summaryrefslogtreecommitdiffstats
path: root/arch/s390/include/asm/kasan.h
AgeCommit message (Collapse)AuthorFilesLines
2018-10-09s390/kasan: add option for 4-level paging supportVasily Gorbik1-0/+5
By default 3-level paging is used when the kernel is compiled with kasan support. Add 4-level paging option to support systems with more then 3TB of physical memory and to cover 4-level paging specific code with kasan as well. Reviewed-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2018-10-09s390/kasan: free early identity mapping structuresVasily Gorbik1-0/+2
Kasan initialization code is changed to populate persistent shadow first, save allocator position into pgalloc_freeable and proceed with early identity mapping creation. This way early identity mapping paging structures could be freed at once after switching to swapper_pg_dir when early identity mapping is not needed anymore. Reviewed-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2018-10-09s390/kasan: enable stack and global variables access checksVasily Gorbik1-1/+1
By defining KASAN_SHADOW_OFFSET in Kconfig stack and global variables memory access check instrumentation is enabled. gcc version 4.9.2 or newer is also required. Reviewed-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2018-10-09s390/kasan: add initialization code and enable itVasily Gorbik1-0/+23
Kasan needs 1/8 of kernel virtual address space to be reserved as the shadow area. And eventually it requires the shadow memory offset to be known at compile time (passed to the compiler when full instrumentation is enabled). Any value picked as the shadow area offset for 3-level paging would eat up identity mapping on 4-level paging (with 1PB shadow area size). So, the kernel sticks to 3-level paging when kasan is enabled. 3TB border is picked as the shadow offset. The memory layout is adjusted so, that physical memory border does not exceed KASAN_SHADOW_START and vmemmap does not go below KASAN_SHADOW_END. Due to the fact that on s390 paging is set up very late and to cover more code with kasan instrumentation, temporary identity mapping and final shadow memory are set up early. The shadow memory mapping is later carried over to init_mm.pgd during paging_init. For the needs of paging structures allocation and shadow memory population a primitive allocator is used, which simply chops off memory blocks from the end of the physical memory. Kasan currenty doesn't track vmemmap and vmalloc areas. Current memory layout (for 3-level paging, 2GB physical memory). ---[ Identity Mapping ]--- 0x0000000000000000-0x0000000000100000 ---[ Kernel Image Start ]--- 0x0000000000100000-0x0000000002b00000 ---[ Kernel Image End ]--- 0x0000000002b00000-0x0000000080000000 2G <- physical memory border 0x0000000080000000-0x0000030000000000 3070G PUD I ---[ Kasan Shadow Start ]--- 0x0000030000000000-0x0000030010000000 256M PMD RW X <- shadow for 2G memory 0x0000030010000000-0x0000037ff0000000 523776M PTE RO NX <- kasan zero ro page 0x0000037ff0000000-0x0000038000000000 256M PMD RW X <- shadow for 2G modules ---[ Kasan Shadow End ]--- 0x0000038000000000-0x000003d100000000 324G PUD I ---[ vmemmap Area ]--- 0x000003d100000000-0x000003e080000000 ---[ vmalloc Area ]--- 0x000003e080000000-0x000003ff80000000 ---[ Modules Area ]--- 0x000003ff80000000-0x0000040000000000 2G Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>