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authorMarco Elver <elver@google.com>2020-02-07 19:59:10 +0100
committerIngo Molnar <mingo@kernel.org>2020-03-21 09:43:35 +0100
commit80d4c4775216602ccdc9e761ce251c8451d0c6ca (patch)
treed3dac351e3d2dfb461f26bb96c304e8895c5ebbf /kernel/kcsan
parentkcsan: Add test to generate conflicts via debugfs (diff)
downloadlinux-80d4c4775216602ccdc9e761ce251c8451d0c6ca.tar.xz
linux-80d4c4775216602ccdc9e761ce251c8451d0c6ca.zip
kcsan: Expose core configuration parameters as module params
This adds early_boot, udelay_{task,interrupt}, and skip_watch as module params. The latter parameters are useful to modify at runtime to tune KCSAN's performance on new systems. This will also permit auto-tuning these parameters to maximize overall system performance and KCSAN's race detection ability. None of the parameters are used in the fast-path and referring to them via static variables instead of CONFIG constants will not affect performance. Signed-off-by: Marco Elver <elver@google.com> Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: Qian Cai <cai@lca.pw>
Diffstat (limited to 'kernel/kcsan')
-rw-r--r--kernel/kcsan/core.c24
1 files changed, 19 insertions, 5 deletions
diff --git a/kernel/kcsan/core.c b/kernel/kcsan/core.c
index 87ef01e40199..498b1eb3c1cd 100644
--- a/kernel/kcsan/core.c
+++ b/kernel/kcsan/core.c
@@ -6,6 +6,7 @@
#include <linux/export.h>
#include <linux/init.h>
#include <linux/kernel.h>
+#include <linux/moduleparam.h>
#include <linux/percpu.h>
#include <linux/preempt.h>
#include <linux/random.h>
@@ -16,6 +17,20 @@
#include "encoding.h"
#include "kcsan.h"
+static bool kcsan_early_enable = IS_ENABLED(CONFIG_KCSAN_EARLY_ENABLE);
+static unsigned int kcsan_udelay_task = CONFIG_KCSAN_UDELAY_TASK;
+static unsigned int kcsan_udelay_interrupt = CONFIG_KCSAN_UDELAY_INTERRUPT;
+static long kcsan_skip_watch = CONFIG_KCSAN_SKIP_WATCH;
+
+#ifdef MODULE_PARAM_PREFIX
+#undef MODULE_PARAM_PREFIX
+#endif
+#define MODULE_PARAM_PREFIX "kcsan."
+module_param_named(early_enable, kcsan_early_enable, bool, 0);
+module_param_named(udelay_task, kcsan_udelay_task, uint, 0644);
+module_param_named(udelay_interrupt, kcsan_udelay_interrupt, uint, 0644);
+module_param_named(skip_watch, kcsan_skip_watch, long, 0644);
+
bool kcsan_enabled;
/* Per-CPU kcsan_ctx for interrupts */
@@ -239,9 +254,9 @@ should_watch(const volatile void *ptr, size_t size, int type)
static inline void reset_kcsan_skip(void)
{
- long skip_count = CONFIG_KCSAN_SKIP_WATCH -
+ long skip_count = kcsan_skip_watch -
(IS_ENABLED(CONFIG_KCSAN_SKIP_WATCH_RANDOMIZE) ?
- prandom_u32_max(CONFIG_KCSAN_SKIP_WATCH) :
+ prandom_u32_max(kcsan_skip_watch) :
0);
this_cpu_write(kcsan_skip, skip_count);
}
@@ -253,8 +268,7 @@ static __always_inline bool kcsan_is_enabled(void)
static inline unsigned int get_delay(void)
{
- unsigned int delay = in_task() ? CONFIG_KCSAN_UDELAY_TASK :
- CONFIG_KCSAN_UDELAY_INTERRUPT;
+ unsigned int delay = in_task() ? kcsan_udelay_task : kcsan_udelay_interrupt;
return delay - (IS_ENABLED(CONFIG_KCSAN_DELAY_RANDOMIZE) ?
prandom_u32_max(delay) :
0);
@@ -527,7 +541,7 @@ void __init kcsan_init(void)
* We are in the init task, and no other tasks should be running;
* WRITE_ONCE without memory barrier is sufficient.
*/
- if (IS_ENABLED(CONFIG_KCSAN_EARLY_ENABLE))
+ if (kcsan_early_enable)
WRITE_ONCE(kcsan_enabled, true);
}