metalsvm/arch/x86/kernel/processor.c
2011-08-02 15:58:20 +02:00

112 lines
2.5 KiB
C

/*
* Copyright 2010 Stefan Lankes, Chair for Operating Systems,
* RWTH Aachen University
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
* This file is part of MetalSVM.
*/
#include <metalsvm/stddef.h>
#include <metalsvm/stdio.h>
#include <metalsvm/time.h>
#include <metalsvm/processor.h>
#include <metalsvm/tasks.h>
#ifdef CONFIG_ROCKCREEK
#include <asm/RCCE_lib.h>
#endif
cpu_info_t cpu_info = { 0, 0 };
static uint32_t cpu_freq = 0;
int cpu_detection(void)
{
uint32_t a, b, cr4;
cpuid(1, &a, &b, &cpu_info.feature2, &cpu_info.feature1);
cr4 = read_cr4();
if (has_fxsr())
cr4 |= 0x200; // set the OSFXSR bit
if (has_xmm())
cr4 |= 0x400; // set the OSXMMEXCPT bit
write_cr4(cr4);
if (has_avx())
kprintf("The CPU owns the Advanced Vector Extensions (AVX). However, MetalSVM doesn't support AVX!\n");
if (has_fpu())
asm volatile ("fninit");
return 0;
}
uint32_t detect_cpu_frequency(void)
{
#ifdef CONFIG_ROCKCREEK
if (cpu_freq > 0)
return cpu_freq;
cpu_freq = RC_REFCLOCKMHZ;
return cpu_freq;
#else
uint64_t start, end, diff;
uint64_t ticks, old;
if (BUILTIN_EXPECT(cpu_freq > 0, 0))
return cpu_freq;
old = get_clock_tick();
/* wait for the next time slice */
while((ticks = get_clock_tick()) - old == 0)
HALT;
mb();
start = rdtsc();
/* wait a second to determine the frequency */
while(get_clock_tick() - ticks < TIMER_FREQ)
HALT;
mb();
end = rdtsc();
diff = end > start ? end - start : start - end;
cpu_freq = (uint32_t) (diff / (uint64_t) 1000000);
return cpu_freq;
#endif
}
uint32_t get_cpu_frequency(void)
{
if (cpu_freq > 0)
return cpu_freq;
return detect_cpu_frequency();
}
void udelay(uint32_t usecs)
{
uint64_t diff, end, start = rdtsc();
uint64_t deadline = get_cpu_frequency() * usecs;
do {
mb();
end = rdtsc();
diff = end > start ? end - start : start - end;
if ((diff < deadline) && (deadline - diff > 50000))
check_workqueues();
} while(diff < deadline);
}