kernel.git/arch/s390/include/asm/pgalloc.h, branch linux-4.14.y

s390/mm: add mm_pxd_folded() checks to pxd_free()

2019-12-31T11:37:18Z

[ Upstream commit 2416cefc504ba8ae9b17e3e6b40afc72708f96be ] Unlike pxd_free_tlb(), the pxd_free() functions do not check for folded page tables. This is not an issue so far, as those functions will actually never be called, since no code will reach them when page tables are folded. In order to avoid future issues, and to make the s390 code more similar to other architectures, add mm_pxd_folded() checks, similar to how it is done in pxd_free_tlb(). This was found by testing a patch from from Anshuman Khandual, which is currently discussed on LKML ("mm/debug: Add tests validating architecture page table helpers"). Signed-off-by: Gerald Schaefer Signed-off-by: Vasily Gorbik Signed-off-by: Sasha Levin

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,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: use new mm defines instead of magic values

2017-07-26T06:25:09Z

Reviewed-by: Martin Schwidefsky 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: implement 5 level pages tables

2017-06-12T14:25:54Z

Add the logic to upgrade the page table for a 64-bit process to five levels. This increases the TASK_SIZE from 8PB to 16EB-4K. Signed-off-by: Martin Schwidefsky

s390: Remove VLAIS in ptff() and clear_table()

2016-12-07T06:22:30Z

The ptff() and clear_table() functions use the gcc extension "variable length arrays in structures" (VLAIS) to define in the inline assembler constraints the area of the clobbered memory. This extension will most likely never be supported by LLVM/Clang. Since currently BPF programs are compiled with LLVM, this leads to the following compile errors: $ cd samples/bpf $ make In file included from /root/linux-master/samples/bpf/tracex1_kern.c:8: In file included from ./include/linux/netdevice.h:44: ... In file included from ./arch/s390/include/asm/mmu_context.h:10: ./arch/s390/include/asm/pgalloc.h:30:24: error: fields must have a constant size: 'variable length array in structure' extension will never be supported typedef struct { char _[n]; } addrtype; In file included from /root/linux-master/samples/bpf/tracex1_kern.c:7: In file included from ./include/linux/skbuff.h:18: ... In file included from ./include/linux/jiffies.h:8: In file included from ./include/linux/timex.h:65: ./arch/s390/include/asm/timex.h:105:24: error: fields must have a constant size: 'variable length array in structure' extension will never be supported typedef struct { char _[len]; } addrtype; To fix this do the following: - Convert ptff() into a macro that then uses a fixed size array when expanded. - Convert the clear_table() function and use an inline assembly with fixed size array in a loop. The runtime performance of the new version is even better than the old version (tested with EC12/z13 and gcc 4.8.5/6.2.1 with "-march=z196 -O2"). Reported-by: Zvonko Kosic Signed-off-by: Michael Holzheu Acked-by: Martin Schwidefsky Signed-off-by: Martin Schwidefsky

s390/mm: add shadow gmap support

2016-06-20T07:54:04Z

For a nested KVM guest the outer KVM host needs to create shadow page tables for the nested guest. This patch adds the basic support to the guest address space (gmap) code. For each guest address space the inner KVM host creates, the first outer KVM host needs to create shadow page tables. The address space is identified by the ASCE loaded into the control register 1 at the time the inner SIE instruction for the second nested KVM guest is executed. The outer KVM host creates the shadow tables starting with the table identified by the ASCE on a on-demand basis. The outer KVM host will get repeated faults for all the shadow tables needed to run the second KVM guest. While a shadow page table for the second KVM guest is active the access to the origin region, segment and page tables needs to be restricted for the first KVM guest. For region and segment and page tables the first KVM guest may read the memory, but write attempt has to lead to an unshadow. This is done using the page invalid and read-only bits in the page table of the first KVM guest. If the first guest re-accesses one of the origin pages of a shadow, it gets a fault and the affected parts of the shadow page table hierarchy needs to be removed again. PGSTE tables don't have to be shadowed, as all interpretation assist can't deal with the invalid bits in the shadow pte being set differently than the original ones provided by the first KVM guest. Many bug fixes and improvements by David Hildenbrand. Reviewed-by: David Hildenbrand Signed-off-by: Martin Schwidefsky Signed-off-by: Christian Borntraeger

s390/mm: fix asce_bits handling with dynamic pagetable levels

2016-04-21T07:50:09Z

There is a race with multi-threaded applications between context switch and pagetable upgrade. In switch_mm() a new user_asce is built from mm->pgd and mm->context.asce_bits, w/o holding any locks. A concurrent mmap with a pagetable upgrade on another thread in crst_table_upgrade() could already have set new asce_bits, but not yet the new mm->pgd. This would result in a corrupt user_asce in switch_mm(), and eventually in a kernel panic from a translation exception. Fix this by storing the complete asce instead of just the asce_bits, which can then be read atomically from switch_mm(), so that it either sees the old value or the new value, but no mixture. Both cases are OK. Having the old value would result in a page fault on access to the higher level memory, but the fault handler would see the new mm->pgd, if it was a valid access after the mmap on the other thread has completed. So as worst-case scenario we would have a page fault loop for the racing thread until the next time slice. Also remove dead code and simplify the upgrade/downgrade path, there are no upgrades from 2 levels, and only downgrades from 3 levels for compat tasks. There are also no concurrent upgrades, because the mmap_sem is held with down_write() in do_mmap, so the flush and table checks during upgrade can be removed. Reported-by: Michael Munday Reviewed-by: Martin Schwidefsky Signed-off-by: Gerald Schaefer Signed-off-by: Martin Schwidefsky

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux

2016-03-16T17:47:45Z

Pull s390 updates from Martin Schwidefsky: - Add the CPU id for the new z13s machine - Add a s390 specific XOR template for RAID-5 checksumming based on the XC instruction. Remove all other alternatives, XC is always faster - The merge of our four different stack tracers into a single one - Tidy up the code related to page tables, several large inline functions are now out-of-line. Bloat-o-meter reports ~11K text size reduction - A binary interface for the priviledged CLP instruction to retrieve the hardware view of the installed PCI functions - Improvements for the dasd format code - Bug fixes and cleanups * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: (31 commits) s390/pci: enforce fmb page boundary rule s390: fix floating pointer register corruption (again) s390/cpumf: add missing lpp magic initialization s390: Fix misspellings in comments s390/mm: split arch/s390/mm/pgtable.c s390/mm: uninline pmdp_xxx functions from pgtable.h s390/mm: uninline ptep_xxx functions from pgtable.h s390/pci: add ioctl interface for CLP s390: Use pr_warn instead of pr_warning s390/dasd: remove casts to dasd_*_private s390/dasd: Refactor dasd format functions s390/dasd: Simplify code in format logic s390/dasd: Improve dasd format code s390/percpu: remove this_cpu_cmpxchg_double_4 s390/cpumf: Improve guest detection heuristics s390/fault: merge report_user_fault implementations s390/dis: use correct escape sequence for '%' character s390/kvm: simplify set_guest_storage_key s390/oprofile: add z13/z13s model numbers s390: add z13s model number to z13 elf platform ...