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authorAndrey Konovalov <andreyknvl@google.com>2020-06-04 16:46:01 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2020-06-04 19:06:20 -0700
commit5fe7042dc0a2e80b4633df20dcd06b93e76e3c31 (patch)
treed9e0fc8bc2a6fec1977dd46654c5db046d2bfe9a /kernel/kcov.c
parenteeb91f9a2e3e9766ae9fd1117bd19d87538f21bf (diff)
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kcov: use t->kcov_mode as enabled indicator
Currently kcov_remote_start() and kcov_remote_stop() check t->kcov to find out whether the coverage is already being collected by the current task. Use t->kcov_mode for that instead. This doesn't change the overall behavior in any way, but serves as a preparation for the following softirq coverage collection support patch. Signed-off-by: Andrey Konovalov <andreyknvl@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Dmitry Vyukov <dvyukov@google.com> Cc: Alan Stern <stern@rowland.harvard.edu> Cc: Alexander Potapenko <glider@google.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Marco Elver <elver@google.com> Cc: Andrey Konovalov <andreyknvl@gmail.com> Link: http://lkml.kernel.org/r/f70377945d1d8e6e4916cbce871a12303d6186b4.1585233617.git.andreyknvl@google.com Link: http://lkml.kernel.org/r/ee1a1dec43059da5d7664c85c1addc89c4cd58de.1584655448.git.andreyknvl@google.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel/kcov.c')
-rw-r--r--kernel/kcov.c32
1 files changed, 23 insertions, 9 deletions
diff --git a/kernel/kcov.c b/kernel/kcov.c
index 7cd05bd1fada..93b28ad2da28 100644
--- a/kernel/kcov.c
+++ b/kernel/kcov.c
@@ -746,26 +746,33 @@ static const struct file_operations kcov_fops = {
* In turns kcov_remote_stop() clears those pointers from task_struct to stop
* collecting coverage and copies all collected coverage into the kcov area.
*/
+
+static inline bool kcov_mode_enabled(unsigned int mode)
+{
+ return (mode & ~KCOV_IN_CTXSW) != KCOV_MODE_DISABLED;
+}
+
void kcov_remote_start(u64 handle)
{
+ struct task_struct *t = current;
struct kcov_remote *remote;
struct kcov *kcov;
+ unsigned int mode;
void *area;
- struct task_struct *t;
unsigned int size;
- enum kcov_mode mode;
int sequence;
if (WARN_ON(!kcov_check_handle(handle, true, true, true)))
return;
if (WARN_ON(!in_task()))
return;
- t = current;
+
/*
* Check that kcov_remote_start is not called twice
* nor called by user tasks (with enabled kcov).
*/
- if (WARN_ON(t->kcov))
+ mode = READ_ONCE(t->kcov_mode);
+ if (WARN_ON(kcov_mode_enabled(mode)))
return;
kcov_debug("handle = %llx\n", handle);
@@ -863,13 +870,20 @@ static void kcov_move_area(enum kcov_mode mode, void *dst_area,
void kcov_remote_stop(void)
{
struct task_struct *t = current;
- struct kcov *kcov = t->kcov;
- void *area = t->kcov_area;
- unsigned int size = t->kcov_size;
- int sequence = t->kcov_sequence;
+ struct kcov *kcov;
+ unsigned int mode;
+ void *area;
+ unsigned int size;
+ int sequence;
- if (!kcov)
+ mode = READ_ONCE(t->kcov_mode);
+ barrier();
+ if (!kcov_mode_enabled(mode))
return;
+ kcov = t->kcov;
+ area = t->kcov_area;
+ size = t->kcov_size;
+ sequence = t->kcov_sequence;
kcov_stop(t);