During early boot, load_ucode_intel_ap() uses __load_ucode_intel()
to obtain a pointer to the relevant microcode patch (embedded in the
initrd), and stores this value in 'intel_ucode_patch' to speed up the
microcode patch application for subsequent CPUs.

On resuming from suspend-to-RAM, however, load_ucode_ap() calls
load_ucode_intel_ap() for each non-boot-CPU. By then the initramfs is
long gone so the pointer stored in 'intel_ucode_patch' no longer points to
a valid microcode patch.

Clear that pointer so that we effectively fall back to the CPU hotplug
notifier callbacks to update the microcode.
Signed-off-by: NDominik Brodowski <linux@dominikbrodowski.net>
[ Edit and massage commit message. ]
Signed-off-by: NBorislav Petkov <bp@suse.de>
Cc: <stable@vger.kernel.org> # 4.10..
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20170607095819.9754-1-bp@alien8.deSigned-off-by: NIngo Molnar <mingo@kernel.org>

native_safe_halt enables interrupts, and you just shouldn't
call rcu_irq_enter() with interrupts enabled.  Reorder the
call with the following local_irq_disable() to respect the
invariant.
Reported-by: NRoss Zwisler <ross.zwisler@linux.intel.com>
Cc: stable@vger.kernel.org
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Acked-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Tested-by: NWanpeng Li <wanpeng.li@hotmail.com>
Signed-off-by: NRadim Krčmář <rkrcmar@redhat.com>

A SoC variant of Geode GX1, notably NSC branded SC1100, seems to
report an inverted Device ID in its DIR0 configuration register,
specifically 0xb instead of the expected 0x4.

Catch this presumably quirky version so it's properly recognized
as GX1 and has its cache switched to write-back mode, which provides
a significant performance boost in most workloads.

SC1100's datasheet "Geode™ SC1100 Information Appliance On a Chip",
states in section 1.1.7.1 "Device ID" that device identification
values are specified in SC1100's device errata. These, however,
seem to not have been publicly released.

Wading through a number of boot logs and /proc/cpuinfo dumps found on
pastebin and blogs, this patch should mostly be relevant for a number
of now admittedly aging Soekris NET4801 and PC Engines WRAP devices,
the latter being the platform this issue was discovered on.
Performance impact was verified using "openssl speed", with
write-back caching scaling throughput between -3% and +41%.
Signed-off-by: NChristian Sünkenberg <christian.suenkenberg@student.kit.edu>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1496596719.26725.14.camel@student.kit.eduSigned-off-by: NIngo Molnar <mingo@kernel.org>

... to raw_smp_processor_id() to not trip the

  BUG: using smp_processor_id() in preemptible [00000000] code: swapper/0/1

check. The reasoning behind it is that __warn() already uses the raw_
variants but the show_regs() path on 32-bit doesn't.
Signed-off-by: NBorislav Petkov <bp@suse.de>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20170528092212.fiod7kygpjm23m3o@pd.tnicSigned-off-by: NIngo Molnar <mingo@kernel.org>

With CONFIG_DEBUG_PREEMPT enabled, I get:

  BUG: using smp_processor_id() in preemptible [00000000] code: swapper/0/1
  caller is debug_smp_processor_id
  CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.12.0-rc2+ #2
  Call Trace:
   dump_stack
   check_preemption_disabled
   debug_smp_processor_id
   save_microcode_in_initrd_amd
   ? microcode_init
   save_microcode_in_initrd
   ...

because, well, it says it above, we're using smp_processor_id() in
preemptible code.

But passing the CPU number is not really needed. It is only used to
determine whether we're on the BSP, and, if so, to save the microcode
patch for early loading.

 [ We don't absolutely need to do it on the BSP but we do that
   customarily there. ]

Instead, convert that function parameter to a boolean which denotes
whether the patch should be saved or not, thereby avoiding the use of
smp_processor_id() in preemptible code.
Signed-off-by: NBorislav Petkov <bp@suse.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20170528200414.31305-1-bp@alien8.deSigned-off-by: NIngo Molnar <mingo@kernel.org>

ftrace use module_alloc() to allocate trampoline pages. The mapping of
module_alloc() is RWX, which makes sense as the memory is written to right
after allocation. But nothing makes these pages RO after writing to them.

