linux-stable.git/arch/mips/include, branch v3.12.52

arch: Introduce smp_load_acquire(), smp_store_release()

2015-08-25T14:56:59+00:00

commit 47933ad41a86a4a9b50bed7c9b9bd2ba242aac63 upstream.

A number of situations currently require the heavyweight smp_mb(),
even though there is no need to order prior stores against later
loads.  Many architectures have much cheaper ways to handle these
situations, but the Linux kernel currently has no portable way
to make use of them.

This commit therefore supplies smp_load_acquire() and
smp_store_release() to remedy this situation.  The new
smp_load_acquire() primitive orders the specified load against
any subsequent reads or writes, while the new smp_store_release()
primitive orders the specifed store against any prior reads or
writes.  These primitives allow array-based circular FIFOs to be
implemented without an smp_mb(), and also allow a theoretical
hole in rcu_assign_pointer() to be closed at no additional
expense on most architectures.

In addition, the RCU experience transitioning from explicit
smp_read_barrier_depends() and smp_wmb() to rcu_dereference()
and rcu_assign_pointer(), respectively resulted in substantial
improvements in readability.  It therefore seems likely that
replacing other explicit barriers with smp_load_acquire() and
smp_store_release() will provide similar benefits.  It appears
that roughly half of the explicit barriers in core kernel code
might be so replaced.

[Changelog by PaulMck]

Reviewed-by: "Paul E. McKenney" 
Signed-off-by: Peter Zijlstra 
Acked-by: Will Deacon 
Cc: Benjamin Herrenschmidt 
Cc: Frederic Weisbecker 
Cc: Mathieu Desnoyers 
Cc: Michael Ellerman 
Cc: Michael Neuling 
Cc: Russell King 
Cc: Geert Uytterhoeven 
Cc: Heiko Carstens 
Cc: Linus Torvalds 
Cc: Martin Schwidefsky 
Cc: Victor Kaplansky 
Cc: Tony Luck 
Cc: Oleg Nesterov 
Link: http://lkml.kernel.org/r/20131213150640.908486364@infradead.org
Signed-off-by: Ingo Molnar 
Signed-off-by: Jiri Slaby

MIPS: Make set_pte() SMP safe.

2015-08-19T06:36:46+00:00

commit 46011e6ea39235e4aca656673c500eac81a07a17 upstream.

On MIPS the GLOBAL bit of the PTE must have the same value in any
aligned pair of PTEs.  These pairs of PTEs are referred to as
"buddies".  In a SMP system is is possible for two CPUs to be calling
set_pte() on adjacent PTEs at the same time.  There is a race between
setting the PTE and a different CPU setting the GLOBAL bit in its
buddy PTE.

This race can be observed when multiple CPUs are executing
vmap()/vfree() at the same time.

Make setting the buddy PTE's GLOBAL bit an atomic operation to close
the race condition.

The case of CONFIG_64BIT_PHYS_ADDR && CONFIG_CPU_MIPS32 is *not*
handled.

Signed-off-by: David Daney 
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/10835/
Signed-off-by: Ralf Baechle 
Signed-off-by: Jiri Slaby

MIPS: Fix KVM guest fixmap address

2015-07-30T12:10:42+00:00

commit 8e748c8d09a9314eedb5c6367d9acfaacddcdc88 upstream.

KVM guest kernels for trap & emulate run in user mode, with a modified
set of kernel memory segments. However the fixmap address is still in
the normal KSeg3 region at 0xfffe0000 regardless, causing problems when
cache alias handling makes use of them when handling copy on write.

Therefore define FIXADDR_TOP as 0x7ffe0000 in the guest kernel mapped
region when CONFIG_KVM_GUEST is defined.

Signed-off-by: James Hogan 
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/9887/
Signed-off-by: Ralf Baechle 
Signed-off-by: Jiri Slaby

nosave: consolidate __nosave_{begin,end} in

2015-05-04T09:49:04+00:00

commit 7f8998c7aef3ac9c5f3f2943e083dfa6302e90d0 upstream.

The different architectures used their own (and different) declarations:

    extern __visible const void __nosave_begin, __nosave_end;
    extern const void __nosave_begin, __nosave_end;
    extern long __nosave_begin, __nosave_end;

Consolidate them using the first variant in .

