Commit Graph

1027361 Commits

Author SHA1 Message Date
Marco Elver
540540d06e kcov: add __no_sanitize_coverage to fix noinstr for all architectures
Until now no compiler supported an attribute to disable coverage
instrumentation as used by KCOV.

To work around this limitation on x86, noinstr functions have their
coverage instrumentation turned into nops by objtool.  However, this
solution doesn't scale automatically to other architectures, such as
arm64, which are migrating to use the generic entry code.

Clang [1] and GCC [2] have added support for the attribute recently.
[1] 280333021e
[2] https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=cec4d4a6782c9bd8d071839c50a239c49caca689
The changes will appear in Clang 13 and GCC 12.

Add __no_sanitize_coverage for both compilers, and add it to noinstr.

Note: In the Clang case, __has_feature(coverage_sanitizer) is only true if
the feature is enabled, and therefore we do not require an additional
defined(CONFIG_KCOV) (like in the GCC case where __has_attribute(..) is
always true) to avoid adding redundant attributes to functions if KCOV is
off.  That being said, compilers that support the attribute will not
generate errors/warnings if the attribute is redundantly used; however,
where possible let's avoid it as it reduces preprocessed code size and
associated compile-time overheads.

[elver@google.com: Implement __has_feature(coverage_sanitizer) in Clang]
  Link: https://lkml.kernel.org/r/20210527162655.3246381-1-elver@google.com
[elver@google.com: add comment explaining __has_feature() in Clang]
  Link: https://lkml.kernel.org/r/20210527194448.3470080-1-elver@google.com

Link: https://lkml.kernel.org/r/20210525175819.699786-1-elver@google.com
Signed-off-by: Marco Elver <elver@google.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Miguel Ojeda <ojeda@kernel.org>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Will Deacon <will@kernel.org>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
Cc: Arvind Sankar <nivedita@alum.mit.edu>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Sami Tolvanen <samitolvanen@google.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-07-01 11:06:06 -07:00
Alexey Dobriyan
bae7702a17 exec: remove checks in __register_bimfmt()
Delete NULL check, all callers pass valid pointer.

Delete ->load_binary check -- failure to provide hook in a custom module
will be very noticeable at the very first execve call.

Link: https://lkml.kernel.org/r/YK1Gy1qXaLAR+tPl@localhost.localdomain
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-07-01 11:06:06 -07:00
Al Viro
97c885d585 x86: signal: don't do sas_ss_reset() until we are certain that sigframe won't be abandoned
Currently we handle SS_AUTODISARM as soon as we have stored the altstack
settings into sigframe - that's the point when we have set the things up
for eventual sigreturn to restore the old settings.  And if we manage to
set the sigframe up (we are not done with that yet), everything's fine.
However, in case of failure we end up with sigframe-to-be abandoned and
SIGSEGV force-delivered.  And in that case we end up with inconsistent
rules - late failures have altstack reset, early ones do not.

It's trivial to get consistent behaviour - just handle SS_AUTODISARM once
we have set the sigframe up and are committed to entering the handler,
i.e.  in signal_delivered().

Link: https://lore.kernel.org/lkml/20200404170604.GN23230@ZenIV.linux.org.uk/
Link: https://github.com/ClangBuiltLinux/linux/issues/876
Link: https://lkml.kernel.org/r/20210422230846.1756380-1-ndesaulniers@google.com
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Tested-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-07-01 11:06:06 -07:00
Chung-Chiang Cheng
c3eb84092b hfsplus: report create_date to kstat.btime
The create_date field of inode in hfsplus is corresponding to
kstat.btime and could be reported in statx.

Link: https://lkml.kernel.org/r/20210416172147.8736-1-cccheng@synology.com
Signed-off-by: Chung-Chiang Cheng <cccheng@synology.com>
Reviewed-by: Viacheslav Dubeyko <slava@dubeyko.com>
Cc: Christian Brauner <christian.brauner@ubuntu.com>
Cc: James Morris <jamorris@linux.microsoft.com>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-07-01 11:06:06 -07:00
Zhen Lei
7dcae11f4c hfsplus: remove unnecessary oom message
Fixes scripts/checkpatch.pl warning:
WARNING: Possible unnecessary 'out of memory' message

Remove it can help us save a bit of memory.

Link: https://lkml.kernel.org/r/20210617084944.1279-1-thunder.leizhen@huawei.com
Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-07-01 11:06:06 -07:00
Colin Ian King
f4048e5aa1 nilfs2: remove redundant continue statement in a while-loop
The continue statement at the end of the while-loop is redundant,
remove it.

Addresses-Coverity: ("Continue has no effect")
Link: https://lkml.kernel.org/r/20210621100519.10257-1-colin.king@canonical.com
Link: https://lkml.kernel.org/r/1624557664-17159-1-git-send-email-konishi.ryusuke@gmail.com
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-07-01 11:06:06 -07:00
Barry Song
66ce75144d kprobes: remove duplicated strong free_insn_page in x86 and s390
free_insn_page() in x86 and s390 is same with the common weak function in
kernel/kprobes.c.  Plus, the comment "Recover page to RW mode before
releasing it" in x86 seems insensible to be there since resetting mapping
is done by common code in vfree() of module_memfree().  So drop these two
duplicated strong functions and related comment, then mark the common one
in kernel/kprobes.c strong.