Add proper set_memory_rw/ro() calls to protect the trampolines after
modification.

Link: http://lkml.kernel.org/r/alpine.DEB.2.20.1705251056410.1862@nanosSigned-off-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NSteven Rostedt (VMware) <rostedt@goodmis.org>

Fix kprobes to set(recover) RWX bits correctly on trampoline
buffer before releasing it. Releasing readonly page to
module_memfree() crash the kernel.

Without this fix, if kprobes user register a bunch of kprobes
in function body (since kprobes on function entry usually
use ftrace) and unregister it, kernel hits a BUG and crash.

Link: http://lkml.kernel.org/r/149570868652.3518.14120169373590420503.stgit@devboxSigned-off-by: NMasami Hiramatsu <mhiramat@kernel.org>
Fixes: d0381c81 ("kprobes/x86: Set kprobes pages read-only")
Signed-off-by: NSteven Rostedt (VMware) <rostedt@goodmis.org>

This ensures that adjustments to x86_platform done by the hypervisor
setup is already respected by this simple calibration.

The current user of this, introduced by 1b5aeebf ("x86/earlyprintk:
Add support for earlyprintk via USB3 debug port"), comes much later
into play.

Fixes: dd759d93 ("x86/timers: Add simple udelay calibration")
Signed-off-by: NJan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Acked-by: NLu Baolu <baolu.lu@linux.intel.com>
Link: http://lkml.kernel.org/r/5e89fe60-aab3-2c1c-aba8-32f8ad376189@siemens.com

In the current form of the code, if a->replacementlen is 0, the reference
to *insnbuf for comparison touches potentially garbage memory. While it
doesn't affect the execution flow due to the subsequent a->replacementlen
comparison, it is (rightly) detected as use of uninitialized memory by a
runtime instrumentation currently under my development, and could be
detected as such by other tools in the future, too (e.g. KMSAN).

Fix the "false-positive" by reordering the conditions to first check the
replacement instruction length before referencing specific opcode bytes.
Signed-off-by: NMateusz Jurczyk <mjurczyk@google.com>
Reviewed-by: NBorislav Petkov <bp@suse.de>
Cc: Andy Lutomirski <luto@kernel.org>
Link: http://lkml.kernel.org/r/20170524135500.27223-1-mjurczyk@google.comSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

Dave Jones and Steven Rostedt reported unwinder warnings like the
following:

  WARNING: kernel stack frame pointer at ffff8800bda0ff30 in sshd:1090 has bad value 000055b32abf1fa8

In both cases, the unwinder was attempting to unwind from an ftrace
handler into entry code.  The callchain was something like:

  syscall entry code
    C function
      ftrace handler
        save_stack_trace()

The problem is that the unwinder's end-of-stack logic gets confused by
the way ftrace lays out the stack frame (with fentry enabled).

I was able to recreate this warning with:

  echo call_usermodehelper_exec_async:stacktrace > /sys/kernel/debug/tracing/set_ftrace_filter
  (exit login session)

I considered fixing this by changing the ftrace code to rewrite the
stack to make the unwinder happy.  But that seemed too intrusive after I
implemented it.  Instead, just add another check to the unwinder's
end-of-stack logic to detect this special case.

Side note: We could probably get rid of these end-of-stack checks by
encoding the frame pointer for syscall entry just like we do for
interrupt entry.  That would be simpler, but it would also be a lot more
intrusive since it would slightly affect the performance of every
syscall.
Reported-by: NDave Jones <davej@codemonkey.org.uk>
Reported-by: NSteven Rostedt <rostedt@goodmis.org>
Signed-off-by: NJosh Poimboeuf <jpoimboe@redhat.com>
Acked-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: live-patching@vger.kernel.org
Fixes: c32c47c6 ("x86/unwind: Warn on bad frame pointer")
Link: http://lkml.kernel.org/r/671ba22fbc0156b8f7e0cfa5ab2a795e08bc37e1.1495553739.git.jpoimboe@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

Export the function which checks whether an MCE is a memory error to
other users so that we can reuse the logic. Drop the boot_cpu_data use,
while at it, as mce.cpuvendor already has the CPU vendor in there.

