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  1. 11 2月, 2021 1 次提交
  3. 28 12月, 2020 1 次提交
  5. 23 12月, 2020 1 次提交
  7. 16 12月, 2020 4 次提交
    • M
      arch, mm: restore dependency of __kernel_map_pages() on DEBUG_PAGEALLOC · 5d6ad668
      由 Mike Rapoport 提交于 
      The design of DEBUG_PAGEALLOC presumes that __kernel_map_pages() must
never fail.  With this assumption is wouldn't be safe to allow general
usage of this function.

Moreover, some architectures that implement __kernel_map_pages() have this
function guarded by #ifdef DEBUG_PAGEALLOC and some refuse to map/unmap
pages when page allocation debugging is disabled at runtime.

As all the users of __kernel_map_pages() were converted to use
debug_pagealloc_map_pages() it is safe to make it available only when
DEBUG_PAGEALLOC is set.

Link: https://lkml.kernel.org/r/20201109192128.960-4-rppt@kernel.orgSigned-off-by: NMike Rapoport <rppt@linux.ibm.com>
Acked-by: NDavid Hildenbrand <david@redhat.com>
Acked-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Rientjes <rientjes@google.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: "Edgecombe, Rick P" <rick.p.edgecombe@intel.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Len Brown <len.brown@intel.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      5d6ad668
    • M
      arm, arm64: move free_unused_memmap() to generic mm · 4f5b0c17
      由 Mike Rapoport 提交于 
      ARM and ARM64 free unused parts of the memory map just before the
initialization of the page allocator. To allow holes in the memory map both
architectures overload pfn_valid() and define HAVE_ARCH_PFN_VALID.

Allowing holes in the memory map for FLATMEM may be useful for small
machines, such as ARC and m68k and will enable those architectures to cease
using DISCONTIGMEM and still support more than one memory bank.

Move the functions that free unused memory map to generic mm and enable
them in case HAVE_ARCH_PFN_VALID=y.

Link: https://lkml.kernel.org/r/20201101170454.9567-10-rppt@kernel.orgSigned-off-by: NMike Rapoport <rppt@linux.ibm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>	[arm64]
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Greg Ungerer <gerg@linux-m68k.org>
Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Meelis Roos <mroos@linux.ee>
Cc: Michael Schmitz <schmitzmic@gmail.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      4f5b0c17
    • K
      mm: speedup mremap on 1GB or larger regions · c49dd340
      由 Kalesh Singh 提交于 
      Android needs to move large memory regions for garbage collection.  The GC
requires moving physical pages of multi-gigabyte heap using mremap.
During this move, the application threads have to be paused for
correctness.  It is critical to keep this pause as short as possible to
avoid jitters during user interaction.

Optimize mremap for >= 1GB-sized regions by moving at the PUD/PGD level if
the source and destination addresses are PUD-aligned.  For
CONFIG_PGTABLE_LEVELS == 3, moving at the PUD level in effect moves PGD
entries, since the PUD entry is “folded back” onto the PGD entry.  Add
HAVE_MOVE_PUD so that architectures where moving at the PUD level isn't
supported/tested can turn this off by not selecting the config.

Link: https://lkml.kernel.org/r/20201014005320.2233162-4-kaleshsingh@google.comSigned-off-by: NKalesh Singh <kaleshsingh@google.com>
Acked-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reported-by: Nkernel test robot <lkp@intel.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Geffon <bgeffon@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Brauner <christian.brauner@ubuntu.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Frederic Weisbecker <frederic@kernel.org>
Cc: Gavin Shan <gshan@redhat.com>
Cc: Hassan Naveed <hnaveed@wavecomp.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jia He <justin.he@arm.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Krzysztof Kozlowski <krzk@kernel.org>
Cc: Lokesh Gidra <lokeshgidra@google.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Mina Almasry <almasrymina@google.com>
Cc: Minchan Kim <minchan@google.com>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Ram Pai <linuxram@us.ibm.com>
Cc: Sami Tolvanen <samitolvanen@google.com>
Cc: Sandipan Das <sandipan@linux.ibm.com>
Cc: SeongJae Park <sjpark@amazon.de>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Steven Price <steven.price@arm.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      c49dd340
    • C
      arch/Kconfig: fix spelling mistakes · a86ecfa6
      由 Colin Ian King 提交于 
      There are a few spelling mistakes in the Kconfig comments and help text.
Fix these.