Link: https://lkml.kernel.org/r/20210608065736.32656-1-song.bao.hua@hisilicon.com
Signed-off-by: Barry Song <song.bao.hua@hisilicon.com>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: "Naveen N. Rao" <naveen.n.rao@linux.ibm.com>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Qi Liu <liuqi115@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-07-01 11:06:06 -07:00
Andrew Halaney
86d1919a4f init: print out unknown kernel parameters
It is easy to foobar setting a kernel parameter on the command line
without realizing it, there's not much output that you can use to assess
what the kernel did with that parameter by default.

Make it a little more explicit which parameters on the command line
_looked_ like a valid parameter for the kernel, but did not match anything
and ultimately got tossed to init.  This is very similar to the unknown
parameter message received when loading a module.

This assumes the parameters are processed in a normal fashion, some
parameters (dyndbg= for example) don't register their parameter with the
rest of the kernel's parameters, and therefore always show up in this list
(and are also given to init - like the rest of this list).

Another example is BOOT_IMAGE= is highlighted as an offender, which it
technically is, but is passed by LILO and GRUB so most systems will see
that complaint.

An example output where "foobared" and "unrecognized" are intentionally
invalid parameters:

  Kernel command line: BOOT_IMAGE=/boot/vmlinuz-5.12-dirty debug log_buf_len=4M foobared unrecognized=foo
  Unknown command line parameters: foobared BOOT_IMAGE=/boot/vmlinuz-5.12-dirty unrecognized=foo

Link: https://lkml.kernel.org/r/20210511211009.42259-1-ahalaney@redhat.com
Signed-off-by: Andrew Halaney <ahalaney@redhat.com>
Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Suggested-by: Borislav Petkov <bp@suse.de>
Acked-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-07-01 11:06:06 -07:00
Guenter Roeck
46b85bf967 checkpatch: do not complain about positive return values starting with EPOLL
checkpatch complains about positive return values of poll functions.
Example:

WARNING: return of an errno should typically be negative (ie: return -EPOLLIN)
+		return EPOLLIN;

Poll functions return positive values.  The defines for the return values
of poll functions all start with EPOLL, resulting in a number of false
positives.  An often used workaround is to assign poll function return
values to variables and returning that variable, but that is a less than
perfect solution.

There is no error definition which starts with EPOLL, so it is safe to
omit the warning for return values starting with EPOLL.

Link: https://lkml.kernel.org/r/20210622004334.638680-1-linux@roeck-us.net
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Acked-by: Joe Perches <joe@perches.com>
Cc: Ricardo Ribalda <ribalda@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-07-01 11:06:06 -07:00
Joe Perches
690786511b checkpatch: improve the indented label test
checkpatch identifies a label only when a terminating colon
immediately follows an identifier.

Bitfield definitions can appear to be labels so ignore any
spaces between the identifier terminating colon and any digit
that may be used to define a bitfield length.

Miscellanea:

o Improve the initial checkpatch comment
o Use the more typical '&&' instead of 'and'
o Require the initial label character to be a non-digit
  (Can't use $Ident here because $Ident allows ## concatenation)
o Use $sline instead of $line to ignore comments
o Use '$sline !~ /.../' instead of '!($line =~ /.../)'

Link: https://lkml.kernel.org/r/b54d673e7cde7de5de0c9ba4dd57dd0858580ca4.camel@perches.com
Signed-off-by: Joe Perches <joe@perches.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Manikishan Ghantasala <manikishanghantasala@gmail.com>
Cc: Alex Elder <elder@ieee.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-07-01 11:06:06 -07:00
Guenter Roeck
f9363b31d7 checkpatch: scripts/spdxcheck.py now requires python3
Since commit d0259c42ab ("spdxcheck.py: Use Python 3"), spdxcheck.py
explicitly expects to run as python3 script.  If "python" still points to
python v2.7 and the script is executed with "python scripts/spdxcheck.py",
the following error may be seen even if git-python is installed for
python3.

Traceback (most recent call last):
  File "scripts/spdxcheck.py", line 10, in <module>
    import git
ImportError: No module named git

To fix the problem, check for the existence of python3, check if
the script is executable and not just for its existence, and execute
it directly.

Link: https://lkml.kernel.org/r/20210505211720.447111-1-linux@roeck-us.net
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Cc: Joe Perches <joe@perches.com>
Cc: Bert Vermeulen <bert@biot.com>
Cc: Dwaipayan Ray <dwaipayanray1@gmail.com>
Cc: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-07-01 11:06:06 -07:00
Dimitri John Ledkov
2c484419ef lib/decompress_unlz4.c: correctly handle zero-padding around initrds.
lz4 compatible decompressor is simple.  The format is underspecified and
relies on EOF notification to determine when to stop.  Initramfs buffer
format[1] explicitly states that it can have arbitrary number of zero
padding.  Thus when operating without a fill function, be extra careful to
ensure that sizes less than 4, or apperantly empty chunksizes are treated
as EOF.

