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authorArd Biesheuvel <ard.biesheuvel@linaro.org>2018-08-29 08:47:53 +0200
committerLinus Torvalds <torvalds@linux-foundation.org>2018-08-29 16:12:07 -0700
commitff69279a44e9ba876466b7d3ab84d6dbd31cac92 (patch)
tree6b90dd75b639e091ae9fa5be146222132b69b50e
parentaf3a5fe4ddfe3d426eb025d4c3afd176efea658e (diff)
download96b-common-ff69279a44e9ba876466b7d3ab84d6dbd31cac92.tar.gz
powerpc: disable support for relative ksymtab references
The newly added code that emits ksymtab entries as pairs of 32-bit relative references interacts poorly with the way powerpc lays out its address space: when a module exports a per-CPU variable, the primary module region covering the ksymtab entry -and thus the 32-bit relative reference- is too far away from the actual per-CPU variable's base address (to which the per-CPU offsets are applied to obtain the respective address of each CPU's copy), resulting in corruption when the module loader attempts to resolve symbol references of modules that are loaded on top and link to the exported per-CPU symbol. So let's disable this feature on powerpc. Even though it implements CONFIG_RELOCATABLE, it does not implement CONFIG_RANDOMIZE_BASE and so KASLR kernels (which are the main target of the feature) do not exist on powerpc anyway. Reported-by: Andreas Schwab <schwab@linux-m68k.org> Suggested-by: Nicholas Piggin <nicholas.piggin@gmail.com> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--arch/powerpc/Kconfig1
1 files changed, 0 insertions, 1 deletions
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index db0b6eebbfa5..a80669209155 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -177,7 +177,6 @@ config PPC
select HAVE_ARCH_KGDB
select HAVE_ARCH_MMAP_RND_BITS
select HAVE_ARCH_MMAP_RND_COMPAT_BITS if COMPAT
- select HAVE_ARCH_PREL32_RELOCATIONS
select HAVE_ARCH_SECCOMP_FILTER
select HAVE_ARCH_TRACEHOOK
select HAVE_CBPF_JIT if !PPC64