[PATCH] ppc64: remove -fno-omit-frame-pointer

During some code inspection using gcc 4.0 I noticed a stack frame was being
created for a number of functions that didnt require it.  For example:

c0000000000df944 <._spin_unlock>:
c0000000000df944:       fb e1 ff f0     std     r31,-16(r1)
c0000000000df948:       f8 21 ff c1     stdu    r1,-64(r1)
c0000000000df94c:       7c 3f 0b 78     mr      r31,r1
c0000000000df950:       7c 20 04 ac     lwsync
c0000000000df954:       e8 21 00 00     ld      r1,0(r1)
c0000000000df958:       38 00 00 00     li      r0,0
c0000000000df95c:       90 03 00 00     stw     r0,0(r3)
c0000000000df960:       eb e1 ff f0     ld      r31,-16(r1)
c0000000000df964:       4e 80 00 20     blr

It turns out we are adding -fno-omit-frame-pointer to ppc64 which is
causing the above behaviour.  Removing that flag results in much better
code:

c0000000000d5b30 <._spin_unlock>:
c0000000000d5b30:       7c 20 04 ac     lwsync
c0000000000d5b34:       38 00 00 00     li      r0,0
c0000000000d5b38:       90 03 00 00     stw     r0,0(r3)
c0000000000d5b3c:       4e 80 00 20     blr

We dont require a frame pointer to debug on ppc64, so remove it.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/arch/ppc64/Kconfig b/arch/ppc64/Kconfig
index 15c4a1455caee73829879fec90d7345804a4d4a5..ef1f05e437c4dc9d908076a82a22f5364a471198 100644 (file)
--- a/arch/ppc64/Kconfig
+++ b/arch/ppc64/Kconfig
@@ -40,10 +40,6 @@ config COMPAT
        bool
        default y
 
-config FRAME_POINTER
-       bool
-       default y
-
 # We optimistically allocate largepages from the VM, so make the limit
 # large enough (16MB). This badly named config option is actually
 # max order + 1