Integrate a piece from a patch from Vishal Verma
<vishal.l.verma@intel.com> to export it for modules (nfit).

The main reason we're exporting it is that the nfit handler
nfit_handle_mce() needs to detect a memory error properly before doing
its recovery actions.
Signed-off-by: NBorislav Petkov <bp@suse.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: <stable@vger.kernel.org>
Link: http://lkml.kernel.org/r/20170519093915.15413-2-bp@alien8.deSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

Reported by syzkaller:

   BUG: unable to handle kernel paging request at ffffffffc07f6a2e
   IP: report_bug+0x94/0x120
   PGD 348e12067
   P4D 348e12067
   PUD 348e14067
   PMD 3cbd84067
   PTE 80000003f7e87161

   Oops: 0003 [#1] SMP
   CPU: 2 PID: 7091 Comm: kvm_load_guest_ Tainted: G           OE   4.11.0+ #8
   task: ffff92fdfb525400 task.stack: ffffbda6c3d04000
   RIP: 0010:report_bug+0x94/0x120
   RSP: 0018:ffffbda6c3d07b20 EFLAGS: 00010202
    do_trap+0x156/0x170
    do_error_trap+0xa3/0x170
    ? kvm_load_guest_fpu.part.175+0x12a/0x170 [kvm]
    ? mark_held_locks+0x79/0xa0
    ? retint_kernel+0x10/0x10
    ? trace_hardirqs_off_thunk+0x1a/0x1c
    do_invalid_op+0x20/0x30
    invalid_op+0x1e/0x30
   RIP: 0010:kvm_load_guest_fpu.part.175+0x12a/0x170 [kvm]
    ? kvm_load_guest_fpu.part.175+0x1c/0x170 [kvm]
    kvm_arch_vcpu_ioctl_run+0xed6/0x1b70 [kvm]
    kvm_vcpu_ioctl+0x384/0x780 [kvm]
    ? kvm_vcpu_ioctl+0x384/0x780 [kvm]
    ? sched_clock+0x13/0x20
    ? __do_page_fault+0x2a0/0x550
    do_vfs_ioctl+0xa4/0x700
    ? up_read+0x1f/0x40
    ? __do_page_fault+0x2a0/0x550
    SyS_ioctl+0x79/0x90
    entry_SYSCALL_64_fastpath+0x23/0xc2

SDM mentioned that "The MXCSR has several reserved bits, and attempting to write
a 1 to any of these bits will cause a general-protection exception(#GP) to be
generated". The syzkaller forks' testcase overrides xsave area w/ random values
and steps on the reserved bits of MXCSR register. The damaged MXCSR register
values of guest will be restored to SSEx MXCSR register before vmentry. This
patch fixes it by catching userspace override MXCSR register reserved bits w/
random values and bails out immediately.
Reported-by: NAndrey Konovalov <andreyknvl@google.com>
Reviewed-by: NPaolo Bonzini <pbonzini@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: NWanpeng Li <wanpeng.li@hotmail.com>
Signed-off-by: NRadim Krčmář <rkrcmar@redhat.com>

Cc: Tigran Aivazian <aivazian.tigran@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

When running as Xen pv guest X86_BUG_SYSRET_SS_ATTRS must not be set
on AMD cpus.

This bug/feature bit is kind of special as it will be used very early
when switching threads. Setting the bit and clearing it a little bit
later leaves a critical window where things can go wrong. This time
window has enlarged a little bit by using setup_clear_cpu_cap() instead
of the hypervisor's set_cpu_features callback. It seems this larger
window now makes it rather easy to hit the problem.

The proper solution is to never set the bit in case of Xen.
Signed-off-by: NJuergen Gross <jgross@suse.com>
Reviewed-by: NBoris Ostrovsky <boris.ostrovsky@oracle.com>
Acked-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NJuergen Gross <jgross@suse.com>

This partially reverts commit:

  23b2a4dd ("x86/boot/32: Defer resyncing initial_page_table until per-cpu is set up")

That commit had one definite bug and one potential bug.  The
definite bug is that setup_per_cpu_areas() uses a differnet generic
implementation on UP kernels, so initial_page_table never got
resynced.  This was fine for access to percpu data (it's in the
identity map on UP), but it breaks other users of
initial_page_table.  The potential bug is that helpers like
efi_init() would be called before the tables were synced.

