Pull dmaengine updates from Vinod Koul:
 "A fairly small dmaengine update which includes mostly driver updates
  (dmatest, dw-edma, ioat, mmp-tdma and k3-udma) along with Renesas
  binding update to json-schema"

* tag 'dmaengine-5.8-rc1' of git://git.infradead.org/users/vkoul/slave-dma: (39 commits)
  dmaengine: imx-sdma: initialize all script addresses
  dmaengine: ti: k3-udma: Use proper return code in alloc_chan_resources
  dmaengine: ti: k3-udma: Remove udma_chan.in_ring_cnt
  dmaengine: ti: k3-udma: Add missing dma_sync call for rx flush descriptor
  dmaengine: at_xdmac: Replace zero-length array with flexible-array
  dmaengine: at_hdmac: Replace zero-length array with flexible-array
  dmaengine: qcom: bam_dma: Replace zero-length array with flexible-array
  dmaengine: ti: k3-udma: Use PTR_ERR_OR_ZERO() to simplify code
  dmaengine: moxart-dma: Drop pointless static qualifier in moxart_probe()
  dmaengine: sf-pdma: Simplify the error handling path in 'sf_pdma_probe()'
  dmaengine: qcom_hidma: use true,false for bool variable
  dmaengine: dw-edma: support local dma device transfer semantics
  dmaengine: Fix doc strings to satisfy validation script
  dmaengine: Include dmaengine.h into dmaengine.c
  dmaengine: dmatest: Describe members of struct dmatest_info
  dmaengine: dmatest: Describe members of struct dmatest_params
  dmaengine: dmatest: Allow negative timeout value to specify infinite wait
  Revert "dmaengine: dmatest: timeout value of -1 should specify infinite wait"
  dmaengine: stm32-dma: direct mode support through device tree
  dt-bindings: dma: add direct mode support through device tree in stm32-dma
  ...

The improved paragraph about line lengths contains a sentence with a
duplicate word: there is one "are" at the end of a line, followed by a
second one at the beginning of the next line.

Drop the first one, as that one is part of the longest line.

Fixes: bdc48fa1 ("checkpatch/coding-style: deprecate 80-column warning")
Signed-off-by: NGeert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

"mm: consolidate pte_index() and pte_offset_*() definitions" was supposed
to remove arch/sparc/mm/srmmu.c:pte_offset_kernel().

Fixes: 974b9b2c ("mm: consolidate pte_index() and pte_offset_*() definitions")
Reported-by: Nkernel test robot <lkp@intel.com>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Pull fuse updates from Miklos Szeredi:

 - Fix a rare deadlock in virtiofs

 - Fix st_blocks in writeback cache mode

 - Fix wrong checks in splice move causing spurious warnings

 - Fix a race between a GETATTR request and a FUSE_NOTIFY_INVAL_INODE
   notification

 - Use rb-tree instead of linear search for pages currently under
   writeout by userspace

 - Fix copy_file_range() inconsistencies

* tag 'fuse-update-5.8' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse:
  fuse: copy_file_range should truncate cache
  fuse: fix copy_file_range cache issues
  fuse: optimize writepages search
  fuse: update attr_version counter on fuse_notify_inval_inode()
  fuse: don't check refcount after stealing page
  fuse: fix weird page warning
  fuse: use dump_page
  virtiofs: do not use fuse_fill_super_common() for device installation
  fuse: always allow query of st_dev
  fuse: always flush dirty data on close(2)
  fuse: invalidate inode attr in writeback cache mode
  fuse: Update stale comment in queue_interrupt()
  fuse: BUG_ON correction in fuse_dev_splice_write()
  virtiofs: Add mount option and atime behavior to the doc
  virtiofs: schedule blocking async replies in separate worker

Pull overlayfs updates from Miklos Szeredi:
 "Fixes:

   - Resolve mount option conflicts consistently

   - Sync before remount R/O

   - Fix file handle encoding corner cases

   - Fix metacopy related issues

   - Fix an unintialized return value

   - Add missing permission checks for underlying layers

  Optimizations:

