The Challenge of Loading 4kB-Aligned ELFs on 16kB Systems

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" summary

Devices gain ~30% app launch and ~5–7.5% power savings by moving to 16k pages, but legacy 4k-aligned ELFs put RX and RW segments in one page. A modified dynamic loader implements re-read/re-executable rewrite consolidation, mapping combined permissions into an anonymous region and shifting the boundary, which raises compatibility from 44% to 74% and with extra checks to 91.4% then 94% compatibility on top apps. A subpage MFD approach proved correct but up to 15x slower and incompatible with syscall and obfuscated custom-loaders, while binary rewriting fails due to stripped relocation info and mixed code/data.

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" chapters (10)

1. 0:00Introduction
2. 0:22Benefits of 16k page sizes
3. 1:28Problem with 4k alignment
4. 2:08Dynamic loader approach
5. 3:34Handling linker script bugs
6. 4:39Custom ELF layouts challenge
7. 6:28Compatibility improvements
8. 6:50Attempting ELF rewrite
9. 8:38Remaining 6% of apps
10. 10:46Open discussion and Q&A