To test this I have created two cpio initrds, first a normal one,
main.cpio.  And second one with just a single /test-file with content
"second" second.cpio.  Then i compressed both of them with gzip, and with
lz4 -l.  Then I created a padding of 4 bytes (dd if=/dev/zero of=pad4 bs=1
count=4).  To create four testcase initrds:

 1) main.cpio.gzip + extra.cpio.gzip = pad0.gzip
 2) main.cpio.lz4  + extra.cpio.lz4 = pad0.lz4
 3) main.cpio.gzip + pad4 + extra.cpio.gzip = pad4.gzip
 4) main.cpio.lz4  + pad4 + extra.cpio.lz4 = pad4.lz4

The pad4 test-cases replicate the initrd load by grub, as it pads and
aligns every initrd it loads.

All of the above boot, however /test-file was not accessible in the initrd
for the testcase #4, as decoding in lz4 decompressor failed.  Also an
error message printed which usually is harmless.

Whith a patched kernel, all of the above testcases now pass, and
/test-file is accessible.

This fixes lz4 initrd decompress warning on every boot with grub.  And
more importantly this fixes inability to load multiple lz4 compressed
initrds with grub.  This patch has been shipping in Ubuntu kernels since
January 2021.

[1] ./Documentation/driver-api/early-userspace/buffer-format.rst

BugLink: https://bugs.launchpad.net/bugs/1835660
Link: https://lore.kernel.org/lkml/20210114200256.196589-1-xnox@ubuntu.com/ # v0
Link: https://lkml.kernel.org/r/20210513104831.432975-1-dimitri.ledkov@canonical.com
Signed-off-by: Dimitri John Ledkov <dimitri.ledkov@canonical.com>
Cc: Kyungsik Lee <kyungsik.lee@lge.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Bongkyu Kim <bongkyu.kim@lge.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Sven Schmidt <4sschmid@informatik.uni-hamburg.de>
Cc: Rajat Asthana <thisisrast7@gmail.com>
Cc: Nick Terrell <terrelln@fb.com>
Cc: Gao Xiang <hsiangkao@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-07-01 11:06:06 -07:00
Rajat Asthana
7fde9d6e83 lz4_decompress: declare LZ4_decompress_safe_withPrefix64k static
Declare LZ4_decompress_safe_withPrefix64k as static to fix sparse
warning:

> warning: symbol 'LZ4_decompress_safe_withPrefix64k' was not declared.
> Should it be static?

Link: https://lkml.kernel.org/r/20210511154345.610569-1-thisisrast7@gmail.com
Signed-off-by: Rajat Asthana <thisisrast7@gmail.com>
Reviewed-by: Nick Terrell <terrelln@fb.com>
Cc: Gao Xiang <hsiangkao@redhat.com>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-07-01 11:06:05 -07:00
Andy Shevchenko
4c52729377 kernel.h: split out kstrtox() and simple_strtox() to a separate header
kernel.h is being used as a dump for all kinds of stuff for a long time.
Here is the attempt to start cleaning it up by splitting out kstrtox() and
simple_strtox() helpers.

At the same time convert users in header and lib folders to use new
header.  Though for time being include new header back to kernel.h to
avoid twisted indirected includes for existing users.

[andy.shevchenko@gmail.com: fix documentation references]
  Link: https://lkml.kernel.org/r/20210615220003.377901-1-andy.shevchenko@gmail.com

Link: https://lkml.kernel.org/r/20210611185815.44103-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Francis Laniel <laniel_francis@privacyrequired.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Kars Mulder <kerneldev@karsmulder.nl>
Cc: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: Anna Schumaker <anna.schumaker@netapp.com>
Cc: "J. Bruce Fields" <bfields@fieldses.org>
Cc: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-07-01 11:06:05 -07:00
Matteo Croce
ce71efd039 lib/test_string.c: allow module removal
The test_string module can't be removed because it lacks an exit hook.
Since there is no reason for it to be permanent, add an empty one to allow
module removal.

Link: https://lkml.kernel.org/r/20210616234503.28678-1-mcroce@linux.microsoft.com
Signed-off-by: Matteo Croce <mcroce@microsoft.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-07-01 11:06:05 -07:00
Alexey Dobriyan
ad65dcef3a lib: uninline simple_strtoull()
Gcc inlines simple_strtoull() too agressively.

Given that all 4 signatures match, everything very efficiently calls or
tailcalls into simple_strtoull():

	ffffffff81da0240 <simple_strtoll>:
	ffffffff81da0240:       80 3f 2d                cmp    BYTE PTR [rdi],0x2d
	ffffffff81da0243:       74 05                   je     ffffffff81da024a <simple_strtoll+0xa>
	ffffffff81da0245:       e9 76 ff ff ff          jmp    simple_strtoull
	ffffffff81da024a:       48 83 c7 01             add    rdi,0x1
	ffffffff81da024e:       e8 6d ff ff ff          call   simple_strtoull
	ffffffff81da0253:       48 f7 d8                neg    rax
	ffffffff81da0256:       c3                      ret

Space savings (on F34-ish .config)

	add/remove: 0/0 grow/shrink: 1/3 up/down: 52/-313 (-261)
	Function                                     old     new   delta
	vsscanf                                     2167    2219     +52
	simple_strtoul                                72       2     -70
	simple_strtoll                               143      23    -120
	simple_strtol                                143      20    -123

Link: https://lkml.kernel.org/r/YMO2zoOQk2eF34tn@localhost.localdomain
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-07-01 11:06:05 -07:00
Alexey Dobriyan
1a58be6277 lib: memscan() fixlet
Generic version doesn't trucate second argument to char.