Avoid both problems by just syncing the page tables in setup_arch()
*and* setup_per_cpu_areas().
Reported-by: NJan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: NAndy Lutomirski <luto@kernel.org>
Cc: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Garnier <thgarnie@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Signed-off-by: NIngo Molnar <mingo@kernel.org>

Now that all call sites, completely decouple cacheflush.h and
set_memory.h

[sfr@canb.auug.org.au: kprobes/x86: merge fix for set_memory.h decoupling]
  Link: http://lkml.kernel.org/r/20170418180903.10300fd3@canb.auug.org.au
Link: http://lkml.kernel.org/r/1488920133-27229-17-git-send-email-labbott@redhat.comSigned-off-by: NLaura Abbott <labbott@redhat.com>
Signed-off-by: NStephen Rothwell <sfr@canb.auug.org.au>
Acked-by: NCatalin Marinas <catalin.marinas@arm.com>
Acked-by: NMark Rutland <mark.rutland@arm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

set_memory_* functions have moved to set_memory.h.  Switch to this
explicitly.

Link: http://lkml.kernel.org/r/1488920133-27229-6-git-send-email-labbott@redhat.comSigned-off-by: NLaura Abbott <labbott@redhat.com>
Acked-by: NIngo Molnar <mingo@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

__vmalloc* allows users to provide gfp flags for the underlying
allocation.  This API is quite popular

  $ git grep "=[[:space:]]__vmalloc\|return[[:space:]]*__vmalloc" | wc -l
  77

The only problem is that many people are not aware that they really want
to give __GFP_HIGHMEM along with other flags because there is really no
reason to consume precious lowmemory on CONFIG_HIGHMEM systems for pages
which are mapped to the kernel vmalloc space.  About half of users don't
use this flag, though.  This signals that we make the API unnecessarily
too complex.

This patch simply uses __GFP_HIGHMEM implicitly when allocating pages to
be mapped to the vmalloc space.  Current users which add __GFP_HIGHMEM
are simplified and drop the flag.

Link: http://lkml.kernel.org/r/20170307141020.29107-1-mhocko@kernel.orgSigned-off-by: NMichal Hocko <mhocko@suse.com>
Reviewed-by: NMatthew Wilcox <mawilcox@microsoft.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: David Rientjes <rientjes@google.com>
Cc: Cristopher Lameter <cl@linux.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Kexec sets up all identity mappings before booting into the new
kernel, and this will cause extra memory consumption for paging
structures which is quite considerable on modern machines with
huge memory sizes.

E.g. on a 32TB machine that is kdumping, it could waste around
128MB (around 4MB/TB) from the reserved memory after kexec sets
all the identity mappings using the current 2MB page.

Add to that the memory needed for the loaded kdump kernel, initramfs,
etc., and it causes a kexec syscall -NOMEM failure.

As a result, we had to enlarge reserved memory via "crashkernel=X"
to work around this problem.

This causes some trouble for distributions that use policies
to evaluate the proper "crashkernel=X" value for users.

So enable gbpages for kexec mappings.
Signed-off-by: NXunlei Pang <xlpang@redhat.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: akpm@linux-foundation.org
Cc: kexec@lists.infradead.org
Link: http://lkml.kernel.org/r/1493862171-8799-2-git-send-email-xlpang@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

Kernel identity mappings on x86-64 kernels are created in two
ways: by the early x86 boot code, or by kernel_ident_mapping_init().

Native kernels (which is the dominant usecase) use the former,
but the kexec and the hibernation code uses kernel_ident_mapping_init().

There's a subtle difference between these two ways of how identity
mappings are created, the current kernel_ident_mapping_init() code
creates identity mappings always using 2MB page(PMD level) - while
the native kernel boot path also utilizes gbpages where available.

This difference is suboptimal both for performance and for memory
usage: kernel_ident_mapping_init() needs to allocate pages for the
page tables when creating the new identity mappings.

This patch adds 1GB page(PUD level) support to kernel_ident_mapping_init()
to address these concerns.

The primary advantage would be better TLB coverage/performance,
because we'd utilize 1GB TLBs instead of 2MB ones.

