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Prevent double faults when either PC or SP is invalid

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This commit is contained in:
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;

4
exceptions/arm11/source/types.h
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@ -23,7 +23,11 @@
#pragma once
#include <stdint.h>
#include <stdbool.h>
#ifndef NULL
#define NULL 0
#endif
//Common data types
typedef uint8_t u8;

1
exceptions/arm9/source/handlers.h
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@ -23,6 +23,7 @@
#pragma once
#include "types.h"
u32 readMPUConfig(u32 regionSettings[8]);
void FIQHandler(void);
void undefinedInstructionHandler(void);
void dataAbortHandler(void);

17
exceptions/arm9/source/handlers.s
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@ -62,3 +62,20 @@ GEN_HANDLER FIQHandler
GEN_HANDLER undefinedInstructionHandler
GEN_HANDLER prefetchAbortHandler
GEN_HANDLER dataAbortHandler
.global readMPUConfig
.type readMPUConfig, %function
readMPUConfig:
stmfd sp!, {r4-r8}
mrc p15,0,r1,c6,c0,0
mrc p15,0,r2,c6,c1,0
mrc p15,0,r3,c6,c2,0
mrc p15,0,r4,c6,c3,0
mrc p15,0,r5,c6,c4,0
mrc p15,0,r6,c6,c5,0
mrc p15,0,r7,c6,c6,0
mrc p15,0,r8,c6,c7,0
stmia r0, {r1-r8}
mrc p15,0,r0,c5,c0,2 @ read data access permission bits
ldmfd sp!, {r4-r8}
bx lr

29
exceptions/arm9/source/mainHandler.c
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@ -28,6 +28,29 @@
#define REG_DUMP_SIZE (4*17)
#define CODE_DUMP_SIZE 48
bool cannotAccessAddress(const void *address)
{
u32 regionSettings[8];
u32 addr = (u32)address;
u32 dataAccessPermissions = readMPUConfig(regionSettings);
for(u32 i = 0; i < 8; i++)
{
if((dataAccessPermissions & 0xF) == 0 || (regionSettings[i] & 1) == 0)
continue; //no access / region not enabled
u32 regionAddrBase = regionSettings[i] & ~0xFFF;
u32 regionSize = 1 << (((regionSettings[i] >> 1) & 0x1F) + 1);
if(addr >= regionAddrBase && addr < regionAddrBase + regionSize)
return false;
dataAccessPermissions >>= 4;
}
return true;
}
void __attribute__((noreturn)) mainHandler(u32 regs[REG_DUMP_SIZE / 4], u32 type)
{
ExceptionDumpHeader dumpHeader;
@ -58,11 +81,13 @@ void __attribute__((noreturn)) mainHandler(u32 regs[REG_DUMP_SIZE / 4], u32 type
for(u32 i = 0; i < 7; i++) registerDump[8 + i] = regs[2 + i];
for(u32 i = 0; i < 8; i++) registerDump[i] = regs[9 + i];
dumpHeader.stackDumpSize = 0x1000 - (registerDump[13] & 0xfff);
dumpHeader.stackDumpSize = 0x1000 - (registerDump[13] & 0xFFF);
dumpHeader.totalSize = sizeof(ExceptionDumpHeader) + dumpHeader.registerDumpSize + dumpHeader.codeDumpSize + dumpHeader.stackDumpSize;
//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(cannotAccessAddress((u8 *)instr) || cannotAccessAddress((u8 *)instr + dumpHeader.codeDumpSize))
dumpHeader.codeDumpSize = 0;
for(u32 i = 0; i < dumpHeader.codeDumpSize; i++)
codeDump[i] = instr[i];
@ -79,6 +104,8 @@ void __attribute__((noreturn)) mainHandler(u32 regs[REG_DUMP_SIZE / 4], u32 type
//Dump stack in place
vu32 *sp = (vu32 *)registerDump[13];
if(cannotAccessAddress((u8 *)sp))
dumpHeader.stackDumpSize = 0;
for(u32 i = 0; i < dumpHeader.stackDumpSize / 4; i++)
*final++ = sp[i];

5
exceptions/arm9/source/types.h
View File

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

2
exceptions/exception_dump_parser.py
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@ -114,7 +114,7 @@ if __name__ == "__main__":
else: print("Processor: ARM11 (core {0})".format(processor >> 16))
typeDetailsStr = ""
if exceptionType == 2 and (registers[16] & 0x20) == 0 and unpack_from("<I", codeDump[-4:])[0] == 0xe12fff7f:
if exceptionType == 2 and (registers[16] & 0x20) == 0 and codeDumpSize >= 4 and unpack_from("<I", codeDump[-4:])[0] == 0xe12fff7f:
typeDetailsStr = " " + (svcBreakReasons[registers[0]] if registers[0] < 3 else "(svcBreak)")
elif processor != 9 and (registers[20] & 0x80000000) != 0:
typeDetailsStr = " (VFP exception)"