ARM: 8115/1: LPAE: reduce damage caused by idmap to virtual memory layout

commit 811a2407a3cf7bbd027fbe92d73416f17485a3d8 upstream.

On LPAE, each level 1 (pgd) page table entry maps 1GiB, and the level 2
(pmd) entries map 2MiB.

When the identity mapping is created on LPAE, the pgd pointers are copied
from the swapper_pg_dir.  If we find that we need to modify the contents
of a pmd, we allocate a new empty pmd table and insert it into the
appropriate 1GB slot, before then filling it with the identity mapping.

However, if the 1GB slot covers the kernel lowmem mappings, we obliterate
those mappings.

When replacing a PMD, first copy the old PMD contents to the new PMD, so
that we preserve the existing mappings, particularly the mappings of the
kernel itself.

[rewrote commit message and added code comment -- rmk]

Fixes: ae2de101739c ("ARM: LPAE: Add identity mapping support for the 3-level page table format")
Signed-off-by: Konstantin Khlebnikov <k.khlebnikov@samsung.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
printk: rename printk_sched to printk_deferred

commit aac74dc495456412c4130a1167ce4beb6c1f0b38 upstream.

After learning we'll need some sort of deferred printk functionality in
the timekeeping core, Peter suggested we rename the printk_sched function
so it can be reused by needed subsystems.

This only changes the function name. No logic changes.

Signed-off-by: John Stultz <john.stultz@linaro.org>
Reviewed-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Jiri Bohac <jbohac@suse.cz>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
timer: Fix lock inversion between hrtimer_bases.lock and scheduler locks

commit 504d58745c9ca28d33572e2d8a9990b43e06075d upstream.

clockevents_increase_min_delta() calls printk() from under
hrtimer_bases.lock. That causes lock inversion on scheduler locks because
printk() can call into the scheduler. Lockdep puts it as:

======================================================
[ INFO: possible circular locking dependency detected ]
3.15.0-rc8-06195-g939f04b #2 Not tainted
-------------------------------------------------------
trinity-main/74 is trying to acquire lock:
 (&port_lock_key){-.....}, at: [<811c60be>] serial8250_console_write+0x8c/0x10c

but task is already holding lock:
 (hrtimer_bases.lock){-.-...}, at: [<8103caeb>] hrtimer_try_to_cancel+0x13/0x66

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-> #5 (hrtimer_bases.lock){-.-...}:
       [<8104a942>] lock_acquire+0x92/0x101
       [<8142f11d>] _raw_spin_lock_irqsave+0x2e/0x3e
       [<8103c918>] __hrtimer_start_range_ns+0x1c/0x197
       [<8107ec20>] perf_swevent_start_hrtimer.part.41+0x7a/0x85
       [<81080792>] task_clock_event_start+0x3a/0x3f
       [<810807a4>] task_clock_event_add+0xd/0x14
       [<8108259a>] event_sched_in+0xb6/0x17a
       [<810826a2>] group_sched_in+0x44/0x122
       [<81082885>] ctx_sched_in.isra.67+0x105/0x11f
       [<810828e6>] perf_event_sched_in.isra.70+0x47/0x4b
       [<81082bf6>] __perf_install_in_context+0x8b/0xa3
       [<8107eb8e>] remote_function+0x12/0x2a
       [<8105f5af>] smp_call_function_single+0x2d/0x53
       [<8107e17d>] task_function_call+0x30/0x36
       [<8107fb82>] perf_install_in_context+0x87/0xbb
       [<810852c9>] SYSC_perf_event_open+0x5c6/0x701
       [<810856f9>] SyS_perf_event_open+0x17/0x19
       [<8142f8ee>] syscall_call+0x7/0xb

-> #4 (&ctx->lock){......}:
       [<8104a942>] lock_acquire+0x92/0x101
       [<8142f04c>] _raw_spin_lock+0x21/0x30
       [<81081df3>] __perf_event_task_sched_out+0x1dc/0x34f
       [<8142cacc>] __schedule+0x4c6/0x4cb
       [<8142cae0>] schedule+0xf/0x11
       [<8142f9a6>] work_resched+0x5/0x30

-> #3 (&rq->lock){-.-.-.}:
       [<8104a942>] lock_acquire+0x92/0x101
       [<8142f04c>] _raw_spin_lock+0x21/0x30
       [<81040873>] __task_rq_lock+0x33/0x3a
       [<8104184c>] wake_up_new_task+0x25/0xc2
       [<8102474b>] do_fork+0x15c/0x2a0
       [<810248a9>] kernel_thread+0x1a/0x1f
       [<814232a2>] rest_init+0x1a/0x10e
       [<817af949>] start_kernel+0x303/0x308
       [<817af2ab>] i386_start_kernel+0x79/0x7d

