static struct pt_regs *get_user_regs(struct task_struct *tsk)
{
- return (struct pt_regs *)((unsigned long) tsk->thread_info +
+ return (struct pt_regs *)((unsigned long)task_stack_page(tsk) +
THREAD_SIZE - sizeof(struct pt_regs));
}
-static void ptrace_single_step(struct task_struct *tsk)
+static void user_enable_single_step(struct task_struct *tsk)
{
- pr_debug("ptrace_single_step: pid=%u, SR=0x%08lx\n",
- tsk->pid, tsk->thread.cpu_context.sr);
- if (!(tsk->thread.cpu_context.sr & SR_D)) {
- /*
- * Set a breakpoint at the current pc to force the
- * process into debug mode. The syscall/exception
- * exit code will set a breakpoint at the return
- * address when this flag is set.
- */
- pr_debug("ptrace_single_step: Setting TIF_BREAKPOINT\n");
- set_tsk_thread_flag(tsk, TIF_BREAKPOINT);
- }
+ pr_debug("user_enable_single_step: pid=%u, PC=0x%08lx, SR=0x%08lx\n",
+ tsk->pid, task_pt_regs(tsk)->pc, task_pt_regs(tsk)->sr);
- /* The monitor code will do the actual step for us */
+ /*
+ * We can't schedule in Debug mode, so when TIF_BREAKPOINT is
+ * set, the system call or exception handler will do a
+ * breakpoint to enter monitor mode before returning to
+ * userspace.
+ *
+ * The monitor code will then notice that TIF_SINGLE_STEP is
+ * set and return to userspace with single stepping enabled.
+ * The CPU will then enter monitor mode again after exactly
+ * one instruction has been executed, and the monitor code
+ * will then send a SIGTRAP to the process.
+ */
+ set_tsk_thread_flag(tsk, TIF_BREAKPOINT);
set_tsk_thread_flag(tsk, TIF_SINGLE_STEP);
}
+void user_disable_single_step(struct task_struct *child)
+{
+ /* XXX(hch): a no-op here seems wrong.. */
+}
+
/*
* Called by kernel/ptrace.c when detaching
*
void ptrace_disable(struct task_struct *child)
{
clear_tsk_thread_flag(child, TIF_SINGLE_STEP);
-}
-
-/*
- * Handle hitting a breakpoint
- */
-static void ptrace_break(struct task_struct *tsk, struct pt_regs *regs)
-{
- siginfo_t info;
-
- info.si_signo = SIGTRAP;
- info.si_errno = 0;
- info.si_code = TRAP_BRKPT;
- info.si_addr = (void __user *)instruction_pointer(regs);
-
- pr_debug("ptrace_break: Sending SIGTRAP to PID %u (pc = 0x%p)\n",
- tsk->pid, info.si_addr);
- force_sig_info(SIGTRAP, &info, tsk);
+ clear_tsk_thread_flag(child, TIF_BREAKPOINT);
+ ocd_disable(child);
}
/*
unsigned long *regs;
unsigned long value;
- pr_debug("ptrace_read_user(%p, %#lx, %p)\n",
- tsk, offset, data);
-
if (offset & 3 || offset >= sizeof(struct user)) {
printk("ptrace_read_user: invalid offset 0x%08lx\n", offset);
return -EIO;
if (offset < sizeof(struct pt_regs))
value = regs[offset / sizeof(regs[0])];
+ pr_debug("ptrace_read_user(%s[%u], %#lx, %p) -> %#lx\n",
+ tsk->comm, tsk->pid, offset, data, value);
+
return put_user(value, data);
}
{
unsigned long *regs;
+ pr_debug("ptrace_write_user(%s[%u], %#lx, %#lx)\n",
+ tsk->comm, tsk->pid, offset, value);
+
if (offset & 3 || offset >= sizeof(struct user)) {
- printk("ptrace_write_user: invalid offset 0x%08lx\n", offset);
+ pr_debug(" invalid offset 0x%08lx\n", offset);
return -EIO;
}
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;
+ ret = generic_ptrace_peekdata(child, addr, data);
break;
case PTRACE_PEEKUSR:
/* 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;
+ ret = generic_ptrace_pokedata(child, addr, data);
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;
break;
}
- pr_debug("sys_ptrace returning %d (DC = 0x%08lx)\n", ret, __mfdr(DBGREG_DC));
return ret;
}
asmlinkage void syscall_trace(void)
{
- pr_debug("syscall_trace called\n");
if (!test_thread_flag(TIF_SYSCALL_TRACE))
return;
if (!(current->ptrace & PT_PTRACED))
return;
- pr_debug("syscall_trace: notifying parent\n");
/* The 0x80 provides a way for the tracing parent to
* distinguish between a syscall stop and SIGTRAP delivery */
ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
}
}
-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, "ptrace", regs, 0, 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);
- }
-}
-
/*
- * Handle breakpoints, single steps and other debuggy things. To keep
- * things simple initially, we run with interrupts and exceptions
- * disabled all the time.
+ * debug_trampoline() is an assembly stub which will store all user
+ * registers on the stack and execute a breakpoint instruction.
+ *
+ * If we single-step into an exception handler which runs with
+ * interrupts disabled the whole time so it doesn't have to check for
+ * pending work, its return address will be modified so that it ends
+ * up returning to debug_trampoline.
