Commit graph

25474 commits

Author SHA1 Message Date
Thomas Gleixner 990e9dc381 x86/ldt: Make all size computations unsigned
ldt->size can never be negative. The helper functions take 'unsigned int'
arguments which are assigned from ldt->size. The related user space
user_desc struct member entry_number is unsigned as well.

But ldt->size itself and a few local variables which are related to
ldt->size are type 'int' which makes no sense whatsoever and results in
typecasts which make the eyes bleed.

Clean it up and convert everything which is related to ldt->size to
unsigned it.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
2016-12-10 00:24:39 +01:00
Dan Carpenter 296dc5806d x86/ldt: Make a size argument unsigned
My static checker complains that we put an upper bound on the "size"
argument but not a lower bound.  The checker is not smart enough to know
the possible ranges of "old_mm->context.ldt->size" from
init_new_context_ldt() so it thinks maybe it could be negative.

Let's make it unsigned to silence the warning and future proof the code
a bit.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Andy Lutomirski <luto@kernel.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: kernel-janitors@vger.kernel.org
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20161208105602.GA11382@elgon.mountain
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-12-10 00:24:39 +01:00
Linus Torvalds ea5a9eff96 Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 fixes from Ingo Molnar:
 "Misc fixes: a core dumping crash fix, a guess-unwinder regression fix,
  plus three build warning fixes"

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/unwind: Fix guess-unwinder regression
  x86/build: Annotate die() with noreturn to fix build warning on clang
  x86/platform/olpc: Fix resume handler build warning
  x86/apic/uv: Silence a shift wrapping warning
  x86/coredump: Always use user_regs_struct for compat_elf_gregset_t
2016-12-07 11:39:27 -08:00
Peter Zijlstra (Intel) 7f612a7f0b perf/x86: Fix full width counter, counter overflow
Lukasz reported that perf stat counters overflow handling is broken on KNL/SLM.

Both these parts have full_width_write set, and that does indeed have
a problem. In order to deal with counter wrap, we must sample the
counter at at least half the counter period (see also the sampling
theorem) such that we can unambiguously reconstruct the count.

However commit:

  069e0c3c40 ("perf/x86/intel: Support full width counting")

sets the sampling interval to the full period, not half.

Fixing that exposes another issue, in that we must not sign extend the
delta value when we shift it right; the counter cannot have
decremented after all.

With both these issues fixed, counter overflow functions correctly
again.

Reported-by: Lukasz Odzioba <lukasz.odzioba@intel.com>
Tested-by: Liang, Kan <kan.liang@intel.com>
Tested-by: Odzioba, Lukasz <lukasz.odzioba@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: stable@vger.kernel.org
Fixes: 069e0c3c40 ("perf/x86/intel: Support full width counting")
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-12-06 09:44:28 +01:00
Piotr Luc 1dba23b12f perf/x86/intel: Enable C-state residency events for Knights Mill
The Knights Mill is enough close to Knights Landing so the path reuses
C-state residency support of the latter.

Signed-off-by: Piotr Luc <piotr.luc@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Link: http://lkml.kernel.org/r/20161201000853.18260-1-piotr.luc@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-12-06 09:44:27 +01:00
Josh Poimboeuf 55f856e640 x86/unwind: Fix guess-unwinder regression
My attempt at fixing some KASAN false positive warnings was rather brain
dead, and it broke the guess unwinder.  With frame pointers disabled,
/proc/<pid>/stack is broken:

  # cat /proc/1/stack
  [<ffffffffffffffff>] 0xffffffffffffffff

Restore the code flow to more closely resemble its previous state, while
still using READ_ONCE_NOCHECK() macros to silence KASAN false positives.

Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: c2d75e03d6 ("x86/unwind: Prevent KASAN false positive warnings in guess unwinder")
Link: http://lkml.kernel.org/r/b824f92c2c22eca5ec95ac56bd2a7c84cf0b9df9.1480309971.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-11-28 07:47:54 +01:00
Peter Foley adee8705d2 x86/build: Annotate die() with noreturn to fix build warning on clang
Fixes below warning with clang:

  In file included from ../arch/x86/tools/relocs_64.c:17:
  ../arch/x86/tools/relocs.c:977:6: warning: variable 'do_reloc' is used uninitialized whenever 'if' condition is false [-Wsometimes-uninitialized]

Signed-off-by: Peter Foley <pefoley2@pefoley.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/20161126222229.673-1-pefoley2@pefoley.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-11-28 07:47:22 +01:00
Borislav Petkov 20ab667771 x86/platform/olpc: Fix resume handler build warning
Fix:

  arch/x86/platform/olpc/olpc-xo15-sci.c:199:12: warning: ‘xo15_sci_resume’
  defined but not used [-Wunused-function]
   static int xo15_sci_resume(struct device *dev)
              ^

which I see in randconfig builds here.

Signed-off-by: Borislav 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/20161126142706.13602-1-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-11-28 07:46:03 +01:00
Linus Torvalds fc13ca191e KVM fixes for v4.9-rc7
Four fixes for bugs found by syzkaller on x86, all for stable.
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

Pull KVM fixes from Radim Krčmář:
 "Four fixes for bugs found by syzkaller on x86, all for stable"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
  KVM: x86: check for pic and ioapic presence before use
  KVM: x86: fix out-of-bounds accesses of rtc_eoi map
  KVM: x86: drop error recovery in em_jmp_far and em_ret_far
  KVM: x86: fix out-of-bounds access in lapic
2016-11-26 12:18:59 -08:00
Radim Krčmář df492896e6 KVM: x86: check for pic and ioapic presence before use
Split irqchip allows pic and ioapic routes to be used without them being
created, which results in NULL access.  Check for NULL and avoid it.
(The setup is too racy for a nicer solutions.)

Found by syzkaller:

  general protection fault: 0000 [#1] SMP DEBUG_PAGEALLOC KASAN
  Dumping ftrace buffer:
     (ftrace buffer empty)
  Modules linked in:
  CPU: 3 PID: 11923 Comm: kworker/3:2 Not tainted 4.9.0-rc5+ #27
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
  Workqueue: events irqfd_inject
  task: ffff88006a06c7c0 task.stack: ffff880068638000
  RIP: 0010:[...]  [...] __lock_acquire+0xb35/0x3380 kernel/locking/lockdep.c:3221
  RSP: 0000:ffff88006863ea20  EFLAGS: 00010006
  RAX: dffffc0000000000 RBX: dffffc0000000000 RCX: 0000000000000000
  RDX: 0000000000000039 RSI: 0000000000000000 RDI: 1ffff1000d0c7d9e
  RBP: ffff88006863ef58 R08: 0000000000000001 R09: 0000000000000000
  R10: 00000000000001c8 R11: 0000000000000000 R12: ffff88006a06c7c0
  R13: 0000000000000001 R14: ffffffff8baab1a0 R15: 0000000000000001
  FS:  0000000000000000(0000) GS:ffff88006d100000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: 00000000004abdd0 CR3: 000000003e2f2000 CR4: 00000000000026e0
  Stack:
   ffffffff894d0098 1ffff1000d0c7d56 ffff88006863ecd0 dffffc0000000000
   ffff88006a06c7c0 0000000000000000 ffff88006863ecf8 0000000000000082
   0000000000000000 ffffffff815dd7c1 ffffffff00000000 ffffffff00000000
  Call Trace:
   [...] lock_acquire+0x2a2/0x790 kernel/locking/lockdep.c:3746
   [...] __raw_spin_lock include/linux/spinlock_api_smp.h:144
   [...] _raw_spin_lock+0x38/0x50 kernel/locking/spinlock.c:151
   [...] spin_lock include/linux/spinlock.h:302
   [...] kvm_ioapic_set_irq+0x4c/0x100 arch/x86/kvm/ioapic.c:379
   [...] kvm_set_ioapic_irq+0x8f/0xc0 arch/x86/kvm/irq_comm.c:52
   [...] kvm_set_irq+0x239/0x640 arch/x86/kvm/../../../virt/kvm/irqchip.c:101
   [...] irqfd_inject+0xb4/0x150 arch/x86/kvm/../../../virt/kvm/eventfd.c:60
   [...] process_one_work+0xb40/0x1ba0 kernel/workqueue.c:2096
   [...] worker_thread+0x214/0x18a0 kernel/workqueue.c:2230
   [...] kthread+0x328/0x3e0 kernel/kthread.c:209
   [...] ret_from_fork+0x2a/0x40 arch/x86/entry/entry_64.S:433

Reported-by: Dmitry Vyukov <dvyukov@google.com>
Cc: stable@vger.kernel.org
Fixes: 49df6397ed ("KVM: x86: Split the APIC from the rest of IRQCHIP.")
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
2016-11-24 18:39:28 +01:00
Radim Krčmář 81cdb259fb KVM: x86: fix out-of-bounds accesses of rtc_eoi map
KVM was using arrays of size KVM_MAX_VCPUS with vcpu_id, but ID can be
bigger that the maximal number of VCPUs, resulting in out-of-bounds
access.

Found by syzkaller:

  BUG: KASAN: slab-out-of-bounds in __apic_accept_irq+0xb33/0xb50 at addr [...]
  Write of size 1 by task a.out/27101
  CPU: 1 PID: 27101 Comm: a.out Not tainted 4.9.0-rc5+ #49
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
   [...]
  Call Trace:
   [...] __apic_accept_irq+0xb33/0xb50 arch/x86/kvm/lapic.c:905
   [...] kvm_apic_set_irq+0x10e/0x180 arch/x86/kvm/lapic.c:495
   [...] kvm_irq_delivery_to_apic+0x732/0xc10 arch/x86/kvm/irq_comm.c:86
   [...] ioapic_service+0x41d/0x760 arch/x86/kvm/ioapic.c:360
   [...] ioapic_set_irq+0x275/0x6c0 arch/x86/kvm/ioapic.c:222
   [...] kvm_ioapic_inject_all arch/x86/kvm/ioapic.c:235
   [...] kvm_set_ioapic+0x223/0x310 arch/x86/kvm/ioapic.c:670
   [...] kvm_vm_ioctl_set_irqchip arch/x86/kvm/x86.c:3668
   [...] kvm_arch_vm_ioctl+0x1a08/0x23c0 arch/x86/kvm/x86.c:3999
   [...] kvm_vm_ioctl+0x1fa/0x1a70 arch/x86/kvm/../../../virt/kvm/kvm_main.c:3099

Reported-by: Dmitry Vyukov <dvyukov@google.com>
Cc: stable@vger.kernel.org
Fixes: af1bae5497 ("KVM: x86: bump KVM_MAX_VCPU_ID to 1023")
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
2016-11-24 18:37:19 +01:00
Radim Krčmář 2117d5398c KVM: x86: drop error recovery in em_jmp_far and em_ret_far
em_jmp_far and em_ret_far assumed that setting IP can only fail in 64
bit mode, but syzkaller proved otherwise (and SDM agrees).
Code segment was restored upon failure, but it was left uninitialized
outside of long mode, which could lead to a leak of host kernel stack.
We could have fixed that by always saving and restoring the CS, but we
take a simpler approach and just break any guest that manages to fail
as the error recovery is error-prone and modern CPUs don't need emulator
for this.

Found by syzkaller:

  WARNING: CPU: 2 PID: 3668 at arch/x86/kvm/emulate.c:2217 em_ret_far+0x428/0x480
  Kernel panic - not syncing: panic_on_warn set ...

