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arm64: lse: Pass -fomit-frame-pointer to out-of-line ll/sc atomics
authorWill Deacon <will.deacon@arm.com>
Fri, 9 Feb 2018 13:19:47 +0000 (13:19 +0000)
committerWill Deacon <will.deacon@arm.com>
Tue, 6 Mar 2018 18:52:32 +0000 (18:52 +0000)
In cases where x30 is used as a temporary in the out-of-line ll/sc atomics
(e.g. atomic_fetch_add), the compiler tends to put out a full stackframe,
which included pointing the x29 at the new frame.

Since these things aren't traceable anyway, we can pass -fomit-frame-pointer
to reduce the work when spilling. Since this is incompatible with -pg, we
also remove that from the CFLAGS for this file.

Signed-off-by: Will Deacon <will.deacon@arm.com>
arch/arm64/lib/Makefile

index 4e696f9..0ead8a1 100644 (file)
@@ -17,6 +17,7 @@ CFLAGS_atomic_ll_sc.o := -fcall-used-x0 -ffixed-x1 -ffixed-x2         \
                   -ffixed-x7 -fcall-saved-x8 -fcall-saved-x9           \
                   -fcall-saved-x10 -fcall-saved-x11 -fcall-saved-x12   \
                   -fcall-saved-x13 -fcall-saved-x14 -fcall-saved-x15   \
-                  -fcall-saved-x18
+                  -fcall-saved-x18 -fomit-frame-pointer
+CFLAGS_REMOVE_atomic_ll_sc.o := -pg
 
 lib-$(CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE) += uaccess_flushcache.o