CONFIG_KMAP_LOCAL can be enabled by x86/32bit even if CONFIG_HIGHMEM is not
enabled for temporary MMIO space mappings.
Provide it as a seperate config option which depends on CONFIG_KMAP_LOCAL
and let CONFIG_DEBUG_HIGHMEM select it.
This won't increase the debug coverage of this significantly but it paves
the way to do so.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20201118204006.869487226@linutronix.de
#define _ASM_GENERIC_KMAP_SIZE_H
/* For debug this provides guard pages between the maps */
-#ifdef CONFIG_DEBUG_HIGHMEM
+#ifdef CONFIG_DEBUG_KMAP_LOCAL
# define KM_MAX_IDX 33
#else
# define KM_MAX_IDX 16
Say N if unsure.
+config DEBUG_KMAP_LOCAL
+ bool "Debug kmap_local temporary mappings"
+ depends on DEBUG_KERNEL && KMAP_LOCAL
+ help
+ This option enables additional error checking for the kmap_local
+ infrastructure. Disable for production use.
+
config DEBUG_HIGHMEM
bool "Highmem debugging"
depends on DEBUG_KERNEL && HIGHMEM
+ select DEBUG_KMAP_LOCAL
help
This option enables additional error checking for high memory
systems. Disable for production systems.
static DEFINE_PER_CPU(int, __kmap_local_idx);
/*
- * With DEBUG_HIGHMEM the stack depth is doubled and every second
+ * With DEBUG_KMAP_LOCAL the stack depth is doubled and every second
* slot is unused which acts as a guard page
*/
-#ifdef CONFIG_DEBUG_HIGHMEM
+#ifdef CONFIG_DEBUG_KMAP_LOCAL
# define KM_INCR 2
#else
# define KM_INCR 1