linux-toradex.git/arch/mips, branch v3.7.8

Revert "MIPS: Optimise TLB handlers for MIPS32/64 R2 cores."

2013-01-17T16:46:43+00:00

commit 9120963578320532dfb3a9a7947e8d05b39900b5 upstream.

This reverts commit ff401e52100dcdc85e572d1ad376d3307b3fe28e.

This breaks on MIPS64 R2 cores such as Broadcom's.

Signed-off-by: Jayachandran C 
Signed-off-by: Greg Kroah-Hartman

MIPS: Fix poweroff failure when HOTPLUG_CPU configured.

2013-01-17T16:45:54+00:00

commit 8add1ecb81f541ef2fcb0b85a5470ad9ecfb4a84 upstream.

When poweroff machine, kernel_power_off() call disable_nonboot_cpus().
And if we have HOTPLUG_CPU configured, disable_nonboot_cpus() is not an
empty function but attempt to actually disable the nonboot cpus. Since
system state is SYSTEM_POWER_OFF, play_dead() won't be called and thus
disable_nonboot_cpus() hangs. Therefore, we make this patch to avoid
poweroff failure.

Signed-off-by: Huacai Chen 
Signed-off-by: Hongliang Tao 
Signed-off-by: Hua Yan 
Cc: Yong Zhang 
Cc: Fuxin Zhang 
Cc: Zhangjin Wu 
Patchwork: https://patchwork.linux-mips.org/patch/4211/
Signed-off-by: Ralf Baechle 
Signed-off-by: Greg Kroah-Hartman

MIPS: Fix endless loop when processing signals for kernel tasks

2012-12-05T18:59:00+00:00

The problem occurs [1] when a kernel-mode task returns from a system
call with a pending signal.

A real-life scenario is a child of 'khelper' returning from a failed
kernel_execve() in ____call_usermodehelper() [ kernel/kmod.c ].
kernel_execve() fails due to a pending SIGKILL, which is the result of
"kill -9 -1" (at least, busybox's init does it upon reboot).

The loop is as follows:

* syscall_exit_work:
 - work_pending:            // start_of_the_loop
 - work_notifysig:
   - do_notify_resume()
     - do_signal()
       - if (!user_mode(regs)) return;
 - resume_userspace         // TIF_SIGPENDING is still set
 - work_pending             // so we call work_pending => goto
                            // start_of_the_loop

More information can be found in another LKML thread:
http://www.serverphorums.com/read.php?12,457826

[1] The problem was also reproduced on !CONFIG_VM86 x86, and the
following fix was accepted.

http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=29a2e2836ff9ea65a603c89df217f4198973a74f

Signed-off-by: Dmitry Adamushko 
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/3571/
Signed-off-by: Ralf Baechle

MIPS: R3000/R3081: Fix CPU detection.

2012-12-05T18:58:54+00:00

Broken since e05ea74fc56f347f872ef9946d27c53e8bf20864 (lmo) rsp.
cea7e2dfdef53fe55f359d00da562a268be06fd2 (kernel.org) [MIPS: Sort out CPU
type to name translation.]  These CPUs are no longer very popular to say
the least ...

Signed-off-by: Ralf Baechle 
Reported-by: Murphy McCauley

MIPS: N32: Fix signalfd4 syscall entry point

2012-12-05T18:58:48+00:00

This needs to use the compat entry point or it's going to fail on big
endian systems.

Noticed by Al Viro.

Signed-off-by: Ralf Baechle

MIPS: N32: Fix preadv(2) and pwritev(2) entry points.

2012-12-04T16:59:39+00:00

By using the native syscall entry point the kernel was also expecting
64-bit iovec structures.

This is broken since ddd9e91b71072b8ebe89311c3a44b077defa1756 [preadv/
pwritev: MIPS: Add preadv(2) and pwritev(2) syscalls.] which originally
added these two syscalls.  I walked through piles of code, including
libc and couldn't find anything that would have worked around the issue
so this change the API to what it should always have been.

Noticed and patch suggested by Al Viro.

Signed-off-by: Ralf Baechle

MIPS: Avoid mcheck by flushing page range in huge_ptep_set_access_flags()

2012-12-04T15:57:54+00:00

Problem:

1) Huge page mapping of anonymous memory is initially invalid.  Will be
   faulted in by copy-on-write mechanism.

2) Userspace attempts store at the end of the huge mapping.

3) TLB Refill exception handler fill TLB with a normal (4K sized)
   invalid page at the end of the huge mapping virtual address range.

4) Userspace restarted, and re-attempts the store at the end of the
   huge mapping.

5) Page from #3 is invalid, we get a fault and go to the hugepage
   fault handler.  This tries to map a huge page and calls
   huge_ptep_set_access_flags() to install the mapping.

6) We just call the generic ptep_set_access_flags() to set up the page
   tables, but the flush there assumes a normal (4K sized) page and
   only tries to flush the first part of the huge page virtual address
   out of the TLB, since the existing entry from step #3 doesn't
   conflict, nothing is flushed.

7) We attempt to load the mapping into the TLB, but because it
   conflicts with the entry from step #3, we get a Machine Check
   exception.

The fix: Flush the entire rage covered by the huge page in
huge_ptep_set_access_flags(), and remove the optimization in
local_flush_tlb_range() so that the flush actually does the correct
thing.

Signed-off-by: David Daney 
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Cc: Hillf Danton 
Patchwork: https://patchwork.linux-mips.org/patch/4661/
Signed-off-by: Ralf Baechle 
(cherry picked from commit dd617f258cc39d36be26afee9912624a2d23112c)

MIPS: Fix crash that occurs when function tracing is enabled

2012-11-23T17:44:38+00:00

A recent patch changed some irq routines from inlines to functions.
These routines are called by the tracer code. Now that they're functions,
if they are compiled for function tracing they will call the tracer
and crash the system due to infinite recursion. The fix disables
tracing in these functions by using "notrace" in the function
definition.

Signed-off-by: Al Cooper 
Reviewed-by: David Daney 
Pathchwork: https://patchwork.linux-mips.org/patch/4564/
Signed-off-by: Ralf Baechle

MIPS: Merge overlapping bootmem ranges

2012-11-23T17:44:37+00:00

Without this, we may end up with something like this in /proc/iomem:

01100000-014fffff : System RAM
  01100000-013bf48f : Kernel code
  013bf490-0149e01f : Kernel data
01500000-0c0fffff : System RAM

but the two System RAM ranges should be one single range.  This particular
case will result in kexec failure on Octeon systems if the kernel being
loaded by kexec is bigger than the already running kernel.

Signed-off-by: Ralf Baechle

mips, arc: fix build failure

2012-11-16T22:33:04+00:00

Using a cross-compiler to fix another issue, the following build error
occurred for mips defconfig:

  arch/mips/fw/arc/misc.c: In function 'ArcHalt':
  arch/mips/fw/arc/misc.c:25:2: error: implicit declaration of function 'local_irq_disable'

Fix it up by including irqflags.h.

Signed-off-by: David Rientjes 
Cc: Ralf Baechle 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds