Commit Graph

2383 Commits

Author SHA1 Message Date
Gustavo A. R. Silva df561f6688 treewide: Use fallthrough pseudo-keyword
Replace the existing /* fall through */ comments and its variants with
the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary
fall-through markings when it is the case.

[1] https://www.kernel.org/doc/html/v5.7/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through

Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
2020-08-23 17:36:59 -05:00
Mike Rapoport 6f6aea7e96 parisc: fix PMD pages allocation by restoring pmd_alloc_one()
Commit 1355c31eeb ("asm-generic: pgalloc: provide generic pmd_alloc_one()
and pmd_free_one()") converted parisc to use generic version of
pmd_alloc_one() but it missed the fact that parisc uses order-1 pages for
PMD.

Restore the original version of pmd_alloc_one() for parisc, just use
GFP_PGTABLE_KERNEL that implies __GFP_ZERO instead of GFP_KERNEL and
memset.

Fixes: 1355c31eeb ("asm-generic: pgalloc: provide generic pmd_alloc_one() and pmd_free_one()")
Reported-by: Meelis Roos <mroos@linux.ee>
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Tested-by: Meelis Roos <mroos@linux.ee>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Link: https://lkml.kernel.org/r/9f2b5ebd-e4a4-0fa1-6cd3-4b9f6892d1ad@linux.ee
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-16 10:53:13 -07:00
Krzysztof Kozlowski 8f28ca6bd8 iomap: constify ioreadX() iomem argument (as in generic implementation)
Patch series "iomap: Constify ioreadX() iomem argument", v3.

The ioread8/16/32() and others have inconsistent interface among the
architectures: some taking address as const, some not.

It seems there is nothing really stopping all of them to take pointer to
const.

This patch (of 4):

The ioreadX() and ioreadX_rep() helpers have inconsistent interface.  On
some architectures void *__iomem address argument is a pointer to const,
on some not.

Implementations of ioreadX() do not modify the memory under the address so
they can be converted to a "const" version for const-safety and
consistency among architectures.

[krzk@kernel.org: sh: clk: fix assignment from incompatible pointer type for ioreadX()]
  Link: http://lkml.kernel.org/r/20200723082017.24053-1-krzk@kernel.org
[akpm@linux-foundation.org: fix drivers/mailbox/bcm-pdc-mailbox.c]
  Link: http://lkml.kernel.org/r/202007132209.Rxmv4QyS%25lkp@intel.com

Suggested-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Matt Turner <mattst88@gmail.com>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Rich Felker <dalias@libc.org>
Cc: Kalle Valo <kvalo@codeaurora.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: Jon Mason <jdmason@kudzu.us>
Cc: Allen Hubbe <allenbh@gmail.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Jason Wang <jasowang@redhat.com>
Link: http://lkml.kernel.org/r/20200709072837.5869-1-krzk@kernel.org
Link: http://lkml.kernel.org/r/20200709072837.5869-2-krzk@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-14 19:56:57 -07:00
Xiaoming Ni 88db0aa242 all arch: remove system call sys_sysctl
Since commit 61a47c1ad3 ("sysctl: Remove the sysctl system call"),
sys_sysctl is actually unavailable: any input can only return an error.

We have been warning about people using the sysctl system call for years
and believe there are no more users.  Even if there are users of this
interface if they have not complained or fixed their code by now they
probably are not going to, so there is no point in warning them any
longer.

So completely remove sys_sysctl on all architectures.

[nixiaoming@huawei.com: s390: fix build error for sys_call_table_emu]
 Link: http://lkml.kernel.org/r/20200618141426.16884-1-nixiaoming@huawei.com

Signed-off-by: Xiaoming Ni <nixiaoming@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Will Deacon <will@kernel.org>		[arm/arm64]
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Aleksa Sarai <cyphar@cyphar.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Bin Meng <bin.meng@windriver.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: chenzefeng <chenzefeng2@huawei.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Christian Brauner <christian@brauner.io>
Cc: Chris Zankel <chris@zankel.net>
Cc: David Howells <dhowells@redhat.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Diego Elio Pettenò <flameeyes@flameeyes.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Dominik Brodowski <linux@dominikbrodowski.net>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Helge Deller <deller@gmx.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Iurii Zaikin <yzaikin@google.com>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kars de Jong <jongk@linux-m68k.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Krzysztof Kozlowski <krzk@kernel.org>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: Marco Elver <elver@google.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Martin K. Petersen <martin.petersen@oracle.com>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Miklos Szeredi <mszeredi@redhat.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Cc: Nick Piggin <npiggin@gmail.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Olof Johansson <olof@lixom.net>
Cc: Paul Burton <paulburton@kernel.org>
Cc: "Paul E. McKenney" <paulmck@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Rich Felker <dalias@libc.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Sami Tolvanen <samitolvanen@google.com>
Cc: Sargun Dhillon <sargun@sargun.me>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Sudeep Holla <sudeep.holla@arm.com>
Cc: Sven Schnelle <svens@stackframe.org>
Cc: Thiago Jung Bauermann <bauerman@linux.ibm.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Zhou Yanjie <zhouyanjie@wanyeetech.com>
Link: http://lkml.kernel.org/r/20200616030734.87257-1-nixiaoming@huawei.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-14 19:56:56 -07:00
Linus Torvalds 7a02c8d45b Merge branch 'parisc-5.9-2' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux
Pull more parisc updates from Helge Deller:

 - Oscar Carter contributed a patch which fixes parisc's usage of
   dereference_function_descriptor() and thus will allow using the
   -Wcast-function-type compiler option in the top-level Makefile

 - Sven Schnelle fixed a bug in the SBA code to prevent crashes during
   kexec

 - John David Anglin provided implementations for __smp_store_release()
   and __smp_load_acquire barriers() which avoids using the sync
   assembler instruction and thus speeds up barrier paths

 - Some whitespace cleanups in parisc's atomic.h header file

* 'parisc-5.9-2' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux:
  parisc: Implement __smp_store_release and __smp_load_acquire barriers
  parisc: mask out enable and reserved bits from sba imask
  parisc: Whitespace cleanups in atomic.h
  parisc/kernel/ftrace: Remove function callback casts
  sections.h: dereference_function_descriptor() returns void pointer
2020-08-12 12:41:15 -07:00
Peter Xu af8a792627 mm/parisc: use general page fault accounting
Use the general page fault accounting by passing regs into
handle_mm_fault().  It naturally solve the issue of multiple page fault
accounting when page fault retry happened.

Add the missing PERF_COUNT_SW_PAGE_FAULTS perf events too.  Note, the
other two perf events (PERF_COUNT_SW_PAGE_FAULTS_[MAJ|MIN]) were done in
handle_mm_fault().

Signed-off-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: James E.J. Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Helge Deller <deller@gmx.de>
Link: http://lkml.kernel.org/r/20200707225021.200906-16-peterx@redhat.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-12 10:58:03 -07:00
Peter Xu bce617edec mm: do page fault accounting in handle_mm_fault
Patch series "mm: Page fault accounting cleanups", v5.

This is v5 of the pf accounting cleanup series.  It originates from Gerald
Schaefer's report on an issue a week ago regarding to incorrect page fault
accountings for retried page fault after commit 4064b98270 ("mm: allow
VM_FAULT_RETRY for multiple times"):

  https://lore.kernel.org/lkml/20200610174811.44b94525@thinkpad/

What this series did:

  - Correct page fault accounting: we do accounting for a page fault
    (no matter whether it's from #PF handling, or gup, or anything else)
    only with the one that completed the fault.  For example, page fault
    retries should not be counted in page fault counters.  Same to the
    perf events.

  - Unify definition of PERF_COUNT_SW_PAGE_FAULTS: currently this perf
    event is used in an adhoc way across different archs.

