kernel.git/arch/s390/include/asm/pgtable.h, branch linux-4.16.y

s390/mm: modify pmdp_invalidate to return old value.

2018-02-01T01:18:38Z

It's required to avoid losing dirty and accessed bits. Link: http://lkml.kernel.org/r/20171213105756.69879-8-kirill.shutemov@linux.intel.com Signed-off-by: Martin Schwidefsky Signed-off-by: Kirill A. Shutemov Cc: Vlastimil Babka Cc: Andrea Arcangeli Cc: Michal Hocko Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

Revert "mm: replace p??_write with pte_access_permitted in fault + gup paths"

2017-12-16T02:53:22Z

This reverts commits 5c9d2d5c269c, c7da82b894e9, and e7fe7b5cae90. We'll probably need to revisit this, but basically we should not complicate the get_user_pages_fast() case, and checking the actual page table protection key bits will require more care anyway, since the protection keys depend on the exact state of the VM in question. Particularly when doing a "remote" page lookup (ie in somebody elses VM, not your own), you need to be much more careful than this was. Dave Hansen says: "So, the underlying bug here is that we now a get_user_pages_remote() and then go ahead and do the p*_access_permitted() checks against the current PKRU. This was introduced recently with the addition of the new p??_access_permitted() calls. We have checks in the VMA path for the "remote" gups and we avoid consulting PKRU for them. This got missed in the pkeys selftests because I did a ptrace read, but not a *write*. I also didn't explicitly test it against something where a COW needed to be done" It's also not entirely clear that it makes sense to check the protection key bits at this level at all. But one possible eventual solution is to make the get_user_pages_fast() case just abort if it sees protection key bits set, which makes us fall back to the regular get_user_pages() case, which then has a vma and can do the check there if we want to. We'll see. Somewhat related to this all: what we _do_ want to do some day is to check the PAGE_USER bit - it should obviously always be set for user pages, but it would be a good check to have back. Because we have no generic way to test for it, we lost it as part of moving over from the architecture-specific x86 GUP implementation to the generic one in commit e585513b76f7 ("x86/mm/gup: Switch GUP to the generic get_user_page_fast() implementation"). Cc: Peter Zijlstra Cc: Dan Williams Cc: Dave Hansen Cc: Kirill A. Shutemov Cc: "Jérôme Glisse" Cc: Andrew Morton Cc: Al Viro Signed-off-by: Linus Torvalds

mm: replace pud_write with pud_access_permitted in fault + gup paths

2017-11-30T02:40:42Z

The 'access_permitted' helper is used in the gup-fast path and goes beyond the simple _PAGE_RW check to also: - validate that the mapping is writable from a protection keys standpoint - validate that the pte has _PAGE_USER set since all fault paths where pud_write is must be referencing user-memory. [dan.j.williams@intel.com: fix powerpc compile error] Link: http://lkml.kernel.org/r/151129127237.37405.16073414520854722485.stgit@dwillia2-desk3.amr.corp.intel.com Link: http://lkml.kernel.org/r/151043110453.2842.2166049702068628177.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams Cc: Dave Hansen Cc: "David S. Miller" Cc: Kirill A. Shutemov Cc: Martin Schwidefsky Cc: Heiko Carstens Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm: switch to 'define pmd_write' instead of __HAVE_ARCH_PMD_WRITE

2017-11-30T02:40:42Z

In response to compile breakage introduced by a series that added the pud_write helper to x86, Stephen notes: did you consider using the other paradigm: In arch include files: #define pud_write pud_write static inline int pud_write(pud_t pud) ..... Then in include/asm-generic/pgtable.h: #ifndef pud_write tatic inline int pud_write(pud_t pud) { .... } #endif If you had, then the powerpc code would have worked ... ;-) and many of the other interfaces in include/asm-generic/pgtable.h are protected that way ... Given that some architecture already define pmd_write() as a macro, it's a net reduction to drop the definition of __HAVE_ARCH_PMD_WRITE. Link: http://lkml.kernel.org/r/151129126721.37405.13339850900081557813.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams Suggested-by: Stephen Rothwell Cc: Benjamin Herrenschmidt Cc: "Aneesh Kumar K.V" Cc: Oliver OHalloran Cc: Chris Metcalf Cc: Russell King Cc: Ralf Baechle Cc: "H. Peter Anvin" Cc: Arnd Bergmann Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

