/* * Copyright (c) 2013-2018 Arm Limited. All rights reserved. * * SPDX-License-Identifier: Apache-2.0 * * Licensed under the Apache License, Version 2.0 (the License); you may * not use this file except in compliance with the License. * You may obtain a copy of the License at * * www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an AS IS BASIS, WITHOUT * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. * * ----------------------------------------------------------------------------- * * Project: CMSIS-RTOS RTX * Title: Cortex-A Exception handlers * * ----------------------------------------------------------------------------- */ .file "irq_ca.S" .syntax unified .equ MODE_FIQ, 0x11 .equ MODE_IRQ, 0x12 .equ MODE_SVC, 0x13 .equ MODE_ABT, 0x17 .equ MODE_UND, 0x1B .equ CPSR_BIT_T, 0x20 .equ K_STATE_RUNNING, 2 // osKernelState_t::osKernelRunning .equ I_K_STATE_OFS, 8 // osRtxInfo.kernel.state offset .equ I_TICK_IRQN_OFS, 16 // osRtxInfo.tick_irqn offset .equ I_T_RUN_OFS, 20 // osRtxInfo.thread.run offset .equ TCB_SP_FRAME, 34 // osRtxThread_t.stack_frame offset .equ TCB_SP_OFS, 56 // osRtxThread_t.sp offset .section ".rodata" .global irqRtxLib // Non weak library reference irqRtxLib: .byte 0 .section ".data" .global IRQ_PendSV IRQ_NestLevel: .word 0 // IRQ nesting level counter IRQ_PendSV: .byte 0 // Pending SVC flag SVC_Active: .byte 0 // SVC handler execution active flag .arm .section ".text" .align 4 .type Undef_Handler, %function .global Undef_Handler .fnstart .cantunwind Undef_Handler: SRSFD SP!, #MODE_UND PUSH {R0-R4, R12} // Save APCS corruptible registers to UND mode stack MRS R0, SPSR TST R0, #CPSR_BIT_T // Check mode MOVEQ R1, #4 // R1 = 4 ARM mode MOVNE R1, #2 // R1 = 2 Thumb mode SUB R0, LR, R1 LDREQ R0, [R0] // ARM mode - R0 points to offending instruction BEQ Undef_Cont // Thumb instruction // Determine if it is a 32-bit Thumb instruction LDRH R0, [R0] MOV R2, #0x1C CMP R2, R0, LSR #11 BHS Undef_Cont // 16-bit Thumb instruction // 32-bit Thumb instruction. Unaligned - reconstruct the offending instruction LDRH R2, [LR] ORR R0, R2, R0, LSL #16 Undef_Cont: MOV R2, LR // Set LR to third argument AND R12, SP, #4 // Ensure stack is 8-byte aligned SUB SP, SP, R12 // Adjust stack PUSH {R12, LR} // Store stack adjustment and dummy LR // R0 =Offending instruction, R1 =2(Thumb) or =4(ARM) BL CUndefHandler POP {R12, LR} // Get stack adjustment & discard dummy LR ADD SP, SP, R12 // Unadjust stack LDR LR, [SP, #24] // Restore stacked LR and possibly adjust for retry SUB LR, LR, R0 LDR R0, [SP, #28] // Restore stacked SPSR MSR SPSR_cxsf, R0 POP {R0-R4, R12} // Restore stacked APCS registers ADD SP, SP, #8 // Adjust SP for already-restored banked registers MOVS PC, LR .fnend .size Undef_Handler, .-Undef_Handler .type PAbt_Handler, %function .global PAbt_Handler .fnstart .cantunwind PAbt_Handler: SUB LR, LR, #4 // Pre-adjust LR SRSFD SP!, #MODE_ABT // Save LR and SPRS to ABT mode stack PUSH {R0-R4, R12} // Save APCS corruptible registers to ABT mode stack MRC p15, 0, R0, c5, c0, 1 // IFSR MRC p15, 0, R1, c6, c0, 2 // IFAR MOV R2, LR // Set LR to third argument AND R12, SP, #4 // Ensure stack is 8-byte aligned SUB SP, SP, R12 // Adjust stack PUSH {R12, LR} // Store stack adjustment and dummy LR BL CPAbtHandler POP {R12, LR} // Get stack adjustment & discard dummy LR ADD SP, SP, R12 // Unadjust stack POP {R0-R4, R12} // Restore stack APCS registers RFEFD SP! // Return from exception .fnend .size PAbt_Handler, .