+ *
+ * If the exception handler decides to store the user context and
+ * enable interrupts after all, it will restore the original return
+ * address and status register value. Before it returns, it will
+ * notice that TIF_BREAKPOINT is set and execute a breakpoint
+ * instruction.
*/
-asmlinkage void do_debug(struct pt_regs *regs)
-{
- unsigned long dc, ds;
+extern void debug_trampoline(void);
- ds = __mfdr(DBGREG_DS);
- pr_debug("do_debug: pc = %08lx, ds = %08lx\n", regs->pc, ds);
+asmlinkage struct pt_regs *do_debug(struct pt_regs *regs)
+{
+ struct thread_info *ti;
+ unsigned long trampoline_addr;
+ u32 status;
+ u32 ctrl;
+ int code;
+
+ status = ocd_read(DS);
+ ti = current_thread_info();
+ code = TRAP_BRKPT;
+
+ pr_debug("do_debug: status=0x%08x PC=0x%08lx SR=0x%08lx tif=0x%08lx\n",
+ status, regs->pc, regs->sr, ti->flags);
+
+ if (!user_mode(regs)) {
+ unsigned long die_val = DIE_BREAKPOINT;
+
+ if (status & (1 << OCD_DS_SSS_BIT))
+ die_val = DIE_SSTEP;
+
+ if (notify_die(die_val, "ptrace", regs, 0, 0, SIGTRAP)
+ == NOTIFY_STOP)
+ return regs;
+
+ if ((status & (1 << OCD_DS_SWB_BIT))
+ && test_and_clear_ti_thread_flag(
+ ti, TIF_BREAKPOINT)) {
+ /*
+ * Explicit breakpoint from trampoline or
+ * exception/syscall/interrupt handler.
+ *
+ * The real saved regs are on the stack right
+ * after the ones we saved on entry.
+ */
+ regs++;
+ pr_debug(" -> TIF_BREAKPOINT done, adjusted regs:"
+ "PC=0x%08lx SR=0x%08lx\n",
+ regs->pc, regs->sr);
+ BUG_ON(!user_mode(regs));
+
+ if (test_thread_flag(TIF_SINGLE_STEP)) {
+ pr_debug("Going to do single step...\n");
+ return regs;
+ }
+
+ /*
+ * No TIF_SINGLE_STEP means we're done
+ * stepping over a syscall. Do the trap now.
+ */
+ code = TRAP_TRACE;
+ } else if ((status & (1 << OCD_DS_SSS_BIT))
+ && test_ti_thread_flag(ti, TIF_SINGLE_STEP)) {
+
+ pr_debug("Stepped into something, "
+ "setting TIF_BREAKPOINT...\n");
+ set_ti_thread_flag(ti, TIF_BREAKPOINT);
+
+ /*
+ * We stepped into an exception, interrupt or
+ * syscall handler. Some exception handlers
+ * don't check for pending work, so we need to
+ * set up a trampoline just in case.
+ *
+ * The exception entry code will undo the
+ * trampoline stuff if it does a full context
+ * save (which also means that it'll check for
+ * pending work later.)
+ */
+ if ((regs->sr & MODE_MASK) == MODE_EXCEPTION) {
+ trampoline_addr
+ = (unsigned long)&debug_trampoline;
+
+ pr_debug("Setting up trampoline...\n");
+ ti->rar_saved = sysreg_read(RAR_EX);
+ ti->rsr_saved = sysreg_read(RSR_EX);
+ sysreg_write(RAR_EX, trampoline_addr);
+ sysreg_write(RSR_EX, (MODE_EXCEPTION
+ | SR_EM | SR_GM));
+ BUG_ON(ti->rsr_saved & MODE_MASK);
+ }
+
+ /*
+ * If we stepped into a system call, we
+ * shouldn't do a single step after we return
+ * since the return address is right after the
+ * "scall" instruction we were told to step
+ * over.
+ */
+ if ((regs->sr & MODE_MASK) == MODE_SUPERVISOR) {
+ pr_debug("Supervisor; no single step\n");
+ clear_ti_thread_flag(ti, TIF_SINGLE_STEP);
+ }
+
+ ctrl = ocd_read(DC);
+ ctrl &= ~(1 << OCD_DC_SS_BIT);
+ ocd_write(DC, ctrl);
+
+ return regs;
+ } else {
+ printk(KERN_ERR "Unexpected OCD_DS value: 0x%08x\n",
+ status);
+ printk(KERN_ERR "Thread flags: 0x%08lx\n", ti->flags);
+ die("Unhandled debug trap in kernel mode",
+ regs, SIGTRAP);
+ }
+ } else if (status & (1 << OCD_DS_SSS_BIT)) {
+ /* Single step in user mode */
+ code = TRAP_TRACE;
- 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);
+ ctrl = ocd_read(DC);
+ ctrl &= ~(1 << OCD_DC_SS_BIT);
+ ocd_write(DC, ctrl);
}
- 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);
+ pr_debug("Sending SIGTRAP: code=%d PC=0x%08lx SR=0x%08lx\n",
+ code, regs->pc, regs->sr);
- clear_thread_flag(TIF_SINGLE_STEP);
- ptrace_break(current, regs);
- }
- } else {
- /* regular breakpoint */
- ptrace_break(current, regs);
- }
+ clear_thread_flag(TIF_SINGLE_STEP);
+ _exception(SIGTRAP, regs, code, instruction_pointer(regs));
+
+ return regs;
}
Code Review / linux-2.6.git / blobdiff