  CPU: 2 PID: 3668 Comm: syz-executor Not tainted 4.9.0-rc4+ #49
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
   [...]
  Call Trace:
   [...] __dump_stack lib/dump_stack.c:15
   [...] dump_stack+0xb3/0x118 lib/dump_stack.c:51
   [...] panic+0x1b7/0x3a3 kernel/panic.c:179
   [...] __warn+0x1c4/0x1e0 kernel/panic.c:542
   [...] warn_slowpath_null+0x2c/0x40 kernel/panic.c:585
   [...] em_ret_far+0x428/0x480 arch/x86/kvm/emulate.c:2217
   [...] em_ret_far_imm+0x17/0x70 arch/x86/kvm/emulate.c:2227
   [...] x86_emulate_insn+0x87a/0x3730 arch/x86/kvm/emulate.c:5294
   [...] x86_emulate_instruction+0x520/0x1ba0 arch/x86/kvm/x86.c:5545
   [...] emulate_instruction arch/x86/include/asm/kvm_host.h:1116
   [...] complete_emulated_io arch/x86/kvm/x86.c:6870
   [...] complete_emulated_mmio+0x4e9/0x710 arch/x86/kvm/x86.c:6934
   [...] kvm_arch_vcpu_ioctl_run+0x3b7a/0x5a90 arch/x86/kvm/x86.c:6978
   [...] kvm_vcpu_ioctl+0x61e/0xdd0 arch/x86/kvm/../../../virt/kvm/kvm_main.c:2557
   [...] vfs_ioctl fs/ioctl.c:43
   [...] do_vfs_ioctl+0x18c/0x1040 fs/ioctl.c:679
   [...] SYSC_ioctl fs/ioctl.c:694
   [...] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:685
   [...] entry_SYSCALL_64_fastpath+0x1f/0xc2

Reported-by: Dmitry Vyukov <dvyukov@google.com>
Cc: stable@vger.kernel.org
Fixes: d1442d85cc ("KVM: x86: Handle errors when RIP is set during far jumps")
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
2016-11-24 18:36:54 +01:00
Radim Krčmář 444fdad88f KVM: x86: fix out-of-bounds access in lapic
Cluster xAPIC delivery incorrectly assumed that dest_id <= 0xff.
With enabled KVM_X2APIC_API_USE_32BIT_IDS in KVM_CAP_X2APIC_API, a
userspace can send an interrupt with dest_id that results in
out-of-bounds access.

Found by syzkaller:

  BUG: KASAN: slab-out-of-bounds in kvm_irq_delivery_to_apic_fast+0x11fa/0x1210 at addr ffff88003d9ca750
  Read of size 8 by task syz-executor/22923
  CPU: 0 PID: 22923 Comm: syz-executor Not tainted 4.9.0-rc4+ #49
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
   [...]
  Call Trace:
   [...] __dump_stack lib/dump_stack.c:15
   [...] dump_stack+0xb3/0x118 lib/dump_stack.c:51
   [...] kasan_object_err+0x1c/0x70 mm/kasan/report.c:156
   [...] print_address_description mm/kasan/report.c:194
   [...] kasan_report_error mm/kasan/report.c:283
   [...] kasan_report+0x231/0x500 mm/kasan/report.c:303
   [...] __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:329
   [...] kvm_irq_delivery_to_apic_fast+0x11fa/0x1210 arch/x86/kvm/lapic.c:824
   [...] kvm_irq_delivery_to_apic+0x132/0x9a0 arch/x86/kvm/irq_comm.c:72
   [...] kvm_set_msi+0x111/0x160 arch/x86/kvm/irq_comm.c:157
   [...] kvm_send_userspace_msi+0x201/0x280 arch/x86/kvm/../../../virt/kvm/irqchip.c:74
   [...] kvm_vm_ioctl+0xba5/0x1670 arch/x86/kvm/../../../virt/kvm/kvm_main.c:3015
   [...] vfs_ioctl fs/ioctl.c:43
   [...] do_vfs_ioctl+0x18c/0x1040 fs/ioctl.c:679
   [...] SYSC_ioctl fs/ioctl.c:694
   [...] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:685
   [...] entry_SYSCALL_64_fastpath+0x1f/0xc2

Reported-by: Dmitry Vyukov <dvyukov@google.com>
Cc: stable@vger.kernel.org
Fixes: e45115b62f ("KVM: x86: use physical LAPIC array for logical x2APIC")
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
2016-11-24 18:35:53 +01:00
Dan Carpenter c4597fd756 x86/apic/uv: Silence a shift wrapping warning
'm_io' is stored in 6 bits so it's a number in the 0-63 range.  Static
analysis tools complain that 1 << 63 will wrap so I have changed it to
1ULL << m_io.

