Christophe Leroy 76af8126a6 mm: ptdump: fix build failure
commit 458376913d86bed2fb781b4952eb6861675ef3be upstream.

READ_ONCE() cannot be used for reading PTEs.  Use ptep_get() instead, to
avoid the following errors:

    CC      mm/ptdump.o
  In file included from <command-line>:
  mm/ptdump.c: In function 'ptdump_pte_entry':
  include/linux/compiler_types.h:320:38: error: call to '__compiletime_assert_207' declared with attribute error: Unsupported access size for {READ,WRITE}_ONCE().
    320 |  _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
        |                                      ^
  include/linux/compiler_types.h:301:4: note: in definition of macro '__compiletime_assert'
    301 |    prefix ## suffix();    \
        |    ^~~~~~
  include/linux/compiler_types.h:320:2: note: in expansion of macro '_compiletime_assert'
    320 |  _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
        |  ^~~~~~~~~~~~~~~~~~~
  include/asm-generic/rwonce.h:36:2: note: in expansion of macro 'compiletime_assert'
     36 |  compiletime_assert(__native_word(t) || sizeof(t) == sizeof(long long), \
        |  ^~~~~~~~~~~~~~~~~~
  include/asm-generic/rwonce.h:49:2: note: in expansion of macro 'compiletime_assert_rwonce_type'
     49 |  compiletime_assert_rwonce_type(x);    \
        |  ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  mm/ptdump.c:114:14: note: in expansion of macro 'READ_ONCE'
    114 |  pte_t val = READ_ONCE(*pte);
        |              ^~~~~~~~~
  make[2]: *** [mm/ptdump.o] Error 1

See commit 481e980a7c19 ("mm: Allow arches to provide ptep_get()") and
commit c0e1c8c22beb ("powerpc/8xx: Provide ptep_get() with 16k pages")
for details.

Link: https://lkml.kernel.org/r/912b349e2bcaa88939904815ca0af945740c6bd4.1618478922.git.christophe.leroy@csgroup.eu
Fixes: 30d621f6723b ("mm: add generic ptdump")
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Steven Price <steven.price@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-04-21 13:00:57 +02:00
2021-04-21 13:00:57 +02:00
2020-10-17 11:18:18 -07:00
2021-04-16 11:43:22 +02:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.
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