Skip to content

cloud-kernel
cloud-kernel

openanolis / cloud-kernel
1 年多 前同步成功

通知 161
Star 36
Fork 7
cloud-kernel
cloud-kernel
切换分支/标签
  1. 02 8月, 2016 1 次提交
    • P
      MIPS: Use per-mm page to execute branch delay slot instructions · 432c6bac
      由 Paul Burton 提交于 
      In some cases the kernel needs to execute an instruction from the delay
slot of an emulated branch instruction. These cases include:

  - Emulated floating point branch instructions (bc1[ft]l?) for systems
    which don't include an FPU, or upon which the kernel is run with the
    "nofpu" parameter.

  - MIPSr6 systems running binaries targeting older revisions of the
    architecture, which may include branch instructions whose encodings
    are no longer valid in MIPSr6.

Executing instructions from such delay slots is done by writing the
instruction to memory followed by a trap, as part of an "emuframe", and
executing it. This avoids the requirement of an emulator for the entire
MIPS instruction set. Prior to this patch such emuframes are written to
the user stack and executed from there.

This patch moves FP branch delay emuframes off of the user stack and
into a per-mm page. Allocating a page per-mm leaves userland with access
to only what it had access to previously, and compared to other
solutions is relatively simple.

When a thread requires a delay slot emulation, it is allocated a frame.
A thread may only have one frame allocated at any one time, since it may
only ever be executing one instruction at any one time. In order to
ensure that we can free up allocated frame later, its index is recorded
in struct thread_struct. In the typical case, after executing the delay
slot instruction we'll execute a break instruction with the BRK_MEMU
code. This traps back to the kernel & leads to a call to do_dsemulret
which frees the allocated frame & moves the user PC back to the
instruction that would have executed following the emulated branch.
In some cases the delay slot instruction may be invalid, such as a
branch, or may trigger an exception. In these cases the BRK_MEMU break
instruction will not be hit. In order to ensure that frames are freed
this patch introduces dsemul_thread_cleanup() and calls it to free any
allocated frame upon thread exit. If the instruction generated an
exception & leads to a signal being delivered to the thread, or indeed
if a signal simply happens to be delivered to the thread whilst it is
executing from the struct emuframe, then we need to take care to exit
the frame appropriately. This is done by either rolling back the user PC
to the branch or advancing it to the continuation PC prior to signal
delivery, using dsemul_thread_rollback(). If this were not done then a
sigreturn would return to the struct emuframe, and if that frame had
meanwhile been used in response to an emulated branch instruction within
the signal handler then we would execute the wrong user code.

Whilst a user could theoretically place something like a compact branch
to self in a delay slot and cause their thread to become stuck in an
infinite loop with the frame never being deallocated, this would:

  - Only affect the users single process.

  - Be architecturally invalid since there would be a branch in the
    delay slot, which is forbidden.

  - Be extremely unlikely to happen by mistake, and provide a program
    with no more ability to harm the system than a simple infinite loop
    would.

If a thread requires a delay slot emulation & no frame is available to
it (ie. the process has enough other threads that all frames are
currently in use) then the thread joins a waitqueue. It will sleep until
a frame is freed by another thread in the process.

Since we now know whether a thread has an allocated frame due to our
tracking of its index, the cookie field of struct emuframe is removed as
we can be more certain whether we have a valid frame. Since a thread may
only ever have a single frame at any given time, the epc field of struct
emuframe is also removed & the PC to continue from is instead stored in
struct thread_struct. Together these changes simplify & shrink struct
emuframe somewhat, allowing twice as many frames to fit into the page
allocated for them.

The primary benefit of this patch is that we are now free to mark the
user stack non-executable where that is possible.
Signed-off-by: NPaul Burton <paul.burton@imgtec.com>
Cc: Leonid Yegoshin <leonid.yegoshin@imgtec.com>
Cc: Maciej Rozycki <maciej.rozycki@imgtec.com>
Cc: Faraz Shahbazker <faraz.shahbazker@imgtec.com>
Cc: Raghu Gandham <raghu.gandham@imgtec.com>
Cc: Matthew Fortune <matthew.fortune@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/13764/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>
      432c6bac
  3. 24 7月, 2016 3 次提交
  5. 12 7月, 2016 1 次提交
  7. 28 5月, 2016 1 次提交
  9. 24 5月, 2016 1 次提交
    • R
      ELF/MIPS build fix · f43edca7
      由 Ralf Baechle 提交于 
      CONFIG_MIPS32_N32=y but CONFIG_BINFMT_ELF disabled results in the
following linker errors:

  arch/mips/built-in.o: In function `elf_core_dump':
  binfmt_elfn32.c:(.text+0x23dbc): undefined reference to `elf_core_extra_phdrs'
  binfmt_elfn32.c:(.text+0x246e4): undefined reference to `elf_core_extra_data_size'
  binfmt_elfn32.c:(.text+0x248d0): undefined reference to `elf_core_write_extra_phdrs'
  binfmt_elfn32.c:(.text+0x24ac4): undefined reference to `elf_core_write_extra_data'

