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kernel_start.cpp
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51 lines (41 loc) · 1.48 KB
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// This file is a part of the IncludeOS unikernel - www.includeos.org
//
// Copyright 2015-2016 Oslo and Akershus University College of Applied Sciences
// and Alfred Bratterud
//
// 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.
#include <kernel/os.hpp>
extern "C" void _start() __attribute__((visibility("hidden"))) __attribute__ ((noreturn));
extern "C" void _init_c_runtime();
extern "C" void _init_syscalls();
// enables Streaming SIMD Extensions
static void enableSSE(void)
{
asm ("mov %cr0, %eax");
asm ("and $0xFFFB,%ax");
asm ("or $0x2, %ax");
asm ("mov %eax, %cr0");
asm ("mov %cr4, %eax");
asm ("or $0x600,%ax");
asm ("mov %eax, %cr4");
}
extern "C" void kernel_start(uintptr_t magic, uintptr_t addr) {
// enable SSE extensions bitmask in CR4 register
enableSSE();
// Initialize system calls
_init_syscalls();
// Initialize stack-unwinder, call global constructors etc.
_init_c_runtime();
// Initialize OS including devices
OS::start(magic, addr);
}