src/mesa/x86/common_x86.c

   1 /*
   2  * Mesa 3-D graphics library
   3  * Version:  6.0.1
   4  *
   5  * Copyright (C) 1999-2004  Brian Paul   All Rights Reserved.
   6  *
   7  * Permission is hereby granted, free of charge, to any person obtaining a
   8  * copy of this software and associated documentation files (the "Software"),
   9  * to deal in the Software without restriction, including without limitation
  10  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  11  * and/or sell copies of the Software, and to permit persons to whom the
  12  * Software is furnished to do so, subject to the following conditions:
  13  *
  14  * The above copyright notice and this permission notice shall be included
  15  * in all copies or substantial portions of the Software.
  16  *
  17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  18  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  20  * BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
  21  * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  22  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  23  */
  24
  25 /**
  26  * \file common_x86.c
  27  *
  28  * Check CPU capabilities & initialize optimized funtions for this particular
  29  * processor.
  30  *
  31  * Changed by Andre Werthmann for using the new SSE functions.
  32  *
  33  * \author Holger Waechtler <holger@akaflieg.extern.tu-berlin.de>
  34  * \author Andre Werthmann <wertmann@cs.uni-potsdam.de>
  35  */
  36
  37 /* XXX these includes should probably go into imports.h or glheader.h */
  38 #if defined(USE_SSE_ASM) && defined(__linux__)
  39 #include <signal.h>
  40 #endif
  41 #if defined(USE_SSE_ASM) && defined(__FreeBSD__)
  42 #include <sys/types.h>
  43 #include <sys/sysctl.h>
  44 #endif
  45
  46 #include "common_x86_asm.h"
  47 #include "imports.h"
  48
  49
  50 int _mesa_x86_cpu_features = 0;
  51
  52 /* No reason for this to be public.
  53  */
  54 extern GLuint   _ASMAPI _mesa_x86_has_cpuid(void);
  55 extern void     _ASMAPI _mesa_x86_cpuid(GLuint op, GLuint *reg_eax, GLuint *reg_ebx, GLuint *reg_ecx, GLuint *reg_edx);
  56 extern GLuint   _ASMAPI _mesa_x86_cpuid_eax(GLuint op);
  57 extern GLuint   _ASMAPI _mesa_x86_cpuid_ebx(GLuint op);
  58 extern GLuint   _ASMAPI _mesa_x86_cpuid_ecx(GLuint op);
  59 extern GLuint   _ASMAPI _mesa_x86_cpuid_edx(GLuint op);
  60
  61 static void message( const char *msg )
  62 {
  63    GLboolean debug;
  64 #ifdef DEBUG
  65    debug = GL_TRUE;
  66 #else
  67    if ( _mesa_getenv( "MESA_DEBUG" ) ) {
  68       debug = GL_TRUE;
  69    } else {
  70       debug = GL_FALSE;
  71    }
  72 #endif
  73    if ( debug ) {
  74       fprintf( stderr, "%s", msg );
  75    }
  76 }
  77
  78 #if defined(USE_SSE_ASM)
  79 /*
  80  * We must verify that the Streaming SIMD Extensions are truly supported
  81  * on this processor before we go ahead and hook out the optimized code.
  82  * Unfortunately, the CPUID bit isn't enough, as the OS must set the
  83  * OSFXSR bit in CR4 if it supports the extended FPU save and restore
  84  * required to use SSE.  Unfortunately, we can't just go ahead and read
  85  * this register, as only the kernel can do that.  Similarly, we must
  86  * verify that the OSXMMEXCPT bit in CR4 has been set by the OS,
  87  * signifying that it supports unmasked SIMD FPU exceptions.  If we take
  88  * an unmasked exception and the OS doesn't correctly support them, the
  89  * best we'll get is a SIGILL and the worst we'll get is an infinite
  90  * loop in the signal delivery from the kernel as we can't interact with
  91  * the SIMD FPU state to clear the exception bits.  Either way, this is
  92  * not good.