   - Allow multipe whiteouts to share an inode

   - Optimize small writes by inheriting SB_NOSEC from upper layer

   - Do not call ->syncfs() multiple times for sync(2)

   - Do not cache negative lookups on upper layer

   - Make private internal mounts longterm"

* tag 'ovl-update-5.8' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs: (27 commits)
  ovl: remove unnecessary lock check
  ovl: make oip->index bool
  ovl: only pass ->ki_flags to ovl_iocb_to_rwf()
  ovl: make private mounts longterm
  ovl: get rid of redundant members in struct ovl_fs
  ovl: add accessor for ofs->upper_mnt
  ovl: initialize error in ovl_copy_xattr
  ovl: drop negative dentry in upper layer
  ovl: check permission to open real file
  ovl: call secutiry hook in ovl_real_ioctl()
  ovl: verify permissions in ovl_path_open()
  ovl: switch to mounter creds in readdir
  ovl: pass correct flags for opening real directory
  ovl: fix redirect traversal on metacopy dentries
  ovl: initialize OVL_UPPERDATA in ovl_lookup()
  ovl: use only uppermetacopy state in ovl_lookup()
  ovl: simplify setting of origin for index lookup
  ovl: fix out of bounds access warning in ovl_check_fb_len()
  ovl: return required buffer size for file handles
  ovl: sync dirty data when remounting to ro mode
  ...

Pull AFS fixes from David Howells:
 "A set of small patches to fix some things, most of them minor.

   - Fix a memory leak in afs_put_sysnames()

   - Fix an oops in AFS file locking

   - Fix new use of BUG()

   - Fix debugging statements containing %px

   - Remove afs_zero_fid as it's unused

   - Make afs_zap_data() static"

* tag 'afs-fixes-20200609' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs:
  afs: Make afs_zap_data() static
  afs: Remove afs_zero_fid as it's not used
  afs: Fix debugging statements with %px to be %p
  afs: Fix use of BUG()
  afs: Fix file locking
  afs: Fix memory leak in afs_put_sysnames()

Pull f2fs updates from Jaegeuk Kim:
 "In this round, we've added some knobs to enhance compression feature
  and harden testing environment. In addition, we've fixed several bugs
  reported from Android devices such as long discarding latency, device
  hanging during quota_sync, etc.

  Enhancements:
   - support lzo-rle algorithm
   - add two ioctls to release and reserve blocks for compression
   - support partial truncation/fiemap on compressed file
   - introduce sysfs entries to attach IO flags explicitly
   - add iostat trace point along with read io stat

  Bug fixes:
   - fix long discard latency
   - flush quota data by f2fs_quota_sync correctly
   - fix to recover parent inode number for power-cut recovery
   - fix lz4/zstd output buffer budget
   - parse checkpoint mount option correctly
   - avoid inifinite loop to wait for flushing node/meta pages
   - manage discard space correctly

  And some refactoring and clean up patches were added"

* tag 'f2fs-for-5.8' of git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs: (51 commits)
  f2fs: attach IO flags to the missing cases
  f2fs: add node_io_flag for bio flags likewise data_io_flag
  f2fs: remove unused parameter of f2fs_put_rpages_mapping()
  f2fs: handle readonly filesystem in f2fs_ioc_shutdown()
  f2fs: avoid utf8_strncasecmp() with unstable name
  f2fs: don't return vmalloc() memory from f2fs_kmalloc()
  f2fs: fix retry logic in f2fs_write_cache_pages()
  f2fs: fix wrong discard space
  f2fs: compress: don't compress any datas after cp stop
  f2fs: remove unneeded return value of __insert_discard_tree()
  f2fs: fix wrong value of tracepoint parameter
  f2fs: protect new segment allocation in expand_inode_data
  f2fs: code cleanup by removing ifdef macro surrounding
  f2fs: avoid inifinite loop to wait for flushing node pages at cp_error
  f2fs: flush dirty meta pages when flushing them
  f2fs: fix checkpoint=disable:%u%%
  f2fs: compress: fix zstd data corruption
  f2fs: add compressed/gc data read IO stat
  f2fs: fix potential use-after-free issue
  f2fs: compress: don't handle non-compressed data in workqueue
  ...