It is also useful for machines with large number of memory to
save paging structure allocations(around 4MB/TB using 2MB page)
when setting identity mappings for all the memory, after using
1GB page it will consume only 8KB/TB.

( Note that this change alone does not activate gbpages in kexec,
  we are doing that in a separate patch. )
Signed-off-by: NXunlei Pang <xlpang@redhat.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: akpm@linux-foundation.org
Cc: kexec@lists.infradead.org
Link: http://lkml.kernel.org/r/1493862171-8799-1-git-send-email-xlpang@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

There is no user of x86_hyper->set_cpu_features() any more. Remove it.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: x86@kernel.org
Signed-off-by: NJuergen Gross <jgross@suse.com>
Reviewed-by: NBoris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: NJuergen Gross <jgross@suse.com>

There is no need to set the same capabilities for each cpu
individually. This can be done for all cpus in platform initialization.

Cc: Alok Kataria <akataria@vmware.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: x86@kernel.org
Cc: virtualization@lists.linux-foundation.org
Signed-off-by: NJuergen Gross <jgross@suse.com>
Reviewed-by: NBoris Ostrovsky <boris.ostrovsky@oracle.com>
Acked-by: NAlok Kataria <akataria@vmware.com>
Signed-off-by: NJuergen Gross <jgross@suse.com>

All code to support Xen PV will get under this new option. For the
beginning, check for it in the common code.
Signed-off-by: NVitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: NJuergen Gross <jgross@suse.com>
Signed-off-by: NJuergen Gross <jgross@suse.com>

As a preparation to splitting the code we need to untangle it:

x86_hyper_xen -> x86_hyper_xen_hvm and x86_hyper_xen_pv
xen_platform() -> xen_platform_hvm() and xen_platform_pv()
xen_cpu_up_prepare() -> xen_cpu_up_prepare_pv() and xen_cpu_up_prepare_hvm()
xen_cpu_dead() -> xen_cpu_dead_pv() and xen_cpu_dead_pv_hvm()

Add two parameters to xen_cpuhp_setup() to pass proper cpu_up_prepare and
cpu_dead hooks. xen_set_cpu_features() is now PV-only so the redundant
xen_pv_domain() check can be dropped.
Signed-off-by: NVitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: NJuergen Gross <jgross@suse.com>
Signed-off-by: NJuergen Gross <jgross@suse.com>

IOMMU harms performance signficantly when we run very fast networking
workloads. It's 40GB networking doing XDP test. Software overhead is
almost unaware, but it's the IOTLB miss (based on our analysis) which
kills the performance. We observed the same performance issue even with
software passthrough (identity mapping), only the hardware passthrough
survives. The pps with iommu (with software passthrough) is only about
~30% of that without it. This is a limitation in hardware based on our
observation, so we'd like to disable the IOMMU force on, but we do want
to use TBOOT and we can sacrifice the DMA security bought by IOMMU. I
must admit I know nothing about TBOOT, but TBOOT guys (cc-ed) think not
eabling IOMMU is totally ok.

So introduce a new boot option to disable the force on. It's kind of
silly we need to run into intel_iommu_init even without force on, but we
need to disable TBOOT PMR registers. For system without the boot option,
nothing is changed.
Signed-off-by: NShaohua Li <shli@fb.com>
Signed-off-by: NJoerg Roedel <jroedel@suse.de>

mark_screen_rdonly() is the last remaining caller of flush_tlb().
flush_tlb_mm_range() is potentially faster and isn't obsolete.

Compile-tested only because I don't know whether software that uses
this mechanism even exists.
Signed-off-by: NAndy Lutomirski <luto@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Nadav Amit <namit@vmware.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/791a644076fc3577ba7f7b7cafd643cc089baa7d.1492844372.git.luto@kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

Currently unwind_dump() dumps only the most recently accessed stack.
But it has a few issues.

In some cases, 'first_sp' can get out of sync with 'stack_info', causing
unwind_dump() to start from the wrong address, flood the printk buffer,
and eventually read a bad address.

In other cases, dumping only the most recently accessed stack doesn't
give enough data to diagnose the error.