-> #2 (&p->pi_lock){-.-...}:
       [<8104a942>] lock_acquire+0x92/0x101
       [<8142f11d>] _raw_spin_lock_irqsave+0x2e/0x3e
       [<810413dd>] try_to_wake_up+0x1d/0xd6
       [<810414cd>] default_wake_function+0xb/0xd
       [<810461f3>] __wake_up_common+0x39/0x59
       [<81046346>] __wake_up+0x29/0x3b
       [<811b8733>] tty_wakeup+0x49/0x51
       [<811c3568>] uart_write_wakeup+0x17/0x19
       [<811c5dc1>] serial8250_tx_chars+0xbc/0xfb
       [<811c5f28>] serial8250_handle_irq+0x54/0x6a
       [<811c5f57>] serial8250_default_handle_irq+0x19/0x1c
       [<811c56d8>] serial8250_interrupt+0x38/0x9e
       [<810510e7>] handle_irq_event_percpu+0x5f/0x1e2
       [<81051296>] handle_irq_event+0x2c/0x43
       [<81052cee>] handle_level_irq+0x57/0x80
       [<81002a72>] handle_irq+0x46/0x5c
       [<810027df>] do_IRQ+0x32/0x89
       [<8143036e>] common_interrupt+0x2e/0x33
       [<8142f23c>] _raw_spin_unlock_irqrestore+0x3f/0x49
       [<811c25a4>] uart_start+0x2d/0x32
       [<811c2c04>] uart_write+0xc7/0xd6
       [<811bc6f6>] n_tty_write+0xb8/0x35e
       [<811b9beb>] tty_write+0x163/0x1e4
       [<811b9cd9>] redirected_tty_write+0x6d/0x75
       [<810b6ed6>] vfs_write+0x75/0xb0
       [<810b7265>] SyS_write+0x44/0x77
       [<8142f8ee>] syscall_call+0x7/0xb

-> #1 (&tty->write_wait){-.....}:
       [<8104a942>] lock_acquire+0x92/0x101
       [<8142f11d>] _raw_spin_lock_irqsave+0x2e/0x3e
       [<81046332>] __wake_up+0x15/0x3b
       [<811b8733>] tty_wakeup+0x49/0x51
       [<811c3568>] uart_write_wakeup+0x17/0x19
       [<811c5dc1>] serial8250_tx_chars+0xbc/0xfb
       [<811c5f28>] serial8250_handle_irq+0x54/0x6a
       [<811c5f57>] serial8250_default_handle_irq+0x19/0x1c
       [<811c56d8>] serial8250_interrupt+0x38/0x9e
       [<810510e7>] handle_irq_event_percpu+0x5f/0x1e2
       [<81051296>] handle_irq_event+0x2c/0x43
       [<81052cee>] handle_level_irq+0x57/0x80
       [<81002a72>] handle_irq+0x46/0x5c
       [<810027df>] do_IRQ+0x32/0x89
       [<8143036e>] common_interrupt+0x2e/0x33
       [<8142f23c>] _raw_spin_unlock_irqrestore+0x3f/0x49
       [<811c25a4>] uart_start+0x2d/0x32
       [<811c2c04>] uart_write+0xc7/0xd6
       [<811bc6f6>] n_tty_write+0xb8/0x35e
       [<811b9beb>] tty_write+0x163/0x1e4
       [<811b9cd9>] redirected_tty_write+0x6d/0x75
       [<810b6ed6>] vfs_write+0x75/0xb0
       [<810b7265>] SyS_write+0x44/0x77
       [<8142f8ee>] syscall_call+0x7/0xb

-> #0 (&port_lock_key){-.....}:
       [<8104a62d>] __lock_acquire+0x9ea/0xc6d
       [<8104a942>] lock_acquire+0x92/0x101
       [<8142f11d>] _raw_spin_lock_irqsave+0x2e/0x3e
       [<811c60be>] serial8250_console_write+0x8c/0x10c
       [<8104e402>] call_console_drivers.constprop.31+0x87/0x118
       [<8104f5d5>] console_unlock+0x1d7/0x398
       [<8104fb70>] vprintk_emit+0x3da/0x3e4
       [<81425f76>] printk+0x17/0x19
       [<8105bfa0>] clockevents_program_min_delta+0x104/0x116
       [<8105c548>] clockevents_program_event+0xe7/0xf3
       [<8105cc1c>] tick_program_event+0x1e/0x23
       [<8103c43c>] hrtimer_force_reprogram+0x88/0x8f
       [<8103c49e>] __remove_hrtimer+0x5b/0x79
       [<8103cb21>] hrtimer_try_to_cancel+0x49/0x66
       [<8103cb4b>] hrtimer_cancel+0xd/0x18
       [<8107f102>] perf_swevent_cancel_hrtimer.part.60+0x2b/0x30
       [<81080705>] task_clock_event_stop+0x20/0x64
       [<81080756>] task_clock_event_del+0xd/0xf
       [<81081350>] event_sched_out+0xab/0x11e
       [<810813e0>] group_sched_out+0x1d/0x66
       [<81081682>] ctx_sched_out+0xaf/0xbf
       [<81081e04>] __perf_event_task_sched_out+0x1ed/0x34f
       [<8142cacc>] __schedule+0x4c6/0x4cb
       [<8142cae0>] schedule+0xf/0x11
       [<8142f9a6>] work_resched+0x5/0x30

