Add a new Kconfig symbol to make CONFIG_DEBUG_ATOMIC more useful on
those architectures which do not align dynamic allocations to 8-byte
boundaries. Without this, CONFIG_DEBUG_ATOMIC produces excessive
WARN splats.
Signed-off-by: Finn Thain <fthain@linux-m68k.org>
---
Changed since v6:
- Rebased.
Changed since v5:
- Rebased.
Changed since v3:
- Dropped #include <linux/cache.h> to avoid a build failure on arm64.
- Rewrote Kconfig help text to better describe preferred alignment.
- Refactored to avoid line-wrapping and duplication.
---
include/linux/instrumented.h | 8 +++++++-
lib/Kconfig.debug | 8 ++++++++
2 files changed, 15 insertions(+), 1 deletion(-)
diff --git a/include/linux/instrumented.h b/include/linux/instrumented.h
index e34b6a557e0a..a1b4cf81adc2 100644
--- a/include/linux/instrumented.h
+++ b/include/linux/instrumented.h
@@ -59,7 +59,13 @@ static __always_inline void instrument_read_write(const volatile void *v, size_t
static __always_inline void instrument_atomic_check_alignment(const volatile void *v, size_t size)
{
#ifndef __DISABLE_EXPORTS
- WARN_ON_ONCE(IS_ENABLED(CONFIG_DEBUG_ATOMIC) && ((unsigned long)v & (size - 1)));
+ if (IS_ENABLED(CONFIG_DEBUG_ATOMIC)) {
+ unsigned int mask = size - 1;
+
+ if (IS_ENABLED(CONFIG_DEBUG_ATOMIC_LARGEST_ALIGN))
+ mask &= sizeof(struct { long x; } __aligned_largest) - 1;
+ WARN_ON_ONCE((unsigned long)v & mask);
+ }
#endif
}
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 4b4d1445ef9c..977a2c9163a2 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -1369,6 +1369,14 @@ config DEBUG_ATOMIC
This option has potentially significant overhead.
+config DEBUG_ATOMIC_LARGEST_ALIGN
+ bool "Check alignment only up to __aligned_largest"
+ depends on DEBUG_ATOMIC
+ help
+ If you say Y here then the check for natural alignment of
+ atomic accesses will be constrained to the compiler's largest
+ alignment for scalar types.
+
menu "Lock Debugging (spinlocks, mutexes, etc...)"
config LOCK_DEBUGGING_SUPPORT
--
2.49.1