Techwizz/kernel-fxtec-pro1x
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powerpc: Enable jump label support

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When looking through some instruction traces I noticed our tracepoint
checks were inline. It turns out we don't have CONFIG_JUMP_LABEL
enabled.

By enabling CONFIG_JUMP_LABEL we replace a load/compare/branch with
a nop at every tracepoint call. For example in do_IRQ:

CONFIG_JUMP_LABEL disabled:
        stdx 3,11,9
        lwz 0,8(29)
        cmpwi 7,0,0
        bne- 7,.L124
        bl .irq_enter

CONFIG_JUMP_LABEL enabled:
        stdx 3,11,9
        nop
        bl .irq_enter

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
This commit is contained in:
Anton Blanchard 2012-05-22 17:58:41 +00:00 • committed by Benjamin Herrenschmidt
parent 16aaaff684
commit 641bd53a61
2 changed files with 2 additions and 0 deletions

1
arch/powerpc/configs/ppc64_defconfig
View file

@ -16,6 +16,7 @@ CONFIG_BLK_DEV_INITRD=y
CONFIG_PROFILING=y
CONFIG_OPROFILE=y
CONFIG_KPROBES=y
CONFIG_JUMP_LABEL=y
CONFIG_MODULES=y
CONFIG_MODULE_UNLOAD=y
CONFIG_MODVERSIONS=y

1
arch/powerpc/configs/pseries_defconfig
View file

@ -24,6 +24,7 @@ CONFIG_BLK_DEV_INITRD=y
CONFIG_PROFILING=y
CONFIG_OPROFILE=y
CONFIG_KPROBES=y
CONFIG_JUMP_LABEL=y
CONFIG_MODULES=y
CONFIG_MODULE_UNLOAD=y
CONFIG_MODVERSIONS=y