This causes all non-NMI, non-double-fault kernel entries from
userspace to run on the normal kernel stack.  Double-fault is
exempt to minimize confusion if we double-fault directly from
userspace due to a bad kernel stack.

This is, suprisingly, simpler and shorter than the current code.  It
removes the IMO rather frightening paranoid_userspace path, and it
make sync_regs much simpler.

There is no risk of stack overflow due to this change -- the kernel
stack that we switch to is empty.

This will also enable us to create non-atomic sections within
machine checks from userspace, which will simplify memory failure
handling.  It will also allow the upcoming fsgsbase code to be
simplified, because it doesn't need to worry about usergs when
scheduling in paranoid_exit, as that code no longer exists.

Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Tony Luck <tony.luck@intel.com>
Acked-by: NBorislav Petkov <bp@alien8.de>
Signed-off-by: NAndy Lutomirski <luto@amacapital.net>

There are no users of this symbol left.
Reported-by: NPaul Bolle <pebolle@tiscali.nl>
Signed-off-by: NJesper Nilsson <jesper.nilsson@axis.com>

Move pinmux alloc/dealloc code into functions that don't take
the spinlock so we can use from code that has the spinlock already.

CRISv32 has no working SMP, so spinlocks becomes a NOP,
so deadlock was never seen.
Signed-off-by: NJesper Nilsson <jesper.nilsson@axis.com>

Fixes compile error on allmodconfig.
Signed-off-by: NJesper Nilsson <jesper.nilsson@axis.com>

Signed-off-by: NJesper Nilsson <jesper.nilsson@axis.com>

Also, print kernel version on oops.
Signed-off-by: NJesper Nilsson <jesper.nilsson@axis.com>

Drop i2c_init from this header, it was declared non-static here,
but static in the C-file.
Signed-off-by: NJesper Nilsson <jesper.nilsson@axis.com>

Make driver possible to load as a module and try to handle
locking better.
Signed-off-by: NJesper Nilsson <jesper.nilsson@axis.com>

- Add free_initrd_mem as found by Guenter Roeck <linux@roeck-us.net>
- Add free_init_pages
- Export empty_zero_page symbol
Signed-off-by: NJesper Nilsson <jesper.nilsson@axis.com>

Don't enter watchdog handling if we're already in watchdog handling.

Also some minor formatting tweaks.
Signed-off-by: NJesper Nilsson <jesper.nilsson@axis.com>

strcmp was lost when all other string functions were removed,
but we still have an optimized version for this on CRISv32,
so any driver built as a module would not have access to this symbol.

In a similar manner, we had optimized versions of
csum_partial_copy_from_user and __do_clear_user
but no exported symbols for them, breaking bunch of other drivers
when built as a module.

At the same time, move EXPORT_SYMBOL(__copy_user) and
EXPORT_SYMBOL(__copy_user_zeroing) C-files so it's
located together with the function definition.
Signed-off-by: NJesper Nilsson <jesper.nilsson@axis.com>

Signed-off-by: NJesper Nilsson <jesper.nilsson@axis.com>

Fix headers_install by adjusting the path to arch files.
And delete unused Kbuild file.
Drop special handling of cris in the headers.sh script
as a nice side-effect.
Signed-off-by: NSam Ravnborg <sam@ravnborg.org>
Cc: Mikael Starvik <starvik@axis.com>
Cc: David Howells <dhowells@redhat.com>
Signed-off-by: NJesper Nilsson <jesper.nilsson@axis.com>

Fixes the following compile error.

arch/cris/arch-v32/kernel/time.c: In function 'reset_watchdog':
arch/cris/arch-v32/kernel/time.c:121:2:
        error: implicit declaration of function 'global_page_state'
Signed-off-by: NGuenter Roeck <linux@roeck-us.net>
Signed-off-by: NJesper Nilsson <jesper.nilsson@axis.com>

File was already deleted.
Signed-off-by: NJesper Nilsson <jesper.nilsson@axis.com>

Having switched over all of the users of CONFIG_PM_RUNTIME to use
CONFIG_PM directly, turn the latter into a user-selectable option
and drop the former entirely from the tree.
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: NUlf Hansson <ulf.hansson@linaro.org>
Acked-by: NKevin Hilman <khilman@linaro.org>

Commit 69111bac ("powerpc: Replace __get_cpu_var uses") introduced
compile breakage to the e500 target by introducing invalid automatically
created C syntax.

