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From:   Fawad Lateef <fawadlateef@gmail.com>
Date:   Sun, 28 Mar 2021 22:20:50 +0200
Message-ID: <CAGgoGu77PEEAJped5bnw4q8rFeDMebL92YWGDGFfNp_ZAnpJ8Q@mail.gmail.com>
Subject: Compiling kernel-3.4.xxx with gcc-9.x. Need some help.
To:     kernelnewbies <kernelnewbies@nl.linux.org>,
        kernelnewbies <kernelnewbies@kernelnewbies.org>,
        linux-kernel@vger.kernel.org
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Hi

I am using an Olimex A20 SOM with NAND and due to some binary blob for
NAND driver, I am stuck with the sunxi kernel 3.4.xxx version. (Repo
here: https://github.com/linux-sunxi/linux-sunxi)

I am currently using buildroot-2016 and gcc-5.5 for building the
kernel and every other package needed.

Now the requirement is to move to the latest version of gcc-9.x, so
that we can have glibc++ provided by the gcc-9.1 toolchain.

Main problem for moving to later versions of buildroot is the kernel
3.4 which we couldn't to work with gcc-6 a few years ago _but_ now the
gcc-9.1 requirement is mandatory so now have to look into compiling
linux-3.4 with gcc-9.1 or above.

Now I need some help.

-- Is it realistic to expect 3.4 kernel compiling and boot
successfully with gcc-9.1?
-- Secondly, till now I am able to compile until the point when its
going to generate the vmlinuz image, it failed with error at LD stage:
                  arm-none-linux-gnueabihf-ld: no machine record defined

Last few lines from compile log:

---------------------------------------------------------------------------=
----
include/linux/init.h:267:24: note: in expansion of macro =E2=80=98__initcal=
l=E2=80=99
  267 | #define module_init(x) __initcall(x);
      |                        ^~~~~~~~~~
net/sunrpc/auth_gss/auth_gss.c:1721:1: note: in expansion of macro =E2=80=
=98module_init=E2=80=99
 1721 | module_init(init_rpcsec_gss)
      | ^~~~~~~~~~~
In file included from include/linux/kernel.h:20,
                 from include/linux/spinlock.h:55,
                 from include/linux/mmzone.h:7,
                 from include/linux/gfp.h:4,
                 from include/linux/slab.h:12,
                 from net/sunrpc/auth_gss/svcauth_gss.c:40:
include/linux/log2.h:22:1: warning: ignoring attribute =E2=80=98noreturn=E2=
=80=99
because it conflicts with attribute =E2=80=98const=E2=80=99 [-Wattributes]
   22 | int ____ilog2_NaN(void);
      | ^~~
  LD      net/sunrpc/auth_gss/auth_rpcgss.o
  LD      net/sunrpc/auth_gss/built-in.o
  LD      net/sunrpc/built-in.o
  LD      net/built-in.o
  LD      vmlinux.o
  MODPOST vmlinux.o
  GEN     .version
  CHK     include/generated/compile.h
  UPD     include/generated/compile.h
  CC      init/version.o
In file included from include/linux/kernel.h:20,
                 from include/linux/cache.h:4,
                 from include/linux/time.h:7,
                 from include/linux/stat.h:60,
                 from include/linux/module.h:10,
                 from init/version.c:10:
include/linux/log2.h:22:1: warning: ignoring attribute =E2=80=98noreturn=E2=
=80=99
because it conflicts with attribute =E2=80=98const=E2=80=99 [-Wattributes]
   22 | int ____ilog2_NaN(void);
      | ^~~
  LD      init/built-in.o
  LD      .tmp_vmlinux1
arm-none-linux-gnueabihf-ld: no machine record defined
Makefile:875: recipe for target '.tmp_vmlinux1' failed
make: *** [.tmp_vmlinux1] Error 1
---------------------------------------------------------------------------=
----


After some investigation I found that the MACHINE_START macro from
arch/arm/include/asm/mach/arch.h  is optimised by compiler and removed
from the object file during compilation of
"arch/arm/plat-sunxi/core.c" due to the error here:

---------------------------------------------------------------

flateef@flateef-XPS-13-9360:~/src/tmp/linux-custom-venus-gc-9.2$ make
ARCH=3Darm CROSS_COMPILE=3Darm-none-linux-gnueabihf- EXTRAVERSION=3D-custom=
1
uImage LOADADDR=3D"0x40008000" -j4
  CHK     include/linux/version.h
  CHK     include/generated/utsrelease.h
make[1]: 'include/generated/mach-types.h' is up to date.
  CALL    scripts/checksyscalls.sh
  CHK     include/generated/compile.h
  CC      arch/arm/plat-sunxi/core.o
In file included from include/linux/kernel.h:20,
                 from arch/arm/plat-sunxi/core.c:20:
include/linux/log2.h:22:1: warning: ignoring attribute =E2=80=98noreturn=E2=
=80=99
because it conflicts with attribute =E2=80=98const=E2=80=99 [-Wattributes]
   22 | int ____ilog2_NaN(void);
      | ^~~
In file included from include/linux/scatterlist.h:10,
                 from include/linux/dma-mapping.h:9,
                 from arch/arm/plat-sunxi/core.c:24:
arch/arm/plat-sunxi/core.c: In function =E2=80=98sw_irq_unmask=E2=80=99:
arch/arm/plat-sunxi/core.c:287:14: warning: left shift count >=3D width
of type [-Wshift-count-overflow]
  287 |    writel((1 << SW_INT_IRQNO_ENMI), SW_INT_IRQ_PENDING_REG0);
      |              ^~
/home/flateef/src/tmp/linux-custom-venus-gc-9.2/arch/arm/include/asm/io.h:5=
2:88:
note: in definition of macro =E2=80=98__raw_writel=E2=80=99
   52 | #define __raw_writel(v,a) (__chk_io_ptr(a), *(volatile
unsigned int __force   *)(a) =3D (v))
      |
                        ^
include/linux/byteorder/generic.h:87:21: note: in expansion of macro
=E2=80=98__cpu_to_le32=E2=80=99
   87 | #define cpu_to_le32 __cpu_to_le32
      |                     ^~~~~~~~~~~~~
/home/flateef/src/tmp/linux-custom-venus-gc-9.2/arch/arm/include/asm/io.h:2=
44:36:
note: in expansion of macro =E2=80=98writel_relaxed=E2=80=99
  244 | #define writel(v,c)  ({ __iowmb(); writel_relaxed(v,c); })
      |                                    ^~~~~~~~~~~~~~
arch/arm/plat-sunxi/core.c:287:4: note: in expansion of macro =E2=80=98writ=
el=E2=80=99
  287 |    writel((1 << SW_INT_IRQNO_ENMI), SW_INT_IRQ_PENDING_REG0);
      |    ^~~~~~
In file included from arch/arm/plat-sunxi/core.c:53:
At top level:
/home/flateef/src/tmp/linux-custom-venus-gc-9.2/arch/arm/include/asm/mach/a=
rch.h:69:34:
warning: =E2=80=98__mach_desc_SUN7I=E2=80=99 defined but not used
[-Wunused-const-variable=3D]
   69 | static const struct machine_desc __mach_desc_##_type  \
      |                                  ^~~~~~~~~~~~
arch/arm/plat-sunxi/core.c:424:1: note: in expansion of macro =E2=80=98MACH=
INE_START=E2=80=99
  424 | MACHINE_START(SUN7I, "sun7i")
      | ^~~~~~~~~~~~~
/home/flateef/src/tmp/linux-custom-venus-gc-9.2/arch/arm/include/asm/mach/a=
rch.h:69:34:
warning: =E2=80=98__mach_desc_SUN5I=E2=80=99 defined but not used
[-Wunused-const-variable=3D]
   69 | static const struct machine_desc __mach_desc_##_type  \
      |                                  ^~~~~~~~~~~~
arch/arm/plat-sunxi/core.c:410:1: note: in expansion of macro =E2=80=98MACH=
INE_START=E2=80=99
  410 | MACHINE_START(SUN5I, "sun5i")
      | ^~~~~~~~~~~~~
/home/flateef/src/tmp/linux-custom-venus-gc-9.2/arch/arm/include/asm/mach/a=
rch.h:69:34:
warning: =E2=80=98__mach_desc_SUN4I=E2=80=99 defined but not used
[-Wunused-const-variable=3D]
   69 | static const struct machine_desc __mach_desc_##_type  \
      |                                  ^~~~~~~~~~~~
arch/arm/plat-sunxi/core.c:396:1: note: in expansion of macro =E2=80=98MACH=
INE_START=E2=80=99
  396 | MACHINE_START(SUN4I, "sun4i")
      | ^~~~~~~~~~~~~
  LD      arch/arm/plat-sunxi/built-in.o
  LD      vmlinux.o
  MODPOST vmlinux.o
  GEN     .version
  CHK     include/generated/compile.h
  UPD     include/generated/compile.h
  CC      init/version.o
In file included from include/linux/kernel.h:20,
                 from include/linux/cache.h:4,
                 from include/linux/time.h:7,
                 from include/linux/stat.h:60,
                 from include/linux/module.h:10,
                 from init/version.c:10:
include/linux/log2.h:22:1: warning: ignoring attribute =E2=80=98noreturn=E2=
=80=99
because it conflicts with attribute =E2=80=98const=E2=80=99 [-Wattributes]
   22 | int ____ilog2_NaN(void);
      | ^~~
  LD      init/built-in.o
  LD      .tmp_vmlinux1
arm-none-linux-gnueabihf-ld: no machine record defined
Makefile:875: recipe for target '.tmp_vmlinux1' failed
make: *** [.tmp_vmlinux1] Error 1

