path: root/scripts
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authorAlan Modra <amodra@gmail.com>2016-01-15 20:52:22 +1100
committerMichael Ellerman <mpe@ellerman.id.au>2016-01-21 14:10:56 +1100
commitc153693d7eb9eeb28478aa2deaaf0b4e7b5ff5e9 (patch)
tree936e397baad3b55ed7f1306b01e60053325c2bb2 /scripts
parentpowerpc: Wire up copy_file_range() syscall (diff)
powerpc: Simplify module TOC handling
PowerPC64 uses the symbol .TOC. much as other targets use _GLOBAL_OFFSET_TABLE_. It identifies the value of the GOT pointer (or in powerpc parlance, the TOC pointer). Global offset tables are generally local to an executable or shared library, or in the kernel, module. Thus it does not make sense for a module to resolve a relocation against .TOC. to the kernel's .TOC. value. A module has its own .TOC., and indeed the powerpc64 module relocation processing ignores the kernel value of .TOC. and instead calculates a module-local value. This patch removes code involved in exporting the kernel .TOC., tweaks modpost to ignore an undefined .TOC., and the module loader to twiddle the section symbol so that .TOC. isn't seen as undefined. Note that if the kernel was compiled with -msingle-pic-base then ELFv2 would not have function global entry code setting up r2. In that case the module call stubs would need to be modified to set up r2 using the kernel .TOC. value, requiring some of this code to be reinstated. mpe: Furthermore a change in binutils master (not yet released) causes the current way we handle the TOC to no longer work when building with MODVERSIONS=y and RELOCATABLE=n. The symptom is that modules can not be loaded due to there being no version found for TOC. Cc: stable@vger.kernel.org # 3.16+ Signed-off-by: Alan Modra <amodra@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'scripts')
1 files changed, 2 insertions, 1 deletions
diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
index e080746e1a6b..48958d3cec9e 100644
--- a/scripts/mod/modpost.c
+++ b/scripts/mod/modpost.c
@@ -594,7 +594,8 @@ static int ignore_undef_symbol(struct elf_info *info, const char *symname)
if (strncmp(symname, "_restgpr0_", sizeof("_restgpr0_") - 1) == 0 ||
strncmp(symname, "_savegpr0_", sizeof("_savegpr0_") - 1) == 0 ||
strncmp(symname, "_restvr_", sizeof("_restvr_") - 1) == 0 ||
- strncmp(symname, "_savevr_", sizeof("_savevr_") - 1) == 0)
+ strncmp(symname, "_savevr_", sizeof("_savevr_") - 1) == 0 ||
+ strcmp(symname, ".TOC.") == 0)
return 1;
/* Do not ignore this symbol */
return 0;