Fix up the breakage and make the code compile again.
Signed-off-by: NAlexander Graf <agraf@suse.de>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Load balancing can be triggered in the critical sections protected by
srmmu_context_spinlock in destroy_context() and switch_mm() and can hang
the cpu waiting for the rq lock of another cpu that in turn has called
switch_mm hangning on srmmu_context_spinlock leading to deadlock.

So, disable interrupt while taking srmmu_context_spinlock in
destroy_context() and switch_mm() so we don't deadlock.

See also commit 77b838fa ("[SPARC64]: destroy_context() needs to disable
interrupts.")
Signed-off-by: NAndreas Larsson <andreas@gaisler.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

It turns out that there's a lurking ABI issue.  GCC, when
compiling this in a 32-bit program:

struct user_desc desc = {
	.entry_number    = idx,
	.base_addr       = base,
	.limit           = 0xfffff,
	.seg_32bit       = 1,
	.contents        = 0, /* Data, grow-up */
	.read_exec_only  = 0,
	.limit_in_pages  = 1,
	.seg_not_present = 0,
	.useable         = 0,
};

will leave .lm uninitialized.  This means that anything in the
kernel that reads user_desc.lm for 32-bit tasks is unreliable.

Revert the .lm check in set_thread_area().  The value never did
anything in the first place.

Fixes: 0e58af4e ("x86/tls: Disallow unusual TLS segments")
Signed-off-by: NAndy Lutomirski <luto@amacapital.net>
Acked-by: NThomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org # Only if 0e58af4e is backported
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/d7875b60e28c512f6a6fc0baf5714d58e7eaadbb.1418856405.git.luto@amacapital.netSigned-off-by: NIngo Molnar <mingo@kernel.org>

Starting with POWER8, the subcore logic relies on all threads of a core
being booted so that they can participate in split mode switches. So on
those machines we ignore the smt_enabled_at_boot setting (smt-enabled on
the kernel command line).
Signed-off-by: NGreg Kurz <gkurz@linux.vnet.ibm.com>
[mpe: Update comment and change log to be more precise]
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

ACCESS_ONCE does not work reliably on non-scalar types. For
example gcc 4.6 and 4.7 might remove the volatile tag for such
accesses during the SRA (scalar replacement of aggregates) step
(https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58145)

Commit 1365039d ("KVM: s390: Fix ipte locking") replace
ACCESS_ONCE with barriers. Lets use READ_ONCE instead.
Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>
Acked-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>

ACCESS_ONCE does not work reliably on non-scalar types. For
example gcc 4.6 and 4.7 might remove the volatile tag for such
accesses during the SRA (scalar replacement of aggregates) step
(https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58145)

Change the spinlock code to replace ACCESS_ONCE with READ_ONCE.
Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>
Acked-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>

ACCESS_ONCE does not work reliably on non-scalar types. For
example gcc 4.6 and 4.7 might remove the volatile tag for such
accesses during the SRA (scalar replacement of aggregates) step
(https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58145)

Change the spinlock code to replace ACCESS_ONCE with READ_ONCE.
Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>
Acked-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>

ACCESS_ONCE does not work reliably on non-scalar types. For
example gcc 4.6 and 4.7 might remove the volatile tag for such
accesses during the SRA (scalar replacement of aggregates) step
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58145)

Change the gup code to replace ACCESS_ONCE with READ_ONCE.
Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>
Acked-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>

ACCESS_ONCE does not work reliably on non-scalar types. For
example gcc 4.6 and 4.7 might remove the volatile tag for such
accesses during the SRA (scalar replacement of aggregates) step
(https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58145)

Change the gup code to replace ACCESS_ONCE with READ_ONCE.
Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>
Acked-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>

ACCESS_ONCE does not work reliably on non-scalar types. For
example gcc 4.6 and 4.7 might remove the volatile tag for such
accesses during the SRA (scalar replacement of aggregates) step
(https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58145)

Change the spinlock code to replace ACCESS_ONCE with READ_ONCE.
Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>
Acked-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>

They are not used anymore by IA64, move them away.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

At the moment, if p and x are both of the same bitwise type
(eg. __le32), get_user(x, p) produces a sparse warning.