Older brother memchr() does as do s390, sparc and i386 assembly versions.

Fortunately, no code passes c >= 256.

Link: https://lkml.kernel.org/r/YLv4cCf0t5UPdyK+@localhost.localdomain
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-07-01 11:06:05 -07:00
Zhen Lei
478485f6c0 lib/mpi: fix spelling mistakes
Fix some spelling mistakes in comments:
flaged ==> flagged
bufer ==> buffer
multipler ==> multiplier
MULTIPLER ==> MULTIPLIER
leaset ==> least
chnage ==> change

Link: https://lkml.kernel.org/r/20210604074401.12198-1-thunder.leizhen@huawei.com
Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-07-01 11:06:05 -07:00
Zhen Lei
05911c5d96 lib/decompressors: fix spelling mistakes
Fix some spelling mistakes in comments:
sentinal ==> sentinel
compresed ==> compressed
dependeny ==> dependency
immediatelly ==> immediately
dervied ==> derived
splitted ==> split
nore ==> not
independed ==> independent
asumed ==> assumed

Link: https://lkml.kernel.org/r/20210604085656.12257-1-thunder.leizhen@huawei.com
Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-07-01 11:06:05 -07:00
Trent Piepho
b6c75c4afc lib/math/rational: add Kunit test cases
Adds a number of test cases that cover a range of possible code paths.

[akpm@linux-foundation.org: remove non-ascii characters, fix whitespace]
[colin.king@canonical.com: fix spelling mistake "demominator" -> "denominator"]
  Link: https://lkml.kernel.org/r/20210526085049.6393-1-colin.king@canonical.com

Link: https://lkml.kernel.org/r/20210525144250.214670-2-tpiepho@gmail.com
Signed-off-by: Trent Piepho <tpiepho@gmail.com>
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Daniel Latypov <dlatypov@google.com>
Cc: Oskar Schirmer <oskar@scara.com>
Cc: Yiyuan Guo <yguoaz@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-07-01 11:06:05 -07:00
Trent Piepho
65a0d3c146 lib/math/rational.c: fix divide by zero
If the input is out of the range of the allowed values, either larger than
the largest value or closer to zero than the smallest non-zero allowed
value, then a division by zero would occur.

In the case of input too large, the division by zero will occur on the
first iteration.  The best result (largest allowed value) will be found by
always choosing the semi-convergent and excluding the denominator based
limit when finding it.

In the case of the input too small, the division by zero will occur on the
second iteration.  The numerator based semi-convergent should not be
calculated to avoid the division by zero.  But the semi-convergent vs
previous convergent test is still needed, which effectively chooses
between 0 (the previous convergent) vs the smallest allowed fraction (best
semi-convergent) as the result.

Link: https://lkml.kernel.org/r/20210525144250.214670-1-tpiepho@gmail.com
Fixes: 323dd2c3ed ("lib/math/rational.c: fix possible incorrect result from rational fractions helper")
Signed-off-by: Trent Piepho <tpiepho@gmail.com>
Reported-by: Yiyuan Guo <yguoaz@gmail.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Oskar Schirmer <oskar@scara.com>
Cc: Daniel Latypov <dlatypov@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-07-01 11:06:05 -07:00
Andy Shevchenko
cc72181a65 seq_file: drop unused *_escape_mem_ascii()
There are no more users of the seq_escape_mem_ascii() followed by
string_escape_mem_ascii().

Remove them for good.

Link: https://lkml.kernel.org/r/20210504180819.73127-16-andriy.shevchenko@linux.intel.com
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Chuck Lever <chuck.lever@oracle.com>
Cc: "J. Bruce Fields" <bfields@fieldses.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-07-01 11:06:05 -07:00
Andy Shevchenko
c0546391c2 nfsd: avoid non-flexible API in seq_quote_mem()
The seq_escape_mem_ascii() is completely non-flexible and shouldn't be
used.  Replace it with properly called seq_escape_mem().

Link: https://lkml.kernel.org/r/20210504180819.73127-15-andriy.shevchenko@linux.intel.com
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Chuck Lever <chuck.lever@oracle.com>
Cc: "J. Bruce Fields" <bfields@fieldses.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-07-01 11:06:05 -07:00
Andy Shevchenko
fc3de02eae seq_file: convert seq_escape() to use seq_escape_str()
Convert seq_escape() to use seq_escape_str() rather than open coding it.

Note, for now we leave it as an exported symbol due to some old code that
can't tolerate ctype.h being (indirectly) included.

