commits

Not all I/O ASIC versions have the free-running counter implemented, an
early revision used in the 5000/1xx models aka 3MIN and 4MIN did not have
it. Therefore we cannot unconditionally use it as a clock source.
Fortunately if not implemented its register slot has a fixed value so it
is enough if we check for the value at the end of the calibration period
being the same as at the beginning.

This also means we need to look for another high-precision clock source on
the systems affected. The 5000/1xx can have an R4000SC processor
installed where the CP0 Count register can be used as a clock source.
Unfortunately all the R4k DECstations suffer from the missed timer
interrupt on CP0 Count reads erratum, so we cannot use the CP0 timer as a
clock source and a clock event both at a time. However we never need an
R4k clock event device because all DECstations have a DS1287A RTC chip
whose periodic interrupt can be used as a clock source.

This gives us the following four configuration possibilities for I/O ASIC
DECstations:

1. No I/O ASIC counter and no CP0 timer, e.g. R3k 5000/1xx (3MIN).

2. No I/O ASIC counter but the CP0 timer, i.e. R4k 5000/150 (4MIN).

3. The I/O ASIC counter but no CP0 timer, e.g. R3k 5000/240 (3MAX+).

4. The I/O ASIC counter and the CP0 timer, e.g. R4k 5000/260 (4MAX+).

For #1 and #2 this change stops the I/O ASIC free-running counter from
being installed as a clock source of a 0Hz frequency. For #2 it also
arranges for the CP0 timer to be used as a clock source rather than a
clock event device, because having an accurate wall clock is more
important than a high-precision interval timer. For #3 there is no
change. For #4 the change makes the I/O ASIC free-running counter
installed as a clock source so that the CP0 timer can be used as a clock
event device.

Unfortunately the use of the CP0 timer as a clock event device relies on a
succesful completion of c0_compare_interrupt. That never happens, because
while waiting for a CP0 Compare interrupt to happen the function spins in
a loop reading the CP0 Count register. This makes the CP0 Count erratum
trigger reliably causing the interrupt waited for to be lost in all cases.
As a result #4 resorts to using the CP0 timer as a clock source as well,
just as #2. However we want to keep this separate arrangement in case
(hope) c0_compare_interrupt is eventually rewritten such that it avoids
the erratum.

Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/5825/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

12y ago

Linus Torvalds

30b229bd

Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

12y ago

Michael Neuling

28e61cc4

powerpc/tm: Fix context switching TAR, PPR and DSCR SPRs

12y ago

Chris Leech

e09056b2

[SCSI] fnic: BUG: sleeping function called from invalid context during probe

I hit this during driver probe with the latest fnic updates (this trace
is from a backport into a distro kernel, but the issue is the same).

> BUG: sleeping function called from invalid context at mm/slab.c:3113
> in_atomic(): 0, irqs_disabled(): 1, pid: 610, name: work_for_cpu
> INFO: lockdep is turned off.
> irq event stamp: 0
> hardirqs last enabled at (0): [<(null)>] (null)
> hardirqs last disabled at (0): [<ffffffff81070aa5>]
> copy_process+0x5e5/0x1670
> softirqs last enabled at (0): [<ffffffff81070aa5>]
> copy_process+0x5e5/0x1670
> softirqs last disabled at (0): [<(null)>] (null)
> Pid: 610, comm: work_for_cpu Not tainted
> Call Trace:
> [<ffffffff810b2d10>] ? print_irqtrace_events+0xd0/0xe0
> [<ffffffff8105c1a7>] ? __might_sleep+0xf7/0x130
> [<ffffffff81184efb>] ? kmem_cache_alloc_trace+0x20b/0x2d0
> [<ffffffff8109709e>] ? __create_workqueue_key+0x3e/0x1d0
> [<ffffffff8109709e>] ? __create_workqueue_key+0x3e/0x1d0
> [<ffffffffa00c101c>] ? fnic_probe+0x977/0x11aa [fnic]
> [<ffffffffa00c1048>] ? fnic_probe+0x9a3/0x11aa [fnic]
> [<ffffffff81096f00>] ? do_work_for_cpu+0x0/0x30
> [<ffffffff812c6da7>] ? local_pci_probe+0x17/0x20
> [<ffffffff81096f18>] ? do_work_for_cpu+0x18/0x30
> [<ffffffff8109cdc6>] ? kthread+0x96/0xa0
> [<ffffffff8100c1ca>] ? child_rip+0xa/0x20
> [<ffffffff81550f80>] ? _spin_unlock_irq+0x30/0x40
> [<ffffffff8100bb10>] ? restore_args+0x0/0x30
> [<ffffffff8109cd30>] ? kthread+0x0/0xa0
> [<ffffffff8100c1c0>] ? child_rip+0x0/0x20

