Reported by Mikulas Patocka, kmemcheck currently barks out a
false positive since we don't have special kmemcheck annotation
for bitfields used in bpf_prog structure.
We currently have jited:1, len:31 and thus when accessing len
while CONFIG_KMEMCHECK enabled, kmemcheck throws a warning that
we're reading uninitialized memory.
As we don't need the whole bit universe for pages member, we
can just split it to u16 and use a bool flag for jited instead
of a bitfield.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Acked-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Introduced in commit 314beb9bca ("x86: bpf_jit_comp: secure bpf jit
against spraying attacks") and later on replicated in aa2d2c73c2
("s390/bpf,jit: address randomize and write protect jit code") for
s390 architecture, write protection for BPF JIT images got added and
a random start address of the JIT code, so that it's not on a page
boundary anymore.
Since both use a very similar allocator for the BPF binary header,
we can consolidate this code into the BPF core as it's mostly JIT
independant anyway.
This will also allow for future archs that support DEBUG_SET_MODULE_RONX
to just reuse instead of reimplementing it.
JIT tested on x86_64 and s390x with BPF test suite.
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Acked-by: Alexei Starovoitov <ast@plumgrid.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
add BPF_LD_IMM64 instruction to load 64-bit immediate value into a register.
All previous instructions were 8-byte. This is first 16-byte instruction.
Two consecutive 'struct bpf_insn' blocks are interpreted as single instruction:
insn[0].code = BPF_LD | BPF_DW | BPF_IMM
insn[0].dst_reg = destination register
insn[0].imm = lower 32-bit
insn[1].code = 0
insn[1].imm = upper 32-bit
All unused fields must be zero.
Classic BPF has similar instruction: BPF_LD | BPF_W | BPF_IMM
which loads 32-bit immediate value into a register.
x64 JITs it as single 'movabsq %rax, imm64'
arm64 may JIT as sequence of four 'movk x0, #imm16, lsl #shift' insn
Note that old eBPF programs are binary compatible with new interpreter.
It helps eBPF programs load 64-bit constant into a register with one
instruction instead of using two registers and 4 instructions:
BPF_MOV32_IMM(R1, imm32)
BPF_ALU64_IMM(BPF_LSH, R1, 32)
BPF_MOV32_IMM(R2, imm32)
BPF_ALU64_REG(BPF_OR, R1, R2)
User space generated programs will use this instruction to load constants only.
To tell kernel that user space needs a pointer the _pseudo_ variant of
this instruction may be added later, which will use extra bits of encoding
to indicate what type of pointer user space is asking kernel to provide.
For example 'off' or 'src_reg' fields can be used for such purpose.
src_reg = 1 could mean that user space is asking kernel to validate and
load in-kernel map pointer.
src_reg = 2 could mean that user space needs readonly data section pointer
src_reg = 3 could mean that user space needs a pointer to per-cpu local data
All such future pseudo instructions will not be carrying the actual pointer
as part of the instruction, but rather will be treated as a request to kernel
to provide one. The kernel will verify the request_for_a_pointer, then
will drop _pseudo_ marking and will store actual internal pointer inside
the instruction, so the end result is the interpreter and JITs never
see pseudo BPF_LD_IMM64 insns and only operate on generic BPF_LD_IMM64 that
loads 64-bit immediate into a register. User space never operates on direct
pointers and verifier can easily recognize request_for_pointer vs other
instructions.
Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Pull EFI fixes from Matt Fleming:
* Fix early boot regression affecting x86 EFI boot stub when loading
initrds above 4GB - Yinghai Lu
* Relocate GOT entries in the x86 EFI boot stub now that we have
symbols with global visibility - Matt Fleming
* fdt memory reservation fix for arm64 - Mark Salter
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The new split Intel uncore driver code that recently went
into tip added a section mismatch, which the build process
complains about.
uncore_pmu_register() can be called from uncore_pci_probe,()
which is not __init and can be called from pci driver ->probe.
I'm not fully sure if it's actually possible to call the probe
function later, but it seems safer to mark uncore_pmu_register
not __init.
This also fixes the warning.
