1 /* 2 * This file and its contents are supplied under the terms of the 3 * Common Development and Distribution License ("CDDL"), version 1.0. 4 * You may only use this file in accordance with the terms of version 5 * 1.0 of the CDDL. 6 * 7 * A full copy of the text of the CDDL should have accompanied this 8 * source. A copy of the CDDL is also available via the Internet at 9 * http://www.illumos.org/license/CDDL. 10 */ 11 12 /* 13 * Copyright 2023 Oxide Computer Company 14 */ 15 16 /* 17 * This is a program that is meant to be used as a target for libproc and mdb. 18 * It uses a CLI-based seed and sets its FPU to a set of known values. After 19 * that, we call a function that can be used as a no-op target to dump the FPU 20 * state, attempting to minimize the number of instructions inbetween 21 * operations. We use the 'yield(2)' system call and library function in libc 22 * for that as it's something that'll not really do much and it is very unlikely 23 * the compiler will use the FPU between function calls. 24 */ 25 26 #include <err.h> 27 #include <stdlib.h> 28 #include <unistd.h> 29 #include <errno.h> 30 31 #include "xsave_util.h" 32 33 static xsu_fpu_t fpu; 34 35 int 36 main(int argc, char *argv[]) 37 { 38 uint32_t hwsup; 39 char *eptr; 40 unsigned long ul; 41 42 if (argc != 2) { 43 errx(EXIT_FAILURE, "missing required seed"); 44 } 45 46 errno = 0; 47 ul = strtoul(argv[1], &eptr, 0); 48 if (errno != 0 || *eptr != '\0') { 49 errx(EXIT_FAILURE, "seed value is bad: %s", argv[3]); 50 } 51 52 hwsup = xsu_hwsupport(); 53 xsu_fill(&fpu, hwsup, (uint32_t)ul); 54 xsu_setfpu(&fpu, hwsup); 55 56 yield(); 57 return (EXIT_SUCCESS); 58 } 59