diff options
Diffstat (limited to 'arch/arm/kernel/entry-v7m.S')
| -rw-r--r-- | arch/arm/kernel/entry-v7m.S | 160 |
1 files changed, 160 insertions, 0 deletions
diff --git a/arch/arm/kernel/entry-v7m.S b/arch/arm/kernel/entry-v7m.S new file mode 100644 index 0000000000..52bacf07ba --- /dev/null +++ b/arch/arm/kernel/entry-v7m.S @@ -0,0 +1,160 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * linux/arch/arm/kernel/entry-v7m.S + * + * Copyright (C) 2008 ARM Ltd. + * + * Low-level vector interface routines for the ARMv7-M architecture + */ +#include <asm/page.h> +#include <asm/glue.h> +#include <asm/thread_notify.h> +#include <asm/v7m.h> + +#include "entry-header.S" + +#ifdef CONFIG_TRACE_IRQFLAGS +#error "CONFIG_TRACE_IRQFLAGS not supported on the current ARMv7M implementation" +#endif + +__invalid_entry: + v7m_exception_entry +#ifdef CONFIG_PRINTK + adr r0, strerr + mrs r1, ipsr + mov r2, lr + bl _printk +#endif + mov r0, sp + bl show_regs +1: b 1b +ENDPROC(__invalid_entry) + +strerr: .asciz "\nUnhandled exception: IPSR = %08lx LR = %08lx\n" + + .align 2 +__irq_entry: + v7m_exception_entry + + @ + @ Invoke the IRQ handler + @ + mov r0, sp + ldr_this_cpu sp, irq_stack_ptr, r1, r2 + + @ + @ If we took the interrupt while running in the kernel, we may already + @ be using the IRQ stack, so revert to the original value in that case. + @ + subs r2, sp, r0 @ SP above bottom of IRQ stack? + rsbscs r2, r2, #THREAD_SIZE @ ... and below the top? + movcs sp, r0 + + push {r0, lr} @ preserve LR and original SP + + @ routine called with r0 = struct pt_regs * + bl generic_handle_arch_irq + + pop {r0, lr} + mov sp, r0 + + @ + @ Check for any pending work if returning to user + @ + ldr r1, =BASEADDR_V7M_SCB + ldr r0, [r1, V7M_SCB_ICSR] + tst r0, V7M_SCB_ICSR_RETTOBASE + beq 2f + + get_thread_info tsk + ldr r2, [tsk, #TI_FLAGS] + movs r2, r2, lsl #16 + beq 2f @ no work pending + mov r0, #V7M_SCB_ICSR_PENDSVSET + str r0, [r1, V7M_SCB_ICSR] @ raise PendSV + +2: + @ registers r0-r3 and r12 are automatically restored on exception + @ return. r4-r7 were not clobbered in v7m_exception_entry so for + @ correctness they don't need to be restored. So only r8-r11 must be + @ restored here. The easiest way to do so is to restore r0-r7, too. + ldmia sp!, {r0-r11} + add sp, #PT_REGS_SIZE-S_IP + cpsie i + bx lr +ENDPROC(__irq_entry) + +__pendsv_entry: + v7m_exception_entry + + ldr r1, =BASEADDR_V7M_SCB + mov r0, #V7M_SCB_ICSR_PENDSVCLR + str r0, [r1, V7M_SCB_ICSR] @ clear PendSV + + @ execute the pending work, including reschedule + get_thread_info tsk + mov why, #0 + b ret_to_user_from_irq +ENDPROC(__pendsv_entry) + +/* + * Register switch for ARMv7-M processors. + * r0 = previous task_struct, r1 = previous thread_info, r2 = next thread_info + * previous and next are guaranteed not to be the same. + */ +ENTRY(__switch_to) + .fnstart + .cantunwind + add ip, r1, #TI_CPU_SAVE + stmia ip!, {r4 - r11} @ Store most regs on stack + str sp, [ip], #4 + str lr, [ip], #4 + mov r5, r0 + mov r6, r2 @ Preserve 'next' + add r4, r2, #TI_CPU_SAVE + ldr r0, =thread_notify_head + mov r1, #THREAD_NOTIFY_SWITCH + bl atomic_notifier_call_chain + mov r0, r5 + mov r1, r6 + ldmia r4, {r4 - r12, lr} @ Load all regs saved previously + set_current r1, r2 + mov sp, ip + bx lr + .fnend +ENDPROC(__switch_to) + + .data +#if CONFIG_CPU_V7M_NUM_IRQ <= 112 + .align 9 +#else + .align 10 +#endif + +/* + * Vector table (Natural alignment need to be ensured) + */ +ENTRY(vector_table) + .long 0 @ 0 - Reset stack pointer + .long __invalid_entry @ 1 - Reset + .long __invalid_entry @ 2 - NMI + .long __invalid_entry @ 3 - HardFault + .long __invalid_entry @ 4 - MemManage + .long __invalid_entry @ 5 - BusFault + .long __invalid_entry @ 6 - UsageFault + .long __invalid_entry @ 7 - Reserved + .long __invalid_entry @ 8 - Reserved + .long __invalid_entry @ 9 - Reserved + .long __invalid_entry @ 10 - Reserved + .long vector_swi @ 11 - SVCall + .long __invalid_entry @ 12 - Debug Monitor + .long __invalid_entry @ 13 - Reserved + .long __pendsv_entry @ 14 - PendSV + .long __invalid_entry @ 15 - SysTick + .rept CONFIG_CPU_V7M_NUM_IRQ + .long __irq_entry @ External Interrupts + .endr + .align 2 + .globl exc_ret +exc_ret: + .space 4 |