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New debug feature: Use the SH1 user break controller to catch illegal memory accesses

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git-svn-id: svn://svn.rockbox.org/rockbox/trunk@5026 a1c6a512-1295-4272-9138-f99709370657
This commit is contained in:
Jens Arnold 2004-08-30 19:52:45 +00:00
parent 56fd6f9316
commit 06cb237af6
7 changed files with 104 additions and 6 deletions
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48
firmware/system.c
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@ -315,7 +315,7 @@ void system_reboot (void)
ICR = 0;
asm volatile ("jmp @%0; mov.l @%1,r15" : :
"r"(*(int*)0),"r"(4));
"r"(*(int*)0),"r"(4));
}
void UIE (unsigned int pc) /* Unexpected Interrupt or Exception */
@ -498,4 +498,50 @@ void system_init(void)
WCR1 = 0x4000; /* Long wait states for CS6 (ATA), short for the rest. */
WCR3 = 0x8000; /* WAIT is pulled up, 1 state inserted for CS6 */
#endif
}
/* Utilize the user break controller to catch invalid memory accesses. */
int system_memory_guard(int newmode)
{
static const struct {
unsigned long addr;
unsigned long mask;
unsigned short bbr;
} modes[MAXMEMGUARD] = {
/* catch nothing */
{ 0x00000000, 0x00000000, 0x0000 },
/* catch writes to area 02 (flash ROM) */
{ 0x02000000, 0x00FFFFFF, 0x00F8 },
/* catch all accesses to areas 00 (internal ROM) and 01 (free) */
{ 0x00000000, 0x01FFFFFF, 0x00FC }
};
int oldmode = MEMGUARD_NONE;
int i;
/* figure out the old mode from what is in the UBC regs. If the register
values don't match any mode, assume MEMGUARD_NONE */
for (i = MEMGUARD_NONE; i < MAXMEMGUARD; i++)
{
if (BAR == modes[i].addr && BAMR == modes[i].mask &&
BBR == modes[i].bbr)
{
oldmode = i;
break;
}
}
if (newmode == MEMGUARD_KEEP)
newmode = oldmode;
BBR = 0; /* switch off everything first */
/* always set the UBC according to the mode, in case the old settings
didn't match any valid mode */
BAR = modes[newmode].addr;
BAMR = modes[newmode].mask;
BBR = modes[newmode].bbr;
return oldmode;
}