Signed-off-by: Geert Uytterhoeven 
Cc: Russell King 
Cc: Ralf Baechle 
Cc: Benjamin Herrenschmidt 
Cc: Martin Schwidefsky 
Cc: "David S. Miller" 
Cc: Guan Xuetao 
Cc: Thomas Gleixner 
Cc: Ingo Molnar 
Cc: "H. Peter Anvin" 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Jiri Slaby 
[js -- port to 3.12: arm does not have hibernation yet]

MIPS: asm/reg.h: Make 32- and 64-bit definitions available at the same time

2015-04-09T12:13:32+00:00

commit bcec7c8da6b092b1ff3327fd83c2193adb12f684 upstream.

Get rid of the WANT_COMPAT_REG_H test and instead define both the 32-
and 64-bit register offset definitions at the same time with
MIPS{32,64}_ prefixes, then define the existing EF_* names to the
correct definitions for the kernel's bitness.

This patch is a prerequisite of the following bug fix patch.

Signed-off-by: Alex Smith 
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/7451/
Signed-off-by: Ralf Baechle 
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Jiri Slaby

MIPS: ftrace: Fix a microMIPS build problem

2014-11-13T18:02:31+00:00

commit aedd153f5bb5b1f1d6d9142014f521ae2ec294cc upstream.

Code before the .fixup section needs to have the .insn directive.
This has no side effects on MIPS32/64 but it affects the way microMIPS
loads the address for the return label.

Fixes the following build problem:
mips-linux-gnu-ld: arch/mips/built-in.o: .fixup+0x4a0: Unsupported jump between
ISA modes; consider recompiling with interlinking enabled.
mips-linux-gnu-ld: final link failed: Bad value
Makefile:819: recipe for target 'vmlinux' failed

The fix is similar to 1658f914ff91c3bf ("MIPS: microMIPS:
Disable LL/SC and fix linker bug.")

Signed-off-by: Markos Chandras 
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/8117/
Signed-off-by: Ralf Baechle 
Signed-off-by: Jiri Slaby

MIPS: asm: thread_info: Add _TIF_SECCOMP flag

2014-06-18T15:28:08+00:00

commit 137f7df8cead00688524c82360930845396b8a21 upstream.

Add _TIF_SECCOMP flag to _TIF_WORK_SYSCALL_ENTRY to indicate
that the system call needs to be checked against a seccomp filter.

Signed-off-by: Markos Chandras 
Reviewed-by: Paul Burton 
Reviewed-by: James Hogan 
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6405/
Signed-off-by: Ralf Baechle 
Signed-off-by: Jiri Slaby

MIPS: include linux/types.h

2014-03-24T08:45:06+00:00

commit 87c99203fea897fbdd84b681ad9fced2517dcf98 upstream.

The file uses u16 type but doesn't include its definition explicitly

I was getting this error when including this header in my driver:

  arch/mips/include/asm/mipsregs.h:644:33: error: unknown type name ‘u16’

Signed-off-by: Qais Yousef 
Reviewed-by: Steven J. Hill 
Acked-by: David Daney 
Signed-off-by: John Crispin 
Patchwork: http://patchwork.linux-mips.org/patch/6212/
Signed-off-by: Jiri Slaby

compiler/gcc4: Add quirk for 'asm goto' miscompilation bug

2013-10-11T05:39:14+00:00

Fengguang Wu, Oleg Nesterov and Peter Zijlstra tracked down
a kernel crash to a GCC bug: GCC miscompiles certain 'asm goto'
constructs, as outlined here:

  http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58670

Implement a workaround suggested by Jakub Jelinek.

Reported-and-tested-by: Fengguang Wu 
Reported-by: Oleg Nesterov 
Reported-by: Peter Zijlstra 
Suggested-by: Jakub Jelinek 
Reviewed-by: Richard Henderson 
Cc: Linus Torvalds 
Cc: Andrew Morton 
Cc: 
Signed-off-by: Ingo Molnar

MIPS: cpu-features.h: s/MIPS53/MIPS64/

2013-09-24T09:07:18+00:00

No support for MIPS53 processors yet.

Signed-off-by: Maciej W. Rozycki 
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/5876/
Signed-off-by: Ralf Baechle