[U-Boot-Users] [PATCH] notes on cpu/mips/config.mk

[U-Boot-Users] [PATCH] notes on cpu/mips/config.mk

[Rodolfo Giometti]

Hello,

I have a mips based board and during u-boot support developing I
notice that in file ?cpu/mips/config.mk?:

* should be replaced this line 

   -mips-linux-as --version|grep "GNU assembler"|awk '{print $$3}'|awk -F . '{print $$2}')
   +$(AS) --version|grep "GNU assembler"|awk '{print $$3}'|awk -F . '{print $$2}')

to avoid errors for user not having ?mips-linux-as? (I have
mipsel-linux-as).

* should be used ?allow_branch_to_undefined? or
?mips_allow_branch_to_undefined? as GAS option? My toolchain use
?allow_branch_to_undefined?...

* Variable MIPSFLAGS is ambiguous, I suggest using MIPSCFLAGS and/or
MIPSLDFLAGS.

In the end I suggest the following patch for file cpu/mips/config.mk:

Index: cpu/mips/config.mk
===================================================================
RCS file: /home/develop/cvs_private/uboot-mips-exadron/cpu/mips/config.mk,v
retrieving revision 1.1.1.1
diff -u -r1.1.1.1 config.mk
--- a/cpu/mips/config.mk        16 Sep 2005 12:14:19 -0000      1.1.1.1
+++ b/cpu/mips/config.mk        16 Sep 2005 14:19:29 -0000
@@ -21,20 +21,22 @@
 # MA 02111-1307 USA
 #
 v=$(shell \
-mips-linux-as --version|grep "GNU assembler"|awk '{print $$3}'|awk -F . '{print $$2}')
-MIPSFLAGS=$(shell \
+$(AS) --version|grep "GNU assembler"|awk '{print $$3}'|awk -F . '{print $$2}')
+MIPSCFLAGS=$(shell \
 if [ "$v" -lt "14" ]; then \
        echo "-mcpu=4kc"; \
 else \
-       echo "-march=4kc -mtune=4kc -Wa,-mips_allow_branch_to_undefined"; \
+       echo "-march=4kc -mtune=4kc -Wa,-allow_branch_to_undefined"; \
 fi)
 
 ifneq (,$(findstring 4KCle,$(CROSS_COMPILE)))
-ENDIANNESS = -EL
-else
-ENDIANNESS = -EB
+MIPSCFLAGS += -EL
+endif
+ifneq (,$(findstring mipsel,$(CROSS_COMPILE)))
+MIPSLDFLAGS += -EL
 endif
 
-MIPSFLAGS += $(ENDIANNESS) -mabicalls
+MIPSCFLAGS += -mabicalls
 
-PLATFORM_CPPFLAGS += $(MIPSFLAGS)
+PLATFORM_CPPFLAGS += $(MIPSCFLAGS)
+PLATFORM_LDFLAGS += $(MIPSLDFLAGS)

Ciao,

Rodolfo

-- 

GNU/Linux Solutions                  e-mail:    giometti at linux.it
Linux Device Driver                             giometti at enneenne.com
Embedded Systems                     home page: giometti.enneenne.com
UNIX programming                     phone:     +39 349 2432127

[U-Boot-Users] [PATCH] notes on cpu/mips/config.mk

[Matej Kupljen]

Hi

> I have a mips based board and during u-boot support developing I
> notice that in file ?cpu/mips/config.mk?:

Please, take a look at:
http://sourceforge.net/mailarchive/message.php?msg_id=12736269

where we have already discussed about this (A new version of config.mk
is also attached.)

> * should be used ?allow_branch_to_undefined? or
> ?mips_allow_branch_to_undefined? as GAS option? My toolchain use
> ?allow_branch_to_undefined?...

Mine too.

BR,
Matej

[U-Boot-Users] [PATCH] notes on cpu/mips/config.mk

[Chuck Meade]

Hi Rodolfo,

> Hello,
>
> I have a mips based board and during u-boot support developing I
> notice that in file ?cpu/mips/config.mk?:
>
> * should be replaced this line
>
>    -mips-linux-as --version|grep "GNU assembler"|awk '{print $$3}'|awk -F . '{print $$2}')
>    +$(AS) --version|grep "GNU assembler"|awk '{print $$3}'|awk -F . '{print $$2}')
>
> to avoid errors for user not having ?mips-linux-as? (I have
> mipsel-linux-as).

OK

...
> In the end I suggest the following patch for file cpu/mips/config.mk:
>
> Index: cpu/mips/config.mk
> ===================================================================
> RCS file: /home/develop/cvs_private/uboot-mips-exadron/cpu/mips/config.mk,v
> retrieving revision 1.1.1.1
> diff -u -r1.1.1.1 config.mk
> --- a/cpu/mips/config.mk        16 Sep 2005 12:14:19 -0000      1.1.1.1
> +++ b/cpu/mips/config.mk        16 Sep 2005 14:19:29 -0000
> @@ -21,20 +21,22 @@
>  # MA 02111-1307 USA
>  #
>  v=$(shell \
> -mips-linux-as --version|grep "GNU assembler"|awk '{print $$3}'|awk -F . '{print $$2}')
> -MIPSFLAGS=$(shell \
> +$(AS) --version|grep "GNU assembler"|awk '{print $$3}'|awk -F . '{print $$2}')
> +MIPSCFLAGS=$(shell \
>  if [ "$v" -lt "14" ]; then \
>         echo "-mcpu=4kc"; \
>  else \
> -       echo "-march=4kc -mtune=4kc -Wa,-mips_allow_branch_to_undefined"; \
> +       echo "-march=4kc -mtune=4kc -Wa,-allow_branch_to_undefined"; \
>  fi)
>
>  ifneq (,$(findstring 4KCle,$(CROSS_COMPILE)))
> -ENDIANNESS = -EL
> -else
> -ENDIANNESS = -EB
> +MIPSCFLAGS += -EL
> +endif
> +ifneq (,$(findstring mipsel,$(CROSS_COMPILE)))
> +MIPSLDFLAGS += -EL
>  endif
>
> -MIPSFLAGS += $(ENDIANNESS) -mabicalls
> +MIPSCFLAGS += -mabicalls
>
> -PLATFORM_CPPFLAGS += $(MIPSFLAGS)
> +PLATFORM_CPPFLAGS += $(MIPSCFLAGS)
> +PLATFORM_LDFLAGS += $(MIPSLDFLAGS)