-PAbt_Handler .type DAbt_Handler, %function .global DAbt_Handler .fnstart .cantunwind DAbt_Handler: SUB LR, LR, #8 // Pre-adjust LR SRSFD SP!, #MODE_ABT // Save LR and SPRS to ABT mode stack PUSH {R0-R4, R12} // Save APCS corruptible registers to ABT mode stack CLREX // State of exclusive monitors unknown after taken data abort MRC p15, 0, R0, c5, c0, 0 // DFSR MRC p15, 0, R1, c6, c0, 0 // DFAR MOV R2, LR // Set LR to third argument AND R12, SP, #4 // Ensure stack is 8-byte aligned SUB SP, SP, R12 // Adjust stack PUSH {R12, LR} // Store stack adjustment and dummy LR BL CDAbtHandler POP {R12, LR} // Get stack adjustment & discard dummy LR ADD SP, SP, R12 // Unadjust stack POP {R0-R4, R12} // Restore stacked APCS registers RFEFD SP! // Return from exception .fnend .size DAbt_Handler, .-DAbt_Handler .type IRQ_Handler, %function .global IRQ_Handler .fnstart .cantunwind IRQ_Handler: SUB LR, LR, #4 // Pre-adjust LR SRSFD SP!, #MODE_SVC // Save LR_irq and SPRS_irq on to the SVC stack CPS #MODE_SVC // Change to SVC mode PUSH {R0-R3, R12, LR} // Save APCS corruptible registers MOV R3, SP // Move SP into R3 AND R3, R3, #4 // Get stack adjustment to ensure 8-byte alignment SUB SP, SP, R3 // Adjust stack PUSH {R3, R4} // Store stack adjustment(R3) and user data(R4) BLX IRQ_GetActiveIRQ // Retrieve interrupt ID into R0 MOV R4, R0 // Move interrupt ID to R4 LDR R1, =IRQ_NestLevel LDR R3, [R1] // Load IRQ nest level and increment it ADD R3, R3, #1 STR R3, [R1] BLX IRQ_GetHandler // Retrieve interrupt handler address for current ID CMP R0, #0 // Check if handler address is 0 BEQ IRQ_End // If 0, end interrupt and return CPSIE i // Re-enable interrupts BLX R0 // Call IRQ handler CPSID i // Disable interrupts IRQ_End: MOV R0, R4 // Move interrupt ID to R0 BLX IRQ_EndOfInterrupt // Signal end of interrupt LDR R2, =IRQ_NestLevel LDR R1, [R2] // Load IRQ nest level and SUBS R1, R1, #1 // decrement it STR R1, [R2] BNE IRQ_Exit // Not zero, exit from IRQ handler LDR R0, =SVC_Active LDRB R0, [R0] // Load SVC_Active flag CMP R0, #0 BNE IRQ_SwitchCheck // Skip post processing when SVC active // RTX IRQ post processing check PUSH {R5, R6} // Save user R5 and R6 MOV R6, #0 LDR R5, =IRQ_PendSV // Load address of IRQ_PendSV flag B IRQ_PendCheck IRQ_PendExec: STRB R6, [R5] // Clear PendSV flag CPSIE i // Re-enable interrupts BLX osRtxPendSV_Handler // Post process pending objects CPSID i // Disable interrupts IRQ_PendCheck: LDRB R0, [R5] // Load PendSV flag CMP R0, #1 // Compare PendSV value BEQ IRQ_PendExec // Branch to IRQ_PendExec if PendSV is set POP {R5, R6} // Restore user R5 and R6 IRQ_SwitchCheck: // RTX IRQ context switch check LDR R12, =osRtxInfo+I_T_RUN_OFS // Load address of osRtxInfo.run LDM R12, {R0, R1} // Load osRtxInfo.thread.run: curr & next CMP R0, R1 // Check if context switch is required BEQ IRQ_Exit POP {R3, R4} // Restore stack adjustment(R3) and user data(R4) ADD SP, SP, R3 // Unadjust stack B osRtxContextSwitch IRQ_Exit: POP {R3, R4} // Restore stack adjustment(R3) and user data(R4) ADD SP, SP, R3 // Unadjust stack POP {R0-R3, R12, LR} // Restore stacked APCS registers RFEFD SP! // Return from IRQ handler .fnend .size IRQ_Handler, .