This code is over three years old so presumably the bug doesn't happen
very frequently in real life or someone would have complained by now.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Alex Thorlton <athorlton@sgi.com>
Cc: Dimitri Sivanich <sivanich@sgi.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Travis <travis@sgi.com>
Cc: Nathan Zimmer <nzimmer@sgi.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: kernel-janitors@vger.kernel.org
Fixes: b15cc4a12b ("x86, uv, uv3: Update x2apic Support for SGI UV3")
Link: http://lkml.kernel.org/r/20161123221908.GA23997@mwanda
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-11-24 06:01:05 +01:00
Dmitry Safonov 7b2dd36828 x86/coredump: Always use user_regs_struct for compat_elf_gregset_t
Commit:

  90954e7b94 ("x86/coredump: Use pr_reg size, rather that TIF_IA32 flag")

changed the coredumping code to construct the elf coredump file according
to register set size - and that's good: if binary crashes with 32-bit code
selector, generate 32-bit ELF core, otherwise - 64-bit core.

That was made for restoring 32-bit applications on x86_64: we want
32-bit application after restore to generate 32-bit ELF dump on crash.

All was quite good and recently I started reworking 32-bit applications
dumping part of CRIU: now it has two parasites (32 and 64) for seizing
compat/native tasks, after rework it'll have one parasite, working in
64-bit mode, to which 32-bit prologue long-jumps during infection.

And while it has worked for my work machine, in VM with
!CONFIG_X86_X32_ABI during reworking I faced that segfault in 32-bit
binary, that has long-jumped to 64-bit mode results in dereference
of garbage:

 32-victim[19266]: segfault at f775ef65 ip 00000000f775ef65 sp 00000000f776aa50 error 14
 BUG: unable to handle kernel paging request at ffffffffffffffff
 IP: [<ffffffff81332ce0>] strlen+0x0/0x20
 [...]
 Call Trace:
  [] elf_core_dump+0x11a9/0x1480
  [] do_coredump+0xa6b/0xe60
  [] get_signal+0x1a8/0x5c0
  [] do_signal+0x23/0x660
  [] exit_to_usermode_loop+0x34/0x65
  [] prepare_exit_to_usermode+0x2f/0x40
  [] retint_user+0x8/0x10

That's because we have 64-bit registers set (with according total size)
and we're writing it to elf_thread_core_info which has smaller size
on !CONFIG_X86_X32_ABI. That lead to overwriting ELF notes part.

Tested on 32-, 64-bit ELF crashes and on 32-bit binaries that have
jumped with 64-bit code selector - all is readable with gdb.

Signed-off-by: Dmitry Safonov <dsafonov@virtuozzo.com>
Cc: Andy Lutomirski <luto@kernel.org>
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>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-mm@kvack.org
Fixes: 90954e7b94 ("x86/coredump: Use pr_reg size, rather that TIF_IA32 flag")
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-11-24 06:01:05 +01:00
Linus Torvalds ded9b5dd20 Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull perf fixes from Ingo Molnar:
 "Six fixes for bugs that were found via fuzzing, and a trivial
  hw-enablement patch for AMD Family-17h CPU PMUs"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf/x86/intel/uncore: Allow only a single PMU/box within an events group
  perf/x86/intel: Cure bogus unwind from PEBS entries
  perf/x86: Restore TASK_SIZE check on frame pointer
  perf/core: Fix address filter parser
  perf/x86: Add perf support for AMD family-17h processors
  perf/x86/uncore: Fix crash by removing bogus event_list[] handling for SNB client uncore IMC
  perf/core: Do not set cpuctx->cgrp for unscheduled cgroups
2016-11-23 08:09:21 -08:00
Linus Torvalds 7cfc4317ea Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 fixes from Ingo Molnar:
 "Misc fixes:
   - two fixes to make (very) old Intel CPUs boot reliably
   - fix the intel-mid driver and rename it
   - two KASAN false positive fixes
   - an FPU fix
   - two sysfb fixes
   - two build fixes related to new toolchain versions"

