/* * Copyright (c) 2005 Jakub Jermar * 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_ia32 * @{ */ /** @file */ #include <userspace.h> #include <arch/pm.h> #include <stdbool.h> #include <stdint.h> #include <arch.h> #include <mm/as.h> #include <arch/cpu.h> #include <arch/asm.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) { uint32_t eflags = read_eflags(); asm volatile ( /* Set up GS register (virtual register segment) */ "movl %[vreg_des], %%gs\n" "pushl %[udata_des]\n" "pushl %[stack_top]\n" "pushl %[eflags]\n" "pushl %[utext_des]\n" "pushl %[entry]\n" /* %edi is defined to hold pcb_ptr - set it to 0 */ "xorl %%edi, %%edi\n" "iret\n" : : [eflags_mask] "i" (~EFLAGS_NT), [udata_des] "i" (GDT_SELECTOR(UDATA_DES) | PL_USER), [stack_top] "r" (sp), [eflags] "r" ((eflags & ~(EFLAGS_NT)) | EFLAGS_IF), [utext_des] "i" (GDT_SELECTOR(UTEXT_DES) | PL_USER), [entry] "r" (pc), [vreg_des] "r" (GDT_SELECTOR(VREG_DES)) : "eax"); unreachable(); } /** @} */