Commit Graph

440881 Commits

Author SHA1 Message Date
David Hildenbrand
af1827e773 KVM: s390: kernel header addition for guest debugging
This patch adds the structs to the kernel headers needed to pass information
from/to userspace in order to debug a guest on s390 with hardware support.

Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
2014-04-22 13:24:50 +02:00
David Hildenbrand
aba0750889 KVM: s390: emulate stctl and stctg
Introduce the methods to emulate the stctl and stctg instruction. Added tracing
code.

Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
2014-04-22 13:24:50 +02:00
David Hildenbrand
8712836b30 KVM: s390: deliver program irq parameters and use correct ilc
When a program interrupt was to be delivered until now, no program interrupt
parameters were stored in the low-core of the target vcpu.

This patch enables the delivery of those program interrupt parameters, takes
care of concurrent PER events which can be injected in addition to any program
interrupt and uses the correct instruction length code (depending on the
interception code) for the injection of program interrupts.

Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
2014-04-22 13:24:49 +02:00
David Hildenbrand
439716a5ca KVM: s390: extract irq parameters of intercepted program irqs
Whenever a program interrupt is intercepted, some parameters are stored in the
sie control block. These parameters have to be extracted in order to be
reinjected correctly. This patch also takes care of intercepted PER events which
can occurr in addition to any program interrupt.

Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
2014-04-22 13:24:49 +02:00
Jens Freimann
da7cf2570c s390: add fields to lowcore definition
This patch adds fields which are currently missing but needed for the correct
injection of interrupts.

This is based on a patch by David Hildenbrand

Signed-off-by: Jens Freimann <jfrei@linux.vnet.ibm.com>
Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
2014-04-22 13:24:49 +02:00
Jens Freimann
21ee7ffd17 s390: rename and split lowcore field per_perc_atmid
per_perc_atmid is currently a two-byte field that combines two
fields, the PER code and the PER Addressing-and-Translation-Mode
Identification (ATMID)

Let's make them accessible indepently and also rename per_cause to
per_code.

Signed-off-by: Jens Freimann <jfrei@linux.vnet.ibm.com>
Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
2014-04-22 13:24:48 +02:00
Jens Freimann
3d53b46ce8 s390: fix name of lowcore field at offset 0xa3
According to the Principles of Operation, at offset 0xA3
in the lowcore we have the "Architectural-Mode identification",
not an "access identification".

Signed-off-by: Jens Freimann <jfrei@linux.vnet.ibm.com>
Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
2014-04-22 13:24:48 +02:00
Heiko Carstens
e497a96ae8 KVM: s390: cleanup kvm_s390_real_to_abs()
Add kerneldoc comment to kvm_s390_real_to_abs() and change the code
so it matches the coding style of the rest of gaccess.h.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Reviewed-by: Thomas Huth <thuth@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
2014-04-22 13:24:47 +02:00
Heiko Carstens
3263bd1637 KVM: s390: remove old guest access functions
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Reviewed-by: Thomas Huth <thuth@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
2014-04-22 13:24:47 +02:00
Heiko Carstens
645c5bc1d5 KVM: s390: convert handle_stsi()
Convert handle_stsi() to new guest access functions.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Reviewed-by: Thomas Huth <thuth@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
2014-04-22 13:24:46 +02:00
Heiko Carstens
f987a3eef0 KVM: s390: convert handle lctl[g]()
Convert handle lctl[g]() to new guest access functions.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Reviewed-by: Thomas Huth <thuth@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
2014-04-22 13:24:46 +02:00
Heiko Carstens
7d777d7824 KVM: s390: convert handle_stidp()
Convert handle_stidp() to new guest access functions.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Reviewed-by: Thomas Huth <thuth@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
2014-04-22 13:24:45 +02:00
Heiko Carstens
2d8bcaeda1 KVM: s390: convert handle_lpsw[e]()
Convert handle_lpsw[e]() to new guest access functions.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Reviewed-by: Thomas Huth <thuth@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
2014-04-22 13:24:45 +02:00
Cornelia Huck
2f32d4ea28 KVM: s390: reinject io interrupt on tpi failure
The tpi instruction should be suppressed on addressing and protection
exceptions, so we need to re-inject the dequeued io interrupt in that
case.

Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
2014-04-22 13:24:45 +02:00
Heiko Carstens
4799b557c9 KVM: s390: convert handle_tpi()
Convert handle_tpi() to new guest access functions.

The code now sets up a structure which is copied with a single call to
guest space instead of issuing several separate guest access calls.
This is necessary since the to be copied data may cross a page boundary.
If a protection exception happens while accessing any of the pages, the
instruction is suppressed and may not have modified any memory contents.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
2014-04-22 13:24:44 +02:00
Heiko Carstens
ef23e7790e KVM: s390: convert handle_test_block()
Convert handle_test_block() to new guest access functions.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Reviewed-by: Thomas Huth <thuth@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
2014-04-22 13:24:44 +02:00
Heiko Carstens
8b96de0e03 KVM: s390: convert handle_store_cpu_address()
Convert handle_store_cpu_address() to new guest access functions.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Reviewed-by: Thomas Huth <thuth@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
2014-04-22 13:24:43 +02:00
Heiko Carstens
f748f4a7ec KVM: s390: convert handle_store_prefix()
Convert handle_store_prefix() to new guest access functions.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Reviewed-by: Thomas Huth <thuth@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
2014-04-22 13:24:43 +02:00
Heiko Carstens
0e7a3f9405 KVM: s390: convert handle_set_clock()
Convert handle_set_clock() to new guest access functions.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Reviewed-by: Thomas Huth <thuth@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
2014-04-22 13:24:42 +02:00
Heiko Carstens
665170cb47 KVM: s390: convert __sigp_set_prefix()/handle_set_prefix()
Convert __sigp_set_prefix() and handle_set_prefix() to new guest
access functions.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Reviewed-by: Thomas Huth <thuth@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
2014-04-22 13:24:42 +02:00
Heiko Carstens
d0bce6054a KVM: s390: convert kvm_s390_store_status_unloaded()
Convert kvm_s390_store_status_unloaded() to new guest access functions.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Reviewed-by: Thomas Huth <thuth@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
2014-04-22 13:24:41 +02:00
Heiko Carstens
0040e7d20f KVM: s390: convert handle_prog()
Convert handle_prog() to new guest access functions.
Also make the code a bit more readable and look at the return code
of write_guest_lc() which was missing before.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
2014-04-22 13:24:41 +02:00
Heiko Carstens
81480cc19c KVM: s390: convert pfault code
Convert pfault code to new guest access functions.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Reviewed-by: Dominik Dingel <dingel@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
2014-04-22 13:24:40 +02:00
Heiko Carstens
0f9701c6c2 KVM: s390: convert handle_stfl()
Convert handle_stfl() to new guest access functions.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Reviewed-by: Thomas Huth <thuth@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
2014-04-22 13:24:40 +02:00
Jens Freimann
1a03b76422 KVM: s390: convert local irqs in __do_deliver_interrupt()
Convert local irqs in __do_deliver_interrupt() to new guest
access functions.

Signed-off-by: Jens Freimann <jfrei@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
2014-04-22 13:24:40 +02:00
Heiko Carstens
7988276df7 KVM: s390: convert __do_deliver_interrupt()
Convert __do_deliver_interrupt() to new guest access functions.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Reviewed-by: Thomas Huth <thuth@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
2014-04-22 13:24:39 +02:00
Heiko Carstens
8a242234b4 KVM: s390: make use of ipte lock
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Reviewed-by: Thomas Huth <thuth@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
2014-04-22 13:24:39 +02:00
Heiko Carstens
217a440683 KVM: s390/sclp: correctly set eca siif bit
Check if siif is available before setting.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Reviewed-by: Thomas Huth <thuth@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
2014-04-22 13:24:38 +02:00
Heiko Carstens
2293897805 KVM: s390: add architecture compliant guest access functions
The new guest memory access function write_guest() and read_guest() can be
used to access guest memory in an architecture compliant way.
These functions will look at the vcpu's PSW and select the correct address
space for memory access and also perform correct address wrap around.
In case DAT is turned on, page tables will be walked otherwise access will
happen to real or absolute memory.

Any access exception will be recognized and exception data will be stored
in the vcpu's kvm_vcpu_arch.pgm member. Subsequently an exception can be
injected if necessary.

