/* * Copyright (c) 2006-2018, RT-Thread Development Team * * SPDX-License-Identifier: Apache-2.0 * * Change Logs: * Date Author Notes * 2013-07-05 Bernard the first version * 2018-11-22 Jesven in the interrupt context, use rt_scheduler_do_irq_switch checks * and switches to a new thread */ #include "rtconfig.h" .equ Mode_USR, 0x10 .equ Mode_FIQ, 0x11 .equ Mode_IRQ, 0x12 .equ Mode_SVC, 0x13 .equ Mode_ABT, 0x17 .equ Mode_UND, 0x1B .equ Mode_SYS, 0x1F .equ I_Bit, 0x80 @ when I bit is set, IRQ is disabled .equ F_Bit, 0x40 @ when F bit is set, FIQ is disabled #ifdef RT_USING_FPU .equ UND_Stack_Size, 0x00000400 #else .equ UND_Stack_Size, 0x00000000 #endif .equ SVC_Stack_Size, 0x00000400 .equ ABT_Stack_Size, 0x00000000 .equ RT_FIQ_STACK_PGSZ, 0x00000000 .equ RT_IRQ_STACK_PGSZ, 0x00000800 .equ USR_Stack_Size, 0x00000400 #define ISR_Stack_Size (UND_Stack_Size + SVC_Stack_Size + ABT_Stack_Size + \ RT_FIQ_STACK_PGSZ + RT_IRQ_STACK_PGSZ) .section .data.share.isr /* stack */ .globl stack_start .globl stack_top .align 3 stack_start: .rept ISR_Stack_Size .byte 0 .endr stack_top: .text /* reset entry */ .globl _reset _reset: /* set the cpu to SVC32 mode and disable interrupt */ cps #Mode_SVC #ifdef RT_USING_FPU mov r4, #0xfffffff mcr p15, 0, r4, c1, c0, 2 #endif /* disable the data alignment check */ mrc p15, 0, r1, c1, c0, 0 bic r1, #(1<<1) mcr p15, 0, r1, c1, c0, 0 /* setup stack */ bl stack_setup /* clear .bss */ mov r0,#0 /* get a zero */ ldr r1,=__bss_start /* bss start */ ldr r2,=__bss_end /* bss end */ bss_loop: cmp r1,r2 /* check if data to clear */ strlo r0,[r1],#4 /* clear 4 bytes */ blo bss_loop /* loop until done */ #ifdef RT_USING_SMP mrc p15, 0, r1, c1, c0, 1 mov r0, #(1<<6) orr r1, r0 mcr p15, 0, r1, c1, c0, 1 //enable smp #endif /* initialize the mmu table and enable mmu */ ldr r0, =platform_mem_desc ldr r1, =platform_mem_desc_size ldr r1, [r1] bl rt_hw_init_mmu_table bl rt_hw_mmu_init /* call C++ constructors of global objects */ ldr r0, =__ctors_start__ ldr r1, =__ctors_end__ ctor_loop: cmp r0, r1 beq ctor_end ldr r2, [r0], #4 stmfd sp!, {r0-r1} mov lr, pc bx r2 ldmfd sp!, {r0-r1} b ctor_loop ctor_end: /* start RT-Thread Kernel */ ldr pc, _rtthread_startup _rtthread_startup: .word rtthread_startup stack_setup: ldr r0, =stack_top @ Set the startup stack for svc mov sp, r0 @ Enter Undefined Instruction Mode and set its Stack Pointer msr cpsr_c, #Mode_UND|I_Bit|F_Bit mov sp, r0 sub r0, r0, #UND_Stack_Size @ Enter Abort Mode and set its Stack Pointer msr cpsr_c, #Mode_ABT|I_Bit|F_Bit mov sp, r0 sub r0, r0, #ABT_Stack_Size @ Enter FIQ Mode and set its Stack Pointer msr