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/platform/intel-mid: Rename platform_wdt to platform_mrfld_wdt
  x86/build: Build compressed x86 kernels as PIE when !CONFIG_RELOCATABLE as well
  x86/platform/intel-mid: Register watchdog device after SCU
  x86/fpu: Fix invalid FPU ptrace state after execve()
  x86/boot: Fail the boot if !M486 and CPUID is missing
  x86/traps: Ignore high word of regs->cs in early_fixup_exception()
  x86/dumpstack: Prevent KASAN false positive warnings
  x86/unwind: Prevent KASAN false positive warnings in guess unwinder
  x86/boot: Avoid warning for zero-filling .bss
  x86/sysfb: Fix lfb_size calculation
  x86/sysfb: Add support for 64bit EFI lfb_base
2016-11-22 12:17:49 -08:00
Peter Zijlstra 033ac60c7f perf/x86/intel/uncore: Allow only a single PMU/box within an events group
Group validation expects all events to be of the same PMU; however
is_uncore_pmu() is too wide, it matches _all_ uncore events, even
across PMUs.

This triggers failure when we group different events from different
uncore PMUs, like:

  perf stat -vv -e '{uncore_cbox_0/config=0x0334/,uncore_qpi_0/event=1/}' -a sleep 1

Fix is_uncore_pmu() by only matching events to the box at hand.

Note that generic code; ran after this step; will disallow this
mixture of PMU events.

Reported-by: Jiri Olsa <jolsa@redhat.com>
Tested-by: Jiri Olsa <jolsa@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vince@deater.net>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Link: http://lkml.kernel.org/r/20161118125354.GQ3117@twins.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-11-22 12:36:59 +01:00
Peter Zijlstra b8000586c9 perf/x86/intel: Cure bogus unwind from PEBS entries
Vince Weaver reported that perf_fuzzer + KASAN detects that PEBS event
unwinds sometimes do 'weird' things. In particular, we seemed to be
ending up unwinding from random places on the NMI stack.

While it was somewhat expected that the event record BP,SP would not
match the interrupt BP,SP in that the interrupt is strictly later than
the record event, it was overlooked that it could be on an already
overwritten stack.

Therefore, don't copy the recorded BP,SP over the interrupted BP,SP
when we need stack unwinds.

Note that its still possible the unwind doesn't full match the actual
event, as its entirely possible to have done an (I)RET between record
and interrupt, but on average it should still point in the general
direction of where the event came from. Also, it's the best we can do,
considering.

The particular scenario that triggered the bogus NMI stack unwind was
a PEBS event with very short period, upon enabling the event at the
tail of the PMI handler (FREEZE_ON_PMI is not used), it instantly
triggers a record (while still on the NMI stack) which in turn
triggers the next PMI. This then causes back-to-back NMIs and we'll
try and unwind the stack-frame from the last NMI, which obviously is
now overwritten by our own.

Analyzed-by: Josh Poimboeuf <jpoimboe@redhat.com>
Reported-by: Vince Weaver <vincent.weaver@maine.edu>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@gmail.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: davej@codemonkey.org.uk <davej@codemonkey.org.uk>
Cc: dvyukov@google.com <dvyukov@google.com>
Cc: stable@vger.kernel.org
Fixes: ca037701a0 ("perf, x86: Add PEBS infrastructure")
Link: http://lkml.kernel.org/r/20161117171731.GV3157@twins.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-11-22 12:36:58 +01:00
Johannes Weiner ae31fe51a3 perf/x86: Restore TASK_SIZE check on frame pointer
The following commit:

  75925e1ad7 ("perf/x86: Optimize stack walk user accesses")

... switched from copy_from_user_nmi() to __copy_from_user_nmi() with a manual
access_ok() check.

