Preserve SSE registers in runtime relocations on x86-64.

SSE registers are used for passing parameters and must be preserved
in runtime relocations.  This is inside ld.so enforced through the
tests in tst-xmmymm.sh.  But the malloc routines used after startup
come from libc.so and can be arbitrarily complex.  It's overkill
to save the SSE registers all the time because of that.  These calls
are rare.  Instead we save them on demand.  The new infrastructure
put in place in this patch makes this possible and efficient.

2 files changed, 56 insertions, 18 deletions

diff --git a/nptl/sysdeps/x86_64/tcb-offsets.sym b/nptl/sysdeps/x86_64/tcb-offsets.sym
index 1c70c6bde7..51f35c61cf 100644
--- a/nptl/sysdeps/x86_64/tcb-offsets.sym
+++ b/nptl/sysdeps/x86_64/tcb-offsets.sym
@@ -15,3 +15,4 @@ VGETCPU_CACHE_OFFSET	offsetof (tcbhead_t, vgetcpu_cache)
 #ifndef __ASSUME_PRIVATE_FUTEX
 PRIVATE_FUTEX		offsetof (tcbhead_t, private_futex)
 #endif
+RTLD_SAVESPACE_SSE	offsetof (tcbhead_t, rtld_savespace_sse)
diff --git a/nptl/sysdeps/x86_64/tls.h b/nptl/sysdeps/x86_64/tls.h
index ea89f3b1a2..a51b77052a 100644
--- a/nptl/sysdeps/x86_64/tls.h
+++ b/nptl/sysdeps/x86_64/tls.h
@@ -29,6 +29,7 @@
 # include <sysdep.h>
 # include <kernel-features.h>
 # include <bits/wordsize.h>
+# include <xmmintrin.h>
 
 
 /* Type for the dtv.  */
@@ -55,16 +56,23 @@ typedef struct
   uintptr_t stack_guard;
   uintptr_t pointer_guard;
   unsigned long int vgetcpu_cache[2];
-#ifndef __ASSUME_PRIVATE_FUTEX
+# ifndef __ASSUME_PRIVATE_FUTEX
   int private_futex;
-#else
+# else
   int __unused1;
-#endif
-#if __WORDSIZE == 64
-  int __pad1;
-#endif
+# endif
+# if __WORDSIZE == 64
+  int rtld_must_xmm_save;
+# endif
   /* Reservation of some values for the TM ABI.  */
   void *__private_tm[5];
+# if __WORDSIZE == 64
+  long int __unused2;
+  /* Have space for the post-AVX register size.  */
+  __m128 rtld_savespace_sse[8][4];
+
+  void *__padding[8];
+# endif
 } tcbhead_t;
 
 #else /* __ASSEMBLER__ */
@@ -298,7 +306,7 @@ typedef struct
 
 
 /* Atomic compare and exchange on TLS, returning old value.  */
-#define THREAD_ATOMIC_CMPXCHG_VAL(descr, member, newval, oldval) \
+# define THREAD_ATOMIC_CMPXCHG_VAL(descr, member, newval, oldval) \
   ({ __typeof (descr->member) __ret;					      \
      __typeof (oldval) __old = (oldval);				      \
      if (sizeof (descr->member) == 4)					      \
@@ -313,7 +321,7 @@ typedef struct
 
 
 /* Atomic logical and.  */
-#define THREAD_ATOMIC_AND(descr, member, val) \
+# define THREAD_ATOMIC_AND(descr, member, val) \
   (void) ({ if (sizeof ((descr)->member) == 4)				      \
 	      asm volatile (LOCK_PREFIX "andl %1, %%fs:%P0"		      \
 			    :: "i" (offsetof (struct pthread, member)),	      \
@@ -324,7 +332,7 @@ typedef struct
 
