There was a very small race window where resume to kernel mode from a
Exception Path (or pure kernel mode which is true for most of ARC
exceptions anyways), was not disabling interrupts in restore_regs,
clobbering the exception regs
Anton found the culprit call flow (after many sleepless nights)
| 1. we got a Trap from user land
| 2. started to service it.
| 3. While doing some stuff on user-land memory (I think it is padzero()),
| we got a DataTlbMiss
| 4. On return from it we are taking "resume_kernel_mode" path
| 5. NEED_RESHED is not set, so we go to "return from exception" path in
| restore regs.
| 6. there seems to be IRQ happening
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Cc: <stable@vger.kernel.org> #3.10, 3.12, 3.13, 3.14
Cc: Anton Kolesov <Anton.Kolesov@synopsys.com>
Cc: Francois Bedard <Francois.Bedard@synopsys.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull devicetree bug fixes from Grant Likely:
"These are some important bug fixes that need to get into v3.15.
This branch contains a pair of important bug fixes for the DT code:
- Fix some incorrect binding property names before they enter common
usage
- Fix bug where some platform devices will be unable to get their
interrupt number when they depend on an interrupt controller that
is not available at device creation time. This is a problem
causing mainline to fail on a number of ARM platforms"
* tag 'dt-for-linus' of git://git.secretlab.ca/git/linux:
of/irq: do irq resolution in platform_get_irq
of: selftest: add deferred probe interrupt test
dt: Fix binding typos in clock-names and interrupt-names
Pull powerpc fixes from Ben Herrenschmidt:
"Here is a bunch of post-merge window fixes that have been accumulating
in patchwork while I was on vacation or buried under other stuff last
week.
We have the now usual batch of LE fixes from Anton (sadly some new
stuff that went into this merge window had endian issues, we'll try to
make sure we do better next time)
Some fixes and cleanups to the new 24x7 performance monitoring stuff
(mostly typos and cleaning up printk's)
A series of fixes for an issue with our runlatch bit, which wasn't set
properly for offlined threads/cores and under KVM, causing potentially
some counters to misbehave along with possible power management
issues.
A fix for kexec nasty race where the new kernel wouldn't "see" the
secondary processors having reached back into firmware in time.
And finally a few other misc (and pretty simple) bug fixes"
* 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc: (33 commits)
powerpc/4xx: Fix section mismatch in ppc4xx_pci.c
ppc/kvm: Clear the runlatch bit of a vcpu before napping
ppc/kvm: Set the runlatch bit of a CPU just before starting guest
ppc/powernv: Set the runlatch bits correctly for offline cpus
powerpc/pseries: Protect remove_memory() with device hotplug lock
powerpc: Fix error return in rtas_flash module init
powerpc: Bump BOOT_COMMAND_LINE_SIZE to 2048
powerpc: Bump COMMAND_LINE_SIZE to 2048
powerpc: Rename duplicate COMMAND_LINE_SIZE define
powerpc/perf/hv-24x7: Catalog version number is be64, not be32
powerpc/perf/hv-24x7: Remove [static 4096], sparse chokes on it
powerpc/perf/hv-24x7: Use (unsigned long) not (u32) values when calling plpar_hcall_norets()
powerpc/perf/hv-gpci: Make device attr static
powerpc/perf/hv_gpci: Probe failures use pr_debug(), and padding reduced
powerpc/perf/hv_24x7: Probe errors changed to pr_debug(), padding fixed
powerpc/mm: Fix tlbie to add AVAL fields for 64K pages
powerpc/powernv: Fix little endian issues in OPAL dump code
powerpc/powernv: Create OPAL sglist helper functions and fix endian issues
powerpc/powernv: Fix little endian issues in OPAL error log code
powerpc/powernv: Fix little endian issues with opal_do_notifier calls
...
This patch fixes this section mismatch:
WARNING: vmlinux.o(.text+0x1efc4): Section mismatch in reference from
the function apm821xx_pciex_init_port_hw() to the function
.init.text:ppc4xx_pciex_wait_on_sdr.isra.9()
The function apm821xx_pciex_init_port_hw() references the function
__init ppc4xx_pciex_wait_on_sdr.isra.9(). This is often because
apm821xx_pciex_init_port_hw lacks a __init annotation or the
annotation of ppc4xx_pciex_wait_on_sdr.isra.9 is wrong.
apm821xx_pciex_init_port_hw is only referenced by a struct in
__initdata, so it should be safe to add __init to
apm821xx_pciex_init_port_hw.
Signed-off-by: Alistair Popple <alistair@popple.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
The secondary threads in the core are kept offline before launching guests
in kvm on powerpc: "371fefd6f2dc4666:KVM: PPC: Allow book3s_hv guests to use
SMT processor modes."
Hence their runlatch bits are cleared. When the secondary threads are called
in to start a guest, their runlatch bits need to be set to indicate that they
are busy. The primary thread has its runlatch bit set though, but there is no
harm in setting this bit once again. Hence set the runlatch bit for all
threads before they start guest.
Signed-off-by: Preeti U Murthy <preeti@linux.vnet.ibm.com>
Acked-by: Paul Mackerras <paulus@samba.org>
Reviewed-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Up until now we have been setting the runlatch bits for a busy CPU and
clearing it when a CPU enters idle state. The runlatch bit has thus
been consistent with the utilization of a CPU as long as the CPU is online.
However when a CPU is hotplugged out the runlatch bit is not cleared. It
needs to be cleared to indicate an unused CPU. Hence this patch has the
runlatch bit cleared for an offline CPU just before entering an idle state
and sets it immediately after it exits the idle state.