Link: https://lkml.kernel.org/r/20201207155004.171962-1-colin.king@canonical.comSigned-off-by: NColin Ian King <colin.king@canonical.com>
Acked-by: NRandy Dunlap <rdunlap@infradead.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      a86ecfa6
  9. 15 12月, 2020 1 次提交
    • S
      Revert: "ring-buffer: Remove HAVE_64BIT_ALIGNED_ACCESS" · adab66b7
      由 Steven Rostedt (VMware) 提交于 
      It was believed that metag was the only architecture that required the ring
buffer to keep 8 byte words aligned on 8 byte architectures, and with its
removal, it was assumed that the ring buffer code did not need to handle
this case. It appears that sparc64 also requires this.

The following was reported on a sparc64 boot up:

   kernel: futex hash table entries: 65536 (order: 9, 4194304 bytes, linear)
   kernel: Running postponed tracer tests:
   kernel: Testing tracer function:
   kernel: Kernel unaligned access at TPC[552a20] trace_function+0x40/0x140
   kernel: Kernel unaligned access at TPC[552a24] trace_function+0x44/0x140
   kernel: Kernel unaligned access at TPC[552a20] trace_function+0x40/0x140
   kernel: Kernel unaligned access at TPC[552a24] trace_function+0x44/0x140
   kernel: Kernel unaligned access at TPC[552a20] trace_function+0x40/0x140
   kernel: PASSED

Need to put back the 64BIT aligned code for the ring buffer.

Link: https://lore.kernel.org/r/CADxRZqzXQRYgKc=y-KV=S_yHL+Y8Ay2mh5ezeZUnpRvg+syWKw@mail.gmail.com

Cc: stable@vger.kernel.org
Fixes: 86b3de60 ("ring-buffer: Remove HAVE_64BIT_ALIGNED_ACCESS")
Reported-by: NAnatoly Pugachev <matorola@gmail.com>
Signed-off-by: NSteven Rostedt (VMware) <rostedt@goodmis.org>
      adab66b7
  11. 03 12月, 2020 1 次提交
  13. 01 12月, 2020 1 次提交
  15. 21 11月, 2020 1 次提交
  17. 19 11月, 2020 1 次提交
    • F
      context_tracking: Introduce HAVE_CONTEXT_TRACKING_OFFSTACK · 83c2da2e
      由 Frederic Weisbecker 提交于 
      Historically, context tracking had to deal with fragile entry code path,
ie: before user_exit() is called and after user_enter() is called, in
case some of those spots would call schedule() or use RCU. On such
cases, the site had to be protected between exception_enter() and
exception_exit() that save the context tracking state in the task stack.

Such sleepable fragile code path had many different origins: tracing,
exceptions, early or late calls to context tracking on syscalls...

Aside of that not being pretty, saving the context tracking state on
the task stack forces us to run context tracking on all CPUs, including
housekeepers, and prevents us to completely shutdown nohz_full at
runtime on a CPU in the future as context tracking and its overhead
would still need to run system wide.

Now thanks to the extensive efforts to sanitize x86 entry code, those
conditions have been removed and we can now get rid of these workarounds
in this architecture.

Create a Kconfig feature to express this achievement.
Signed-off-by: NFrederic Weisbecker <frederic@kernel.org>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20201117151637.259084-2-frederic@kernel.org
      83c2da2e
  19. 09 10月, 2020 1 次提交
  21. 16 9月, 2020 1 次提交
    • N
      mm: fix exec activate_mm vs TLB shootdown and lazy tlb switching race · d53c3dfb
      由 Nicholas Piggin 提交于 
      Reading and modifying current->mm and current->active_mm and switching
mm should be done with irqs off, to prevent races seeing an intermediate
state.