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1409332858-29039-1-git-send-email-andi@firstfloor.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
A commit in linux-next was causing boot to fail and bisection
identified the patch 4ba2968420 ("percpu: Resolve ambiguities in
__get_cpu_var/cpumask_var_"). One of the changes in that patch looks
very suspicious. Reverting the full patch fixes boot as does this
fixlet.
Signed-off-by: Mel Gorman <mgorman@suse.de>
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Christoph Lameter <cl@linux.com>
On KVM on my box, this reduces the overhead from an always-accept
seccomp filter from ~130ns to ~17ns. Most of that comes from
avoiding IRET on every syscall when seccomp is enabled.
In extremely approximate hacked-up benchmarking, just bypassing IRET
saves about 80ns, so there's another 43ns of savings here from
simplifying the seccomp path.
The diffstat is also rather nice :)
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Link: http://lkml.kernel.org/r/a3dbd267ee990110478d349f78cccfdac5497a84.1409954077.git.luto@amacapital.net
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
For slowpath syscalls, we initialize regs->ax to -ENOSYS and stick
the syscall number into regs->orig_ax prior to any possible tracing
and syscall execution. This is user-visible ABI used by ptrace
syscall emulation and seccomp.
For fastpath syscalls, there's no good reason not to do the same
thing. It's even slightly simpler than what we're currently doing.
It probably has no measureable performance impact. It should have
no user-visible effect.
The purpose of this patch is to prepare for two-phase syscall
tracing, in which the first phase might modify the saved RAX without
leaving the fast path. This change is just subtle enough that I'm
keeping it separate.
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Link: http://lkml.kernel.org/r/01218b493f12ae2f98034b78c9ae085e38e94350.1409954077.git.luto@amacapital.net
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
This splits syscall_trace_enter into syscall_trace_enter_phase1 and
syscall_trace_enter_phase2. Only phase 2 has full pt_regs, and only
phase 2 is permitted to modify any of pt_regs except for orig_ax.
The intent is that phase 1 can be called from the syscall fast path.
In this implementation, phase1 can handle any combination of
TIF_NOHZ (RCU context tracking), TIF_SECCOMP, and TIF_SYSCALL_AUDIT,
unless seccomp requests a ptrace event, in which case phase2 is
forced.
In principle, this could yield a big speedup for TIF_NOHZ as well as
for TIF_SECCOMP if syscall exit work were similarly split up.
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Link: http://lkml.kernel.org/r/2df320a600020fda055fccf2b668145729dd0c04.1409954077.git.luto@amacapital.net
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
The RCU context tracking code requires that arch code call
user_exit() on any entry into kernel code if TIF_NOHZ is set. This
patch adds a check for TIF_NOHZ and a comment to the syscall entry
tracing code.
The main purpose of this patch is to make the code easier to follow:
one can read the body of user_exit and of every function it calls
without finding any explanation of why it's called for traced
syscalls but not for untraced syscalls. This makes it clear when
user_exit() is necessary.
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Link: http://lkml.kernel.org/r/0b13e0e24ec0307d67ab7a23b58764f6b1270116.1409954077.git.luto@amacapital.net
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Maarten reported that his Macbook pro 8.2 stopped booting after commit
f23cf8bd5c ("efi/x86: efistub: Move shared dependencies to
<asm/efi.h>"), the main feature of which is changing the visibility of
symbol 'efi_early' from local to global.
By making 'efi_early' global we end up requiring an entry in the Global
Offset Table. Unfortunately, while we do include code to fixup GOT
entries in the early boot code, it's only called after we've executed
the EFI boot stub.
What this amounts to is that references to 'efi_early' in the EFI boot
stub don't point to the correct place.
Since we've got multiple boot entry points we need to be prepared to
fixup the GOT in multiple places, while ensuring that we never do it
more than once, otherwise the GOT entries will still point to the wrong
place.
Reported-by: Maarten Lankhorst <maarten.lankhorst@canonical.com>
Tested-by: Maarten Lankhorst <maarten.lankhorst@canonical.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
Mantas found that after commit 4bf7111f50 ("x86/efi: Support initrd
loaded above 4G"), the kernel freezes at the earliest possible moment
when trying to boot via UEFI on Asus laptop.
Revert to old way to load initrd under 4G on first try, second try will
use above 4G buffer when initrd is too big and does not fit under 4G.
