arm64: remove unneeded copy to init_utsname()->machine
diff mbox

Message ID 1505389204-17231-1-git-send-email-yamada.masahiro@socionext.com
State New, archived
Headers show

Commit Message

Masahiro Yamada Sept. 14, 2017, 11:40 a.m. UTC
As you see in init/version.c, init_uts_ns.name.machine is initially
set to UTS_MACHINE.  There is no point to copy the same string.

I dug the git history to figure out why this line is here.  My best
guess is like this:

 - This line has been around here since the initial support of arm64
   by commit 9703d9d7f77c ("arm64: Kernel booting and initialisation").
   If ARCH (=arm64) and UTS_MACHINE (=aarch64) do not match,
   arch/$(ARCH)/Makefile is supposed to override UTS_MACHINE, but the
   initial version of arch/arm64/Makefile missed to do that.  Instead,
   the boot code copied "aarch64" to init_utsname()->machine.

 - Commit 94ed1f2cb5d4 ("arm64: setup: report ELF_PLATFORM as the
   machine for utsname") replaced "aarch64" with ELF_PLATFORM to
   make "uname" to reflect the endianness.

 - ELF_PLATFORM does not help to provide the UTS machine name to rpm
   target, so commit cfa88c79462d ("arm64: Set UTS_MACHINE in the
   Makefile") fixed it.  The commit simply replaced ELF_PLATFORM with
   UTS_MACHINE, but missed the fact the string copy itself is no longer
   needed.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
---

 arch/arm64/kernel/Makefile | 2 --
 arch/arm64/kernel/setup.c  | 2 --
 2 files changed, 4 deletions(-)

Comments

Masahiro Yamada Oct. 11, 2017, 1:03 p.m. UTC | #1
Hi arm64 maintainers,

Could you check this please?


2017-09-14 20:40 GMT+09:00 Masahiro Yamada <yamada.masahiro@socionext.com>:
> As you see in init/version.c, init_uts_ns.name.machine is initially
> set to UTS_MACHINE.  There is no point to copy the same string.
>
> I dug the git history to figure out why this line is here.  My best
> guess is like this:
>
>  - This line has been around here since the initial support of arm64
>    by commit 9703d9d7f77c ("arm64: Kernel booting and initialisation").
>    If ARCH (=arm64) and UTS_MACHINE (=aarch64) do not match,
>    arch/$(ARCH)/Makefile is supposed to override UTS_MACHINE, but the
>    initial version of arch/arm64/Makefile missed to do that.  Instead,
>    the boot code copied "aarch64" to init_utsname()->machine.
>
>  - Commit 94ed1f2cb5d4 ("arm64: setup: report ELF_PLATFORM as the
>    machine for utsname") replaced "aarch64" with ELF_PLATFORM to
>    make "uname" to reflect the endianness.
>
>  - ELF_PLATFORM does not help to provide the UTS machine name to rpm
>    target, so commit cfa88c79462d ("arm64: Set UTS_MACHINE in the
>    Makefile") fixed it.  The commit simply replaced ELF_PLATFORM with
>    UTS_MACHINE, but missed the fact the string copy itself is no longer
>    needed.
>
> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
> ---
>
>  arch/arm64/kernel/Makefile | 2 --
>  arch/arm64/kernel/setup.c  | 2 --
>  2 files changed, 4 deletions(-)
>
> diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile
> index f2b4e81..29764d7 100644
> --- a/arch/arm64/kernel/Makefile
> +++ b/arch/arm64/kernel/Makefile
> @@ -10,8 +10,6 @@ CFLAGS_REMOVE_ftrace.o = -pg
>  CFLAGS_REMOVE_insn.o = -pg
>  CFLAGS_REMOVE_return_address.o = -pg
>
> -CFLAGS_setup.o = -DUTS_MACHINE='"$(UTS_MACHINE)"'
> -
>  # Object file lists.
>  arm64-obj-y            := debug-monitors.o entry.o irq.o fpsimd.o              \
>                            entry-fpsimd.o process.o ptrace.o setup.o signal.o   \
> diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
> index d4b7405..b2fdb59 100644
> --- a/arch/arm64/kernel/setup.c
> +++ b/arch/arm64/kernel/setup.c
> @@ -23,7 +23,6 @@
>  #include <linux/stddef.h>
>  #include <linux/ioport.h>
>  #include <linux/delay.h>
> -#include <linux/utsname.h>
>  #include <linux/initrd.h>
>  #include <linux/console.h>
>  #include <linux/cache.h>
> @@ -246,7 +245,6 @@ void __init setup_arch(char **cmdline_p)
>  {
>         pr_info("Boot CPU: AArch64 Processor [%08x]\n", read_cpuid_id());
>
> -       sprintf(init_utsname()->machine, UTS_MACHINE);
>         init_mm.start_code = (unsigned long) _text;
>         init_mm.end_code   = (unsigned long) _etext;
>         init_mm.end_data   = (unsigned long) _edata;
> --
> 2.7.4
>
Mark Rutland Oct. 11, 2017, 1:13 p.m. UTC | #2
Hi,

On Wed, Oct 11, 2017 at 10:03:28PM +0900, Masahiro Yamada wrote:
> Hi arm64 maintainers,
> 
> Could you check this please?