    Case (1): for many archs it's done at the entry of a page fault
    handler, so that it will also cover e.g.  errornous faults.

    Case (2): for some other archs, it is only accounted when the page
    fault is resolved successfully.

    Case (3): there're still quite some archs that have not enabled
    this perf event.

    Since this series will touch merely all the archs, we unify this
    perf event to always follow case (1), which is the one that makes most
    sense.  And since we moved the accounting into handle_mm_fault, the
    other two MAJ/MIN perf events are well taken care of naturally.

  - Unify definition of "major faults": the definition of "major
    fault" is slightly changed when used in accounting (not
    VM_FAULT_MAJOR).  More information in patch 1.

  - Always account the page fault onto the one that triggered the page
    fault.  This does not matter much for #PF handlings, but mostly for
    gup.  More information on this in patch 25.

Patchset layout:

Patch 1:     Introduced the accounting in handle_mm_fault(), not enabled.
Patch 2-23:  Enable the new accounting for arch #PF handlers one by one.
Patch 24:    Enable the new accounting for the rest outliers (gup, iommu, etc.)
Patch 25:    Cleanup GUP task_struct pointer since it's not needed any more

This patch (of 25):

This is a preparation patch to move page fault accountings into the
general code in handle_mm_fault().  This includes both the per task
flt_maj/flt_min counters, and the major/minor page fault perf events.  To
do this, the pt_regs pointer is passed into handle_mm_fault().

PERF_COUNT_SW_PAGE_FAULTS should still be kept in per-arch page fault
handlers.

So far, all the pt_regs pointer that passed into handle_mm_fault() is
NULL, which means this patch should have no intented functional change.

Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Cain <bcain@codeaurora.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Cc: Greentime Hu <green.hu@gmail.com>
Cc: Guo Ren <guoren@kernel.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Helge Deller <deller@gmx.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: James E.J. Bottomley <James.Bottomley@HansenPartnership.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Ley Foon Tan <ley.foon.tan@intel.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Nick Hu <nickhu@andestech.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Rich Felker <dalias@libc.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vincent Chen <deanbo422@gmail.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Link: http://lkml.kernel.org/r/20200707225021.200906-1-peterx@redhat.com
Link: http://lkml.kernel.org/r/20200707225021.200906-2-peterx@redhat.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-12 10:58:02 -07:00
Christoph Hellwig 428e2976a5 uaccess: remove segment_eq
segment_eq is only used to implement uaccess_kernel.  Just open code
uaccess_kernel in the arch uaccess headers and remove one layer of
indirection.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Acked-by: Greentime Hu <green.hu@gmail.com>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Nick Hu <nickhu@andestech.com>
Cc: Vincent Chen <deanbo422@gmail.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Link: http://lkml.kernel.org/r/20200710135706.537715-5-hch@lst.de
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-12 10:57:58 -07:00
John David Anglin e96ebd589d parisc: Implement __smp_store_release and __smp_load_acquire barriers
This patch implements the __smp_store_release and __smp_load_acquire barriers
using ordered stores and loads.  This avoids the sync instruction present in
the generic implementation.

Cc: <stable@vger.kernel.org> # 4.14+
Signed-off-by: Dave Anglin <dave.anglin@bell.net>
Signed-off-by: Helge Deller <deller@gmx.de>
2020-08-12 15:13:42 +02:00
Helge Deller 3bc6e3dc5a parisc: Whitespace cleanups in atomic.h
Fix whitespace indenting and drop trailing backslashes.

Cc: <stable@vger.kernel.org> # 4.19+
Signed-off-by: Helge Deller <deller@gmx.de>
2020-08-11 18:07:34 +02:00
Oscar Carter 875102ea4b parisc/kernel/ftrace: Remove function callback casts
In an effort to enable -Wcast-function-type in the top-level Makefile to
support Control Flow Integrity builds, remove all the function callback
casts.

Co-developed-by: Helge Deller <deller@gmx.de>
Signed-off-by: Oscar Carter <oscar.carter@gmx.com>
Signed-off-by: Helge Deller <deller@gmx.de>
2020-08-11 12:06:39 +02:00
Linus Torvalds 97d052ea3f A set of locking fixes and updates:
- Untangle the header spaghetti which causes build failures in various
     situations caused by the lockdep additions to seqcount to validate that
     the write side critical sections are non-preemptible.
 
   - The seqcount associated lock debug addons which were blocked by the
     above fallout.
 
     seqcount writers contrary to seqlock writers must be externally
     serialized, which usually happens via locking - except for strict per
     CPU seqcounts. As the lock is not part of the seqcount, lockdep cannot
     validate that the lock is held.
 
     This new debug mechanism adds the concept of associated locks.
     sequence count has now lock type variants and corresponding
     initializers which take a pointer to the associated lock used for
     writer serialization. If lockdep is enabled the pointer is stored and
     write_seqcount_begin() has a lockdep assertion to validate that the
     lock is held.
 
     Aside of the type and the initializer no other code changes are
     required at the seqcount usage sites. The rest of the seqcount API is
     unchanged and determines the type at compile time with the help of
     _Generic which is possible now that the minimal GCC version has been
     moved up.
 
     Adding this lockdep coverage unearthed a handful of seqcount bugs which
     have been addressed already independent of this.
 
     While generaly useful this comes with a Trojan Horse twist: On RT
     kernels the write side critical section can become preemtible if the
     writers are serialized by an associated lock, which leads to the well
     known reader preempts writer livelock. RT prevents this by storing the
     associated lock pointer independent of lockdep in the seqcount and
     changing the reader side to block on the lock when a reader detects
     that a writer is in the write side critical section.
 
  - Conversion of seqcount usage sites to associated types and initializers.
 -----BEGIN PGP SIGNATURE-----
 
 iQJHBAABCgAxFiEEQp8+kY+LLUocC4bMphj1TA10mKEFAl8xmPYTHHRnbHhAbGlu
 dXRyb25peC5kZQAKCRCmGPVMDXSYoTuQEACyzQCjU8PgehPp9oMqWzaX2fcVyuZO
 QU2yw6gmz2oTz3ZHUNwdW8UnzGh2OWosK3kDruoD9FtSS51lER1/ISfSPCGfyqxC
 KTjOcB1Kvxwq/3LcCx7Zi3ZxWApat74qs3EhYhKtEiQ2Y9xv9rLq8VV1UWAwyxq0
 eHpjlIJ6b6rbt+ARslaB7drnccOsdK+W/roNj4kfyt+gezjBfojGRdMGQNMFcpnv
 shuTC+vYurAVIiVA/0IuizgHfwZiXOtVpjVoEWaxg6bBH6HNuYMYzdSa/YrlDkZs
 n/aBI/Xkvx+Eacu8b1Zwmbzs5EnikUK/2dMqbzXKUZK61eV4hX5c2xrnr1yGWKTs
 F/juh69Squ7X6VZyKVgJ9RIccVueqwR2EprXWgH3+RMice5kjnXH4zURp0GHALxa
 DFPfB6fawcH3Ps87kcRFvjgm6FBo0hJ1AxmsW1dY4ACFB9azFa2euW+AARDzHOy2
 VRsUdhL9CGwtPjXcZ/9Rhej6fZLGBXKr8uq5QiMuvttp4b6+j9FEfBgD4S6h8csl
 AT2c2I9LcbWqyUM9P4S7zY/YgOZw88vHRuDH7tEBdIeoiHfrbSBU7EQ9jlAKq/59
 f+Htu2Io281c005g7DEeuCYvpzSYnJnAitj5Lmp/kzk2Wn3utY1uIAVszqwf95Ul
 81ppn2KlvzUK8g==
 =7Gj+
 -----END PGP SIGNATURE-----

Merge tag 'locking-urgent-2020-08-10' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull locking updates from Thomas Gleixner:
 "A set of locking fixes and updates:

   - Untangle the header spaghetti which causes build failures in
     various situations caused by the lockdep additions to seqcount to
     validate that the write side critical sections are non-preemptible.

