Thread (24 messages) flat view 24 messages, 5 authors, 2016-01-18

Re: [PATCH v4 4/9] ppc64 ftrace_with_regs configuration variables

From: Petr Mladek <pmladek@suse.com>
Date: 2015-12-03 16:20:13
Also in: lkml

On Wed 2015-11-25 17:37:33, Torsten Duwe wrote:
quoted hunk ↗ jump to hunk
  * Makefile:
    - globally use -mprofile-kernel in case it's configured.
  * arch/powerpc/Kconfig / kernel/trace/Kconfig:
    - declare that ppc64le HAVE_MPROFILE_KERNEL and
      HAVE_DYNAMIC_FTRACE_WITH_REGS, and use it.
--- a/arch/powerpc/Makefile
+++ b/arch/powerpc/Makefile
@@ -133,6 +133,13 @@ else
 CFLAGS-$(CONFIG_GENERIC_CPU) += -mcpu=powerpc64
 endif
 
+ifeq ($(CONFIG_PPC64),y)
+ifdef CONFIG_HAVE_MPROFILE_KERNEL
+CC_FLAGS_FTRACE	:= -pg $(call cc-option,-mprofile-kernel)
Do we want to define -pg even when -mprofile-kernel is not supported
by the used gcc, please?
+KBUILD_CPPFLAGS	+= -DCC_USING_MPROFILE_KERNEL
IMHO, we should not define CC_USING_MPROFILE_KERNEL if it is not
supported by the compiler.

I took inspiration from the CC_USING_FENTRY handling in
linux/Makefile. The following code worked for me:

CC_USING_MPROFILE_KERNEL := $(call cc-option, -pg -mprofile-kernel -DCC_USING_MPROFILE_KERNEL)
CC_FLAGS_FTRACE := $(CC_USING_MPROFILE_KERNEL)
KBUILD_CPPFLAGS += $(CC_USING_MPROFILE_KERNEL)

I just do not understand why we need to add the flags also
to KBUILD_CPPFLAGS. It seems that they are duplicated
when compiling kernel/livepatch/core.o. But livepatching
did not work without it. I wonder if you found the culprit.

Best Regards,
Petr
+endif
+endif
+
 CFLAGS-$(CONFIG_CELL_CPU) += $(call cc-option,-mcpu=cell)
 CFLAGS-$(CONFIG_POWER4_CPU) += $(call cc-option,-mcpu=power4)
 CFLAGS-$(CONFIG_POWER5_CPU) += $(call cc-option,-mcpu=power5)
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