1 #======================================================================================== 2 # Copyright (c) 2011-2014, ARM Limited. All rights reserved. 3 # 4 # This program and the accompanying materials 5 # are licensed and made available under the terms and conditions of the BSD License 6 # which accompanies this distribution. The full text of the license may be found at 7 # http://opensource.org/licenses/bsd-license.php 8 # 9 # THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, 10 # WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED. 11 # 12 #======================================================================================= 13 14 #start of the code section 15 .text 16 .align 3 17 18 GCC_ASM_EXPORT(return_from_exception) 19 GCC_ASM_EXPORT(enter_monitor_mode) 20 GCC_ASM_EXPORT(copy_cpsr_into_spsr) 21 GCC_ASM_EXPORT(set_non_secure_mode) 22 23 # r0: Monitor World EntryPoint 24 # r1: MpId 25 # r2: SecBootMode 26 # r3: Secure Monitor mode stack 27 ASM_PFX(enter_monitor_mode): 28 cmp r3, #0 @ If a Secure Monitor stack base has not been defined then use the Secure stack 29 moveq r3, sp 30 31 mrs r4, cpsr @ Save current mode (SVC) in r4 32 bic r5, r4, #0x1f @ Clear all mode bits 33 orr r5, r5, #0x16 @ Set bits for Monitor mode 34 msr cpsr_cxsf, r5 @ We are now in Monitor Mode 35 36 mov sp, r3 @ Set the stack of the Monitor Mode 37 38 mov lr, r0 @ Use the pass entrypoint as lr 39 40 msr spsr_cxsf, r4 @ Use saved mode for the MOVS jump to the kernel 41 42 mov r4, r0 @ Swap EntryPoint and MpId registers 43 mov r0, r1 44 mov r1, r2 45 mov r2, r3 46 47 bx r4 48 49 # Return-from-exception is not an interworking return, so we must do it 50 # in two steps, in case r0 has the Thumb bit set. 51 ASM_PFX(return_from_exception): 52 adr lr, returned_exception 53 movs pc, lr 54 returned_exception: @ We are now in non-secure state 55 bx r0 56 57 # Save the current Program Status Register (PSR) into the Saved PSR 58 ASM_PFX(copy_cpsr_into_spsr): 59 mrs r0, cpsr 60 msr spsr_cxsf, r0 61 bx lr 62 63 # Set the Non Secure Mode 64 ASM_PFX(set_non_secure_mode): 65 push { r1 } 66 and r0, r0, #0x1f @ Keep only the mode bits 67 mrs r1, spsr @ Read the spsr 68 bic r1, r1, #0x1f @ Clear all mode bits 69 orr r1, r1, r0 70 msr spsr_cxsf, r1 @ write back spsr (may have caused a mode switch) 71 isb 72 pop { r1 } 73 bx lr @ return (hopefully thumb-safe!) 74 75 ASM_FUNCTION_REMOVE_IF_UNREFERENCED 76