   - The seqcount associated lock debug addons which were blocked by the
     above fallout.

     seqcount writers contrary to seqlock writers must be externally
     serialized, which usually happens via locking - except for strict
     per CPU seqcounts. As the lock is not part of the seqcount, lockdep
     cannot validate that the lock is held.

     This new debug mechanism adds the concept of associated locks.
     sequence count has now lock type variants and corresponding
     initializers which take a pointer to the associated lock used for
     writer serialization. If lockdep is enabled the pointer is stored
     and write_seqcount_begin() has a lockdep assertion to validate that
     the lock is held.

     Aside of the type and the initializer no other code changes are
     required at the seqcount usage sites. The rest of the seqcount API
     is unchanged and determines the type at compile time with the help
     of _Generic which is possible now that the minimal GCC version has
     been moved up.

     Adding this lockdep coverage unearthed a handful of seqcount bugs
     which have been addressed already independent of this.

     While generally useful this comes with a Trojan Horse twist: On RT
     kernels the write side critical section can become preemtible if
     the writers are serialized by an associated lock, which leads to
     the well known reader preempts writer livelock. RT prevents this by
     storing the associated lock pointer independent of lockdep in the
     seqcount and changing the reader side to block on the lock when a
     reader detects that a writer is in the write side critical section.

   - Conversion of seqcount usage sites to associated types and
     initializers"

* tag 'locking-urgent-2020-08-10' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (25 commits)
  locking/seqlock, headers: Untangle the spaghetti monster
  locking, arch/ia64: Reduce <asm/smp.h> header dependencies by moving XTP bits into the new <asm/xtp.h> header
  x86/headers: Remove APIC headers from <asm/smp.h>
  seqcount: More consistent seqprop names
  seqcount: Compress SEQCNT_LOCKNAME_ZERO()
  seqlock: Fold seqcount_LOCKNAME_init() definition
  seqlock: Fold seqcount_LOCKNAME_t definition
  seqlock: s/__SEQ_LOCKDEP/__SEQ_LOCK/g
  hrtimer: Use sequence counter with associated raw spinlock
  kvm/eventfd: Use sequence counter with associated spinlock
  userfaultfd: Use sequence counter with associated spinlock
  NFSv4: Use sequence counter with associated spinlock
  iocost: Use sequence counter with associated spinlock
  raid5: Use sequence counter with associated spinlock
  vfs: Use sequence counter with associated spinlock
  timekeeping: Use sequence counter with associated raw spinlock
  xfrm: policy: Use sequence counters with associated lock
  netfilter: nft_set_rbtree: Use sequence counter with associated rwlock
  netfilter: conntrack: Use sequence counter with associated spinlock
  sched: tasks: Use sequence counter with associated spinlock
  ...
2020-08-10 19:07:44 -07:00
Linus Torvalds 8d3e09b433 Merge branch 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull regset conversion fix from Al Viro:
 "Fix a regression from an unnoticed bisect hazard in the regset series.

  A bunch of old (aout, originally) primitives used by coredumps became
  dead code after fdpic conversion to regsets. Removal of that dead code
  had been the first commit in the followups to regset series;
  unfortunately, it happened to hide the bisect hazard on sh (extern for
  fpregs_get() had not been updated in the main series when it should
  have been; followup simply made fpregs_get() static). And without that
  followup commit this bisect hazard became breakage in the mainline"

Tested-by: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>

* 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  kill unused dump_fpu() instances
2020-08-09 13:33:54 -07:00
Linus Torvalds 81e11336d9 Merge branch 'akpm' (patches from Andrew)
Merge misc updates from Andrew Morton:

 - a few MM hotfixes

 - kthread, tools, scripts, ntfs and ocfs2

 - some of MM

Subsystems affected by this patch series: kthread, tools, scripts, ntfs,
ocfs2 and mm (hofixes, pagealloc, slab-generic, slab, slub, kcsan,
debug, pagecache, gup, swap, shmem, memcg, pagemap, mremap, mincore,
sparsemem, vmalloc, kasan, pagealloc, hugetlb and vmscan).

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (162 commits)
  mm: vmscan: consistent update to pgrefill
  mm/vmscan.c: fix typo
  khugepaged: khugepaged_test_exit() check mmget_still_valid()
  khugepaged: retract_page_tables() remember to test exit
  khugepaged: collapse_pte_mapped_thp() protect the pmd lock
  khugepaged: collapse_pte_mapped_thp() flush the right range
  mm/hugetlb: fix calculation of adjust_range_if_pmd_sharing_possible
  mm: thp: replace HTTP links with HTTPS ones
  mm/page_alloc: fix memalloc_nocma_{save/restore} APIs
  mm/page_alloc.c: skip setting nodemask when we are in interrupt
  mm/page_alloc: fallbacks at most has 3 elements
  mm/page_alloc: silence a KASAN false positive
  mm/page_alloc.c: remove unnecessary end_bitidx for [set|get]_pfnblock_flags_mask()
  mm/page_alloc.c: simplify pageblock bitmap access
  mm/page_alloc.c: extract the common part in pfn_to_bitidx()
  mm/page_alloc.c: replace the definition of NR_MIGRATETYPE_BITS with PB_migratetype_bits
  mm/shuffle: remove dynamic reconfiguration
  mm/memory_hotplug: document why shuffle_zone() is relevant
  mm/page_alloc: remove nr_free_pagecache_pages()
  mm: remove vm_total_pages
  ...
2020-08-07 11:39:33 -07:00
Mike Rapoport c89ab04feb mm/sparse: cleanup the code surrounding memory_present()
After removal of CONFIG_HAVE_MEMBLOCK_NODE_MAP we have two equivalent
functions that call memory_present() for each region in memblock.memory:
sparse_memory_present_with_active_regions() and membocks_present().

Moreover, all architectures have a call to either of these functions
preceding the call to sparse_init() and in the most cases they are called
one after the other.

Mark the regions from memblock.memory as present during sparce_init() by
making sparse_init() call memblocks_present(), make memblocks_present()
and memory_present() functions static and remove redundant
sparse_memory_present_with_active_regions() function.

Also remove no longer required HAVE_MEMORY_PRESENT configuration option.

Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20200712083130.22919-1-rppt@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-07 11:33:27 -07:00
Mike Rapoport f9cb654cb5 asm-generic: pgalloc: provide generic pgd_free()
Most architectures define pgd_free() as a wrapper for free_page().

Provide a generic version in asm-generic/pgalloc.h and enable its use for
most architectures.

Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Pekka Enberg <penberg@kernel.org>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>	[m68k]
Cc: Abdul Haleem <abdhalee@linux.vnet.ibm.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Joerg Roedel <jroedel@suse.de>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Satheesh Rajendran <sathnaga@linux.vnet.ibm.com>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Matthew Wilcox <willy@infradead.org>
Link: http://lkml.kernel.org/r/20200627143453.31835-7-rppt@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-07 11:33:26 -07:00
Mike Rapoport 1355c31eeb asm-generic: pgalloc: provide generic pmd_alloc_one() and pmd_free_one()
For most architectures that support >2 levels of page tables,
pmd_alloc_one() is a wrapper for __get_free_pages(), sometimes with
__GFP_ZERO and sometimes followed by memset(0) instead.

More elaborate versions on arm64 and x86 account memory for the user page
tables and call to pgtable_pmd_page_ctor() as the part of PMD page
initialization.

Move the arm64 version to include/asm-generic/pgalloc.h and use the
generic version on several architectures.

The pgtable_pmd_page_ctor() is a NOP when ARCH_ENABLE_SPLIT_PMD_PTLOCK is
not enabled, so there is no functional change for most architectures
except of the addition of __GFP_ACCOUNT for allocation of user page
tables.

The pmd_free() is a wrapper for free_page() in all the cases, so no
functional change here.

Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Pekka Enberg <penberg@kernel.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Abdul Haleem <abdhalee@linux.vnet.ibm.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Joerg Roedel <jroedel@suse.de>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Satheesh Rajendran <sathnaga@linux.vnet.ibm.com>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Link: http://lkml.kernel.org/r/20200627143453.31835-5-rppt@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-07 11:33:26 -07:00
Mike Rapoport ca15ca406f mm: remove unneeded includes of <asm/pgalloc.h>
Patch series "mm: cleanup usage of <asm/pgalloc.h>"

Most architectures have very similar versions of pXd_alloc_one() and
pXd_free_one() for intermediate levels of page table.  These patches add
generic versions of these functions in <asm-generic/pgalloc.h> and enable
use of the generic functions where appropriate.

In addition, functions declared and defined in <asm/pgalloc.h> headers are
used mostly by core mm and early mm initialization in arch and there is no
actual reason to have the <asm/pgalloc.h> included all over the place.
The first patch in this series removes unneeded includes of
<asm/pgalloc.h>

In the end it didn't work out as neatly as I hoped and moving
pXd_alloc_track() definitions to <asm-generic/pgalloc.h> would require
unnecessary changes to arches that have custom page table allocations, so
I've decided to move lib/ioremap.c to mm/ and make pgalloc-track.h local
to mm/.

This patch (of 8):

In most cases <asm/pgalloc.h> header is required only for allocations of
page table memory.  Most of the .c files that include that header do not
use symbols declared in <asm/pgalloc.h> and do not require that header.

As for the other header files that used to include <asm/pgalloc.h>, it is
possible to move that include into the .c file that actually uses symbols
from <asm/pgalloc.h> and drop the include from the header file.

The process was somewhat automated using

	sed -i -E '/[<"]asm\/pgalloc\.h/d' \
                $(grep -L -w -f /tmp/xx \
                        $(git grep -E -l '[<"]asm/pgalloc\.h'))

where /tmp/xx contains all the symbols defined in
arch/*/include/asm/pgalloc.h.

[rppt@linux.ibm.com: fix powerpc warning]

Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Pekka Enberg <penberg@kernel.org>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>	[m68k]
Cc: Abdul Haleem <abdhalee@linux.vnet.ibm.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Satheesh Rajendran <sathnaga@linux.vnet.ibm.com>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Joerg Roedel <jroedel@suse.de>
Cc: Matthew Wilcox <willy@infradead.org>
Link: http://lkml.kernel.org/r/20200627143453.31835-1-rppt@kernel.org
Link: http://lkml.kernel.org/r/20200627143453.31835-2-rppt@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-07 11:33:26 -07:00
Linus Torvalds 19b39c38ab Merge branch 'work.regset' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull ptrace regset updates from Al Viro:
 "Internal regset API changes:

   - regularize copy_regset_{to,from}_user() callers

   - switch to saner calling conventions for ->get()

   - kill user_regset_copyout()

  The ->put() side of things will have to wait for the next cycle,
  unfortunately.

  The balance is about -1KLoC and replacements for ->get() instances are
  a lot saner"

* 'work.regset' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (41 commits)
  regset: kill user_regset_copyout{,_zero}()
  regset(): kill ->get_size()
  regset: kill ->get()
  csky: switch to ->regset_get()
  xtensa: switch to ->regset_get()
  parisc: switch to ->regset_get()
  nds32: switch to ->regset_get()
  nios2: switch to ->regset_get()
  hexagon: switch to ->regset_get()
  h8300: switch to ->regset_get()
  openrisc: switch to ->regset_get()
  riscv: switch to ->regset_get()
  c6x: switch to ->regset_get()
  ia64: switch to ->regset_get()
  arc: switch to ->regset_get()
  arm: switch to ->regset_get()
  sh: convert to ->regset_get()
  arm64: switch to ->regset_get()
  mips: switch to ->regset_get()
  sparc: switch to ->regset_get()
  ...
2020-08-07 09:29:25 -07:00
Peter Zijlstra b3545192e2 locking, arch/ia64: Reduce <asm/smp.h> header dependencies by moving XTP bits into the new <asm/xtp.h> header
We want to remove the #include <asm/io.h> from <asm/smp.h>, but for this
we have to move the XTP bits into a separate header first (as these bits
rely on <asm/io.h> definitions), and include them in the .c files that rely
on those APIs.

Co-developed-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2020-08-06 16:13:13 +02:00
Linus Torvalds 47ec5303d7 Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next
Pull networking updates from David Miller:

 1) Support 6Ghz band in ath11k driver, from Rajkumar Manoharan.

 2) Support UDP segmentation in code TSO code, from Eric Dumazet.

 3) Allow flashing different flash images in cxgb4 driver, from Vishal
    Kulkarni.

 4) Add drop frames counter and flow status to tc flower offloading,
    from Po Liu.

 5) Support n-tuple filters in cxgb4, from Vishal Kulkarni.

 6) Various new indirect call avoidance, from Eric Dumazet and Brian
    Vazquez.

 7) Fix BPF verifier failures on 32-bit pointer arithmetic, from
    Yonghong Song.

 8) Support querying and setting hardware address of a port function via
    devlink, use this in mlx5, from Parav Pandit.

 9) Support hw ipsec offload on bonding slaves, from Jarod Wilson.

10) Switch qca8k driver over to phylink, from Jonathan McDowell.

11) In bpftool, show list of processes holding BPF FD references to
    maps, programs, links, and btf objects. From Andrii Nakryiko.

12) Several conversions over to generic power management, from Vaibhav
    Gupta.

13) Add support for SO_KEEPALIVE et al. to bpf_setsockopt(), from Dmitry
    Yakunin.

14) Various https url conversions, from Alexander A. Klimov.

15) Timestamping and PHC support for mscc PHY driver, from Antoine
    Tenart.

16) Support bpf iterating over tcp and udp sockets, from Yonghong Song.

17) Support 5GBASE-T i40e NICs, from Aleksandr Loktionov.

18) Add kTLS RX HW offload support to mlx5e, from Tariq Toukan.

19) Fix the ->ndo_start_xmit() return type to be netdev_tx_t in several
    drivers. From Luc Van Oostenryck.

20) XDP support for xen-netfront, from Denis Kirjanov.

21) Support receive buffer autotuning in MPTCP, from Florian Westphal.

22) Support EF100 chip in sfc driver, from Edward Cree.

23) Add XDP support to mvpp2 driver, from Matteo Croce.

24) Support MPTCP in sock_diag, from Paolo Abeni.

25) Commonize UDP tunnel offloading code by creating udp_tunnel_nic
    infrastructure, from Jakub Kicinski.

26) Several pci_ --> dma_ API conversions, from Christophe JAILLET.

27) Add FLOW_ACTION_POLICE support to mlxsw, from Ido Schimmel.

28) Add SK_LOOKUP bpf program type, from Jakub Sitnicki.

29) Refactor a lot of networking socket option handling code in order to
    avoid set_fs() calls, from Christoph Hellwig.

30) Add rfc4884 support to icmp code, from Willem de Bruijn.

31) Support TBF offload in dpaa2-eth driver, from Ioana Ciornei.

32) Support XDP_REDIRECT in qede driver, from Alexander Lobakin.

33) Support PCI relaxed ordering in mlx5 driver, from Aya Levin.

34) Support TCP syncookies in MPTCP, from Flowian Westphal.

35) Fix several tricky cases of PMTU handling wrt. briding, from Stefano
    Brivio.