  93  *
  94  * However, I have been told by Alan Cox that all 2.4 (and later) Linux
  95  * kernels provide full SSE support on all processors that expose SSE via
  96  * the CPUID mechanism.  It just so happens that this is the exact set of
  97  * kernels supported DRI.  Therefore, when building for DRI the funky SSE
  98  * exception test is omitted.
  99  */
 100
 101 extern void _mesa_test_os_sse_support( void );
 102 extern void _mesa_test_os_sse_exception_support( void );
 103
 104 #if defined(__linux__) && defined(_POSIX_SOURCE) && defined(X86_FXSR_MAGIC) \
 105    && !defined(DRI_NEW_INTERFACE_ONLY)
 106 static void sigill_handler( int signal, struct sigcontext sc )
 107 {
 108    message( "SIGILL, " );
 109
 110    /* Both the "xorps %%xmm0,%%xmm0" and "divps %xmm0,%%xmm1"
 111     * instructions are 3 bytes long.  We must increment the instruction
 112     * pointer manually to avoid repeated execution of the offending
 113     * instruction.
 114     *
 115     * If the SIGILL is caused by a divide-by-zero when unmasked
 116     * exceptions aren't supported, the SIMD FPU status and control
 117     * word will be restored at the end of the test, so we don't need
 118     * to worry about doing it here.  Besides, we may not be able to...
 119     */
 120    sc.eip += 3;
 121
 122    _mesa_x86_cpu_features &= ~(X86_FEATURE_XMM);
 123 }
 124
 125 static void sigfpe_handler( int signal, struct sigcontext sc )
 126 {
 127    message( "SIGFPE, " );
 128
 129    if ( sc.fpstate->magic != 0xffff ) {
 130       /* Our signal context has the extended FPU state, so reset the
 131        * divide-by-zero exception mask and clear the divide-by-zero
 132        * exception bit.
 133        */
 134       sc.fpstate->mxcsr |= 0x00000200;
 135       sc.fpstate->mxcsr &= 0xfffffffb;
 136    } else {
 137       /* If we ever get here, we're completely hosed.
 138        */
 139       message( "\n\n" );
 140       _mesa_problem( NULL, "SSE enabling test failed badly!" );
 141    }
 142 }
 143 #endif /* __linux__ && _POSIX_SOURCE && X86_FXSR_MAGIC */
 144
 145 /* If we're running on a processor that can do SSE, let's see if we
 146  * are allowed to or not.  This will catch 2.4.0 or later kernels that
 147  * haven't been configured for a Pentium III but are running on one,
 148  * and RedHat patched 2.2 kernels that have broken exception handling
 149  * support for user space apps that do SSE.
 150  *
 151  * GH: Isn't this just awful?
 152  */
 153 static void check_os_sse_support( void )
 154 {
 155 #if defined(__linux__) && !defined(DRI_NEW_INTERFACE_ONLY)
 156 #if defined(_POSIX_SOURCE) && defined(X86_FXSR_MAGIC)
 157    struct sigaction saved_sigill;
 158    struct sigaction saved_sigfpe;
 159
 160    /* Save the original signal handlers.
 161     */
 162    sigaction( SIGILL, NULL, &saved_sigill );
 163    sigaction( SIGFPE, NULL, &saved_sigfpe );
 164
 165    signal( SIGILL, (void (*)(int))sigill_handler );
 166    signal( SIGFPE, (void (*)(int))sigfpe_handler );
 167
 168    /* Emulate test for OSFXSR in CR4.  The OS will set this bit if it
 169     * supports the extended FPU save and restore required for SSE.  If
 170     * we execute an SSE instruction on a PIII and get a SIGILL, the OS
 171     * doesn't support Streaming SIMD Exceptions, even if the processor
 172     * does.
 173     */
 174    if ( cpu_has_xmm ) {
 175       message( "Testing OS support for SSE... " );
 176
 177       _mesa_test_os_sse_support();
 178
 179       if ( cpu_has_xmm ) {
 180          message( "yes.\n" );
 181       } else {
 182          message( "no!\n" );
 183       }
 184    }
 185
 186    /* Emulate test for OSXMMEXCPT in CR4.  The OS will set this bit if
 187     * it supports unmasked SIMD FPU exceptions.  If we unmask the
 188     * exceptions, do a SIMD divide-by-zero and get a SIGILL, the OS
 189     * doesn't support unmasked SIMD FPU exceptions.  If we get a SIGFPE
 190     * as expected, we're okay but we need to clean up after it.
