adf1423698
Current gcc generates calls not jumps to noreturn functions. When that happens the return address can point to the next function, which confuses the unwinder. This patch works around it by marking asynchronous exception frames in contrast normal call frames in the unwind information. Then teach the unwinder to decode this. For normal call frames the unwinder now subtracts one from the address which avoids this problem. The standard libgcc unwinder uses the same trick. It doesn't include adjustment of the printed address (i.e. for the original example, it'd still be kernel_math_error+0 that gets displayed, but the unwinder wouldn't get confused anymore. This only works with binutils 2.6.17+ and some versions of H.J.Lu's 2.6.16 unfortunately because earlier binutils don't support .cfi_signal_frame [AK: added automatic detection of the new binutils and wrote description] Signed-off-by: Jan Beulich <jbeulich@novell.com> Signed-off-by: Andi Kleen <ak@suse.de>
107 lines
2.9 KiB
C
107 lines
2.9 KiB
C
#ifndef _ASM_I386_UNWIND_H
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#define _ASM_I386_UNWIND_H
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/*
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* Copyright (C) 2002-2006 Novell, Inc.
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* Jan Beulich <jbeulich@novell.com>
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* This code is released under version 2 of the GNU GPL.
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*/
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#ifdef CONFIG_STACK_UNWIND
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#include <linux/sched.h>
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#include <asm/fixmap.h>
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#include <asm/ptrace.h>
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#include <asm/uaccess.h>
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struct unwind_frame_info
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{
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struct pt_regs regs;
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struct task_struct *task;
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unsigned call_frame:1;
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};
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#define UNW_PC(frame) (frame)->regs.eip
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#define UNW_SP(frame) (frame)->regs.esp
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#ifdef CONFIG_FRAME_POINTER
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#define UNW_FP(frame) (frame)->regs.ebp
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#define FRAME_RETADDR_OFFSET 4
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#define FRAME_LINK_OFFSET 0
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#define STACK_BOTTOM(tsk) STACK_LIMIT((tsk)->thread.esp0)
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#define STACK_TOP(tsk) ((tsk)->thread.esp0)
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#else
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#define UNW_FP(frame) ((void)(frame), 0)
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#endif
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#define STACK_LIMIT(ptr) (((ptr) - 1) & ~(THREAD_SIZE - 1))
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#define UNW_REGISTER_INFO \
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PTREGS_INFO(eax), \
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PTREGS_INFO(ecx), \
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PTREGS_INFO(edx), \
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PTREGS_INFO(ebx), \
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PTREGS_INFO(esp), \
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PTREGS_INFO(ebp), \
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PTREGS_INFO(esi), \
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PTREGS_INFO(edi), \
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PTREGS_INFO(eip)
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#define UNW_DEFAULT_RA(raItem, dataAlign) \
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((raItem).where == Memory && \
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!((raItem).value * (dataAlign) + 4))
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static inline void arch_unw_init_frame_info(struct unwind_frame_info *info,
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/*const*/ struct pt_regs *regs)
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{
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if (user_mode_vm(regs))
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info->regs = *regs;
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else {
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memcpy(&info->regs, regs, offsetof(struct pt_regs, esp));
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info->regs.esp = (unsigned long)®s->esp;
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info->regs.xss = __KERNEL_DS;
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}
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}
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static inline void arch_unw_init_blocked(struct unwind_frame_info *info)
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{
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memset(&info->regs, 0, sizeof(info->regs));
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info->regs.eip = info->task->thread.eip;
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info->regs.xcs = __KERNEL_CS;
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__get_user(info->regs.ebp, (long *)info->task->thread.esp);
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info->regs.esp = info->task->thread.esp;
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info->regs.xss = __KERNEL_DS;
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info->regs.xds = __USER_DS;
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info->regs.xes = __USER_DS;
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}
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extern asmlinkage int arch_unwind_init_running(struct unwind_frame_info *,
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asmlinkage int (*callback)(struct unwind_frame_info *,
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void *arg),
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void *arg);
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static inline int arch_unw_user_mode(const struct unwind_frame_info *info)
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{
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#if 0 /* This can only work when selector register and EFLAGS saves/restores
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are properly annotated (and tracked in UNW_REGISTER_INFO). */
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return user_mode_vm(&info->regs);
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#else
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return info->regs.eip < PAGE_OFFSET
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|| (info->regs.eip >= __fix_to_virt(FIX_VDSO)
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&& info->regs.eip < __fix_to_virt(FIX_VDSO) + PAGE_SIZE)
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|| info->regs.esp < PAGE_OFFSET;
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#endif
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}
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#else
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#define UNW_PC(frame) ((void)(frame), 0)
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#define UNW_SP(frame) ((void)(frame), 0)
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#define UNW_FP(frame) ((void)(frame), 0)
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static inline int arch_unw_user_mode(const void *info)
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{
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return 0;
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}
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#endif
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#endif /* _ASM_I386_UNWIND_H */
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