Fix static-binary lazy FPU context allocation

Long ago static startup did not parse the auxiliary vector and therefore
could not get at any `AT_FPUCW' tag to check whether upon FPU context
allocation the kernel would use a FPU control word setting different to
that provided by the `__fpu_control' variable.  Static startup therefore
always initialized the FPU control word, forcing immediate FPU context
allocation even for binaries that otherwise never used the FPU.

As from GIT commit f8f900ecb9096ec47f5b7bb7626e29223c69061a static
startup supports parsing the auxiliary vector, so now it can avoid
explicit initialization of the FPU control word, just as can dynamic
startup, in the usual case where the setting written to the FPU control
word would be the same as the kernel uses.  This defers FPU context
allocation until the binary itself actually pokes at the FPU.

Note that the `AT_FPUCW' tag is usually absent from the auxiliary vector
in which case _FPU_DEFAULT is assumed to be the kernel default.

1 files changed, 1 insertions, 4 deletions

diff --git a/csu/init-first.c b/csu/init-first.c
index f0ebc94b8d..b4d22ce6aa 100644
--- a/csu/init-first.c
+++ b/csu/init-first.c
@@ -61,11 +61,8 @@ _init (int argc, char **argv, char **envp)
   if (!__libc_multiple_libcs)
     {
       /* Set the FPU control word to the proper default value if the
-	 kernel would use a different value.  (In a static program we
-	 don't have this information.)  */
-#ifdef SHARED
+	 kernel would use a different value.  */
       if (__fpu_control != GLRO(dl_fpu_control))
-#endif
 	__setfpucw (__fpu_control);
     }