Link: https://lkml.kernel.org/r/20210504180819.73127-14-andriy.shevchenko@linux.intel.com
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Chuck Lever <chuck.lever@oracle.com>
Cc: "J. Bruce Fields" <bfields@fieldses.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-07-01 11:06:05 -07:00
Andy Shevchenko
e7ed4a3b92 seq_file: add seq_escape_str() as replica of string_escape_str()
In some cases we want to escape characters from NULL-terminated strings.
Add seq_escape_str() as replica of string_escape_str() for that.

Link: https://lkml.kernel.org/r/20210504180819.73127-13-andriy.shevchenko@linux.intel.com
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Chuck Lever <chuck.lever@oracle.com>
Cc: "J. Bruce Fields" <bfields@fieldses.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-07-01 11:06:05 -07:00
Andy Shevchenko
1d31aa172a seq_file: introduce seq_escape_mem()
Introduce seq_escape_mem() to allow users to pass additional parameters to
string_escape_mem().

Link: https://lkml.kernel.org/r/20210504180819.73127-12-andriy.shevchenko@linux.intel.com
Suggested-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Chuck Lever <chuck.lever@oracle.com>
Cc: "J. Bruce Fields" <bfields@fieldses.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-07-01 11:06:05 -07:00
Andy Shevchenko
be613b4025 MAINTAINERS: add myself as designated reviewer for generic string library
Add myself as designated reviewer for generic string library.

Link: https://lkml.kernel.org/r/20210504180819.73127-11-andriy.shevchenko@linux.intel.com
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Chuck Lever <chuck.lever@oracle.com>
Cc: "J. Bruce Fields" <bfields@fieldses.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-07-01 11:06:05 -07:00
Andy Shevchenko
259fa5d7d8 lib/test-string_helpers: add test cases for new features
We have got new flags and hence new features of string_escape_mem().
Add test cases for that.

Link: https://lkml.kernel.org/r/20210504180819.73127-10-andriy.shevchenko@linux.intel.com
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Chuck Lever <chuck.lever@oracle.com>
Cc: "J. Bruce Fields" <bfields@fieldses.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-07-01 11:06:05 -07:00
Andy Shevchenko
69325698df lib/test-string_helpers: get rid of trailing comma in terminators
Terminators by definition shouldn't accept anything behind.  Make them
robust by removing trailing commas.

Link: https://lkml.kernel.org/r/20210504180819.73127-9-andriy.shevchenko@linux.intel.com
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Chuck Lever <chuck.lever@oracle.com>
Cc: "J. Bruce Fields" <bfields@fieldses.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-07-01 11:06:04 -07:00
Andy Shevchenko
229563b196 lib/test-string_helpers: print flags in hexadecimal format
Since flags are bitmapped, it's better to print them in hexadecimal
format.

Link: https://lkml.kernel.org/r/20210504180819.73127-8-andriy.shevchenko@linux.intel.com
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Chuck Lever <chuck.lever@oracle.com>
Cc: "J. Bruce Fields" <bfields@fieldses.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-07-01 11:06:04 -07:00
Andy Shevchenko
aec0d0966f lib/string_helpers: allow to append additional characters to be escaped
Introduce a new flag to append additional characters, passed in 'only'
parameter, to be escaped if they fall in the corresponding class.

Link: https://lkml.kernel.org/r/20210504180819.73127-7-andriy.shevchenko@linux.intel.com
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Chuck Lever <chuck.lever@oracle.com>
Cc: "J. Bruce Fields" <bfields@fieldses.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-07-01 11:06:04 -07:00
Andy Shevchenko
0362c27fb3 lib/string_helpers: introduce ESCAPE_NAP to escape non-ASCII and non-printable
Some users may want to have an ASCII based filter for printable only
characters, provided by conjunction of isascii() and isprint() functions.

Here is the addition of a such.

Link: https://lkml.kernel.org/r/20210504180819.73127-6-andriy.shevchenko@linux.intel.com
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Chuck Lever <chuck.lever@oracle.com>
Cc: "J. Bruce Fields" <bfields@fieldses.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-07-01 11:06:04 -07:00
Andy Shevchenko
a080978335 lib/string_helpers: introduce ESCAPE_NA for escaping non-ASCII
Some users may want to have an ASCII based filter, provided by isascii()
function.  Here is the addition of a such.

Link: https://lkml.kernel.org/r/20210504180819.73127-5-andriy.shevchenko@linux.intel.com
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Chuck Lever <chuck.lever@oracle.com>
Cc: "J. Bruce Fields" <bfields@fieldses.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-07-01 11:06:04 -07:00
Andy Shevchenko
7e5969aeb7 lib/string_helpers: drop indentation level in string_escape_mem()
The only one conditional is left on the upper level, move the rest to the
same level and drop indentation level.  No functional changes.

Link: https://lkml.kernel.org/r/20210504180819.73127-4-andriy.shevchenko@linux.intel.com
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Chuck Lever <chuck.lever@oracle.com>
Cc: "J. Bruce Fields" <bfields@fieldses.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-07-01 11:06:04 -07:00
Andy Shevchenko
62519b882d lib/string_helpers: move ESCAPE_NP check inside 'else' branch in a loop
Refactor code to have better readability by moving ESCAPE_NP handling
inside 'else' branch in the loop.

