linux-stable.git/arch/mips/kernel, branch v3.2.97

MIPS: Refactor 'clear_page' and 'copy_page' functions.

2017-10-12T14:27:21+00:00

commit c022630633624a75b3b58f43dd3c6cc896a56cff upstream.

Remove usage of the '__attribute__((alias("...")))' hack that aliased
to integer arrays containing micro-assembled instructions. This hack
breaks when building a microMIPS kernel. It also makes the code much
easier to understand.

[ralf@linux-mips.org: Added back export of the clear_page and copy_page
symbols so certain modules will work again.  Also fixed build with
CONFIG_SIBYTE_DMA_PAGEOPS enabled.]

Signed-off-by: Steven J. Hill 
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/3866/
Acked-by: David Daney 
Signed-off-by: Ralf Baechle 
[bwh: Backported to 3.2: adjust context]
Cc: Guenter Roeck 
Signed-off-by: Ben Hutchings

MIPS: Send SIGILL for BPOSGE32 in `__compute_return_epc_for_insn'

2017-10-12T14:27:12+00:00

commit 7b82c1058ac1f8f8b9f2b8786b1f710a57a870a8 upstream.

Fix commit e50c0a8fa60d ("Support the MIPS32 / MIPS64 DSP ASE.") and
send SIGILL rather than SIGBUS whenever an unimplemented BPOSGE32 DSP
ASE instruction has been encountered in `__compute_return_epc_for_insn'
as our Reserved Instruction exception handler would in response to an
attempt to actually execute the instruction.  Sending SIGBUS only makes
sense for the unaligned PC case, since moved to `__compute_return_epc'.
Adjust function documentation accordingly, correct formatting and use
`pr_info' rather than `printk' as the other exit path already does.

Fixes: e50c0a8fa60d ("Support the MIPS32 / MIPS64 DSP ASE.")
Signed-off-by: Maciej W. Rozycki 
Cc: James Hogan 
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/16396/
Signed-off-by: Ralf Baechle 
[bwh: Backported to 3.2:
 - Drop the comment change
 - Adjust context]
Signed-off-by: Ben Hutchings

MIPS: Fix mips_atomic_set() retry condition

2017-10-12T14:27:11+00:00

commit 2ec420b26f7b6ff332393f0bb5a7d245f7ad87f0 upstream.

The inline asm retry check in the MIPS_ATOMIC_SET operation of the
sysmips system call has been backwards since commit f1e39a4a616c ("MIPS:
Rewrite sysmips(MIPS_ATOMIC_SET, ...) in C with inline assembler")
merged in v2.6.32, resulting in the non R10000_LLSC_WAR case retrying
until the operation was inatomic, before returning the new value that
was probably just written multiple times instead of the old value.

Invert the branch condition to fix that particular issue.

Fixes: f1e39a4a616c ("MIPS: Rewrite sysmips(MIPS_ATOMIC_SET, ...) in C with inline assembler")
Signed-off-by: James Hogan 
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/16148/
Signed-off-by: Ralf Baechle 
Signed-off-by: Ben Hutchings

MIPS: Fix IRQ tracing & lockdep when rescheduling

2017-09-15T17:30:56+00:00

commit d8550860d910c6b7b70f830f59003b33daaa52c9 upstream.

When the scheduler sets TIF_NEED_RESCHED & we call into the scheduler
from arch/mips/kernel/entry.S we disable interrupts. This is true
regardless of whether we reach work_resched from syscall_exit_work,
resume_userspace or by looping after calling schedule(). Although we
disable interrupts in these paths we don't call trace_hardirqs_off()
before calling into C code which may acquire locks, and we therefore
leave lockdep with an inconsistent view of whether interrupts are
disabled or not when CONFIG_PROVE_LOCKING & CONFIG_DEBUG_LOCKDEP are
both enabled.

Without tracing this interrupt state lockdep will print warnings such
as the following once a task returns from a syscall via
syscall_exit_partial with TIF_NEED_RESCHED set:

[   49.927678] ------------[ cut here ]------------
[   49.934445] WARNING: CPU: 0 PID: 1 at kernel/locking/lockdep.c:3687 check_flags.part.41+0x1dc/0x1e8
[   49.946031] DEBUG_LOCKS_WARN_ON(current->hardirqs_enabled)
[   49.946355] CPU: 0 PID: 1 Comm: init Not tainted 4.10.0-00439-gc9fd5d362289-dirty #197
[   49.963505] Stack : 0000000000000000 ffffffff81bb5d6a 0000000000000006 ffffffff801ce9c4
[   49.974431]         0000000000000000 0000000000000000 0000000000000000 000000000000004a
[   49.985300]         ffffffff80b7e487 ffffffff80a24498 a8000000ff160000 ffffffff80ede8b8
[   49.996194]         0000000000000001 0000000000000000 0000000000000000 0000000077c8030c
[   50.007063]         000000007fd8a510 ffffffff801cd45c 0000000000000000 a8000000ff127c88
[   50.017945]         0000000000000000 ffffffff801cf928 0000000000000001 ffffffff80a24498
[   50.028827]         0000000000000000 0000000000000001 0000000000000000 0000000000000000
[   50.039688]         0000000000000000 a8000000ff127bd0 0000000000000000 ffffffff805509bc
[   50.050575]         00000000140084e0 0000000000000000 0000000000000000 0000000000040a00
[   50.061448]         0000000000000000 ffffffff8010e1b0 0000000000000000 ffffffff805509bc
[   50.072327]         ...
[   50.076087] Call Trace:
[   50.079869] [] show_stack+0x80/0xa8
[   50.086577] [] dump_stack+0x10c/0x190
[   50.093498] [] __warn+0xf0/0x108
[   50.099889] [] warn_slowpath_fmt+0x3c/0x48
[   50.107241] [] check_flags.part.41+0x1dc/0x1e8
[   50.114961] [] lock_is_held_type+0x8c/0xb0
[   50.122291] [] __schedule+0x8c0/0x10f8
[   50.129221] [] schedule+0x30/0x98
[   50.135659] [] work_resched+0x8/0x34
[   50.142397] ---[ end trace 0cb4f6ef5b99fe21 ]---
[   50.148405] possible reason: unannotated irqs-off.
[   50.154600] irq event stamp: 400463
[   50.159566] hardirqs last  enabled at (400463): [] _raw_spin_unlock_irqrestore+0x40/0xa8
[   50.171981] hardirqs last disabled at (400462): [] _raw_spin_lock_irqsave+0x30/0xb0
[   50.183897] softirqs last  enabled at (400450): [] __do_softirq+0x4ac/0x6a8
[   50.195015] softirqs last disabled at (400425): [] irq_exit+0x110/0x128

Fix this by using the TRACE_IRQS_OFF macro to call trace_hardirqs_off()
when CONFIG_TRACE_IRQFLAGS is enabled. This is done before invoking
schedule() following the work_resched label because:

 1) Interrupts are disabled regardless of the path we take to reach
    work_resched() & schedule().

 2) Performing the tracing here avoids the need to do it in paths which
    disable interrupts but don't call out to C code before hitting a
    path which uses the RESTORE_SOME macro that will call
    trace_hardirqs_on() or trace_hardirqs_off() as appropriate.

We call trace_hardirqs_on() using the TRACE_IRQS_ON macro before calling
syscall_trace_leave() for similar reasons, ensuring that lockdep has a
consistent view of state after we re-enable interrupts.

Signed-off-by: Paul Burton 
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/15385/
Signed-off-by: Ralf Baechle 
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings

MIPS: KGDB: Use kernel context for sleeping threads

2017-07-18T17:38:42+00:00

commit 162b270c664dca2e0944308e92f9fcc887151a72 upstream.

KGDB is a kernel debug stub and it can't be used to debug userland as it
can only safely access kernel memory.

On MIPS however KGDB has always got the register state of sleeping
processes from the userland register context at the beginning of the
kernel stack. This is meaningless for kernel threads (which never enter
userland), and for user threads it prevents the user seeing what it is
doing while in the kernel:

(gdb) info threads
  Id   Target Id         Frame
  ...
  3    Thread 2 (kthreadd) 0x0000000000000000 in ?? ()
  2    Thread 1 (init)   0x000000007705c4b4 in ?? ()
  1    Thread -2 (shadowCPU0) 0xffffffff8012524c in arch_kgdb_breakpoint () at arch/mips/kernel/kgdb.c:201

Get the register state instead from the (partial) kernel register
context stored in the task's thread_struct for resume() to restore. All
threads now correctly appear to be in context_switch():

(gdb) info threads
  Id   Target Id         Frame
  ...
  3    Thread 2 (kthreadd) context_switch (rq=, cookie=..., next=, prev=0x0) at kernel/sched/core.c:2903
  2    Thread 1 (init)   context_switch (rq=, cookie=..., next=, prev=0x0) at kernel/sched/core.c:2903
  1    Thread -2 (shadowCPU0) 0xffffffff8012524c in arch_kgdb_breakpoint () at arch/mips/kernel/kgdb.c:201

Call clobbered registers which aren't saved and exception registers
(BadVAddr & Cause) which can't be easily determined without stack
unwinding are reported as 0. The PC is taken from the return address,
such that the state presented matches that found immediately after
returning from resume().