Fix both issues by dumping *all* stacks involved in the trace, not just
the last one.
Signed-off-by: NJosh Poimboeuf <jpoimboe@redhat.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: 8b5e99f0 ("x86/unwind: Dump stack data on warnings")
Link: http://lkml.kernel.org/r/016d6a9810d7d1bfc87ef8c0e6ee041c6744c909.1493171120.git.jpoimboe@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

Borislav Petkov reported the following unwinder warning:

  WARNING: kernel stack regs at ffffc9000024fea8 in udevadm:92 has bad 'bp' value 00007fffc4614d30
  unwind stack type:0 next_sp:          (null) mask:0x6 graph_idx:0
  ffffc9000024fea8: 000055a6100e9b38 (0x55a6100e9b38)
  ffffc9000024feb0: 000055a6100e9b35 (0x55a6100e9b35)
  ffffc9000024feb8: 000055a6100e9f68 (0x55a6100e9f68)
  ffffc9000024fec0: 000055a6100e9f50 (0x55a6100e9f50)
  ffffc9000024fec8: 00007fffc4614d30 (0x7fffc4614d30)
  ffffc9000024fed0: 000055a6100eaf50 (0x55a6100eaf50)
  ffffc9000024fed8: 0000000000000000 ...
  ffffc9000024fee0: 0000000000000100 (0x100)
  ffffc9000024fee8: ffff8801187df488 (0xffff8801187df488)
  ffffc9000024fef0: 00007ffffffff000 (0x7ffffffff000)
  ffffc9000024fef8: 0000000000000000 ...
  ffffc9000024ff10: ffffc9000024fe98 (0xffffc9000024fe98)
  ffffc9000024ff18: 00007fffc4614d00 (0x7fffc4614d00)
  ffffc9000024ff20: ffffffffffffff10 (0xffffffffffffff10)
  ffffc9000024ff28: ffffffff811c6c1f (SyS_newlstat+0xf/0x10)
  ffffc9000024ff30: 0000000000000010 (0x10)
  ffffc9000024ff38: 0000000000000296 (0x296)
  ffffc9000024ff40: ffffc9000024ff50 (0xffffc9000024ff50)
  ffffc9000024ff48: 0000000000000018 (0x18)
  ffffc9000024ff50: ffffffff816b2e6a (entry_SYSCALL_64_fastpath+0x18/0xa8)
  ...

It unwinded from an interrupt which came in right after entry code
called into a C syscall handler, before it had a chance to set up the
frame pointer, so regs->bp still had its user space value.

Add a check to silence warnings in such a case, where an interrupt
has occurred and regs->sp is almost at the end of the stack.
Reported-by: NBorislav Petkov <bp@suse.de>
Tested-by: NBorislav Petkov <bp@suse.de>
Signed-off-by: NJosh Poimboeuf <jpoimboe@redhat.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: c32c47c6 ("x86/unwind: Warn on bad frame pointer")
Link: http://lkml.kernel.org/r/c695f0d0d4c2cfe6542b90e2d0520e11eb901eb5.1493171120.git.jpoimboe@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

Fengguang Wu's zero day bot triggered a stack unwinder dump. This can
be easily triggered when CONFIG_FRAME_POINTERS is enabled and -mfentry
is in use on x86_32.

 ># cd /sys/kernel/debug/tracing
 ># echo 'p:schedule schedule' > kprobe_events
 ># echo stacktrace > events/kprobes/schedule/trigger

This is because the code that implemented fentry in the ftrace_regs_caller
tried to use the least amount of #ifdefs, and modified ebp when
CC_USE_FENTRY was defined to point to the parent ip as it does when
CC_USE_FENTRY is not defined. But when CONFIG_FRAME_POINTERS is set, it
corrupts the ebp register for this frame while doing the tracing.

NOTE, it does not corrupt ebp in any other way. It is just a bad frame
pointer when calling into the tracing infrastructure. The original ebp is
restored before returning from the fentry call. But if a stack trace is
performed inside the tracing, the unwinder will notice the bad ebp.

Instead of toying with ebp with CC_USING_FENTRY, just slap the parent ip
into the second parameter (%edx), and have an #else that does it the
original way.

The unwinder will unfortunately miss the function being traced, as the
stack frame is not set up yet for it, as it is for x86_64. But fixing that
is a bit more complex and did not work before anyway.

