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Commit 9afe33ad authored by Oleg Nesterov's avatar Oleg Nesterov Committed by Linus Torvalds
Browse files

ptrace/x86: introduce ptrace_register_breakpoint() 



No functional changes, preparation.

Extract the "register breakpoint" code from ptrace_get_debugreg() into
the new/generic helper, ptrace_register_breakpoint().  It will have more
users.

The patch also adds another simple helper, ptrace_fill_bp_fields(), to
factor out the arch_bp_generic_fields() logic in register/modify.

Signed-off-by: default avatarOleg Nesterov <oleg@redhat.com>
Acked-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jan Kratochvil <jan.kratochvil@redhat.com>
Cc: Michael Neuling <mikey@neuling.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Prasad <prasad@linux.vnet.ibm.com>
Cc: Russell King <linux@arm.linux.org.uk>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 29a55513

arch/x86/kernel/ptrace.c

+50 −36
Original line number Original line Diff line number Diff line
@@ -601,22 +601,48 @@ static unsigned long ptrace_get_dr7(struct perf_event *bp[]) 
	return dr7;

	return dr7;

}

}





static int

static int ptrace_fill_bp_fields(struct perf_event_attr *attr,

ptrace_modify_breakpoint(struct perf_event *bp, int len, int type,

					int len, int type, bool disabled)

			 struct task_struct *tsk, int disabled)

{

	int err, bp_len, bp_type;



	err = arch_bp_generic_fields(len, type, &bp_len, &bp_type);

	if (!err) {

		attr->bp_len = bp_len;

		attr->bp_type = bp_type;

		attr->disabled = disabled;

	}



	return err;

}



static struct perf_event *

ptrace_register_breakpoint(struct task_struct *tsk, int len, int type,

				unsigned long addr, bool disabled)

{

{

	int err;

	int gen_len, gen_type;

	struct perf_event_attr attr;

	struct perf_event_attr attr;

	int err;





	err = arch_bp_generic_fields(len, type, &gen_len, &gen_type);

	ptrace_breakpoint_init(&attr);

	attr.bp_addr = addr;



	err = ptrace_fill_bp_fields(&attr, len, type, disabled);

	if (err)

	if (err)

		return err;

		return ERR_PTR(err);





	attr = bp->attr;

	return register_user_hw_breakpoint(&attr, ptrace_triggered,

	attr.bp_len = gen_len;

						 NULL, tsk);

	attr.bp_type = gen_type;

}

	attr.disabled = disabled;



static int ptrace_modify_breakpoint(struct perf_event *bp, int len, int type,

					int disabled)

{

	struct perf_event_attr attr = bp->attr;

	int err;



	err = ptrace_fill_bp_fields(&attr, len, type, disabled);

	if (err)

		return err;





	return modify_user_hw_breakpoint(bp, &attr);

	return modify_user_hw_breakpoint(bp, &attr);

}

}
@@ -653,7 +679,7 @@ static int ptrace_write_dr7(struct task_struct *tsk, unsigned long data) 
			break;

			break;

		}

		}





		rc = ptrace_modify_breakpoint(bp, len, type, tsk, disabled);

		rc = ptrace_modify_breakpoint(bp, len, type, disabled);

		if (rc)

		if (rc)

			break;

			break;

	}

	}
@@ -693,26 +719,14 @@ static unsigned long ptrace_get_debugreg(struct task_struct *tsk, int n) 
static int ptrace_set_breakpoint_addr(struct task_struct *tsk, int nr,

static int ptrace_set_breakpoint_addr(struct task_struct *tsk, int nr,

				      unsigned long addr)

				      unsigned long addr)

{

{

	struct perf_event *bp;

	struct thread_struct *t = &tsk->thread;

	struct thread_struct *t = &tsk->thread;

	struct perf_event_attr attr;

	struct perf_event *bp = t->ptrace_bps[nr];

	int err = 0;

	int err = 0;





	if (!t->ptrace_bps[nr]) {

	if (!bp) {

		ptrace_breakpoint_init(&attr);

		/*

		 * Put stub len and type to register (reserve) an inactive but

		 * correct bp

		 */

		attr.bp_addr = addr;

		attr.bp_len = HW_BREAKPOINT_LEN_1;

		attr.bp_type = HW_BREAKPOINT_W;

		attr.disabled = 1;



		bp = register_user_hw_breakpoint(&attr, ptrace_triggered,

						 NULL, tsk);



		/*

		/*

		 * Put stub len and type to create an inactive but correct bp.

		 *

		 * CHECKME: the previous code returned -EIO if the addr wasn't

		 * CHECKME: the previous code returned -EIO if the addr wasn't

		 * a valid task virtual addr. The new one will return -EINVAL in

		 * a valid task virtual addr. The new one will return -EINVAL in

		 *  this case.

		 *  this case.
@@ -721,20 +735,20 @@ static int ptrace_set_breakpoint_addr(struct task_struct *tsk, int nr, 
		 * writing for the user. And anyway this is the previous

		 * writing for the user. And anyway this is the previous

		 * behaviour.

		 * behaviour.

		 */

		 */

		if (IS_ERR(bp)) {

		bp = ptrace_register_breakpoint(tsk,

				X86_BREAKPOINT_LEN_1, X86_BREAKPOINT_WRITE,

				addr, true);

		if (IS_ERR(bp))

			err = PTR_ERR(bp);

			err = PTR_ERR(bp);

			goto out;

		else

		}



			t->ptrace_bps[nr] = bp;

			t->ptrace_bps[nr] = bp;

	} else {

	} else {

		bp = t->ptrace_bps[nr];

		struct perf_event_attr attr = bp->attr;





		attr = bp->attr;

		attr.bp_addr = addr;

		attr.bp_addr = addr;

		err = modify_user_hw_breakpoint(bp, &attr);

		err = modify_user_hw_breakpoint(bp, &attr);

	}

	}

out:



	return err;

	return err;

}

}