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Page-align offset before calculating virtual addresses for ELF #626

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andrewjcg
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This mimics what ld.so does by aligning the virtual addresses to the current page size, and fixes:

  • Existing issues with DSOs produced by LLD which, unlike gold or BFD, doesn't align p_vaddr to p_align (the previous overflow prevention wasn't sufficient here).
  • Systems w/ configurable page sizes, where just using p_align isn't enough.

This fixes a bug where we were calculating incorrect address offsets.
// to get real offset for symbol addresses in the file.
let aligned_vaddr =
program_header.p_vaddr - (program_header.p_vaddr % page_size::get() as u64);
let offset = offset - aligned_vaddr;
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Suggested change
let offset = offset - aligned_vaddr;
let offset = offset.saturating_sub(aligned_vaddr);

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