CONFIG_MIPS32_O32=y but CONFIG_BINFMT_ELF disabled results in the following
linker errors:

  arch/mips/built-in.o: In function `elf_core_dump':
  binfmt_elfo32.c:(.text+0x28a04): undefined reference to `elf_core_extra_phdrs'
  binfmt_elfo32.c:(.text+0x29330): undefined reference to `elf_core_extra_data_size'
  binfmt_elfo32.c:(.text+0x2951c): undefined reference to `elf_core_write_extra_phdrs'
  binfmt_elfo32.c:(.text+0x29710): undefined reference to `elf_core_write_extra_data'

This is because binfmt_elfn32 and binfmt_elfo32 are using symbols from
elfcore but for these configurations elfcore will not be built.

Fixed by making elfcore selectable by a separate config symbol which
unlike the current mechanism can also be used from other directories
than kernel/, then having each flavor of ELF that relies on elfcore.o,
select it in Kconfig, including CONFIG_MIPS32_N32 and CONFIG_MIPS32_O32
which fixes this issue.

Link: http://lkml.kernel.org/r/20160520141705.GA1913@linux-mips.orgSigned-off-by: NRalf Baechle <ralf@linux-mips.org>
Reviewed-by: NJames Hogan <james.hogan@imgtec.com>
Cc: "Maciej W. Rozycki" <macro@linux-mips.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      f43edca7
  11. 21 5月, 2016 1 次提交
    • P
      printk/nmi: generic solution for safe printk in NMI · 42a0bb3f
      由 Petr Mladek 提交于 
      printk() takes some locks and could not be used a safe way in NMI
context.

The chance of a deadlock is real especially when printing stacks from
all CPUs.  This particular problem has been addressed on x86 by the
commit a9edc880 ("x86/nmi: Perform a safe NMI stack trace on all
CPUs").

The patchset brings two big advantages.  First, it makes the NMI
backtraces safe on all architectures for free.  Second, it makes all NMI
messages almost safe on all architectures (the temporary buffer is
limited.  We still should keep the number of messages in NMI context at
minimum).

Note that there already are several messages printed in NMI context:
WARN_ON(in_nmi()), BUG_ON(in_nmi()), anything being printed out from MCE
handlers.  These are not easy to avoid.

This patch reuses most of the code and makes it generic.  It is useful
for all messages and architectures that support NMI.

The alternative printk_func is set when entering and is reseted when
leaving NMI context.  It queues IRQ work to copy the messages into the
main ring buffer in a safe context.

__printk_nmi_flush() copies all available messages and reset the buffer.
Then we could use a simple cmpxchg operations to get synchronized with
writers.  There is also used a spinlock to get synchronized with other
flushers.

We do not longer use seq_buf because it depends on external lock.  It
would be hard to make all supported operations safe for a lockless use.
It would be confusing and error prone to make only some operations safe.

The code is put into separate printk/nmi.c as suggested by Steven
Rostedt.  It needs a per-CPU buffer and is compiled only on
architectures that call nmi_enter().  This is achieved by the new
HAVE_NMI Kconfig flag.

The are MN10300 and Xtensa architectures.  We need to clean up NMI
handling there first.  Let's do it separately.

The patch is heavily based on the draft from Peter Zijlstra, see

  https://lkml.org/lkml/2015/6/10/327

[arnd@arndb.de: printk-nmi: use %zu format string for size_t]
[akpm@linux-foundation.org: min_t->min - all types are size_t here]
Signed-off-by: NPetr Mladek <pmladek@suse.com>
Suggested-by: NPeter Zijlstra <peterz@infradead.org>
Suggested-by: NSteven Rostedt <rostedt@goodmis.org>
Cc: Jan Kara <jack@suse.cz>
Acked-by: Russell King <rmk+kernel@arm.linux.org.uk>	[arm part]
Cc: Daniel Thompson <daniel.thompson@linaro.org>
Cc: Jiri Kosina <jkosina@suse.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: David Miller <davem@davemloft.net>
Cc: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      42a0bb3f
  13. 17 5月, 2016 1 次提交
    • D
      bpf: split HAVE_BPF_JIT into cBPF and eBPF variant · 6077776b
      由 Daniel Borkmann 提交于 
      Split the HAVE_BPF_JIT into two for distinguishing cBPF and eBPF JITs.