Signed-off-by: Preeti U Murthy <preeti@linux.vnet.ibm.com>
Acked-by: Paul Mackerras <paulus@samba.org>
Reviewed-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
While testing memory hot-remove, I found following dead lock:
Process #1141 is drmgr, trying to remove some memory, i.e. memory499.
It holds the memory_hotplug_mutex, and blocks when trying to remove file
"online" under dir memory499, in kernfs_drain(), at
wait_event(root->deactivate_waitq,
atomic_read(&kn->active) == KN_DEACTIVATED_BIAS);
Process #1120 is trying to online memory499 by
echo 1 > memory499/online
In .kernfs_fop_write, it uses kernfs_get_active() to increase
&kn->active, thus blocking process #1141. While itself is blocked later
when trying to acquire memory_hotplug_mutex, which is held by process
The backtrace of both processes are shown below:
[<c000000001b18600>] 0xc000000001b18600
[<c000000000015044>] .__switch_to+0x144/0x200
[<c000000000263ca4>] .online_pages+0x74/0x7b0
[<c00000000055b40c>] .memory_subsys_online+0x9c/0x150
[<c00000000053cbe8>] .device_online+0xb8/0x120
[<c00000000053cd04>] .online_store+0xb4/0xc0
[<c000000000538ce4>] .dev_attr_store+0x64/0xa0
[<c00000000030f4ec>] .sysfs_kf_write+0x7c/0xb0
[<c00000000030e574>] .kernfs_fop_write+0x154/0x1e0
[<c000000000268450>] .vfs_write+0xe0/0x260
[<c000000000269144>] .SyS_write+0x64/0x110
[<c000000000009ffc>] syscall_exit+0x0/0x7c
[<c000000001b18600>] 0xc000000001b18600
[<c000000000015044>] .__switch_to+0x144/0x200
[<c00000000030be14>] .__kernfs_remove+0x204/0x300
[<c00000000030d428>] .kernfs_remove_by_name_ns+0x68/0xf0
[<c00000000030fb38>] .sysfs_remove_file_ns+0x38/0x60
[<c000000000539354>] .device_remove_attrs+0x54/0xc0
[<c000000000539fd8>] .device_del+0x158/0x250
[<c00000000053a104>] .device_unregister+0x34/0xa0
[<c00000000055bc14>] .unregister_memory_section+0x164/0x170
[<c00000000024ee18>] .__remove_pages+0x108/0x4c0
[<c00000000004b590>] .arch_remove_memory+0x60/0xc0
[<c00000000026446c>] .remove_memory+0x8c/0xe0
[<c00000000007f9f4>] .pseries_remove_memblock+0xd4/0x160
[<c00000000007fcfc>] .pseries_memory_notifier+0x27c/0x290
[<c0000000008ae6cc>] .notifier_call_chain+0x8c/0x100
[<c0000000000d858c>] .__blocking_notifier_call_chain+0x6c/0xe0
[<c00000000071ddec>] .of_property_notify+0x7c/0xc0
[<c00000000071ed3c>] .of_update_property+0x3c/0x1b0
[<c0000000000756cc>] .ofdt_write+0x3dc/0x740
[<c0000000002f60fc>] .proc_reg_write+0xac/0x110
[<c000000000268450>] .vfs_write+0xe0/0x260
[<c000000000269144>] .SyS_write+0x64/0x110
[<c000000000009ffc>] syscall_exit+0x0/0x7c
This patch uses lock_device_hotplug() to protect remove_memory() called
in pseries_remove_memblock(), which is also stated before function
remove_memory():
* NOTE: The caller must call lock_device_hotplug() to serialize hotplug
* and online/offline operations before this call, as required by
* try_offline_node().
*/
void __ref remove_memory(int nid, u64 start, u64 size)
With this lock held, the other process(#1120 above) trying to online the
memory block will retry the system call when calling
lock_device_hotplug_sysfs(), and finally find No such device error.
Signed-off-by: Li Zhong <zhong@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
module_init should return 0 or a negative errno.
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Bump the boot wrapper BOOT_COMMAND_LINE_SIZE to match the
kernel.
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
I've had a report that the current limit is too small for
an automated network based installer. Bump it.
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
We have two definitions of COMMAND_LINE_SIZE, one for the kernel
and one for the boot wrapper. I assume this is so the boot
wrapper can be self sufficient and not rely on kernel headers.
Having two defines with the same name is confusing, I just
updated the wrong one when trying to bump it.
Make the boot wrapper define unique by calling it
BOOT_COMMAND_LINE_SIZE.
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
The catalog version number was changed from a be32 (with proceeding
32bits of padding) to a be64, update the code to treat it as a be64
Signed-off-by: Cody P Schafer <cody@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
fixup for "powerpc/perf: Add support for the hv gpci (get performance
counter info) interface".
Makes the "not enabled" message less awful (and hidden unless
debugging).
Signed-off-by: Cody P Schafer <cody@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
fixup for "powerpc/perf: Add support for the hv 24x7 interface"
Makes the "not enabled" message less awful (and hides it in most cases).
Signed-off-by: Cody P Schafer <cody@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
We have two copies of code that creates an OPAL sg list. Consolidate
these into a common set of helpers and fix the endian issues.
The flash interface embedded a version number in the num_entries
field, whereas the dump interface did did not. Since versioning
wasn't added to the flash interface and it is impossible to add
this in a backwards compatible way, just remove it.
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
The bitmap in opal_poll_events and opal_handle_interrupt is
big endian, so we need to byteswap it on little endian builds.
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
We had some duplication of the internal OPAL functions.
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Using size_t in our APIs is asking for trouble, especially
when some OPAL calls use size_t pointers.
Signed-off-by: Anton Blanchard <anton@samba.org>
Reviewed-by: Stewart Smith <stewart@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
