MIPS: Allow the auxv's elf_platform entry to be set.

The userspace runtime linker uses the elf_platform to find the libraries
optimized for the current CPU archecture variant.  First we need to allow it
to be set to something other than NULL.  Follow-on patches will set some
values for specific CPUs.

GLIBC already does the right thing.  The kernel just needs to supply good
data.

Signed-off-by: David Daney <ddaney@caviumnetworks.com>
To: linux-mips@linux-mips.org
Patchwork: http://patchwork.linux-mips.org/patch/891/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
diff --git a/arch/mips/include/asm/elf.h b/arch/mips/include/asm/elf.h
index 7a6a35d..e53d7be 100644
--- a/arch/mips/include/asm/elf.h
+++ b/arch/mips/include/asm/elf.h
@@ -334,14 +334,14 @@
 
 #define ELF_HWCAP       (0)
 
-/* This yields a string that ld.so will use to load implementation
-   specific libraries for optimization.  This is more specific in
-   intent than poking at uname or /proc/cpuinfo.
+/*
+ * This yields a string that ld.so will use to load implementation
+ * specific libraries for optimization.  This is more specific in
+ * intent than poking at uname or /proc/cpuinfo.
+ */
 
-   For the moment, we have only optimizations for the Intel generations,
-   but that could change... */
-
-#define ELF_PLATFORM  (NULL)
+#define ELF_PLATFORM  __elf_platform
+extern const char *__elf_platform;
 
 /*
  * See comments in asm-alpha/elf.h, this is the same thing