| 1 | /*
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| 2 | * Copyright (c) 2005 Jakub Jermar
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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 |
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| 29 | /** @addtogroup kernel_ia32
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| 30 | * @{
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| 31 | */
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| 32 | /** @file
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| 33 | */
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| 34 |
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| 35 | #include <userspace.h>
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| 36 | #include <arch/pm.h>
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| 37 | #include <stdbool.h>
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| 38 | #include <stdint.h>
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| 39 | #include <arch.h>
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| 40 | #include <abi/proc/uarg.h>
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| 41 | #include <mm/as.h>
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| 42 | #include <arch/cpu.h>
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| 43 | #include <arch/asm.h>
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| 44 |
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| 45 | /** Enter userspace
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| 46 | *
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| 47 | * Change CPU protection level to 3, enter userspace.
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| 48 | *
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| 49 | */
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| 50 | void userspace(uspace_arg_t *kernel_uarg)
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| 51 | {
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| 52 | uint32_t eflags = read_eflags();
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| 53 |
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| 54 | asm volatile (
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| 55 | /* Set up GS register (virtual register segment) */
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| 56 | "movl %[vreg_des], %%gs\n"
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| 57 |
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| 58 | "pushl %[udata_des]\n"
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| 59 | "pushl %[stack_top]\n"
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| 60 | "pushl %[eflags]\n"
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| 61 | "pushl %[utext_des]\n"
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| 62 | "pushl %[entry]\n"
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| 63 | "movl %[uarg], %%eax\n"
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| 64 |
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| 65 | /* %edi is defined to hold pcb_ptr - set it to 0 */
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| 66 | "xorl %%edi, %%edi\n"
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| 67 |
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| 68 | "iret\n"
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| 69 | :
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| 70 | : [eflags_mask] "i" (~EFLAGS_NT),
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| 71 | [udata_des] "i" (GDT_SELECTOR(UDATA_DES) | PL_USER),
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| 72 | [stack_top] "r" ((uint8_t *) kernel_uarg->uspace_stack +
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| 73 | kernel_uarg->uspace_stack_size),
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| 74 | [eflags] "r" ((eflags & ~(EFLAGS_NT)) | EFLAGS_IF),
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| 75 | [utext_des] "i" (GDT_SELECTOR(UTEXT_DES) | PL_USER),
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| 76 | [entry] "r" (kernel_uarg->uspace_entry),
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| 77 | [uarg] "r" (kernel_uarg->uspace_uarg),
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| 78 | [vreg_des] "r" (GDT_SELECTOR(VREG_DES))
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| 79 | : "eax");
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| 80 |
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| 81 | /* Unreachable */
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| 82 | while (true)
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| 83 | ;
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| 84 | }
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| 85 |
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| 86 | /** @}
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| 87 | */
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