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2362 | jancik | 1 | /* |
2 | * Copyright (c) 2007 Petr Stepan, Pavel Jancik |
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3 | * All rights reserved. |
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4 | * |
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5 | * Redistribution and use in source and binary forms, with or without |
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6 | * modification, are permitted provided that the following conditions |
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7 | * are met: |
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8 | * |
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9 | * - Redistributions of source code must retain the above copyright |
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10 | * notice, this list of conditions and the following disclaimer. |
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11 | * - Redistributions in binary form must reproduce the above copyright |
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12 | * notice, this list of conditions and the following disclaimer in the |
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13 | * documentation and/or other materials provided with the distribution. |
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14 | * - The name of the author may not be used to endorse or promote products |
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15 | * derived from this software without specific prior written permission. |
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16 | * |
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17 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
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18 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
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19 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
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20 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
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21 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
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22 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
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23 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
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24 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
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25 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
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26 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
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27 | */ |
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28 | |||
29 | /** @addtogroup arm32 |
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30 | * @{ |
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31 | */ |
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32 | /** @file |
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2413 | kebrt | 33 | * @brief Userspace switch. |
2362 | jancik | 34 | */ |
35 | |||
36 | #include <userspace.h> |
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37 | |||
2413 | kebrt | 38 | |
39 | /** Struct for holding all general purpose registers. |
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40 | * |
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41 | * Used to set registers when going to userspace. |
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42 | */ |
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2362 | jancik | 43 | typedef struct { |
44 | uint32_t r0; |
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45 | uint32_t r1; |
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46 | uint32_t r2; |
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47 | uint32_t r3; |
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48 | uint32_t r4; |
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49 | uint32_t r5; |
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50 | uint32_t r6; |
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51 | uint32_t r7; |
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52 | uint32_t r8; |
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53 | uint32_t r9; |
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54 | uint32_t r10; |
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55 | uint32_t r11; |
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56 | uint32_t r12; |
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57 | uint32_t sp; |
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58 | uint32_t lr; |
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59 | uint32_t pc; |
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60 | } ustate_t; |
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61 | |||
2411 | stepan | 62 | |
2362 | jancik | 63 | /** Changes processor mode and jumps to the address specified in the first parameter. |
64 | * |
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65 | * @param kernel_uarg Userspace settings (entry point, stack, ...). |
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66 | */ |
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67 | void userspace(uspace_arg_t *kernel_uarg) |
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68 | { |
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69 | |||
70 | volatile ustate_t ustate; |
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71 | |||
72 | // set first parameter |
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73 | ustate.r0 = (uintptr_t) kernel_uarg->uspace_uarg; |
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74 | |||
75 | // clear other registers |
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76 | ustate.r1 = ustate.r2 = ustate.r3 = ustate.r4 = |
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77 | ustate.r5 = ustate.r6 = ustate.r7 = ustate.r8 = |
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78 | ustate.r9 = ustate.r10 = ustate.r11 = ustate.r12 = |
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79 | ustate.lr = 0; |
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80 | |||
2413 | kebrt | 81 | // set user stack |
82 | ustate.sp = ((uint32_t)kernel_uarg->uspace_stack) + PAGE_SIZE; |
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2362 | jancik | 83 | |
2413 | kebrt | 84 | // set where uspace execution starts |
2362 | jancik | 85 | ustate.pc = (uintptr_t) kernel_uarg->uspace_entry; |
86 | |||
2413 | kebrt | 87 | // status register in user mode |
88 | ipl_t user_mode = current_status_reg_read() & (~STATUS_REG_MODE_MASK | USER_MODE); |
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2362 | jancik | 89 | |
2413 | kebrt | 90 | // set user mode, set registers, jump |
2362 | jancik | 91 | asm __volatile__ ( |
2413 | kebrt | 92 | "mov r0, %0 \n" |
93 | "msr spsr_c, %1 \n" |
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94 | "ldmfd r0!, {r0-r12, sp, lr}^ \n" |
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95 | "ldmfd r0!, {pc}^" |
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96 | |||
97 | : |
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98 | : "r"(&ustate), "r"(user_mode) |
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99 | : "r0", "r1" |
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2362 | jancik | 100 | ); |
101 | |||
102 | // unreachable |
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103 | while(1) ; |
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104 | } |
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105 | |||
106 | |||
107 | /** @} |
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108 | */ |