kernel.git/arch/s390/mm, branch linux-3.7.y

s390/gup: fix access_ok() usage in __get_user_pages_fast()

2012-11-13T10:02:28Z

access_ok() returns always "true" on s390. Therefore all access_ok() invocations are rather pointless. However when walking page tables we need to make sure that everything is within bounds of the ASCE limit of the task's address space. So remove the access_ok() call and add the same check we have in get_user_pages_fast(). Reviewed-by: Gerald Schaefer Signed-off-by: Heiko Carstens Signed-off-by: Martin Schwidefsky

s390/gup: add missing TASK_SIZE check to get_user_pages_fast()

2012-11-13T10:02:26Z

When walking page tables we need to make sure that everything is within bounds of the ASCE limit of the task's address space. Otherwise we might calculate e.g. a pud pointer which is not within a pud and dereference it. So check against TASK_SIZE (which is the ASCE limit) before walking page tables. Reviewed-by: Gerald Schaefer Cc: stable@vger.kernel.org Signed-off-by: Heiko Carstens Signed-off-by: Martin Schwidefsky

s390/mm: use pmd_large() instead of pmd_huge()

2012-10-26T14:44:23Z

Without CONFIG_HUGETLB_PAGE, pmd_huge() will always return 0. So pmd_large() should be used instead in places where both transparent huge pages and hugetlbfs pages can occur. Signed-off-by: Gerald Schaefer Signed-off-by: Martin Schwidefsky

s390/mm,vmem: fix vmem_add_mem()/vmem_remove_range()

2012-10-09T12:17:01Z

vmem_add_mem() should only then insert a large page if pmd_none() is true for the specific entry. We might have a leftover from a previous mapping. In addition make vmem_remove_range()'s page table walk code more complete and fix a couple of potential endless loops (which can never happen :). Signed-off-by: Heiko Carstens Signed-off-by: Martin Schwidefsky

s390/vmalloc: have separate modules area

2012-10-09T12:17:01Z

Add a special module area on top of the vmalloc area, which may be only used for modules and bpf jit generated code. This makes sure that inter module branches will always happen without a trampoline and in addition having all the code within a 2GB frame is branch prediction unit friendly. Signed-off-by: Heiko Carstens Signed-off-by: Martin Schwidefsky

s390/mm: fix mapping of read-only kernel text section

2012-10-09T12:16:59Z

Within the identity mapping the kernel text section is mapped read-only. However when mapping the first and last page of the text section we must round upwards and downwards respectively, if only parts of a page belong to the section. Otherwise potential rw data can be mapped read-only. So the rounding must be done just the other way we have it right now. Signed-off-by: Heiko Carstens Signed-off-by: Martin Schwidefsky

s390/mm: add page table dumper

2012-10-09T12:16:58Z

This is more or less the same as the x86 page table dumper which was merged four years ago: 926e5392 "x86: add code to dump the (kernel) page tables for visual inspection by kernel developers". We add a file at /sys/kernel/debug/kernel_page_tables for debugging purposes so it's quite easy to see the kernel page table layout and possible odd mappings: ---[ Identity Mapping ]--- 0x0000000000000000-0x0000000000100000 1M PTE RW ---[ Kernel Image Start ]--- 0x0000000000100000-0x0000000000800000 7M PMD RO 0x0000000000800000-0x00000000008a9000 676K PTE RO 0x00000000008a9000-0x0000000000900000 348K PTE RW 0x0000000000900000-0x0000000001500000 12M PMD RW ---[ Kernel Image End ]--- 0x0000000001500000-0x0000000280000000 10219M PMD RW 0x0000000280000000-0x000003d280000000 3904G PUD I ---[ vmemmap Area ]--- 0x000003d280000000-0x000003d288c00000 140M PTE RW 0x000003d288c00000-0x000003d300000000 1908M PMD I 0x000003d300000000-0x000003e000000000 52G PUD I ---[ vmalloc Area ]--- 0x000003e000000000-0x000003e000009000 36K PTE RW 0x000003e000009000-0x000003e0000ee000 916K PTE I 0x000003e0000ee000-0x000003e000146000 352K PTE RW 0x000003e000146000-0x000003e000200000 744K PTE I 0x000003e000200000-0x000003e080000000 2046M PMD I 0x000003e080000000-0x0000040000000000 126G PUD I This usually makes only sense for kernel developers. The output with CONFIG_DEBUG_PAGEALLOC is not very helpful, because of the huge number of mapped out pages, however I decided for the time being to not add a !DEBUG_PAGEALLOC dependency. Maybe it's helpful for somebody even with that option. Signed-off-by: Heiko Carstens Signed-off-by: Martin Schwidefsky

s390/mm,pageattr: remove superfluous EXPORT_SYMBOLs

2012-10-09T12:16:57Z

Remove some EXPORT_SYMBOLs. There is no module code anywhere which calls these pageattr functions. Signed-off-by: Heiko Carstens Signed-off-by: Martin Schwidefsky

s390/mm,pageattr: add more page table walk sanity checks

2012-10-09T12:16:57Z

The current page table walk code in pageattr.c only checks for large pages while walking the kernel page table, but happily assumes that everything else is just fine. Add more checks so we never access invalid memory regions. Reviewed-by: Gerald Schaefer Signed-off-by: Heiko Carstens Signed-off-by: Martin Schwidefsky

s390/mm: fix pmd_huge() usage for kernel mapping

2012-10-09T12:16:56Z

pmd_huge() will always return 0 on !HUGETLBFS, however we use that helper function when walking the kernel page tables to decide if we have a 1MB page frame or not. Since we create 1MB frames for the kernel 1:1 mapping independently of HUGETLBFS this can lead to incorrect storage accesses since the code can assume that we have a pointer to a page table instead of a pointer to a 1MB frame. Fix this by adding a pmd_large() primitive like other architectures have it already and remove all references to HUGETLBFS/HUGETLBPAGE from the code that walks kernel page tables. Reviewed-by: Gerald Schaefer Signed-off-by: Heiko Carstens Signed-off-by: Martin Schwidefsky