 191     *
 192     * Are we being too stringent in our requirement that the OS support
 193     * unmasked exceptions?  Certain RedHat 2.2 kernels enable SSE by
 194     * setting CR4.OSFXSR but don't support unmasked exceptions.  Win98
 195     * doesn't even support them.  We at least know the user-space SSE
 196     * support is good in kernels that do support unmasked exceptions,
 197     * and therefore to be safe I'm going to leave this test in here.
 198     */
 199    if ( cpu_has_xmm ) {
 200       message( "Testing OS support for SSE unmasked exceptions... " );
 201
 202       _mesa_test_os_sse_exception_support();
 203
 204       if ( cpu_has_xmm ) {
 205          message( "yes.\n" );
 206       } else {
 207          message( "no!\n" );
 208       }
 209    }
 210
 211    /* Restore the original signal handlers.
 212     */
 213    sigaction( SIGILL, &saved_sigill, NULL );
 214    sigaction( SIGFPE, &saved_sigfpe, NULL );
 215
 216    /* If we've gotten to here and the XMM CPUID bit is still set, we're
 217     * safe to go ahead and hook out the SSE code throughout Mesa.
 218     */
 219    if ( cpu_has_xmm ) {
 220       message( "Tests of OS support for SSE passed.\n" );
 221    } else {
 222       message( "Tests of OS support for SSE failed!\n" );
 223    }
 224 #else
 225    /* We can't use POSIX signal handling to test the availability of
 226     * SSE, so we disable it by default.
 227     */
 228    message( "Cannot test OS support for SSE, disabling to be safe.\n" );
 229    _mesa_x86_cpu_features &= ~(X86_FEATURE_XMM);
 230 #endif /* _POSIX_SOURCE && X86_FXSR_MAGIC */
 231 #elif defined(__FreeBSD__)
 232    {
 233       int ret, enabled;
 234       unsigned int len;
 235       len = sizeof(enabled);
 236       ret = sysctlbyname("hw.instruction_sse", &enabled, &len, NULL, 0);
 237       if (ret || !enabled)
 238          _mesa_x86_cpu_features &= ~(X86_FEATURE_XMM);
 239    }
 240 #else
 241    /* Do nothing on other platforms for now.
 242     */
 243    message( "Not testing OS support for SSE, leaving enabled.\n" );
 244 #endif /* __linux__ */
 245 }
 246
 247 #endif /* USE_SSE_ASM */
 248
 249
 250 void _mesa_init_all_x86_transform_asm( void )
 251 {
 252    (void) message; /* silence warning */
 253 #ifdef USE_X86_ASM
 254    _mesa_x86_cpu_features = 0;
 255
 256    if (!_mesa_x86_has_cpuid()) {
 257        message("CPUID not detected");
 258    }
 259    else {
 260        GLuint cpu_features;
 261        GLuint cpu_ext_features;
 262        GLuint cpu_ext_info;
 263        char cpu_vendor[13];
 264        GLuint result;
 265
 266        /* get vendor name */
 267        _mesa_x86_cpuid(0, &result, (GLuint *)(cpu_vendor + 0), (GLuint *)(cpu_vendor + 8), (GLuint *)(cpu_vendor + 4));
 268        cpu_vendor[12] = '\0';
 269
 270        message("cpu vendor: ");
 271        message(cpu_vendor);
 272        message("\n");
 273
 274        /* get cpu features */
 275        cpu_features = _mesa_x86_cpuid_edx(1);
 276
 277        if (cpu_features & X86_CPU_FPU)
 278            _mesa_x86_cpu_features |= X86_FEATURE_FPU;
 279        if (cpu_features & X86_CPU_CMOV)
 280            _mesa_x86_cpu_features |= X86_FEATURE_CMOV;
 281
 282 #ifdef USE_MMX_ASM
