1/* 2 * linux/arch/arm/kernel/entry-v7m.S 3 * 4 * Copyright (C) 2008 ARM Ltd. 5 * 6 * This program is free software; you can redistribute it and/or modify 7 * it under the terms of the GNU General Public License version 2 as 8 * published by the Free Software Foundation. 9 * 10 * Low-level vector interface routines for the ARMv7-M architecture 11 */ 12#include <asm/memory.h> 13#include <asm/glue.h> 14#include <asm/thread_notify.h> 15#include <asm/v7m.h> 16 17#include "entry-header.S" 18 19#ifdef CONFIG_TRACE_IRQFLAGS 20#error "CONFIG_TRACE_IRQFLAGS not supported on the current ARMv7M implementation" 21#endif 22 23__invalid_entry: 24 v7m_exception_entry 25#ifdef CONFIG_PRINTK 26 adr r0, strerr 27 mrs r1, ipsr 28 mov r2, lr 29 bl printk 30#endif 31 mov r0, sp 32 bl show_regs 331: b 1b 34ENDPROC(__invalid_entry) 35 36strerr: .asciz "\nUnhandled exception: IPSR = %08lx LR = %08lx\n" 37 38 .align 2 39__irq_entry: 40 v7m_exception_entry 41 42 @ 43 @ Invoke the IRQ handler 44 @ 45 mrs r0, ipsr 46 ldr r1, =V7M_xPSR_EXCEPTIONNO 47 and r0, r1 48 sub r0, #16 49 mov r1, sp 50 stmdb sp!, {lr} 51 @ routine called with r0 = irq number, r1 = struct pt_regs * 52 bl nvic_handle_irq 53 54 pop {lr} 55 @ 56 @ Check for any pending work if returning to user 57 @ 58 ldr r1, =BASEADDR_V7M_SCB 59 ldr r0, [r1, V7M_SCB_ICSR] 60 tst r0, V7M_SCB_ICSR_RETTOBASE 61 beq 2f 62 63 get_thread_info tsk 64 ldr r2, [tsk, #TI_FLAGS] 65 tst r2, #_TIF_WORK_MASK 66 beq 2f @ no work pending 67 mov r0, #V7M_SCB_ICSR_PENDSVSET 68 str r0, [r1, V7M_SCB_ICSR] @ raise PendSV 69 702: 71 @ registers r0-r3 and r12 are automatically restored on exception 72 @ return. r4-r7 were not clobbered in v7m_exception_entry so for 73 @ correctness they don't need to be restored. So only r8-r11 must be 74 @ restored here. The easiest way to do so is to restore r0-r7, too. 75 ldmia sp!, {r0-r11} 76 add sp, #PT_REGS_SIZE-S_IP 77 cpsie i 78 bx lr 79ENDPROC(__irq_entry) 80 81__pendsv_entry: 82 v7m_exception_entry 83 84 ldr r1, =BASEADDR_V7M_SCB 85 mov r0, #V7M_SCB_ICSR_PENDSVCLR 86 str r0, [r1, V7M_SCB_ICSR] @ clear PendSV 87 88 @ execute the pending work, including reschedule 89 get_thread_info tsk 90 mov why, #0 91 b ret_to_user_from_irq 92ENDPROC(__pendsv_entry) 93 94/* 95 * Register switch for ARMv7-M processors. 96 * r0 = previous task_struct, r1 = previous thread_info, r2 = next thread_info 97 * previous and next are guaranteed not to be the same. 98 */ 99ENTRY(__switch_to) 100 .fnstart 101 .cantunwind 102 add ip, r1, #TI_CPU_SAVE 103 stmia ip!, {r4 - r11} @ Store most regs on stack 104 str sp, [ip], #4 105 str lr, [ip], #4 106 mov r5, r0 107 add r4, r2, #TI_CPU_SAVE 108 ldr r0, =thread_notify_head 109 mov r1, #THREAD_NOTIFY_SWITCH 110 bl atomic_notifier_call_chain 111 mov ip, r4 112 mov r0, r5 113 ldmia ip!, {r4 - r11} @ Load all regs saved previously 114 ldr sp, [ip] 115 ldr pc, [ip, #4]! 116 .fnend 117ENDPROC(__switch_to) 118 119 .data 120#if CONFIG_CPU_V7M_NUM_IRQ <= 112 121 .align 9 122#else 123 .align 10 124#endif 125 126/* 127 * Vector table (Natural alignment need to be ensured) 128 */ 129ENTRY(vector_table) 130 .long 0 @ 0 - Reset stack pointer 131 .long __invalid_entry @ 1 - Reset 132 .long __invalid_entry @ 2 - NMI 133 .long __invalid_entry @ 3 - HardFault 134 .long __invalid_entry @ 4 - MemManage 135 .long __invalid_entry @ 5 - BusFault 136 .long __invalid_entry @ 6 - UsageFault 137 .long __invalid_entry @ 7 - Reserved 138 .long __invalid_entry @ 8 - Reserved 139 .long __invalid_entry @ 9 - Reserved 140 .long __invalid_entry @ 10 - Reserved 141 .long vector_swi @ 11 - SVCall 142 .long __invalid_entry @ 12 - Debug Monitor 143 .long __invalid_entry @ 13 - Reserved 144 .long __pendsv_entry @ 14 - PendSV 145 .long __invalid_entry @ 15 - SysTick 146 .rept CONFIG_CPU_V7M_NUM_IRQ 147 .long __irq_entry @ External Interrupts 148 .endr 149 .align 2 150 .globl exc_ret 151exc_ret: 152 .space 4 153