ARM: ARMv7-M: Add support for exception handling
This patch implements the exception handling for the ARMv7-M architecture (pretty different from the A or R profiles). It bases on work done earlier by Catalin for 2.6.33 but was nearly completely rewritten to use a pt_regs layout compatible to the A profile. Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Reviewed-by: Jonathan Austin <jonathan.austin@arm.com> Tested-by: Jonathan Austin <jonathan.austin@arm.com> Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
This commit is contained in:
Uwe Kleine-König
143
arch/arm/kernel/entry-v7m.S
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143
arch/arm/kernel/entry-v7m.S
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/*
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* linux/arch/arm/kernel/entry-v7m.S
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*
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* Copyright (C) 2008 ARM Ltd.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* Low-level vector interface routines for the ARMv7-M architecture
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*/
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#include <asm/memory.h>
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#include <asm/glue.h>
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#include <asm/thread_notify.h>
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#include <asm/v7m.h>
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#include <mach/entry-macro.S>
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#include "entry-header.S"
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#ifdef CONFIG_TRACE_IRQFLAGS
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#error "CONFIG_TRACE_IRQFLAGS not supported on the current ARMv7M implementation"
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#endif
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__invalid_entry:
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v7m_exception_entry
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adr r0, strerr
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mrs r1, ipsr
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mov r2, lr
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bl printk
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mov r0, sp
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bl show_regs
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1: b 1b
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ENDPROC(__invalid_entry)
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strerr: .asciz "\nUnhandled exception: IPSR = %08lx LR = %08lx\n"
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.align 2
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__irq_entry:
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v7m_exception_entry
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@
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@ Invoke the IRQ handler
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@
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mrs r0, ipsr
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ldr r1, =V7M_xPSR_EXCEPTIONNO
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and r0, r1
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sub r0, #16
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mov r1, sp
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stmdb sp!, {lr}
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@ routine called with r0 = irq number, r1 = struct pt_regs *
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bl nvic_do_IRQ
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pop {lr}
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@
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@ Check for any pending work if returning to user
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@
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ldr r1, =BASEADDR_V7M_SCB
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ldr r0, [r1, V7M_SCB_ICSR]
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tst r0, V7M_SCB_ICSR_RETTOBASE
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beq 2f
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get_thread_info tsk
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ldr r2, [tsk, #TI_FLAGS]
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tst r2, #_TIF_WORK_MASK
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beq 2f @ no work pending
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mov r0, #V7M_SCB_ICSR_PENDSVSET
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str r0, [r1, V7M_SCB_ICSR] @ raise PendSV
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2:
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@ registers r0-r3 and r12 are automatically restored on exception
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@ return. r4-r7 were not clobbered in v7m_exception_entry so for
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@ correctness they don't need to be restored. So only r8-r11 must be
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@ restored here. The easiest way to do so is to restore r0-r7, too.
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ldmia sp!, {r0-r11}
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add sp, #S_FRAME_SIZE-S_IP
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cpsie i
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bx lr
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ENDPROC(__irq_entry)
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__pendsv_entry:
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v7m_exception_entry
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ldr r1, =BASEADDR_V7M_SCB
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mov r0, #V7M_SCB_ICSR_PENDSVCLR
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str r0, [r1, V7M_SCB_ICSR] @ clear PendSV
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@ execute the pending work, including reschedule
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get_thread_info tsk
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mov why, #0
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b ret_to_user
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ENDPROC(__pendsv_entry)
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/*
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* Register switch for ARMv7-M processors.
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* r0 = previous task_struct, r1 = previous thread_info, r2 = next thread_info
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* previous and next are guaranteed not to be the same.
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*/
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ENTRY(__switch_to)
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.fnstart
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.cantunwind
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add ip, r1, #TI_CPU_SAVE
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stmia ip!, {r4 - r11} @ Store most regs on stack
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str sp, [ip], #4
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str lr, [ip], #4
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mov r5, r0
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add r4, r2, #TI_CPU_SAVE
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ldr r0, =thread_notify_head
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mov r1, #THREAD_NOTIFY_SWITCH
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bl atomic_notifier_call_chain
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mov ip, r4
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mov r0, r5
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ldmia ip!, {r4 - r11} @ Load all regs saved previously
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ldr sp, [ip]
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ldr pc, [ip, #4]!
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.fnend
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ENDPROC(__switch_to)
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.data
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.align 8
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/*
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* Vector table (64 words => 256 bytes natural alignment)
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*/
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ENTRY(vector_table)
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.long 0 @ 0 - Reset stack pointer
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.long __invalid_entry @ 1 - Reset
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.long __invalid_entry @ 2 - NMI
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.long __invalid_entry @ 3 - HardFault
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.long __invalid_entry @ 4 - MemManage
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.long __invalid_entry @ 5 - BusFault
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.long __invalid_entry @ 6 - UsageFault
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.long __invalid_entry @ 7 - Reserved
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.long __invalid_entry @ 8 - Reserved
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.long __invalid_entry @ 9 - Reserved
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.long __invalid_entry @ 10 - Reserved
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.long vector_swi @ 11 - SVCall
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.long __invalid_entry @ 12 - Debug Monitor
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.long __invalid_entry @ 13 - Reserved
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.long __pendsv_entry @ 14 - PendSV
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.long __invalid_entry @ 15 - SysTick
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.rept 64 - 16
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.long __irq_entry @ 16..64 - External Interrupts
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.endr
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