* git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (2056 commits)
  net: thunderx: initialize VF's mailbox mutex before first usage
  usb: hso: remove bogus check for EINPROGRESS
  usb: hso: no complaint about kmalloc failure
  hso: fix bailout in error case of probe
  ip_tunnel_core: Fix build for archs without _HAVE_ARCH_IPV6_CSUM
  selftests/net: relax cpu affinity requirement in msg_zerocopy test
  mptcp: be careful on subflow creation
  selftests: rtnetlink: make kci_test_encap() return sub-test result
  selftests: rtnetlink: correct the final return value for the test
  net: dsa: sja1105: use detected device id instead of DT one on mismatch
  tipc: set ub->ifindex for local ipv6 address
  ipv6: add ipv6_dev_find()
  net: openvswitch: silence suspicious RCU usage warning
  Revert "vxlan: fix tos value before xmit"
  ptp: only allow phase values lower than 1 period
  farsync: switch from 'pci_' to 'dma_' API
  wan: wanxl: switch from 'pci_' to 'dma_' API
  hv_netvsc: do not use VF device if link is down
  dpaa2-eth: Fix passing zero to 'PTR_ERR' warning
  net: macb: Properly handle phylink on at91sam9x
  ...
2020-08-05 20:13:21 -07:00
Linus Torvalds 2324d50d05 It's been a busy cycle for documentation - hopefully the busiest for a
while to come.  Changes include:
 
  - Some new Chinese translations
 
  - Progress on the battle against double words words and non-HTTPS URLs
 
  - Some block-mq documentation
 
  - More RST conversions from Mauro.  At this point, that task is
    essentially complete, so we shouldn't see this kind of churn again for a
    while.  Unless we decide to switch to asciidoc or something...:)
 
  - Lots of typo fixes, warning fixes, and more.
 -----BEGIN PGP SIGNATURE-----
 
 iQFDBAABCAAtFiEEIw+MvkEiF49krdp9F0NaE2wMflgFAl8oVkwPHGNvcmJldEBs
 d24ubmV0AAoJEBdDWhNsDH5YoW8H/jJ/xnXFn7tkgVPQAlL3k5HCnK7A5nDP9RVR
 cg1pTx1cEFdjzxPlJyExU6/v+AImOvtweHXC+JDK7YcJ6XFUNYXJI3LxL5KwUXbY
 BL/xRFszDSXH2C7SJF5GECcFYp01e/FWSLN3yWAh+g+XwsKiTJ8q9+CoIDkHfPGO
 7oQsHKFu6s36Af0LfSgxk4sVB7EJbo8e4psuPsP5SUrl+oXRO43Put0rXkR4yJoH
 9oOaB51Do5fZp8I4JVAqGXvpXoExyLMO4yw0mASm6YSZ3KyjR8Fae+HD9Cq4ZuwY
 0uzb9K+9NEhqbfwtyBsi99S64/6Zo/MonwKwevZuhtsDTK4l4iU=
 =JQLZ
 -----END PGP SIGNATURE-----

Merge tag 'docs-5.9' of git://git.lwn.net/linux

Pull documentation updates from Jonathan Corbet:
 "It's been a busy cycle for documentation - hopefully the busiest for a
  while to come. Changes include:

   - Some new Chinese translations

   - Progress on the battle against double words words and non-HTTPS
     URLs

   - Some block-mq documentation

   - More RST conversions from Mauro. At this point, that task is
     essentially complete, so we shouldn't see this kind of churn again
     for a while. Unless we decide to switch to asciidoc or
     something...:)

   - Lots of typo fixes, warning fixes, and more"

* tag 'docs-5.9' of git://git.lwn.net/linux: (195 commits)
  scripts/kernel-doc: optionally treat warnings as errors
  docs: ia64: correct typo
  mailmap: add entry for <alobakin@marvell.com>
  doc/zh_CN: add cpu-load Chinese version
  Documentation/admin-guide: tainted-kernels: fix spelling mistake
  MAINTAINERS: adjust kprobes.rst entry to new location
  devices.txt: document rfkill allocation
  PCI: correct flag name
  docs: filesystems: vfs: correct flag name
  docs: filesystems: vfs: correct sync_mode flag names
  docs: path-lookup: markup fixes for emphasis
  docs: path-lookup: more markup fixes
  docs: path-lookup: fix HTML entity mojibake
  CREDITS: Replace HTTP links with HTTPS ones
  docs: process: Add an example for creating a fixes tag
  doc/zh_CN: add Chinese translation prefer section
  doc/zh_CN: add clearing-warn-once Chinese version
  doc/zh_CN: add admin-guide index
  doc:it_IT: process: coding-style.rst: Correct __maybe_unused compiler label
  futex: MAINTAINERS: Re-add selftests directory
  ...
2020-08-04 22:47:54 -07:00
Linus Torvalds 95ffa67658 Merge branch 'parisc-5.9-1' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux
Pull parisc updates from Helge Deller:
 "The majority of the patches are reverts of previous commits regarding
  the parisc-specific low level spinlocking code and barrier handling,
  with which we tried to fix CPU stalls on our build servers. In the end
  John David Anglin found the culprit: We missed a define for
  atomic64_set_release(). This seems to have fixed our issues, so now
  it's good to remove the unnecessary code again.

  Other than that it's trivial stuff: Spelling fixes, constifications
  and such"

* 'parisc-5.9-1' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux:
  parisc: make the log level string for register dumps const
  parisc: Do not use an ordered store in pa_tlb_lock()
  Revert "parisc: Revert "Release spinlocks using ordered store""
  Revert "parisc: Use ldcw instruction for SMP spinlock release barrier"
  Revert "parisc: Drop LDCW barrier in CAS code when running UP"
  Revert "parisc: Improve interrupt handling in arch_spin_lock_flags()"
  parisc: Replace HTTP links with HTTPS ones
  parisc: elf.h: delete a duplicated word
  parisc: Report bad pages as HardwareCorrupted
  parisc: Convert to BIT_MASK() and BIT_WORD()
2020-08-04 22:02:47 -07:00
Linus Torvalds 2ed90dbbf7 dma-mapping updates for 5.9
- make support for dma_ops optional
  - move more code out of line
  - add generic support for a dma_ops bypass mode
  - misc cleanups
 -----BEGIN PGP SIGNATURE-----
 
 iQI/BAABCgApFiEEgdbnc3r/njty3Iq9D55TZVIEUYMFAl8oGscLHGhjaEBsc3Qu
 ZGUACgkQD55TZVIEUYNfEhAAmFwd6BBHGwAhXUchoIue5vdNnuY3GiBFRzUdz67W
 zRYYgZYiPjl+MwflRmwPcoWEnGzmweRa2s6OnyDostiCRauioa8BuQfGqJasf1yZ
 D36dFNVHGW0o6pRDUQkd688k/4A6szwuwpq83qi4e8X2I9QzAITHtW8izjfPM923
 FlJzxEFggbB2TvwfUXOZhmpuG4Dog8S7VZ1Uz4QAg0Z/5FDqIKAAG2aZMqCXBbiX
 01E8tr0AqU/jn2xpc8O+DJGFiYIRhqhyNxQbH6qz1Q3xGFSokcLYm3YqkqVOgpn1
 DLs2UFDxWkly/F+wGnYtju7OD9VGPywzOcW125/LIsApYN5R/rYrtQzK41eq7Mp5
 HY3tqgNTIMdnl4so7QXeU4Vxj+lUdPlI26NZGszcM5AVftdTX8KjGdS+0+PBza6i
 i7trwG7J5/DnwiBCvEKoul7Ul1psUMTSvYwINTXRqsU4mZXhhx/mwyXbtruELnkj
 3agM98u6hoalLNjd2aueh+NjMZi1r+MchTrfRvTcxJ+yQ5BoR5kF+iz7eT/LtZ72
 AqWwimsPGNkLHUa0TrqWql5tv90cdDkBZzWXVbixwxRfgynWYLE6jugeIy8hwjFf
 GjO5XKbBwnWPjdSzFsVMPeuNpmr7ZjVHHewy2Q/jWQAIOyeof0VztEl23LN5yUkx
 pc8=
 =90UK
 -----END PGP SIGNATURE-----

