2 * Copyright (C) 2005-2013 Free Software Foundation, Inc.
4 * This file is free software; you can redistribute it and/or modify it
5 * under the terms of the GNU General Public License as published by the
6 * Free Software Foundation; either version 3, or (at your option) any
9 * This file is distributed in the hope that it will be useful, but
10 * WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * General Public License for more details.
14 * Under Section 7 of GPL version 3, you are granted additional
15 * permissions described in the GCC Runtime Library Exception, version
16 * 3.1, as published by the Free Software Foundation.
18 * You should have received a copy of the GNU General Public License and
19 * a copy of the GCC Runtime Library Exception along with this program;
20 * see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
21 * <http://www.gnu.org/licenses/>.
24 #define MXCSR_DAZ (1 << 6) /* Enable denormals are zero mode */
25 #define MXCSR_FTZ (1 << 15) /* Enable flush to zero mode */
28 /* All 64-bit targets have SSE and DAZ;
29 only check them explicitly for 32-bit ones. */
33 #if !defined __x86_64__ && defined __sun__ && defined __svr4__
37 static volatile sig_atomic_t sigill_caught
;
40 sigill_hdlr (int sig
__attribute((unused
)),
41 siginfo_t
*sip
__attribute__((unused
)),
45 /* Set PC to the instruction after the faulting one to skip over it,
46 otherwise we enter an infinite loop. 3 is the size of the movaps
48 ucp
->uc_mcontext
.gregs
[EIP
] += 3;
53 static void __attribute__((constructor
))
55 /* The i386 ABI only requires 4-byte stack alignment, so this is necessary
56 to make sure the fxsave struct gets correct alignment.
57 See PR27537 and PR28621. */
58 __attribute__ ((force_align_arg_pointer
))
63 unsigned int eax
, ebx
, ecx
, edx
;
65 if (!__get_cpuid (1, &eax
, &ebx
, &ecx
, &edx
))
72 #if defined __sun__ && defined __svr4__
73 /* Solaris 2 before Solaris 9 4/04 cannot execute SSE instructions even
74 if the CPU supports them. Programs receive SIGILL instead, so check
75 for that at runtime. */
76 struct sigaction act
, oact
;
78 act
.sa_handler
= sigill_hdlr
;
79 sigemptyset (&act
.sa_mask
);
80 /* Need to set SA_SIGINFO so a ucontext_t * is passed to the handler. */
81 act
.sa_flags
= SA_SIGINFO
;
82 sigaction (SIGILL
, &act
, &oact
);
84 /* We need a single SSE instruction here so the handler can safely skip
86 __asm__
volatile ("movaps %xmm0,%xmm0");
88 sigaction (SIGILL
, &oact
, NULL
);
92 #endif /* __sun__ && __svr4__ */
96 /* Check if DAZ is available. */
108 unsigned int mxcsr_mask
;
109 unsigned int st_space
[32];
110 unsigned int xmm_space
[32];
111 unsigned int padding
[56];
112 } __attribute__ ((aligned (16))) fxsave
;
114 /* This is necessary since some implementations of FXSAVE
115 do not modify reserved areas within the image. */
116 fxsave
.mxcsr_mask
= 0;
118 __builtin_ia32_fxsave (&fxsave
);
120 mxcsr
= fxsave
.mxcsr
;
122 if (fxsave
.mxcsr_mask
& MXCSR_DAZ
)
126 mxcsr
= __builtin_ia32_stmxcsr ();
129 __builtin_ia32_ldmxcsr (mxcsr
);
132 unsigned int mxcsr
= __builtin_ia32_stmxcsr ();
133 mxcsr
|= MXCSR_DAZ
| MXCSR_FTZ
;
134 __builtin_ia32_ldmxcsr (mxcsr
);