This is because *p is loaded into a long then cast back to typeof(*p).

When typeof(*p) is a bitwise type (which is uncommon), such a cast needs
__force, otherwise sparse produces a warning.

For non-bitwise types __force should have no effect, and should not hide
any legitimate errors.

Note that we are casting to typeof(*p) not typeof(x). Even with the
cast, if x and *p are of different types we should get the warning, so I
think we are not loosing the ability to detect any actual errors.

virtio would like to use bitwise types with get_user() so fix these
spurious warnings by adding __force.
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
[mpe: Fill in changelog with more details]
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

The in-kernel XICS emulation is faster than doing it all in QEMU
and it has got a lot of testing, so enable it by default.
Signed-off-by: NAnton Blanchard <anton@samba.org>
Signed-off-by: NPaul Mackerras <paulus@samba.org>
Signed-off-by: NAlexander Graf <agraf@suse.de>

My commit 26178ec1 ("x86: mm: consolidate VM_FAULT_RETRY handling")
had a really stupid typo: the FAULT_FLAG_USER bit is in the 'flags'
variable, not the 'fault' variable. Duh,

The one silver lining in this is that Dave finding this at least
confirms that trinity actually triggers this special path easily, in a
way normal use does not.
Reported-by: NDave Jones <davej@redhat.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Currently the H_CONFER hcall is implemented in kernel virtual mode,
meaning that whenever a guest thread does an H_CONFER, all the threads
in that virtual core have to exit the guest.  This is bad for
performance because it interrupts the other threads even if they
are doing useful work.

The H_CONFER hcall is called by a guest VCPU when it is spinning on a
spinlock and it detects that the spinlock is held by a guest VCPU that
is currently not running on a physical CPU.  The idea is to give this
VCPU's time slice to the holder VCPU so that it can make progress
towards releasing the lock.

To avoid having the other threads exit the guest unnecessarily,
we add a real-mode implementation of H_CONFER that checks whether
the other threads are doing anything.  If all the other threads
are idle (i.e. in H_CEDE) or trying to confer (i.e. in H_CONFER),
it returns H_TOO_HARD which causes a guest exit and allows the
H_CONFER to be handled in virtual mode.

Otherwise it spins for a short time (up to 10 microseconds) to give
other threads the chance to observe that this thread is trying to
confer.  The spin loop also terminates when any thread exits the guest
or when all other threads are idle or trying to confer.  If the
timeout is reached, the H_CONFER returns H_SUCCESS.  In this case the
guest VCPU will recheck the spinlock word and most likely call
H_CONFER again.

This also improves the implementation of the H_CONFER virtual mode
handler.  If the VCPU is part of a virtual core (vcore) which is
runnable, there will be a 'runner' VCPU which has taken responsibility
for running the vcore.  In this case we yield to the runner VCPU
rather than the target VCPU.

We also introduce a check on the target VCPU's yield count: if it
differs from the yield count passed to H_CONFER, the target VCPU
has run since H_CONFER was called and may have already released
the lock.  This check is required by PAPR.
Signed-off-by: NSam Bobroff <sam.bobroff@au1.ibm.com>
Signed-off-by: NPaul Mackerras <paulus@samba.org>
Signed-off-by: NAlexander Graf <agraf@suse.de>

There are two ways in which a guest instruction can be obtained from
the guest in the guest exit code in book3s_hv_rmhandlers.S.  If the
exit was caused by a Hypervisor Emulation interrupt (i.e. an illegal
instruction), the offending instruction is in the HEIR register
(Hypervisor Emulation Instruction Register).  If the exit was caused
by a load or store to an emulated MMIO device, we load the instruction
from the guest by turning data relocation on and loading the instruction
with an lwz instruction.

