[PATCH] scripts/Kbuild.include: Fix portability problem of "echo -e"

[PATCH] scripts/Kbuild.include: Fix portability problem of "echo -e"

[Bernhard Walle]

"echo -e" is a GNU extension. When cross-compiling the kernel on a
BSD-like operating system (Mac OS X in my case), this doesn't work.

One could install a GNU version of echo, put that in the $PATH before
the system echo and use "/usr/bin/env echo", but the solution with
printf is simpler.

Since it is no disadvantage on Linux, I hope that gets accepted even if
cross-compiling the Linux kernel on another Unix operating system is
quite a rare use case.

Signed-off-by: Bernhard Walle <bernhard@bwalle.de>
---
 scripts/Kbuild.include |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/scripts/Kbuild.include b/scripts/Kbuild.include
index d897278..6a3ee98 100644
--- a/scripts/Kbuild.include
+++ b/scripts/Kbuild.include
@@ -104,7 +104,7 @@ as-option = $(call try-run,\
 # Usage: cflags-y += $(call as-instr,instr,option1,option2)
 
 as-instr = $(call try-run,\
-	/bin/echo -e "$(1)" | $(CC) $(KBUILD_AFLAGS) -c -xassembler -o "$$TMP" -,$(2),$(3))
+	printf "%b\n" "$(1)" | $(CC) $(KBUILD_AFLAGS) -c -xassembler -o "$$TMP" -,$(2),$(3))
 
 # cc-option
 # Usage: cflags-y += $(call cc-option,-march=winchip-c6,-march=i586)
-- 
1.7.9

Re: [PATCH] scripts/Kbuild.include: Fix portability problem of "echo -e"

[Sam Ravnborg]

On Sun, Feb 26, 2012 at 06:35:18PM +0100, Bernhard Walle wrote:
> "echo -e" is a GNU extension. When cross-compiling the kernel on a
> BSD-like operating system (Mac OS X in my case), this doesn't work.
> 
> One could install a GNU version of echo, put that in the $PATH before
> the system echo and use "/usr/bin/env echo", but the solution with
> printf is simpler.
> 
> Since it is no disadvantage on Linux, I hope that gets accepted even if
> cross-compiling the Linux kernel on another Unix operating system is
> quite a rare use case.
> 
> Signed-off-by: Bernhard Walle <bernhard@bwalle.de>
> ---
>  scripts/Kbuild.include |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)
> 
> diff --git a/scripts/Kbuild.include b/scripts/Kbuild.include
> index d897278..6a3ee98 100644
> --- a/scripts/Kbuild.include
> +++ b/scripts/Kbuild.include
> @@ -104,7 +104,7 @@ as-option = $(call try-run,\
>  # Usage: cflags-y += $(call as-instr,instr,option1,option2)
>  
>  as-instr = $(call try-run,\
> -	/bin/echo -e "$(1)" | $(CC) $(KBUILD_AFLAGS) -c -xassembler -o "$$TMP" -,$(2),$(3))
> +	printf "%b\n" "$(1)" | $(CC) $(KBUILD_AFLAGS) -c -xassembler -o "$$TMP" -,$(2),$(3))
>  
>  # cc-option
>  # Usage: cflags-y += $(call cc-option,-march=winchip-c6,-march=i586)

Roman Zippel removed use of printf in this patch: beda9f3a13bbb22cde92a45f230a02ef2afef6a9

I cannot remember why - but it would be good if you could dig up
why - just so we do not hit an old issue again.

	Sam

Re: [PATCH] scripts/Kbuild.include: Fix portability problem of "echo -e"

[Bernhard Walle]

Am 26.02.12 18:48, schrieb Sam Ravnborg:
>> > --- a/scripts/Kbuild.include
>> > +++ b/scripts/Kbuild.include
>> > @@ -104,7 +104,7 @@ as-option = $(call try-run,\
>> >  # Usage: cflags-y += $(call as-instr,instr,option1,option2)
>> >  
>> >  as-instr = $(call try-run,\
>> > -	/bin/echo -e "$(1)" | $(CC) $(KBUILD_AFLAGS) -c -xassembler -o "$$TMP" -,$(2),$(3))
>> > +	printf "%b\n" "$(1)" | $(CC) $(KBUILD_AFLAGS) -c -xassembler -o "$$TMP" -,$(2),$(3))
>> >  
>> >  # cc-option
>> >  # Usage: cflags-y += $(call cc-option,-march=winchip-c6,-march=i586)
> Roman Zippel removed use of printf in this patch: beda9f3a13bbb22cde92a45f230a02ef2afef6a9
> 
> I cannot remember why - but it would be good if you could dig up
> why - just so we do not hit an old issue again.

Well, he used printf "$(1)", that's different from printf "%b\n" "$(1)"
since format strings inside $(1) would be interpreted.

But maybe Roman can comment on that? Cc'ing him.


Regards,
Bernhard

Re: [PATCH] scripts/Kbuild.include: Fix portability problem of "echo -e"

[Sam Ravnborg]

On Sun, Feb 26, 2012 at 06:51:34PM +0100, Bernhard Walle wrote:
> Am 26.02.12 18:48, schrieb Sam Ravnborg:
> >> > --- a/scripts/Kbuild.include
> >> > +++ b/scripts/Kbuild.include
> >> > @@ -104,7 +104,7 @@ as-option = $(call try-run,\
> >> >  # Usage: cflags-y += $(call as-instr,instr,option1,option2)
> >> >  
> >> >  as-instr = $(call try-run,\
> >> > -	/bin/echo -e "$(1)" | $(CC) $(KBUILD_AFLAGS) -c -xassembler -o "$$TMP" -,$(2),$(3))
> >> > +	printf "%b\n" "$(1)" | $(CC) $(KBUILD_AFLAGS) -c -xassembler -o "$$TMP" -,$(2),$(3))
> >> >  
> >> >  # cc-option
> >> >  # Usage: cflags-y += $(call cc-option,-march=winchip-c6,-march=i586)
> > Roman Zippel removed use of printf in this patch: beda9f3a13bbb22cde92a45f230a02ef2afef6a9
> > 
> > I cannot remember why - but it would be good if you could dig up
> > why - just so we do not hit an old issue again.
> 
> Well, he used printf "$(1)", that's different from printf "%b\n" "$(1)"
> since format strings inside $(1) would be interpreted.
Makes good sense.