This is similar to commit 38cf307c ("mm: fix kthread_use_mm() vs TLB
invalidate"). At exec-time when the new mm is activated, the old one
should usually be single-threaded and no longer used, unless something
else is holding an mm_users reference (which may be possible).

Absent other mm_users, there is also a race with preemption and lazy tlb
switching. Consider the kernel_execve case where the current thread is
using a lazy tlb active mm:

  call_usermodehelper()
    kernel_execve()
      old_mm = current->mm;
      active_mm = current->active_mm;
      *** preempt *** -------------------->  schedule()
                                               prev->active_mm = NULL;
                                               mmdrop(prev active_mm);
                                             ...
                      <--------------------  schedule()
      current->mm = mm;
      current->active_mm = mm;
      if (!old_mm)
          mmdrop(active_mm);

If we switch back to the kernel thread from a different mm, there is a
double free of the old active_mm, and a missing free of the new one.

Closing this race only requires interrupts to be disabled while ->mm
and ->active_mm are being switched, but the TLB problem requires also
holding interrupts off over activate_mm. Unfortunately not all archs
can do that yet, e.g., arm defers the switch if irqs are disabled and
expects finish_arch_post_lock_switch() to be called to complete the
flush; um takes a blocking lock in activate_mm().

So as a first step, disable interrupts across the mm/active_mm updates
to close the lazy tlb preempt race, and provide an arch option to
extend that to activate_mm which allows architectures doing IPI based
TLB shootdowns to close the second race.

This is a bit ugly, but in the interest of fixing the bug and backporting
before all architectures are converted this is a compromise.
Signed-off-by: NNicholas Piggin <npiggin@gmail.com>
Acked-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200914045219.3736466-2-npiggin@gmail.com
      d53c3dfb
  23. 09 9月, 2020 1 次提交
  25. 01 9月, 2020 3 次提交
  27. 06 8月, 2020 1 次提交
  29. 24 7月, 2020 1 次提交
    • T
      entry: Provide generic syscall entry functionality · 142781e1
      由 Thomas Gleixner 提交于 
      On syscall entry certain work needs to be done:

   - Establish state (lockdep, context tracking, tracing)
   - Conditional work (ptrace, seccomp, audit...)

This code is needlessly duplicated and  different in all
architectures.

Provide a generic version based on the x86 implementation which has all the
RCU and instrumentation bits right.

As interrupt/exception entry from user space needs parts of the same
functionality, provide a function for this as well.

syscall_enter_from_user_mode() and irqentry_enter_from_user_mode() must be
called right after the low level ASM entry. The calling code must be
non-instrumentable. After the functions returns state is correct and the
subsequent functions can be instrumented.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Acked-by: NKees Cook <keescook@chromium.org>
Link: https://lkml.kernel.org/r/20200722220519.513463269@linutronix.de
      142781e1
  31. 07 7月, 2020 1 次提交
  33. 05 7月, 2020 1 次提交
  35. 27 6月, 2020 1 次提交
  37. 14 6月, 2020 1 次提交
    • M
      treewide: replace '---help---' in Kconfig files with 'help' · a7f7f624
      由 Masahiro Yamada 提交于 
      Since commit 84af7a61 ("checkpatch: kconfig: prefer 'help' over
'---help---'"), the number of '---help---' has been gradually
decreasing, but there are still more than 2400 instances.

This commit finishes the conversion. While I touched the lines,
I also fixed the indentation.

