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authorPrasanna S.P <prasanna@in.ibm.com>2006-09-26 04:52:34 -0400
committerAndi Kleen <andi@basil.nowhere.org>2006-09-26 04:52:34 -0400
commitd28c4393a7bf558538e9def269c1caeab6ec056f (patch)
treee5319c9b9c8a75d2290f7429ec84884d7e1a91fe /include/linux/linkage.h
parent3ca113ea74836a80645c79adba24caaa7a74120c (diff)
[PATCH] x86: error_code is not safe for kprobes
This patch moves the entry.S:error_entry to .kprobes.text section, since code marked unsafe for kprobes jumps directly to entry.S::error_entry, that must be marked unsafe as well. This patch also moves all the ".previous.text" asm directives to ".previous" for kprobes section. AK: Following a similar i386 patch from Chuck Ebbert AK: Also merged Jeremy's fix in. +From: Jeremy Fitzhardinge <jeremy@goop.org> KPROBE_ENTRY does a .section .kprobes.text, and expects its users to do a .previous at the end of the function. Unfortunately, if any code within the function switches sections, for example .fixup, then the .previous ends up putting all subsequent code into .fixup. Worse, any subsequent .fixup code gets intermingled with the code its supposed to be fixing (which is also in .fixup). It's surprising this didn't cause more havok. The fix is to use .pushsection/.popsection, so this stuff nests properly. A further cleanup would be to get rid of all .section/.previous pairs, since they're inherently fragile. +From: Chuck Ebbert <76306.1226@compuserve.com> Because code marked unsafe for kprobes jumps directly to entry.S::error_code, that must be marked unsafe as well. The easiest way to do that is to move the page fault entry point to just before error_code and let it inherit the same section. Also moved all the ".previous" asm directives for kprobes sections to column 1 and removed ".text" from them. Signed-off-by: Chuck Ebbert <76306.1226@compuserve.com> Signed-off-by: Andi Kleen <ak@suse.de>
Diffstat (limited to 'include/linux/linkage.h')
-rw-r--r--include/linux/linkage.h6
1 files changed, 5 insertions, 1 deletions
diff --git a/include/linux/linkage.h b/include/linux/linkage.h
index 932021f872d5..6c9873f88287 100644
--- a/include/linux/linkage.h
+++ b/include/linux/linkage.h
@@ -35,9 +35,13 @@
35#endif 35#endif
36 36
37#define KPROBE_ENTRY(name) \ 37#define KPROBE_ENTRY(name) \
38 .section .kprobes.text, "ax"; \ 38 .pushsection .kprobes.text, "ax"; \
39 ENTRY(name) 39 ENTRY(name)
40 40
41#define KPROBE_END(name) \
42 END(name); \
43 .popsection
44
41#ifndef END 45#ifndef END
42#define END(name) \ 46#define END(name) \
43 .size name, .-name 47 .size name, .-name