From 86230818ac7bb48f7821d9c41d96a1233c4535c3 Mon Sep 17 00:00:00 2001 From: Will Deacon Date: Tue, 17 Mar 2015 12:15:02 +0000 Subject: arm64: errata: add module build workaround for erratum #843419 commit df057cc7b4fa59e9b55f07ffdb6c62bf02e99a00 upstream. Cortex-A53 processors <= r0p4 are affected by erratum #843419 which can lead to a memory access using an incorrect address in certain sequences headed by an ADRP instruction. There is a linker fix to generate veneers for ADRP instructions, but this doesn't work for kernel modules which are built as unlinked ELF objects. This patch adds a new config option for the erratum which, when enabled, builds kernel modules with the mcmodel=large flag. This uses absolute addressing for all kernel symbols, thereby removing the use of ADRP as a PC-relative form of addressing. The ADRP relocs are removed from the module loader so that we fail to load any potentially affected modules. Acked-by: Catalin Marinas Signed-off-by: Will Deacon Signed-off-by: Jiri Slaby --- arch/arm64/Kconfig | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) (limited to 'arch/arm64/Kconfig') diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index b07f9f356b87..c6ab435557b2 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -269,6 +269,22 @@ config SYSVIPC_COMPAT def_bool y depends on COMPAT && SYSVIPC +config ARM64_ERRATUM_843419 + bool "Cortex-A53: 843419: A load or store might access an incorrect address" + depends on MODULES + default y + help + This option builds kernel modules using the large memory model in + order to avoid the use of the ADRP instruction, which can cause + a subsequent memory access to use an incorrect address on Cortex-A53 + parts up to r0p4. + + Note that the kernel itself must be linked with a version of ld + which fixes potentially affected ADRP instructions through the + use of veneers. + + If unsure, say Y. + endmenu source "net/Kconfig" -- cgit v1.2.3