• Artem Bityutskiy's avatar
    kbuild: move KALLSYMS_EXTRA_PASS from Kconfig to Makefile · 1e2795a1
    Artem Bityutskiy authored
    At the moment we have the CONFIG_KALLSYMS_EXTRA_PASS Kconfig switch,
    which users can enable or disable while configuring the kernel. This
    option is then used by 'make' to determine whether an extra kallsyms
    pass is needed or not.
    
    However, this approach is not nice and confusing, and this patch moves
    CONFIG_KALLSYMS_EXTRA_PASS from Kconfig to Makefile instead. The
    rationale is below.
    
    1. CONFIG_KALLSYMS_EXTRA_PASS is really about the build time, not
       run-time. There is no real need for it to be in Kconfig. It is
       just an additional work-around which should be used only in rare
       cases, when someone breaks kallsyms, so Kbuild/Makefile is much
       better place for this option.
    2. Grepping CONFIG_KALLSYMS_EXTRA_PASS shows that many defconfigs have
       it enabled, probably not because they try to work-around a kallsyms
       bug, but just because the Kconfig help text is confusing and does
       not really make it clear that this option should not be used unless
       except when kallsyms is broken.
    3. And since many people have CONFIG_KALLSYMS_EXTRA_PASS enabled in
       their Kconfig, we do might fail to notice kallsyms bugs in time. E.g.,
       many testers use "make allyesconfig" to test builds, which will enable
       CONFIG_KALLSYMS_EXTRA_PASS and kallsyms breakage will not be noticed.
    
    To address that, this patch:
    
    1. Kills CONFIG_KALLSYMS_EXTRA_PASS
    2. Changes Makefile so that people can use "make KALLSYMS_EXTRA_PASS=1"
       to enable the extra pass if needed. Additionally, they may define
       KALLSYMS_EXTRA_PASS as an environment variable.
    3. By default KALLSYMS_EXTRA_PASS is disabled and if kallsyms has issues,
       "make" should print a warning and suggest using KALLSYMS_EXTRA_PASS
    Signed-off-by: default avatarArtem Bityutskiy <Artem.Bityutskiy@nokia.com>
    [mmarek: Removed make help text, is not necessary]
    Signed-off-by: default avatarMichal Marek <mmarek@suse.cz>
    1e2795a1
Makefile 51.2 KB