1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause 3 * 4 * Copyright (c) 2020 Val Packett <val@packett.cool> 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND 16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE 19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 25 * SUCH DAMAGE. 26 */ 27 28 #include <sys/types.h> 29 #include <sys/param.h> 30 #include <sys/proc.h> 31 #include <sys/kernel.h> 32 33 #include <linux/compat.h> 34 #include <linux/sched.h> 35 36 #include <asm/fpu/api.h> 37 38 #if defined(__aarch64__) || defined(__arm__) || defined(__amd64__) || \ 39 defined(__i386__) || defined(__powerpc64__) 40 41 #include <machine/fpu.h> 42 43 /* 44 * Technically the Linux API isn't supposed to allow nesting sections 45 * either, but currently used versions of GPU drivers rely on nesting 46 * working, so we only enter the section on the outermost level. 47 */ 48 49 void 50 lkpi_kernel_fpu_begin(void) 51 { 52 if ((current->fpu_ctx_level)++ == 0) 53 fpu_kern_enter(curthread, NULL, FPU_KERN_NOCTX); 54 } 55 56 void 57 lkpi_kernel_fpu_end(void) 58 { 59 if (--(current->fpu_ctx_level) == 0) 60 fpu_kern_leave(curthread, NULL); 61 } 62 63 void 64 lkpi_fpu_safe_exec(fpu_safe_exec_cb_t func, void *ctx) 65 { 66 unsigned int save_fpu_level; 67 68 save_fpu_level = 69 __current_unallocated(curthread) ? 0 : current->fpu_ctx_level; 70 if (__predict_false(save_fpu_level != 0)) { 71 current->fpu_ctx_level = 1; 72 kernel_fpu_end(); 73 } 74 func(ctx); 75 if (__predict_false(save_fpu_level != 0)) { 76 kernel_fpu_begin(); 77 current->fpu_ctx_level = save_fpu_level; 78 } 79 } 80 81 #else 82 83 void 84 lkpi_kernel_fpu_begin(void) 85 { 86 } 87 88 void 89 lkpi_kernel_fpu_end(void) 90 { 91 } 92 93 void 94 lkpi_fpu_safe_exec(fpu_safe_exec_cb_t func, void *ctx) 95 { 96 func(ctx); 97 } 98 99 #endif 100