arm64: errata: add module build workaround for erratum #843419

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[ Upstream commit df057cc7b4 ]

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.

Cc: <stable@vger.kernel.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>

...

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Will Deacon 2015-03-17 12:15:02 +00:00 • committed by Sasha Levin

parent dbb4b0e5a9

commit be9d2b0eaf

3 changed files with 22 additions and 0 deletions

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16

arch/arm64/Kconfig

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4

arch/arm64/Makefile

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2

arch/arm64/kernel/module.c

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