LowLevel/Luma3DS-3GX
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Prevent double faults when either PC or SP is invalid

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TuxSH
2016-07-14 20:08:31 +02:00
parent d5190cd788
commit 004f0652c9
9 changed files with 80 additions and 8 deletions
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1
exceptions/arm11/source/handlers.h
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@@ -26,6 +26,7 @@
void __attribute__((noreturn)) mcuReboot(void);
void cleanInvalidateDCacheAndDMB(void);
bool cannotAccessVA(const void *address);
void FIQHandler(void);
void undefinedInstructionHandler(void);

11
exceptions/arm11/source/handlers.s
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@@ -116,3 +116,14 @@ cleanInvalidateDCacheAndDMB:
mcr p15,0,r0,c7,c14,0 @ Clean and Invalidate Entire Data Cache
mcr p15,0,r0,c7,c10,4 @ Drain Memory Barrier
bx lr
.global cannotAccessVA
.type cannotAccessVA, %function
cannotAccessVA:
@ Thanks yellows8 for the hint
lsr r0, #12
lsl r0, #12
mcr p15,0,r0,c7,c8,0 @ VA to PA translation with privileged read permission check
mrc p15,0,r0,c7,c4,0 @ read PA register
and r0, #1 @ failure bit
bx lr

16
exceptions/arm11/source/mainHandler.c
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@@ -63,10 +63,12 @@ void __attribute__((noreturn)) mainHandler(u32 regs[REG_DUMP_SIZE / 4], u32 type
for(u32 i = 0; i < 7; i++) registerDump[8 + i] = regs[8 + i];
for(u32 i = 0; i < 8; i++) registerDump[i] = regs[15 + i];
dumpHeader.stackDumpSize = 0x1000 - (registerDump[13] & 0xfff);
dumpHeader.stackDumpSize = 0x1000 - (registerDump[13] & 0xFFF);
//Dump code
vu8 *instr = (vu8 *)pc + ((cpsr & 0x20) ? 2 : 4) - dumpHeader.codeDumpSize; //Doesn't work well on 32-bit Thumb instructions, but it isn't much of a problem
if(cannotAccessVA((u8 *)instr) || cannotAccessVA((u8 *)instr + dumpHeader.codeDumpSize))
dumpHeader.codeDumpSize = 0;
for(u32 i = 0; i < dumpHeader.codeDumpSize; i++)
codeDump[i] = instr[i];
@@ -81,13 +83,17 @@ void __attribute__((noreturn)) mainHandler(u32 regs[REG_DUMP_SIZE / 4], u32 type
//Dump stack in place
vu32 *sp = (vu32 *)registerDump[13];
if(cannotAccessVA((u8 *)sp))
dumpHeader.stackDumpSize = 0;
for(u32 i = 0; i < dumpHeader.stackDumpSize / 4; i++)
*final++ = sp[i];
vu8 *currentKProcess = *(vu8 **)0xFFFF9004;
vu8 *currentKCodeSet = (currentKProcess != NULL) ? *(vu8 **)(currentKProcess + CODESET_OFFSET) : NULL;
if(currentKCodeSet != NULL)
vu8 *currentKProcess = (cannotAccessVA((u8 *)0xFFFF9004)) ? NULL : *(vu8 **)0xFFFF9004;
vu8 *currentKCodeSet = (currentKProcess != NULL && ((u32)currentKProcess & 3) == 0 && !cannotAccessVA((u8 *)currentKProcess + CODESET_OFFSET))
? *(vu8 **)(currentKProcess + CODESET_OFFSET) : NULL;
if(currentKCodeSet != NULL && ((u32)currentKCodeSet & 3) == 0 && !cannotAccessVA((u8 *)currentKCodeSet))
{
vu32 *additionalData = final;
dumpHeader.additionalDataSize = 16;
@@ -99,7 +105,7 @@ void __attribute__((noreturn)) mainHandler(u32 regs[REG_DUMP_SIZE / 4], u32 type
additionalData[3] = *(vu32 *)(currentKCodeSet + 0x60);
}
else
dumpHeader.additionalDataSize = 16;
dumpHeader.additionalDataSize = 0;
//Copy header (actually optimized by the compiler)
final = (vu32 *)FINAL_BUFFER;

6
exceptions/arm11/source/types.h
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@@ -23,7 +23,11 @@
#pragma once
#include <stdint.h>
#define NULL 0
#include <stdbool.h>
#ifndef NULL
#define NULL 0
#endif
//Common data types
typedef uint8_t u8;