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Commit 3b6c52b5 authored by Cyrill Gorcunov's avatar Cyrill Gorcunov Committed by Ingo Molnar
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x86: introduce ENTRY(KPROBE_ENTRY)_X86 assembly helpers to catch unbalanced declaration v3 



Impact: make ENTRY()/END() macros more capable

It's usefull to catch unbalanced or messed or mixed declarations of ENTRY and
KPROBES. These macros would help a bit.

For example the following code would compile without problems

        ENTRY_X86(mcount)
                retq
        END_X86(mcount)

But if you forget and mess the following form

        ENTRY_X86(mcount)
                retq
        END(mcount)

        ENTRY_X86(ftrace_caller)

The assembler will issue the following message:
Error: ENTRY_X86/KPROBE_X86 unbalanced,missed,mixed

Actually the checking is performed at every _X86 macro
so maybe it's good idea to put ENTRY_KPROBE_FINAL_X86
at the end of .S file to be sure you didn't miss anything.

Signed-off-by: default avatarCyrill Gorcunov <gorcunov@gmail.com>
Cc: Alexander van Heukelum <heukelum@mailshack.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 6efdcfaf

arch/x86/include/asm/linkage.h

+60 −0
Original line number Diff line number Diff line
@@ -57,5 +57,65 @@ 
#define __ALIGN_STR ".align 16,0x90"

#endif



/*

 * to check ENTRY_X86/END_X86 and

 * KPROBE_ENTRY_X86/KPROBE_END_X86

 * unbalanced-missed-mixed appearance

 */

#define __set_entry_x86		.set ENTRY_X86_IN, 0

#define __unset_entry_x86	.set ENTRY_X86_IN, 1

#define __set_kprobe_x86	.set KPROBE_X86_IN, 0

#define __unset_kprobe_x86	.set KPROBE_X86_IN, 1



#define __macro_err_x86 .error "ENTRY_X86/KPROBE_X86 unbalanced,missed,mixed"



#define __check_entry_x86	\

	.ifdef ENTRY_X86_IN;	\

	.ifeq ENTRY_X86_IN;	\

	__macro_err_x86;	\

	.abort;			\

	.endif;			\

	.endif



#define __check_kprobe_x86	\

	.ifdef KPROBE_X86_IN;	\

	.ifeq KPROBE_X86_IN;	\

	__macro_err_x86;	\

	.abort;			\

	.endif;			\

	.endif



#define __check_entry_kprobe_x86	\

	__check_entry_x86;		\

	__check_kprobe_x86



#define ENTRY_KPROBE_FINAL_X86 __check_entry_kprobe_x86



#define ENTRY_X86(name)			\

	__check_entry_kprobe_x86;	\

	__set_entry_x86;		\

	.globl name;			\

	__ALIGN;			\

	name:



#define END_X86(name)			\

	__unset_entry_x86;		\

	__check_entry_kprobe_x86;	\

	.size name, .-name



#define KPROBE_ENTRY_X86(name)		\

	__check_entry_kprobe_x86;	\

	__set_kprobe_x86;		\

	.pushsection .kprobes.text, "ax"; \

	.globl name;			\

	__ALIGN;			\

	name:



#define KPROBE_END_X86(name)		\

	__unset_kprobe_x86;		\

	__check_entry_kprobe_x86;	\

	.size name, .-name;		\

	.popsection



#endif /* _ASM_X86_LINKAGE_H */