173 lines
5.0 KiB
ArmAsm
173 lines
5.0 KiB
ArmAsm
/*
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* File : context.S
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* This file is part of RT-Thread RTOS
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* COPYRIGHT (C) 2013, RT-Thread Development Team
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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 as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Change Logs:
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* Date Author Notes
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* 2013-07-05 Bernard the first version
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*/
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#include <rtconfig.h>
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#ifdef RT_USING_VMM
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#include <vmm.h>
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#endif
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.section .text, "ax"
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/*
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* rt_base_t rt_hw_interrupt_disable();
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*/
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.globl rt_hw_interrupt_disable
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rt_hw_interrupt_disable:
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mrs r0, cpsr
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cpsid i
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bx lr
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/*
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* void rt_hw_interrupt_enable(rt_base_t level);
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*/
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.globl rt_hw_interrupt_enable
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rt_hw_interrupt_enable:
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msr cpsr, r0
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bx lr
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/*
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* void rt_hw_context_switch_to(rt_uint32 to);
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* r0 --> to
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*/
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.globl rt_hw_context_switch_to
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rt_hw_context_switch_to:
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ldr sp, [r0] @ get new task stack pointer
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ldmfd sp!, {r4} @ pop new task spsr
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msr spsr_cxsf, r4
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ldmfd sp!, {r0-r12, lr, pc}^ @ pop new task r0-r12, lr & pc
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.section .bss.share.isr
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_guest_switch_lvl:
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.word 0
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.globl vmm_virq_update
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.section .text.isr, "ax"
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/*
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* void rt_hw_context_switch(rt_uint32 from, rt_uint32 to);
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* r0 --> from
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* r1 --> to
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*/
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.globl rt_hw_context_switch
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rt_hw_context_switch:
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stmfd sp!, {lr} @ push pc (lr should be pushed in place of PC)
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stmfd sp!, {r0-r12, lr} @ push lr & register file
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mrs r4, cpsr
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tst lr, #0x01
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orrne r4, r4, #0x20 @ it's thumb code
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stmfd sp!, {r4} @ push cpsr
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str sp, [r0] @ store sp in preempted tasks TCB
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ldr sp, [r1] @ get new task stack pointer
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#ifdef RT_USING_VMM
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#ifdef RT_VMM_USING_DOMAIN
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@ need to make sure we are in vmm domain as we would use rt_current_thread
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ldr r2, =vmm_domain_val
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ldr r7, [r2]
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mcr p15, 0, r7, c3, c0
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#endif
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/* check whether vmm thread, otherwise, update vIRQ */
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ldr r3, =rt_current_thread
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ldr r4, [r3]
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ldr r5, =vmm_thread
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cmp r4, r5
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beq switch_to_guest
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@ not falling into guest. Simple task ;-)
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ldmfd sp!, {r6} @ pop new task cpsr to spsr
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msr spsr_cxsf, r6
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ldmfd sp!, {r0-r12, lr, pc}^
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switch_to_guest:
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#ifdef RT_VMM_USING_DOMAIN
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@ the stack is saved in the guest domain so we need to
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@ come back to the guest domain to get the registers.
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ldr r1, =super_domain_val
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ldr r0, [r1]
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mcr p15, 0, r0, c3, c0
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#endif
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/* The user can do nearly anything in rt_thread_idle_excute because it will
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call the thread->cleanup. One common thing is sending events and wake up
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threads. So the guest thread will be preempted. This is the only point that
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the guest thread would call rt_hw_context_switch and "yield".
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More over, rt_schedule will call this function and this function *will*
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reentrant. If that happens, we need to make sure that call the
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rt_thread_idle_excute and vmm_virq_update again and we are in super domain.
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I use a "reference count" to achieve such behaviour. If you have better
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idea, tell me. */
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ldr r4, =_guest_switch_lvl
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ldr r5, [r4]
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add r5, r5, #1
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str r5, [r4]
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cmp r5, #1
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bne _switch_through
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bl rt_thread_idle_excute
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bl vmm_virq_update
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/* we need _guest_switch_lvl to protect until _switch_through, but it's OK
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* to cleanup the reference count here because the code below will not be
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* reentrant. */
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sub r5, r5, #1
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str r5, [r4]
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#ifdef RT_VMM_USING_DOMAIN
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ldr r1, =guest_domain_val
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ldr r0, [r1]
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mcr p15, 0, r0, c3, c0
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#endif
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_switch_through:
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#endif /* RT_USING_VMM */
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ldmfd sp!, {r4} @ pop new task cpsr to spsr
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msr spsr_cxsf, r4
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ldmfd sp!, {r0-r12, lr, pc}^ @ pop new task r0-r12, lr & pc, copy spsr to cpsr
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/*
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* void rt_hw_context_switch_interrupt(rt_uint32 from, rt_uint32 to);
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*/
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.globl rt_thread_switch_interrupt_flag
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.globl rt_interrupt_from_thread
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.globl rt_interrupt_to_thread
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.globl rt_hw_context_switch_interrupt
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rt_hw_context_switch_interrupt:
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ldr r2, =rt_thread_switch_interrupt_flag
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ldr r3, [r2]
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cmp r3, #1
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beq _reswitch
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ldr ip, =rt_interrupt_from_thread @ set rt_interrupt_from_thread
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mov r3, #1 @ set rt_thread_switch_interrupt_flag to 1
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str r0, [ip]
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str r3, [r2]
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_reswitch:
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ldr r2, =rt_interrupt_to_thread @ set rt_interrupt_to_thread
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str r1, [r2]
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bx lr
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