Pull exfat update from Namjae Jeon:
 "Bug fixes:
   - Fix memory leak on mount failure with iocharset= option
   - Fix incorrect update of stream entry
   - Fix cluster range validation error

  Clean-ups:
   - Remove unused code and unneeded assignment
   - Rename variables in exfat structure as specification
   - Reorganize boot sector analysis code
   - Simplify exfat_utf8_d_hash and exfat_utf8_d_cmp()
   - Optimize exfat entry cache functions
   - Improve wording of EXFAT_DEFAULT_IOCHARSET config option

 New Feature:
   - Add boot region verification"

* tag 'exfat-for-5.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/linkinjeon/exfat:
  exfat: Fix potential use after free in exfat_load_upcase_table()
  exfat: fix range validation error in alloc and free cluster
  exfat: fix incorrect update of stream entry in __exfat_truncate()
  exfat: fix memory leak in exfat_parse_param()
  exfat: remove unnecessary reassignment of p_uniname->name_len
  exfat: standardize checksum calculation
  exfat: add boot region verification
  exfat: separate the boot sector analysis
  exfat: redefine PBR as boot_sector
  exfat: optimize dir-cache
  exfat: replace 'time_ms' with 'time_cs'
  exfat: remove the assignment of 0 to bool variable
  exfat: Remove unused functions exfat_high_surrogate() and exfat_low_surrogate()
  exfat: Simplify exfat_utf8_d_hash() for code points above U+FFFF
  exfat: Improve wording of EXFAT_DEFAULT_IOCHARSET config option
  exfat: Use a more common logging style
  exfat: Simplify exfat_utf8_d_cmp() for code points above U+FFFF

__get_kernel_nofault() didn't have the parentheses around the use of
'src' and 'dst' macro arguments, making the casts potentially do the
wrong thing.

The parentheses aren't necessary with the current very limited use in
mm/access.c, but it's bad form, and future use-cases might have very
unexpected errors as a result.

Do the same for unsafe_copy_loop() while at it, although in that case it
is an entirely internal x86 uaccess helper macro that isn't used
anywhere else and any other use would be invalid anyway.

Fixes: fa94111d ("x86: use non-set_fs based maccess routines")
Cc: Christoph Hellwig <hch@lst.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Make afs_zap_data() static as it's only used in the file in which it is
defined.
Signed-off-by: NDavid Howells <dhowells@redhat.com>

Remove afs_zero_fid as it's not used.
Signed-off-by: NDavid Howells <dhowells@redhat.com>

Fix a couple of %px to be %p in debugging statements.

Fixes: e49c7b2f ("afs: Build an abstraction around an "operation" concept")
Fixes: 8a070a96 ("afs: Detect cell aliases 1 - Cells with root volumes")
Reported-by: NKees Cook <keescook@chromium.org>
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Reviewed-by: NKees Cook <keescook@chromium.org>

Pull tracing updates from Steven Rostedt:
 "No new features this release. Mostly clean ups, restructuring and
  documentation.

   - Have ftrace_bug() show ftrace errors before the WARN, as the WARN
     will reboot the box before the error messages are printed if
     panic_on_warn is set.

   - Have traceoff_on_warn disable tracing sooner (before prints)

   - Write a message to the trace buffer that its being disabled when
     disable_trace_on_warning() is set.

   - Separate out synthetic events from histogram code to let it be used
     by other parts of the kernel.

   - More documentation on histogram design.

   - Other small fixes and clean ups"

* tag 'trace-v5.8' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  tracing: Remove obsolete PREEMPTIRQ_EVENTS kconfig option
  tracing/doc: Fix ascii-art in histogram-design.rst
  tracing: Add a trace print when traceoff_on_warning is triggered
  ftrace,bug: Improve traceoff_on_warn
  selftests/ftrace: Distinguish between hist and synthetic event checks
  tracing: Move synthetic events to a separate file
  tracing: Fix events.rst section numbering
  tracing/doc: Fix typos in histogram-design.rst
  tracing: Add hist_debug trace event files for histogram debugging
  tracing: Add histogram-design document
  tracing: Check state.disabled in synth event trace functions
  tracing/probe: reverse arguments to list_add
  tools/bootconfig: Add a summary of test cases and return error
  ftrace: show debugging information when panic_on_warn set

Merge tag 'linux-kselftest-kunit-5.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest

Pull Kunit updates from Shuah Khan:
 "This consists of:

   - Several config fragment fixes from Anders Roxell to improve test
     coverage.

