[PATCH] Fix hwcap handling in ld.so

[PATCH] Fix hwcap handling in ld.so

[Jakub Jelinek]

Hi!

Wonder why this has been broken for so long unnoticed.
unsigned long long x, y;
...
(x & y) > x
is 0 for any x, y.
Guess I should add a GCC warning for this kind of things.

I believe the following patch is correct and seems to work for me
on both PIII (where it doesn't decide to use a /usr/lib/sse2/ library
neither without nor with LD_LIBRARY_PATH=/usr/lib, without this
patch it happily uses /usr/lib/sse2/ library without
LD_LIBRARY_PATH=/usr/lib, but doesn't use it with the env var)
and on x86-64 (where it uses /usr/lib/sse2/).
When GLRO(dl_osversion) is referenced in dl-cache.c, I don't see how
GLRO(dl_hwcap) could be undefined, since it is for statically linked
apps defined in dl-support.c together with _dl_osversion.

2004-03-18  Jakub Jelinek  <jakub@redhat.com>

	* sysdeps/generic/dl-cache.c (_dl_load_cache_lookup): Remove hwcap
	variable and weak_extern for _dl_hwcap.
	(_DL_HWCAP_TLS_MASK): Define.
	(HWCAP_CHECK): Fix checking of non-platform hwcap bits.  Use
	lib->osversion instead of cache_new->libs[middle].osversion.

--- libc/sysdeps/generic/dl-cache.c.jj	2004-03-08 12:01:51.000000000 +0100
+++ libc/sysdeps/generic/dl-cache.c	2004-03-18 14:55:34.774381649 +0100
@@ -243,12 +243,7 @@ _dl_load_cache_lookup (const char *name)
 
   if (cache_new != (void *) -1)
     {
-      /* This file ends in static libraries where we don't have a hwcap.  */
-      unsigned long int *hwcap;
       uint64_t platform;
-#ifndef SHARED
-      weak_extern (_dl_hwcap);
-#endif
 
       /* This is where the strings start.  */
       cache_data = (const char *) cache_new;
@@ -256,22 +251,25 @@ _dl_load_cache_lookup (const char *name)
       /* Now we can compute how large the string table is.  */
       cache_data_size = (const char *) cache + cachesize - cache_data;
 
-      hwcap = &GLRO(dl_hwcap);
       platform = _dl_string_platform (GLRO(dl_platform));
       if (platform != (uint64_t) -1)
 	platform = 1ULL << platform;
 
       /* Only accept hwcap if it's for the right platform.  */
+#ifdef USE_TLS
+# define _DL_HWCAP_TLS_MASK (1LL << 63)
+#else
+# define _DL_HWCAP_TLS_MASK 0
+#endif
 #define HWCAP_CHECK \
-      if (GLRO(dl_osversion)						      \
-	  && cache_new->libs[middle].osversion > GLRO(dl_osversion))	      \
+      if (GLRO(dl_osversion) && lib->osversion > GLRO(dl_osversion))	      \
 	continue;							      \
       if (_DL_PLATFORMS_COUNT && platform != -1				      \
 	  && (lib->hwcap & _DL_HWCAP_PLATFORM) != 0			      \
 	  && (lib->hwcap & _DL_HWCAP_PLATFORM) != platform)		      \
 	continue;							      \
-      if (hwcap								      \
-	  && ((lib->hwcap & *hwcap & ~_DL_HWCAP_PLATFORM) > *hwcap))	      \
+      if (lib->hwcap							      \
+	  & ~(GLRO(dl_hwcap) | _DL_HWCAP_PLATFORM | _DL_HWCAP_TLS_MASK))      \
 	continue
       SEARCH_CACHE (cache_new);
     }

	Jakub