License cleanup: add SPDX GPL-2.0 license identifier to files with no license

2017-11-02T10:10:55Z

Many source files in the tree are missing licensing information, which makes it harder for compliance tools to determine the correct license. By default all files without license information are under the default license of the kernel, which is GPL version 2. Update the files which contain no license information with the 'GPL-2.0' SPDX license identifier. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. How this work was done: Patches were generated and checked against linux-4.14-rc6 for a subset of the use cases: - file had no licensing information it it. - file was a */uapi/* one with no licensing information in it, - file was a */uapi/* one with existing licensing information, Further patches will be generated in subsequent months to fix up cases where non-standard license headers were used, and references to license had to be inferred by heuristics based on keywords. The analysis to determine which SPDX License Identifier to be applied to a file was done in a spreadsheet of side by side results from of the output of two independent scanners (ScanCode & Windriver) producing SPDX tag:value files created by Philippe Ombredanne. Philippe prepared the base worksheet, and did an initial spot review of a few 1000 files. The 4.13 kernel was the starting point of the analysis with 60,537 files assessed. Kate Stewart did a file by file comparison of the scanner results in the spreadsheet to determine which SPDX license identifier(s) to be applied to the file. She confirmed any determination that was not immediately clear with lawyers working with the Linux Foundation. Criteria used to select files for SPDX license identifier tagging was: - Files considered eligible had to be source code files. - Make and config files were included as candidates if they contained >5 lines of source - File already had some variant of a license header in it (even if <5 lines). All documentation files were explicitly excluded. The following heuristics were used to determine which SPDX license identifiers to apply. - when both scanners couldn't find any license traces, file was considered to have no license information in it, and the top level COPYING file license applied. For non */uapi/* files that summary was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 11139 and resulted in the first patch in this series. If that file was a */uapi/* path one, it was "GPL-2.0 WITH Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 WITH Linux-syscall-note 930 and resulted in the second patch in this series. - if a file had some form of licensing information in it, and was one of the */uapi/* ones, it was denoted with the Linux-syscall-note if any GPL family license was found in the file or had no licensing in it (per prior point). Results summary: SPDX license identifier # files ---------------------------------------------------|------ GPL-2.0 WITH Linux-syscall-note 270 GPL-2.0+ WITH Linux-syscall-note 169 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17 LGPL-2.1+ WITH Linux-syscall-note 15 GPL-1.0+ WITH Linux-syscall-note 14 ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5 LGPL-2.0+ WITH Linux-syscall-note 4 LGPL-2.1 WITH Linux-syscall-note 3 ((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3 ((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1 and that resulted in the third patch in this series. - when the two scanners agreed on the detected license(s), that became the concluded license(s). - when there was disagreement between the two scanners (one detected a license but the other didn't, or they both detected different licenses) a manual inspection of the file occurred. - In most cases a manual inspection of the information in the file resulted in a clear resolution of the license that should apply (and which scanner probably needed to revisit its heuristics). - When it was not immediately clear, the license identifier was confirmed with lawyers working with the Linux Foundation. - If there was any question as to the appropriate license identifier, the file was flagged for further research and to be revisited later in time. In total, over 70 hours of logged manual review was done on the spreadsheet to determine the SPDX license identifiers to apply to the source files by Kate, Philippe, Thomas and, in some cases, confirmation by lawyers working with the Linux Foundation. Kate also obtained a third independent scan of the 4.13 code base from FOSSology, and compared selected files where the other two scanners disagreed against that SPDX file, to see if there was new insights. The Windriver scanner is based on an older version of FOSSology in part, so they are related. Thomas did random spot checks in about 500 files from the spreadsheets for the uapi headers and agreed with SPDX license identifier in the files he inspected. For the non-uapi files Thomas did random spot checks in about 15000 files. In initial set of patches against 4.14-rc6, 3 files were found to have copy/paste license identifier errors, and have been fixed to reflect the correct identifier. Additionally Philippe spent 10 hours this week doing a detailed manual inspection and review of the 12,461 patched files from the initial patch version early this week with: - a full scancode scan run, collecting the matched texts, detected license ids and scores - reviewing anything where there was a license detected (about 500+ files) to ensure that the applied SPDX license was correct - reviewing anything where there was no detection but the patch license was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied SPDX license was correct This produced a worksheet with 20 files needing minor correction. This worksheet was then exported into 3 different .csv files for the different types of files to be modified. These .csv files were then reviewed by Greg. Thomas wrote a script to parse the csv files and add the proper SPDX tag to the file, in the format that the file expected. This script was further refined by Greg based on the output to detect more types of files automatically and to distinguish between header and source .c files (which need different comment types.) Finally Greg ran the script using the .csv files to generate the patches. Reviewed-by: Kate Stewart Reviewed-by: Philippe Ombredanne Reviewed-by: Thomas Gleixner Signed-off-by: Greg Kroah-Hartman