   - Improvements to kunit run script to use defconfig as default and
     restructure the code for config/build/exec/parse from Vitor Massaru
     Iha and David Gow.

   - Miscellaneous documentation warn fix"

* tag 'linux-kselftest-kunit-5.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest:
  security: apparmor: default KUNIT_* fragments to KUNIT_ALL_TESTS
  fs: ext4: default KUNIT_* fragments to KUNIT_ALL_TESTS
  drivers: base: default KUNIT_* fragments to KUNIT_ALL_TESTS
  lib: Kconfig.debug: default KUNIT_* fragments to KUNIT_ALL_TESTS
  kunit: default KUNIT_* fragments to KUNIT_ALL_TESTS
  kunit: Kconfig: enable a KUNIT_ALL_TESTS fragment
  kunit: Fix TabError, remove defconfig code and handle when there is no kunitconfig
  kunit: use KUnit defconfig by default
  kunit: use --build_dir=.kunit as default
  Documentation: test.h - fix warnings
  kunit: kunit_tool: Separate out config/build/exec/parse

Merge tag 'linux-kselftest-5.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest

Pull kselftest updates from Shuah Khan:
 "This consists of:

   - Several fixes from Masami Hiramatsu to improve coverage for lib and
     sysctl tests.

   - Clean up to vdso test and a new test for getcpu() from Mark Brown.

   - Add new gen_tar selftests Makefile target generate selftest package
     running "make gen_tar" in selftests directory from Veronika
     Kabatova.

   - Other miscellaneous fixes to timens, exec, tpm2 tests"

* tag 'linux-kselftest-5.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest:
  selftests/sysctl: Make sysctl test driver as a module
  selftests/sysctl: Fix to load test_sysctl module
  lib: Make test_sysctl initialized as module
  lib: Make prime number generator independently selectable
  selftests/ftrace: Return unsupported if no error_log file
  selftests/ftrace: Use printf for backslash included command
  selftests/timens: handle a case when alarm clocks are not supported
  Kernel selftests: Add check if TPM devices are supported
  selftests: vdso: Add a selftest for vDSO getcpu()
  selftests: vdso: Use a header file to prototype parse_vdso API
  selftests: vdso: Rename vdso_test to vdso_test_gettimeofday
  selftests/exec: Verify execve of non-regular files fail
  selftests: introduce gen_tar Makefile target

Merge even more updates from Andrew Morton:

 - a kernel-wide sweep of show_stack()

 - pagetable cleanups

 - abstract out accesses to mmap_sem - prep for mmap_sem scalability work

 - hch's user acess work

Subsystems affected by this patch series: debug, mm/pagemap, mm/maccess,
mm/documentation.

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (93 commits)
  include/linux/cache.h: expand documentation over __read_mostly
  maccess: return -ERANGE when probe_kernel_read() fails
  x86: use non-set_fs based maccess routines
  maccess: allow architectures to provide kernel probing directly
  maccess: move user access routines together
  maccess: always use strict semantics for probe_kernel_read
  maccess: remove strncpy_from_unsafe
  tracing/kprobes: handle mixed kernel/userspace probes better
  bpf: rework the compat kernel probe handling
  bpf:bpf_seq_printf(): handle potentially unsafe format string better
  bpf: handle the compat string in bpf_trace_copy_string better
  bpf: factor out a bpf_trace_copy_string helper
  maccess: unify the probe kernel arch hooks
  maccess: remove probe_read_common and probe_write_common
  maccess: rename strnlen_unsafe_user to strnlen_user_nofault
  maccess: rename strncpy_from_unsafe_strict to strncpy_from_kernel_nofault
  maccess: rename strncpy_from_unsafe_user to strncpy_from_user_nofault
  maccess: update the top of file comment
  maccess: clarify kerneldoc comments
  maccess: remove duplicate kerneldoc comments
  ...

uprobe_write_opcode() must not cross page boundary; prepare_uprobe()
relies on arch_uprobe_analyze_insn() which should validate "vaddr" but
some architectures (csky, s390, and sparc) don't do this.

