linux-toradex.git/arch/x86, branch v3.11

Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2013-09-02T16:55:14+00:00

Pull x86 boot fix from Peter Anvin:
 "A single very small boot fix for very large memory systems (> 0.5T)"

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/mm: Fix boot crash with DEBUG_PAGE_ALLOC=y and more than 512G RAM

x86 get_unmapped_area: Access mmap_legacy_base through mm_struct member

2013-08-22T17:19:35+00:00

This is the updated version of df54d6fa5427 ("x86 get_unmapped_area():
use proper mmap base for bottom-up direction") that only randomizes the
mmap base address once.

Signed-off-by: Radu Caragea 
Reported-and-tested-by: Jeff Shorey 
Cc: Andrew Morton 
Cc: Michel Lespinasse 
Cc: Oleg Nesterov 
Cc: Rik van Riel 
Cc: Ingo Molnar 
Cc: Adrian Sendroiu 
Cc: Greg KH 
Cc: Kamal Mostafa 
Signed-off-by: Linus Torvalds

Revert "x86 get_unmapped_area(): use proper mmap base for bottom-up direction"

2013-08-22T17:18:44+00:00

This reverts commit df54d6fa54275ce59660453e29d1228c2b45a826.

The commit isn't necessarily wrong, but because it recalculates the
random mmap_base every time, it seems to confuse user memory allocators
that expect contiguous mmap allocations even when the mmap address isn't
specified.

In particular, the MATLAB Java runtime seems to be unhappy. See

  https://bugzilla.kernel.org/show_bug.cgi?id=60774

So we'll want to apply the random offset only once, and Radu has a patch
for that.  Revert this older commit in order to apply the other one.

Reported-by: Jeff Shorey 
Cc: Radu Caragea 
Cc: Andrew Morton 
Signed-off-by: Linus Torvalds

Merge tag 'stable/for-linus-3.11-rc6-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip

2013-08-21T23:38:33+00:00

Pull Xen bug-fixes from Konrad Rzeszutek Wilk:
 - On ARM did not have balanced calls to get/put_cpu.
 - Fix to make tboot + Xen + Linux correctly.
 - Fix events VCPU binding issues.
 - Fix a vCPU online race where IPIs are sent to not-yet-online vCPU.

* tag 'stable/for-linus-3.11-rc6-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  xen/smp: initialize IPI vectors before marking CPU online
  xen/events: mask events when changing their VCPU binding
  xen/events: initialize local per-cpu mask for all possible events
  x86/xen: do not identity map UNUSABLE regions in the machine E820
  xen/arm: missing put_cpu in xen_percpu_init

xen/smp: initialize IPI vectors before marking CPU online

2013-08-20T14:13:05+00:00

An older PVHVM guest (v3.0 based) crashed during vCPU hot-plug with:

	kernel BUG at drivers/xen/events.c:1328!

RCU has detected that a CPU has not entered a quiescent state within the
grace period.  It needs to send the CPU a reschedule IPI if it is not
offline.  rcu_implicit_offline_qs() does this check:

	/*
	 * If the CPU is offline, it is in a quiescent state.  We can
	 * trust its state not to change because interrupts are disabled.
	 */
	if (cpu_is_offline(rdp->cpu)) {
		rdp->offline_fqs++;
		return 1;
	}

	Else the CPU is online.  Send it a reschedule IPI.

The CPU is in the middle of being hot-plugged and has been marked online
(!cpu_is_offline()).  See start_secondary():

	set_cpu_online(smp_processor_id(), true);
	...
	per_cpu(cpu_state, smp_processor_id()) = CPU_ONLINE;

start_secondary() then waits for the CPU bringing up the hot-plugged CPU to
mark it as active:

	/*
	 * Wait until the cpu which brought this one up marked it
	 * online before enabling interrupts. If we don't do that then
	 * we can end up waking up the softirq thread before this cpu
	 * reached the active state, which makes the scheduler unhappy
	 * and schedule the softirq thread on the wrong cpu. This is
	 * only observable with forced threaded interrupts, but in
	 * theory it could also happen w/o them. It's just way harder
	 * to achieve.
	 */
	while (!cpumask_test_cpu(smp_processor_id(), cpu_active_mask))
		cpu_relax();

	/* enable local interrupts */
	local_irq_enable();

The CPU being hot-plugged will be marked active after it has been fully
initialized by the CPU managing the hot-plug.  In the Xen PVHVM case
xen_smp_intr_init() is called to set up the hot-plugged vCPU's
XEN_RESCHEDULE_VECTOR.