[ The cause of the freeze appears to be a firmware bug when reading
file data into buffers above 4GB, though the exact reason is unknown.
Mantas reports that the hang can be avoid if the file size is a
multiple of 512 bytes, but I've seen some ASUS firmware simply
corrupting the file data rather than freezing.
Laszlo fixed an issue in the upstream EDK2 DiskIO code in Aug 2013
which may possibly be related, commit 4e39b75e ("MdeModulePkg/DiskIoDxe:
fix source/destination pointer of overrun transfer").
Whatever the cause, it's unlikely that a fix will be forthcoming
from the vendor, hence the workaround - Matt ]
Cc: Laszlo Ersek <lersek@redhat.com>
Reported-by: Mantas Mikulėnas <grawity@gmail.com>
Reported-by: Harald Hoyer <harald@redhat.com>
Tested-by: Anders Darander <anders@chargestorm.se>
Tested-by: Calvin Walton <calvin.walton@kepstin.ca>
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
Percpu allocator now supports allocation mask. Add @gfp to
percpu_counter_init() so that !GFP_KERNEL allocation masks can be used
with percpu_counters too.
We could have left percpu_counter_init() alone and added
percpu_counter_init_gfp(); however, the number of users isn't that
high and introducing _gfp variants to all percpu data structures would
be quite ugly, so let's just do the conversion. This is the one with
the most users. Other percpu data structures are a lot easier to
convert.
This patch doesn't make any functional difference.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Jan Kara <jack@suse.cz>
Acked-by: "David S. Miller" <davem@davemloft.net>
Cc: x86@kernel.org
Cc: Jens Axboe <axboe@kernel.dk>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
With eBPF getting more extended and exposure to user space is on it's way,
hardening the memory range the interpreter uses to steer its command flow
seems appropriate. This patch moves the to be interpreted bytecode to
read-only pages.
In case we execute a corrupted BPF interpreter image for some reason e.g.
caused by an attacker which got past a verifier stage, it would not only
provide arbitrary read/write memory access but arbitrary function calls
as well. After setting up the BPF interpreter image, its contents do not
change until destruction time, thus we can setup the image on immutable
made pages in order to mitigate modifications to that code. The idea
is derived from commit 314beb9bca ("x86: bpf_jit_comp: secure bpf jit
against spraying attacks").
This is possible because bpf_prog is not part of sk_filter anymore.
After setup bpf_prog cannot be altered during its life-time. This prevents
any modifications to the entire bpf_prog structure (incl. function/JIT
image pointer).
Every eBPF program (including classic BPF that are migrated) have to call
bpf_prog_select_runtime() to select either interpreter or a JIT image
as a last setup step, and they all are being freed via bpf_prog_free(),
including non-JIT. Therefore, we can easily integrate this into the
eBPF life-time, plus since we directly allocate a bpf_prog, we have no
performance penalty.
Tested with seccomp and test_bpf testsuite in JIT/non-JIT mode and manual
inspection of kernel_page_tables. Brad Spengler proposed the same idea
via Twitter during development of this patch.
Joint work with Hannes Frederic Sowa.
Suggested-by: Brad Spengler <spender@grsecurity.net>
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Cc: Alexei Starovoitov <ast@plumgrid.com>
Cc: Kees Cook <keescook@chromium.org>
Acked-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Currently, if a permission error happens during the translation of
the final GPA to HPA, walk_addr_generic returns 0 but does not fill
in walker->fault. To avoid this, add an x86_exception* argument
to the translate_gpa function, and let it fill in walker->fault.
The nested_page_fault field will be true, since the walk_mmu is the
nested_mmu and translate_gpu instead operates on the "outer" (NPT)
instance.
Reported-by: Valentine Sinitsyn <valentine.sinitsyn@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
If a nested page fault happens during emulation, we will inject a vmexit,
not a page fault. However because writeback happens after the injection,
we will write ctxt->eip from L2 into the L1 EIP. We do not write back
if an instruction caused an interception vmexit---do the same for page
faults.
Suggested-by: Gleb Natapov <gleb@kernel.org>
Reviewed-by: Gleb Natapov <gleb@kernel.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The secure_computing function took a syscall number parameter, but
it only paid any attention to that parameter if seccomp mode 1 was
enabled. Rather than coming up with a kludge to get the parameter
to work in mode 2, just remove the parameter.