This has been tested with and without FRAME_POINTERS being set while using
-mfentry, as well as using an older compiler that uses mcount.
Analyzed-by: NJosh Poimboeuf <jpoimboe@redhat.com>
Fixes: 644e0e8d ("x86/ftrace: Add -mfentry support to x86_32 with DYNAMIC_FTRACE set")
Reported-by: Nkernel test robot <fengguang.wu@intel.com>
Signed-off-by: NSteven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lists.01.org/pipermail/lkp/2017-April/006165.html
Link: http://lkml.kernel.org/r/20170420172236.7af7f6e5@gandalf.local.homeSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

When schemata parses the resource names it does not return an error if it
detects incorrect resource names and fails quietly.

This happens because for_each_enabled_rdt_resource(r) leaves "r" pointing
beyond the end of the rdt_resources_all[] array, and the check for !r->name
results in an out of bounds access.

Split the resource parsing part into a helper function to avoid the issue.

[ tglx: Made it readable by splitting the parser loop out into a function ]
Reported-by: NPrakhya, Sai Praneeth <sai.praneeth.prakhya@intel.com>
Signed-off-by: NVikas Shivappa <vikas.shivappa@linux.intel.com>
Tested-by: NPrakhya, Sai Praneeth <sai.praneeth.prakhya@intel.com>
Cc: fenghua.yu@intel.com
Cc: tony.luck@intel.com
Cc: ravi.v.shankar@intel.com
Cc: vikas.shivappa@intel.com
Link: http://lkml.kernel.org/r/1492645804-17465-4-git-send-email-vikas.shivappa@linux.intel.comSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

Schemata is displayed in tabular format which introduces some whitespace
to show data in a tabular format.

Writing back the same data fails as the parser does not handle the
whitespace.

Trim the leading and trailing whitespace before parsing.
Reported-by: NPrakhya, Sai Praneeth <sai.praneeth.prakhya@intel.com>
Signed-off-by: NVikas Shivappa <vikas.shivappa@linux.intel.com>
Tested-by: NPrakhya, Sai Praneeth <sai.praneeth.prakhya@intel.com>
Cc: fenghua.yu@intel.com
Cc: tony.luck@intel.com
Cc: ravi.v.shankar@intel.com
Cc: vikas.shivappa@intel.com
Link: http://lkml.kernel.org/r/1492645804-17465-3-git-send-email-vikas.shivappa@linux.intel.comSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

Currently max width of 'resource name' and 'resource data' is being
initialized based on 'enabled resources' during boot. But the mount can
enable different capable resources at a later time which upsets the
tabular format of schemata. Fix this to be based on 'all capable'
resources.
Signed-off-by: NVikas Shivappa <vikas.shivappa@linux.intel.com>
Tested-by: NPrakhya, Sai Praneeth <sai.praneeth.prakhya@intel.com>
Cc: fenghua.yu@intel.com
Cc: tony.luck@intel.com
Cc: ravi.v.shankar@intel.com
Cc: vikas.shivappa@intel.com
Link: http://lkml.kernel.org/r/1492645804-17465-2-git-send-email-vikas.shivappa@linux.intel.comSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

Before offlining a CPU its required to check whether there are enough free
irq vectors available so interrupts can be migrated away from the CPU.

This check is executed whether its required or not and neither stops
searching when the number of required free vectors are reached.

Bypass the free vector check if the current CPU has no irq to migrate and
leave the for_each_online_cpu() loop when the free vector count reaches the
number of required vectors.
Suggested-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NChen Yu <yu.c.chen@intel.com>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Len Brown <lenb@kernel.orq>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Link: http://lkml.kernel.org/r/1492357410-510-1-git-send-email-yu.c.chen@intel.comSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

Modify the reschedule warning to output the offline CPU number and
use a better debug message.
Signed-off-by: NPrarit Bhargava <prarit@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Daniel Bristot de Oliveira <bristot@redhat.com>
Cc: Hidehiro Kawai <hidehiro.kawai.ez@hitachi.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Wanpeng Li <wanpeng.li@hotmail.com>
Link: http://lkml.kernel.org/r/1492518305-3808-1-git-send-email-prarit@redhat.com
[ Tweaked the warning message. ]
Signed-off-by: NIngo Molnar <mingo@kernel.org>

A CPU in VMX root mode will ignore INIT signals and will fail to bring
up the APs after reboot.  Therefore, on a panic we disable VMX on all
CPUs before rebooting or triggering kdump.