Merge tag 'dma-mapping-5.9' of git://git.infradead.org/users/hch/dma-mapping

Pull dma-mapping updates from Christoph Hellwig:

 - make support for dma_ops optional

 - move more code out of line

 - add generic support for a dma_ops bypass mode

 - misc cleanups

* tag 'dma-mapping-5.9' of git://git.infradead.org/users/hch/dma-mapping:
  dma-contiguous: cleanup dma_alloc_contiguous
  dma-debug: use named initializers for dir2name
  powerpc: use the generic dma_ops_bypass mode
  dma-mapping: add a dma_ops_bypass flag to struct device
  dma-mapping: make support for dma ops optional
  dma-mapping: inline the fast path dma-direct calls
  dma-mapping: move the remaining DMA API calls out of line
2020-08-04 17:29:57 -07:00
Linus Torvalds 4f30a60aa7 close-range-v5.9
-----BEGIN PGP SIGNATURE-----
 
 iHUEABYKAB0WIQRAhzRXHqcMeLMyaSiRxhvAZXjcogUCXygcpgAKCRCRxhvAZXjc
 ogPeAQDv1ncqtNroFAC4pJ4tQhH7JSjW0OltiMk/AocY/J2SdQD9GJ15luYJ0/om
 697q/Z68sndRynhdoZlMuf3oYuBlHQw=
 =3ZhE
 -----END PGP SIGNATURE-----

Merge tag 'close-range-v5.9' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux

Pull close_range() implementation from Christian Brauner:
 "This adds the close_range() syscall. It allows to efficiently close a
  range of file descriptors up to all file descriptors of a calling
  task.

  This is coordinated with the FreeBSD folks which have copied our
  version of this syscall and in the meantime have already merged it in
  April 2019:

    https://reviews.freebsd.org/D21627
    https://svnweb.freebsd.org/base?view=revision&revision=359836

  The syscall originally came up in a discussion around the new mount
  API and making new file descriptor types cloexec by default. During
  this discussion, Al suggested the close_range() syscall.

  First, it helps to close all file descriptors of an exec()ing task.
  This can be done safely via (quoting Al's example from [1] verbatim):

        /* that exec is sensitive */
        unshare(CLONE_FILES);
        /* we don't want anything past stderr here */
        close_range(3, ~0U);
        execve(....);

  The code snippet above is one way of working around the problem that
  file descriptors are not cloexec by default. This is aggravated by the
  fact that we can't just switch them over without massively regressing
  userspace. For a whole class of programs having an in-kernel method of
  closing all file descriptors is very helpful (e.g. demons, service
  managers, programming language standard libraries, container managers
  etc.).

  Second, it allows userspace to avoid implementing closing all file
  descriptors by parsing through /proc/<pid>/fd/* and calling close() on
  each file descriptor and other hacks. From looking at various
  large(ish) userspace code bases this or similar patterns are very
  common in service managers, container runtimes, and programming
  language runtimes/standard libraries such as Python or Rust.

  In addition, the syscall will also work for tasks that do not have
  procfs mounted and on kernels that do not have procfs support compiled
  in. In such situations the only way to make sure that all file
  descriptors are closed is to call close() on each file descriptor up
  to UINT_MAX or RLIMIT_NOFILE, OPEN_MAX trickery.

  Based on Linus' suggestion close_range() also comes with a new flag
  CLOSE_RANGE_UNSHARE to more elegantly handle file descriptor dropping
  right before exec. This would usually be expressed in the sequence:

        unshare(CLONE_FILES);
        close_range(3, ~0U);

  as pointed out by Linus it might be desirable to have this be a part
  of close_range() itself under a new flag CLOSE_RANGE_UNSHARE which
  gets especially handy when we're closing all file descriptors above a
  certain threshold.

  Test-suite as always included"

* tag 'close-range-v5.9' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux:
  tests: add CLOSE_RANGE_UNSHARE tests
  close_range: add CLOSE_RANGE_UNSHARE
  tests: add close_range() tests
  arch: wire-up close_range()
  open: add close_range()
2020-08-04 15:12:02 -07:00
Linus Torvalds 9ba27414f2 fork-v5.9
-----BEGIN PGP SIGNATURE-----
 
 iHUEABYKAB0WIQRAhzRXHqcMeLMyaSiRxhvAZXjcogUCXyge/QAKCRCRxhvAZXjc
 oildAQCCWpnTeXm6hrIE3VZ36X5npFtbaEthdBVAUJM7mo0FYwEA8+Wbnubg6jCw
 mztkXCnTfU7tApUdhKtQzcpEws45/Qk=
 =REE/
 -----END PGP SIGNATURE-----

Merge tag 'fork-v5.9' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux

Pull fork cleanups from Christian Brauner:
 "This is cleanup series from when we reworked a chunk of the process
  creation paths in the kernel and switched to struct
  {kernel_}clone_args.

  High-level this does two main things:

   - Remove the double export of both do_fork() and _do_fork() where
     do_fork() used the incosistent legacy clone calling convention.

     Now we only export _do_fork() which is based on struct
     kernel_clone_args.

   - Remove the copy_thread_tls()/copy_thread() split making the
     architecture specific HAVE_COYP_THREAD_TLS config option obsolete.

  This switches all remaining architectures to select
  HAVE_COPY_THREAD_TLS and thus to the copy_thread_tls() calling
  convention. The current split makes the process creation codepaths
  more convoluted than they need to be. Each architecture has their own
  copy_thread() function unless it selects HAVE_COPY_THREAD_TLS then it
  has a copy_thread_tls() function.

  The split is not needed anymore nowadays, all architectures support
  CLONE_SETTLS but quite a few of them never bothered to select
  HAVE_COPY_THREAD_TLS and instead simply continued to use copy_thread()
  and use the old calling convention. Removing this split cleans up the
  process creation codepaths and paves the way for implementing clone3()
  on such architectures since it requires the copy_thread_tls() calling
  convention.

  After having made each architectures support copy_thread_tls() this
  series simply renames that function back to copy_thread(). It also
  switches all architectures that call do_fork() directly over to
  _do_fork() and the struct kernel_clone_args calling convention. This
  is a corollary of switching the architectures that did not yet support
  it over to copy_thread_tls() since do_fork() is conditional on not
  supporting copy_thread_tls() (Mostly because it lacks a separate
  argument for tls which is trivial to fix but there's no need for this
  function to exist.).

  The do_fork() removal is in itself already useful as it allows to to
  remove the export of both do_fork() and _do_fork() we currently have
  in favor of only _do_fork(). This has already been discussed back when
  we added clone3(). The legacy clone() calling convention is - as is
  probably well-known - somewhat odd:

    #
    # ABI hall of shame
    #
    config CLONE_BACKWARDS
    config CLONE_BACKWARDS2
    config CLONE_BACKWARDS3

  that is aggravated by the fact that some architectures such as sparc
  follow the CLONE_BACKWARDSx calling convention but don't really select
  the corresponding config option since they call do_fork() directly.

  So do_fork() enforces a somewhat arbitrary calling convention in the
  first place that doesn't really help the individual architectures that
  deviate from it. They can thus simply be switched to _do_fork()
  enforcing a single calling convention. (I really hope that any new
  architectures will __not__ try to implement their own calling
  conventions...)

