Thinking about it, I can't find a real use case where we want
to block a VCPU and not kick it out of SIE. (except if we want
to do the same in batch for multiple VCPUs - but that's a micro
optimization)

So let's simply perform the exit_sie() calls directly when setting
the other magic block bits in the SIE.

Otherwise e.g. kvm_s390_set_tod_low() still has other VCPUs running
after that call, working with a wrong epoch.

Fixes: 27406cd5 ("KVM: s390: provide functions for blocking all CPUs")
Acked-by: NChristian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: NDavid Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>

Our implementation will never trigger interception code 12 as the
responsible setting is never enabled - and never will be.
The handler is dead code. Let's get rid of it.
Reviewed-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: NDavid Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>

This patch factors out the search for a floating irq destination
VCPU as well as the kicking of the found VCPU. The search is optimized
in the following ways:

1. stopped VCPUs can't take any floating interrupts, so try to find an
   operating one. We have to take care of the special case where all
   VCPUs are stopped and we don't have any valid destination.

2. use online_vcpus, not KVM_MAX_VCPU. This speeds up the search
   especially if KVM_MAX_VCPU is increased one day. As these VCPU
   objects are initialized prior to increasing online_vcpus, we can be
   sure that they exist.
Reviewed-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Reviewed-by: NDominik Dingel <dingel@linux.vnet.ibm.com>
Reviewed-by: NJens Freimann <jfrei@linux.vnet.ibm.com>
Signed-off-by: NDavid Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>

We can avoid checking guest control registers and guest PSW as well
as all the masking and calculations on the interrupt masks when
no interrupts are pending.

Also, the check for IRQ_PEND_COUNT can be removed, because we won't
enter the while loop if no interrupts are pending and invalid interrupt
types can't be injected.
Signed-off-by: NJens Freimann <jfrei@linux.vnet.ibm.com>
Reviewed-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Reviewed-by: NDominik Dingel <dingel@linux.vnet.ibm.com>
Acked-by: NChristian Borntraeger <borntraeger@de.ibm.com>

Some updates to the control blocks need to be done in a way that
ensures that no CPU is within SIE. Provide wrappers around the
s390_vcpu_block functions and adopt the TOD migration code to
update in a guaranteed fashion. Also rename these functions to
have the kvm_s390_ prefix as everything else.
Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: NDavid Hildenbrand <dahi@linux.vnet.ibm.com>

exit_sie_sync is used to kick CPUs out of SIE and prevent reentering at
any point in time. This is used to reload the prefix pages and to
set the IBS stuff in a way that guarantees that after this function
returns we are no longer in SIE. All current users trigger KVM requests.

The request must be set before we block the CPUs to avoid races. Let's
make this implicit by adding the request into a new function
kvm_s390_sync_requests that replaces exit_sie_sync and split out
s390_vcpu_block and s390_vcpu_unblock, that can be used to keep
CPUs out of SIE independent of requests.
Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: NDavid Hildenbrand <dahi@linux.vnet.ibm.com>
Reviewed-by: NCornelia Huck <cornelia.huck@de.ibm.com>

1. Enable EDAT2 in the list of KVM facilities

2. Handle 2G frames in pfmf instruction
If we support EDAT2, we may enable handling of 2G frames if not in 24
bit mode.

3. Enable EDAT2 in sie_block
If the EDAT2 facility is available we enable GED2 mode control in the
sie_block.
Reviewed-by: NDavid Hildenbrand <dahi@linux.vnet.ibm.com>
Reviewed-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Reviewed-by: NChristian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: NGuenther Hutzl <hutzl@linux.vnet.ibm.com>
Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>

We should only enable EDAT1 for the guest if the host actually supports
it and the cpu model for the guest has EDAT-1 enabled.
Reviewed-by: NDavid Hildenbrand <dahi@linux.vnet.ibm.com>
Reviewed-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Reviewed-by: NChristian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: NGuenther Hutzl <hutzl@linux.vnet.ibm.com>
Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>

The fast path for a sie exit is that no kvm reqest is pending.
Make an early check to skip all single bit checks.
Reviewed-by: NDavid Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>

Commit ea5f4969 ("KVM: s390: only one external call may be pending
at a time") introduced a bug on machines that don't have SIGP
interpretation facility installed.
The injection of an external call will now always fail with -EBUSY
(if none is already pending).

