options/rtld: Implement relocations in text sections (DT/DF_TEXTREL)#1448
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oberrow wants to merge 6 commits intomanagarm:masterfrom
Open
options/rtld: Implement relocations in text sections (DT/DF_TEXTREL)#1448oberrow wants to merge 6 commits intomanagarm:masterfrom
oberrow wants to merge 6 commits intomanagarm:masterfrom
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Dennisbonke
requested changes
Sep 8, 2025
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Dennisbonke
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Dennisbonke
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Some small issues I spotted in 2 seconds, an in depth review is required before this can be merged.
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Why is this needed? On which architecture / target do you need |
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I have found that my m68k toolchain generates text relocations for PIE executables and for shared libraries, which was a problem for my m68k port. |
avdgrinten
reviewed
Sep 16, 2025
| size_t phdrEntrySize = 0; | ||
| size_t phdrCount = 0; | ||
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| frg::vector<void*, MemoryAllocator> exec_phdrs; |
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We already have phdrPointer etc. which can be used to iterate over the PHDRs.
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| if(object->haveTextRel) { | ||
| for(auto &phdr_ptr : object->exec_phdrs) { | ||
| elf_phdr* phdr = (elf_phdr *)phdr_ptr; | ||
| void* addr = (void *)(phdr->p_vaddr + (uintptr_t)object->baseAddress); | ||
| int prot = PROT_WRITE | PROT_READ | PROT_EXEC; | ||
| if (mlibc::sys_vm_protect) | ||
| mlibc::sys_vm_protect(addr, phdr->p_memsz, prot); | ||
| else | ||
| __ensure(!"sys_vm_protect required when DF_TEXTREL/DT_TEXTREL is present"); | ||
| } | ||
| } |
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This could be done in linkObjects() to be symmetrical with the code path that removes PROT_WRITE again.
| for(auto &phdr_ptr : object->exec_phdrs) { | ||
| elf_phdr* phdr = (elf_phdr *)phdr_ptr; | ||
| void* addr = (void *)(phdr->p_vaddr + (uintptr_t)object->baseAddress); | ||
| int prot = PROT_WRITE | PROT_READ | PROT_EXEC; |
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We should never map as RWX. Instead, map as RW first and then change that to RX.
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