cpsr_c, #Mode_FIQ|I_Bit|F_Bit mov sp, r0 sub r0, r0, #RT_FIQ_STACK_PGSZ @ Enter IRQ Mode and set its Stack Pointer msr cpsr_c, #Mode_IRQ|I_Bit|F_Bit mov sp, r0 sub r0, r0, #RT_IRQ_STACK_PGSZ /* come back to SVC mode */ msr cpsr_c, #Mode_SVC|I_Bit|F_Bit bx lr /* exception handlers: undef, swi, padt, dabt, resv, irq, fiq */ .section .text.isr, "ax" .align 5 .globl vector_fiq vector_fiq: stmfd sp!,{r0-r7,lr} bl rt_hw_trap_fiq ldmfd sp!,{r0-r7,lr} subs pc, lr, #4 .globl rt_interrupt_enter .globl rt_interrupt_leave .globl rt_thread_switch_interrupt_flag .globl rt_interrupt_from_thread .globl rt_interrupt_to_thread .globl rt_current_thread .globl vmm_thread .globl vmm_virq_check .align 5 .globl vector_irq vector_irq: #ifdef RT_USING_SMP clrex stmfd sp!, {r0, r1} cps #Mode_SVC mov r0, sp /* svc_sp */ mov r1, lr /* svc_lr */ cps #Mode_IRQ sub lr, #4 stmfd r0!, {r1, lr} /* svc_lr, svc_pc */ stmfd r0!, {r2 - r12} ldmfd sp!, {r1, r2} /* original r0, r1 */ stmfd r0!, {r1 - r2} mrs r1, spsr /* original mode */ stmfd r0!, {r1} #ifdef RT_USING_LWP stmfd r0, {r13, r14}^ /* usr_sp, usr_lr */ sub r0, #8 #endif #ifdef RT_USING_FPU /* fpu context */ vmrs r6, fpexc tst r6, #(1<<30) beq 1f vstmdb r0!, {d0-d15} vstmdb r0!, {d16-d31} vmrs r5, fpscr stmfd r0!, {r5} 1: stmfd r0!, {r6} #endif /* now irq stack is clean */ /* r0 is task svc_sp */ /* backup r0 -> r8 */ mov r8, r0 bl rt_interrupt_enter bl rt_hw_trap_irq bl rt_interrupt_leave cps #Mode_SVC mov sp, r8 mov r0, r8 bl rt_scheduler_do_irq_switch b rt_hw_context_switch_exit #else stmfd sp!, {r0-r12,lr} bl rt_interrupt_enter bl rt_hw_trap_irq bl rt_interrupt_leave @ if rt_thread_switch_interrupt_flag set, jump to @ rt_hw_context_switch_interrupt_do and don't return ldr r0, =rt_thread_switch_interrupt_flag ldr r1, [r0] cmp r1, #1 beq rt_hw_context_switch_interrupt_do ldmfd sp!, {r0-r12,lr} subs pc, lr, #4 rt_hw_context_switch_interrupt_do: mov r1, #0 @ clear flag str r1, [r0] mov r1, sp @ r1 point to {r0-r3} in stack add sp, sp, #4*4 ldmfd sp!, {r4-r12,lr}@ reload saved registers mrs r0, spsr @ get cpsr of interrupt thread sub r2, lr, #4 @ save old task's pc to r2 @ Switch to SVC mode with no interrupt. If the usr mode guest is @ interrupted, this will just switch to the stack of kernel space. @ save the registers in kernel space won't trigger data abort. msr cpsr_c, #I_Bit|F_Bit|Mode_SVC stmfd sp!, {r2} @ push old task's pc stmfd sp!, {r4-r12,lr}@ push old task's lr,r12-r4 ldmfd r1, {r1-r4} @ restore r0-r3 of the interrupt thread stmfd sp!, {r1-r4} @ push old task's r0-r3 stmfd sp!, {r0} @ push old task's cpsr #ifdef RT_USING_LWP stmfd sp, {r13, r14}^ @push usr_sp, usr_lr sub sp, #8 #endif #ifdef RT_USING_FPU /* fpu context */ vmrs r6, fpexc tst r6, #(1<<30) beq 1f vstmdb sp!, {d0-d15} vstmdb sp!, {d16-d31} vmrs r5, fpscr stmfd sp!, {r5} 1: stmfd sp!, {r6} #endif ldr r4, =rt_interrupt_from_thread ldr r5, [r4] str sp, [r5] @ store sp in preempted tasks's TCB ldr r6, =rt_interrupt_to_thread ldr r6, [r6] ldr sp, [r6] @ get new task's stack pointer #ifdef RT_USING_FPU /* fpu context */ ldmfd sp!, {r6} vmsr fpexc, r6 tst r6, #(1<<30) beq 1f ldmfd sp!, {r5} vmsr fpscr, r5 vldmia sp!, {d16-d31} vldmia sp!, {d0-d15} 1: #endif #ifdef RT_USING_LWP ldmfd sp, {r13, r14}^ @pop usr_sp, usr_lr add sp, #8 #endif ldmfd sp!, {r4} @ pop new task's cpsr to spsr msr spsr_cxsf, r4 ldmfd sp!, {r0-r12,lr,pc}^ @ pop new task's r0-r12,lr & pc, copy spsr to cpsr #endif .macro push_svc_reg sub sp, sp, #17 * 4 @/* Sizeof(struct rt_hw_exp_stack) */ stmia sp, {r0 - r12} @/* Calling r0-r12 */ mov r0, sp mrs r6, spsr @/* Save CPSR */ str lr, [r0, #15*4] @/* Push PC */ str r6, [r0, #16*4] @/* Push CPSR */ cps #Mode_SVC str sp, [r0, #13*4] @/* Save calling SP */ str lr, [r0, #14*4] @/* Save calling PC */ .endm .align 5 .weak vector_swi vector_swi: push_svc_reg bl rt_hw_trap_swi b . .align 5 .globl vector_undef vector_undef: push_svc_reg cps #Mode_UND bl rt_hw_trap_undef #ifdef RT_USING_FPU ldr lr, [sp, #15*4] ldmia sp, {r0 - r12} add sp, sp, #17 * 4 movs pc, lr #endif b . .align 5 .globl vector_pabt vector_pabt: push_svc_reg bl rt_hw_trap_pabt b . .align 5 .globl vector_dabt vector_dabt: push_svc_reg bl rt_hw_trap_dabt b . .align 5 .globl vector_resv vector_resv: push_svc_reg bl rt_hw_trap_resv b . #ifdef RT_USING_SMP .global set_secondary_cpu_boot_address set_secondary_cpu_boot_address: ldr r0, =secondary_cpu_start mvn r1, #0 //0xffffffff ldr r2, =0x10000034 str r1, [r2] str r0, [r2, #-4] mov pc, lr .global secondary_cpu_start secondary_cpu_start: #ifdef RT_USING_FPU mov r4, #0xfffffff mcr p15, 0, r4, c1, c0, 2 #endif mrc p15, 0, r1, c1, c0, 1 mov r0, #(1<<6) orr r1, r0 mcr p15, 0, r1, c1, c0, 1 //enable smp mrc p15, 0, r0, c1, c0, 0 bic r0, #(1<<13) mcr p15, 0, r0, c1, c0, 0 #ifdef RT_USING_FPU cps #Mode_UND ldr sp, =und_stack_2_limit #endif cps #Mode_IRQ ldr sp, =irq_stack_2_limit cps #Mode_FIQ ldr sp, =irq_stack_2_limit cps #Mode_SVC ldr sp, =svc_stack_2_limit /* initialize the mmu table and enable mmu */ bl rt_hw_mmu_init b secondary_cpu_c_start #endif .bss .align 2 //align to 2~2=4 svc_stack_2: .space (1 << 10) svc_stack_2_limit: irq_stack_2: .space (1 << 10) irq_stack_2_limit: #ifdef RT_USING_FPU und_stack_2: .space (1 << 10) und_stack_2_limit: #endif