Some processes (CRIU) are moving the vDSO area using the mremap system
call. As a consequence the kernel reference to the vDSO base address is
no more valid and the signal return frame built once the vDSO has been
moved is not pointing to the new sigreturn address.
This patch handles vDSO remapping and unmapping.
Signed-off-by: Laurent Dufour <ldufour@linux.vnet.ibm.com>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Pavel Emelyanov <xemul@parallels.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We are adding support for DMA memory pre-registration to be used in
conjunction with VFIO. The idea is that the userspace which is going to
run a guest may want to pre-register a user space memory region so
it all gets pinned once and never goes away. Having this done,
a hypervisor will not have to pin/unpin pages on every DMA map/unmap
request. This is going to help with multiple pinning of the same memory.
Another use of it is in-kernel real mode (mmu off) acceleration of
DMA requests where real time translation of guest physical to host
physical addresses is non-trivial and may fail as linux ptes may be
temporarily invalid. Also, having cached host physical addresses
(compared to just pinning at the start and then walking the page table
again on every H_PUT_TCE), we can be sure that the addresses which we put
into TCE table are the ones we already pinned.
This adds a list of memory regions to mm_context_t. Each region consists
of a header and a list of physical addresses. This adds API to:
1. register/unregister memory regions;
2. do final cleanup (which puts all pre-registered pages);
3. do userspace to physical address translation;
4. manage usage counters; multiple registration of the same memory
is allowed (once per container).
This implements 2 counters per registered memory region:
- @mapped: incremented on every DMA mapping; decremented on unmapping;
initialized to 1 when a region is just registered; once it becomes zero,
no more mappings allowe;
- @used: incremented on every "register" ioctl; decremented on
"unregister"; unregistration is allowed for DMA mapped regions unless
it is the very last reference. For the very last reference this checks
that the region is still mapped and returns -EBUSY so the userspace
gets to know that memory is still pinned and unregistration needs to
be retried; @used remains 1.
Host physical addresses are stored in vmalloc'ed array. In order to
access these in the real mode (mmu off), there is a real_vmalloc_addr()
helper. In-kernel acceleration patchset will move it from KVM to MMU code.
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
We now only support cpus that use an SLB, so we don't need an MMU
feature to indicate that.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Old cpus didn't have a Segment Lookaside Buffer (SLB), instead they had
a Segment Table (STAB). Now that we've dropped support for those cpus,
we can remove the STAB support entirely.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Most of the stuff from kernel/sched.c was moved to kernel/sched/core.c long time
back and the comments/Documentation never got updated.
I figured it out when I was going through sched-domains.txt and so thought of
fixing it globally.
I haven't crossed check if the stuff that is referenced in sched/core.c by all
these files is still present and hasn't changed as that wasn't the motive behind
this patch.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/cdff76a265326ab8d71922a1db5be599f20aad45.1370329560.git.viresh.kumar@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Icswx is a PowerPC instruction to send data to a co-processor. On Book-S
processors the LPAR_ID and process ID (PID) of the owning process are
registered in the window context of the co-processor at initialization
time. When the icswx instruction is executed the L2 generates a cop-reg
transaction on PowerBus. The transaction has no address and the
processor does not perform an MMU access to authenticate the transaction.
The co-processor compares the LPAR_ID and the PID included in the
transaction and the LPAR_ID and PID held in the window context to
determine if the process is authorized to generate the transaction.
The OS needs to assign a 16-bit PID for the process. This cop-PID needs
to be updated during context switch. The cop-PID needs to be destroyed
when the context is destroyed.
Signed-off-by: Sonny Rao <sonnyrao@linux.vnet.ibm.com>
Signed-off-by: Tseng-Hui (Frank) Lin <thlin@linux.vnet.ibm.com>
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Some of the 64bit PPC CPU features are MMU-related, so this patch moves
them to MMU_FTR_ bits. All cpu_has_feature()-style tests are moved to
mmu_has_feature(), and seven feature bits are freed as a result.
Signed-off-by: Matt Evans <matt@ozlabs.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
We need to reserve a context from KVM to make sure we have our own
segment space. While we did that split for Book3S_64 already, 32 bit
is still outstanding.
So let's split it now.
Signed-off-by: Alexander Graf <agraf@suse.de>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
CC: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Avi Kivity <avi@redhat.com>
For KVM we need to allocate a new context id, but don't really care about
all the mm context around it.
So let's split the alloc and destroy functions for the context id, so we can
grab one without allocating an mm context.
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
This adds the TLB miss handler assembly, the low level TLB flush routines
along with the necessary hook for dealing with our virtual page tables
or indirect TLB entries that need to be flushes when PTE pages are freed.
There is currently no support for hugetlbfs
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Our 64-bit hash context handling has no init function, but 64-bit Book3E
will use the common mmu_context_nohash.c code which does, so define an
empty inline mmu_context_init() for 64-bit server and call it from
our 64-bit setup_arch()
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Acked-by: Kumar Gala <galak@kernel.crashing.org>
Makes code futureproof against the impending change to mm->cpu_vm_mask.
It's also a chance to use the new cpumask_ ops which take a pointer
(the older ones are deprecated, but there's no hurry for arch code).
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
This splits the mmu_context handling between 32-bit hash based
processors, 64-bit hash based processors and everybody else. This is
preliminary work for adding SMP support for BookE processors.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Acked-by: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
The 32-bit hash code didn't need it so far so we don't update
mm->cpu_vm_mask on context switch. This however will break when we
merge the RCU based page table freeing patch and other upcoming 32-bit
embedded SMP work, so this adds the update.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
When we fork, init_new_context() improperly resets the vdso_base
of the new context to 0. That means that the new process loses
access to the vdso for signal trampolines.
The initialization should be unnecessary anyway as the context
on a fresh mm should be 0 in the first place and binfmt_elf
will initialize that value for a newly loaded process.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
from include/asm-powerpc. This is the result of a
mkdir arch/powerpc/include/asm
git mv include/asm-powerpc/* arch/powerpc/include/asm
Followed by a few documentation/comment fixups and a couple of places
where <asm-powepc/...> was being used explicitly. Of the latter only
one was outside the arch code and it is a driver only built for powerpc.
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Laurent Dufour