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1d5d0ae9 | 1 | //\r |
2 | // Copyright (c) 2011, ARM Limited. All rights reserved.\r | |
3 | // \r | |
4 | // This program and the accompanying materials \r | |
5 | // are licensed and made available under the terms and conditions of the BSD License \r | |
6 | // which accompanies this distribution. The full text of the license may be found at \r | |
7 | // http://opensource.org/licenses/bsd-license.php \r | |
8 | //\r | |
9 | // THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, \r | |
10 | // WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED. \r | |
11 | //\r | |
12 | //\r | |
13 | \r | |
14 | EXPORT monitor_vector_table\r | |
15 | EXPORT return_from_exception\r | |
16 | EXPORT enter_monitor_mode\r | |
17 | EXPORT copy_cpsr_into_spsr\r | |
18 | \r | |
19 | AREA Helper, CODE, READONLY\r | |
20 | \r | |
21 | ALIGN 32\r | |
22 | monitor_vector_table\r | |
23 | ldr pc, dead\r | |
24 | ldr pc, dead\r | |
25 | ldr pc, dead\r | |
26 | ldr pc, dead\r | |
27 | ldr pc, dead\r | |
28 | ldr pc, dead\r | |
29 | ldr pc, dead\r | |
30 | ldr pc, dead\r | |
31 | \r | |
32 | // arg0: Secure Monitor mode stack\r | |
33 | enter_monitor_mode\r | |
34 | mov r2, lr // Save current lr\r | |
35 | \r | |
36 | mrs r1, cpsr // Save current mode (SVC) in r1\r | |
37 | bic r3, r1, #0x1f // Clear all mode bits\r | |
38 | orr r3, r3, #0x16 // Set bits for Monitor mode\r | |
39 | msr cpsr_cxsf, r3 // We are now in Monitor Mode\r | |
40 | \r | |
41 | mov sp, r0 // Use the passed sp\r | |
42 | mov lr, r2 // Use the same lr as before\r | |
43 | \r | |
44 | msr spsr_cxsf, r1 // Use saved mode for the MOVS jump to the kernel\r | |
45 | bx lr\r | |
46 | \r | |
47 | // We cannot use the instruction 'movs pc, lr' because the caller can be written either in ARM or Thumb2 assembler.\r | |
48 | // When we will jump into this function, we will set the CPSR flag to ARM assembler. By copying directly 'lr' into\r | |
49 | // 'pc'; we will not change the CPSR flag and it will crash.\r | |
50 | // The way to fix this limitation is to do the movs into the ARM assmbler code and then do a 'bx'.\r | |
51 | return_from_exception\r | |
52 | adr lr, returned_exception\r | |
53 | movs pc, lr\r | |
54 | returned_exception // We are now in non-secure state\r | |
55 | bx r0\r | |
56 | \r | |
57 | // Save the current Program Status Register (PSR) into the Saved PSR\r | |
58 | copy_cpsr_into_spsr\r | |
59 | mrs r0, cpsr\r | |
60 | msr spsr_cxsf, r0\r | |
61 | bx lr\r | |
62 | \r | |
63 | dead\r | |
64 | B dead\r | |
65 | \r | |
66 | END\r |