---------------------------------------------------------------

I modified the MACHINE_START macro in arch/arm/include/asm/mach/arch.h
and added "__attribute__((used))" so it became:

            static const struct machine_desc __mach_desc_##_type
__attribute__((used))    \

And I managed to get the vmlinux image.

-------------------------------------------------------------


arch/arm/mm/mmu.c:919:1: note: in expansion of macro =E2=80=98early_param=
=E2=80=99
  919 | early_param("vmalloc", early_vmalloc);
      | ^~~~~~~~~~~
include/linux/init.h:241:33: warning: =E2=80=98__setup_noalign_setup=E2=80=
=99 defined
but not used [-Wunused-variable]
  241 |  static struct obs_kernel_param __setup_##unique_id \
      |                                 ^~~~~~~~
include/linux/init.h:247:2: note: in expansion of macro =E2=80=98__setup_pa=
ram=E2=80=99
  247 |  __setup_param(str, fn, fn, 0)
      |  ^~~~~~~~~~~~~
arch/arm/mm/mmu.c:175:1: note: in expansion of macro =E2=80=98__setup=E2=80=
=99
  175 | __setup("noalign", noalign_setup);
      | ^~~~~~~
include/linux/init.h:241:33: warning: =E2=80=98__setup_early_ecc=E2=80=99 d=
efined but
not used [-Wunused-variable]
  241 |  static struct obs_kernel_param __setup_##unique_id \
      |                                 ^~~~~~~~
include/linux/init.h:252:2: note: in expansion of macro =E2=80=98__setup_pa=
ram=E2=80=99
  252 |  __setup_param(str, fn, fn, 1)
      |  ^~~~~~~~~~~~~
arch/arm/mm/mmu.c:165:1: note: in expansion of macro =E2=80=98early_param=
=E2=80=99
  165 | early_param("ecc", early_ecc);
      | ^~~~~~~~~~~
include/linux/init.h:241:33: warning: =E2=80=98__setup_early_nowrite=E2=80=
=99 defined
but not used [-Wunused-variable]
  241 |  static struct obs_kernel_param __setup_##unique_id \
      |                                 ^~~~~~~~
include/linux/init.h:252:2: note: in expansion of macro =E2=80=98__setup_pa=
ram=E2=80=99
  252 |  __setup_param(str, fn, fn, 1)
      |  ^~~~~~~~~~~~~
arch/arm/mm/mmu.c:154:1: note: in expansion of macro =E2=80=98early_param=
=E2=80=99
  154 | early_param("nowb", early_nowrite);
      | ^~~~~~~~~~~
include/linux/init.h:241:33: warning: =E2=80=98__setup_early_nocache=E2=80=
=99 defined
but not used [-Wunused-variable]
  241 |  static struct obs_kernel_param __setup_##unique_id \
      |                                 ^~~~~~~~
include/linux/init.h:252:2: note: in expansion of macro =E2=80=98__setup_pa=
ram=E2=80=99
  252 |  __setup_param(str, fn, fn, 1)
      |  ^~~~~~~~~~~~~
arch/arm/mm/mmu.c:145:1: note: in expansion of macro =E2=80=98early_param=
=E2=80=99
  145 | early_param("nocache", early_nocache);
      | ^~~~~~~~~~~
include/linux/init.h:241:33: warning: =E2=80=98__setup_early_cachepolicy=E2=
=80=99
defined but not used [-Wunused-variable]
  241 |  static struct obs_kernel_param __setup_##unique_id \
      |                                 ^~~~~~~~
include/linux/init.h:252:2: note: in expansion of macro =E2=80=98__setup_pa=
ram=E2=80=99
  252 |  __setup_param(str, fn, fn, 1)
      |  ^~~~~~~~~~~~~
arch/arm/mm/mmu.c:136:1: note: in expansion of macro =E2=80=98early_param=
