linux-toradex.git/arch/mn10300, branch v3.10.84

vm: add VM_FAULT_SIGSEGV handling support

2015-04-29T08:34:00+00:00

commit 33692f27597fcab536d7cbbcc8f52905133e4aa7 upstream.

The core VM already knows about VM_FAULT_SIGBUS, but cannot return a
"you should SIGSEGV" error, because the SIGSEGV case was generally
handled by the caller - usually the architecture fault handler.

That results in lots of duplication - all the architecture fault
handlers end up doing very similar "look up vma, check permissions, do
retries etc" - but it generally works.  However, there are cases where
the VM actually wants to SIGSEGV, and applications _expect_ SIGSEGV.

In particular, when accessing the stack guard page, libsigsegv expects a
SIGSEGV.  And it usually got one, because the stack growth is handled by
that duplicated architecture fault handler.

However, when the generic VM layer started propagating the error return
from the stack expansion in commit fee7e49d4514 ("mm: propagate error
from stack expansion even for guard page"), that now exposed the
existing VM_FAULT_SIGBUS result to user space.  And user space really
expected SIGSEGV, not SIGBUS.

To fix that case, we need to add a VM_FAULT_SIGSEGV, and teach all those
duplicate architecture fault handlers about it.  They all already have
the code to handle SIGSEGV, so it's about just tying that new return
value to the existing code, but it's all a bit annoying.

This is the mindless minimal patch to do this.  A more extensive patch
would be to try to gather up the mostly shared fault handling logic into
one generic helper routine, and long-term we really should do that
cleanup.

Just from this patch, you can generally see that most architectures just
copied (directly or indirectly) the old x86 way of doing things, but in
the meantime that original x86 model has been improved to hold the VM
semaphore for shorter times etc and to handle VM_FAULT_RETRY and other
"newer" things, so it would be a good idea to bring all those
improvements to the generic case and teach other architectures about
them too.

Reported-and-tested-by: Takashi Iwai 
Tested-by: Jan Engelhardt 
Acked-by: Heiko Carstens  # "s390 still compiles and boots"
Cc: linux-arch@vger.kernel.org
Signed-off-by: Linus Torvalds 
[shengyong: Backport to 3.10
 - adjust context
 - ignore modification for arch nios2, because 3.10 does not support it
 - ignore modification for driver lustre, because 3.10 does not support it
 - ignore VM_FAULT_FALLBACK in VM_FAULT_ERROR, becase 3.10 does not support
   this flag
 - add SIGSEGV handling to powerpc/cell spu_fault.c, because 3.10 does not
   separate it to copro_fault.c
 - add SIGSEGV handling in mm/memory.c, because 3.10 does not separate it
   to gup.c
]
Signed-off-by: Sheng Yong 
Signed-off-by: Greg Kroah-Hartman

arch: mm: pass userspace fault flag to generic fault handler

2014-11-21T17:22:56+00:00

commit 759496ba6407c6994d6a5ce3a5e74937d7816208 upstream.

Unlike global OOM handling, memory cgroup code will invoke the OOM killer
in any OOM situation because it has no way of telling faults occuring in
kernel context - which could be handled more gracefully - from
user-triggered faults.

Pass a flag that identifies faults originating in user space from the
architecture-specific fault handlers to generic code so that memcg OOM
handling can be improved.

Signed-off-by: Johannes Weiner 
Reviewed-by: Michal Hocko 
Cc: David Rientjes 
Cc: KAMEZAWA Hiroyuki 
Cc: azurIt 
Cc: KOSAKI Motohiro 
Signed-off-by: Andrew Morton 
Signed-off-by: Cong Wang 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

mm: invoke oom-killer from remaining unconverted page fault handlers

2014-11-21T17:22:55+00:00

commit 609838cfed972d49a65aac7923a9ff5cbe482e30 upstream.

A few remaining architectures directly kill the page faulting task in an
out of memory situation.  This is usually not a good idea since that
task might not even use a significant amount of memory and so may not be
the optimal victim to resolve the situation.

Since 2.6.29's 1c0fe6e ("mm: invoke oom-killer from page fault") there
is a hook that architecture page fault handlers are supposed to call to
invoke the OOM killer and let it pick the right task to kill.  Convert
the remaining architectures over to this hook.

To have the previous behavior of simply taking out the faulting task the
vm.oom_kill_allocating_task sysctl can be set to 1.

Signed-off-by: Johannes Weiner 
Reviewed-by: Michal Hocko 
Cc: KAMEZAWA Hiroyuki 
Acked-by: David Rientjes 
Acked-by: Vineet Gupta    [arch/arc bits]
Cc: James Hogan 
Cc: David Howells 
Cc: Jonas Bonn 
Cc: Chen Liqin 
Cc: Lennox Wu 
Cc: Chris Metcalf 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Cong Wang 
Signed-off-by: Greg Kroah-Hartman

mn10300: Use early_param() to parse "mem=" parameter

2013-06-28T15:53:03+00:00

This fixes the problem that "init=" options may not be passed to kernel
correctly.

parse_mem_cmdline() of mn10300 arch gets rid of "mem=" string from
redboot_command_line. Then init_setup() parses the "init=" options from
static_command_line, which is a copy of redboot_command_line, and keeps
the pointer to the init options in execute_command variable.

Since the commit 026cee0 upstream (params: _initcall-like kernel
parameters), static_command_line becomes overwritten by saved_command_line at
do_initcall_level(). Notice that saved_command_line is a command line
which includes "mem=" string.