Current cBPF ones:

  # git grep -n HAVE_CBPF_JIT arch/
  arch/arm/Kconfig:44:    select HAVE_CBPF_JIT
  arch/mips/Kconfig:18:   select HAVE_CBPF_JIT if !CPU_MICROMIPS
  arch/powerpc/Kconfig:129:       select HAVE_CBPF_JIT
  arch/sparc/Kconfig:35:  select HAVE_CBPF_JIT

Current eBPF ones:

  # git grep -n HAVE_EBPF_JIT arch/
  arch/arm64/Kconfig:61:  select HAVE_EBPF_JIT
  arch/s390/Kconfig:126:  select HAVE_EBPF_JIT if PACK_STACK && HAVE_MARCH_Z196_FEATURES
  arch/x86/Kconfig:94:    select HAVE_EBPF_JIT                    if X86_64

Later code also needs this facility to check for eBPF JITs.
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Acked-by: NAlexei Starovoitov <ast@kernel.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      6077776b
  15. 13 5月, 2016 19 次提交
  17. 11 5月, 2016 1 次提交
    • L
      MIPS: do away with ARCH_[WANT_OPTIONAL|REQUIRE]_GPIOLIB · d30a2b47
      由 Linus Walleij 提交于 
      This replaces:

- "select ARCH_REQUIRE_GPIOLIB" with "select GPIOLIB" as this can
  now be selected directly.

- "select ARCH_WANT_OPTIONAL_GPIOLIB" with no dependency: GPIOLIB
  is now selectable by everyone, so we need not declare our
  intent to select it.

When ordering the symbols the following rationale was used:
if the selects were in alphabetical order, I moved select GPIOLIB
to be in alphabetical order, but if the selects were not
maintained in alphabetical order, I just replaced
"select ARCH_REQUIRE_GPIOLIB" with "select GPIOLIB".

Cc: Michael Büsch <m@bues.ch>
Cc: linux-mips@linux-mips.org
Acked-by: NRalf Baechle <ralf@linux-mips.org>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>
      d30a2b47
  19. 09 5月, 2016 1 次提交
  21. 13 3月, 2016 1 次提交
  23. 09 3月, 2016 2 次提交
    • B
      PCI: Include pci/hotplug Kconfig directly from pci/Kconfig · e7e127e3
      由 Bjorn Helgaas 提交于 
      Include pci/hotplug/Kconfig directly from pci/Kconfig, so arches don't
have to source both pci/Kconfig and pci/hotplug/Kconfig.

Note that this effectively adds pci/hotplug/Kconfig to the following
arches, because they already sourced drivers/pci/Kconfig but they
previously did not source drivers/pci/hotplug/Kconfig:

  alpha
  arm
  avr32
  frv
  m68k
  microblaze
  mn10300
  sparc
  unicore32

Inspired-by-patch-from: Bogicevic Sasa <brutallesale@gmail.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
      e7e127e3
    • B
      PCI: Include pci/pcie/Kconfig directly from pci/Kconfig · 5f8fc432
      由 Bogicevic Sasa 提交于 
      Include pci/pcie/Kconfig directly from pci/Kconfig, so arches don't
have to source both pci/Kconfig and pci/pcie/Kconfig.

Note that this effectively adds pci/pcie/Kconfig to the following
arches, because they already sourced drivers/pci/Kconfig but they
previously did not source drivers/pci/pcie/Kconfig:

  alpha
  avr32
  blackfin
  frv
  m32r
  m68k
  microblaze
  mn10300
  parisc
  sparc
  unicore32
  xtensa

[bhelgaas: changelog, source pci/pcie/Kconfig at top of pci/Kconfig, whitespace]
Signed-off-by: NSasa Bogicevic <brutallesale@gmail.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
      5f8fc432
  25. 26 2月, 2016 1 次提交
  27. 25 2月, 2016 1 次提交
  29. 08 2月, 2016 1 次提交
    • S
      irqchips/bmips: Add bcm6345-l1 interrupt controller · c7c42ec2
      由 Simon Arlott 提交于 
      Add the BCM6345 interrupt controller based on the SMP-capable BCM7038
and the BCM3380 but with packed interrupt registers.

Add the BCM6345 interrupt controller to a list with the existing BCM7038
so that interrupts on CPU1 are not ignored.

Update the maintainers file list for BMIPS to include this driver.
Signed-off-by: NSimon Arlott <simon@fire.lp0.eu>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: devicetree@vger.kernel.org
Cc: Ian Campbell <ijc+devicetree@hellion.org.uk>
Cc: Florian Fainelli <f.fainelli@gmail.com>
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: Pawel Moll <pawel.moll@arm.com>
Cc: linux-mips@linux-mips.org
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Kevin Cernekee <cernekee@gmail.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Jonas Gorski <jogo@openwrt.org>
Cc: Kumar Gala <galak@codeaurora.org>
Cc: Rob Herring <robh@kernel.org>
Link: http://lkml.kernel.org/r/5651D176.6030908@simon.arlott.org.ukSigned-off-by: NThomas Gleixner <tglx@linutronix.de>
      c7c42ec2
  31. 03 2月, 2016 1 次提交
  33. 24 1月, 2016 3 次提交