This leads to the following symptoms:
- An external call will be injected but with the wrong "src cpu id",
  as this id will not be remembered.
- The target vcpu will not be woken up, therefore the guest will hang if
  it cannot deal with unexpected failures of the SIGP EXTERNAL CALL
  instruction.
- If an external call is already pending, -EBUSY will not be reported.
Reviewed-by: NChristian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: NJens Freimann <jfrei@linux.vnet.ibm.com>
Signed-off-by: NDavid Hildenbrand <dahi@linux.vnet.ibm.com>
Cc: stable@vger.kernel.org # v4.0
Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>

Patches 7cba160a "powernv/cpuidle: Redesign idle states management"
and 77b54e9f "powernv/powerpc: Add winkle support for offline cpus"
use non-volatile condition registers (cr2, cr3 and cr4) early in the system
reset interrupt handler (system_reset_pSeries()) before it has been determined
if state loss has occurred. If state loss has not occurred, control returns via
the power7_wakeup_noloss() path which does not restore those condition
registers, leaving them corrupted.

Fix this by restoring the condition registers in the power7_wakeup_noloss()
case.

This is apparent when running a KVM guest on hardware that does not
support winkle or sleep and the guest makes use of secondary threads. In
practice this means Power7 machines, though some early unreleased Power8
machines may also be susceptible.

The secondary CPUs are taken off line before the guest is started and
they call pnv_smp_cpu_kill_self(). This checks support for sleep
states (in this case there is no support) and power7_nap() is called.

When the CPU is woken, power7_nap() returns and because the CPU is
still off line, the main while loop executes again. The sleep states
support test is executed again, but because the tested values cannot
have changed, the compiler has optimized the test away and instead we
rely on the result of the first test, which has been left in cr3
and/or cr4. With the result overwritten, the wrong branch is taken and
power7_winkle() is called on a CPU that does not support it, leading
to it stalling.

Fixes: 7cba160a ("powernv/cpuidle: Redesign idle states management")
Fixes: 77b54e9f ("powernv/powerpc: Add winkle support for offline cpus")
[mpe: Massage change log a bit more]
Signed-off-by: NSam Bobroff <sam.bobroff@au1.ibm.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

Commit 1c509148b ("powerpc/eeh: Do probe on pci_dn") probes EEH
devices in early stage, which is reasonable to pSeries platform.
However, it's wrong for PowerNV platform because the PE# isn't
determined until the resources (IO and MMIO) are assigned to
PE in hotplug case. So we have to delay probing EEH devices
for PowerNV platform until the PE# is assigned.

Fixes: ff57b454 ("powerpc/eeh: Do probe on pci_dn")
Signed-off-by: NGavin Shan <gwshan@linux.vnet.ibm.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

When asserting reset in pcibios_set_pcie_reset_state(), the PE
is enforced to (hardware) frozen state in order to drop unexpected
PCI transactions (except PCI config read/write) automatically by
hardware during reset, which would cause recursive EEH error.
However, the (software) frozen state EEH_PE_ISOLATED is missed.
When users get 0xFF from PCI config or MMIO read, EEH_PE_ISOLATED
is set in PE state retrival backend. Unfortunately, nobody (the
reset handler or the EEH recovery functinality in host) will clear
EEH_PE_ISOLATED when the PE has been passed through to guest.

The patch sets and clears EEH_PE_ISOLATED properly during reset
in function pcibios_set_pcie_reset_state() to fix the issue.

Fixes: 28158cd1 ("Enhance pcibios_set_pcie_reset_state()")
Reported-by: NCarol L. Soto <clsoto@us.ibm.com>
Signed-off-by: NGavin Shan <gwshan@linux.vnet.ibm.com>
Tested-by: NCarol L. Soto <clsoto@us.ibm.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

The incorrect ordering of operations during cpu dlpar add results in invalid
affinity for the cpu being added. The ibm,associativity property in the
device tree is populated with all zeroes for the added cpu which results in
invalid affinity mappings and all cpus appear to belong to node 0.

This occurs because rtas configure-connector is called prior to making the
rtas set-indicator calls. Phyp does not assign affinity information
for a cpu until the rtas set-indicator calls are made to set the isolation
and allocation state.

Correct the order of operations to make the rtas set-indicator
calls (done in dlpar_acquire_drc) before calling rtas configure-connector.

Fixes: 1a8061c4 ("powerpc/pseries: Add kernel based CPU DLPAR handling")
Signed-off-by: NNathan Fontenot <nfont@linux.vnet.ibm.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

With commit d5efd9cc ("arm64: pmu: add support for interrupt-affinity
property"), we print a warning when we find a PMU SPI with a missing
missing interrupt-affinity property in a pmu node. Unfortunately, we
pass the wrong (NULL) device node to of_node_full_name, resulting in
unhelpful messages such as:

 hw perfevents: Failed to parse <no-node>/interrupt-affinity[0]

This patch fixes the name to that of the pmu node.