-IRQ_Handler .type SVC_Handler, %function .global SVC_Handler .fnstart .cantunwind SVC_Handler: SRSFD SP!, #MODE_SVC // Store SPSR_svc and LR_svc onto SVC stack PUSH {R12, LR} MRS R12, SPSR // Load SPSR TST R12, #CPSR_BIT_T // Thumb bit set? LDRHNE R12, [LR,#-2] // Thumb: load halfword BICNE R12, R12, #0xFF00 // extract SVC number LDREQ R12, [LR,#-4] // ARM: load word BICEQ R12, R12, #0xFF000000 // extract SVC number CMP R12, #0 // Compare SVC number BNE SVC_User // Branch if User SVC PUSH {R0-R3} LDR R3, =osRtxInfo LDR R1, [R3, #I_K_STATE_OFS] // Load RTX5 kernel state CMP R1, #K_STATE_RUNNING // Check osKernelRunning BLT SVC_FuncCall // Continue if kernel is not running LDR R0, [R3, #I_TICK_IRQN_OFS] // Load OS Tick irqn BLX IRQ_Disable // Disable OS Tick interrupt SVC_FuncCall: LDR R0, =SVC_Active MOV R1, #1 STRB R1, [R0] // Set SVC_Active flag POP {R0-R3} LDR R12, [SP] // Reload R12 from stack CPSIE i // Re-enable interrupts BLX R12 // Branch to SVC function CPSID i // Disable interrupts SUB SP, SP, #4 // Adjust SP STM SP, {SP}^ // Store SP_usr onto stack POP {R12} // Pop SP_usr into R12 SUB R12, R12, #16 // Adjust pointer to SP_usr LDMDB R12, {R2,R3} // Load return values from SVC function PUSH {R0-R3} // Push return values to stack PUSH {R4, R5} // Save R4 and R5 MOV R5, #0 LDR R4, =IRQ_PendSV // Load address of IRQ_PendSV B SVC_PendCheck SVC_PendExec: STRB R5, [R4] // Clear IRQ_PendSV flag CPSIE i // Re-enable interrupts BLX osRtxPendSV_Handler // Post process pending objects CPSID i // Disable interrupts SVC_PendCheck: LDRB R0, [R4] // Load IRQ_PendSV flag CMP R0, #1 // Compare IRQ_PendSV value BEQ SVC_PendExec // Branch to SVC_PendExec if IRQ_PendSV is set POP {R4, R5} // Restore R4 and R5 LDR R0, =SVC_Active MOV R1, #0 STRB R1, [R0] // Clear SVC_Active flag LDR R12, =osRtxInfo LDR R1, [R12, #I_K_STATE_OFS] // Load RTX5 kernel state CMP R1, #K_STATE_RUNNING // Check osKernelRunning BLT SVC_ContextCheck // Continue if kernel is not running LDR R0, [R12, #I_TICK_IRQN_OFS] // Load OS Tick irqn BLX IRQ_Enable // Enable OS Tick interrupt SVC_ContextCheck: ADD R12, R12, #I_T_RUN_OFS // Load address of osRtxInfo.thread.run LDM R12, {R0, R1} // Load osRtxInfo.thread.run: curr & next CMP R0, R1 // Check if context switch is required BEQ osRtxContextExit // Exit if curr and next are equal B osRtxContextSwitch // Continue in context switcher SVC_User: PUSH {R4, R5} LDR R5,=osRtxUserSVC // Load address of SVC table LDR R4,[R5] // Load SVC maximum number CMP R12,R4 // Check SVC number range BHI SVC_Done // Branch if out of range LDR R12,[R5,R12,LSL #2] // Load SVC Function Address BLX R12 // Call SVC Function SVC_Done: POP {R4, R5, R12, LR} RFEFD SP! // Return from exception .fnend .size SVC_Handler, .