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| author | Ralf Baechle <ralf@linux-mips.org> | 2010-10-29 18:08:24 (GMT) |
|---|---|---|
| committer | Ralf Baechle <ralf@linux-mips.org> | 2010-10-29 18:08:24 (GMT) |
| commit | 7837314d141c661c70bc13c5050694413ecfe14a (patch) | |
| tree | de137b1d2945d2490bc1dcdf6d76eac6006f7ab0 /arch/mips/Makefile | |
| parent | 18cb657ca1bafe635f368346a1676fb04c512edf (diff) | |
| download | linux-7837314d141c661c70bc13c5050694413ecfe14a.tar.xz | |
MIPS: Get rid of branches to .subsections.
It was a nice optimization - on paper at least. In practice it results in
branches that may exceed the maximum legal range for a branch. We can
fight that problem with -ffunction-sections but -ffunction-sections again
is incompatible with -pg used by the function tracer.
By rewriting the loop around all simple LL/SC blocks to C we reduce the
amount of inline assembler and at the same time allow GCC to often fill
the branch delay slots with something sensible or whatever else clever
optimization it may have up in its sleeve.
With this optimization gone we also no longer need -ffunction-sections,
so drop it.
This optimization was originally introduced in 2.6.21, commit
5999eca25c1fd4b9b9aca7833b04d10fe4bc877d (linux-mips.org) rsp.
f65e4fa8e0c6022ad58dc88d1b11b12589ed7f9f (kernel.org).
Original fix for the issues which caused me to pull this optimization by
Paul Gortmaker <paul.gortmaker@windriver.com>.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Diffstat (limited to 'arch/mips/Makefile')
| -rw-r--r-- | arch/mips/Makefile | 3 |
1 files changed, 0 insertions, 3 deletions
diff --git a/arch/mips/Makefile b/arch/mips/Makefile index f4a4b66..1a81240 100644 --- a/arch/mips/Makefile +++ b/arch/mips/Makefile @@ -48,9 +48,6 @@ ifneq ($(SUBARCH),$(ARCH)) endif endif -ifndef CONFIG_FUNCTION_TRACER -cflags-y := -ffunction-sections -endif ifdef CONFIG_FUNCTION_GRAPH_TRACER ifndef KBUILD_MCOUNT_RA_ADDRESS ifeq ($(call cc-option-yn,-mmcount-ra-address), y) |