lkml.org 
[lkml]   [2008]   [Nov]   [23]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[RFC -tip] x86: introduce ENTRY(KPROBE)_X86 assembly helpers to catch unbalanced declaration
It's usefull to catch unbalanced, missed or mixed declarations of ENTRY and
KPROBES. These macros would help a bit (at least I hope so).

For example the following code would compile without problems

ENTRY_X86(mcount)
retq
END_X86(mcount)

But if you forget and mix 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>
---
arch/x86/include/asm/linkage.h | 60 +++++++++++++++++++++++++++++++++++++++++
1 file changed, 60 insertions(+)
Index: linux-2.6.git/arch/x86/include/asm/linkage.h
===================================================================
--- linux-2.6.git.orig/arch/x86/include/asm/linkage.h
+++ linux-2.6.git/arch/x86/include/asm/linkage.h
@@ -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; \
+ __x86_macro_err; \
+ .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 */


\
 
 \ /
  Last update: 2008-11-23 17:59    [from the cache]
©2003-2011 Jasper Spaans