Re: [PATCH 2/2] Makefile: Only specify '--prefix=' when building with clang + GNU as

[kernel test robot]

Hi Nathan,

I love your patch! Perhaps something to improve:

[auto build test WARNING on 7a7fd0de4a9804299793e564a555a49c1fc924cb]

url:    https://github.com/0day-ci/linux/commits/Nathan-Chancellor/Makefile-Remove-gcc-toolchain-flag/20210929-112213
base:   7a7fd0de4a9804299793e564a555a49c1fc924cb
config: x86_64-randconfig-a014-20210929 (attached as .config)
compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project dc6e8dfdfe7efecfda318d43a06fae18b40eb498)
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://github.com/0day-ci/linux/commit/74a168f9e88d9edf5aaa8209d2c39e676de2857a
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Nathan-Chancellor/Makefile-Remove-gcc-toolchain-flag/20210929-112213
        git checkout 74a168f9e88d9edf5aaa8209d2c39e676de2857a
        # save the attached .config to linux build tree
        mkdir build_dir
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=x86_64 SHELL=/bin/bash arch/x86/entry/ arch/x86/kernel/ arch/x86/lib/ kernel/

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@xxxxxxxxx>

All warnings (new ones prefixed by >>):

>> arch/x86/entry/entry_64.S:47:1: warning: DWARF2 only supports one section per compilation unit
   .section .entry.text, "ax"
   ^
>> <instantiation>:11:2: warning: DWARF2 only supports one section per compilation unit
    .pushsection .altinstr_replacement,"ax"
    ^
   <instantiation>:1:1: note: while in macro instantiation
   ALTERNATIVE "jmp .Lend_2", "", ( 7*32+11)
   ^
   arch/x86/entry/entry_64.S:93:2: note: while in macro instantiation
    SWITCH_TO_KERNEL_CR3 scratch_reg=%rsp
    ^
   arch/x86/entry/entry_64.S:741:2: warning: DWARF2 only supports one section per compilation unit
    .section .fixup, "ax"
    ^
--
>> arch/x86/entry/entry_64_compat.S:20:2: warning: DWARF2 only supports one section per compilation unit
    .section .entry.text, "ax"
    ^
>> <instantiation>:11:2: warning: DWARF2 only supports one section per compilation unit
    .pushsection .altinstr_replacement,"ax"
    ^
   <instantiation>:1:1: note: while in macro instantiation
   ALTERNATIVE "jmp .Lend_2", "", ( 7*32+11)
   ^
   arch/x86/entry/entry_64_compat.S:55:2: note: while in macro instantiation
    SWITCH_TO_KERNEL_CR3 scratch_reg=%rax
    ^
--
>> arch/x86/kernel/head_64.S:42:2: warning: DWARF2 only supports one section per compilation unit
    .section ".head.text","ax"
    ^
   arch/x86/kernel/head_64.S:352:2: warning: DWARF2 only supports one section per compilation unit
    .section ".init.text","ax"
    ^
--
>> arch/x86/lib/copy_mc_64.S:138:2: warning: DWARF2 only supports one section per compilation unit
    .section .fixup, "ax"
    ^
--
>> <instantiation>:11:2: warning: DWARF2 only supports one section per compilation unit
    .pushsection .altinstr_replacement,"ax"
    ^
   arch/x86/lib/copy_page_64.S:17:2: note: while in macro instantiation
    ALTERNATIVE "jmp copy_page_regs", "", ( 3*32+16)
    ^
--
>> <instantiation>:11:2: warning: DWARF2 only supports one section per compilation unit
    .pushsection .altinstr_replacement,"ax"
    ^
   arch/x86/lib/copy_user_64.S:58:2: note: while in macro instantiation
    ALTERNATIVE "", ".byte 0x0f,0x01,0xcb", ( 9*32+20)
    ^
   <instantiation>:15:2: warning: DWARF2 only supports one section per compilation unit
    .section .fixup,"ax"
    ^
   arch/x86/lib/copy_user_64.S:61:2: note: while in macro instantiation
    ALIGN_DESTINATION
    ^
--
>> <instantiation>:11:2: warning: DWARF2 only supports one section per compilation unit
    .pushsection .altinstr_replacement,"ax"
    ^
   arch/x86/lib/getuser.S:56:2: note: while in macro instantiation
    ALTERNATIVE "", ".byte 0x0f,0x01,0xcb", ( 9*32+20)
    ^
--
>> arch/x86/lib/memcpy_64.S:10:1: warning: DWARF2 only supports one section per compilation unit
   .pushsection .noinstr.text, "ax"
   ^
   <instantiation>:13:2: warning: DWARF2 only supports one section per compilation unit
    .pushsection .altinstr_replacement,"ax"
    ^
   arch/x86/lib/memcpy_64.S:32:2: note: while in macro instantiation
    ALTERNATIVE_2 "jmp memcpy_orig", "", ( 3*32+16), "jmp memcpy_erms", ( 9*32+ 9)
    ^
--
>> <instantiation>:11:2: warning: DWARF2 only supports one section per compilation unit
    .pushsection .altinstr_replacement,"ax"
    ^
   arch/x86/lib/memmove_64.S:42:2: note: while in macro instantiation
    ALTERNATIVE "cmp $0x20, %rdx; jb 1f", "", (18*32+ 4)
    ^
--
>> <instantiation>:11:2: warning: DWARF2 only supports one section per compilation unit
    .pushsection .altinstr_replacement,"ax"
    ^
   arch/x86/lib/putuser.S:51:2: note: while in macro instantiation
    ALTERNATIVE "", ".byte 0x0f,0x01,0xcb", ( 9*32+20)
    ^


vim +47 arch/x86/entry/entry_64.S

6fd166aae78c0a arch/x86/entry/entry_64.S  Peter Zijlstra 2017-12-04  45  
^1da177e4c3f41 arch/x86_64/kernel/entry.S Linus Torvalds 2005-04-16  46  .code64
ea7145477a461e arch/x86/kernel/entry_64.S Jiri Olsa      2011-03-07 @47  .section .entry.text, "ax"
ea7145477a461e arch/x86/kernel/entry_64.S Jiri Olsa      2011-03-07  48  

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0-DAY CI Kernel Test Service, Intel Corporation
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