The problem is in this hunk of "FIP VLAN Discovery Feature Support"
(d3c995f1dcf938f1084388d92b8fb97bec366566)

create_singlethreaded_workqueue cannot be called with irqs disabled

@@ -620,7 +634,29 @@ static int __devinit fnic_probe(struct pci_dev
*pdev,
vnic_dev_packet_filter(fnic->vdev, 1, 1, 0, 0, 0);
vnic_dev_add_addr(fnic->vdev, FIP_ALL_ENODE_MACS);
vnic_dev_add_addr(fnic->vdev, fnic->ctlr.ctl_src_addr);
+ fnic->set_vlan = fnic_set_vlan;
fcoe_ctlr_init(&fnic->ctlr, FIP_MODE_AUTO);
+ setup_timer(&fnic->fip_timer, fnic_fip_notify_timer,
+ (unsigned long)fnic);
+ spin_lock_init(&fnic->vlans_lock);
+ INIT_WORK(&fnic->fip_frame_work, fnic_handle_fip_frame);
+ INIT_WORK(&fnic->event_work, fnic_handle_event);
+ skb_queue_head_init(&fnic->fip_frame_queue);
+ spin_lock_irqsave(&fnic_list_lock, flags);
+ if (!fnic_fip_queue) {
+ fnic_fip_queue =
+ create_singlethread_workqueue("fnic_fip_q");
+ if (!fnic_fip_queue) {
+ spin_unlock_irqrestore(&fnic_list_lock, flags);
+ printk(KERN_ERR PFX "fnic FIP work queue "
+ "create failed\n");
+ err = -ENOMEM;
+ goto err_out_free_max_pool;
+ }
+ }
+ spin_unlock_irqrestore(&fnic_list_lock, flags);
+ INIT_LIST_HEAD(&fnic->evlist);
+ INIT_LIST_HEAD(&fnic->vlans);
} else {
shost_printk(KERN_INFO, fnic->lport->host,
"firmware uses non-FIP mode\n");

The attempts to make fnic_fip_queue a single instance for the driver
while it's being created in probe look awkward anyway, why is this not
created in fnic_init_module like the event workqueue?

Signed-off-by: Chris Leech <cleech@redhat.com>
Tested-by: Anantha Tungarakodi <atungara@cisco.com>
Acked-by: Hiral Patel <hiralpat@cisco.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

12y ago

Guenter Roeck

215b28a5

s390: Fix broken build

12y ago

Jan Kara

a361293f

jbd2: Fix oops in jbd2_journal_file_inode()

12y ago

Li Zefan

da0a12ca

cgroup: fix a leak when percpu_ref_init() fails

12y ago

Linus Torvalds

399a946e

Merge branch 'genirq' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux

12y ago

Artem Savkov

d9b2c871

aio: rcu_read_lock protection for new rcu_dereference calls

12y ago

Baruch Siach

8d5e1d8e

xtensa: remove CCOUNT_PER_JIFFY

12y ago

Sachin Kamat

17a52100

hwmon: (amc6821) Remove redundant break

12y ago

Ezequiel Garcia

ad48bd61

clocksource: armada-370-xp: Use BIT()

12y ago

Linus Torvalds

05a8252b

vfs: fix typo in comment in recent dentry work

12y ago

David Herrmann

c7dc6573

Input: evdev - add EVIOCREVOKE ioctl

If we have multiple sessions on a system, we normally don't want
background sessions to read input events. Otherwise, it could capture
passwords and more entered by the user on the foreground session. This is
a real world problem as the recent XMir development showed:
http://mjg59.dreamwidth.org/27327.html

We currently rely on sessions to release input devices when being
deactivated. This relies on trust across sessions. But that's not given on
usual systems. We therefore need a way to control which processes have
access to input devices.

With VTs the kernel simply routed them through the active /dev/ttyX. This
is not possible with evdev devices, though. Moreover, we want to avoid
routing input-devices through some dispatcher-daemon in userspace (which
would add some latency).

This patch introduces EVIOCREVOKE. If called on an evdev fd, this revokes
device-access irrecoverably for that *single* open-file. Hence, once you
call EVIOCREVOKE on any dup()ed fd, all fds for that open-file will be
rather useless now (but still valid compared to close()!). This allows us
to pass fds directly to session-processes from a trusted source. The
source keeps a dup()ed fd and revokes access once the session-process is
no longer active.
Compared to the EVIOCMUTE proposal, we can avoid the CAP_SYS_ADMIN
restriction now as there is no way to revive the fd again. Hence, a user
is free to call EVIOCREVOKE themself to kill the fd.

Additionally, this ioctl allows multi-layer access-control (again compared
to EVIOCMUTE which was limited to one layer via CAP_SYS_ADMIN). A middle
layer can simply request a new open-file from the layer above and pass it
to the layer below. Now each layer can call EVIOCREVOKE on the fds to
revoke access for all layers below, at the expense of one fd per layer.

There's already ongoing experimental user-space work which demonstrates
how it can be used:
http://lists.freedesktop.org/archives/systemd-devel/2013-August/012897.html

Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>