diff options
Diffstat (limited to 'src/mesa')
| -rw-r--r-- | src/mesa/x86/common_x86.c | 146 |
1 files changed, 6 insertions, 140 deletions
diff --git a/src/mesa/x86/common_x86.c b/src/mesa/x86/common_x86.c index 37a434596a..889b40a89f 100644 --- a/src/mesa/x86/common_x86.c +++ b/src/mesa/x86/common_x86.c @@ -36,7 +36,7 @@ /* XXX these includes should probably go into imports.h or glheader.h */ #if defined(USE_SSE_ASM) && defined(__linux__) -#include <signal.h> +#include <linux/version.h> #endif #if defined(USE_SSE_ASM) && defined(__FreeBSD__) #include <sys/types.h> @@ -63,69 +63,14 @@ extern GLuint _ASMAPI _mesa_x86_cpuid_edx(GLuint op); /* * 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. * * However, I have been told by Alan Cox that all 2.4 (and later) Linux * kernels provide full SSE support on all processors that expose SSE via - * the CPUID mechanism. It just so happens that this is the exact set of - * kernels supported DRI. Therefore, when building for DRI the funky SSE - * exception test is omitted. + * the CPUID mechanism. */ - 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) \ - && !defined(IN_DRI_DRIVER) -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 defined(WIN32) #ifndef STATUS_FLOAT_MULTIPLE_TRAPS # define STATUS_FLOAT_MULTIPLE_TRAPS (0xC00002B5L) @@ -157,92 +102,13 @@ static LONG WINAPI ExceptionFilter(LPEXCEPTION_POINTERS exp) #endif /* WIN32 */ -/* 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__) && !defined(IN_DRI_DRIVER) -#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 ) { - _mesa_debug(NULL, "Testing OS support for SSE...\n"); - - _mesa_test_os_sse_support(); - - if ( cpu_has_xmm ) { - _mesa_debug(NULL, "Yes\n"); - } else { - _mesa_debug(NULL, "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 ) { - _mesa_debug(NULL, "Testing OS support for SSE unmasked exceptions...\n"); - - _mesa_test_os_sse_exception_support(); - - if ( cpu_has_xmm ) { - _mesa_debug(NULL, "Yes.\n"); - } else { - _mesa_debug(NULL, "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 ) { - _mesa_debug(NULL, "Tests of OS support for SSE passed.\n"); - } else { - _mesa_debug(NULL, "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. - */ - _mesa_debug(NULL, "Cannot test OS support for SSE, disabling to be safe.\n"); +#if defined(__linux__) +#if LINUX_VERSION_CODE < KERNEL_VERSION(2,4,0) + _mesa_debug(NULL, "Cannot safely enable SSE on pre-2.4 kernels.\n"); _mesa_x86_cpu_features &= ~(X86_FEATURE_XMM); -#endif /* _POSIX_SOURCE && X86_FXSR_MAGIC */ +#endif #elif defined(__FreeBSD__) { int ret, enabled; |