Re: [PATCH v2] X86: Makefile: Replace -pg with CC_FLAGS_FTRACE

[Josh Poimboeuf]

Adding Steven Rostedt (ftrace maintainer).

On Fri, Apr 16, 2021 at 01:39:28PM +0800, zhaoxiao wrote:
> In preparation for x86 supporting ftrace built on other compiler
> options, let's have the x86 Makefiles remove the $(CC_FLAGS_FTRACE)
> flags, whatever these may be, rather than assuming '-pg'.
> 
> There should be no functional change as a result of this patch.
> 
> Signed-off-by: zhaoxiao <zhaoxiao@xxxxxxxxxxxxx>
> ---
> v2: add the same change for the other Makefile in arch/x86 directory.
>  arch/x86/entry/vdso/Makefile |  8 ++++----
>  arch/x86/kernel/Makefile     | 16 ++++++++--------
>  arch/x86/kernel/cpu/Makefile |  4 ++--
>  arch/x86/lib/Makefile        |  2 +-
>  arch/x86/mm/Makefile         |  4 ++--
>  arch/x86/xen/Makefile        |  6 +++---
>  6 files changed, 20 insertions(+), 20 deletions(-)
> 
> diff --git a/arch/x86/entry/vdso/Makefile b/arch/x86/entry/vdso/Makefile
> index 05c4abc2fdfd..c5bd91bf9f93 100644
> --- a/arch/x86/entry/vdso/Makefile
> +++ b/arch/x86/entry/vdso/Makefile
> @@ -96,10 +96,10 @@ $(vobjs): KBUILD_CFLAGS := $(filter-out $(CC_FLAGS_LTO) $(GCC_PLUGINS_CFLAGS) $(
>  #
>  # vDSO code runs in userspace and -pg doesn't help with profiling anyway.
>  #
> -CFLAGS_REMOVE_vclock_gettime.o = -pg
> -CFLAGS_REMOVE_vdso32/vclock_gettime.o = -pg
> -CFLAGS_REMOVE_vgetcpu.o = -pg
> -CFLAGS_REMOVE_vsgx.o = -pg
> +CFLAGS_REMOVE_vclock_gettime.o = $(CC_FLAGS_FTRACE)
> +CFLAGS_REMOVE_vdso32/vclock_gettime.o = $(CC_FLAGS_FTRACE)
> +CFLAGS_REMOVE_vgetcpu.o = $(CC_FLAGS_FTRACE)
> +CFLAGS_REMOVE_vsgx.o = $(CC_FLAGS_FTRACE)
>  
>  #
>  # X32 processes use x32 vDSO to access 64bit kernel data.
> diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
> index 2ddf08351f0b..2811fc6a17ba 100644
> --- a/arch/x86/kernel/Makefile
> +++ b/arch/x86/kernel/Makefile
> @@ -13,14 +13,14 @@ CPPFLAGS_vmlinux.lds += -U$(UTS_MACHINE)
>  
>  ifdef CONFIG_FUNCTION_TRACER
>  # Do not profile debug and lowlevel utilities
> -CFLAGS_REMOVE_tsc.o = -pg
> -CFLAGS_REMOVE_paravirt-spinlocks.o = -pg
> -CFLAGS_REMOVE_pvclock.o = -pg
> -CFLAGS_REMOVE_kvmclock.o = -pg
> -CFLAGS_REMOVE_ftrace.o = -pg
> -CFLAGS_REMOVE_early_printk.o = -pg
> -CFLAGS_REMOVE_head64.o = -pg
> -CFLAGS_REMOVE_sev-es.o = -pg
> +CFLAGS_REMOVE_tsc.o = $(CC_FLAGS_FTRACE)
> +CFLAGS_REMOVE_paravirt-spinlocks.o = $(CC_FLAGS_FTRACE)
> +CFLAGS_REMOVE_pvclock.o = $(CC_FLAGS_FTRACE)
