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| author | Thomas Gleixner <tglx@linutronix.de> | 2020-11-18 20:48:41 +0100 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2020-11-24 14:42:09 +0100 |
| commit | 14df32670291588036a498051a54cd8462d7f611 (patch) | |
| tree | b3285fcdb143e581c262a49f4e021c38ac362ceb /arch/x86/Kconfig | |
| parent | mm/highmem: Provide CONFIG_DEBUG_KMAP_LOCAL_FORCE_MAP (diff) | |
| download | linux-14df32670291588036a498051a54cd8462d7f611.tar.xz linux-14df32670291588036a498051a54cd8462d7f611.zip | |
x86: Support kmap_local() forced debugging
kmap_local() and related interfaces are NOOPs on 64bit and only create
temporary fixmaps for highmem pages on 32bit. That means the test coverage
for this code is pretty small.
CONFIG_KMAP_LOCAL can be enabled independent from CONFIG_HIGHMEM, which
allows to provide support for enforced kmap_local() debugging even on
64bit.
For 32bit the support is unconditional, for 64bit it's only supported when
CONFIG_NR_CPUS <= 4096 as supporting it for 8192 CPUs would require to set
up yet another fixmap PGT.
If CONFIG_KMAP_LOCAL_FORCE_DEBUG is enabled then kmap_local()/kmap_atomic()
will use the temporary fixmap mapping path.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20201118204007.169209557@linutronix.de
Diffstat (limited to 'arch/x86/Kconfig')
| -rw-r--r-- | arch/x86/Kconfig | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 33c273cb3023..b5137cc5b7b4 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -93,6 +93,7 @@ config X86 select ARCH_SUPPORTS_ACPI select ARCH_SUPPORTS_ATOMIC_RMW select ARCH_SUPPORTS_NUMA_BALANCING if X86_64 + select ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP if NR_CPUS <= 4096 select ARCH_USE_BUILTIN_BSWAP select ARCH_USE_QUEUED_RWLOCKS select ARCH_USE_QUEUED_SPINLOCKS |