Do this when halting the machine as well, in case a firmware-level reboot
does not perform a cold reset for all processors.  Without doing this,
rebooting the host may hang.
Signed-off-by: NTiantian Feng <fengtiantian@huawei.com>
Signed-off-by: NXishi Qiu <qiuxishi@huawei.com>
[ Rewritten commit message. ]
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: kvm@vger.kernel.org
Link: http://lkml.kernel.org/r/20170419161839.30550-1-pbonzini@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

mce_usable_address() does a bunch of basic sanity checks to verify
whether the address reported with the error is usable for further
processing. However, we do check MCi_STATUS[MISCV] and that is not
needed on AMD as that bit says that there's additional information about
the logged error in the MCi_MISCj banks.

But we don't need that to know whether the address is usable - we only
need to know whether the physical address is valid - i.e., ADDRV.

On Intel the MISCV bit is needed to perform additional checks to determine
whether the reported address is a physical one, etc.
Signed-off-by: NBorislav Petkov <bp@suse.de>
Cc: Yazen Ghannam <yazen.ghannam@amd.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: linux-edac <linux-edac@vger.kernel.org>
Link: http://lkml.kernel.org/r/20170418183924.6agjkebilwqj26or@pd.tnicSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

The 'sp' parameter to unwind_dump() is unused.  Remove it.
Signed-off-by: NJosh Poimboeuf <jpoimboe@redhat.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/08cb36b004629f6bbcf44c267ae4a609242ebd0b.1492520933.git.jpoimboe@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

In unwind_dump(), the stack mask value is printed in hex, but is
confusingly not prepended with '0x'.
Signed-off-by: NJosh Poimboeuf <jpoimboe@redhat.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/e7fe41be19d73c9f99f53082486473febfe08ffa.1492520933.git.jpoimboe@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

On x86-32, 32-bit stack values printed by unwind_dump() are confusingly
zero-padded to 16 characters (64 bits):

  unwind stack type:0 next_sp:  (null) mask:a graph_idx:0
  f50cdebc: 00000000f50cdec4 (0xf50cdec4)
  f50cdec0: 00000000c40489b7 (irq_exit+0x87/0xa0)
  ...

Instead, base the field width on the size of a long integer so that it
looks right on both x86-32 and x86-64.

x86-32:

  unwind stack type:1 next_sp:  (null) mask:0x2 graph_idx:0
  c0ee9d98: c0ee9de0 (init_thread_union+0x1de0/0x2000)
  c0ee9d9c: c043fd90 (__save_stack_trace+0x50/0xe0)
  ...

x86-64:

  unwind stack type:1 next_sp:          (null) mask:0x2 graph_idx:0
  ffffffff81e03b88: ffffffff81e03c10 (init_thread_union+0x3c10/0x4000)
  ffffffff81e03b90: ffffffff81048f8e (__save_stack_trace+0x5e/0x100)
  ...
Reported-by: NH. Peter Anvin <hpa@zytor.com>
Signed-off-by: NJosh Poimboeuf <jpoimboe@redhat.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/36b743812e7eb291d74af4e5067736736622daad.1492520933.git.jpoimboe@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

For pre-4.6.0 versions of GCC, which don't have '-mfentry', the
'-maccumulate-outgoing-args' option is required for function graph
tracing in order to avoid GCC bug 42109.

However, GCC ignores '-maccumulate-outgoing-args' when '-Os' is
also set.

Currently we force a build error to prevent that scenario, but that
breaks randconfigs.  So change the error to a warning which also
disables CONFIG_CC_OPTIMIZE_FOR_SIZE.
Reported-by: NAndi Kleen <andi@firstfloor.org>
Signed-off-by: NJosh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: kbuild test robot <fengguang.wu@intel.com>
Cc: kbuild-all@01.org
Link: http://lkml.kernel.org/r/20170418214429.o7fbwbmf4nqosezy@trebleSigned-off-by: NIngo Molnar <mingo@kernel.org>