItem).value * (dataAlign) + 8))
-
-static inline void arch_unw_init_frame_info(struct unwind_frame_info *info,
-                                            /*const*/ struct pt_regs *regs)
-{
-	info->regs = *regs;
-}
-
-static inline void arch_unw_init_blocked(struct unwind_frame_info *info)
-{
-	extern const char thread_return[];
-
-	memset(&info->regs, 0, sizeof(info->regs));
-	info->regs.rip = (unsigned long)thread_return;
-	info->regs.cs = __KERNEL_CS;
-	__get_user(info->regs.rbp, (unsigned long *)info->task->thread.rsp);
-	info->regs.rsp = info->task->thread.rsp;
-	info->regs.ss = __KERNEL_DS;
-}
-
-extern int arch_unwind_init_running(struct unwind_frame_info *,
-                                    int (*callback)(struct unwind_frame_info *,
-                                                    void *arg),
-                                    void *arg);
-
-static inline int arch_unw_user_mode(const struct unwind_frame_info *info)
-{
-	return user_mode(&info->regs)
-	       || (long)info->regs.rip >= 0
-	       || (info->regs.rip >= VSYSCALL_START && info->regs.rip < VSYSCALL_END)
-	       || (long)info->regs.rsp >= 0;
-}
-
-#else
-
 #define UNW_PC(frame) ((void)(frame), 0UL)
 #define UNW_SP(frame) ((void)(frame), 0UL)
 
@@ -103,6 +9,4 @@ static inline int arch_unw_user_mode(const void *info)
 	return 0;
 }
 
-#endif
-
 #endif /* _ASM_X86_64_UNWIND_H */
diff --git a/include/linux/unwind.h b/include/linux/unwind.h
index 749928c..7760860 100644
--- a/include/linux/unwind.h
+++ b/include/linux/unwind.h
@@ -14,63 +14,6 @@
 
 struct module;
 
-#ifdef CONFIG_STACK_UNWIND
-
-#include <asm/unwind.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 *,
-                               asmlinkage int (*callback)(struct unwind_frame_info *,
-                                                          void *arg),
-                               void *arg);
-
-/*
- * 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
-
 struct unwind_frame_info {};
 
 static inline void unwind_init(void) {}
@@ -85,12 +28,12 @@ static inline void *unwind_add_table(struct module *mod,
 	return NULL;
 }
 
-#endif
-
 static inline void unwind_remove_table(void *handle, int init_only)
 {
 }
 
+#endif
+
 static inline int unwind_init_frame_info(struct unwind_frame_info *info,
                                          struct task_struct *tsk,
                                          const struct pt_regs *regs)
@@ -122,6 +65,4 @@ static inline int unwind_to_user(struct unwind_frame_info *info)
 	return -ENOSYS;
 }
 
-#endif
-
 #endif /* _LINUX_UNWIND_H */