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linux/arch/arm64/include/asm/kasan.h

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arm64: add KASAN support This patch adds arch specific code for kernel address sanitizer (see Documentation/kasan.txt). 1/8 of kernel addresses reserved for shadow memory. There was no big enough hole for this, so virtual addresses for shadow were stolen from vmalloc area. At early boot stage the whole shadow region populated with just one physical page (kasan_zero_page). Later, this page reused as readonly zero shadow for some memory that KASan currently don't track (vmalloc). After mapping the physical memory, pages for shadow memory are allocated and mapped. Functions like memset/memmove/memcpy do a lot of memory accesses. If bad pointer passed to one of these function it is important to catch this. Compiler's instrumentation cannot do this since these functions are written in assembly. KASan replaces memory functions with manually instrumented variants. Original functions declared as weak symbols so strong definitions in mm/kasan/kasan.c could replace them. Original functions have aliases with '__' prefix in name, so we could call non-instrumented variant if needed. Some files built without kasan instrumentation (e.g. mm/slub.c). Original mem* function replaced (via #define) with prefixed variants to disable memory access checks for such files. Signed-off-by: Andrey Ryabinin <ryabinin.a.a@gmail.com> Tested-by: Linus Walleij <linus.walleij@linaro.org> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2015-10-12 15:52:58 +00:00
#ifndef __ASM_KASAN_H
#define __ASM_KASAN_H
#ifndef __ASSEMBLY__
#ifdef CONFIG_KASAN
arm64: kasan: fix issues reported by sparse Sparse reports some new issues introduced by the kasan patches: arch/arm64/mm/kasan_init.c:91:13: warning: no previous prototype for 'kasan_early_init' [-Wmissing-prototypes] void __init kasan_early_init(void) ^ arch/arm64/mm/kasan_init.c:91:13: warning: symbol 'kasan_early_init' was not declared. Should it be static? [sparse] This patch resolves the problem by adding a prototype for kasan_early_init and marking the function as asmlinkage, since it's only called from head.S. Signed-off-by: Will Deacon <will.deacon@arm.com> Acked-by: Andrey Ryabinin <ryabinin.a.a@gmail.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2015-10-13 13:01:06 +00:00
#include <linux/linkage.h>
arm64: add KASAN support This patch adds arch specific code for kernel address sanitizer (see Documentation/kasan.txt). 1/8 of kernel addresses reserved for shadow memory. There was no big enough hole for this, so virtual addresses for shadow were stolen from vmalloc area. At early boot stage the whole shadow region populated with just one physical page (kasan_zero_page). Later, this page reused as readonly zero shadow for some memory that KASan currently don't track (vmalloc). After mapping the physical memory, pages for shadow memory are allocated and mapped. Functions like memset/memmove/memcpy do a lot of memory accesses. If bad pointer passed to one of these function it is important to catch this. Compiler's instrumentation cannot do this since these functions are written in assembly. KASan replaces memory functions with manually instrumented variants. Original functions declared as weak symbols so strong definitions in mm/kasan/kasan.c could replace them. Original functions have aliases with '__' prefix in name, so we could call non-instrumented variant if needed. Some files built without kasan instrumentation (e.g. mm/slub.c). Original mem* function replaced (via #define) with prefixed variants to disable memory access checks for such files. Signed-off-by: Andrey Ryabinin <ryabinin.a.a@gmail.com> Tested-by: Linus Walleij <linus.walleij@linaro.org> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2015-10-12 15:52:58 +00:00
#include <asm/memory.h>
arm64: mm: create new fine-grained mappings at boot At boot we may change the granularity of the tables mapping the kernel (by splitting or making sections). This may happen when we create the linear mapping (in __map_memblock), or at any point we try to apply fine-grained permissions to the kernel (e.g. fixup_executable, mark_rodata_ro, fixup_init). Changing the active page tables in this manner may result in multiple entries for the same address being allocated into TLBs, risking problems such as TLB conflict aborts or issues derived from the amalgamation of TLB entries. Generally, a break-before-make (BBM) approach is necessary to avoid conflicts, but we cannot do this for the kernel tables as it risks unmapping text or data being used to do so. Instead, we can create a new set of tables from scratch in the safety of the existing mappings, and subsequently migrate over to these using the new cpu_replace_ttbr1 helper, which avoids the two sets of tables being active simultaneously. To avoid issues when we later modify permissions of the page tables (e.g. in fixup_init), we must create the page tables at a granularity such that later modification does not result in splitting of tables. This patch applies this strategy, creating a new set of fine-grained page tables from scratch, and safely migrating to them. The existing fixmap and kasan shadow page tables are reused in the new fine-grained tables. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com> Tested-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Tested-by: Jeremy Linton <jeremy.linton@arm.com> Cc: Laura Abbott <labbott@fedoraproject.org> Cc: Will Deacon <will.deacon@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2016-01-25 11:45:12 +00:00
#include <asm/pgtable-types.h>
arm64: add KASAN support This patch adds arch specific code for kernel address sanitizer (see Documentation/kasan.txt). 1/8 of kernel addresses reserved for shadow memory. There was no big enough hole for this, so virtual addresses for shadow were stolen from vmalloc area. At early boot stage the whole shadow region populated with just one physical page (kasan_zero_page). Later, this page reused as readonly zero shadow for some memory that KASan currently don't track (vmalloc). After mapping the physical memory, pages for shadow memory are allocated and mapped. Functions like memset/memmove/memcpy do a lot of memory accesses. If bad pointer passed to one of these function it is important to catch this. Compiler's instrumentation cannot do this since these functions are written in assembly. KASan replaces memory functions with manually instrumented variants. Original functions declared as weak symbols so strong definitions in mm/kasan/kasan.c could replace them. Original functions have aliases with '__' prefix in name, so we could call non-instrumented variant if needed. Some files built without kasan instrumentation (e.g. mm/slub.c). Original mem* function replaced (via #define) with prefixed variants to disable memory access checks for such files. Signed-off-by: Andrey Ryabinin <ryabinin.a.a@gmail.com> Tested-by: Linus Walleij <linus.walleij@linaro.org> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2015-10-12 15:52:58 +00:00
/*
* KASAN_SHADOW_START: beginning of the kernel virtual addresses.
