Commit 37f5d61a authored by Will Deacon's avatar Will Deacon
Browse files

Merge branch 'for-next/kprobes' into for-next/core 

* for-next/kprobes:
  arm64: kprobes: Return DBG_HOOK_ERROR if kprobes can not handle a BRK
  arm64: kprobes: Let arch do_page_fault() fix up page fault in user handler
  arm64: Prohibit instrumentation on arch_stack_walk()
parents 926939c7 3b84efc0

arch/arm64/kernel/probes/kprobes.c

+36 −50
Original line number Diff line number Diff line
@@ -294,19 +294,12 @@ int __kprobes kprobe_fault_handler(struct pt_regs *regs, unsigned int fsr) 
		}



		break;

	case KPROBE_HIT_ACTIVE:

	case KPROBE_HIT_SSDONE:

		/*

		 * In case the user-specified fault handler returned

		 * zero, try to fix up.

		 */

		if (fixup_exception(regs))

			return 1;

	}

	return 0;

}



static void __kprobes kprobe_handler(struct pt_regs *regs)

static int __kprobes

kprobe_breakpoint_handler(struct pt_regs *regs, unsigned long esr)

{

	struct kprobe *p, *cur_kprobe;

	struct kprobe_ctlblk *kcb;
@@ -316,11 +309,18 @@ static void __kprobes kprobe_handler(struct pt_regs *regs) 
	cur_kprobe = kprobe_running();



	p = get_kprobe((kprobe_opcode_t *) addr);

	if (WARN_ON_ONCE(!p)) {

		/*

		 * Something went wrong. This BRK used an immediate reserved

		 * for kprobes, but we couldn't find any corresponding probe.

		 */

		return DBG_HOOK_ERROR;

	}



	if (p) {

	if (cur_kprobe) {

			if (reenter_kprobe(p, regs, kcb))

				return;

		/* Hit a kprobe inside another kprobe */

		if (!reenter_kprobe(p, regs, kcb))

			return DBG_HOOK_ERROR;

	} else {

		/* Probe hit */

		set_current_kprobe(p);
@@ -330,25 +330,23 @@ static void __kprobes kprobe_handler(struct pt_regs *regs) 
		 * If we have no pre-handler or it returned 0, we

		 * continue with normal processing.  If we have a

		 * pre-handler and it returned non-zero, it will

			 * modify the execution path and no need to single

			 * stepping. Let's just reset current kprobe and exit.

		 * modify the execution path and not need to single-step

		 * Let's just reset current kprobe and exit.

		 */

			if (!p->pre_handler || !p->pre_handler(p, regs)) {

		if (!p->pre_handler || !p->pre_handler(p, regs))

			setup_singlestep(p, regs, kcb, 0);

			} else

		else

			reset_current_kprobe();

	}

	}

	/*

	 * The breakpoint instruction was removed right

	 * after we hit it.  Another cpu has removed

	 * either a probepoint or a debugger breakpoint

	 * at this address.  In either case, no further

	 * handling of this interrupt is appropriate.

	 * Return back to original instruction, and continue.

	 */



	return DBG_HOOK_HANDLED;

}



static struct break_hook kprobes_break_hook = {

	.imm = KPROBES_BRK_IMM,

	.fn = kprobe_breakpoint_handler,

};



static int __kprobes

kprobe_breakpoint_ss_handler(struct pt_regs *regs, unsigned long esr)

{
@@ -373,18 +371,6 @@ static struct break_hook kprobes_break_ss_hook = { 
	.fn = kprobe_breakpoint_ss_handler,

};



static int __kprobes

kprobe_breakpoint_handler(struct pt_regs *regs, unsigned long esr)

{

	kprobe_handler(regs);

	return DBG_HOOK_HANDLED;

}



static struct break_hook kprobes_break_hook = {

	.imm = KPROBES_BRK_IMM,

	.fn = kprobe_breakpoint_handler,

};



/*

 * Provide a blacklist of symbols identifying ranges which cannot be kprobed.

 * This blacklist is exposed to userspace via debugfs (kprobes/blacklist).

arch/arm64/kernel/stacktrace.c

+5 −5
Original line number Diff line number Diff line
@@ -23,7 +23,7 @@ 
 *

 * The regs must be on a stack currently owned by the calling task.

 */

static inline void unwind_init_from_regs(struct unwind_state *state,

static __always_inline void unwind_init_from_regs(struct unwind_state *state,

						  struct pt_regs *regs)

{

	unwind_init_common(state, current);
@@ -58,7 +58,7 @@ static __always_inline void unwind_init_from_caller(struct unwind_state *state) 
 * duration of the unwind, or the unwind will be bogus. It is never valid to

 * call this for the current task.

 */

static inline void unwind_init_from_task(struct unwind_state *state,

static __always_inline void unwind_init_from_task(struct unwind_state *state,

						  struct task_struct *task)

{

	unwind_init_common(state, task);
@@ -186,7 +186,7 @@ void show_stack(struct task_struct *tsk, unsigned long *sp, const char *loglvl) 
			: stackinfo_get_unknown();		\

	})



noinline notrace void arch_stack_walk(stack_trace_consume_fn consume_entry,

noinline noinstr void arch_stack_walk(stack_trace_consume_fn consume_entry,

			      void *cookie, struct task_struct *task,

			      struct pt_regs *regs)

{