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kallsyms: fix nonconverging kallsyms table with lld
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ARM randconfig builds with lld sometimes show a build failure
from kallsyms:

  Inconsistent kallsyms data
  Try make KALLSYMS_EXTRA_PASS=1 as a workaround

The problem is the veneers/thunks getting added by the linker extend
the symbol table, which in turn leads to more veneers being needed,
so it may take a few extra iterations to converge.

This bug has been fixed multiple times before, but comes back every time
a new symbol name is used. lld uses a different set of identifiers from
ld.bfd, so the additional ones need to be added as well.

I looked through the sources and found that arm64 and mips define similar
prefixes, so I'm adding those as well, aside from the ones I observed. I'm
not sure about powerpc64, which seems to already be handled through a
section match, but if it comes back, the "__long_branch_" and "__plt_"
prefixes would have to get added as well.

Signed-off-by: Arnd Bergmann <[email protected]>
Signed-off-by: Masahiro Yamada <[email protected]>
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arndb authored and masahir0y committed Feb 5, 2021
1 parent 315da87 commit efe6e30
Showing 1 changed file with 6 additions and 0 deletions.
6 changes: 6 additions & 0 deletions scripts/kallsyms.c
Original file line number Diff line number Diff line change
Expand Up @@ -112,6 +112,12 @@ static bool is_ignored_symbol(const char *name, char type)
"__crc_", /* modversions */
"__efistub_", /* arm64 EFI stub namespace */
"__kvm_nvhe_", /* arm64 non-VHE KVM namespace */
"__AArch64ADRPThunk_", /* arm64 lld */
"__ARMV5PILongThunk_", /* arm lld */
"__ARMV7PILongThunk_",
"__ThumbV7PILongThunk_",
"__LA25Thunk_", /* mips lld */
"__microLA25Thunk_",
NULL
};

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