> On Wednesday, February 21, 2024 at 1:32 AM, Christophe Leroy wrote: > > On powerpc (book3s/32) we have more or less the same although it is not > directly linked to PMDs: the virtual 4G address space is split in > segments of 256M. On each segment there's a bit called NX to forbit > execution. Vmalloc space is allocated in a segment with NX bit set while > Module spare is allocated in a segment with NX bit unset. We never have > to override vmalloc wrappers. All consumers of exec memory allocate it > using module_alloc() while vmalloc() provides non-exec memory. > > For modules, all you have to do is select > ARCH_WANTS_MODULES_DATA_IN_VMALLOC and module data will be allocated > using vmalloc() hence non-exec memory in our case. This critique has led me to some valuable ideas, and I can definitely find a simpler approach without overrides. I do want to mention changes to how VMALLOC_* and MODULE_* constants are used on arm64 may introduce other issues. See discussion/code on the patch that motivated this patch at: https://lore.kernel.org/all/CAP5Mv+ydhk=Ob4b40ZahGMgT-5+-VEHxtmA=-LkJiEOOU+K6hw@xxxxxxxxxxxxxx/ In short, maybe the issue of code/data intermixing requires a rework of arm64 memory infrastructure, but I see a potentially elegant solution here based on the comments given on this patch. Thanks, Maxwell