We can remove the BUG_ON() check in prepare_uprobe() and validate the
offset early in __uprobe_register(). The new IS_ALIGNED() check matches
the alignment check in arch_prepare_kprobe() on supported architectures,
so I think that all insns must be aligned to UPROBE_SWBP_INSN_SIZE.

Another problem is __update_ref_ctr() which was wrong from the very
beginning, it can read/write outside of kmap'ed page unless "vaddr" is
aligned to sizeof(short), __uprobe_register() should check this too.
Reported-by: NLinus Torvalds <torvalds@linux-foundation.org>
Suggested-by: NLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: NOleg Nesterov <oleg@redhat.com>
Reviewed-by: NSrikar Dronamraju <srikar@linux.vnet.ibm.com>
Acked-by: NChristian Borntraeger <borntraeger@de.ibm.com>
Tested-by: NSven Schnelle <svens@linux.ibm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: stable@vger.kernel.org
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

__read_mostly can easily be misused by folks, its not meant for just
read-only data.  There are performance reasons for using it, but we also
don't provide any guidance about its use.  Provide a bit more guidance
over its use.
Signed-off-by: NLuis Chamberlain <mcgrof@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Reviewed-by: NKees Cook <keescook@chromium.org>
Acked-by: NChristoph Lameter <cl@linux.com>
Acked-by: NRafael Aquini <aquini@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Matthew Wilcox <willy@infradead.org>
Link: http://lkml.kernel.org/r/20200507161424.2584-1-mcgrof@kernel.orgSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Allow the callers to distinguish a real unmapped address vs a range
that can't be probed.
Suggested-by: NMasami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Reviewed-by: NMasami Hiramatsu <mhiramat@kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20200521152301.2587579-24-hch@lst.deSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Provide arch_kernel_read and arch_kernel_write routines to implement the
maccess routines without messing with set_fs and without stac/clac that
opens up access to user space.

[akpm@linux-foundation.org: coding style fixes]
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20200521152301.2587579-20-hch@lst.deSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Provide alternative versions of probe_kernel_read, probe_kernel_write
and strncpy_from_kernel_unsafe that don't need set_fs magic, but instead
use arch hooks that are modelled after unsafe_{get,put}_user to access
kernel memory in an exception safe way.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20200521152301.2587579-19-hch@lst.deSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Move kernel access vs user access routines together to ease upcoming
ifdefs.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20200521152301.2587579-18-hch@lst.deSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Except for historical confusion in the kprobes/uprobes and bpf tracers,
which has been fixed now, there is no good reason to ever allow user
memory accesses from probe_kernel_read.  Switch probe_kernel_read to only
read from kernel memory.

[akpm@linux-foundation.org: update it for "mm, dump_page(): do not crash with invalid mapping pointer"]
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20200521152301.2587579-17-hch@lst.deSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

All users are gone now.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20200521152301.2587579-16-hch@lst.deSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Instead of using the dangerous probe_kernel_read and strncpy_from_unsafe
helpers, rework probes to try a user probe based on the address if the
architecture has a common address space for kernel and userspace.

