Christophe Leroy <christophe.leroy@xxxxxxxxxx> writes: > Le 03/02/2022 à 06:39, Michael Ellerman a écrit : >> Luis Chamberlain <mcgrof@xxxxxxxxxx> writes: >>> On Thu, Jan 27, 2022 at 11:28:12AM +0000, Christophe Leroy wrote: >>>> book3s/32 and 8xx have a separate area for allocating modules, >>>> defined by MODULES_VADDR / MODULES_END. >>>> >>>> On book3s/32, it is not possible to protect against execution >>>> on a page basis. A full 256M segment is either Exec or NoExec. >>>> The module area is in an Exec segment while vmalloc area is >>>> in a NoExec segment. >>>> >>>> In order to protect module data against execution, select >>>> ARCH_WANTS_MODULES_DATA_IN_VMALLOC. >>>> >>>> For the 8xx (and possibly other 32 bits platform in the future), >>>> there is no such constraint on Exec/NoExec protection, however >>>> there is a critical distance between kernel functions and callers >>>> that needs to remain below 32Mbytes in order to avoid costly >>>> trampolines. By allocating data outside of module area, we >>>> increase the chance for module text to remain within acceptable >>>> distance from kernel core text. >>>> >>>> So select ARCH_WANTS_MODULES_DATA_IN_VMALLOC for 8xx as well. >>>> >>>> Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxxxxxx> >>>> Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx> >>>> Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx> >>>> Cc: Paul Mackerras <paulus@xxxxxxxxx> >>> >>> Cc list first and then the SOB. >> >> Just delete the Cc: list, it's meaningless. >> > > Was an easy way to copy you automatically with 'git send-email', but > getting it through linuxppc-dev list is enough I guess ? It's useful for making the tooling Cc the right people, it's fine to use them for that. But there's no value in committing them to the git history, I actively strip them when applying. The fact that someone is Cc'ed on a patch tells you nothing, given the volume of mail maintainers receive. The link tag back to the original submission gives you the Cc list anyway. cheers