To avoid churn in arches that don't have seccomp filters (and may
not even support syscall_get_nr right now), this leaves the
parameter in secure_computing_strict, which is now a real function.
For ARM, this is a bit ugly due to the fact that ARM conditionally
supports seccomp filters. Fixing that would probably only be a
couple of lines of code, but it should be coordinated with the audit
maintainers.
This will be a slight slowdown on some arches. The right fix is to
pass in all of seccomp_data instead of trying to make just the
syscall nr part be fast.
This is a prerequisite for making two-phase seccomp work cleanly.
Cc: Russell King <linux@arm.linux.org.uk>
Cc: linux-arm-kernel@lists.infradead.org
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: linux-s390@vger.kernel.org
Cc: x86@kernel.org
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Kees Cook <keescook@chromium.org>
This is similar to what the EPT code does with the exit qualification.
This allows the guest to see a valid value for bits 33:32.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Bit 8 would be the "global" bit, which does not quite make sense for non-leaf
page table entries. Intel ignores it; AMD ignores it in PDEs, but reserves it
in PDPEs and PML4Es. The SVM test is relying on this behavior, so enforce it.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The following events can lead to an incorrect KVM_EXIT_MMIO bubbling
up to userspace:
(1) Guest accesses gpa X without a memory slot. The gfn is cached in
struct kvm_vcpu_arch (mmio_gfn). On Intel EPT-enabled hosts, KVM sets
the SPTE write-execute-noread so that future accesses cause
EPT_MISCONFIGs.
(2) Host userspace creates a memory slot via KVM_SET_USER_MEMORY_REGION
covering the page just accessed.
(3) Guest attempts to read or write to gpa X again. On Intel, this
generates an EPT_MISCONFIG. The memory slot generation number that
was incremented in (2) would normally take care of this but we fast
path mmio faults through quickly_check_mmio_pf(), which only checks
the per-vcpu mmio cache. Since we hit the cache, KVM passes a
KVM_EXIT_MMIO up to userspace.
This patch fixes the issue by using the memslot generation number
to validate the mmio cache.
Cc: stable@vger.kernel.org
Signed-off-by: David Matlack <dmatlack@google.com>
[xiaoguangrong: adjust the code to make it simpler for stable-tree fix.]
Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Reviewed-by: David Matlack <dmatlack@google.com>
Reviewed-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Tested-by: David Matlack <dmatlack@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
vcpu exits and memslot mutations can run concurrently as long as the
vcpu does not aquire the slots mutex. Thus it is theoretically possible
for memslots to change underneath a vcpu that is handling an exit.
If we increment the memslot generation number again after
synchronize_srcu_expedited(), vcpus can safely cache memslot generation
without maintaining a single rcu_dereference through an entire vm exit.
And much of the x86/kvm code does not maintain a single rcu_dereference
of the current memslots during each exit.
We can prevent the following case:
vcpu (CPU 0) | thread (CPU 1)
--------------------------------------------+--------------------------
1 vm exit |
2 srcu_read_unlock(&kvm->srcu) |
3 decide to cache something based on |
old memslots |
4 | change memslots
| (increments generation)
5 | synchronize_srcu(&kvm->srcu);
6 retrieve generation # from new memslots |
7 tag cache with new memslot generation |
8 srcu_read_unlock(&kvm->srcu) |
... |
<action based on cache occurs even |
though the caching decision was based |
on the old memslots> |
... |
<action *continues* to occur until next |
memslot generation change, which may |
be never> |
|
By incrementing the generation after synchronizing with kvm->srcu readers,
we ensure that the generation retrieved in (6) will become invalid soon
after (8).
Keeping the existing increment is not strictly necessary, but we
do keep it and just move it for consistency from update_memslots to
install_new_memslots. It invalidates old cached MMIOs immediately,
instead of having to wait for the end of synchronize_srcu_expedited,
which makes the code more clearly correct in case CPU 1 is preempted
right after synchronize_srcu() returns.
To avoid halving the generation space in SPTEs, always presume that the
low bit of the generation is zero when reconstructing a generation number
out of an SPTE. This effectively disables MMIO caching in SPTEs during
the call to synchronize_srcu_expedited. Using the low bit this way is
somewhat like a seqcount---where the protected thing is a cache, and
instead of retrying we can simply punt if we observe the low bit to be 1.