=E2=80=99
  136 | early_param("cachepolicy", early_cachepolicy);
      | ^~~~~~~~~~~
  AS      arch/arm/kernel/head.o
  LD      arch/arm/kernel/built-in.o
  AS      arch/arm/mm/cache-v7.o
  AS      arch/arm/mm/tlb-v7.o
  AS      arch/arm/mm/proc-v7.o
  LD      arch/arm/mm/built-in.o
  AS      arch/arm/lib/copy_page.o
  AS      arch/arm/lib/csumpartialcopyuser.o
  AR      arch/arm/lib/lib.a
  LD      vmlinux.o
  MODPOST vmlinux.o
  GEN     .version
  CHK     include/generated/compile.h
  UPD     include/generated/compile.h
  CC      init/version.o
In file included from include/linux/kernel.h:20,
                 from include/linux/cache.h:4,
                 from include/linux/time.h:7,
                 from include/linux/stat.h:60,
                 from include/linux/module.h:10,
                 from init/version.c:10:
include/linux/log2.h:22:1: warning: ignoring attribute =E2=80=98noreturn=E2=
=80=99
because it conflicts with attribute =E2=80=98const=E2=80=99 [-Wattributes]
   22 | int ____ilog2_NaN(void);
      | ^~~
  LD      init/built-in.o
  LD      .tmp_vmlinux1
  KSYM    .tmp_kallsyms1.S
  AS      .tmp_kallsyms1.o
  LD      .tmp_vmlinux2
  KSYM    .tmp_kallsyms2.S
  AS      .tmp_kallsyms2.o
  LD      vmlinux
  SYSMAP  System.map
  SYSMAP  .tmp_System.map
  OBJCOPY arch/arm/boot/Image
  Kernel: arch/arm/boot/Image is ready
  AS      arch/arm/boot/compressed/head.o
  XZKERN  arch/arm/boot/compressed/piggy.xzkern
  CC      arch/arm/boot/compressed/misc.o
  CC      arch/arm/boot/compressed/decompress.o
  CC      arch/arm/boot/compressed/string.o
In file included from include/linux/kernel.h:20,
                 from
arch/arm/boot/compressed/../../../../lib/xz/xz_private.h:15,
                 from
arch/arm/boot/compressed/../../../../lib/decompress_unxz.c:145,
                 from arch/arm/boot/compressed/decompress.c:50:
include/linux/log2.h:22:1: warning: ignoring attribute =E2=80=98noreturn=E2=
=80=99
because it conflicts with attribute =E2=80=98const=E2=80=99 [-Wattributes]
   22 | int ____ilog2_NaN(void);
      | ^~~
  SHIPPED arch/arm/boot/compressed/lib1funcs.S
  SHIPPED arch/arm/boot/compressed/ashldi3.S
  AS      arch/arm/boot/compressed/lib1funcs.o
  AS      arch/arm/boot/compressed/ashldi3.o
  AS      arch/arm/boot/compressed/piggy.xzkern.o
  LD      arch/arm/boot/compressed/vmlinux
  OBJCOPY arch/arm/boot/zImage
  Kernel: arch/arm/boot/zImage is ready
  UIMAGE  arch/arm/boot/uImage
Image Name:   Linux-3.4.113-custom1
Created:      Sun Mar 28 20:27:03 2021
Image Type:   ARM Linux Kernel Image (uncompressed)
Data Size:    1869496 Bytes =3D 1825.68 KiB =3D 1.78 MiB
Load Address: 40008000
Entry Point:  40008000
  Image arch/arm/boot/uImage is ready


---------------------------------------------------------------------------=
--


-- I still can't boot the kernel on the platform. I believe its
because there were lots of warning like above (unused const variables
etc) and might have removed some other code/functions OR macros?

So please suggest what I can do for compiling working kernel-3.4 with gcc-9=
.

Thanks in advance,

-- Fawad Lateef