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>
diff --git a/arch/x86/include/asm/linkage.h b/arch/x86/include/asm/linkage.h
index f61ee8f..5d98d0b 100644
--- a/arch/x86/include/asm/linkage.h
+++ b/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; \
+ __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 */