Cc: stable@vger.kernel.org
Signed-off-by: David Matlack <dmatlack@google.com>
Reviewed-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Reviewed-by: David Matlack <dmatlack@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The next patch will give a meaning (a la seqcount) to the low bit of the
generation number. Ensure that it matches between kvm->memslots->generation
and kvm_current_mmio_generation().
Cc: stable@vger.kernel.org
Reviewed-by: David Matlack <dmatlack@google.com>
Reviewed-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Cosmetic, but imho memset(&dst->thread.fpu, 0) is not good simply
because it hides the (important) usage of ->has_fpu/etc from grep.
Change this code to initialize the members explicitly.
And note that ->last_cpu = 0 looks simply wrong, this can confuse
fpu_lazy_restore() if per_cpu(fpu_owner_task, 0) has already exited
and copy_process() re-allocated the same task_struct. Fortunately
this is not actually possible because child->fpu_counter == 0 and
thus fpu_lazy_restore() will not be called, but still this is not
clean/robust.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Link: http://lkml.kernel.org/r/20140902175727.GA21666@redhat.com
Reviewed-by: Suresh Siddha <sbsiddha@gmail.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
arch_dup_task_struct() copies thread.fpu if fpu_allocated(), this
looks suboptimal and misleading. Say, a forking process could use
FPU only once in a signal handler but now tsk_used_math(src) == F,
in this case the child gets a copy of fpu->state for no reason. The
child won't use the saved registers anyway even if it starts to use
FPU, this can only avoid fpu_alloc() in do_device_not_available().
Change this code to check tsk_used_math(current) instead. We still
need to clear fpu->has_fpu/state, we could do this memset(0) under
fpu_allocated() check but I think this doesn't make sense. See also
the next change.
use_eager_fpu() assumes that fpu_allocated() is always true, but a
forking task (and thus its child) must always have PF_USED_MATH set,
otherwise the child can either use FPU without used_math() (note that
switch_fpu_prepare() doesn't do stts() in this case), or it will be
killed by do_device_not_available()->BUG_ON(use_eager_fpu).
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Link: http://lkml.kernel.org/r/20140902175723.GA21659@redhat.com
Reviewed-by: Suresh Siddha <sbsiddha@gmail.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Set the IRQCHIP_SKIP_SET_WAKE for IOAPIC IRQ chip objects so that
interrupts from them can work as wakeup interrupts for suspend-to-idle.
After this change, running enable_irq_wake() on one of the IRQs in
question will succeed and IRQD_WAKEUP_STATE will be set for it, so
all of the suspend-to-idle wakeup mechanics introduced previously
will work for it automatically.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
The last user of set_pmd_pfn() went away in commit f03574f2d5, so this
has been dead code for over a year.
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
arch/x86/include/asm/pgtable_32.h | 3 ---
arch/x86/mm/pgtable_32.c | 35 -----------------------------------
2 files changed, 38 deletions(-)
Pull x86 fixes from Peter Anvin:
"One patch to avoid assigning interrupts we don't actually have on
non-PC platforms, and two patches that addresses bugs in the new
IOAPIC assignment code"
* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86, irq, PCI: Keep IRQ assignment for runtime power management
x86: irq: Fix bug in setting IOAPIC pin attributes
x86: Fix non-PC platform kernel crash on boot due to NULL dereference
Thomas reported that build of x86_64 kernel was failing for him. He is
using 32bit tool chain.
Problem is that while compiling purgatory, I have not specified -m64
flag. And 32bit tool chain must be assuming -m32 by default.
Following is error message.
(mini) [~/work/linux-2.6] make
scripts/kconfig/conf --silentoldconfig Kconfig
CHK include/config/kernel.release
UPD include/config/kernel.release
CHK include/generated/uapi/linux/version.h
CHK include/generated/utsrelease.h
UPD include/generated/utsrelease.h
CC arch/x86/purgatory/purgatory.o
arch/x86/purgatory/purgatory.c:1:0: error: code model 'large' not supported in
the 32 bit mode
Fix it by explicitly passing appropriate -m64/-m32 build flag for
purgatory.