Fixes: d5efd9cc (arm64: pmu: add support for interrupt-affinity property)
Acked-by: NMark Rutland <mark.rutland@arm.com>
Signed-off-by: NSuzuki K. Poulose <suzuki.poulose@arm.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>

PPIs are affine by nature, so the interrupt-affinity property is not
used and therefore we shouldn't print a warning in its absence.
Reported-by: NMaxime Ripard <maxime.ripard@free-electrons.com>
Reviewed-by: NMaxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>

This reverts commit feba4036.

Although the principle of this change is good, the implementation has a
few issues.

Firstly we can sometimes fail to abort a syscall because r12 may have
been clobbered by C code if we went down the virtual CPU accounting
path, or if syscall tracing was enabled.

Secondly we have decided that it is safer to abort the syscall even
earlier in the syscall entry path, so that we avoid the syscall tracing
path when we are transactional.

So that we have time to thoroughly test those changes we have decided to
revert this for this merge window and will merge the fixed version in
the next window.

NB. Rather than reverting the selftest we just drop tm-syscall from
TEST_PROGS so that it's not run by default.

Fixes: feba4036 ("powerpc/tm: Abort syscalls in active transactions")
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

__dma_alloc() does a PAGE_ALIGN() on the passed in size argument before
doing anything else. __dma_free() does not. And because it doesn't, it is
possible to leak memory should size not be an integer multiple of PAGE_SIZE.

The solution is to add a PAGE_ALIGN() to __dma_free() like is done in
__dma_alloc().

Additionally, this patch removes a redundant PAGE_ALIGN() from
__dma_alloc_coherent(), since __dma_alloc_coherent() can only be called
from __dma_alloc(), which already does a PAGE_ALIGN() before the call.

Cc: stable@vger.kernel.org
Acked-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NDean Nelson <dnelson@redhat.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>

Load the PowerNV platform pci controller ops into pci controllers
after all the operations are loaded into the platform ops struct, not
before.

Otherwise we aren't actually setting the ops properly which can break
IO for some devices.

Fixes: 65ebf4b6 ("powerpc/powernv: Move controller ops from ppc_md to controller_ops")
Reported-by: NGavin Shan <gwshan@linux.vnet.ibm.com>
Reviewed-by: NGavin Shan <gwshan@linux.vnet.ibm.com>
Signed-off-by: NDaniel Axtens <dja@axtens.net>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

Commit 34cb7954 "Convert ICS mutex lock to spin lock" added an
include of asm/spinlock.h, which does not work in the SMP=n case.

It should instead include linux/spinlock.h

Fixes: 34cb7954 ("KVM: PPC: Book3S HV: Convert ICS mutex lock to spin lock")
Acked-by: NPaul Mackerras <paulus@samba.org>
Reviewed-by: NAlexander Graf <agraf@suse.de>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

The code accidentally used cpu_isset() previously in one place
(though properly node_isset() elsewhere).
Signed-off-by: NChris Metcalf <cmetcalf@ezchip.com>

This reverts commits 0a4e6be9
and 80f7fdb1.

The task migration notifier was originally introduced in order to support
the pvclock vsyscall with non-synchronized TSC, but KVM only supports it
with synchronized TSC.  Hence, on KVM the race condition is only needed
due to a bad implementation on the host side, and even then it's so rare
that it's mostly theoretical.

As far as KVM is concerned it's possible to fix the host, avoiding the
additional complexity in the vDSO and the (re)introduction of the task
migration notifier.

Xen, on the other hand, hasn't yet implemented vsyscall support at
all, so we do not care about its plans for non-synchronized TSC.
Reported-by: NPeter Zijlstra <peterz@infradead.org>
Suggested-by: NMarcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

The kvmclock spec says that the host will increment a version field to
an odd number, then update stuff, then increment it to an even number.
The host is buggy and doesn't do this, and the result is observable
when one vcpu reads another vcpu's kvmclock data.

There's no good way for a guest kernel to keep its vdso from reading
a different vcpu's kvmclock data, but we don't need to care about
changing VCPUs as long as we read a consistent data from kvmclock.
(VCPU can change outside of this loop too, so it doesn't matter if we
return a value not fit for this VCPU.)