The hot-plugging CPU is marked online, not marked active and does not have
its IPI vectors set up.  rcu_implicit_offline_qs() sees the hot-plugging
cpu is !cpu_is_offline() and tries to send it a reschedule IPI:
This will lead to:

	kernel BUG at drivers/xen/events.c:1328!

	xen_send_IPI_one()
	xen_smp_send_reschedule()
	rcu_implicit_offline_qs()
	rcu_implicit_dynticks_qs()
	force_qs_rnp()
	force_quiescent_state()
	__rcu_process_callbacks()
	rcu_process_callbacks()
	__do_softirq()
	call_softirq()
	do_softirq()
	irq_exit()
	xen_evtchn_do_upcall()

because xen_send_IPI_one() will attempt to use an uninitialized IRQ for
the XEN_RESCHEDULE_VECTOR.

There is at least one other place that has caused the same crash:

	xen_smp_send_reschedule()
	wake_up_idle_cpu()
	add_timer_on()
	clocksource_watchdog()
	call_timer_fn()
	run_timer_softirq()
	__do_softirq()
	call_softirq()
	do_softirq()
	irq_exit()
	xen_evtchn_do_upcall()
	xen_hvm_callback_vector()

clocksource_watchdog() uses cpu_online_mask to pick the next CPU to handle
a watchdog timer:

	/*
	 * Cycle through CPUs to check if the CPUs stay synchronized
	 * to each other.
	 */
	next_cpu = cpumask_next(raw_smp_processor_id(), cpu_online_mask);
	if (next_cpu >= nr_cpu_ids)
		next_cpu = cpumask_first(cpu_online_mask);
	watchdog_timer.expires += WATCHDOG_INTERVAL;
	add_timer_on(&watchdog_timer, next_cpu);

This resulted in an attempt to send an IPI to a hot-plugging CPU that
had not initialized its reschedule vector. One option would be to make
the RCU code check to not check for CPU offline but for CPU active.
As becoming active is done after a CPU is online (in older kernels).

But Srivatsa pointed out that "the cpu_active vs cpu_online ordering has been
completely reworked - in the online path, cpu_active is set *before* cpu_online,
and also, in the cpu offline path, the cpu_active bit is reset in the CPU_DYING
notification instead of CPU_DOWN_PREPARE." Drilling in this the bring-up
path: "[brought up CPU].. send out a CPU_STARTING notification, and in response
to that, the scheduler sets the CPU in the cpu_active_mask. Again, this mask
is better left to the scheduler alone, since it has the intelligence to use it
judiciously."

The conclusion was that:
"
1. At the IPI sender side:

   It is incorrect to send an IPI to an offline CPU (cpu not present in
   the cpu_online_mask). There are numerous places where we check this
   and warn/complain.

2. At the IPI receiver side:

   It is incorrect to let the world know of our presence (by setting
   ourselves in global bitmasks) until our initialization steps are complete
   to such an extent that we can handle the consequences (such as
   receiving interrupts without crashing the sender etc.)
" (from Srivatsa)

As the native code enables the interrupts at some point we need to be
able to service them. In other words a CPU must have valid IPI vectors
if it has been marked online.

It doesn't need to handle the IPI (interrupts may be disabled) but needs
to have valid IPI vectors because another CPU may find it in cpu_online_mask
and attempt to send it an IPI.

This patch will change the order of the Xen vCPU bring-up functions so that
Xen vectors have been set up before start_secondary() is called.
It also will not continue to bring up a Xen vCPU if xen_smp_intr_init() fails
to initialize it.

Orabug 13823853
Signed-off-by Chuck Anderson 
Acked-by: Srivatsa S. Bhat 
Signed-off-by: Konrad Rzeszutek Wilk

x86/xen: do not identity map UNUSABLE regions in the machine E820

2013-08-20T13:46:06+00:00

If there are UNUSABLE regions in the machine memory map, dom0 will
attempt to map them 1:1 which is not permitted by Xen and the kernel
will crash.

There isn't anything interesting in the UNUSABLE region that the dom0
kernel needs access to so we can avoid making the 1:1 mapping and
treat it as RAM.

We only do this for dom0, as that is where tboot case shows up.
A PV domU could have an UNUSABLE region in its pseudo-physical map
and would need to be handled in another patch.

This fixes a boot failure on hosts with tboot.

tboot marks a region in the e820 map as unusable and the dom0 kernel
would attempt to map this region and Xen does not permit unusable
regions to be mapped by guests.

  (XEN)  0000000000000000 - 0000000000060000 (usable)
  (XEN)  0000000000060000 - 0000000000068000 (reserved)
  (XEN)  0000000000068000 - 000000000009e000 (usable)
  (XEN)  0000000000100000 - 0000000000800000 (usable)
  (XEN)  0000000000800000 - 0000000000972000 (unusable)

tboot marked this region as unusable.