Fixes: 8854700115ec ("[MIPS] kgdb: add arch support for the kernel's kgdb core")
Signed-off-by: James Hogan 
Cc: Jason Wessel 
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/15829/
Signed-off-by: Ralf Baechle 
Signed-off-by: Ben Hutchings

KEYS: 64-bit MIPS needs to use compat_sys_keyctl for 32-bit userspace

2016-11-20T01:01:29+00:00

commit 20f06ed9f61a185c6dabd662c310bed6189470df upstream.

MIPS64 needs to use compat_sys_keyctl for 32-bit userspace rather than
calling sys_keyctl.  The latter will work in a lot of cases, thereby hiding
the issue.

Reported-by: Stephan Mueller 
Signed-off-by: David Howells 
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-security-module@vger.kernel.org
Cc: keyrings@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/13832/
Signed-off-by: Ralf Baechle 
Signed-off-by: Ben Hutchings

MIPS: traps: Fix SIGFPE information leak from `do_ov' and `do_trap_or_bp'

2016-04-01T00:54:37+00:00

commit e723e3f7f9591b79e8c56b3d7c5a204a9c571b55 upstream.

Avoid sending a partially initialised `siginfo_t' structure along SIGFPE
signals issued from `do_ov' and `do_trap_or_bp', leading to information
leaking from the kernel stack.

Signed-off-by: Maciej W. Rozycki 
Signed-off-by: Ralf Baechle 
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings

MIPS: Fix restart of indirect syscalls

2016-01-22T21:40:08+00:00

commit e967ef022e00bb7c2e5b1a42007abfdd52055050 upstream.

When 32-bit MIPS userspace invokes a syscall indirectly via syscall(number,
arg1, ..., arg7), the kernel looks up the actual syscall based on the given
number, shifts the other arguments to the left, and jumps to the syscall.

If the syscall is interrupted by a signal and indicates it needs to be
restarted by the kernel (by returning ERESTARTNOINTR for example), the
syscall must be called directly, since the number is no longer the first
argument, and the other arguments are now staged for a direct call.

Before shifting the arguments, store the syscall number in pt_regs->regs[2].
This gets copied temporarily into pt_regs->regs[0] after the syscall returns.
If the syscall needs to be restarted, handle_signal()/do_signal() copies the
number back to pt_regs->reg[2], which ends up in $v0 once control returns to
userspace.

Signed-off-by: Ed Swierk 
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/8929/
Signed-off-by: Ralf Baechle 
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings

MIPS: Fix sched_getaffinity with MT FPAFF enabled

2015-10-13T02:46:01+00:00

commit 1d62d737555e1378eb62a8bba26644f7d97139d2 upstream.

p->thread.user_cpus_allowed is zero-initialized and is only filled on
the first sched_setaffinity call.

To avoid adding overhead in the task initialization codepath, simply OR
the returned mask in sched_getaffinity with p->cpus_allowed.

Signed-off-by: Felix Fietkau 
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/10740/
Signed-off-by: Ralf Baechle 
[bwh: Backported to 3.2: also convert from obsolete cpumask API]
Signed-off-by: Ben Hutchings

MIPS: Fix enabling of DEBUG_STACKOVERFLOW

2015-08-06T23:32:15+00:00

commit 5f35b9cd553fd64415b563497d05a563c988dbd6 upstream.

Commit 334c86c494b9 ("MIPS: IRQ: Add stackoverflow detection") added
kernel stack overflow detection, however it only enabled it conditional
upon the preprocessor definition DEBUG_STACKOVERFLOW, which is never
actually defined. The Kconfig option is called DEBUG_STACKOVERFLOW,
which manifests to the preprocessor as CONFIG_DEBUG_STACKOVERFLOW, so
switch it to using that definition instead.

Fixes: 334c86c494b9 ("MIPS: IRQ: Add stackoverflow detection")
Signed-off-by: James Hogan 
Cc: Ralf Baechle 
Cc: Adam Jiang 
Cc: linux-mips@linux-mips.org
Patchwork: http://patchwork.linux-mips.org/patch/10531/
Signed-off-by: Ralf Baechle 
Signed-off-by: Ben Hutchings