Based on a patch by Radim Krčmář.
Reviewed-by: NRadim Krčmář <rkrcmar@redhat.com>
Acked-by: NMarcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Buffers allocated by dma_alloc_coherent() are always zeroed on Alpha,
ARM (32bit), MIPS, PowerPC, x86/x86_64 and probably other architectures.
It turned out that some drivers rely on this 'feature'. Allocated buffer
might be also exposed to userspace with dma_mmap() call, so clearing it
is desired from security point of view to avoid exposing random memory
to userspace. This patch unifies dma_alloc_coherent() behavior on ARM64
architecture with other implementations by unconditionally zeroing
allocated buffer.

Cc: <stable@vger.kernel.org> # v3.14+
Signed-off-by: NMarek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>

Since several interrupt controllers including GIC support both edge and
level triggered interrupts, it's useful to provide that information in
/proc/interrupts even on ARM64 similar to ARM and PPC.

This is based on Geert Uytterhoeven's commit 7c07005e ("ARM: 8339/1:
Enable CONFIG_GENERIC_IRQ_SHOW_LEVEL")
Signed-off-by: NSudeep Holla <sudeep.holla@arm.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>

Commit 8053871d ("smp: Fix smp_call_function_single_async()
locking") introduced a call to smp_load_acquire() with a u16 argument,
but we only cared about u32 and u64 types in that function so far.
This resulted in a compiler warning fortunately, pointing at an
uninitialized use. Due to the implementation structure the compiler
misses that bug in the smp_store_release(), though.
Add the u16 and u8 variants using ldarh/stlrh and ldarb/stlrb,
respectively. Together with the compiletime_assert_atomic_type() check
this should cover all cases now.
Acked-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NAndre Przywara <andre.przywara@arm.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>

AMD CPUs don't reinitialize the SS descriptor on SYSRET, so SYSRET with
SS == 0 results in an invalid usermode state in which SS is apparently
equal to __USER_DS but causes #SS if used.

Work around the issue by setting SS to __KERNEL_DS __switch_to, thus
ensuring that SYSRET never happens with SS set to NULL.

This was exposed by a recent vDSO cleanup.

Fixes: e7d6eefa x86/vdso32/syscall.S: Do not load __USER32_DS to %ss
Signed-off-by: NAndy Lutomirski <luto@kernel.org>
Cc: Peter Anvin <hpa@zytor.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Denys Vlasenko <vda.linux@googlemail.com>
Cc: Brian Gerst <brgerst@gmail.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Commit cae2a173 ("x86: clean up/fix 'copy_in_user()' tail zeroing")
fixed the failure case tail zeroing of one special case of the x86-64
generic user-copy routine, namely when used for the user-to-user case
("copy_in_user()").

But in the process it broke an even more unusual case: using the user
copy routine for kernel-to-kernel copying.

Now, normally kernel-kernel copies are obviously done using memcpy(),
but we have a couple of special cases when we use the user-copy
functions.  One is when we pass a kernel buffer to a regular user-buffer
routine, using set_fs(KERNEL_DS).  That's a "normal" case, and continued
to work fine, because it never takes any faults (with the possible
exception of a silent and successful vmalloc fault).

But Jan Beulich pointed out another, very unusual, special case: when we
use the user-copy routines not because it's a path that expects a user
pointer, but for a couple of ftrace/kgdb cases that want to do a kernel
copy, but do so using "unsafe" buffers, and use the user-copy routine to
gracefully handle faults.  IOW, for probe_kernel_write().

And that broke for the case of a faulting kernel destination, because we
saw the kernel destination and wanted to try to clear the tail of the
buffer.  Which doesn't work, since that's what faults.

This only triggers for things like kgdb and ftrace users (eg trying
setting a breakpoint on read-only memory), but it's definitely a bug.
The fix is to not compare against the kernel address start (TASK_SIZE),
but instead use the same limits "access_ok()" uses.
Reported-and-tested-by: NJan Beulich <jbeulich@suse.com>
Cc: stable@vger.kernel.org # 4.0
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Patch e68410eb ("crypto: x86/sha512_ssse3 - move SHA-384/512
SSSE3 implementation to base layer") changed the prototypes of the
core asm SHA-512 implementations so that they are compatible with
the prototype used by the base layer.

However, in one instance, the register that was used for passing the
input buffer was reused as a scratch register later on in the code,
and since the input buffer param changed places with the digest param
-which needs to be written back before the function returns- this
resulted in the scratch register to be dereferenced in a memory write
operation, causing a GPF.

