Home Explore Help
Sign In
GfA
/
linux_kernel
5
0
Fork 0
Files Issues 0 Pull Requests 0 Wiki
Browse Source

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>
Ard Biesheuvel 7 years ago
parent
af3a5fe4dd
commit
ff69279a44
1 changed files with 0 additions and 1 deletions
Unified View Show Diff Stats
  1. 0 1
      arch/powerpc/Kconfig

+ 0 - 1
arch/powerpc/Kconfig
View File 

@@ -177,7 +177,6 @@ config PPC
 
 	select HAVE_ARCH_KGDB
 
 	select HAVE_ARCH_KGDB
 
 	select HAVE_ARCH_MMAP_RND_BITS
 
 	select HAVE_ARCH_MMAP_RND_BITS
 
 	select HAVE_ARCH_MMAP_RND_COMPAT_BITS	if COMPAT
 
 	select HAVE_ARCH_MMAP_RND_COMPAT_BITS	if COMPAT
 
-	select HAVE_ARCH_PREL32_RELOCATIONS
 
 	select HAVE_ARCH_SECCOMP_FILTER
 
 	select HAVE_ARCH_SECCOMP_FILTER
 
 	select HAVE_ARCH_TRACEHOOK
 
 	select HAVE_ARCH_TRACEHOOK
 
 	select HAVE_CBPF_JIT			if !PPC64
 
 	select HAVE_CBPF_JIT			if !PPC64