Add support for DT_MIPS_RLD_MAP_REL.

This tag allows debugging of MIPS position independent executables
and provides access to shared library information.

	* elf/elf.h (DT_MIPS_RLD_MAP_REL): New macro.
	(DT_MIPS_NUM): Update.
	* sysdeps/mips/dl-machine.h (ELF_MACHINE_DEBUG_SETUP): Handle
	DT_MIPS_RLD_MAP_REL.

3 files changed, 22 insertions, 4 deletions

diff --git a/ChangeLog b/ChangeLog
index b61ea3cec9..b502c78f89 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+2015-06-26  Matthew Fortune  <matthew.fortune@imgtec.com>
+
+	* elf/elf.h (DT_MIPS_RLD_MAP_REL): New macro.
+	(DT_MIPS_NUM): Update.
+	* sysdeps/mips/dl-machine.h (ELF_MACHINE_DEBUG_SETUP): Handle
+	DT_MIPS_RLD_MAP_REL.
+
 2015-06-25  Joseph Myers  <joseph@codesourcery.com>
 
 	[BZ #16559]
diff --git a/elf/elf.h b/elf/elf.h
index 12feb915bf..fbadda4377 100644
--- a/elf/elf.h
+++ b/elf/elf.h
@@ -1727,7 +1727,11 @@ typedef struct
    PLT is writable.  For a non-writable PLT, this is omitted or has a zero
    value.  */
 #define DT_MIPS_RWPLT        0x70000034
-#define DT_MIPS_NUM	     0x35
+/* An alternative description of the classic MIPS RLD_MAP that is usable
+   in a PIE as it stores a relative offset from the address of the tag
+   rather than an absolute address.  */
+#define DT_MIPS_RLD_MAP_REL  0x70000035
+#define DT_MIPS_NUM	     0x36
 
 /* Legal values for DT_MIPS_FLAGS Elf32_Dyn entry.  */
 
diff --git a/sysdeps/mips/dl-machine.h b/sysdeps/mips/dl-machine.h
index d63238a4fe..8738564241 100644
--- a/sysdeps/mips/dl-machine.h
+++ b/sysdeps/mips/dl-machine.h
@@ -68,10 +68,17 @@
    in l_info array.  */
 #define DT_MIPS(x) (DT_MIPS_##x - DT_LOPROC + DT_NUM)
 
-/* If there is a DT_MIPS_RLD_MAP entry in the dynamic section, fill it in
-   with the run-time address of the r_debug structure  */
+/* If there is a DT_MIPS_RLD_MAP_REL or DT_MIPS_RLD_MAP entry in the dynamic
+   section, fill in the debug map pointer with the run-time address of the
+   r_debug structure.  */
 #define ELF_MACHINE_DEBUG_SETUP(l,r) \
-do { if ((l)->l_info[DT_MIPS (RLD_MAP)]) \
+do { if ((l)->l_info[DT_MIPS (RLD_MAP_REL)]) \
+       { \
+	 char *ptr = (char *)(l)->l_info[DT_MIPS (RLD_MAP_REL)]; \
+	 ptr += (l)->l_info[DT_MIPS (RLD_MAP_REL)]->d_un.d_val; \
+	 *(ElfW(Addr) *)ptr = (ElfW(Addr)) (r); \
+       } \
+     else if ((l)->l_info[DT_MIPS (RLD_MAP)]) \
        *(ElfW(Addr) *)((l)->l_info[DT_MIPS (RLD_MAP)]->d_un.d_ptr) = \
        (ElfW(Addr)) (r); \
    } while (0)