Subversion Repositories HelenOS

Rev

Rev 4018 | Details | Compare with Previous | Last modification | View Log | RSS feed

Rev Author Line No. Line
2362 jancik 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 arm32
30
 * @{
31
 */
32
/** @file
2413 kebrt 33
 *  @brief Userspace switch.
2362 jancik 34
 */
35
 
36
#include <userspace.h>
37
 
2413 kebrt 38
/** Struct for holding all general purpose registers.
39
 *  
40
 *  Used to set registers when going to userspace.
41
 */
2362 jancik 42
typedef struct {
43
	uint32_t r0;
44
	uint32_t r1;
45
	uint32_t r2;
46
	uint32_t r3;
47
	uint32_t r4;
48
	uint32_t r5;
49
	uint32_t r6;
50
	uint32_t r7;
51
	uint32_t r8;
52
	uint32_t r9;
53
	uint32_t r10;
54
	uint32_t r11;
55
	uint32_t r12;
56
	uint32_t sp;
57
	uint32_t lr;
58
	uint32_t pc;
59
} ustate_t;
60
 
2464 jermar 61
/** Changes processor mode and jumps to the address specified in the first
62
 * parameter.
2362 jancik 63
 *
64
 *  @param kernel_uarg	 Userspace settings (entry point, stack, ...).
65
 */
66
void userspace(uspace_arg_t *kernel_uarg)
67
{
68
	volatile ustate_t ustate;
69
 
2464 jermar 70
	/* set first parameter */
2362 jancik 71
	ustate.r0 = (uintptr_t) kernel_uarg->uspace_uarg;
72
 
3222 svoboda 73
	/* %r1 is defined to hold pcb_ptr - set it to 0 */
74
	ustate.r1 = 0;
75
 
2464 jermar 76
	/* clear other registers */
3222 svoboda 77
	ustate.r2 = ustate.r3  = ustate.r4  = ustate.r5 =
2464 jermar 78
	    ustate.r6  = ustate.r7  = ustate.r8  = ustate.r9 = ustate.r10 = 
79
	    ustate.r11 = ustate.r12 = ustate.lr = 0;
2362 jancik 80
 
2464 jermar 81
	/* set user stack */
2413 kebrt 82
	ustate.sp = ((uint32_t)kernel_uarg->uspace_stack) + PAGE_SIZE;
2362 jancik 83
 
2464 jermar 84
	/* set where uspace execution starts */
2362 jancik 85
	ustate.pc = (uintptr_t) kernel_uarg->uspace_entry;
86
 
2464 jermar 87
	/* status register in user mode */
88
	ipl_t user_mode = current_status_reg_read() &
89
	    (~STATUS_REG_MODE_MASK | USER_MODE);
2362 jancik 90
 
2464 jermar 91
	/* set user mode, set registers, jump */
92
	asm volatile (
4018 decky 93
		"mov sp, %[ustate]\n"
94
		"msr spsr_c, %[user_mode]\n"
95
		"ldmfd sp!, {r0-r12, sp, lr}^\n"
2477 kebrt 96
		"ldmfd sp!, {pc}^\n"
4018 decky 97
		:: [ustate] "r" (&ustate), [user_mode] "r" (user_mode)
2362 jancik 98
	);
99
 
2464 jermar 100
	/* unreachable */
101
	while(1)
102
		;
2362 jancik 103
}
104
 
105
/** @}
106
 */