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1e338f4d99
Patch series "kasan: unify kasan_enabled() and remove arch-specific
implementations", v6.
This patch series addresses the fragmentation in KASAN initialization
across architectures by introducing a unified approach that eliminates
duplicate static keys and arch-specific kasan_arch_is_ready()
implementations.
The core issue is that different architectures have inconsistent approaches
to KASAN readiness tracking:
- PowerPC, LoongArch, and UML arch, each implement own kasan_arch_is_ready()
- Only HW_TAGS mode had a unified static key (kasan_flag_enabled)
- Generic and SW_TAGS modes relied on arch-specific solutions
or always-on behavior
This patch (of 2):
Introduce CONFIG_ARCH_DEFER_KASAN to identify architectures [1] that need
to defer KASAN initialization until shadow memory is properly set up, and
unify the static key infrastructure across all KASAN modes.
[1] PowerPC, UML, LoongArch selects ARCH_DEFER_KASAN.
The core issue is that different architectures haveinconsistent approaches
to KASAN readiness tracking:
- PowerPC, LoongArch, and UML arch, each implement own
kasan_arch_is_ready()
- Only HW_TAGS mode had a unified static key (kasan_flag_enabled)
- Generic and SW_TAGS modes relied on arch-specific solutions or always-on
behavior
This patch addresses the fragmentation in KASAN initialization across
architectures by introducing a unified approach that eliminates duplicate
static keys and arch-specific kasan_arch_is_ready() implementations.
Let's replace kasan_arch_is_ready() with existing kasan_enabled() check,
which examines the static key being enabled if arch selects
ARCH_DEFER_KASAN or has HW_TAGS mode support. For other arch,
kasan_enabled() checks the enablement during compile time.
Now KASAN users can use a single kasan_enabled() check everywhere.
Link: https://lkml.kernel.org/r/20250810125746.1105476-1-snovitoll@gmail.com
Link: https://lkml.kernel.org/r/20250810125746.1105476-2-snovitoll@gmail.com
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=217049
Signed-off-by: Sabyrzhan Tasbolatov <snovitoll@gmail.com>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Reviewed-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com> #powerpc
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Alexandre Ghiti <alex@ghiti.fr>
Cc: Alexandre Ghiti <alexghiti@rivosinc.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: David Gow <davidgow@google.com>
Cc: Dmitriy Vyukov <dvyukov@google.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Huacai Chen <chenhuacai@loongson.cn>
Cc: Marco Elver <elver@google.com>
Cc: Qing Zhang <zhangqing@loongson.cn>
Cc: Sabyrzhan Tasbolatov <snovitoll@gmail.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
50 lines
1.2 KiB
C
50 lines
1.2 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _LINUX_KASAN_ENABLED_H
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#define _LINUX_KASAN_ENABLED_H
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#include <linux/static_key.h>
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#if defined(CONFIG_ARCH_DEFER_KASAN) || defined(CONFIG_KASAN_HW_TAGS)
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/*
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* Global runtime flag for KASAN modes that need runtime control.
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* Used by ARCH_DEFER_KASAN architectures and HW_TAGS mode.
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*/
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DECLARE_STATIC_KEY_FALSE(kasan_flag_enabled);
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/*
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* Runtime control for shadow memory initialization or HW_TAGS mode.
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* Uses static key for architectures that need deferred KASAN or HW_TAGS.
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*/
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static __always_inline bool kasan_enabled(void)
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{
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return static_branch_likely(&kasan_flag_enabled);
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}
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static inline void kasan_enable(void)
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{
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static_branch_enable(&kasan_flag_enabled);
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}
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#else
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/* For architectures that can enable KASAN early, use compile-time check. */
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static __always_inline bool kasan_enabled(void)
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{
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return IS_ENABLED(CONFIG_KASAN);
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}
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static inline void kasan_enable(void) {}
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#endif /* CONFIG_ARCH_DEFER_KASAN || CONFIG_KASAN_HW_TAGS */
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#ifdef CONFIG_KASAN_HW_TAGS
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static inline bool kasan_hw_tags_enabled(void)
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{
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return kasan_enabled();
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}
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#else
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static inline bool kasan_hw_tags_enabled(void)
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{
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return false;
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}
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#endif /* CONFIG_KASAN_HW_TAGS */
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#endif /* LINUX_KASAN_ENABLED_H */
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