• Masahiro Yamada's avatar
    kbuild: Disable extra debugging info in .s output · 1e88e415
    Masahiro Yamada authored
    Modern gcc adds view assignments, reset assertion checking in .loc
    directives and a couple more additional debug markers, which clutters
    the asm output unnecessarily:
    
    For example:
    
      bsp_resume:
      .LFB3466:
              .loc 1 1868 1 is_stmt 1 view -0
              .cfi_startproc
              .loc 1 1869 2 view .LVU73
      # arch/x86/kernel/cpu/common.c:1869:    if (this_cpu->c_bsp_resume)
              .loc 1 1869 14 is_stmt 0 view .LVU74
              movq    this_cpu(%rip), %rax    # this_cpu, this_cpu
              movq    64(%rax), %rax  # this_cpu.94_1->c_bsp_resume, _2
      # arch/x86/kernel/cpu/common.c:1869:    if (this_cpu->c_bsp_resume)
              .loc 1 1869 5 view .LVU75
              testq   %rax, %rax      # _2
              je      .L8     #,
              .loc 1 1870 3 is_stmt 1 view .LVU76
              movq    $boot_cpu_data, %rdi    #,
              jmp     __x86_indirect_thunk_rax
    
    or
            .loc 2 57 9 view .LVU478
            .loc 2 57 9 view .LVU479
            .loc 2 57 9 view .LVU480
            .loc 2 57 9 view .LVU481
      .LBB1385:
      .LBB1383:
      .LBB1379:
      .LBB1377:
      .LBB1375:
            .loc 2 57 9 view .LVU482
            .loc 2 57 9 view .LVU483
            movl	%edi, %edx	# cpu, cpu
      .LVL87:
            .loc 2 57 9 is_stmt 0 view .LVU484
    
    That MOV in there is drowned in debugging information and latter makes
    it hard to follow the asm. And that DWARF info is not really needed for
    asm output staring.
    
    Disable the debug information generation which clutters the asm output
    unnecessarily:
    
      bsp_resume:
      # arch/x86/kernel/cpu/common.c:1869:    if (this_cpu->c_bsp_resume)
              movq    this_cpu(%rip), %rax    # this_cpu, this_cpu
              movq    64(%rax), %rax  # this_cpu.94_1->c_bsp_resume, _2
      # arch/x86/kernel/cpu/common.c:1869:    if (this_cpu->c_bsp_resume)
              testq   %rax, %rax      # _2
              je      .L8     #,
      # arch/x86/kernel/cpu/common.c:1870:            this_cpu->c_bsp_resume(&boot_cpu_data);
              movq    $boot_cpu_data, %rdi    #,
              jmp     __x86_indirect_thunk_rax
      .L8:
      # arch/x86/kernel/cpu/common.c:1871: }
              rep ret
              .size   bsp_resume, .-bsp_resume
    
      [ bp: write commit message. ]
    Signed-off-by: default avatarMasahiro Yamada <yamada.masahiro@socionext.com>
    Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
    1e88e415
Makefile.build 17.2 KB