/* $XFree86: xc/extras/Mesa/src/X86/common_x86.c,v 1.14 2003/10/22 15:44:42 tsi Exp $ */ /* * Mesa 3-D graphics library * Version: 5.0 * * Copyright (C) 1999-2002 Brian Paul All Rights Reserved. * * Permission is hereby granted, free of charge, to any person obtaining a * copy of this software and associated documentation files (the "Software"), * to deal in the Software without restriction, including without limitation * the rights to use, copy, modify, merge, publish, distribute, sublicense, * and/or sell copies of the Software, and to permit persons to whom the * Software is furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice shall be included * in all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL * BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */ /* * Check CPU capabilities & initialize optimized funtions for this particular * processor. * * Written by Holger Waechtler <holger@akaflieg.extern.tu-berlin.de> * Changed by Andre Werthmann <wertmann@cs.uni-potsdam.de> for using the * new SSE functions. */ #include <stdlib.h> #include <stdio.h> #if defined(USE_SSE_ASM) && defined(__linux__) #include <signal.h> #endif #if defined(USE_SSE_ASM) && defined(__FreeBSD__) #include <sys/types.h> #include <sys/sysctl.h> #endif #include "context.h" #include "common_x86_asm.h" #include "imports.h" int _mesa_x86_cpu_features = 0; /* No reason for this to be public. */ extern int _mesa_identify_x86_cpu_features( void ); static void message( const char *msg ) { GLboolean debug; #ifdef DEBUG debug = GL_TRUE; #else if ( getenv( "MESA_DEBUG" ) ) { debug = GL_TRUE; } else { debug = GL_FALSE; } #endif if ( debug ) { fprintf( stderr, "%s", msg ); } } #if defined(USE_SSE_ASM) /* * We must verify that the Streaming SIMD Extensions are truly supported * on this processor before we go ahead and hook out the optimized code. * Unfortunately, the CPUID bit isn't enough, as the OS must set the * OSFXSR bit in CR4 if it supports the extended FPU save and restore * required to use SSE. Unfortunately, we can't just go ahead and read * this register, as only the kernel can do that. Similarly, we must * verify that the OSXMMEXCPT bit in CR4 has been set by the OS, * signifying that it supports unmasked SIMD FPU exceptions. If we take * an unmasked exception and the OS doesn't correctly support them, the * best we'll get is a SIGILL and the worst we'll get is an infinite * loop in the signal delivery from the kernel as we can't interact with * the SIMD FPU state to clear the exception bits. Either way, this is * not good. */ extern void _mesa_test_os_sse_support( void ); extern void _mesa_test_os_sse_exception_support( void ); #if defined(__linux__) && defined(_POSIX_SOURCE) && defined(X86_FXSR_MAGIC) static void sigill_handler( int signal, struct sigcontext sc ) { message( "SIGILL, " ); /* Both the "xorps %%xmm0,%%xmm0" and "divps %xmm0,%%xmm1" * instructions are 3 bytes long. We must increment the instruction * pointer manually to avoid repeated execution of the offending * instruction. * * If the SIGILL is caused by a divide-by-zero when unmasked * exceptions aren't supported, the SIMD FPU status and control * word will be restored at the end of the test, so we don't need * to worry about doing it here. Besides, we may not be able to... */ sc.eip += 3; _mesa_x86_cpu_features &= ~(X86_FEATURE_XMM); } static void sigfpe_handler( int signal, struct sigcontext sc ) { message( "SIGFPE, " ); if ( sc.fpstate->magic != 0xffff ) { /* Our signal context has the extended FPU state, so reset the * divide-by-zero exception mask and clear the divide-by-zero * exception bit. */ sc.fpstate->mxcsr |= 0x00000200; sc.fpstate->mxcsr &= 0xfffffffb; } else { /* If we ever get here, we're completely hosed. */ message( "\n\n" ); _mesa_problem( NULL, "SSE enabling test failed badly!" ); } } #endif /* __linux__ && _POSIX_SOURCE && X86_FXSR_MAGIC */ /* If we're running on a processor that can do SSE, let's see if we * are allowed to or not. This will catch 2.4.0 or later kernels that * haven't been configured for a Pentium III but are running on one, * and RedHat patched 2.2 kernels that have broken exception handling * support for user space apps that do SSE. * * GH: Isn't this just awful? */ static void check_os_sse_support( void ) { #if defined(__linux__) #if defined(_POSIX_SOURCE) && defined(X86_FXSR_MAGIC) struct sigaction saved_sigill; struct sigaction saved_sigfpe; /* Save the original signal handlers. */ sigaction( SIGILL, NULL, &saved_sigill ); sigaction( SIGFPE, NULL, &saved_sigfpe ); signal( SIGILL, (void (*)(int))sigill_handler ); signal( SIGFPE, (void (*)(int))sigfpe_handler ); /* Emulate test for OSFXSR in CR4. The OS will set this bit if it * supports the extended FPU save and restore required for SSE. If * we execute an SSE instruction on a PIII and get a SIGILL, the OS * doesn't support Streaming SIMD Exceptions, even if the processor * does. */ if ( cpu_has_xmm ) { message( "Testing OS support for SSE... " ); _mesa_test_os_sse_support(); if ( cpu_has_xmm ) { message( "yes.\n" ); } else { message( "no!\n" ); } } /* Emulate test for OSXMMEXCPT in CR4. The OS will set this bit if * it supports unmasked SIMD FPU exceptions. If we unmask the * exceptions, do a SIMD divide-by-zero and get a SIGILL, the OS * doesn't support unmasked SIMD FPU exceptions. If we get a SIGFPE * as expected, we're okay but we need to clean up after it. * * Are we being too stringent in our requirement that the OS support * unmasked exceptions? Certain RedHat 2.2 kernels enable SSE by * setting CR4.OSFXSR but don't support unmasked exceptions. Win98 * doesn't even support them. We at least know the user-space SSE * support is good in kernels that do support unmasked exceptions, * and therefore to be safe I'm going to leave this test in here. */ if ( cpu_has_xmm ) { message( "Testing OS support for SSE unmasked exceptions... " ); _mesa_test_os_sse_exception_support(); if ( cpu_has_xmm ) { message( "yes.\n" ); } else { message( "no!\n" ); } } /* Restore the original signal handlers. */ sigaction( SIGILL, &saved_sigill, NULL ); sigaction( SIGFPE, &saved_sigfpe, NULL ); /* If we've gotten to here and the XMM CPUID bit is still set, we're * safe to go ahead and hook out the SSE code throughout Mesa. */ if ( cpu_has_xmm ) { message( "Tests of OS support for SSE passed.\n" ); } else { message( "Tests of OS support for SSE failed!\n" ); } #else /* We can't use POSIX signal handling to test the availability of * SSE, so we disable it by default. */ message( "Cannot test OS support for SSE, disabling to be safe.\n" ); _mesa_x86_cpu_features &= ~(X86_FEATURE_XMM); #endif /* _POSIX_SOURCE && X86_FXSR_MAGIC */ #elif defined(__FreeBSD__) { int ret, len, enabled; len = sizeof(enabled); ret = sysctlbyname("hw.instruction_sse", &enabled, &len, NULL, 0); if (ret || !enabled) _mesa_x86_cpu_features &= ~(X86_FEATURE_XMM); } #else /* Do nothing on other platforms for now. */ message( "Not testing OS support for SSE, leaving enabled.\n" ); #endif /* __linux__ */ } #endif /* USE_SSE_ASM */ void _mesa_init_all_x86_transform_asm( void ) { (void) message; /* silence warning */ #ifdef USE_X86_ASM _mesa_x86_cpu_features = _mesa_identify_x86_cpu_features(); if ( getenv( "MESA_NO_ASM" ) ) { _mesa_x86_cpu_features = 0; } if ( _mesa_x86_cpu_features ) { _mesa_init_x86_transform_asm(); } #ifdef USE_MMX_ASM if ( cpu_has_mmx ) { if ( getenv( "MESA_NO_MMX" ) == 0 ) { message( "MMX cpu detected.\n" ); } else { _mesa_x86_cpu_features &= ~(X86_FEATURE_MMX); } } #endif #ifdef USE_3DNOW_ASM if ( cpu_has_3dnow ) { if ( getenv( "MESA_NO_3DNOW" ) == 0 ) { message( "3DNow! cpu detected.\n" ); _mesa_init_3dnow_transform_asm(); } else { _mesa_x86_cpu_features &= ~(X86_FEATURE_3DNOW); } } #endif #ifdef USE_SSE_ASM if ( cpu_has_xmm && getenv( "MESA_FORCE_SSE" ) == 0 ) { check_os_sse_support(); } if ( cpu_has_xmm ) { if ( getenv( "MESA_NO_SSE" ) == 0 ) { message( "SSE cpu detected.\n" ); _mesa_init_sse_transform_asm(); } else { _mesa_x86_cpu_features &= ~(X86_FEATURE_XMM); } } #endif #endif }