You removed any logical path by which "-EB" would be added to the flags.
Your addition of the new flag variables is fine if it works, but it should
not break the big endian code.  Why don't you rework your patch to not break
big endian support?

Chuck Meade
The PTR Group

[U-Boot-Users] [PATCH] notes on cpu/mips/config.mk

[Rodolfo Giometti]

On Thu, Sep 29, 2005 at 10:56:33AM -0400, Chuck Meade wrote:
> You removed any logical path by which "-EB" would be added to the flags.
> Your addition of the new flag variables is fine if it works, but it should
> not break the big endian code.  Why don't you rework your patch to not break
> big endian support?

I don't think I'm breaking big endian support with my patch since if
you have the ld command:

   OUTPUT_FORMAT("elf32-tradbigmips", "elf32-tradbigmips", "elf32-tradlittlemips")

you say to the linker that your default endian is "big", please see:

   info -f /usr/local/mipsel/info/ld.info -n "Format Commands"

So if you do not specify "-EB" nor "-EL" the linker will use default
(big endian in the above example).

The following patch also fixes examples compilations:

Index: examples/mips.lds
===================================================================
RCS file: /home/develop/cvs_private/uboot-mips-exadron/examples/mips.lds,v
retrieving revision 1.1.1.1
retrieving revision 1.2
diff -u -r1.1.1.1 -r1.2
--- a/examples/mips.lds 16 Sep 2005 12:14:21 -0000      1.1.1.1
+++ b/examples/mips.lds 16 Sep 2005 15:05:08 -0000      1.2
@@ -24,7 +24,7 @@
 /*
 OUTPUT_FORMAT("elf32-bigmips", "elf32-bigmips", "elf32-bigmips")
 */
-OUTPUT_FORMAT("elf32-tradbigmips", "elf32-tradbigmips", "elf32-tradbigmips")
+OUTPUT_FORMAT("elf32-tradbigmips", "elf32-tradbigmips", "elf32-tradlittlemips")
 OUTPUT_ARCH(mips)
 SECTIONS
 {

Ciao,

Rodolfo

-- 

GNU/Linux Solutions                  e-mail:    giometti at linux.it
Linux Device Driver                             giometti at enneenne.com
Embedded Systems                     home page: giometti.enneenne.com
UNIX programming                     phone:     +39 349 2432127
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[U-Boot-Users] [PATCH] notes on cpu/mips/config.mk

[Chuck Meade]

Hi Rodolfo,

> I don't think I'm breaking big endian support with my patch since if
> you have the ld command:
> 
>    OUTPUT_FORMAT("elf32-tradbigmips", "elf32-tradbigmips", "elf32-tradlittlemips")
> 
> you say to the linker that your default endian is "big", please see:
> 
>    info -f /usr/local/mipsel/info/ld.info -n "Format Commands"
> 
> So if you do not specify "-EB" nor "-EL" the linker will use default
> (big endian in the above example).

Your patch removes ENDIANNESS from MIPSFLAGS.  MIPSFLAGS affects more than just
the linker.  Your patch removes the -EB flag being sent to all tools that have
MIPSFLAGS, including the compiler.  Your patch also changes the use of MIPSFLAGS
itself, so this may be hard for you to see.

Look at the file after you have applied your patch, and you will see that there
is now absolutely no way that PLATFORM_CPPFLAGS would *ever* have "-EB" appended
to it.  That is what you have removed.

Chuck Meade
The PTR Group

[U-Boot-Users] [PATCH] notes on cpu/mips/config.mk

[Rodolfo Giometti]

On Thu, Sep 29, 2005 at 12:26:33PM -0400, Chuck Meade wrote:
> Your patch removes ENDIANNESS from MIPSFLAGS.  MIPSFLAGS affects more than just
> the linker.  Your patch removes the -EB flag being sent to all tools that have
> MIPSFLAGS, including the compiler.  Your patch also changes the use of MIPSFLAGS
> itself, so this may be hard for you to see.

Mmm... I see what you mean. Option ?-EB? is used also by the
compiler... I thought it was a linker option only.

> Look at the file after you have applied your patch, and you will see that there
> is now absolutely no way that PLATFORM_CPPFLAGS would *ever* have "-EB" appended
> to it.  That is what you have removed.

Ok, I'll fix better the code in my next patch since I'm working on
removing ?-mips_allow_branch_to_undefined? option from gas.

Thanks,

Rodolfo

-- 

GNU/Linux Solutions                  e-mail:    giometti at linux.it
Linux Device Driver                             giometti at enneenne.com
Embedded Systems                     home page: giometti.enneenne.com
UNIX programming                     phone:     +39 349 2432127
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