141 lines
3.9 KiB
C
141 lines
3.9 KiB
C
/*
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* Copyright (c) 2010, Stefan Lankes, RWTH Aachen University
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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* * Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* * Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* * Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this
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* software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY
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* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
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* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <eduos/stddef.h>
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#include <eduos/stdio.h>
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#include <eduos/string.h>
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#include <eduos/time.h>
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#include <eduos/processor.h>
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#include <eduos/tasks.h>
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cpu_info_t cpu_info = { 0, 0 };
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static uint32_t cpu_freq = 0;
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static void default_mb(void)
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{
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asm volatile ("lock; addl $0,0(%%esp)" ::: "memory", "cc");
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}
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func_memory_barrier mb = default_mb;
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func_memory_barrier rmb = default_mb;
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func_memory_barrier wmb = default_mb;
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static void mfence(void) { asm volatile("mfence" ::: "memory"); }
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static void lfence(void) { asm volatile("lfence" ::: "memory"); }
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static void sfence(void) { asm volatile("sfence" ::: "memory"); }
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uint32_t detect_cpu_frequency(void)
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{
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uint64_t start, end, diff;
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uint64_t ticks, old;
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if (BUILTIN_EXPECT(cpu_freq > 0, 0))
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return cpu_freq;
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old = get_clock_tick();
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/* wait for the next time slice */
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while((ticks = get_clock_tick()) - old == 0)
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HALT;
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rmb();
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start = rdtsc();
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/* wait a second to determine the frequency */
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while(get_clock_tick() - ticks < TIMER_FREQ)
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HALT;
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rmb();
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end = rdtsc();
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diff = end > start ? end - start : start - end;
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cpu_freq = (uint32_t) (diff / (uint64_t) 1000000);
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return cpu_freq;
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}
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int cpu_detection(void) {
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uint32_t a, b;
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size_t cr4;
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uint8_t first_time = 0;
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if (!cpu_info.feature1) {
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first_time = 1;
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cpuid(1, &a, &b, &cpu_info.feature2, &cpu_info.feature1);
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}
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cr4 = read_cr4();
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if (has_fxsr())
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cr4 |= 0x200; // set the OSFXSR bit
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if (has_sse())
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cr4 |= 0x400; // set the OSXMMEXCPT bit
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write_cr4(cr4);
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if (first_time && has_sse())
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wmb = sfence;
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if (first_time && has_sse2()) {
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rmb = lfence;
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mb = mfence;
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}
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if (first_time && has_avx())
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kprintf(
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"The CPU owns the Advanced Vector Extensions (AVX). However, eduOS doesn't support AVX!\n");
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if (has_fpu()) {
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if (first_time)
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kputs("Found and initialized FPU!\n");
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asm volatile ("fninit");
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}
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if (first_time && on_hypervisor()) {
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uint32_t c, d;
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char vendor_id[13];
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kprintf("eduOS is running on a hypervisor!\n");
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cpuid(0x40000000, &a, &b, &c, &d);
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memcpy(vendor_id, &b, 4);
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memcpy(vendor_id + 4, &c, 4);
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memcpy(vendor_id + 8, &d, 4);
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vendor_id[12] = '\0';
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kprintf("Hypervisor Vendor Id: %s\n", vendor_id);
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kprintf("Maximum input value for hypervisor: 0x%x\n", a);
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}
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return 0;
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}
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uint32_t get_cpu_frequency(void)
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{
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if (cpu_freq > 0)
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return cpu_freq;
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return detect_cpu_frequency();
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}
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