No functional change intended.

Link: https://lkml.kernel.org/r/20210504180819.73127-3-andriy.shevchenko@linux.intel.com
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Chuck Lever <chuck.lever@oracle.com>
Cc: "J. Bruce Fields" <bfields@fieldses.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-07-01 11:06:04 -07:00
Andy Shevchenko
994b69703e lib/string_helpers: switch to use BIT() macro
Patch series "lib/string_helpers: get rid of ugly *_escape_mem_ascii()", v3.

Get rid of ugly *_escape_mem_ascii() API since it's not flexible and has
the only single user.  Provide better approach based on usage of the
string_escape_mem() with appropriate flags.

Test cases has been expanded accordingly to cover new functionality.

This patch (of 15):

Switch to use BIT() macro for flag definitions.  No changes implied.

Link: https://lkml.kernel.org/r/20210504180819.73127-1-andriy.shevchenko@linux.intel.com
Link: https://lkml.kernel.org/r/20210504180819.73127-2-andriy.shevchenko@linux.intel.com
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: "J. Bruce Fields" <bfields@fieldses.org>
Cc: Chuck Lever <chuck.lever@oracle.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-07-01 11:06:04 -07:00
Zhen Lei
92aeda50d4 lib: decompress_bunzip2: remove an unneeded semicolon
The semicolon immediately following '}' is unneeded.

Link: https://lkml.kernel.org/r/20210508094926.2889-1-thunder.leizhen@huawei.com
Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-07-01 11:06:04 -07:00
Andy Shevchenko
f39650de68 kernel.h: split out panic and oops helpers
kernel.h is being used as a dump for all kinds of stuff for a long time.
Here is the attempt to start cleaning it up by splitting out panic and
oops helpers.

There are several purposes of doing this:
- dropping dependency in bug.h
- dropping a loop by moving out panic_notifier.h
- unload kernel.h from something which has its own domain

At the same time convert users tree-wide to use new headers, although for
the time being include new header back to kernel.h to avoid twisted
indirected includes for existing users.

[akpm@linux-foundation.org: thread_info.h needs limits.h]
[andriy.shevchenko@linux.intel.com: ia64 fix]
  Link: https://lkml.kernel.org/r/20210520130557.55277-1-andriy.shevchenko@linux.intel.com

Link: https://lkml.kernel.org/r/20210511074137.33666-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Co-developed-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Mike Rapoport <rppt@linux.ibm.com>
Acked-by: Corey Minyard <cminyard@mvista.com>
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Kees Cook <keescook@chromium.org>
Acked-by: Wei Liu <wei.liu@kernel.org>
Acked-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Sebastian Reichel <sre@kernel.org>
Acked-by: Luis Chamberlain <mcgrof@kernel.org>
Acked-by: Stephen Boyd <sboyd@kernel.org>
Acked-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Acked-by: Helge Deller <deller@gmx.de> # parisc
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-07-01 11:06:04 -07:00
Andy Shevchenko
070c46505a drm: include only needed headers in ascii85.h
The ascii85.h is user of exactly two headers, i.e.  math.h and types.h.
There is no need to carry on entire kernel.h.

Link: https://lkml.kernel.org/r/20210611185915.44181-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-07-01 11:06:04 -07:00
Jiapeng Chong
9a52c5f3c8 sysctl: remove redundant assignment to first
Variable first is set to '0', but this value is never read as it is not
used later on, hence it is a redundant assignment and can be removed.

Clean up the following clang-analyzer warning:

kernel/sysctl.c:1562:4: warning: Value stored to 'first' is never read
[clang-analyzer-deadcode.DeadStores].

Link: https://lkml.kernel.org/r/1620469990-22182-1-git-send-email-jiapeng.chong@linux.alibaba.com
Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Acked-by: Luis Chamberlain <mcgrof@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Iurii Zaikin <yzaikin@google.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Martin KaFai Lau <kafai@fb.com>
Cc: Song Liu <songliubraving@fb.com>
Cc: Yonghong Song <yhs@fb.com>
Cc: John Fastabend <john.fastabend@gmail.com>
Cc: KP Singh <kpsingh@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-07-01 11:06:04 -07:00
Kalesh Singh
3845f256a8 procfs/dmabuf: add inode number to /proc/*/fdinfo
And 'ino' field to /proc/<pid>/fdinfo/<FD> and
/proc/<pid>/task/<tid>/fdinfo/<FD>.

The inode numbers can be used to uniquely identify DMA buffers in user
space and avoids a dependency on /proc/<pid>/fd/* when accounting
per-process DMA buffer sizes.

