diff options
Diffstat (limited to 'i386/i386/fpu.c')
| -rw-r--r-- | i386/i386/fpu.c | 94 |
1 files changed, 45 insertions, 49 deletions
diff --git a/i386/i386/fpu.c b/i386/i386/fpu.c index 03f43f9d..365187ee 100644 --- a/i386/i386/fpu.c +++ b/i386/i386/fpu.c @@ -69,13 +69,20 @@ #define ASSERT_IPL(L) #endif -int fp_kind = FP_387; /* 80387 present */ +int fp_kind = FP_387; /* 80387 present */ enum fp_save_kind fp_save_kind = FP_FNSAVE; /* Which instruction we use to save/restore FPU state */ -uint64_t fp_xsave_support; /* Bitmap of supported XSAVE save areas */ -unsigned fp_xsave_size = sizeof(struct i386_fpsave_state); +uint64_t fp_xsave_support; /* Bitmap of supported XSAVE save areas */ +unsigned fp_xsave_size = sizeof(struct i386_fpsave_state); +struct i386_fpsave_state *fp_default_state; struct kmem_cache ifps_cache; /* cache for FPU save area */ static unsigned long mxcsr_feature_mask = 0xffffffff; /* Always AND user-provided mxcsr with this security mask */ +/* Default FPU configuration */ +#define MXCSR_DEFAULT 0x1f80 +#define CWD_DEFAULT ((0x037f \ + & ~(FPC_IM|FPC_ZM|FPC_OM|FPC_PC)) \ + | (FPC_PC_64|FPC_IC_AFF)) + #if NCPUS == 1 volatile thread_t fp_thread = THREAD_NULL; /* thread whose state is in FPU */ @@ -239,6 +246,33 @@ fpu_module_init(void) fp_xsave_size, alignof(struct i386_fpsave_state), NULL, 0); + + fp_default_state = (struct i386_fpsave_state *) kmem_cache_alloc(&ifps_cache); + memset(fp_default_state, 0, fp_xsave_size); + + switch (fp_save_kind) { + case FP_XSAVEC: + case FP_XSAVES: + /* XRSTORS requires compact format, a bit faster anyway */ + fp_default_state->xfp_save_state.header.xcomp_bv = XSAVE_XCOMP_BV_COMPACT; + /* Fallthrough */ + case FP_XSAVE: + case FP_XSAVEOPT: + case FP_FXSAVE: + fp_default_state->xfp_save_state.fp_control = CWD_DEFAULT; + fp_default_state->xfp_save_state.fp_status = 0; + fp_default_state->xfp_save_state.fp_tag = 0xffff; /* all empty */ + if (CPU_HAS_FEATURE(CPU_FEATURE_SSE)) + fp_default_state->xfp_save_state.fp_mxcsr = MXCSR_DEFAULT; + break; + case FP_FNSAVE: + fp_default_state->fp_save_state.fp_control = CWD_DEFAULT; + fp_default_state->fp_save_state.fp_status = 0; + fp_default_state->fp_save_state.fp_tag = 0xffff; /* all empty */ + break; + } + + fp_default_state->fp_valid = TRUE; } /* @@ -534,14 +568,7 @@ ASSERT_IPL(SPL0); } /* - * Initialize FPU. - * - * Raise exceptions for: - * invalid operation - * divide by zero - * overflow - * - * Use 64-bit precision. + * Initialize FPU for an already-running thread. */ static void fpinit(thread_t thread) { @@ -549,24 +576,11 @@ static void fpinit(thread_t thread) ASSERT_IPL(SPL0); clear_ts(); - fninit(); - if (thread->pcb->init_control) { - control = thread->pcb->init_control; - } - else - { - fnstcw(&control); - control &= ~(FPC_PC|FPC_RC); /* Clear precision & rounding control */ - control |= (FPC_PC_64 | /* Set precision */ - FPC_RC_RN | /* round-to-nearest */ - FPC_ZE | /* Suppress zero-divide */ - FPC_OE | /* and overflow */ - FPC_UE | /* underflow */ - FPC_IE | /* Allow NaNQs and +-INF */ - FPC_DE | /* Allow denorms as operands */ - FPC_PE); /* No trap for precision loss */ - } - fldcw(control); + fpu_rstor(fp_default_state); + + control = thread->pcb->init_control; + if (control) + fldcw(control); } /* @@ -845,7 +859,7 @@ ASSERT_IPL(SPL0); ifps = pcb->ims.ifps; if (ifps == 0) { ifps = (struct i386_fpsave_state *) kmem_cache_alloc(&ifps_cache); - memset(ifps, 0, fp_xsave_size); + memcpy(ifps, fp_default_state, fp_xsave_size); pcb->ims.ifps = ifps; fpinit(thread); #if 1 @@ -893,26 +907,8 @@ fp_state_alloc(void) struct i386_fpsave_state *ifps; ifps = (struct i386_fpsave_state *)kmem_cache_alloc(&ifps_cache); - memset(ifps, 0, fp_xsave_size); + memcpy(ifps, fp_default_state, fp_xsave_size); pcb->ims.ifps = ifps; - - ifps->fp_valid = TRUE; - - if (fp_save_kind != FP_FNSAVE) { - ifps->xfp_save_state.fp_control = (0x037f - & ~(FPC_IM|FPC_ZM|FPC_OM|FPC_PC)) - | (FPC_PC_64|FPC_IC_AFF); - ifps->xfp_save_state.fp_status = 0; - ifps->xfp_save_state.fp_tag = 0xffff; /* all empty */ - if (CPU_HAS_FEATURE(CPU_FEATURE_SSE)) - ifps->xfp_save_state.fp_mxcsr = 0x1f80; - } else { - ifps->fp_save_state.fp_control = (0x037f - & ~(FPC_IM|FPC_ZM|FPC_OM|FPC_PC)) - | (FPC_PC_64|FPC_IC_AFF); - ifps->fp_save_state.fp_status = 0; - ifps->fp_save_state.fp_tag = 0xffff; /* all empty */ - } } #if (defined(AT386) || defined(ATX86_64)) && !defined(MACH_XEN) |