/*
* Handle breakpoints, single steps and other debuggy things. To keep
* things simple initially, we run with interrupts and exceptions
* disabled all the time.
*/
asmlinkage void do_debug(struct pt_regs *regs)
{
unsigned long dc, ds;
ds = __mfdr(DBGREG_DS);
pr_debug("do_debug: pc = %08lx, ds = %08lx\n", regs->pc, ds);
if (test_thread_flag(TIF_BREAKPOINT)) {
pr_debug("TIF_BREAKPOINT set\n");
/* We're taking care of it */
clear_thread_flag(TIF_BREAKPOINT);
__mtdr(DBGREG_BWC2A, 0);
}
if (test_thread_flag(TIF_SINGLE_STEP)) {
pr_debug("TIF_SINGLE_STEP set, ds = 0x%08lx\n", ds);
if (ds & DS_SSS) {
dc = __mfdr(DBGREG_DC);
dc &= ~DC_SS;
__mtdr(DBGREG_DC, dc);
clear_thread_flag(TIF_SINGLE_STEP);
ptrace_break(current, regs);
}
} else {
/* regular breakpoint */
ptrace_break(current, regs);
}
}
asmlinkage void do_debug_priv(struct pt_regs *regs)
{
unsigned long dc, ds;
unsigned long die_val;
ds = __mfdr(DBGREG_DS);
pr_debug("do_debug_priv: pc = %08lx, ds = %08lx\n", regs->pc, ds);
if (ds & DS_SSS)
die_val = DIE_SSTEP;
else
die_val = DIE_BREAKPOINT;
if (notify_die(die_val, regs, 0, SIGTRAP) == NOTIFY_STOP)
return;
if (likely(ds & DS_SSS)) {
extern void itlb_miss(void);
extern void tlb_miss_common(void);
struct thread_info *ti;
dc = __mfdr(DBGREG_DC);
dc &= ~DC_SS;
__mtdr(DBGREG_DC, dc);
ti = current_thread_info();
set_ti_thread_flag(ti, TIF_BREAKPOINT);
/* The TLB miss handlers don't check thread flags */
if ((regs->pc >= (unsigned long)&itlb_miss)
&& (regs->pc <= (unsigned long)&tlb_miss_common)) {
__mtdr(DBGREG_BWA2A, sysreg_read(RAR_EX));
__mtdr(DBGREG_BWC2A, 0x40000001 | (get_asid() << 1));
}
/*
* If we're running in supervisor mode, the breakpoint
* will take us where we want directly, no need to
* single step.
*/
if ((regs->sr & MODE_MASK) != MODE_SUPERVISOR)
set_ti_thread_flag(ti, TIF_SINGLE_STEP);
} else {
panic("Unable to handle debug trap at pc = %08lx\n",
regs->pc);
}
}
int __init arch_init_kprobes(void)
{
printk("KPROBES: Enabling monitor mode (MM|DBE)...\n");
__mtdr(DBGREG_DC, DC_MM | DC_DBE);
/* TODO: Register kretprobe trampoline */
return 0;
}
static void __kprobes resume_execution(struct kprobe *p, struct pt_regs *regs)
{
unsigned long dc;
pr_debug("resuming execution at PC=%08lx\n", regs->pc);
dc = __mfdr(DBGREG_DC);
dc &= ~DC_SS;
__mtdr(DBGREG_DC, dc);
*p->addr = BREAKPOINT_INSTRUCTION;
flush_icache_range((unsigned long)p->addr,
(unsigned long)p->addr + sizeof(kprobe_opcode_t));
}
static void __kprobes prepare_singlestep(struct kprobe *p, struct pt_regs *regs)
{
unsigned long dc;
pr_debug("preparing to singlestep over %p (PC=%08lx)\n",
p->addr, regs->pc);
BUG_ON(!(sysreg_read(SR) & SYSREG_BIT(SR_D)));
dc = __mfdr(DBGREG_DC);
dc |= DC_SS;
__mtdr(DBGREG_DC, dc);
/*
* We must run the instruction from its original location
* since it may actually reference PC.
*
* TODO: Do the instruction replacement directly in icache.
*/
*p->addr = p->opcode;
flush_icache_range((unsigned long)p->addr,
(unsigned long)p->addr + sizeof(kprobe_opcode_t));
}
long arch_ptrace(struct task_struct *child, long request, long addr, long data)
{
unsigned long tmp;
int ret;
pr_debug("arch_ptrace(%ld, %d, %#lx, %#lx)\n",
request, child->pid, addr, data);
pr_debug("ptrace: Enabling monitor mode...\n");
__mtdr(DBGREG_DC, __mfdr(DBGREG_DC) | DC_MM | DC_DBE);
switch (request) {
/* Read the word at location addr in the child process */
case PTRACE_PEEKTEXT:
case PTRACE_PEEKDATA:
ret = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
if (ret == sizeof(tmp))
ret = put_user(tmp, (unsigned long __user *)data);
else
ret = -EIO;
break;
case PTRACE_PEEKUSR:
ret = ptrace_read_user(child, addr,
(unsigned long __user *)data);
break;
/* Write the word in data at location addr */
case PTRACE_POKETEXT:
case PTRACE_POKEDATA:
ret = access_process_vm(child, addr, &data, sizeof(data), 1);
if (ret == sizeof(data))
ret = 0;
else
ret = -EIO;
break;
case PTRACE_POKEUSR:
ret = ptrace_write_user(child, addr, data);
break;
/* continue and stop at next (return from) syscall */
case PTRACE_SYSCALL:
/* restart after signal */
case PTRACE_CONT:
ret = -EIO;
if (!valid_signal(data))
break;
if (request == PTRACE_SYSCALL)
set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
else
clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
child->exit_code = data;
/* XXX: Are we sure no breakpoints are active here? */
wake_up_process(child);
ret = 0;
break;
/*
* Make the child exit. Best I can do is send it a
* SIGKILL. Perhaps it should be put in the status that it
* wants to exit.
*/
case PTRACE_KILL:
ret = 0;
if (child->exit_state == EXIT_ZOMBIE)
break;
child->exit_code = SIGKILL;
wake_up_process(child);
break;
/*
* execute single instruction.
*/
case PTRACE_SINGLESTEP:
ret = -EIO;
if (!valid_signal(data))
break;
clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
ptrace_single_step(child);
child->exit_code = data;
wake_up_process(child);
ret = 0;
break;
/* Detach a process that was attached */
case PTRACE_DETACH:
ret = ptrace_detach(child, data);
break;
case PTRACE_GETREGS:
ret = ptrace_getregs(child, (void __user *)data);
break;
case PTRACE_SETREGS:
ret = ptrace_setregs(child, (const void __user *)data);
break;
default:
ret = ptrace_request(child, request, addr, data);
break;
}
pr_debug("sys_ptrace returning %d (DC = 0x%08lx)\n", ret, __mfdr(DBGREG_DC));
return ret;
}
void machine_restart(char *cmd)
{
__mtdr(DBGREG_DC, DC_DBE);
__mtdr(DBGREG_DC, DC_RES);
while (1) ;
}