 
 /* Atomic set bit.  */
-#define THREAD_ATOMIC_BIT_SET(descr, member, bit) \
+# define THREAD_ATOMIC_BIT_SET(descr, member, bit) \
   (void) ({ if (sizeof ((descr)->member) == 4)				      \
 	      asm volatile (LOCK_PREFIX "orl %1, %%fs:%P0"		      \
 			    :: "i" (offsetof (struct pthread, member)),	      \
@@ -334,7 +342,7 @@ typedef struct
 	      abort (); })
 
 
-#define CALL_THREAD_FCT(descr) \
+# define CALL_THREAD_FCT(descr) \
   ({ void *__res;							      \
      asm volatile ("movq %%fs:%P2, %%rdi\n\t"				      \
 		   "callq *%%fs:%P1"					      \
@@ -355,18 +363,18 @@ typedef struct
 
 
 /* Set the pointer guard field in the TCB head.  */
-#define THREAD_SET_POINTER_GUARD(value) \
+# define THREAD_SET_POINTER_GUARD(value) \
   THREAD_SETMEM (THREAD_SELF, header.pointer_guard, value)
-#define THREAD_COPY_POINTER_GUARD(descr) \
+# define THREAD_COPY_POINTER_GUARD(descr) \
   ((descr)->header.pointer_guard					      \
    = THREAD_GETMEM (THREAD_SELF, header.pointer_guard))
 
 
 /* Get and set the global scope generation counter in the TCB head.  */
-#define THREAD_GSCOPE_FLAG_UNUSED 0
-#define THREAD_GSCOPE_FLAG_USED   1
-#define THREAD_GSCOPE_FLAG_WAIT   2
-#define THREAD_GSCOPE_RESET_FLAG() \
+# define THREAD_GSCOPE_FLAG_UNUSED 0
+# define THREAD_GSCOPE_FLAG_USED   1
+# define THREAD_GSCOPE_FLAG_WAIT   2
+# define THREAD_GSCOPE_RESET_FLAG() \
   do									      \
     { int __res;							      \
       asm volatile ("xchgl %0, %%fs:%P1"				      \
@@ -377,11 +385,40 @@ typedef struct
 	lll_futex_wake (&THREAD_SELF->header.gscope_flag, 1, LLL_PRIVATE);    \
     }									      \
   while (0)
-#define THREAD_GSCOPE_SET_FLAG() \
+# define THREAD_GSCOPE_SET_FLAG() \
   THREAD_SETMEM (THREAD_SELF, header.gscope_flag, THREAD_GSCOPE_FLAG_USED)
-#define THREAD_GSCOPE_WAIT() \
+# define THREAD_GSCOPE_WAIT() \
   GL(dl_wait_lookup_done) ()
 
+
+# ifdef SHARED
+/* Defined in dl-trampoline.S.  */
+extern void _dl_x86_64_save_sse (void);
+extern void _dl_x86_64_restore_sse (void);
+
+# define RTLD_CHECK_FOREIGN_CALL \
+  (THREAD_GETMEM (THREAD_SELF, header.rtld_must_xmm_save) != 0)
+
+#  define RTLD_ENABLE_FOREIGN_CALL \
+  THREAD_SETMEM (THREAD_SELF, header.rtld_must_xmm_save, 1)
+
+#  define RTLD_PREPARE_FOREIGN_CALL \
+  do if (THREAD_GETMEM (THREAD_SELF, header.rtld_must_xmm_save))	      \
+    {									      \
+      _dl_x86_64_save_sse ();						      \
+      THREAD_SETMEM (THREAD_SELF, header.rtld_must_xmm_save, 0);	      \
+    }									      \
+  while (0)
+
+#  define RTLD_FINALIZE_FOREIGN_CALL \
+  do {									      \
+    if (THREAD_GETMEM (THREAD_SELF, header.rtld_must_xmm_save) == 0)	      \
+      _dl_x86_64_restore_sse ();					      \
+    THREAD_SETMEM (THREAD_SELF, header.rtld_must_xmm_save, 0);		      \
+  } while (0)
+# endif
+
+
 #endif /* __ASSEMBLER__ */
 
 #endif	/* tls.h */