/* * Copyright (c) 2005 Ondrej Palkovsky * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * - Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * - Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * - The name of the author may not be used to endorse or promote products * derived from this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ /** @addtogroup kernel_amd64 * @{ */ /** @file */ #include <userspace.h> #include <arch/cpu.h> #include <arch/pm.h> #include <stdbool.h> #include <stdint.h> #include <arch.h> #include <mm/as.h> uintptr_t arch_get_initial_sp(uintptr_t stack_base, uintptr_t stack_size) { return stack_base + stack_size; } /** Enter userspace * * Change CPU protection level to 3, enter userspace. * */ void userspace(uintptr_t pc, uintptr_t sp) { uint64_t rflags = read_rflags(); rflags &= ~RFLAGS_NT; rflags |= RFLAGS_IF; asm volatile ( "pushq %[udata_des]\n" "pushq %[stack_top]\n" "pushq %[rflags]\n" "pushq %[utext_des]\n" "pushq %[entry]\n" /* %rdi is defined to hold pcb_ptr - set it to 0 */ "xorq %%rdi, %%rdi\n" "iretq\n" :: [udata_des] "i" (GDT_SELECTOR(UDATA_DES) | PL_USER), [stack_top] "r" (sp), [rflags] "r" (rflags), [utext_des] "i" (GDT_SELECTOR(UTEXT_DES) | PL_USER), [entry] "r" (pc) ); unreachable(); } /** @} */