Missing are:
- key protection checks
- access register mode support
- program event recording support

This patch also adds write_guest_real(), read_guest_real(),
write_guest_absolute() and read_guest_absolute() guest functions which can
be used to access real and absolute storage. These functions currently do
not perform any access checks, since there is no use case (yet?).

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Reviewed-by: Thomas Huth <thuth@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
2014-04-22 13:24:38 +02:00
Heiko Carstens
d95fb12ff4 KVM: s390: add lowcore access functions
put_guest_lc, read_guest_lc and write_guest_lc are guest access
functions which shall only be used to access the lowcore of a vcpu.
These functions should be used for e.g. interrupt handlers where no
guest memory access protection facilities, like key or low address
protection, are applicable.

At a later point guest vcpu lowcore access should happen via pinned
prefix pages, so that these pages can be accessed directly via the
kernel mapping. All of these *_lc functions can be removed then.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Reviewed-by: Thomas Huth <thuth@linux.vnet.ibm.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
2014-04-22 13:24:37 +02:00
Heiko Carstens
1b0462e574 KVM: s390: add 'pgm' member to kvm_vcpu_arch and helper function
Add a 'struct kvm_s390_pgm_info pgm' member to kvm_vcpu_arch. This
structure will be used if during instruction emulation in the context
of a vcpu exception data needs to be stored somewhere.

Also add a helper function kvm_s390_inject_prog_cond() which can inject
vcpu's last exception if needed.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
2014-04-22 13:24:37 +02:00
Heiko Carstens
072c9878ee KVM: s390: add kvm_s390_logical_to_effective() helper
Add kvm_s390_logical_to_effective() helper which converts a guest vcpu's
logical storage address to a guest vcpu effective address by applying the
rules of the vcpu's addressing mode defined by PSW bits 31 and 32
(extendended and basic addressing mode).
Depending on the vcpu's addressing mode the upper 40 bits (24 bit addressing
mode), 33 bits (31 bit addressing mode) or no bits (64 bit addressing mode)
will be zeroed and the remaining bits will be returned.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
2014-04-22 13:24:36 +02:00
Heiko Carstens
5f4e87a227 s390/ctl_reg: add union type for control register 0
Add 'union ctlreg0_bits' to easily allow setting and testing bits of
control register 0 bits.
This patch only adds the bits needed for the new guest access functions.
Other bits and control registers can be added when needed.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Reviewed-by: Thomas Huth <thuth@linux.vnet.ibm.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
2014-04-22 13:24:36 +02:00
Heiko Carstens
1365632bde s390/ptrace: add struct psw and accessor function
Introduce a 'struct psw' which makes it easier to decode and test if
certain bits in a psw are set or are not set.
In addition also add a 'psw_bits()' helper define which allows to
directly modify and test a psw_t structure. E.g.

psw_t psw;
psw_bits(psw).t = 1; /* set dat bit */

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Reviewed-by: Thomas Huth <thuth@linux.vnet.ibm.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
2014-04-22 13:24:36 +02:00
Heiko Carstens
280ef0f1f9 KVM: s390: export test_vfacility()
Make test_vfacility() available for other files. This is needed for the
new guest access functions, which test if certain facilities are available
for a guest.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
2014-04-22 13:24:35 +02:00
Heiko Carstens
dfeec843fb KVM: add kvm_is_error_gpa() helper
It's quite common (in the s390 guest access code) to test if a guest
physical address points to a valid guest memory area or not.
So add a simple helper function in common code, since this might be
of interest for other architectures as well.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Reviewed-by: Thomas Huth <thuth@linux.vnet.ibm.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
2014-04-22 13:24:35 +02:00
Jens Freimann
bcd846837c KVM: s390: allow injecting every kind of interrupt
Add a new data structure and function that allows to inject
all kinds of interrupt as defined in the PoP

Signed-off-by: Jens Freimann <jfrei@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
2014-04-22 13:24:34 +02:00
Dominik Dingel
4f718eab26 KVM: s390: Exploiting generic userspace interface for cmma
To enable CMMA and to reset its state we use the vm kvm_device ioctls,
encapsulating attributes within the KVM_S390_VM_MEM_CTRL group.