[svens@linux.ibm.com:use strncpy_from_kernel_nofault() in fetch_store_string()]
  Link: http://lkml.kernel.org/r/20200606181903.49384-1-svens@linux.ibm.comSigned-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NSven Schnelle <svens@linux.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20200521152301.2587579-15-hch@lst.deSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Instead of using the dangerous probe_kernel_read and strncpy_from_unsafe
helpers, rework the compat probes to check if an address is a kernel or
userspace one, and then use the low-level kernel or user probe helper
shared by the proper kernel and user probe helpers.  This slightly
changes behavior as the compat probe on a user address doesn't check
the lockdown flags, just as the pure user probes do.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20200521152301.2587579-14-hch@lst.deSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

User the proper helper for kernel or userspace addresses based on
TASK_SIZE instead of the dangerous strncpy_from_unsafe function.
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

User the proper helper for kernel or userspace addresses based on
TASK_SIZE instead of the dangerous strncpy_from_unsafe function.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20200521152301.2587579-13-hch@lst.deSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Split out a helper to do the fault free access to the string pointer
to get it out of a crazy indentation level.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20200521152301.2587579-12-hch@lst.deSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Currently architectures have to override every routine that probes
kernel memory, which includes a pure read and strcpy, both in strict
and not strict variants.  Just provide a single arch hooks instead to
make sure all architectures cover all the cases.

[akpm@linux-foundation.org: fix !CONFIG_X86_64 build]
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20200521152301.2587579-11-hch@lst.deSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Each of the helpers has just two callers, which also different in
dealing with kernel or userspace pointers.  Just open code the logic
in the callers.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20200521152301.2587579-10-hch@lst.deSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This matches the naming of strnlen_user, and also makes it more clear
what the function is supposed to do.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20200521152301.2587579-9-hch@lst.deSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This matches the naming of strncpy_from_user_nofault, and also makes it
more clear what the function is supposed to do.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20200521152301.2587579-8-hch@lst.deSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This matches the naming of strncpy_from_user, and also makes it more
clear what the function is supposed to do.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20200521152301.2587579-7-hch@lst.deSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This file now also contains several helpers for accessing user memory.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20200521152301.2587579-6-hch@lst.deSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Add proper kerneldoc comments for probe_kernel_read_strict and
probe_kernel_read strncpy_from_unsafe_strict and explain the different
versus the non-strict version.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20200521152301.2587579-5-hch@lst.deSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Many of the maccess routines have a copy of the kerneldoc comment
in the header.  Remove it as it is not useful and will get out of
sync sooner or later.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20200521152301.2587579-4-hch@lst.deSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

maccess tends to define lots of underscore prefixed symbols that then
have other weak aliases.  But except for two cases they are never
actually used, so remove them.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20200521152301.2587579-3-hch@lst.deSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Patch series "clean up and streamline probe_kernel_* and friends", v4.

This series start cleaning up the safe kernel and user memory probing
helpers in mm/maccess.c, and then allows architectures to implement the
kernel probing without overriding the address space limit and temporarily
allowing access to user memory.  It then switches x86 over to this new
mechanism by reusing the unsafe_* uaccess logic.

This version also switches to the saner copy_{from,to}_kernel_nofault
naming suggested by Linus.

I kept the x86 helpers as-is without calling unsage_{get,put}_user as that
avoids a number of hard to trace casts, and it will still work with the
asm-goto based version easily.

This patch (of 20):

probe_kernel_write() is not used by any modular code.

[sfr@canb.auug.org.au: turns out that probe_user_write is used in modular code]
  Link: http://lkml.kernel.org/r/20200602195741.4faaa348@canb.auug.org.auSigned-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NStephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20200521152301.2587579-1-hch@lst.de
Link: http://lkml.kernel.org/r/20200521152301.2587579-2-hch@lst.deSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Convert comments that reference mmap_sem to reference mmap_lock instead.

[akpm@linux-foundation.org: fix up linux-next leftovers]
[akpm@linux-foundation.org: s/lockaphore/lock/, per Vlastimil]
[akpm@linux-foundation.org: more linux-next fixups, per Michel]
Signed-off-by: NMichel Lespinasse <walken@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Reviewed-by: NVlastimil Babka <vbabka@suse.cz>
Reviewed-by: NDaniel Jordan <daniel.m.jordan@oracle.com>
Cc: Davidlohr Bueso <dbueso@suse.de>
Cc: David Rientjes <rientjes@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Laurent Dufour <ldufour@linux.ibm.com>
Cc: Liam Howlett <Liam.Howlett@oracle.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ying Han <yinghan@google.com>
Link: http://lkml.kernel.org/r/20200520052908.204642-13-walken@google.comSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>