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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>
88 lines
3.2 KiB
C
88 lines
3.2 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef __ASM_KASAN_H
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#define __ASM_KASAN_H
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#ifndef __ASSEMBLER__
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#include <linux/linkage.h>
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#include <linux/mmzone.h>
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#include <asm/addrspace.h>
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#include <asm/io.h>
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#include <asm/pgtable.h>
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#define KASAN_SHADOW_SCALE_SHIFT 3
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#define KASAN_SHADOW_OFFSET _AC(CONFIG_KASAN_SHADOW_OFFSET, UL)
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#define XRANGE_SHIFT (48)
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/* Valid address length */
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#define XRANGE_SHADOW_SHIFT min(cpu_vabits, VA_BITS)
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/* Used for taking out the valid address */
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#define XRANGE_SHADOW_MASK GENMASK_ULL(XRANGE_SHADOW_SHIFT - 1, 0)
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/* One segment whole address space size */
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#define XRANGE_SIZE (XRANGE_SHADOW_MASK + 1)
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/* 64-bit segment value. */
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#define XKPRANGE_UC_SEG (0x8000)
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#define XKPRANGE_CC_SEG (0x9000)
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#define XKPRANGE_WC_SEG (0xa000)
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#define XKVRANGE_VC_SEG (0xffff)
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/* Cached */
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#define XKPRANGE_CC_START CACHE_BASE
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#define XKPRANGE_CC_SIZE XRANGE_SIZE
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#define XKPRANGE_CC_KASAN_OFFSET (0)
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#define XKPRANGE_CC_SHADOW_SIZE (XKPRANGE_CC_SIZE >> KASAN_SHADOW_SCALE_SHIFT)
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#define XKPRANGE_CC_SHADOW_END (XKPRANGE_CC_KASAN_OFFSET + XKPRANGE_CC_SHADOW_SIZE)
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/* UnCached */
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#define XKPRANGE_UC_START UNCACHE_BASE
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#define XKPRANGE_UC_SIZE XRANGE_SIZE
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#define XKPRANGE_UC_KASAN_OFFSET XKPRANGE_CC_SHADOW_END
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#define XKPRANGE_UC_SHADOW_SIZE (XKPRANGE_UC_SIZE >> KASAN_SHADOW_SCALE_SHIFT)
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#define XKPRANGE_UC_SHADOW_END (XKPRANGE_UC_KASAN_OFFSET + XKPRANGE_UC_SHADOW_SIZE)
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/* WriteCombine */
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#define XKPRANGE_WC_START WRITECOMBINE_BASE
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#define XKPRANGE_WC_SIZE XRANGE_SIZE
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#define XKPRANGE_WC_KASAN_OFFSET XKPRANGE_UC_SHADOW_END
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#define XKPRANGE_WC_SHADOW_SIZE (XKPRANGE_WC_SIZE >> KASAN_SHADOW_SCALE_SHIFT)
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#define XKPRANGE_WC_SHADOW_END (XKPRANGE_WC_KASAN_OFFSET + XKPRANGE_WC_SHADOW_SIZE)
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/* VMALLOC (Cached or UnCached) */
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#define XKVRANGE_VC_START MODULES_VADDR
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#define XKVRANGE_VC_SIZE round_up(KFENCE_AREA_END - MODULES_VADDR + 1, PGDIR_SIZE)
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#define XKVRANGE_VC_KASAN_OFFSET XKPRANGE_WC_SHADOW_END
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#define XKVRANGE_VC_SHADOW_SIZE (XKVRANGE_VC_SIZE >> KASAN_SHADOW_SCALE_SHIFT)
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#define XKVRANGE_VC_SHADOW_END (XKVRANGE_VC_KASAN_OFFSET + XKVRANGE_VC_SHADOW_SIZE)
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/* KAsan shadow memory start right after vmalloc. */
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#define KASAN_SHADOW_START round_up(KFENCE_AREA_END, PGDIR_SIZE)
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#define KASAN_SHADOW_SIZE (XKVRANGE_VC_SHADOW_END - XKPRANGE_CC_KASAN_OFFSET)
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#define KASAN_SHADOW_END (round_up(KASAN_SHADOW_START + KASAN_SHADOW_SIZE, PGDIR_SIZE) - 1)
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#define XKPRANGE_CC_SHADOW_OFFSET (KASAN_SHADOW_START + XKPRANGE_CC_KASAN_OFFSET)
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#define XKPRANGE_UC_SHADOW_OFFSET (KASAN_SHADOW_START + XKPRANGE_UC_KASAN_OFFSET)
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#define XKPRANGE_WC_SHADOW_OFFSET (KASAN_SHADOW_START + XKPRANGE_WC_KASAN_OFFSET)
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#define XKVRANGE_VC_SHADOW_OFFSET (KASAN_SHADOW_START + XKVRANGE_VC_KASAN_OFFSET)
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extern unsigned char kasan_early_shadow_page[PAGE_SIZE];
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#define kasan_mem_to_shadow kasan_mem_to_shadow
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void *kasan_mem_to_shadow(const void *addr);
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#define kasan_shadow_to_mem kasan_shadow_to_mem
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const void *kasan_shadow_to_mem(const void *shadow_addr);
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#define addr_has_metadata addr_has_metadata
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static __always_inline bool addr_has_metadata(const void *addr)
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{
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return (kasan_mem_to_shadow((void *)addr) != NULL);
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}
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void kasan_init(void);
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asmlinkage void kasan_early_init(void);
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#endif
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#endif
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