Unfortunately, in the case where the guest has opposite endianness to
the host, these two methods give results of different endianness, but
both get put into vcpu->arch.last_inst.  The HEIR value has been loaded
using guest endianness, whereas the lwz will load the instruction using
host endianness.  The rest of the code that uses vcpu->arch.last_inst
assumes it was loaded using host endianness.

To fix this, we define a new vcpu field to store the HEIR value.  Then,
in kvmppc_handle_exit_hv(), we transfer the value from this new field to
vcpu->arch.last_inst, doing a byte-swap if the guest and host endianness
differ.
Signed-off-by: NPaul Mackerras <paulus@samba.org>
Signed-off-by: NAlexander Graf <agraf@suse.de>

This removes the code that was added to enable HV KVM to work
on PPC970 processors.  The PPC970 is an old CPU that doesn't
support virtualizing guest memory.  Removing PPC970 support also
lets us remove the code for allocating and managing contiguous
real-mode areas, the code for the !kvm->arch.using_mmu_notifiers
case, the code for pinning pages of guest memory when first
accessed and keeping track of which pages have been pinned, and
the code for handling H_ENTER hypercalls in virtual mode.

Book3S HV KVM is now supported only on POWER7 and POWER8 processors.
The KVM_CAP_PPC_RMA capability now always returns 0.
Signed-off-by: NPaul Mackerras <paulus@samba.org>
Signed-off-by: NAlexander Graf <agraf@suse.de>

This patch adds trace points in the guest entry and exit code and also
for exceptions handled by the host in kernel mode - hypercalls and page
faults. The new events are added to /sys/kernel/debug/tracing/events
under a new subsystem called kvm_hv.
Acked-by: NPaul Mackerras <paulus@samba.org>
Signed-off-by: NSuresh Warrier <warrier@linux.vnet.ibm.com>
Signed-off-by: NAlexander Graf <agraf@suse.de>

Currently the calculations of stolen time for PPC Book3S HV guests
uses fields in both the vcpu struct and the kvmppc_vcore struct.  The
fields in the kvmppc_vcore struct are protected by the
vcpu->arch.tbacct_lock of the vcpu that has taken responsibility for
running the virtual core.  This works correctly but confuses lockdep,
because it sees that the code takes the tbacct_lock for a vcpu in
kvmppc_remove_runnable() and then takes another vcpu's tbacct_lock in
vcore_stolen_time(), and it thinks there is a possibility of deadlock,
causing it to print reports like this:

=============================================
[ INFO: possible recursive locking detected ]
3.18.0-rc7-kvm-00016-g8db4bc6 #89 Not tainted
---------------------------------------------
qemu-system-ppc/6188 is trying to acquire lock:
 (&(&vcpu->arch.tbacct_lock)->rlock){......}, at: [<d00000000ecb1fe8>] .vcore_stolen_time+0x48/0xd0 [kvm_hv]

but task is already holding lock:
 (&(&vcpu->arch.tbacct_lock)->rlock){......}, at: [<d00000000ecb25a0>] .kvmppc_remove_runnable.part.3+0x30/0xd0 [kvm_hv]

other info that might help us debug this:
 Possible unsafe locking scenario:

       CPU0
       ----
  lock(&(&vcpu->arch.tbacct_lock)->rlock);
  lock(&(&vcpu->arch.tbacct_lock)->rlock);

 *** DEADLOCK ***

 May be due to missing lock nesting notation

3 locks held by qemu-system-ppc/6188:
 #0:  (&vcpu->mutex){+.+.+.}, at: [<d00000000eb93f98>] .vcpu_load+0x28/0xe0 [kvm]
 #1:  (&(&vcore->lock)->rlock){+.+...}, at: [<d00000000ecb41b0>] .kvmppc_vcpu_run_hv+0x530/0x1530 [kvm_hv]
 #2:  (&(&vcpu->arch.tbacct_lock)->rlock){......}, at: [<d00000000ecb25a0>] .kvmppc_remove_runnable.part.3+0x30/0xd0 [kvm_hv]