> +CFLAGS_REMOVE_kvmclock.o = $(CC_FLAGS_FTRACE)
> +CFLAGS_REMOVE_ftrace.o = $(CC_FLAGS_FTRACE)
> +CFLAGS_REMOVE_early_printk.o = $(CC_FLAGS_FTRACE)
> +CFLAGS_REMOVE_head64.o = $(CC_FLAGS_FTRACE)
> +CFLAGS_REMOVE_sev-es.o = $(CC_FLAGS_FTRACE)
>  endif
>  
>  KASAN_SANITIZE_head$(BITS).o				:= n
> diff --git a/arch/x86/kernel/cpu/Makefile b/arch/x86/kernel/cpu/Makefile
> index 637b499450d1..4435c6de9145 100644
> --- a/arch/x86/kernel/cpu/Makefile
> +++ b/arch/x86/kernel/cpu/Makefile
> @@ -5,8 +5,8 @@
>  
>  # Don't trace early stages of a secondary CPU boot
>  ifdef CONFIG_FUNCTION_TRACER
> -CFLAGS_REMOVE_common.o = -pg
> -CFLAGS_REMOVE_perf_event.o = -pg
> +CFLAGS_REMOVE_common.o = $(CC_FLAGS_FTRACE)
> +CFLAGS_REMOVE_perf_event.o = $(CC_FLAGS_FTRACE)
>  endif
>  
>  # If these files are instrumented, boot hangs during the first second.
> diff --git a/arch/x86/lib/Makefile b/arch/x86/lib/Makefile
> index bad4dee4f0e4..0aa71b8a5bc1 100644
> --- a/arch/x86/lib/Makefile
> +++ b/arch/x86/lib/Makefile
> @@ -21,7 +21,7 @@ KASAN_SANITIZE_cmdline.o  := n
>  KCSAN_SANITIZE_cmdline.o  := n
>  
>  ifdef CONFIG_FUNCTION_TRACER
> -CFLAGS_REMOVE_cmdline.o = -pg
> +CFLAGS_REMOVE_cmdline.o = $(CC_FLAGS_FTRACE)
>  endif
>  
>  CFLAGS_cmdline.o := -fno-stack-protector -fno-jump-tables
> diff --git a/arch/x86/mm/Makefile b/arch/x86/mm/Makefile
> index 5864219221ca..91883d5a0293 100644
> --- a/arch/x86/mm/Makefile
> +++ b/arch/x86/mm/Makefile
> @@ -12,8 +12,8 @@ KASAN_SANITIZE_mem_encrypt_identity.o	:= n
>  KCSAN_SANITIZE := n
>  
>  ifdef CONFIG_FUNCTION_TRACER
> -CFLAGS_REMOVE_mem_encrypt.o		= -pg
> -CFLAGS_REMOVE_mem_encrypt_identity.o	= -pg
> +CFLAGS_REMOVE_mem_encrypt.o		= $(CC_FLAGS_FTRACE)
> +CFLAGS_REMOVE_mem_encrypt_identity.o	= $(CC_FLAGS_FTRACE)
>  endif
>  
>  obj-y				:=  init.o init_$(BITS).o fault.o ioremap.o extable.o mmap.o \
> diff --git a/arch/x86/xen/Makefile b/arch/x86/xen/Makefile
> index 40b5779fce21..179dfc124c94 100644
> --- a/arch/x86/xen/Makefile
> +++ b/arch/x86/xen/Makefile
> @@ -2,9 +2,9 @@
>  
>  ifdef CONFIG_FUNCTION_TRACER
>  # Do not profile debug and lowlevel utilities
> -CFLAGS_REMOVE_spinlock.o = -pg
> -CFLAGS_REMOVE_time.o = -pg
> -CFLAGS_REMOVE_irq.o = -pg
> +CFLAGS_REMOVE_spinlock.o = $(CC_FLAGS_FTRACE)
> +CFLAGS_REMOVE_time.o = $(CC_FLAGS_FTRACE)
> +CFLAGS_REMOVE_irq.o = $(CC_FLAGS_FTRACE)
>  endif
>  
>  # Make sure early boot has no stackprotector
> -- 
> 2.20.1
> 
> 
> 

-- 
Josh