diff options
| author | Ard Biesheuvel <ard.biesheuvel@linaro.org> | 2018-09-18 23:51:41 -0700 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2018-09-27 17:56:48 +0200 |
| commit | b34006c4258c9c86597b6b7123d6a9a3513d6cd7 (patch) | |
| tree | a853b8946da55ea47b86f862ae0a80fd5f098565 /tools/objtool | |
| parent | 9fc0f798ab8a6c042d811e45086260eb59be45c1 (diff) | |
x86/jump_table: Use relative references
Similar to the arm64 case, 64-bit x86 can benefit from using relative
references rather than absolute ones when emitting struct jump_entry
instances. Not only does this reduce the memory footprint of the entries
themselves by 33%, it also removes the need for carrying relocation
metadata on relocatable builds (i.e., for KASLR) which saves a fair
chunk of .init space as well (although the savings are not as dramatic
as on arm64)
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-s390@vger.kernel.org
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Jessica Yu <jeyu@kernel.org>
Link: https://lkml.kernel.org/r/20180919065144.25010-7-ard.biesheuvel@linaro.org
Diffstat (limited to 'tools/objtool')
| -rw-r--r-- | tools/objtool/special.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/tools/objtool/special.c b/tools/objtool/special.c index 84f001d52322..50af4e1274b3 100644 --- a/tools/objtool/special.c +++ b/tools/objtool/special.c @@ -30,9 +30,9 @@ #define EX_ORIG_OFFSET 0 #define EX_NEW_OFFSET 4 -#define JUMP_ENTRY_SIZE 24 +#define JUMP_ENTRY_SIZE 16 #define JUMP_ORIG_OFFSET 0 -#define JUMP_NEW_OFFSET 8 +#define JUMP_NEW_OFFSET 4 #define ALT_ENTRY_SIZE 13 #define ALT_ORIG_OFFSET 0 |