/* * Copyright 2018, Data61 * Commonwealth Scientific and Industrial Research Organisation (CSIRO) * ABN 41 687 119 230. * * This software may be distributed and modified according to the terms of * the BSD 2-Clause license. Note that NO WARRANTY is provided. * See "LICENSE_BSD2.txt" for details. * * @TAG(DATA61_BSD) */ #pragma once #include #include #include #include // uses the simple extended bootinfo interface to attempt to determine the tsc frequency // returns 0 on failure static inline uint32_t x86_get_tsc_freq_from_simple(simple_t *simple) { // the simple interface is a bit awkward and doesn't give us a way to just get the last 4 // bytes so we have to define some scratch space to get what we want. use a char array instead // of a custom struct so we're not worrying about padding and aliasing etc char buf[sizeof(seL4_BootInfoHeader) + 4]; ssize_t ret = simple_get_extended_bootinfo(simple, SEL4_BOOTINFO_HEADER_X86_TSC_FREQ, buf, sizeof(buf)); if (ret == sizeof(buf)) { uint32_t freq; memcpy(&freq, buf + sizeof(seL4_BootInfoHeader), 4); // convert mhz to hz return freq * MHZ; } return 0; }