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>
61 lines
1.6 KiB
C
61 lines
1.6 KiB
C
#ifndef _DWARF2_H
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#define _DWARF2_H
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#ifndef __ASSEMBLY__
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#warning "asm/dwarf2.h should be only included in pure assembly files"
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#endif
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/*
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Macros for dwarf2 CFI unwind table entries.
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See "as.info" for details on these pseudo ops. Unfortunately
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they are only supported in very new binutils, so define them
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away for older version.
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*/
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#ifdef CONFIG_UNWIND_INFO
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#define CFI_STARTPROC .cfi_startproc
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#define CFI_ENDPROC .cfi_endproc
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#define CFI_DEF_CFA .cfi_def_cfa
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#define CFI_DEF_CFA_REGISTER .cfi_def_cfa_register
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#define CFI_DEF_CFA_OFFSET .cfi_def_cfa_offset
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#define CFI_ADJUST_CFA_OFFSET .cfi_adjust_cfa_offset
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#define CFI_OFFSET .cfi_offset
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#define CFI_REL_OFFSET .cfi_rel_offset
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#define CFI_REGISTER .cfi_register
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#define CFI_RESTORE .cfi_restore
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#define CFI_REMEMBER_STATE .cfi_remember_state
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#define CFI_RESTORE_STATE .cfi_restore_state
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#define CFI_UNDEFINED .cfi_undefined
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#ifdef CONFIG_AS_CFI_SIGNAL_FRAME
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#define CFI_SIGNAL_FRAME .cfi_signal_frame
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#else
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#define CFI_SIGNAL_FRAME
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#endif
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#else
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/* Due to the structure of pre-exisiting code, don't use assembler line
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comment character # to ignore the arguments. Instead, use a dummy macro. */
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.macro ignore a=0, b=0, c=0, d=0
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.endm
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#define CFI_STARTPROC ignore
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#define CFI_ENDPROC ignore
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#define CFI_DEF_CFA ignore
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#define CFI_DEF_CFA_REGISTER ignore
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#define CFI_DEF_CFA_OFFSET ignore
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#define CFI_ADJUST_CFA_OFFSET ignore
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#define CFI_OFFSET ignore
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#define CFI_REL_OFFSET ignore
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#define CFI_REGISTER ignore
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#define CFI_RESTORE ignore
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#define CFI_REMEMBER_STATE ignore
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#define CFI_RESTORE_STATE ignore
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#define CFI_UNDEFINED ignore
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#define CFI_SIGNAL_FRAME ignore
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#endif
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#endif
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