-SVC_Handler .type osRtxContextSwitch, %function .global osRtxContextSwitch .fnstart .cantunwind osRtxContextSwitch: // R0 = osRtxInfo.thread.run.curr // R1 = osRtxInfo.thread.run.next // R12 = &osRtxInfo.thread.run CMP R0, #0 // Is osRtxInfo.thread.run.curr == 0 ADDEQ SP, SP, #32 // Equal, curr deleted, adjust current SP BEQ osRtxContextRestore // Restore context, run.curr = run.next; osRtxContextSave: SUB SP, SP, #4 STM SP, {SP}^ // Save SP_usr to current stack POP {R3} // Pop SP_usr into R3 SUB R3, R3, #64 // Adjust user sp to end of basic frame (R4) STMIA R3!, {R4-R11} // Save R4-R11 to user POP {R4-R8} // Pop current R0-R12 into R4-R8 STMIA R3!, {R4-R8} // Store them to user stack STM R3, {LR}^ // Store LR_usr directly ADD R3, R3, #4 // Adjust user sp to PC POP {R4-R6} // Pop current LR, PC, CPSR STMIA R3!, {R5-R6} // Restore user PC and CPSR SUB R3, R3, #64 // Adjust user sp to R4 // Check if VFP state need to be saved MRC p15, 0, R2, c1, c0, 2 // VFP/NEON access enabled? (CPACR) AND R2, R2, #0x00F00000 CMP R2, #0x00F00000 BNE osRtxContextSave1 // Continue, no VFP VMRS R2, FPSCR STMDB R3!, {R2,R12} // Push FPSCR, maintain 8-byte alignment VSTMDB R3!, {D0-D15} // Save D0-D15 #if __ARM_NEON == 1 VSTMDB R3!, {D16-D31} // Save D16-D31 #endif LDRB R2, [R0, #TCB_SP_FRAME] #if __ARM_NEON == 1 ORR R2, R2, #4 // NEON state #else ORR R2, R2, #2 // VFP state #endif STRB R2, [R0, #TCB_SP_FRAME] // Record VFP/NEON state osRtxContextSave1: STR R3, [R0, #TCB_SP_OFS] // Store user sp to osRtxInfo.thread.run.curr osRtxContextRestore: STR R1, [R12] // Store run.next to run.curr LDR R3, [R1, #TCB_SP_OFS] // Load next osRtxThread_t.sp LDRB R2, [R1, #TCB_SP_FRAME] // Load next osRtxThread_t.stack_frame ANDS R2, R2, #0x6 // Check stack frame for VFP context MRC p15, 0, R2, c1, c0, 2 // Read CPACR ANDEQ R2, R2, #0xFF0FFFFF // Disable VFP/NEON access if incoming task does not have stacked VFP/NEON state ORRNE R2, R2, #0x00F00000 // Enable VFP/NEON access if incoming task does have stacked VFP/NEON state MCR p15, 0, R2, c1, c0, 2 // Write CPACR BEQ osRtxContextRestore1 // No VFP ISB // Only sync if we enabled VFP, otherwise we will context switch before next VFP instruction anyway #if __ARM_NEON == 1 VLDMIA R3!, {D16-D31} // Restore D16-D31 #endif VLDMIA R3!, {D0-D15} // Restore D0-D15 LDR R2, [R3] VMSR FPSCR, R2 // Restore FPSCR ADD R3, R3, #8 osRtxContextRestore1: LDMIA R3!, {R4-R11} // Restore R4-R11 MOV R12, R3 // Move sp pointer to R12 ADD R3, R3, #32 // Adjust sp PUSH {R3} // Push sp onto stack LDMIA SP, {SP}^ // Restore SP_usr ADD SP, SP, #4 // Adjust SP_svc LDMIA R12!, {R0-R3} // Restore User R0-R3 LDR LR, [R12, #12] // Load SPSR into LR MSR SPSR_cxsf, LR // Restore SPSR ADD R12, R12, #4 // Adjust pointer to LR LDM R12, {LR}^ // Restore LR_usr directly into LR LDR LR, [R12, #4] // Restore LR LDR R12, [R12, #-4] // Restore R12 MOVS PC, LR // Return from exception osRtxContextExit: POP {R0-R3, R12, LR} // Restore stacked APCS registers RFEFD SP! // Return from exception .fnend .size osRtxContextSwitch, .-osRtxContextSwitch .end