LowLevel/Luma3DS-3GX
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Move the code that sets up the exception handlers

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This commit is contained in:
TuxSH 2016-05-28 22:05:07 +02:00
parent 2424865fa1
commit 99d28c4f79
5 changed files with 46 additions and 38 deletions
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1
exceptions/arm9/source/handlers.h
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@ -7,7 +7,6 @@
#pragma once
void setupStack(u32 mode, void *stack);
void FIQHandler(void);
void undefinedInstructionHandler(void);
void dataAbortHandler(void);

13
exceptions/arm9/source/handlers.s
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@ -45,16 +45,3 @@ GEN_HANDLER FIQHandler
GEN_HANDLER undefinedInstructionHandler
GEN_HANDLER prefetchAbortHandler
GEN_HANDLER dataAbortHandler
.global setupStack
.type setupStack, %function
setupStack:
cmp r0, #0
moveq r0, #0xf @ usr => sys
mrs r2, cpsr
bic r3, r2, #0xf
orr r3, r0 @ processor mode
msr cpsr_c, r3 @ change processor mode
mov sp, r1
msr cpsr_c, r2 @ restore processor mode
bx lr

22
exceptions/arm9/source/main.c → exceptions/arm9/source/mainHandler.c
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@ -1,5 +1,5 @@
/*
* main.c
* mainHandler.c
* by TuxSH
*
* This is part of Luma3DS, see LICENSE.txt for details
@ -10,8 +10,6 @@
#include "handlers.h"
#define FINAL_BUFFER 0x25000000
#define SP ((void *)0x02000000) //We make the (full descending) stack point to the end of ITCM for our exception handlers.
//It doesn't matter if we're overwriting stuff, since we're going to reboot.
#define REG_DUMP_SIZE (4*17)
#define CODE_DUMP_SIZE 48
@ -71,21 +69,3 @@ void __attribute__((noreturn)) mainHandler(u32 regs[17], u32 type)
i2cWriteRegister(I2C_DEV_MCU, 0x20, 1 << 2); //Reboot
while(1);
}
void main(void)
{
setupStack(1, SP); //FIQ
setupStack(7, SP); //Abort
setupStack(11, SP); //Undefined
//IRQHandler is at 0x08000000, but we won't handle it for obvious reasons
*(vu32 *)0x08000008 = 0xE51FF004;
*(vu32 *)0x0800000C = (u32)FIQHandler;
//svcHandler is at 0x08000010, but we won't handle svc either
*(vu32 *)0x08000018 = 0xE51FF004;
*(vu32 *)0x0800001C = (u32)undefinedInstructionHandler;
*(vu32 *)0x08000020 = 0xE51FF004;
*(vu32 *)0x08000024 = (u32)prefetchAbortHandler;
*(vu32 *)0x08000028 = 0xE51FF004;
*(vu32 *)0x0800002C = (u32)dataAbortHandler;
}

9
exceptions/arm9/source/start.s
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@ -2,4 +2,11 @@
.align 4
.global _start
_start:
b main
add pc, r0, #(handlers - .) @ Dummy instruction to prevent compiler optimizations
handlers:
.word FIQHandler
.word undefinedInstructionHandler
.word prefetchAbortHandler
.word dataAbortHandler

37
source/exceptions.c
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@ -12,12 +12,47 @@
#include "utils.h"
#include "../build/arm9_exceptions.h"
#define _U __attribute__((unused)) //Silence "unused parameter" warnings
static void __attribute__((naked)) setupStack(_U u32 mode, _U void* SP)
{
__asm__ volatile(
"cmp r0, #0 \n"
"moveq r0, #0xf @ usr => sys \n"
"mrs r2, cpsr \n"
"bic r3, r2, #0xf \n"
"orr r3, r0 @ processor mode \n"
"msr cpsr_c, r3 @ change processor mode \n"
"mov sp, r1 \n"
"msr cpsr_c, r2 @ restore processor mode \n"
"bx lr \n"
);
}
#undef _U
void installArm9Handlers(void)
{
void *payloadAddress = (void *)0x01FF8000;
u32 *handlers = (u32 *)payloadAddress + 1;
void* SP = (void *)0x02000000; //We make the (full descending) stack point to the end of ITCM for our exception handlers.
//It doesn't matter if we're overwriting stuff, since we're going to reboot.
memcpy(payloadAddress, arm9_exceptions, arm9_exceptions_size);
((void (*)())payloadAddress)();
setupStack(1, SP); //FIQ
setupStack(7, SP); //Abort
setupStack(11, SP); //Undefined
const u32 offsets[] = {0x08, 0x18, 0x20, 0x28};
//IRQHandler is at 0x08000000, but we won't handle it for some reasons
//svcHandler is at 0x08000010, but we won't handle svc either
for(u32 i = 0; i < 4; i++)
{
*(vu32 *)(0x08000000 + offsets[i]) = 0xE51FF004;
*(vu32 *)(0x08000000 + offsets[i] + 4) = handlers[i];
}
}
static void hexItoa(u32 n, char *out)