Signed-off-by: Dominik Dingel <dingel@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
2014-04-22 13:24:32 +02:00
Dominik Dingel
b31605c12f KVM: s390: make cmma usage conditionally
When userspace reset the guest without notifying kvm, the CMMA state
of the pages might be unused, resulting in guest data corruption.
To avoid this, CMMA must be enabled only if userspace understands
the implications.

CMMA must be enabled before vCPU creation. It can't be switched off
once enabled.  All subsequently created vCPUs will be enabled for
CMMA according to the CMMA state of the VM.

Signed-off-by: Dominik Dingel <dingel@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
[remove now unnecessary calls to page_table_reset_pgste]
2014-04-22 13:24:13 +02:00
Dominik Dingel
f206165620 KVM: s390: Per-vm kvm device controls
We sometimes need to get/set attributes specific to a virtual machine
and so need something else than ONE_REG.

Let's copy the KVM_DEVICE approach, and define the respective ioctls
for the vm file descriptor.

Signed-off-by: Dominik Dingel <dingel@linux.vnet.ibm.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Acked-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
2014-04-22 13:24:12 +02:00
Jason J. Herne
15f36ebd34 KVM: s390: Add proper dirty bitmap support to S390 kvm.
Replace the kvm_s390_sync_dirty_log() stub with code to construct the KVM
dirty_bitmap from S390 memory change bits.  Also add code to properly clear
the dirty_bitmap size when clearing the bitmap.

Signed-off-by: Jason J. Herne <jjherne@us.ibm.com>
CC: Dominik Dingel <dingel@linux.vnet.ibm.com>
[Dominik Dingel: use gmap_test_and_clear_dirty, locking fixes]
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
2014-04-22 09:36:28 +02:00
Dominik Dingel
a0bf4f149b KVM: s390/mm: new gmap_test_and_clear_dirty function
For live migration kvm needs to test and clear the dirty bit of guest pages.

That for is ptep_test_and_clear_user_dirty, to be sure we are not racing with
other code, we protect the pte. This needs to be done within
the architecture memory management code.

Signed-off-by: Dominik Dingel <dingel@linux.vnet.ibm.com>
Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
2014-04-22 09:36:27 +02:00
Martin Schwidefsky
0a61b222df KVM: s390/mm: use software dirty bit detection for user dirty tracking
Switch the user dirty bit detection used for migration from the hardware
provided host change-bit in the pgste to a fault based detection method.
This reduced the dependency of the host from the storage key to a point
where it becomes possible to enable the RCP bypass for KVM guests.

The fault based dirty detection will only indicate changes caused
by accesses via the guest address space. The hardware based method
can detect all changes, even those caused by I/O or accesses via the
kernel page table. The KVM/qemu code needs to take this into account.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Dominik Dingel <dingel@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
2014-04-22 09:36:26 +02:00
Dominik Dingel
693ffc0802 KVM: s390: Don't enable skeys by default
The first invocation of storage key operations on a given cpu will be intercepted.

On these intercepts we will enable storage keys for the guest and remove the
previously added intercepts.

Signed-off-by: Dominik Dingel <dingel@linux.vnet.ibm.com>
Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
2014-04-22 09:36:26 +02:00
Dominik Dingel
934bc131ef KVM: s390: Allow skeys to be enabled for the current process
Introduce a new function s390_enable_skey(), which enables storage key
handling via setting the use_skey flag in the mmu context.

This function is only useful within the context of kvm.

Note that enabling storage keys will cause a one-time hickup when
walking the page table; however, it saves us special effort for cases
like clear reset while making it possible for us to be architecture
conform.

s390_enable_skey() takes the page table lock to prevent reseting
storage keys triggered from multiple vcpus.

Signed-off-by: Dominik Dingel <dingel@linux.vnet.ibm.com>
Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
2014-04-22 09:36:25 +02:00
Dominik Dingel
d4cb11340b KVM: s390: Clear storage keys
page_table_reset_pgste() already does a complete page table walk to
reset the pgste. Enhance it to initialize the storage keys to
PAGE_DEFAULT_KEY if requested by the caller. This will be used
for lazy storage key handling. Also provide an empty stub for
!CONFIG_PGSTE

Lets adopt the current code (diag 308) to not clear the keys.