Reported-by: Thomas Glanzmann <thomas@glanzmann.de>
Tested-by: Thomas Glanzmann <thomas@glanzmann.de>
Suggested-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently new system call kexec_file_load() and all the associated code
compiles if CONFIG_KEXEC=y. But new syscall also compiles purgatory
code which currently uses gcc option -mcmodel=large. This option seems
to be available only gcc 4.4 onwards.
Hiding new functionality behind a new config option will not break
existing users of old gcc. Those who wish to enable new functionality
will require new gcc. Having said that, I am trying to figure out how
can I move away from using -mcmodel=large but that can take a while.
I think there are other advantages of introducing this new config
option. As this option will be enabled only on x86_64, other arches
don't have to compile generic kexec code which will never be used. This
new code selects CRYPTO=y and CRYPTO_SHA256=y. And all other arches had
to do this for CONFIG_KEXEC. Now with introduction of new config
option, we can remove crypto dependency from other arches.
Now CONFIG_KEXEC_FILE is available only on x86_64. So whereever I had
CONFIG_X86_64 defined, I got rid of that.
For CONFIG_KEXEC_FILE, instead of doing select CRYPTO=y, I changed it to
"depends on CRYPTO=y". This should be safer as "select" is not
recursive.
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Tested-by: Shaun Ruffell <sruffell@digium.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Sasha Levin has shown oopses on ffffea0003480048 and ffffea0003480008 at
mm/memory.c:1132, running Trinity on different 3.16-rc-next kernels:
where zap_pte_range() checks page->mapping to see if PageAnon(page).
Those addresses fit struct pages for pfns d2001 and d2000, and in each
dump a register or a stack slot showed d2001730 or d2000730: pte flags
0x730 are PCD ACCESSED PROTNONE SPECIAL IOMAP; and Sasha's e820 map has
a hole between cfffffff and 100000000, which would need special access.
Commit c46a7c817e ("x86: define _PAGE_NUMA by reusing software bits on
the PMD and PTE levels") has broken vm_normal_page(): a PROTNONE SPECIAL
pte no longer passes the pte_special() test, so zap_pte_range() goes on
to try to access a non-existent struct page.
Fix this by refining pte_special() (SPECIAL with PRESENT or PROTNONE) to
complement pte_numa() (SPECIAL with neither PRESENT nor PROTNONE). A
hint that this was a problem was that c46a7c817e added pte_numa() test
to vm_normal_page(), and moved its is_zero_pfn() test from slow to fast
path: This was papering over a pte_special() snag when the zero page was
encountered during zap. This patch reverts vm_normal_page() to how it
was before, relying on pte_special().
It still appears that this patch may be incomplete: aren't there other
places which need to be handling PROTNONE along with PRESENT? For
example, pte_mknuma() clears _PAGE_PRESENT and sets _PAGE_NUMA, but on a
PROT_NONE area, that would make it pte_special(). This is side-stepped
by the fact that NUMA hinting faults skipped PROT_NONE VMAs and there
are no grounds where a NUMA hinting fault on a PROT_NONE VMA would be
interesting.
Fixes: c46a7c817e ("x86: define _PAGE_NUMA by reusing software bits on the PMD and PTE levels")
Reported-by: Sasha Levin <sasha.levin@oracle.com>
Tested-by: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Mel Gorman <mgorman@suse.de>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Cyrill Gorcunov <gorcunov@gmail.com>
Cc: Matthew Wilcox <matthew.r.wilcox@intel.com>
Cc: <stable@vger.kernel.org> [3.16]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The check introduced in commit d7a2a246a1 (KVM: x86: #GP when attempts to write reserved bits of Variable Range MTRRs, 2014-08-19)
will break if the guest maxphyaddr is higher than the host's (which
sometimes happens depending on your hardware and how QEMU is
configured).
To fix this, use cpuid_maxphyaddr similar to how the APIC_BASE MSR
does already.
Reported-by: Jan Kiszka <jan.kiszka@siemens.com>
Tested-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
In the beggining was on_each_cpu(), which required an unused argument to
kvm_arch_ops.hardware_{en,dis}able, but this was soon forgotten.
Remove unnecessary arguments that stem from this.
Signed-off-by: Radim KrÄmář <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