s390/mm: make pmdp_invalidate() do invalidation only

2017-09-19T06:36:19Z

Commit 227be799c39a ("s390/mm: uninline pmdp_xxx functions from pgtable.h") inadvertently changed the behavior of pmdp_invalidate(), so that it now clears the pmd instead of just marking it as invalid. Fix this by restoring the original behavior. A possible impact of the misbehaving pmdp_invalidate() would be the MADV_DONTNEED races (see commits ced10803 and 58ceeb6b), although we should not have any negative impact on the related dirty/young flags, since those flags are not set by the hardware on s390. Fixes: 227be799c39a ("s390/mm: uninline pmdp_xxx functions from pgtable.h") Cc: # v4.6+ Signed-off-by: Gerald Schaefer Signed-off-by: Martin Schwidefsky

s390/mm: avoid empty zero pages for KVM guests to avoid postcopy hangs

2017-08-29T14:31:27Z

Right now there is a potential hang situation for postcopy migrations, if the guest is enabling storage keys on the target system during the postcopy process. For storage key virtualization, we have to forbid the empty zero page as the storage key is a property of the physical page frame. As we enable storage key handling lazily we then drop all mappings for empty zero pages for lazy refaulting later on. This does not work with the postcopy migration, which relies on the empty zero page never triggering a fault again in the future. The reason is that postcopy migration will simply read a page on the target system if that page is a known zero page to fault in an empty zero page. At the same time postcopy remembers that this page was already transferred - so any future userfault on that page will NOT be retransmitted again to avoid races. If now the guest enters the storage key mode while in postcopy, we will break this assumption of postcopy. The solution is to disable the empty zero page for KVM guests early on and not during storage key enablement. With this change, the postcopy migration process is guaranteed to start after no zero pages are left. As guest pages are very likely not empty zero pages anyway the memory overhead is also pretty small. While at it this also adds proper page table locking to the zero page removal. Signed-off-by: Christian Borntraeger Acked-by: Janosch Frank Cc: stable@vger.kernel.org Signed-off-by: Martin Schwidefsky

s390/mm,vmem: simplify region and segment table allocation code

2017-07-26T06:25:12Z

Reviewed-by: Martin Schwidefsky Reviewed-by: Janosch Frank Signed-off-by: Heiko Carstens Signed-off-by: Martin Schwidefsky

s390/mm: introduce defines to reflect the hardware mmu

2017-07-26T06:25:08Z

Add various defines like e.g. _REGION1_SHIFT to reflect the hardware mmu. We have quite a bit code that does not make use of the Linux memory management primitives but directly modifies page, segment and region values. Most of this is open-coded like e.g. "1UL << 53". In order to clean this up introduce a couple of new defines. The existing Linux memory management defines are changed, so the mapping to the hardware implementation is reflected. Reviewed-by: Martin Schwidefsky Signed-off-by: Heiko Carstens Signed-off-by: Martin Schwidefsky

s390/mm: get rid of ASSEMBLY guards within pgtable.h