  Most architectures already have made a similar switch (m68k comes to
  mind).

  Overall this removes more code than it adds even with a good portion
  of added comments. It simplifies a chunk of arch specific assembly
  either by moving the code into C or by simply rewriting the assembly.

  Architectures that have been touched in non-trivial ways have all been
  actually boot and stress tested: sparc and ia64 have been tested with
  Debian 9 images. They are the two architectures which have been
  touched the most. All non-trivial changes to architectures have seen
  acks from the relevant maintainers. nios2 with a custom built
  buildroot image. h8300 I couldn't get something bootable to test on
  but the changes have been fairly automatic and I'm sure we'll hear
  people yell if I broke something there.

  All other architectures that have been touched in trivial ways have
  been compile tested for each single patch of the series via git rebase
  -x "make ..." v5.8-rc2. arm{64} and x86{_64} have been boot tested
  even though they have just been trivially touched (removal of the
  HAVE_COPY_THREAD_TLS macro from their Kconfig) because well they are
  basically "core architectures" and since it is trivial to get your
  hands on a useable image"

* tag 'fork-v5.9' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux:
  arch: rename copy_thread_tls() back to copy_thread()
  arch: remove HAVE_COPY_THREAD_TLS
  unicore: switch to copy_thread_tls()
  sh: switch to copy_thread_tls()
  nds32: switch to copy_thread_tls()
  microblaze: switch to copy_thread_tls()
  hexagon: switch to copy_thread_tls()
  c6x: switch to copy_thread_tls()
  alpha: switch to copy_thread_tls()
  fork: remove do_fork()
  h8300: select HAVE_COPY_THREAD_TLS, switch to kernel_clone_args
  nios2: enable HAVE_COPY_THREAD_TLS, switch to kernel_clone_args
  ia64: enable HAVE_COPY_THREAD_TLS, switch to kernel_clone_args
  sparc: unconditionally enable HAVE_COPY_THREAD_TLS
  sparc: share process creation helpers between sparc and sparc64
  sparc64: enable HAVE_COPY_THREAD_TLS
  fork: fold legacy_clone_args_valid() into _do_fork()
2020-08-04 14:47:45 -07:00
Rolf Eike Beer e2693ec1e0 parisc: make the log level string for register dumps const
Signed-off-by: Rolf Eike Beer <eike-kernel@sf-tec.de>
Signed-off-by: Helge Deller <deller@gmx.de>
2020-08-04 16:22:53 +02:00
David S. Miller bd0b33b248 Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
Resolved kernel/bpf/btf.c using instructions from merge commit
69138b34a7

Signed-off-by: David S. Miller <davem@davemloft.net>
2020-08-02 01:02:12 -07:00
Ingo Molnar 28cff52eae Merge branch 'linus' into locking/core, to resolve conflict
Conflicts:
	arch/arm/include/asm/percpu.h

As Stephen Rothwell noted, there's a conflict between this commit
in locking/core:

  a21ee6055c ("lockdep: Change hardirq{s_enabled,_context} to per-cpu variables")

and this fresh upstream commit:

  aa54ea903a ("ARM: percpu.h: fix build error")

a21ee6055c is a simpler solution to the dependency problem and doesn't
further increase header hell - so this conflict resolution effectively
reverts aa54ea903a and uses the a21ee6055c solution.

Signed-off-by: Ingo Molnar <mingo@kernel.org>
2020-07-31 12:16:09 +02:00
Peter Zijlstra f05d67179d Merge branch 'locking/header' 2020-07-29 16:14:21 +02:00
Herbert Xu 7ca8cf5347 locking/atomic: Move ATOMIC_INIT into linux/types.h
This patch moves ATOMIC_INIT from asm/atomic.h into linux/types.h.
This allows users of atomic_t to use ATOMIC_INIT without having to
include atomic.h as that way may lead to header loops.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Waiman Long <longman@redhat.com>
Link: https://lkml.kernel.org/r/20200729123105.GB7047@gondor.apana.org.au
2020-07-29 16:14:18 +02:00
John David Anglin e72b23dec1 parisc: Do not use an ordered store in pa_tlb_lock()
No need to use an ordered store in pa_tlb_lock() and update the comment
regarng usage of the sid register to unlocak a spinlock in
tlb_unlock0().

Signed-off-by: John David Anglin <dave.anglin@bell.net>
Signed-off-by: Helge Deller <deller@gmx.de>
Cc: <stable@vger.kernel.org> # v5.0+
2020-07-28 19:29:38 +02:00
Helge Deller 157e9afcc4 Revert "parisc: Revert "Release spinlocks using ordered store""
This reverts commit 86d4d068df.

Signed-off-by: Helge Deller <deller@gmx.de>
Cc: <stable@vger.kernel.org> # v5.0+
2020-07-28 18:56:14 +02:00
Helge Deller 6e9f06ee6c Revert "parisc: Use ldcw instruction for SMP spinlock release barrier"
This reverts commit 9e5c602186.
No need to use the ldcw instruction as SMP spinlock release barrier.
Revert it to gain back speed again.

Signed-off-by: Helge Deller <deller@gmx.de>
Cc: <stable@vger.kernel.org> # v5.2+
2020-07-28 18:54:40 +02:00
Helge Deller 462fb756c7 Revert "parisc: Drop LDCW barrier in CAS code when running UP"
This reverts commit e6eb5fe912.
We need to optimize it differently. A follow up patch will correct it.

Signed-off-by: Helge Deller <deller@gmx.de>
Cc: <stable@vger.kernel.org> # v5.2+
2020-07-28 18:52:58 +02:00
Helge Deller 3d05b8aebc Revert "parisc: Improve interrupt handling in arch_spin_lock_flags()"
This reverts commit 2772f0efd5.
It turns out that we want to implement the spinlock code differently.

Signed-off-by: Helge Deller <deller@gmx.de>
Cc: <stable@vger.kernel.org> # v5.7+
2020-07-28 18:49:45 +02:00
Alexander A. Klimov 693a065433 parisc: Replace HTTP links with HTTPS ones
Reduces attack surface on kernel devs opening the links for MITM
as HTTPS traffic is much harder to manipulate.

Signed-off-by: Alexander A. Klimov <grandmaster@al2klimov.de>
Signed-off-by: Helge Deller <deller@gmx.de>
2020-07-28 11:22:08 +02:00
Randy Dunlap 961b658fea parisc: elf.h: delete a duplicated word
Drop the repeated word "the".

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: Helge Deller <deller@gmx.de>
Cc: linux-parisc@vger.kernel.org
Signed-off-by: Helge Deller <deller@gmx.de>
2020-07-28 11:22:05 +02:00
Helge Deller 0e5a7ff6e3 parisc: Report bad pages as HardwareCorrupted
The /proc/meminfo file reports physically broken memory pages in the
HardwareCorrupted field. When the parisc kernel boots report physically
bad pages which were recorded in the page deallocation table (PDT) as
HardwareCorrupted too.

Signed-off-by: Helge Deller <deller@gmx.de>
2020-07-28 11:19:17 +02:00
Al Viro bb1a773d5b kill unused dump_fpu() instances
dump_fpu() is used only on the architectures that support elf
and have neither CORE_DUMP_USE_REGSET nor ELF_CORE_COPY_FPREGS
defined.

Currently that's csky, m68k, microblaze, nds32 and unicore32.  The rest
of the instances are dead code.