> 
> But maybe Roman can comment on that? Cc'ing him.
Would be good to hear from Roman - but he has been MIA for some years now :-(

	Sam

Re: [PATCH] scripts/Kbuild.include: Fix portability problem of "echo -e"

[Bernhard Walle]

Am 26.02.12 22:05, schrieb Sam Ravnborg:
> On Sun, Feb 26, 2012 at 06:51:34PM +0100, Bernhard Walle wrote:
>> Am 26.02.12 18:48, schrieb Sam Ravnborg:
>>>>> --- a/scripts/Kbuild.include
>>>>> +++ b/scripts/Kbuild.include
>>>>> @@ -104,7 +104,7 @@ as-option = $(call try-run,\
>>>>>  # Usage: cflags-y += $(call as-instr,instr,option1,option2)
>>>>>  
>>>>>  as-instr = $(call try-run,\
>>>>> -	/bin/echo -e "$(1)" | $(CC) $(KBUILD_AFLAGS) -c -xassembler -o "$$TMP" -,$(2),$(3))
>>>>> +	printf "%b\n" "$(1)" | $(CC) $(KBUILD_AFLAGS) -c -xassembler -o "$$TMP" -,$(2),$(3))
>>>>>  
>>>>>  # cc-option
>>>>>  # Usage: cflags-y += $(call cc-option,-march=winchip-c6,-march=i586)
>>> Roman Zippel removed use of printf in this patch: beda9f3a13bbb22cde92a45f230a02ef2afef6a9
>>>
>>> I cannot remember why - but it would be good if you could dig up
>>> why - just so we do not hit an old issue again.
>>
>> Well, he used printf "$(1)", that's different from printf "%b\n" "$(1)"
>> since format strings inside $(1) would be interpreted.
> Makes good sense.

Can we merge that for 3.4? Who is responsible, i.e. whose tree?


Regards,
Bernhard

Re: [PATCH] scripts/Kbuild.include: Fix portability problem of "echo -e"

[Michal Marek]

On Mon, Mar 19, 2012 at 06:44:20PM +0100, Bernhard Walle wrote:
> Am 26.02.12 22:05, schrieb Sam Ravnborg:
> > On Sun, Feb 26, 2012 at 06:51:34PM +0100, Bernhard Walle wrote:
> >> Am 26.02.12 18:48, schrieb Sam Ravnborg:
> >>>>> --- a/scripts/Kbuild.include
> >>>>> +++ b/scripts/Kbuild.include
> >>>>> @@ -104,7 +104,7 @@ as-option = $(call try-run,\
> >>>>>  # Usage: cflags-y += $(call as-instr,instr,option1,option2)
> >>>>>  
> >>>>>  as-instr = $(call try-run,\
> >>>>> -	/bin/echo -e "$(1)" | $(CC) $(KBUILD_AFLAGS) -c -xassembler -o "$$TMP" -,$(2),$(3))
> >>>>> +	printf "%b\n" "$(1)" | $(CC) $(KBUILD_AFLAGS) -c -xassembler -o "$$TMP" -,$(2),$(3))
> >>>>>  
> >>>>>  # cc-option
> >>>>>  # Usage: cflags-y += $(call cc-option,-march=winchip-c6,-march=i586)
> >>> Roman Zippel removed use of printf in this patch: beda9f3a13bbb22cde92a45f230a02ef2afef6a9
> >>>
> >>> I cannot remember why - but it would be good if you could dig up
> >>> why - just so we do not hit an old issue again.
> >>
> >> Well, he used printf "$(1)", that's different from printf "%b\n" "$(1)"
> >> since format strings inside $(1) would be interpreted.
> > Makes good sense.
> 
> Can we merge that for 3.4? Who is responsible, i.e. whose tree?

I merged it to kbuild.git#kbuild now.

Michal

Re: [PATCH] scripts/Kbuild.include: Fix portability problem of "echo -e"

[Andreas Bießmann]

On 26.02.12 18:35, Bernhard Walle wrote:
> "echo -e" is a GNU extension. When cross-compiling the kernel on a
> BSD-like operating system (Mac OS X in my case), this doesn't work.
> 
> One could install a GNU version of echo, put that in the $PATH before
> the system echo and use "/usr/bin/env echo", but the solution with
> printf is simpler.
> 
> Since it is no disadvantage on Linux, I hope that gets accepted even if
> cross-compiling the Linux kernel on another Unix operating system is
> quite a rare use case.
> 
> Signed-off-by: Bernhard Walle <bernhard@bwalle.de>

Tested-by: Andreas Bießmann <andreas@biessmann.de>

Without that patch cross-compiling kernel for omap2 devices on BSD-style
hosts is broken.
For x86 targets the impact is not that hard but CFI is omitted even
though it is supported by assembler (in one case this led to a devious
error message pointing to a assembler bug in my cross toolchain).

So please consider applying this patch.