Fix this by changing the scratch register to use the same register as
the input buffer param again.

Fixes: e68410eb ("crypto: x86/sha512_ssse3 - move SHA-384/512 SSSE3 implementation to base layer")
Reported-By: NBobby Powers <bobbypowers@gmail.com>
Tested-By: NBobby Powers <bobbypowers@gmail.com>
Signed-off-by: NArd Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>

- flush dcache before flush instruction cache
- remork update_mmu_cache and flush_dcache_page
- add shmparam.h
Signed-off-by: NLey Foon Tan <lftan@altera.com>

Reported by the header checker (CONFIG_HEADERS_CHECK=y):

  CHECK   usr/include/asm/ (31 files)
./usr/include/asm/ptrace.h:77: found __[us]{8,16,32,64} type without #include <linux/types.h>
Signed-off-by: NEzequiel Garcia <ezequiel@vanguardiasur.com.ar>
Acked-by: NLey Foon Tan <lftan@altera.com>

Signed-off-by: NSteven Miao <realmz6@gmail.com>

The related syscalls are below which may cause samples/kdbus building
break in next-20150401 tree, the related information and error:

    CALL    scripts/checksyscalls.sh
  <stdin>:1223:2: warning: #warning syscall kcmp not implemented [-Wcpp]
  <stdin>:1226:2: warning: #warning syscall finit_module not implemented [-Wcpp]
  <stdin>:1229:2: warning: #warning syscall sched_setattr not implemented [-Wcpp]
  <stdin>:1232:2: warning: #warning syscall sched_getattr not implemented [-Wcpp]
  <stdin>:1235:2: warning: #warning syscall renameat2 not implemented [-Wcpp]
  <stdin>:1238:2: warning: #warning syscall seccomp not implemented [-Wcpp]
  <stdin>:1241:2: warning: #warning syscall getrandom not implemented [-Wcpp]
  <stdin>:1244:2: warning: #warning syscall memfd_create not implemented [-Wcpp]
  <stdin>:1247:2: warning: #warning syscall bpf not implemented [-Wcpp]
  <stdin>:1250:2: warning: #warning syscall execveat not implemented [-Wcpp]
  [...]
    HOSTCC  samples/kdbus/kdbus-workers
  samples/kdbus/kdbus-workers.c: In function ‘prime_new’:
  samples/kdbus/kdbus-workers.c:930:18: error: ‘__NR_memfd_create’ undeclared (first use in this function)
    p->fd = syscall(__NR_memfd_create, "prime-area", MFD_CLOEXEC);
                    ^
  samples/kdbus/kdbus-workers.c:930:18: note: each undeclared identifier is reported only once for each function it appears in
Signed-off-by: NChen Gang <gang.chen.5i5j@gmail.com>

Remove the function kgdb_post_primary_code() 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>
Acked-by: NSonic Zhang <sonic.zhang@analog.com>

Rework of the prandom device with introduction of a new SHA-512 based
NIST SP 800-90 conform deterministic random bit generator.
Signed-off-by: NHarald Freudenberger <freude@linux.vnet.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

After the file ptes have been removed the bit combination used to
encode non-linear mappings can be reused for the swap ptes. This
frees up a precious pte software bit. Reflect the change in the
swap encoding in the comments and do some cleanup while we are
at it.
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

The dirty & young bit from the pmd is not copied correctly to the
pseudo pte in __pmd_to_pte. In fact it is not copied at all, the
bits get lost. As the old style huge page currently does not need
the dirty & young information this has no effect, but may be needed
in the future.
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

The new ebpf code uses e.g. the laal instruction which is part of the
interlocked-access facility 1 which again was introduced with z196.

So we must make sure the ebpf code generator depends on MARCH_Z196_FEATURES.
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>

Replacing a 2K page table with a 4K page table while a VMA is active
for the affected memory region is fundamentally broken. Rip out the
page table reallocation code and replace it with a simple system
control 'vm.allocate_pgste'. If the system control is set the page
tables for all processes are allocated as full 4K pages, even for
processes that do not need it.
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Introduce KEXEC_CONTROL_MEMORY_GFP to allow the architecture code
to override the gfp flags of the allocation for the kexec control
page. The loop in kimage_alloc_normal_control_pages allocates pages
with GFP_KERNEL until a page is found that happens to have an
address smaller than the KEXEC_CONTROL_MEMORY_LIMIT. On systems
with a large memory size but a small KEXEC_CONTROL_MEMORY_LIMIT
the loop will keep allocating memory until the oom killer steps in.
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>