* KASAN_SHADOW_END: KASAN_SHADOW_START + 1/8 of kernel virtual addresses.
*/
#define KASAN_SHADOW_START (VA_START)
arm64: move kernel image to base of vmalloc area This moves the module area to right before the vmalloc area, and moves the kernel image to the base of the vmalloc area. This is an intermediate step towards implementing KASLR, which allows the kernel image to be located anywhere in the vmalloc area. Since other subsystems such as hibernate may still need to refer to the kernel text or data segments via their linears addresses, both are mapped in the linear region as well. The linear alias of the text region is mapped read-only/non-executable to prevent inadvertent modification or execution. Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2016-02-16 12:52:40 +00:00
#define KASAN_SHADOW_END (KASAN_SHADOW_START + KASAN_SHADOW_SIZE)
arm64: add KASAN support This patch adds arch specific code for kernel address sanitizer (see Documentation/kasan.txt). 1/8 of kernel addresses reserved for shadow memory. There was no big enough hole for this, so virtual addresses for shadow were stolen from vmalloc area. At early boot stage the whole shadow region populated with just one physical page (kasan_zero_page). Later, this page reused as readonly zero shadow for some memory that KASan currently don't track (vmalloc). After mapping the physical memory, pages for shadow memory are allocated and mapped. Functions like memset/memmove/memcpy do a lot of memory accesses. If bad pointer passed to one of these function it is important to catch this. Compiler's instrumentation cannot do this since these functions are written in assembly. KASan replaces memory functions with manually instrumented variants. Original functions declared as weak symbols so strong definitions in mm/kasan/kasan.c could replace them. Original functions have aliases with '__' prefix in name, so we could call non-instrumented variant if needed. Some files built without kasan instrumentation (e.g. mm/slub.c). Original mem* function replaced (via #define) with prefixed variants to disable memory access checks for such files. Signed-off-by: Andrey Ryabinin <ryabinin.a.a@gmail.com> Tested-by: Linus Walleij <linus.walleij@linaro.org> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2015-10-12 15:52:58 +00:00
/*
* This value is used to map an address to the corresponding shadow
* address by the following formula:
* shadow_addr = (address >> 3) + KASAN_SHADOW_OFFSET;
*
* (1 << 61) shadow addresses - [KASAN_SHADOW_OFFSET,KASAN_SHADOW_END]
* cover all 64-bits of virtual addresses. So KASAN_SHADOW_OFFSET
* should satisfy the following equation:
* KASAN_SHADOW_OFFSET = KASAN_SHADOW_END - (1ULL << 61)
*/
#define KASAN_SHADOW_OFFSET (KASAN_SHADOW_END - (1ULL << (64 - 3)))
void kasan_init(void);
arm64: mm: create new fine-grained mappings at boot At boot we may change the granularity of the tables mapping the kernel (by splitting or making sections). This may happen when we create the linear mapping (in __map_memblock), or at any point we try to apply fine-grained permissions to the kernel (e.g. fixup_executable, mark_rodata_ro, fixup_init). Changing the active page tables in this manner may result in multiple entries for the same address being allocated into TLBs, risking problems such as TLB conflict aborts or issues derived from the amalgamation of TLB entries. Generally, a break-before-make (BBM) approach is necessary to avoid conflicts, but we cannot do this for the kernel tables as it risks unmapping text or data being used to do so. Instead, we can create a new set of tables from scratch in the safety of the existing mappings, and subsequently migrate over to these using the new cpu_replace_ttbr1 helper, which avoids the two sets of tables being active simultaneously. To avoid issues when we later modify permissions of the page tables (e.g. in fixup_init), we must create the page tables at a granularity such that later modification does not result in splitting of tables. This patch applies this strategy, creating a new set of fine-grained page tables from scratch, and safely migrating to them. The existing fixmap and kasan shadow page tables are reused in the new fine-grained tables. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com> Tested-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Tested-by: Jeremy Linton <jeremy.linton@arm.com> Cc: Laura Abbott <labbott@fedoraproject.org> Cc: Will Deacon <will.deacon@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2016-01-25 11:45:12 +00:00
void kasan_copy_shadow(pgd_t *pgdir);
arm64: kasan: fix issues reported by sparse Sparse reports some new issues introduced by the kasan patches: arch/arm64/mm/kasan_init.c:91:13: warning: no previous prototype for 'kasan_early_init' [-Wmissing-prototypes] void __init kasan_early_init(void) ^ arch/arm64/mm/kasan_init.c:91:13: warning: symbol 'kasan_early_init' was not declared. Should it be static? [sparse] This patch resolves the problem by adding a prototype for kasan_early_init and marking the function as asmlinkage, since it's only called from head.S. Signed-off-by: Will Deacon <will.deacon@arm.com> Acked-by: Andrey Ryabinin <ryabinin.a.a@gmail.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2015-10-13 13:01:06 +00:00
