linux-toradex.git/lib/ioremap.c, branch v5.6-rc6

lib: provide a simple generic ioremap implementation

2019-11-11T20:18:20+00:00

A lot of architectures reuse the same simple ioremap implementation, so
start lifting the most simple variant to lib/ioremap.c.  It provides
ioremap_prot and iounmap, plus a default ioremap that uses prot_noncached,
although that can be overridden by asm/io.h.

Signed-off-by: Christoph Hellwig 
Reviewed-by: Arnd Bergmann 
Reviewed-by: Palmer Dabbelt

mm/ioremap: probe platform for p4d huge map support

2019-07-17T02:23:22+00:00

Finish up what commit c2febafc6773 ("mm: convert generic code to 5-level
paging") started while levelling up P4D huge mapping support at par with
PUD and PMD.  A new arch call back arch_ioremap_p4d_supported() is added
which just maintains status quo (P4D huge map not supported) on x86,
arm64 and powerpc.

When HAVE_ARCH_HUGE_VMAP is enabled its just a simple check from the
arch about the support, hence runtime effects are minimal.

Link: http://lkml.kernel.org/r/1561699231-20991-1-git-send-email-anshuman.khandual@arm.com
Signed-off-by: Anshuman Khandual 
Acked-by: Thomas Gleixner 
Acked-by: Michael Ellerman  (powerpc)
Cc: Catalin Marinas 
Cc: Will Deacon 
Cc: Dave Hansen 
Cc: Andy Lutomirski 
Cc: Peter Zijlstra 
Cc: Ingo Molnar 
Cc: Kirill A. Shutemov 
Cc: Michal Hocko 
Cc: Stephen Rothwell 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm/ioremap: check virtual address alignment while creating huge mappings

2019-07-17T02:23:22+00:00

Virtual address alignment is essential in ensuring correct clearing for
all intermediate level pgtable entries and freeing associated pgtable
pages.  An unaligned address can end up randomly freeing pgtable page
that potentially still contains valid mappings.  Hence also check it's
alignment along with existing phys_addr check.

Signed-off-by: Anshuman Khandual 
Reviewed-by: Catalin Marinas 
Cc: Toshi Kani 
Cc: Will Deacon 
Cc: Chintan Pandya 
Cc: Thomas Gleixner 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

lib/ioremap: ensure break-before-make is used for huge p4d mappings

2018-12-28T20:11:50+00:00

Whilst no architectures actually enable support for huge p4d mappings in
the vmap area, the code that is implemented should be using
break-before-make, as we do for pud and pmd huge entries.

Link: http://lkml.kernel.org/r/1544120495-17438-6-git-send-email-will.deacon@arm.com
Signed-off-by: Will Deacon 
Reviewed-by: Toshi Kani 
Cc: Chintan Pandya 
Cc: Toshi Kani 
Cc: Thomas Gleixner 
Cc: Michal Hocko 
Cc: "H. Peter Anvin" 
Cc: Ingo Molnar 
Cc: Sean Christopherson 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

lib/ioremap: ensure phys_addr actually corresponds to a physical address

2018-12-28T20:11:50+00:00

The current ioremap() code uses a phys_addr variable at each level of page
table, which is confusingly offset by subtracting the base virtual address
being mapped so that adding the current virtual address back on when
iterating through the page table entries gives back the corresponding
physical address.

This is fairly confusing and results in all users of phys_addr having to
add the current virtual address back on.  Instead, this patch just updates
phys_addr when iterating over the page table entries, ensuring that it's
always up-to-date and doesn't require explicit offsetting.

Link: http://lkml.kernel.org/r/1544120495-17438-5-git-send-email-will.deacon@arm.com
Signed-off-by: Will Deacon 
Tested-by: Sean Christopherson 
Reviewed-by: Sean Christopherson 
Cc: Chintan Pandya 
Cc: Toshi Kani 
Cc: Thomas Gleixner 
Cc: Michal Hocko 
Cc: Sean Christopherson 
Cc: "H. Peter Anvin" 
Cc: Ingo Molnar 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

ioremap: rework pXd_free_pYd_page() API

2018-12-28T20:11:50+00:00

The recently merged API for ensuring break-before-make on page-table
entries when installing huge mappings in the vmalloc/ioremap region is
fairly counter-intuitive, resulting in the arch freeing functions (e.g.
pmd_free_pte_page()) being called even on entries that aren't present.
This resulted in a minor bug in the arm64 implementation, giving rise to
spurious VM_WARN messages.

This patch moves the pXd_present() checks out into the core code,
refactoring the callsites at the same time so that we avoid the complex
conjunctions when determining whether or not we can put down a huge
mapping.

