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KASAN maps shadow for the entire CPU-entry-area: [CPU_ENTRY_AREA_BASE, CPU_ENTRY_AREA_BASE + CPU_ENTRY_AREA_MAP_SIZE] This will explode once the per-cpu entry areas are randomized since it will increase CPU_ENTRY_AREA_MAP_SIZE to 512 GB and KASAN fails to allocate shadow for such big area. Fix this by allocating KASAN shadow only for really used cpu entry area addresses mapped by cea_map_percpu_pages() Thanks to the 0day folks for finding and reporting this to be an issue. [ dhansen: tweak changelog since this will get committed before peterz's actual cpu-entry-area randomization ] Signed-off-by: Andrey Ryabinin <ryabinin.a.a@gmail.com> Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Tested-by: Yujie Liu <yujie.liu@intel.com> Cc: kernel test robot <yujie.liu@intel.com> Link: https://lore.kernel.org/r/202210241508.2e203c3d-yujie.liu@intel.com
42 lines
1.3 KiB
C
42 lines
1.3 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _ASM_X86_KASAN_H
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#define _ASM_X86_KASAN_H
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#include <linux/const.h>
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#define KASAN_SHADOW_OFFSET _AC(CONFIG_KASAN_SHADOW_OFFSET, UL)
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#define KASAN_SHADOW_SCALE_SHIFT 3
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/*
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* Compiler uses shadow offset assuming that addresses start
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* from 0. Kernel addresses don't start from 0, so shadow
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* for kernel really starts from compiler's shadow offset +
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* 'kernel address space start' >> KASAN_SHADOW_SCALE_SHIFT
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*/
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#define KASAN_SHADOW_START (KASAN_SHADOW_OFFSET + \
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((-1UL << __VIRTUAL_MASK_SHIFT) >> \
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KASAN_SHADOW_SCALE_SHIFT))
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/*
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* 47 bits for kernel address -> (47 - KASAN_SHADOW_SCALE_SHIFT) bits for shadow
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* 56 bits for kernel address -> (56 - KASAN_SHADOW_SCALE_SHIFT) bits for shadow
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*/
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#define KASAN_SHADOW_END (KASAN_SHADOW_START + \
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(1ULL << (__VIRTUAL_MASK_SHIFT - \
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KASAN_SHADOW_SCALE_SHIFT)))
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#ifndef __ASSEMBLY__
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#ifdef CONFIG_KASAN
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void __init kasan_early_init(void);
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void __init kasan_init(void);
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void __init kasan_populate_shadow_for_vaddr(void *va, size_t size, int nid);
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#else
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static inline void kasan_early_init(void) { }
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static inline void kasan_init(void) { }
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static inline void kasan_populate_shadow_for_vaddr(void *va, size_t size,
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int nid) { }
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#endif
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#endif
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#endif
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