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 ? Christophe