Link: http://lkml.kernel.org/r/1544120495-17438-2-git-send-email-will.deacon@arm.com
Signed-off-by: Will Deacon 
Reviewed-by: Toshi Kani 
Suggested-by: Linus Torvalds 
Cc: Chintan Pandya 
Cc: Toshi Kani 
Cc: Thomas Gleixner 
Cc: Michal Hocko 
Cc: "H. Peter Anvin" 
Cc: Ingo Molnar 
Cc: Sean Christopherson 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

ioremap: Update pgtable free interfaces with addr

2018-07-04T19:37:08+00:00

The following kernel panic was observed on ARM64 platform due to a stale
TLB entry.

 1. ioremap with 4K size, a valid pte page table is set.
 2. iounmap it, its pte entry is set to 0.
 3. ioremap the same address with 2M size, update its pmd entry with
    a new value.
 4. CPU may hit an exception because the old pmd entry is still in TLB,
    which leads to a kernel panic.

Commit b6bdb7517c3d ("mm/vmalloc: add interfaces to free unmapped page
table") has addressed this panic by falling to pte mappings in the above
case on ARM64.

To support pmd mappings in all cases, TLB purge needs to be performed
in this case on ARM64.

Add a new arg, 'addr', to pud_free_pmd_page() and pmd_free_pte_page()
so that TLB purge can be added later in seprate patches.

[toshi.kani@hpe.com: merge changes, rewrite patch description]
Fixes: 28ee90fe6048 ("x86/mm: implement free pmd/pte page interfaces")
Signed-off-by: Chintan Pandya 
Signed-off-by: Toshi Kani 
Signed-off-by: Thomas Gleixner 
Cc: mhocko@suse.com
Cc: akpm@linux-foundation.org
Cc: hpa@zytor.com
Cc: linux-mm@kvack.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: Will Deacon 
Cc: Joerg Roedel 
Cc: stable@vger.kernel.org
Cc: Andrew Morton 
Cc: Michal Hocko 
Cc: "H. Peter Anvin" 
Cc: 
Link: https://lkml.kernel.org/r/20180627141348.21777-3-toshi.kani@hpe.com

mm/vmalloc: add interfaces to free unmapped page table

2018-03-23T00:07:01+00:00

On architectures with CONFIG_HAVE_ARCH_HUGE_VMAP set, ioremap() may
create pud/pmd mappings.  A kernel panic was observed on arm64 systems
with Cortex-A75 in the following steps as described by Hanjun Guo.

 1. ioremap a 4K size, valid page table will build,
 2. iounmap it, pte0 will set to 0;
 3. ioremap the same address with 2M size, pgd/pmd is unchanged,
    then set the a new value for pmd;
 4. pte0 is leaked;
 5. CPU may meet exception because the old pmd is still in TLB,
    which will lead to kernel panic.

This panic is not reproducible on x86.  INVLPG, called from iounmap,
purges all levels of entries associated with purged address on x86.  x86
still has memory leak.

The patch changes the ioremap path to free unmapped page table(s) since
doing so in the unmap path has the following issues:

 - The iounmap() path is shared with vunmap(). Since vmap() only
   supports pte mappings, making vunmap() to free a pte page is an
   overhead for regular vmap users as they do not need a pte page freed
   up.

 - Checking if all entries in a pte page are cleared in the unmap path
   is racy, and serializing this check is expensive.

 - The unmap path calls free_vmap_area_noflush() to do lazy TLB purges.
   Clearing a pud/pmd entry before the lazy TLB purges needs extra TLB
   purge.

Add two interfaces, pud_free_pmd_page() and pmd_free_pte_page(), which
clear a given pud/pmd entry and free up a page for the lower level
entries.

This patch implements their stub functions on x86 and arm64, which work
as workaround.

[akpm@linux-foundation.org: fix typo in pmd_free_pte_page() stub]
Link: http://lkml.kernel.org/r/20180314180155.19492-2-toshi.kani@hpe.com
Fixes: e61ce6ade404e ("mm: change ioremap to set up huge I/O mappings")
Reported-by: Lei Li 
Signed-off-by: Toshi Kani 
Cc: Catalin Marinas 
Cc: Wang Xuefeng 
Cc: Will Deacon 
Cc: Hanjun Guo 
Cc: Michal Hocko 
Cc: Thomas Gleixner 
Cc: Ingo Molnar 
Cc: "H. Peter Anvin" 
Cc: Borislav Petkov 
Cc: Matthew Wilcox 
Cc: Chintan Pandya 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Merge tag 'spdx_identifiers-4.14-rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core

2017-11-02T17:04:46+00:00

Pull initial SPDX identifiers from Greg KH:
 "License cleanup: add SPDX license identifiers to some files

  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 "

* tag 'spdx_identifiers-4.14-rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core:
  License cleanup: add SPDX license identifier to uapi header files with a license
  License cleanup: add SPDX license identifier to uapi header files with no license
  License cleanup: add SPDX GPL-2.0 license identifier to files with no license

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

2017-11-02T10:10:55+00:00

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