Signed-off-by: Dominik Dingel <dingel@linux.vnet.ibm.com>
Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
2014-04-22 09:36:24 +02:00
Dominik Dingel
65eef33550 KVM: s390: Adding skey bit to mmu context
For lazy storage key handling, we need a mechanism to track if the
process ever issued a storage key operation.

This patch adds the basic infrastructure for making the storage
key handling optional, but still leaves it enabled for now by default.

Signed-off-by: Dominik Dingel <dingel@linux.vnet.ibm.com>
Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
2014-04-22 09:36:23 +02:00
Linus Torvalds
0f689a33ad Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux
Pull s390 patches from Martin Schwidefsky:
 "An update to the oops output with additional information about the
  crash.  The renameat2 system call is enabled.  Two patches in regard
  to the PTR_ERR_OR_ZERO cleanup.  And a bunch of bug fixes"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux:
  s390/sclp_cmd: replace PTR_RET with PTR_ERR_OR_ZERO
  s390/sclp: replace PTR_RET with PTR_ERR_OR_ZERO
  s390/sclp_vt220: Fix kernel panic due to early terminal input
  s390/compat: fix typo
  s390/uaccess: fix possible register corruption in strnlen_user_srst()
  s390: add 31 bit warning message
  s390: wire up sys_renameat2
  s390: show_registers() should not map user space addresses to kernel symbols
  s390/mm: print control registers and page table walk on crash
  s390/smp: fix smp_stop_cpu() for !CONFIG_SMP
  s390: fix control register update
2014-04-16 11:28:25 -07:00
Linus Torvalds
7d38cc0290 Small workaround for a rare, but annoying, erratum
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Merge tag 'please-pull-ia64-erratum' of git://git.kernel.org/pub/scm/linux/kernel/git/aegl/linux

Pull itanium erratum fix from Tony Luck:
 "Small workaround for a rare, but annoying, erratum #237"

* tag 'please-pull-ia64-erratum' of git://git.kernel.org/pub/scm/linux/kernel/git/aegl/linux:
  [IA64] Change default PSR.ac from '1' to '0' (Fix erratum #237)
2014-04-16 11:22:45 -07:00
Tony Luck
c0b5a64d93 [IA64] Change default PSR.ac from '1' to '0' (Fix erratum #237)
April 2014 Itanium processor specification update:

http://www.intel.com/content/www/us/en/processors/itanium/itanium-specification-update.html

describes this erratum:

=========================================================================
237. Under a complex set of conditions, store to load forwarding for a
sub 8-byte load may complete incorrectly

Problem: A load instruction may complete incorrectly when a code sequence
using 4-byte or smaller load and store operations to the same address
is executed in combination with specific timing of all the following
concurrent conditions: store to load forwarding, alignment checking
enabled, a mis-predicted branch, and complex cache utilization activity.

Implication: The affected sub 8-byte instruction may complete
incorrectly resulting in unpredictable system behavior. There is an
extremely low probability of exposure due to the significant number of
complex microarchitectural concurrent conditions required to encounter
the erratum.

Workaround: Set PSR.ac = 0 to completely avoid the erratum. Disabling
Hyper-Threading will significantly reduce exposure to the conditions
that contribute to encountering the erratum.

Status: See the Summary Table of Changes for the affected steppings.
=========================================================================

[Table of changes essentially lists all models from McKinley to Tukwila]

The PSR.ac bit controls whether the processor will always generate
an unaligned reference trap (0x5a00) for a misaligned data access
(when PSR.ac=1) or if it will let the access succeed when running
on a cpu that implements logic to handle some unaligned accesses.

Way back in 2008 in commit b704882e70
  [IA64] Rationalize kernel mode alignment checking
we made the decision to always enable strict checking. We were
already doing so in trap/interrupt context because the common
preamble code set this bit - but the rest of supervisor code
(and by inheritance user code) ran with PSR.ac=0.

We now reverse that decision and set PSR.ac=0 everywhere in the
kernel (also inherited by user processes). This will avoid the
erratum using the method described in the Itanium specification
update.  Net effect for users is that the processor will handle
unaligned access when it can (typically with a tiny performance
bubble in the pipeline ... but much less invasive than taking a
trap and having the OS perform the access).

Signed-off-by: Tony Luck <tony.luck@intel.com>
2014-04-16 10:20:34 -07:00