As a result, execute_command may point to weird string by the length of
"mem=" parameter.
I noticed this problem when using the command line like this:

    mem=128M console=ttyS0,115200 init=/bin/sh

Here is the processing flow of command line parameters.
    start_kernel()
      setup_arch(&command_line)
         parse_mem_cmdline(cmdline_p)
           * strcpy(boot_command_line, redboot_command_line);
           * Remove "mem=xxx" from redboot_command_line.
           * *cmdline_p = redboot_command_line;
      setup_command_line(command_line) <-- command_line is redboot_command_line
        * strcpy(saved_command_line, boot_command_line)
        * strcpy(static_command_line, command_line)
      parse_early_param()
        strlcpy(tmp_cmdline, boot_command_line, COMMAND_LINE_SIZE);
        parse_early_options(tmp_cmdline);
          parse_args("early options", cmdline, NULL, 0, 0, 0, do_early_param);
      parse_args("Booting ..", static_command_line, ...);
        init_setup() <-- save the pointer in execute_command
      rest_init()
        kernel_thread(kernel_init, NULL, CLONE_FS | CLONE_SIGHAND);

At this point, execute_command points to "/bin/sh" string.

    kernel_init()
      kernel_init_freeable()
        do_basic_setup()
          do_initcalls()
            do_initcall_level()
              (*) strcpy(static_command_line, saved_command_line);

Here, execute_command gets to point to "200" string !!

Signed-off-by: David Howells

mn10300: Allow to pass array name to get_user()

2013-06-28T15:53:01+00:00

This fixes the following compile error:

CC block/scsi_ioctl.o
block/scsi_ioctl.c: In function 'sg_scsi_ioctl':
block/scsi_ioctl.c:449: error: invalid initializer

Signed-off-by: David Howells

mn10300: Fix include dependency in irqflags.h et al.

2013-06-19T16:29:54+00:00

We need to pick up the definition of raw_smp_processor_id() from
asm/smp.h.  For the !SMP case, we need to supply a definition of
raw_smp_processor_id().

Because of the include dependencies we cannot use smp_call_func_t in
asm/smp.h, but we do need linux/thread_info.h

Signed-off-by: David Daney 
Acked-by: Geert Uytterhoeven 
Acked-by: David Howells 
Signed-off-by: Linus Torvalds

MN10300: Need pci_iomap() and __pci_ioport_map() defining

2013-05-30T04:38:48+00:00

Include the generic definitions of pci_iomap() and __pci_ioport_map()
otherwise we can get errors like:

  lib/pci_iomap.c: In function 'pci_iomap':
  lib/pci_iomap.c:37: error: implicit declaration of function '__pci_ioport_map'
  lib/pci_iomap.c:37: warning: return makes pointer from integer without a cast

and:

  drivers/pci/quirks.c: In function 'disable_igfx_irq':
  drivers/pci/quirks.c:2893: error: implicit declaration of function 'pci_iomap'
  drivers/pci/quirks.c:2893: warning: initialization makes pointer from integer without a cast
  drivers/pci/quirks.c: In function 'reset_ivb_igd':
  drivers/pci/quirks.c:3133: warning: assignment makes pointer from integer without a cast

Signed-off-by: David Howells 
Acked-by: Ken Cox 
Signed-off-by: Linus Torvalds

MN10300: ASB2305's PCI code needs the definition of XIRQ1

2013-05-30T04:38:48+00:00

The code for PCI in the ASB2305 needs the definition of XIRQ1 from proc/irq.h
otherwise the following error appears:

  arch/mn10300/unit-asb2305/pci.c: In function 'unit_pci_init':
  arch/mn10300/unit-asb2305/pci.c:481: error: 'XIRQ1' undeclared (first use in this function)
  arch/mn10300/unit-asb2305/pci.c:481: error: (Each undeclared identifier is reported only once
  arch/mn10300/unit-asb2305/pci.c:481: error: for each function it appears in.)

Signed-off-by: David Howells 
Acked-by: Ken Cox 
Signed-off-by: Linus Torvalds

MN10300: Enable IRQs more in system call exit work path

2013-05-30T04:38:48+00:00

Enable IRQs when calling schedule() for TIF_NEED_RESCHED and
do_notify_resume().  If interrupts are enabled during do_notify_resume(), a
warning can be seen (see lower down).

Whilst we're at it, resume_userspace can be made local to entry.S as it is not
called outside of there and it can be merged with the part of work_resched that
occurs after schedule() is called.

  WARNING: at kernel/softirq.c:160 local_bh_enable+0x42/0xa0()
  Call Trace:
    local_bh_enable+0x42/0xa0
    unix_release_sock+0x86/0x23c
    unix_release+0x20/0x28
    sock_release+0x17/0x88
    sock_close+0x20/0x28
    __fput+0xc9/0x1fc
    ____fput+0xb/0x10
    task_work_run+0x64/0x78
    do_notify_resume+0x53d/0x544
    work_notifysig+0xa/0xc

Signed-off-by: David Howells 
Acked-by: Ken Cox 
Signed-off-by: Linus Torvalds

MN10300: Fix ret_from_kernel_thread

2013-05-30T04:38:48+00:00

ret_from_kernel_thread needs to set A2 to the thread_info pointer before
jumping to syscall_exit.

Without this, we never correctly start userspace.

This was caused by the rejuggling of the fork/exec paths in commit
ddf23e87a804 ("mn10300: switch to saner kernel_execve() semantics")

Reported-by: Ken Cox 
Signed-off-by: David Howells 
Acked-by: Ken Cox 
Acked-by: Al Viro 
Signed-off-by: Linus Torvalds