NB: THIS MUST GO AFTER ELF_FDPIC CONVERSION

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2020-07-27 14:33:10 -04:00
Al Viro bd0409a856 parisc: switch to ->regset_get()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2020-07-27 14:31:12 -04:00
John David Anglin be6577af0c parisc: Add atomic64_set_release() define to avoid CPU soft lockups
Stalls are quite frequent with recent kernels. I enabled
CONFIG_SOFTLOCKUP_DETECTOR and I caught the following stall:

watchdog: BUG: soft lockup - CPU#0 stuck for 22s! [cc1:22803]
CPU: 0 PID: 22803 Comm: cc1 Not tainted 5.6.17+ #3
Hardware name: 9000/800/rp3440
 IAOQ[0]: d_alloc_parallel+0x384/0x688
 IAOQ[1]: d_alloc_parallel+0x388/0x688
 RP(r2): d_alloc_parallel+0x134/0x688
Backtrace:
 [<000000004036974c>] __lookup_slow+0xa4/0x200
 [<0000000040369fc8>] walk_component+0x288/0x458
 [<000000004036a9a0>] path_lookupat+0x88/0x198
 [<000000004036e748>] filename_lookup+0xa0/0x168
 [<000000004036e95c>] user_path_at_empty+0x64/0x80
 [<000000004035d93c>] vfs_statx+0x104/0x158
 [<000000004035dfcc>] __do_sys_lstat64+0x44/0x80
 [<000000004035e5a0>] sys_lstat64+0x20/0x38
 [<0000000040180054>] syscall_exit+0x0/0x14

The code was stuck in this loop in d_alloc_parallel:

    4037d414:   0e 00 10 dc     ldd 0(r16),ret0
    4037d418:   c7 fc 5f ed     bb,< ret0,1f,4037d414 <d_alloc_parallel+0x384>
    4037d41c:   08 00 02 40     nop

This is the inner loop of bit_spin_lock which is called by hlist_bl_unlock in
d_alloc_parallel:

static inline void bit_spin_lock(int bitnum, unsigned long *addr)
{
        /*
         * Assuming the lock is uncontended, this never enters
         * the body of the outer loop. If it is contended, then
         * within the inner loop a non-atomic test is used to
         * busywait with less bus contention for a good time to
         * attempt to acquire the lock bit.
         */
        preempt_disable();
#if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
        while (unlikely(test_and_set_bit_lock(bitnum, addr))) {
                preempt_enable();
                do {
                        cpu_relax();
                } while (test_bit(bitnum, addr));
                preempt_disable();
        }
#endif
        __acquire(bitlock);
}

After consideration, I realized that we must be losing bit unlocks.
Then, I noticed that we missed defining atomic64_set_release().
Adding this define fixes the stalls in bit operations.

Signed-off-by: Dave Anglin <dave.anglin@bell.net>
Cc: stable@vger.kernel.org
Signed-off-by: Helge Deller <deller@gmx.de>
2020-07-21 17:16:37 +02:00
Liam Beguin b344d6a83d parisc: add support for cmpxchg on u8 pointers
The kernel test bot reported[1] that using set_mask_bits on a u8 causes
the following issue on parisc:

	hppa-linux-ld: drivers/phy/ti/phy-tusb1210.o: in function `tusb1210_probe':
	>> (.text+0x2f4): undefined reference to `__cmpxchg_called_with_bad_pointer'
	>> hppa-linux-ld: (.text+0x324): undefined reference to `__cmpxchg_called_with_bad_pointer'
	hppa-linux-ld: (.text+0x354): undefined reference to `__cmpxchg_called_with_bad_pointer'

Add support for cmpxchg on u8 pointers.

[1] https://lore.kernel.org/patchwork/patch/1272617/#1468946

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Liam Beguin <liambeguin@gmail.com>
Tested-by: Dave Anglin <dave.anglin@bell.net>
Signed-off-by: Helge Deller <deller@gmx.de>
2020-07-21 08:11:12 +02:00
Helge Deller 208151bfb7 parisc: Convert to BIT_MASK() and BIT_WORD()
Drop own open-coded implementation to set bits and use the kernel
provided BIT_MASK() and BIT_WORD() macros.

Signed-off-by: Helge Deller <deller@gmx.de>
2020-07-21 08:04:39 +02:00
Christoph Hellwig 55db9c0e85 net: remove compat_sys_{get,set}sockopt
Now that the ->compat_{get,set}sockopt proto_ops methods are gone
there is no good reason left to keep the compat syscalls separate.

This fixes the odd use of unsigned int for the compat_setsockopt
optlen and the missing sock_use_custom_sol_socket.

It would also easily allow running the eBPF hooks for the compat
syscalls, but such a large change in behavior does not belong into
a consolidation patch like this one.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-07-19 18:16:40 -07:00
Christoph Hellwig 2f9237d4f6 dma-mapping: make support for dma ops optional
Avoid the overhead of the dma ops support for tiny builds that only
use the direct mapping.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru>
2020-07-19 09:29:23 +02:00
Christian Brauner 714acdbd1c
arch: rename copy_thread_tls() back to copy_thread()
Now that HAVE_COPY_THREAD_TLS has been removed, rename copy_thread_tls()
back simply copy_thread(). It's a simpler name, and doesn't imply that only
tls is copied here. This finishes an outstanding chunk of internal process
creation work since we've added clone3().

Cc: linux-arch@vger.kernel.org
Acked-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>A
Acked-by: Stafford Horne <shorne@gmail.com>
Acked-by: Greentime Hu <green.hu@gmail.com>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>A
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
2020-07-04 23:41:37 +02:00
Christian Brauner 140c8180eb
arch: remove HAVE_COPY_THREAD_TLS
All architectures support copy_thread_tls() now, so remove the legacy
copy_thread() function and the HAVE_COPY_THREAD_TLS config option. Everyone
uses the same process creation calling convention based on
copy_thread_tls() and struct kernel_clone_args. This will make it easier to
maintain the core process creation code under kernel/, simplifies the
callpaths and makes the identical for all architectures.

Cc: linux-arch@vger.kernel.org
Acked-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Acked-by: Greentime Hu <green.hu@gmail.com>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
2020-07-04 23:41:37 +02:00
Mauro Carvalho Chehab 985098a05e docs: fix references for DMA*.txt files
As we moved those files to core-api, fix references to point
to their newer locations.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/37b2fd159fbc7655dbf33b3eb1215396a25f6344.1592895969.git.mchehab+huawei@kernel.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2020-06-26 10:01:32 -06:00
Linus Torvalds 0c389d89ab maccess: make get_kernel_nofault() check for minimal type compatibility
Now that we've renamed probe_kernel_address() to get_kernel_nofault()
and made it look and behave more in line with get_user(), some of the
subtle type behavior differences end up being more obvious and possibly
dangerous.

When you do

        get_user(val, user_ptr);

the type of the access comes from the "user_ptr" part, and the above
basically acts as

        val = *user_ptr;

by design (except, of course, for the fact that the actual dereference
is done with a user access).

Note how in the above case, the type of the end result comes from the
pointer argument, and then the value is cast to the type of 'val' as
part of the assignment.

So the type of the pointer is ultimately the more important type both
for the access itself.

But 'get_kernel_nofault()' may now _look_ similar, but it behaves very
differently.  When you do

        get_kernel_nofault(val, kernel_ptr);

it behaves like

        val = *(typeof(val) *)kernel_ptr;

except, of course, for the fact that the actual dereference is done with
exception handling so that a faulting access is suppressed and returned
as the error code.

But note how different the casting behavior of the two superficially
similar accesses are: one does the actual access in the size of the type
the pointer points to, while the other does the access in the size of
the target, and ignores the pointer type entirely.

Actually changing get_kernel_nofault() to act like get_user() is almost
certainly the right thing to do eventually, but in the meantime this
patch adds logit to at least verify that the pointer type is compatible
with the type of the result.

In many cases, this involves just casting the pointer to 'void *' to
make it obvious that the type of the pointer is not the important part.
It's not how 'get_user()' acts, but at least the behavioral difference
is now obvious and explicit.

Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-06-18 12:10:37 -07:00