NX (No eXecute) support for x86, 2.6.7-rc2-bk2

PATCH Andi Kleen 1 participant 1 message Jun 3, 2004 3 messages not in the archive

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Andi Kleen

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2004-06-03 09:43 UTC #3 lore raw

Quoted 10 lines · Ingo Molnar

Quoted 4 lines · Rusty Russell
You want to replace the arch-specific module_alloc() function for this. Or even better, reset the NX bit only on executable sections (in the arch-specific module_finalize(), using mod->core_text_size and mod->init_text_size). No generic changes necessary.
this reminds me of another issue: x86_64 currently seems to manually map the whole module via PAGE_KERNEL_EXEC. Andi, we could change it to use vmalloc_exec(), right?

Nope, the manual map is needed. On x86-64 kernels are linked in the "kernel" code model and the modules must be within 2GB of the main kernel text. vmalloc space is elsewhere.

To fix this you would need to link the modules with -fPIC and add a full dynamic linker to the module loader, which would probably not be worth the effort.

-Andi