There are a variety of indentation styles found.

  a) 4 spaces + '---help---'
  b) 7 spaces + '---help---'
  c) 8 spaces + '---help---'
  d) 1 space + 1 tab + '---help---'
  e) 1 tab + '---help---'    (correct indentation)
  f) 1 tab + 1 space + '---help---'
  g) 1 tab + 2 spaces + '---help---'

In order to convert all of them to 1 tab + 'help', I ran the
following commend:

  $ find . -name 'Kconfig*' | xargs sed -i 's/^[[:space:]]*---help---/\thelp/'
Signed-off-by: NMasahiro Yamada <masahiroy@kernel.org>
      a7f7f624
  39. 19 5月, 2020 1 次提交
  41. 15 5月, 2020 2 次提交
    • S
      scs: Disable when function graph tracing is enabled · ddc9863e
      由 Sami Tolvanen 提交于 
      The graph tracer hooks returns by modifying frame records on the
(regular) stack, but with SCS the return address is taken from the
shadow stack, and the value in the frame record has no effect. As we
don't currently have a mechanism to determine the corresponding slot
on the shadow stack (and to pass this through the ftrace
infrastructure), for now let's disable SCS when the graph tracer is
enabled.

With SCS the return address is taken from the shadow stack and the
value in the frame record has no effect. The mcount based graph tracer
hooks returns by modifying frame records on the (regular) stack, and
thus is not compatible. The patchable-function-entry graph tracer
used for DYNAMIC_FTRACE_WITH_REGS modifies the LR before it is saved
to the shadow stack, and is compatible.

Modifying the mcount based graph tracer to work with SCS would require
a mechanism to determine the corresponding slot on the shadow stack
(and to pass this through the ftrace infrastructure), and we expect
that everyone will eventually move to the patchable-function-entry
based graph tracer anyway, so for now let's disable SCS when the
mcount-based graph tracer is enabled.

SCS and patchable-function-entry are both supported from LLVM 10.x.
Signed-off-by: NSami Tolvanen <samitolvanen@google.com>
Reviewed-by: NKees Cook <keescook@chromium.org>
Reviewed-by: NMark Rutland <mark.rutland@arm.com>
Signed-off-by: NWill Deacon <will@kernel.org>
      ddc9863e
    • S
      scs: Add support for Clang's Shadow Call Stack (SCS) · d08b9f0c
      由 Sami Tolvanen 提交于 
      This change adds generic support for Clang's Shadow Call Stack,
which uses a shadow stack to protect return addresses from being
overwritten by an attacker. Details are available here:

  https://clang.llvm.org/docs/ShadowCallStack.html

Note that security guarantees in the kernel differ from the ones
documented for user space. The kernel must store addresses of
shadow stacks in memory, which means an attacker capable reading
and writing arbitrary memory may be able to locate them and hijack
control flow by modifying the stacks.
Signed-off-by: NSami Tolvanen <samitolvanen@google.com>
Reviewed-by: NKees Cook <keescook@chromium.org>
Reviewed-by: NMiguel Ojeda <miguel.ojeda.sandonis@gmail.com>
[will: Numerous cosmetic changes]
Signed-off-by: NWill Deacon <will@kernel.org>
      d08b9f0c
  43. 13 5月, 2020 1 次提交
  45. 16 3月, 2020 3 次提交
  47. 06 3月, 2020 1 次提交
  49. 14 2月, 2020 1 次提交
    • F
      context-tracking: Introduce CONFIG_HAVE_TIF_NOHZ · 490f561b
      由 Frederic Weisbecker 提交于 
      A few archs (x86, arm, arm64) don't rely anymore on TIF_NOHZ to call
into context tracking on user entry/exit but instead use static keys
(or not) to optimize those calls. Ideally every arch should migrate to
that behaviour in the long run.

Settle a config option to let those archs remove their TIF_NOHZ
definitions.
Signed-off-by: NFrederic Weisbecker <frederic@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Paul Burton <paulburton@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: David S. Miller <davem@davemloft.net>
      490f561b
  51. 04 2月, 2020 6 次提交
  53. 05 12月, 2019 1 次提交