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perf/hw_breakpoint: Clean up and consolidate modify_user_hw_breakpoint_check()

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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: Andy Lutomirski <luto@kernel.org>
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Frederic 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: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Frederic Weisbecker 2018-06-26 04:58:59 +02:00 committed by Ingo Molnar
parent cb8b78815b
commit 26c6ccdf5c
1 changed files with 26 additions and 20 deletions
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46
kernel/events/hw_breakpoint.c
View file

@ -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;
bp->attr.bp_addr = attr->bp_addr;
bp->attr.bp_type = attr->bp_type;
bp->attr.bp_len = attr->bp_len;
if (check && memcmp(&bp->attr, attr, sizeof(*attr)))
return -EINVAL;
int err;
err = hw_breakpoint_parse(bp, attr, &hw);
if (!err && modify)
err = modify_bp_slot(bp, old_type, bp->attr.bp_type);
if (err) {
bp->attr.bp_addr = old_addr;
bp->attr.bp_type = old_type;
bp->attr.bp_len = old_len;
if (err)
return err;
if (check) {
struct perf_event_attr old_attr;
old_attr = bp->attr;
hw_breakpoint_copy_attr(&old_attr, attr);
if (memcmp(&old_attr, attr, sizeof(*attr)))
return -EINVAL;
}
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;
}