The following commit has been merged into the core/mm branch of tip: Commit-ID: 6e799cb69a70eedbb41561b750f7180c12cff280 Gitweb: https://git.kernel.org/tip/6e799cb69a70eedbb41561b750f7180c12cff280 Author: Thomas Gleixner <tglx@xxxxxxxxxxxxx> AuthorDate: Wed, 18 Nov 2020 20:48:39 +01:00 Committer: Thomas Gleixner <tglx@xxxxxxxxxxxxx> CommitterDate: Tue, 24 Nov 2020 14:42:08 +01:00 mm/highmem: Provide and use CONFIG_DEBUG_KMAP_LOCAL 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@xxxxxxxxxxxxx> Acked-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx> Link: https://lore.kernel.org/r/20201118204006.869487226@xxxxxxxxxxxxx --- include/asm-generic/kmap_size.h | 2 +- lib/Kconfig.debug | 8 ++++++++ mm/highmem.c | 4 ++-- 3 files changed, 11 insertions(+), 3 deletions(-) diff --git a/include/asm-generic/kmap_size.h b/include/asm-generic/kmap_size.h index 9d6c778..6e36b24 100644 --- a/include/asm-generic/kmap_size.h +++ b/include/asm-generic/kmap_size.h @@ -3,7 +3,7 @@ #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 diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index c789b39..f24fa15 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -849,9 +849,17 @@ config DEBUG_PER_CPU_MAPS 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. diff --git a/mm/highmem.c b/mm/highmem.c index 78c481a..fab128d 100644 --- a/mm/highmem.c +++ b/mm/highmem.c @@ -368,10 +368,10 @@ EXPORT_SYMBOL(kunmap_high); 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
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