| 0,0 → 1,114 |
|---|
| /* |
| * Copyright (c) 2007 Petr Stepan, Pavel Jancik |
| * 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 arm32 |
| * @{ |
| */ |
| /** @file |
| */ |
| |
| #include <userspace.h> |
| |
| /** Struct to hold general purpose register values */ |
| typedef struct { |
| uint32_t r0; |
| uint32_t r1; |
| uint32_t r2; |
| uint32_t r3; |
| uint32_t r4; |
| uint32_t r5; |
| uint32_t r6; |
| uint32_t r7; |
| uint32_t r8; |
| uint32_t r9; |
| uint32_t r10; |
| uint32_t r11; |
| uint32_t r12; |
| uint32_t sp; |
| uint32_t lr; |
| uint32_t pc; |
| } ustate_t; |
| |
| /** Changes processor mode and jumps to the address specified in the first parameter. |
| * |
| * @param kernel_uarg Userspace settings (entry point, stack, ...). |
| */ |
| void userspace(uspace_arg_t *kernel_uarg) |
| { |
| |
| volatile ustate_t ustate; |
| |
| // set first parameter |
| ustate.r0 = (uintptr_t) kernel_uarg->uspace_uarg; |
| |
| // clear other registers |
| ustate.r1 = ustate.r2 = ustate.r3 = ustate.r4 = |
| ustate.r5 = ustate.r6 = ustate.r7 = ustate.r8 = |
| ustate.r9 = ustate.r10 = ustate.r11 = ustate.r12 = |
| ustate.lr = 0; |
| |
| //set user stack |
| ustate.sp = ((uint32_t)kernel_uarg->uspace_stack) + |
| PAGE_SIZE - sizeof(void*); |
| |
| //set where uspace execution starts |
| ustate.pc = (uintptr_t) kernel_uarg->uspace_entry; |
| |
| //status register in user mode |
| ipl_t cpsr = current_status_reg_read(); |
| cpsr &= ~STATUS_REG_MODE_MASK | USER_MODE; |
| |
| ipl_t tmpsr = (cpsr & ~STATUS_REG_MODE_MASK) | SUPERVISOR_MODE; |
| |
| asm __volatile__ ( |
| // save pointer into ustate struct |
| "mov r0, %0 \n" |
| // save cspr |
| "mov r1, %1 \n" |
| // change mode into any exception mode |
| "msr cpsr_c, %2 \n" |
| // set saved cpsr |
| "msr spsr_c, r1 \n" |
| |
| "mov sp, r0 \n" |
| // replace almost all registers |
| "ldmfd sp!, {r0-r12, sp, lr}^\n" |
| //jump to the usermode |
| "ldmfd sp!, {pc}^" |
| : // no output |
| : "r"(&ustate), "r"(cpsr), "r"(tmpsr) // |
| : "r0","r1" |
| ); |
| |
| // unreachable |
| while(1) ; |
| } |
| |
| |
| /** @} |
| */ |