powerpc: Select ARCH_WANTS_MODULES_DATA_IN_VMALLOC on book3s/32 and 8xx

JIRA: https://issues.redhat.com/browse/RHEL-27743

This patch is a backport of the following upstream commit:
commit eeaec7801c421e17edda6e45a32d4a5596b633da
Author: Christophe Leroy <christophe.leroy@csgroup.eu>
Date:   Wed Feb 23 13:02:16 2022 +0100

    powerpc: Select ARCH_WANTS_MODULES_DATA_IN_VMALLOC on book3s/32 and 8xx

    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@csgroup.eu>
    Cc: Michael Ellerman <mpe@ellerman.id.au>
    Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
    Cc: Paul Mackerras <paulus@samba.org>
    Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>

Signed-off-by: Rafael Aquini <raquini@redhat.com>
This commit is contained in:
Rafael Aquini 2024-09-27 10:44:12 -04:00
parent e4d3e92cb7
commit 70e7c80794
1 changed files with 1 additions and 0 deletions

View File

@ -152,6 +152,7 @@ config PPC
select ARCH_WANT_IPC_PARSE_VERSION
select ARCH_WANT_IRQS_OFF_ACTIVATE_MM
select ARCH_WANT_LD_ORPHAN_WARN
select ARCH_WANTS_MODULES_DATA_IN_VMALLOC if PPC_BOOK3S_32 || PPC_8xx
select ARCH_WEAK_RELEASE_ACQUIRE
select BINFMT_ELF
select BUILDTIME_TABLE_SORT