Enable building with lld #75
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Could you rebase this and have a look into the CI issues. Unfortunately, the logs have been deleted, so I can't see why RV32 complains about. |
33 tasks
Lost track of this PR, I have now rebased and made a minor change not to fail on GCC versions that don't support |
axel-h
reviewed
Jan 16, 2024
axel-h
reviewed
Jan 16, 2024
Indanz
requested changes
Jan 25, 2024
Indanz
approved these changes
Jan 26, 2024
PT_PHDR is emitted by ld.lld but not ld.bfd. This segment should only exist if the program header *is* part of the program memory image itself (which is not the case in seL4, as it copies the program header in the stack). This is important as muslc’s TLS init is relying on the existence of PT_PHDR to get the base address of the image in memory and from that, it calculates the TLS base for the source ELF. The calculation will be wrong in seL4 as the program header is copied in the stack; thus it may trigger a page fault if the new TLS base is not mapped, or affects the integrity of programs relying on TLS variables (e.g., those with __thread). By setting PT_PHDR's segment to PT_NULL, muslc will skip this search and won't do any relocations for the TLS segment which is part of the loaded ELF image itself, thus getting the correct mapped address. Sponsored by: DARPA. Signed-off-by: Hesham Almatary <hesham.almatary@cl.cam.ac.uk>
unused attribute does not prevent the sections from being garbage-collected during link-time optimisation. This may trigger undefined references errors to [__start|__stop]_test_case symbols that are expected to be emitted by the linker anyway. Adding "retain" attribute makes sure that the section and its associated symbols are kept regardless of linker's garbage collection. Another fix could be adding "nostart-stop-gc" to the linker flags, but since it is only one section (_test_case) where its __start/__stop symbols are references, adding retain to it makes more sense. This additional functionality requires binutils version 2.36 or later. Sponsored by: DARPA. Signed-off-by: Hesham Almatary <hesham.almatary@cl.cam.ac.uk>
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