This patch has been queued [1] in arm64's for-next/core branch [2], and
should be in v4.15.

Thanks,
Mark.

[1] https://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git/commit/?h=for-next/core&id=c2f0b54f10b12620c57f6e31233589b704a00ed5
[2] https://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git/log/?h=for-next/core

> 2017-09-14 20:40 GMT+09:00 Masahiro Yamada <yamada.masahiro@socionext.com>:
> > As you see in init/version.c, init_uts_ns.name.machine is initially
> > set to UTS_MACHINE.  There is no point to copy the same string.
> >
> > I dug the git history to figure out why this line is here.  My best
> > guess is like this:
> >
> >  - This line has been around here since the initial support of arm64
> >    by commit 9703d9d7f77c ("arm64: Kernel booting and initialisation").
> >    If ARCH (=arm64) and UTS_MACHINE (=aarch64) do not match,
> >    arch/$(ARCH)/Makefile is supposed to override UTS_MACHINE, but the
> >    initial version of arch/arm64/Makefile missed to do that.  Instead,
> >    the boot code copied "aarch64" to init_utsname()->machine.
> >
> >  - Commit 94ed1f2cb5d4 ("arm64: setup: report ELF_PLATFORM as the
> >    machine for utsname") replaced "aarch64" with ELF_PLATFORM to
> >    make "uname" to reflect the endianness.
> >
> >  - ELF_PLATFORM does not help to provide the UTS machine name to rpm
> >    target, so commit cfa88c79462d ("arm64: Set UTS_MACHINE in the
> >    Makefile") fixed it.  The commit simply replaced ELF_PLATFORM with
> >    UTS_MACHINE, but missed the fact the string copy itself is no longer
> >    needed.
> >
> > Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
> > ---
> >
> >  arch/arm64/kernel/Makefile | 2 --
> >  arch/arm64/kernel/setup.c  | 2 --
> >  2 files changed, 4 deletions(-)
> >
> > diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile
> > index f2b4e81..29764d7 100644
> > --- a/arch/arm64/kernel/Makefile
> > +++ b/arch/arm64/kernel/Makefile
> > @@ -10,8 +10,6 @@ CFLAGS_REMOVE_ftrace.o = -pg
> >  CFLAGS_REMOVE_insn.o = -pg
> >  CFLAGS_REMOVE_return_address.o = -pg
> >
> > -CFLAGS_setup.o = -DUTS_MACHINE='"$(UTS_MACHINE)"'
> > -
> >  # Object file lists.
> >  arm64-obj-y            := debug-monitors.o entry.o irq.o fpsimd.o              \
> >                            entry-fpsimd.o process.o ptrace.o setup.o signal.o   \
> > diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
> > index d4b7405..b2fdb59 100644
> > --- a/arch/arm64/kernel/setup.c
> > +++ b/arch/arm64/kernel/setup.c
> > @@ -23,7 +23,6 @@
> >  #include <linux/stddef.h>
> >  #include <linux/ioport.h>
> >  #include <linux/delay.h>
> > -#include <linux/utsname.h>
> >  #include <linux/initrd.h>
> >  #include <linux/console.h>
> >  #include <linux/cache.h>
> > @@ -246,7 +245,6 @@ void __init setup_arch(char **cmdline_p)
> >  {
> >         pr_info("Boot CPU: AArch64 Processor [%08x]\n", read_cpuid_id());
> >
> > -       sprintf(init_utsname()->machine, UTS_MACHINE);
> >         init_mm.start_code = (unsigned long) _text;
> >         init_mm.end_code   = (unsigned long) _etext;
> >         init_mm.end_data   = (unsigned long) _edata;
> > --
> > 2.7.4
> >
> 
> 
> 
> -- 
> Best Regards
> Masahiro Yamada

Patch
diff mbox

diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile
index f2b4e81..29764d7 100644
--- a/arch/arm64/kernel/Makefile
+++ b/arch/arm64/kernel/Makefile
@@ -10,8 +10,6 @@  CFLAGS_REMOVE_ftrace.o = -pg
 CFLAGS_REMOVE_insn.o = -pg
 CFLAGS_REMOVE_return_address.o = -pg
 
-CFLAGS_setup.o = -DUTS_MACHINE='"$(UTS_MACHINE)"'
-
 # Object file lists.
 arm64-obj-y		:= debug-monitors.o entry.o irq.o fpsimd.o		\
 			   entry-fpsimd.o process.o ptrace.o setup.o signal.o	\
diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
index d4b7405..b2fdb59 100644
--- a/arch/arm64/kernel/setup.c
+++ b/arch/arm64/kernel/setup.c
@@ -23,7 +23,6 @@ 
 #include <linux/stddef.h>
 #include <linux/ioport.h>
 #include <linux/delay.h>
-#include <linux/utsname.h>
 #include <linux/initrd.h>
 #include <linux/console.h>
 #include <linux/cache.h>
@@ -246,7 +245,6 @@  void __init setup_arch(char **cmdline_p)
 {
 	pr_info("Boot CPU: AArch64 Processor [%08x]\n", read_cpuid_id());
 
-	sprintf(init_utsname()->machine, UTS_MACHINE);
 	init_mm.start_code = (unsigned long) _text;
 	init_mm.end_code   = (unsigned long) _etext;
 	init_mm.end_data   = (unsigned long) _edata;