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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: Cyrill Gorcunov <gorcunov@gmail.com>
Cc: Alexander van Heukelum <heukelum@mailshack.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Cyrill Gorcunov 2008-11-23 20:21:39 +03:00 committed by Ingo Molnar
parent 6efdcfaf16
commit 3b6c52b5b6
1 changed files with 60 additions and 0 deletions
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60
arch/x86/include/asm/linkage.h
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@ -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 */