kasan: clean up KASAN_SHADOW_SCALE_SHIFT usage
Right now the fact that KASAN uses a single shadow byte for 8 bytes of memory is scattered all over the code. This change defines KASAN_SHADOW_SCALE_SHIFT early in asm include files and makes use of this constant where necessary. [akpm@linux-foundation.org: coding-style fixes] Link: http://lkml.kernel.org/r/34937ca3b90736eaad91b568edf5684091f662e3.1515775666.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov <andreyknvl@google.com> Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Dmitry Vyukov <dvyukov@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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@ -12,7 +12,8 @@
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/*
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* KASAN_SHADOW_START: beginning of the kernel virtual addresses.
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* KASAN_SHADOW_END: KASAN_SHADOW_START + 1/8 of kernel virtual addresses.
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* KASAN_SHADOW_END: KASAN_SHADOW_START + 1/N of kernel virtual addresses,
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* where N = (1 << KASAN_SHADOW_SCALE_SHIFT).
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*/
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#define KASAN_SHADOW_START (VA_START)
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#define KASAN_SHADOW_END (KASAN_SHADOW_START + KASAN_SHADOW_SIZE)
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@ -20,14 +21,16 @@
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/*
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* This value is used to map an address to the corresponding shadow
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* address by the following formula:
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* shadow_addr = (address >> 3) + KASAN_SHADOW_OFFSET;
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* shadow_addr = (address >> KASAN_SHADOW_SCALE_SHIFT) + KASAN_SHADOW_OFFSET
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*
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* (1 << 61) shadow addresses - [KASAN_SHADOW_OFFSET,KASAN_SHADOW_END]
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* cover all 64-bits of virtual addresses. So KASAN_SHADOW_OFFSET
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* should satisfy the following equation:
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* KASAN_SHADOW_OFFSET = KASAN_SHADOW_END - (1ULL << 61)
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* (1 << (64 - KASAN_SHADOW_SCALE_SHIFT)) shadow addresses that lie in range
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* [KASAN_SHADOW_OFFSET, KASAN_SHADOW_END) cover all 64-bits of virtual
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* addresses. So KASAN_SHADOW_OFFSET should satisfy the following equation:
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* KASAN_SHADOW_OFFSET = KASAN_SHADOW_END -
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* (1ULL << (64 - KASAN_SHADOW_SCALE_SHIFT))
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*/
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#define KASAN_SHADOW_OFFSET (KASAN_SHADOW_END - (1ULL << (64 - 3)))
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#define KASAN_SHADOW_OFFSET (KASAN_SHADOW_END - (1ULL << \
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(64 - KASAN_SHADOW_SCALE_SHIFT)))
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void kasan_init(void);
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void kasan_copy_shadow(pgd_t *pgdir);
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@ -85,7 +85,8 @@
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* stack size when KASAN is in use.
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*/
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#ifdef CONFIG_KASAN
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#define KASAN_SHADOW_SIZE (UL(1) << (VA_BITS - 3))
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#define KASAN_SHADOW_SCALE_SHIFT 3
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#define KASAN_SHADOW_SIZE (UL(1) << (VA_BITS - KASAN_SHADOW_SCALE_SHIFT))
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#define KASAN_THREAD_SHIFT 1
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#else
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#define KASAN_SHADOW_SIZE (0)
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@ -135,7 +135,8 @@ static void __init kasan_pgd_populate(unsigned long addr, unsigned long end,
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/* The early shadow maps everything to a single page of zeroes */
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asmlinkage void __init kasan_early_init(void)
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{
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BUILD_BUG_ON(KASAN_SHADOW_OFFSET != KASAN_SHADOW_END - (1UL << 61));
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BUILD_BUG_ON(KASAN_SHADOW_OFFSET !=
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KASAN_SHADOW_END - (1UL << (64 - KASAN_SHADOW_SCALE_SHIFT)));
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BUILD_BUG_ON(!IS_ALIGNED(KASAN_SHADOW_START, PGDIR_SIZE));
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BUILD_BUG_ON(!IS_ALIGNED(KASAN_SHADOW_END, PGDIR_SIZE));
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kasan_pgd_populate(KASAN_SHADOW_START, KASAN_SHADOW_END, NUMA_NO_NODE,
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@ -4,6 +4,7 @@
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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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@ -12,12 +13,15 @@
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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) >> 3))
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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 - 3) bits for shadow
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* 56 bits for kernel address -> (56 - 3) bits for shadow
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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 + (1ULL << (__VIRTUAL_MASK_SHIFT - 3)))
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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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@ -11,8 +11,6 @@ struct task_struct;
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#ifdef CONFIG_KASAN
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#define KASAN_SHADOW_SCALE_SHIFT 3
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#include <asm/kasan.h>
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#include <asm/pgtable.h>
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