Link: https://lkml.kernel.org/r/20210308170651.919148-2-kaleshsingh@google.com
Signed-off-by: Kalesh Singh <kaleshsingh@google.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Acked-by: Christian König <christian.koenig@amd.com>
Cc: Jann Horn <jannh@google.com>
Cc: Jeff Vander Stoep <jeffv@google.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Hridya Valsaraju <hridya@google.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Kalesh Singh <kaleshsingh@google.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Alexey Gladkov <gladkov.alexey@gmail.com>
Cc: Szabolcs Nagy <szabolcs.nagy@arm.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Christian Brauner <christian.brauner@ubuntu.com>
Cc: Michel Lespinasse <walken@google.com>
Cc: Bernd Edlinger <bernd.edlinger@hotmail.de>
Cc: Andrei Vagin <avagin@gmail.com>
Cc: Helge Deller <deller@gmx.de>
Cc: James Morris <jamorris@linux.microsoft.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-07-01 11:06:04 -07:00
Kalesh Singh
7bc3fa0172 procfs: allow reading fdinfo with PTRACE_MODE_READ
Android captures per-process system memory state when certain low memory
events (e.g a foreground app kill) occur, to identify potential memory
hoggers.  In order to measure how much memory a process actually consumes,
it is necessary to include the DMA buffer sizes for that process in the
memory accounting.  Since the handle to DMA buffers are raw FDs, it is
important to be able to identify which processes have FD references to a
DMA buffer.

Currently, DMA buffer FDs can be accounted using /proc/<pid>/fd/* and
/proc/<pid>/fdinfo -- both are only readable by the process owner, as
follows:

  1. Do a readlink on each FD.
  2. If the target path begins with "/dmabuf", then the FD is a dmabuf FD.
  3. stat the file to get the dmabuf inode number.
  4. Read/ proc/<pid>/fdinfo/<fd>, to get the DMA buffer size.

Accessing other processes' fdinfo requires root privileges.  This limits
the use of the interface to debugging environments and is not suitable for
production builds.  Granting root privileges even to a system process
increases the attack surface and is highly undesirable.

Since fdinfo doesn't permit reading process memory and manipulating
process state, allow accessing fdinfo under PTRACE_MODE_READ_FSCRED.

Link: https://lkml.kernel.org/r/20210308170651.919148-1-kaleshsingh@google.com
Signed-off-by: Kalesh Singh <kaleshsingh@google.com>
Suggested-by: Jann Horn <jannh@google.com>
Acked-by: Christian König <christian.koenig@amd.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Alexey Gladkov <gladkov.alexey@gmail.com>
Cc: Andrei Vagin <avagin@gmail.com>
Cc: Bernd Edlinger <bernd.edlinger@hotmail.de>
Cc: Christian Brauner <christian.brauner@ubuntu.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Hridya Valsaraju <hridya@google.com>
Cc: James Morris <jamorris@linux.microsoft.com>
Cc: Jeff Vander Stoep <jeffv@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kees Cook <keescook@chromium.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Michel Lespinasse <walken@google.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Szabolcs Nagy <szabolcs.nagy@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-07-01 11:06:04 -07:00
Marcelo Henrique Cerri
d238692b4b proc: Avoid mixing integer types in mem_rw()
Use size_t when capping the count argument received by mem_rw(). Since
count is size_t, using min_t(int, ...) can lead to a negative value
that will later be passed to access_remote_vm(), which can cause
unexpected behavior.

Since we are capping the value to at maximum PAGE_SIZE, the conversion
from size_t to int when passing it to access_remote_vm() as "len"
shouldn't be a problem.

Link: https://lkml.kernel.org/r/20210512125215.3348316-1-marcelo.cerri@canonical.com
Reviewed-by: David Disseldorp <ddiss@suse.de>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Signed-off-by: Marcelo Henrique Cerri <marcelo.cerri@canonical.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Souza Cascardo <cascardo@canonical.com>
Cc: Christian Brauner <christian.brauner@ubuntu.com>
Cc: Michel Lespinasse <walken@google.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-07-01 11:06:04 -07:00
Alistair Popple
8f187163eb nouveau/svm: implement atomic SVM access
Some NVIDIA GPUs do not support direct atomic access to system memory via
PCIe.  Instead this must be emulated by granting the GPU exclusive access
to the memory.  This is achieved by replacing CPU page table entries with
special swap entries that fault on userspace access.

The driver then grants the GPU permission to update the page undergoing
atomic access via the GPU page tables.  When CPU access to the page is
required a CPU fault is raised which calls into the device driver via MMU
notifiers to revoke the atomic access.  The original page table entries
are then restored allowing CPU access to proceed.

Link: https://lkml.kernel.org/r/20210616105937.23201-11-apopple@nvidia.com
Signed-off-by: Alistair Popple <apopple@nvidia.com>
Reviewed-by: Ben Skeggs <bskeggs@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-07-01 11:06:04 -07:00
Alistair Popple
f81c69a2a1 nouveau/svm: refactor nouveau_range_fault
Call mmu_interval_notifier_insert() as part of nouveau_range_fault().
This doesn't introduce any functional change but makes it easier for a
subsequent patch to alter the behaviour of nouveau_range_fault() to
support GPU atomic operations.

Link: https://lkml.kernel.org/r/20210616105937.23201-10-apopple@nvidia.com
Signed-off-by: Alistair Popple <apopple@nvidia.com>
Reviewed-by: Ben Skeggs <bskeggs@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-07-01 11:06:03 -07:00
Alistair Popple
b659baea75 mm: selftests for exclusive device memory
Adds some selftests for exclusive device memory.

