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Commit 26c6ccdf authored by Frederic Weisbecker's avatar Frederic Weisbecker Committed by Ingo Molnar
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perf/hw_breakpoint: Clean up and consolidate modify_user_hw_breakpoint_check() 



Remove the dance around old and new attributes. Just don't modify the
previous breakpoint at all until we have verified everything.

Original-patch-by: default avatarAndy Lutomirski <luto@kernel.org>
Reported-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: default avatarFrederic Weisbecker <frederic@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Joel Fernandes <joel.opensrc@gmail.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rich Felker <dalias@libc.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Link: http://lkml.kernel.org/r/1529981939-8231-13-git-send-email-frederic@kernel.org


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent cb8b7881

kernel/events/hw_breakpoint.c

+25 −19
Original line number Diff line number Diff line
@@ -461,37 +461,43 @@ register_user_hw_breakpoint(struct perf_event_attr *attr, 
}

EXPORT_SYMBOL_GPL(register_user_hw_breakpoint);



static void hw_breakpoint_copy_attr(struct perf_event_attr *to,

				    struct perf_event_attr *from)

{

	to->bp_addr = from->bp_addr;

	to->bp_type = from->bp_type;

	to->bp_len  = from->bp_len;

	to->disabled = from->disabled;

}



int

modify_user_hw_breakpoint_check(struct perf_event *bp, struct perf_event_attr *attr,

			        bool check)

{

	u64 old_addr = bp->attr.bp_addr;

	u64 old_len  = bp->attr.bp_len;

	int old_type = bp->attr.bp_type;

	bool modify  = attr->bp_type != old_type;

	struct arch_hw_breakpoint hw;

	int err = 0;

	int err;



	bp->attr.bp_addr = attr->bp_addr;

	bp->attr.bp_type = attr->bp_type;

	bp->attr.bp_len  = attr->bp_len;

	err = hw_breakpoint_parse(bp, attr, &hw);

	if (err)

		return err;



	if (check && memcmp(&bp->attr, attr, sizeof(*attr)))

		return -EINVAL;

	if (check) {

		struct perf_event_attr old_attr;



	err = hw_breakpoint_parse(bp, attr, &hw);

	if (!err && modify)

		err = modify_bp_slot(bp, old_type, bp->attr.bp_type);

		old_attr = bp->attr;

		hw_breakpoint_copy_attr(&old_attr, attr);

		if (memcmp(&old_attr, attr, sizeof(*attr)))

			return -EINVAL;

	}



	if (err) {

		bp->attr.bp_addr = old_addr;

		bp->attr.bp_type = old_type;

		bp->attr.bp_len  = old_len;

	if (bp->attr.bp_type != attr->bp_type) {

		err = modify_bp_slot(bp, bp->attr.bp_type, attr->bp_type);

		if (err)

			return err;

	}



	hw_breakpoint_copy_attr(&bp->attr, attr);

	bp->hw.info = hw;

	bp->attr.disabled = attr->disabled;



	return 0;

}