 283        if (cpu_features & X86_CPU_MMX)
 284            _mesa_x86_cpu_features |= X86_FEATURE_MMX;
 285 #endif
 286
 287 #ifdef USE_SSE_ASM
 288        if (cpu_features & X86_CPU_XMM)
 289            _mesa_x86_cpu_features |= X86_FEATURE_XMM;
 290        if (cpu_features & X86_CPU_XMM2)
 291            _mesa_x86_cpu_features |= X86_FEATURE_XMM2;
 292 #endif
 293
 294        /* query extended cpu features */
 295        if ((cpu_ext_info = _mesa_x86_cpuid_eax(0x80000000)) > 0x80000000) {
 296            if (cpu_ext_info >= 0x80000001) {
 297
 298                cpu_ext_features = _mesa_x86_cpuid_edx(0x80000001);
 299
 300                if (cpu_features & X86_CPU_MMX) {
 301
 302 #ifdef USE_3DNOW_ASM
 303                    if (cpu_ext_features & X86_CPUEXT_3DNOW)
 304                        _mesa_x86_cpu_features |= X86_FEATURE_3DNOW;
 305                    if (cpu_ext_features & X86_CPUEXT_3DNOW_EXT)
 306                        _mesa_x86_cpu_features |= X86_FEATURE_3DNOWEXT;
 307 #endif
 308
 309 #ifdef USE_MMX_ASM
 310                    if (cpu_ext_features & X86_CPUEXT_MMX_EXT)
 311                        _mesa_x86_cpu_features |= X86_FEATURE_MMXEXT;
 312 #endif
 313                }
 314            }
 315
 316            /* query cpu name */
 317            if (cpu_ext_info >= 0x80000002) {
 318                GLuint ofs;
 319                char cpu_name[49];
 320                for (ofs = 0; ofs < 3; ofs++)
 321                    _mesa_x86_cpuid(0x80000002+ofs, (GLuint *)(cpu_name + (16*ofs)+0), (GLuint *)(cpu_name + (16*ofs)+4), (GLuint *)(cpu_name + (16*ofs)+8), (GLuint *)(cpu_name + (16*ofs)+12));
 322                cpu_name[48] = '\0'; /* the name should be NULL terminated, but just to be sure */
 323
 324                message("cpu name: ");
 325                message(cpu_name);
 326                message("\n");
 327            }
 328        }
 329
 330    }
 331
 332    if ( _mesa_getenv( "MESA_NO_ASM" ) ) {
 333       _mesa_x86_cpu_features = 0;
 334    }
 335
 336    if ( _mesa_x86_cpu_features ) {
 337       _mesa_init_x86_transform_asm();
 338    }
 339
 340 #ifdef USE_MMX_ASM
 341    if ( cpu_has_mmx ) {
 342       if ( _mesa_getenv( "MESA_NO_MMX" ) == 0 ) {
 343          message( "MMX cpu detected.\n" );
 344       } else {
 345          _mesa_x86_cpu_features &= ~(X86_FEATURE_MMX);
 346       }
 347    }
 348 #endif
 349
 350 #ifdef USE_3DNOW_ASM
 351    if ( cpu_has_3dnow ) {
 352       if ( _mesa_getenv( "MESA_NO_3DNOW" ) == 0 ) {
 353          message( "3DNow! cpu detected.\n" );
 354          _mesa_init_3dnow_transform_asm();
 355       } else {
 356          _mesa_x86_cpu_features &= ~(X86_FEATURE_3DNOW);
 357       }
 358    }
 359 #endif
 360
 361 #ifdef USE_SSE_ASM
 362    if ( cpu_has_xmm && _mesa_getenv( "MESA_FORCE_SSE" ) == 0 ) {
 363       check_os_sse_support();
 364    }
 365    if ( cpu_has_xmm ) {
 366       if (_mesa_getenv( "MESA_NO_SSE" ) == 0 ) {
 367          message( "SSE cpu detected.\n" );
 368          _mesa_init_sse_transform_asm();
 369       } else {
 370           message( "SSE cpu detected, but switched off by user.\n" );
 371          _mesa_x86_cpu_features &= ~(X86_FEATURE_XMM);
 372       }
 373    }
 374 #endif
 375 #endif
 376 }
 377