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5dff03813f
By default 3-level paging is used when the kernel is compiled with kasan support. Add 4-level paging option to support systems with more then 3TB of physical memory and to cover 4-level paging specific code with kasan as well. Reviewed-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
78 lines
2.5 KiB
Plaintext
78 lines
2.5 KiB
Plaintext
config HAVE_ARCH_KASAN
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bool
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if HAVE_ARCH_KASAN
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config KASAN
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bool "KASan: runtime memory debugger"
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depends on (SLUB && SYSFS) || (SLAB && !DEBUG_SLAB)
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select SLUB_DEBUG if SLUB
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select CONSTRUCTORS
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select STACKDEPOT
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help
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Enables kernel address sanitizer - runtime memory debugger,
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designed to find out-of-bounds accesses and use-after-free bugs.
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This is strictly a debugging feature and it requires a gcc version
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of 4.9.2 or later. Detection of out of bounds accesses to stack or
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global variables requires gcc 5.0 or later.
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This feature consumes about 1/8 of available memory and brings about
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~x3 performance slowdown.
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For better error detection enable CONFIG_STACKTRACE.
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Currently CONFIG_KASAN doesn't work with CONFIG_DEBUG_SLAB
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(the resulting kernel does not boot).
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config KASAN_EXTRA
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bool "KAsan: extra checks"
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depends on KASAN && DEBUG_KERNEL && !COMPILE_TEST
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help
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This enables further checks in the kernel address sanitizer, for now
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it only includes the address-use-after-scope check that can lead
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to excessive kernel stack usage, frame size warnings and longer
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compile time.
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81715 has more
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choice
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prompt "Instrumentation type"
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depends on KASAN
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default KASAN_OUTLINE
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config KASAN_OUTLINE
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bool "Outline instrumentation"
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help
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Before every memory access compiler insert function call
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__asan_load*/__asan_store*. These functions performs check
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of shadow memory. This is slower than inline instrumentation,
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however it doesn't bloat size of kernel's .text section so
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much as inline does.
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config KASAN_INLINE
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bool "Inline instrumentation"
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help
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Compiler directly inserts code checking shadow memory before
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memory accesses. This is faster than outline (in some workloads
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it gives about x2 boost over outline instrumentation), but
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make kernel's .text size much bigger.
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This requires a gcc version of 5.0 or later.
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endchoice
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config KASAN_S390_4_LEVEL_PAGING
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bool "KASan: use 4-level paging"
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depends on KASAN && S390
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help
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Compiling the kernel with KASan disables automatic 3-level vs
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4-level paging selection. 3-level paging is used by default (up
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to 3TB of RAM with KASan enabled). This options allows to force
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4-level paging instead.
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config TEST_KASAN
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tristate "Module for testing kasan for bug detection"
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depends on m && KASAN
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help
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This is a test module doing various nasty things like
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out of bounds accesses, use after free. It is useful for testing
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kernel debugging features like kernel address sanitizer.
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endif
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