* sysdeps/x86-64/dl-machine.h (elf_machine_load_address): Rewrite

to not use 32-bit pc relative relocations. 
(elf_machine_dynamic): Likewise.

1 files changed, 47 insertions, 6 deletions

diff --git a/sysdeps/x86_64/dl-machine.h b/sysdeps/x86_64/dl-machine.h
index 2e2eb9f..3f113f8 100644
--- a/sysdeps/x86_64/dl-machine.h
+++ b/sysdeps/x86_64/dl-machine.h
@@ -39,9 +39,12 @@ elf_machine_matches_host (const Elf64_Ehdr *ehdr)
 static inline Elf64_Addr __attribute__ ((unused))
 elf_machine_dynamic (void)
 {
-  register Elf64_Addr addr;
+  Elf64_Addr addr;
+
+  /* This works because we have our GOT address available in the small PIC
+     model.  */
+  addr = (Elf64_Addr) &_DYNAMIC;
 
-  asm ("leaq _DYNAMIC, %0\n" : "=r" (addr));
   return addr;
 }
 
@@ -52,10 +55,25 @@ elf_machine_load_address (void)
 {
   register Elf64_Addr addr, tmp;
 
-  asm ("leaq _dl_start, %0\n"
-       "leaq _dl_start(%%rip), %1\n"
-       "subq %0, %1\n"
-       : "=r" (tmp), "=r" (addr) : : "cc");
+  /* The easy way is just the same as on x86:
+       leaq _dl_start, %0
+       leaq _dl_start(%%rip), %1
+       subq %0, %1
+     but this does not work with binutils since we then have
+     a R_X86_64_32S relocation in a shared lib.
+
+     Instead we store the address of _dl_start in the data section
+     and compare it with the current value that we can get via
+     an RIP relative addressing mode.  */
+
+  asm ("movq .L1(%%rip), %1\n"
+       "0:\tleaq _dl_start(%%rip), %0\n\t"
+       "subq %1, %0\n\t"
+       ".section\t.data\n"
+       ".L1:\t.quad _dl_start\n\t"
+       ".previous\n\t"
+       : "=r" (addr), "=r" (tmp) : : "cc");
+
   return addr;
 }
 
@@ -367,10 +385,33 @@ elf_machine_rela (struct link_map *map, const Elf64_Rela *reloc,
 	  break;
 	case R_X86_64_32:
 	  *(unsigned int *) reloc_addr = value + reloc->r_addend;
+	  if (value + reloc->r_addend > UINT_MAX)
+	    {
+	      const char *strtab;
+
+	      strtab = (const char *) D_PTR (map, l_info[DT_STRTAB]);
+
+	      _dl_error_printf ("\
+%s: Symbol `%s' causes overflow in R_X86_64_32 relocation\n",
+				rtld_progname ?: "<program name unknown>",
+				strtab + refsym->st_name);
+	    }
 	  break;
 	case R_X86_64_PC32:
 	  *(unsigned int *) reloc_addr = value + reloc->r_addend
 	    - (Elf64_Addr) reloc_addr;
+	  if (value + reloc->r_addend - (Elf64_Addr) reloc_addr
+	      != (unsigned int)(value + reloc->r_addend - (Elf64_Addr) reloc_addr))
+	    {
+	      const char *strtab;
+
+	      strtab = (const char *) D_PTR (map, l_info[DT_STRTAB]);
+
+	      _dl_error_printf ("\
+%s: Symbol `%s' causes overflow in R_X86_64_PC32 relocation\n",
+				rtld_progname ?: "<program name unknown>",
+				strtab + refsym->st_name);
+	    }
 	  break;
 	case R_X86_64_COPY:
 	  if (sym == NULL)