  (XEN)  0000000000972000 - 00000000cf200000 (usable)
  (XEN)  00000000cf200000 - 00000000cf38f000 (reserved)
  (XEN)  00000000cf38f000 - 00000000cf3ce000 (ACPI data)
  (XEN)  00000000cf3ce000 - 00000000d0000000 (reserved)
  (XEN)  00000000e0000000 - 00000000f0000000 (reserved)
  (XEN)  00000000fe000000 - 0000000100000000 (reserved)
  (XEN)  0000000100000000 - 0000000630000000 (usable)

Signed-off-by: David Vrabel 
[v1: Altered the patch and description with domU's with UNUSABLE regions]
Signed-off-by: Konrad Rzeszutek Wilk

x86/mm: Fix boot crash with DEBUG_PAGE_ALLOC=y and more than 512G RAM

2013-08-20T08:06:50+00:00

Dave Hansen reported that systems between 500G and 600G RAM
crash early if DEBUG_PAGEALLOC is selected.

 > [    0.000000] init_memory_mapping: [mem 0x00000000-0x000fffff]
 > [    0.000000]  [mem 0x00000000-0x000fffff] page 4k
 > [    0.000000] BRK [0x02086000, 0x02086fff] PGTABLE
 > [    0.000000] BRK [0x02087000, 0x02087fff] PGTABLE
 > [    0.000000] BRK [0x02088000, 0x02088fff] PGTABLE
 > [    0.000000] init_memory_mapping: [mem 0xe80ee00000-0xe80effffff]
 > [    0.000000]  [mem 0xe80ee00000-0xe80effffff] page 4k
 > [    0.000000] BRK [0x02089000, 0x02089fff] PGTABLE
 > [    0.000000] BRK [0x0208a000, 0x0208afff] PGTABLE
 > [    0.000000] Kernel panic - not syncing: alloc_low_page: ran out of memory

It turns out that we missed increasing needed pages in BRK to
mapping initial 2M and [0,1M) when we switched to use the #PF
handler to set memory mappings:

 > commit 8170e6bed465b4b0c7687f93e9948aca4358a33b
 > Author: H. Peter Anvin 
 > Date:   Thu Jan 24 12:19:52 2013 -0800
 >
 >     x86, 64bit: Use a #PF handler to materialize early mappings on demand

Before that, we had the maping from [0,512M) in head_64.S, and we
can spare two pages [0-1M).  After that change, we can not reuse
pages anymore.

When we have more than 512M ram, we need an extra page for pgd page
with [512G, 1024g).

Increase pages in BRK for page table to solve the boot crash.

Reported-by: Dave Hansen 
Bisected-by: Dave Hansen 
Tested-by: Dave Hansen 
Signed-off-by: Yinghai Lu 
Cc:  # v3.9 and later
Link: http://lkml.kernel.org/r/1376351004-4015-1-git-send-email-yinghai@kernel.org
Signed-off-by: Ingo Molnar

Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2013-08-19T16:18:29+00:00

Pull x86 fixes from Ingo Molnar:
 "Two AMD microcode loader fixes and an OLPC firmware support fix"

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86, microcode, AMD: Fix early microcode loading
  x86, microcode, AMD: Make cpu_has_amd_erratum() use the correct struct cpuinfo_x86
  x86: Don't clear olpc_ofw_header when sentinel is detected

Merge branch 'akpm' (patches from Andrew Morton)

2013-08-14T17:04:43+00:00

Merge a bunch of fixes from Andrew Morton.

* emailed patches from Andrew Morton :
  fs/proc/task_mmu.c: fix buffer overflow in add_page_map()
  arch: *: Kconfig: add "kernel/Kconfig.freezer" to "arch/*/Kconfig"
  ocfs2: fix null pointer dereference in ocfs2_dir_foreach_blk_id()
  x86 get_unmapped_area(): use proper mmap base for bottom-up direction
  ocfs2: fix NULL pointer dereference in ocfs2_duplicate_clusters_by_page
  ocfs2: Revert 40bd62e to avoid regression in extended allocation
  drivers/rtc/rtc-stmp3xxx.c: provide timeout for potentially endless loop polling a HW bit
  hugetlb: fix lockdep splat caused by pmd sharing
  aoe: adjust ref of head for compound page tails
  microblaze: fix clone syscall
  mm: save soft-dirty bits on file pages
  mm: save soft-dirty bits on swapped pages
  memcg: don't initialize kmem-cache destroying work for root caches

Merge tag 'amd_ucode_fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/bp/bp into x86/urgent

2013-08-14T10:16:28+00:00

Pull AMD microcode fixes from Borislav Petkov:

 " Those are basically two fixes which correct the AMD early ucode loader
   from accessing cpu_data too early, i.e. before smp_store_cpu_info()
   has copied the boot_cpu_data ontop and overwritten an already empty
   structure (which we shouldn't access that early in the first place
   anyway).

   The second patch is kinda largish for that late in the game but it
   shouldn't be problematic because we're simply switching from using
   cpu_data to use the CPU family number directly and thus again, not use
   uninitialized cpu_data structure. "

Signed-off-by: Ingo Molnar