Remove the RELOC_HIDE() macro from include/linux/compiler-gcc.h.
The GCC specific macro was historically used to workaround very old
compiler bugs (including pre-4.1 ppc64 GCC). These compilers are long
obsolete.
The generic RELOC_HIDE() macro should be used instead.
The removal of the GCC specific macro results in the
following code size reduction:
text data bss dec hex filename
28526453 4823511 737108 34087072 20820a0 vmlinux-old.o
28520945 4823463 737108 34081516 2080aec vmlinux-new.o
./bloat-o-meter vmlinux-old.o vmlinux-new.o
add/remove: 4/14 grow/shrink: 189/674 up/down: 4433/-7865 (-3432)
...
Total: Before=24103512, After=24100080, chg -0.01%
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
---
include/linux/compiler-gcc.h | 25 -------------------------
1 file changed, 25 deletions(-)
diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h
index 5de824a0b3d7..081e658754b9 100644
--- a/include/linux/compiler-gcc.h
+++ b/include/linux/compiler-gcc.h
@@ -10,31 +10,6 @@
+ __GNUC_MINOR__ * 100 \
+ __GNUC_PATCHLEVEL__)
-/*
- * This macro obfuscates arithmetic on a variable address so that gcc
- * shouldn't recognize the original var, and make assumptions about it.
- *
- * This is needed because the C standard makes it undefined to do
- * pointer arithmetic on "objects" outside their boundaries and the
- * gcc optimizers assume this is the case. In particular they
- * assume such arithmetic does not wrap.
- *
- * A miscompilation has been observed because of this on PPC.
- * To work around it we hide the relationship of the pointer and the object
- * using this macro.
- *
- * Versions of the ppc64 compiler before 4.1 had a bug where use of
- * RELOC_HIDE could trash r30. The bug can be worked around by changing
- * the inline assembly constraint from =g to =r, in this particular
- * case either is valid.
- */
-#define RELOC_HIDE(ptr, off) \
-({ \
- unsigned long __ptr; \
- __asm__ ("" : "=r"(__ptr) : "0"(ptr)); \
- (typeof(ptr)) (__ptr + (off)); \
-})
-
#if defined(LATENT_ENTROPY_PLUGIN) && !defined(__CHECKER__)
#define __latent_entropy __attribute__((latent_entropy))
#endif
--
2.52.0