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authorFlorian Weimer <fweimer@redhat.com>2024-04-14 08:24:51 +0200
committerFlorian Weimer <fweimer@redhat.com>2024-04-14 11:02:00 +0200
commit4a7de5e2156447a3c53b779ffe155292e368ba8f (patch)
tree565aebaedb8eb2b8363d06b212269c38bc8a8e5b
parentf4a45af3683adc54bf4b813b56be1fd19e3f1f5a (diff)
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powerpc: Fix ld.so address determination for PCREL mode (bug 31640)
This seems to have stopped working with some GCC 14 versions,
which clobber r2.  With other compilers, the kernel-provided
r2 value is still available at this point.

Reviewed-by: Peter Bergner <bergner@linux.ibm.com>
(cherry picked from commit 14e56bd4ce15ac2d1cc43f762eb2e6b83fec1afe)
-rw-r--r--sysdeps/powerpc/powerpc64/dl-machine.h19
1 files changed, 19 insertions, 0 deletions
diff --git a/sysdeps/powerpc/powerpc64/dl-machine.h b/sysdeps/powerpc/powerpc64/dl-machine.h
index a505998351..76a8217f57 100644
--- a/sysdeps/powerpc/powerpc64/dl-machine.h
+++ b/sysdeps/powerpc/powerpc64/dl-machine.h
@@ -79,6 +79,7 @@ elf_host_tolerates_class (const Elf64_Ehdr *ehdr)
 static inline Elf64_Addr
 elf_machine_load_address (void) __attribute__ ((const));
 
+#ifndef __PCREL__
 static inline Elf64_Addr
 elf_machine_load_address (void)
 {
@@ -106,6 +107,24 @@ elf_machine_dynamic (void)
   /* Then subtract off the load address offset.  */
   return runtime_dynamic - elf_machine_load_address() ;
 }
+#else /* __PCREL__ */
+/* In PCREL mode, r2 may have been clobbered.  Rely on relative
+   relocations instead.  */
+
+static inline ElfW(Addr)
+elf_machine_load_address (void)
+{
+  extern const ElfW(Ehdr) __ehdr_start attribute_hidden;
+  return (ElfW(Addr)) &__ehdr_start;
+}
+
+static inline ElfW(Addr)
+elf_machine_dynamic (void)
+{
+  extern ElfW(Dyn) _DYNAMIC[] attribute_hidden;
+  return (ElfW(Addr)) _DYNAMIC - elf_machine_load_address ();
+}
+#endif /* __PCREL__ */
 
 /* The PLT uses Elf64_Rela relocs.  */
 #define elf_machine_relplt elf_machine_rela