| 1 | /*
|
|---|
| 2 | * Copyright (c) 2007 Petr Stepan, Pavel Jancik
|
|---|
| 3 | * All rights reserved.
|
|---|
| 4 | *
|
|---|
| 5 | * Redistribution and use in source and binary forms, with or without
|
|---|
| 6 | * modification, are permitted provided that the following conditions
|
|---|
| 7 | * are met:
|
|---|
| 8 | *
|
|---|
| 9 | * - Redistributions of source code must retain the above copyright
|
|---|
| 10 | * notice, this list of conditions and the following disclaimer.
|
|---|
| 11 | * - Redistributions in binary form must reproduce the above copyright
|
|---|
| 12 | * notice, this list of conditions and the following disclaimer in the
|
|---|
| 13 | * documentation and/or other materials provided with the distribution.
|
|---|
| 14 | * - The name of the author may not be used to endorse or promote products
|
|---|
| 15 | * derived from this software without specific prior written permission.
|
|---|
| 16 | *
|
|---|
| 17 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
|
|---|
| 18 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
|
|---|
| 19 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
|
|---|
| 20 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
|
|---|
| 21 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
|
|---|
| 22 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
|
|---|
| 23 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
|
|---|
| 24 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
|
|---|
| 25 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
|
|---|
| 26 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
|
|---|
| 27 | */
|
|---|
| 28 |
|
|---|
| 29 | /** @addtogroup kernel_arm32
|
|---|
| 30 | * @{
|
|---|
| 31 | */
|
|---|
| 32 | /** @file
|
|---|
| 33 | * @brief Userspace switch.
|
|---|
| 34 | */
|
|---|
| 35 |
|
|---|
| 36 | #include <stdbool.h>
|
|---|
| 37 | #include <userspace.h>
|
|---|
| 38 | #include <arch/ras.h>
|
|---|
| 39 |
|
|---|
| 40 | /** Struct for holding all general purpose registers.
|
|---|
| 41 | *
|
|---|
| 42 | * Used to set registers when going to userspace.
|
|---|
| 43 | */
|
|---|
| 44 | typedef struct {
|
|---|
| 45 | uint32_t r0;
|
|---|
| 46 | uint32_t r1;
|
|---|
| 47 | uint32_t r2;
|
|---|
| 48 | uint32_t r3;
|
|---|
| 49 | uint32_t r4;
|
|---|
| 50 | uint32_t r5;
|
|---|
| 51 | uint32_t r6;
|
|---|
| 52 | uint32_t r7;
|
|---|
| 53 | uint32_t r8;
|
|---|
| 54 | uint32_t r9;
|
|---|
| 55 | uint32_t r10;
|
|---|
| 56 | uint32_t r11;
|
|---|
| 57 | uint32_t r12;
|
|---|
| 58 | uint32_t sp;
|
|---|
| 59 | uint32_t lr;
|
|---|
| 60 | uint32_t pc;
|
|---|
| 61 | } ustate_t;
|
|---|
| 62 |
|
|---|
| 63 | /** Change processor mode
|
|---|
| 64 | *
|
|---|
| 65 | * @param kernel_uarg Userspace settings (entry point, stack, ...).
|
|---|
| 66 | *
|
|---|
| 67 | */
|
|---|
| 68 | void userspace(uspace_arg_t *kernel_uarg)
|
|---|
| 69 | {
|
|---|
| 70 | volatile ustate_t ustate;
|
|---|
| 71 |
|
|---|
| 72 | /* set first parameter */
|
|---|
| 73 | ustate.r0 = (uintptr_t) kernel_uarg->uspace_uarg;
|
|---|
| 74 |
|
|---|
| 75 | /* %r1 is defined to hold pcb_ptr - set it to 0 */
|
|---|
| 76 | ustate.r1 = 0;
|
|---|
| 77 |
|
|---|
| 78 | /* pass the RAS page address in %r2 */
|
|---|
| 79 | ustate.r2 = (uintptr_t) ras_page;
|
|---|
| 80 |
|
|---|
| 81 | /* clear other registers */
|
|---|
| 82 | ustate.r3 = 0;
|
|---|
| 83 | ustate.r4 = 0;
|
|---|
| 84 | ustate.r5 = 0;
|
|---|
| 85 | ustate.r6 = 0;
|
|---|
| 86 | ustate.r7 = 0;
|
|---|
| 87 | ustate.r8 = 0;
|
|---|
| 88 | ustate.r9 = 0;
|
|---|
| 89 | ustate.r10 = 0;
|
|---|
| 90 | ustate.r11 = 0;
|
|---|
| 91 | ustate.r12 = 0;
|
|---|
| 92 | ustate.lr = 0;
|
|---|
| 93 |
|
|---|
| 94 | /* set user stack */
|
|---|
| 95 | ustate.sp = ((uint32_t) kernel_uarg->uspace_stack) +
|
|---|
| 96 | kernel_uarg->uspace_stack_size;
|
|---|
| 97 |
|
|---|
| 98 | /* set where uspace execution starts */
|
|---|
| 99 | ustate.pc = (uintptr_t) kernel_uarg->uspace_entry;
|
|---|
| 100 |
|
|---|
| 101 | /* status register in user mode */
|
|---|
| 102 | ipl_t user_mode = current_status_reg_read() &
|
|---|
| 103 | (~STATUS_REG_MODE_MASK | USER_MODE);
|
|---|
| 104 |
|
|---|
| 105 | /* set user mode, set registers, jump */
|
|---|
| 106 | asm volatile (
|
|---|
| 107 | "mov sp, %[ustate]\n"
|
|---|
| 108 | "msr spsr_c, %[user_mode]\n"
|
|---|
| 109 | "ldmfd sp, {r0-r12, sp, lr}^\n"
|
|---|
| 110 | "nop\n" /* Cannot access sp immediately after ldm(2) */
|
|---|
| 111 | "add sp, sp, #(15*4)\n"
|
|---|
| 112 | "ldmfd sp!, {pc}^\n"
|
|---|
| 113 | :: [ustate] "r" (&ustate), [user_mode] "r" (user_mode)
|
|---|
| 114 | );
|
|---|
| 115 |
|
|---|
| 116 | /* unreachable */
|
|---|
| 117 | while (true)
|
|---|
| 118 | ;
|
|---|
| 119 | }
|
|---|
| 120 |
|
|---|
| 121 | /** @}
|
|---|
| 122 | */
|
|---|