asmlinkage void kasan_early_init(void);
arm64: add KASAN support This patch adds arch specific code for kernel address sanitizer (see Documentation/kasan.txt). 1/8 of kernel addresses reserved for shadow memory. There was no big enough hole for this, so virtual addresses for shadow were stolen from vmalloc area. At early boot stage the whole shadow region populated with just one physical page (kasan_zero_page). Later, this page reused as readonly zero shadow for some memory that KASan currently don't track (vmalloc). After mapping the physical memory, pages for shadow memory are allocated and mapped. Functions like memset/memmove/memcpy do a lot of memory accesses. If bad pointer passed to one of these function it is important to catch this. Compiler's instrumentation cannot do this since these functions are written in assembly. KASan replaces memory functions with manually instrumented variants. Original functions declared as weak symbols so strong definitions in mm/kasan/kasan.c could replace them. Original functions have aliases with '__' prefix in name, so we could call non-instrumented variant if needed. Some files built without kasan instrumentation (e.g. mm/slub.c). Original mem* function replaced (via #define) with prefixed variants to disable memory access checks for such files. Signed-off-by: Andrey Ryabinin <ryabinin.a.a@gmail.com> Tested-by: Linus Walleij <linus.walleij@linaro.org> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2015-10-12 15:52:58 +00:00
#else
static inline void kasan_init(void) { }
arm64: mm: create new fine-grained mappings at boot At boot we may change the granularity of the tables mapping the kernel (by splitting or making sections). This may happen when we create the linear mapping (in __map_memblock), or at any point we try to apply fine-grained permissions to the kernel (e.g. fixup_executable, mark_rodata_ro, fixup_init). Changing the active page tables in this manner may result in multiple entries for the same address being allocated into TLBs, risking problems such as TLB conflict aborts or issues derived from the amalgamation of TLB entries. Generally, a break-before-make (BBM) approach is necessary to avoid conflicts, but we cannot do this for the kernel tables as it risks unmapping text or data being used to do so. Instead, we can create a new set of tables from scratch in the safety of the existing mappings, and subsequently migrate over to these using the new cpu_replace_ttbr1 helper, which avoids the two sets of tables being active simultaneously. To avoid issues when we later modify permissions of the page tables (e.g. in fixup_init), we must create the page tables at a granularity such that later modification does not result in splitting of tables. This patch applies this strategy, creating a new set of fine-grained page tables from scratch, and safely migrating to them. The existing fixmap and kasan shadow page tables are reused in the new fine-grained tables. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com> Tested-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Tested-by: Jeremy Linton <jeremy.linton@arm.com> Cc: Laura Abbott <labbott@fedoraproject.org> Cc: Will Deacon <will.deacon@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2016-01-25 11:45:12 +00:00
static inline void kasan_copy_shadow(pgd_t *pgdir) { }
arm64: add KASAN support This patch adds arch specific code for kernel address sanitizer (see Documentation/kasan.txt). 1/8 of kernel addresses reserved for shadow memory. There was no big enough hole for this, so virtual addresses for shadow were stolen from vmalloc area. At early boot stage the whole shadow region populated with just one physical page (kasan_zero_page). Later, this page reused as readonly zero shadow for some memory that KASan currently don't track (vmalloc). After mapping the physical memory, pages for shadow memory are allocated and mapped. Functions like memset/memmove/memcpy do a lot of memory accesses. If bad pointer passed to one of these function it is important to catch this. Compiler's instrumentation cannot do this since these functions are written in assembly. KASan replaces memory functions with manually instrumented variants. Original functions declared as weak symbols so strong definitions in mm/kasan/kasan.c could replace them. Original functions have aliases with '__' prefix in name, so we could call non-instrumented variant if needed. Some files built without kasan instrumentation (e.g. mm/slub.c). Original mem* function replaced (via #define) with prefixed variants to disable memory access checks for such files. Signed-off-by: Andrey Ryabinin <ryabinin.a.a@gmail.com> Tested-by: Linus Walleij <linus.walleij@linaro.org> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2015-10-12 15:52:58 +00:00
#endif
#endif
#endif
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