other info that might help us debug this:

Chain exists of:
  &port_lock_key --> &ctx->lock --> hrtimer_bases.lock

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(hrtimer_bases.lock);
                               lock(&ctx->lock);
                               lock(hrtimer_bases.lock);
  lock(&port_lock_key);

 *** DEADLOCK ***

4 locks held by trinity-main/74:
 #0:  (&rq->lock){-.-.-.}, at: [<8142c6f3>] __schedule+0xed/0x4cb
 #1:  (&ctx->lock){......}, at: [<81081df3>] __perf_event_task_sched_out+0x1dc/0x34f
 #2:  (hrtimer_bases.lock){-.-...}, at: [<8103caeb>] hrtimer_try_to_cancel+0x13/0x66
 #3:  (console_lock){+.+...}, at: [<8104fb5d>] vprintk_emit+0x3c7/0x3e4

stack backtrace:
CPU: 0 PID: 74 Comm: trinity-main Not tainted 3.15.0-rc8-06195-g939f04b #2
 00000000 81c3a310 8b995c14 81426f69 8b995c44 81425a99 8161f671 8161f570
 8161f538 8161f559 8161f538 8b995c78 8b142bb0 00000004 8b142fdc 8b142bb0
 8b995ca8 8104a62d 8b142fac 000016f2 81c3a310 00000001 00000001 00000003
Call Trace:
 [<81426f69>] dump_stack+0x16/0x18
 [<81425a99>] print_circular_bug+0x18f/0x19c
 [<8104a62d>] __lock_acquire+0x9ea/0xc6d
 [<8104a942>] lock_acquire+0x92/0x101
 [<811c60be>] ? serial8250_console_write+0x8c/0x10c
 [<811c6032>] ? wait_for_xmitr+0x76/0x76
 [<8142f11d>] _raw_spin_lock_irqsave+0x2e/0x3e
 [<811c60be>] ? serial8250_console_write+0x8c/0x10c
 [<811c60be>] serial8250_console_write+0x8c/0x10c
 [<8104af87>] ? lock_release+0x191/0x223
 [<811c6032>] ? wait_for_xmitr+0x76/0x76
 [<8104e402>] call_console_drivers.constprop.31+0x87/0x118
 [<8104f5d5>] console_unlock+0x1d7/0x398
 [<8104fb70>] vprintk_emit+0x3da/0x3e4
 [<81425f76>] printk+0x17/0x19
 [<8105bfa0>] clockevents_program_min_delta+0x104/0x116
 [<8105cc1c>] tick_program_event+0x1e/0x23
 [<8103c43c>] hrtimer_force_reprogram+0x88/0x8f
 [<8103c49e>] __remove_hrtimer+0x5b/0x79
 [<8103cb21>] hrtimer_try_to_cancel+0x49/0x66
 [<8103cb4b>] hrtimer_cancel+0xd/0x18
 [<8107f102>] perf_swevent_cancel_hrtimer.part.60+0x2b/0x30
 [<81080705>] task_clock_event_stop+0x20/0x64
 [<81080756>] task_clock_event_del+0xd/0xf
 [<81081350>] event_sched_out+0xab/0x11e
 [<810813e0>] group_sched_out+0x1d/0x66
 [<81081682>] ctx_sched_out+0xaf/0xbf
 [<81081e04>] __perf_event_task_sched_out+0x1ed/0x34f
 [<8104416d>] ? __dequeue_entity+0x23/0x27
 [<81044505>] ? pick_next_task_fair+0xb1/0x120
 [<8142cacc>] __schedule+0x4c6/0x4cb
 [<81047574>] ? trace_hardirqs_off_caller+0xd7/0x108
 [<810475b0>] ? trace_hardirqs_off+0xb/0xd
 [<81056346>] ? rcu_irq_exit+0x64/0x77

Fix the problem by using printk_deferred() which does not call into the
scheduler.

Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>