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| author |   Christophe Leroy <christophe.leroy@csgroup.eu> | 2022-02-23 13:02:16 +0100 |
|---|---|---|
| committer |   Luis Chamberlain <mcgrof@kernel.org> | 2022-04-05 08:43:05 -0700 |
| commit | eeaec7801c421e17edda6e45a32d4a5596b633da (patch) | |
| tree | 1a0be4fb023c7404af828c20ec76a10bc64ac7b6 /arch/powerpc/Kconfig | |
| parent | module: Remove module_addr_min and module_addr_max (diff) | |
| download | linux-dev-eeaec7801c421e17edda6e45a32d4a5596b633da.tar.xz linux-dev-eeaec7801c421e17edda6e45a32d4a5596b633da.zip | |
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>
Diffstat (limited to 'arch/powerpc/Kconfig')
| -rw-r--r-- | arch/powerpc/Kconfig | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig index 174edabb74fa..0b7bcfa63d0d 100644 --- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig @@ -157,6 +157,7 @@ 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 |