stack backtrace:
CPU: 40 PID: 6188 Comm: qemu-system-ppc Not tainted 3.18.0-rc7-kvm-00016-g8db4bc6 #89
Call Trace:
[c000000b2754f3f0] [c000000000b31b6c] .dump_stack+0x88/0xb4 (unreliable)
[c000000b2754f470] [c0000000000faeb8] .__lock_acquire+0x1878/0x2190
[c000000b2754f600] [c0000000000fbf0c] .lock_acquire+0xcc/0x1a0
[c000000b2754f6d0] [c000000000b2954c] ._raw_spin_lock_irq+0x4c/0x70
[c000000b2754f760] [d00000000ecb1fe8] .vcore_stolen_time+0x48/0xd0 [kvm_hv]
[c000000b2754f7f0] [d00000000ecb25b4] .kvmppc_remove_runnable.part.3+0x44/0xd0 [kvm_hv]
[c000000b2754f880] [d00000000ecb43ec] .kvmppc_vcpu_run_hv+0x76c/0x1530 [kvm_hv]
[c000000b2754f9f0] [d00000000eb9f46c] .kvmppc_vcpu_run+0x2c/0x40 [kvm]
[c000000b2754fa60] [d00000000eb9c9a4] .kvm_arch_vcpu_ioctl_run+0x54/0x160 [kvm]
[c000000b2754faf0] [d00000000eb94538] .kvm_vcpu_ioctl+0x498/0x760 [kvm]
[c000000b2754fcb0] [c000000000267eb4] .do_vfs_ioctl+0x444/0x770
[c000000b2754fd90] [c0000000002682a4] .SyS_ioctl+0xc4/0xe0
[c000000b2754fe30] [c0000000000092e4] syscall_exit+0x0/0x98

In order to make the locking easier to analyse, we change the code to
use a spinlock in the kvmppc_vcore struct to protect the stolen_tb and
preempt_tb fields.  This lock needs to be an irq-safe lock since it is
used in the kvmppc_core_vcpu_load_hv() and kvmppc_core_vcpu_put_hv()
functions, which are called with the scheduler rq lock held, which is
an irq-safe lock.
Signed-off-by: NPaul Mackerras <paulus@samba.org>
Signed-off-by: NAlexander Graf <agraf@suse.de>

Remove the function inst_set_field() that is not used anywhere.

This was partially found by using a static code analysis program called cppcheck.
Signed-off-by: NRickard Strandqvist <rickard_strandqvist@spectrumdigital.se>
Signed-off-by: NAlexander Graf <agraf@suse.de>

Remove the function get_fpr_index() that is not used anywhere.

This was partially found by using a static code analysis program called cppcheck.
Signed-off-by: NRickard Strandqvist <rickard_strandqvist@spectrumdigital.se>
Signed-off-by: NAlexander Graf <agraf@suse.de>

Removes some functions that are not used anywhere:
kvmppc_core_load_guest_debugstate() kvmppc_core_load_host_debugstate()

This was partially found by using a static code analysis program called cppcheck.
Signed-off-by: NRickard Strandqvist <rickard_strandqvist@spectrumdigital.se>
Signed-off-by: NAlexander Graf <agraf@suse.de>

Remove the function sr_nx() that is not used anywhere.

This was partially found by using a static code analysis program called cppcheck.
Signed-off-by: NRickard Strandqvist <rickard_strandqvist@spectrumdigital.se>
Signed-off-by: NAlexander Graf <agraf@suse.de>

When running in non-cache coherent configuration the memory that was
allocated with dma_alloc_coherent() has a custom mapping and so there is no
1-to-1 relationship between the kernel virtual address and the PFN. This
means that virt_to_pfn() will not work correctly for those addresses and the
default mmap implementation in the form of dma_common_mmap() will map some
random, but not the requested, memory area.

Fix this by providing a custom mmap implementation that looks up the PFN
from the page table rather than using virt_to_pfn.
Signed-off-by: NLars-Peter Clausen <lars@metafoo.de>
Signed-off-by: NMichal Simek <michal.simek@xilinx.com>