Link: https://lkml.kernel.org/r/20210616105937.23201-9-apopple@nvidia.com
Signed-off-by: Alistair Popple <apopple@nvidia.com>
Acked-by: Jason Gunthorpe <jgg@nvidia.com>
Tested-by: Ralph Campbell <rcampbell@nvidia.com>
Reviewed-by: Ralph Campbell <rcampbell@nvidia.com>
Cc: Ben Skeggs <bskeggs@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Hugh Dickins <hughd@google.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Peter Xu <peterx@redhat.com>
Cc: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-07-01 11:06:03 -07:00
Alistair Popple
b756a3b5e7 mm: device exclusive memory access
Some devices require exclusive write access to shared virtual memory (SVM)
ranges to perform atomic operations on that memory.  This requires CPU
page tables to be updated to deny access whilst atomic operations are
occurring.

In order to do this introduce a new swap entry type
(SWP_DEVICE_EXCLUSIVE).  When a SVM range needs to be marked for exclusive
access by a device all page table mappings for the particular range are
replaced with device exclusive swap entries.  This causes any CPU access
to the page to result in a fault.

Faults are resovled by replacing the faulting entry with the original
mapping.  This results in MMU notifiers being called which a driver uses
to update access permissions such as revoking atomic access.  After
notifiers have been called the device will no longer have exclusive access
to the region.

Walking of the page tables to find the target pages is handled by
get_user_pages() rather than a direct page table walk.  A direct page
table walk similar to what migrate_vma_collect()/unmap() does could also
have been utilised.  However this resulted in more code similar in
functionality to what get_user_pages() provides as page faulting is
required to make the PTEs present and to break COW.

[dan.carpenter@oracle.com: fix signedness bug in make_device_exclusive_range()]
  Link: https://lkml.kernel.org/r/YNIz5NVnZ5GiZ3u1@mwanda

Link: https://lkml.kernel.org/r/20210616105937.23201-8-apopple@nvidia.com
Signed-off-by: Alistair Popple <apopple@nvidia.com>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Ben Skeggs <bskeggs@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-07-01 11:06:03 -07:00
Alistair Popple
9a5cc85c40 mm/memory.c: allow different return codes for copy_nonpresent_pte()
Currently if copy_nonpresent_pte() returns a non-zero value it is assumed
to be a swap entry which requires further processing outside the loop in
copy_pte_range() after dropping locks.  This prevents other values being
returned to signal conditions such as failure which a subsequent change
requires.

Instead make copy_nonpresent_pte() return an error code if further
processing is required and read the value for the swap entry in the main
loop under the ptl.

Link: https://lkml.kernel.org/r/20210616105937.23201-7-apopple@nvidia.com
Signed-off-by: Alistair Popple <apopple@nvidia.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Cc: Ben Skeggs <bskeggs@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-07-01 11:06:03 -07:00
Alistair Popple
6b49bf6ddb mm: rename migrate_pgmap_owner
MMU notifier ranges have a migrate_pgmap_owner field which is used by
drivers to store a pointer.  This is subsequently used by the driver
callback to filter MMU_NOTIFY_MIGRATE events.  Other notifier event types
can also benefit from this filtering, so rename the 'migrate_pgmap_owner'
field to 'owner' and create a new notifier initialisation function to
initialise this field.

Link: https://lkml.kernel.org/r/20210616105937.23201-6-apopple@nvidia.com
Signed-off-by: Alistair Popple <apopple@nvidia.com>
Suggested-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Cc: Ben Skeggs <bskeggs@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-07-01 11:06:03 -07:00
Alistair Popple
a98a2f0c8c mm/rmap: split migration into its own function
Migration is currently implemented as a mode of operation for
try_to_unmap_one() generally specified by passing the TTU_MIGRATION flag
or in the case of splitting a huge anonymous page TTU_SPLIT_FREEZE.

However it does not have much in common with the rest of the unmap
functionality of try_to_unmap_one() and thus splitting it into a separate
function reduces the complexity of try_to_unmap_one() making it more
readable.

Several simplifications can also be made in try_to_migrate_one() based on
the following observations:

 - All users of TTU_MIGRATION also set TTU_IGNORE_MLOCK.
 - No users of TTU_MIGRATION ever set TTU_IGNORE_HWPOISON.
 - No users of TTU_MIGRATION ever set TTU_BATCH_FLUSH.

TTU_SPLIT_FREEZE is a special case of migration used when splitting an
anonymous page.  This is most easily dealt with by calling the correct
function from unmap_page() in mm/huge_memory.c - either try_to_migrate()
for PageAnon or try_to_unmap().

Link: https://lkml.kernel.org/r/20210616105937.23201-5-apopple@nvidia.com
Signed-off-by: Alistair Popple <apopple@nvidia.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Ralph Campbell <rcampbell@nvidia.com>
Cc: Ben Skeggs <bskeggs@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Peter Xu <peterx@redhat.com>
Cc: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-07-01 11:06:03 -07:00