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    x86/purgatory: Fail the build if purgatory.ro has missing symbols · e4160b2e
    Hans de Goede authored
    
    
    Linking purgatory.ro with -r enables "incremental linking"; this means
    no checks for unresolved symbols are done while linking purgatory.ro.
    
    A change to the sha256 code has caused the purgatory in 5.4-rc1 to have
    a missing symbol on memzero_explicit(), yet things still happily build.
    
    Add an extra check for unresolved symbols by calling ld without -r
    before running bin2c to generate kexec-purgatory.c.
    
    This causes a build of 5.4-rc1 with this patch added to fail as it should:
    
        CHK     arch/x86/purgatory/purgatory.ro
      ld: arch/x86/purgatory/purgatory.ro: in function `sha256_transform':
      sha256.c:(.text+0x1c0c): undefined reference to `memzero_explicit'
      make[2]: *** [arch/x86/purgatory/Makefile:72:
          arch/x86/purgatory/kexec-purgatory.c] Error 1
      make[1]: *** [scripts/Makefile.build:509: arch/x86/purgatory] Error 2
      make: *** [Makefile:1650: arch/x86] Error 2
    
    Also remove --no-undefined from LDFLAGS_purgatory.ro as that has no
    effect.
    
    Signed-off-by: default avatarHans de Goede <hdegoede@redhat.com>
    Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
    Link: https://lkml.kernel.org/r/20200317130841.290418-2-hdegoede@redhat.com
    e4160b2e