Unfortunately, copy_from_user_nmi() does an explicit check against TASK_SIZE,
whereas the access_ok() uses whatever the current address limit of the task is.

We are getting NMIs when __probe_kernel_read() has switched to KERNEL_DS, and
then see vmalloc faults when we access what looks like pointers into vmalloc
space:

  [] WARNING: CPU: 3 PID: 3685731 at arch/x86/mm/fault.c:435 vmalloc_fault+0x289/0x290
  [] CPU: 3 PID: 3685731 Comm: sh Tainted: G        W       4.6.0-5_fbk1_223_gdbf0f40 #1
  [] Call Trace:
  []  <NMI>  [<ffffffff814717d1>] dump_stack+0x4d/0x6c
  []  [<ffffffff81076e43>] __warn+0xd3/0xf0
  []  [<ffffffff81076f2d>] warn_slowpath_null+0x1d/0x20
  []  [<ffffffff8104a899>] vmalloc_fault+0x289/0x290
  []  [<ffffffff8104b5a0>] __do_page_fault+0x330/0x490
  []  [<ffffffff8104b70c>] do_page_fault+0xc/0x10
  []  [<ffffffff81794e82>] page_fault+0x22/0x30
  []  [<ffffffff81006280>] ? perf_callchain_user+0x100/0x2a0
  []  [<ffffffff8115124f>] get_perf_callchain+0x17f/0x190
  []  [<ffffffff811512c7>] perf_callchain+0x67/0x80
  []  [<ffffffff8114e750>] perf_prepare_sample+0x2a0/0x370
  []  [<ffffffff8114e840>] perf_event_output+0x20/0x60
  []  [<ffffffff8114aee7>] ? perf_event_update_userpage+0xc7/0x130
  []  [<ffffffff8114ea01>] __perf_event_overflow+0x181/0x1d0
  []  [<ffffffff8114f484>] perf_event_overflow+0x14/0x20
  []  [<ffffffff8100a6e3>] intel_pmu_handle_irq+0x1d3/0x490
  []  [<ffffffff8147daf7>] ? copy_user_enhanced_fast_string+0x7/0x10
  []  [<ffffffff81197191>] ? vunmap_page_range+0x1a1/0x2f0
  []  [<ffffffff811972f1>] ? unmap_kernel_range_noflush+0x11/0x20
  []  [<ffffffff814f2056>] ? ghes_copy_tofrom_phys+0x116/0x1f0
  []  [<ffffffff81040d1d>] ? x2apic_send_IPI_self+0x1d/0x20
  []  [<ffffffff8100411d>] perf_event_nmi_handler+0x2d/0x50
  []  [<ffffffff8101ea31>] nmi_handle+0x61/0x110
  []  [<ffffffff8101ef94>] default_do_nmi+0x44/0x110
  []  [<ffffffff8101f13b>] do_nmi+0xdb/0x150
  []  [<ffffffff81795187>] end_repeat_nmi+0x1a/0x1e
  []  [<ffffffff8147daf7>] ? copy_user_enhanced_fast_string+0x7/0x10
  []  [<ffffffff8147daf7>] ? copy_user_enhanced_fast_string+0x7/0x10
  []  [<ffffffff8147daf7>] ? copy_user_enhanced_fast_string+0x7/0x10
  []  <<EOE>>  <IRQ>  [<ffffffff8115d05e>] ? __probe_kernel_read+0x3e/0xa0

Fix this by moving the valid_user_frame() check to before the uaccess
that loads the return address and the pointer to the next frame.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: linux-kernel@vger.kernel.org
Fixes: 75925e1ad7 ("perf/x86: Optimize stack walk user accesses")
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-11-22 12:36:58 +01:00
Andy Shevchenko e5dce28688 x86/platform/intel-mid: Rename platform_wdt to platform_mrfld_wdt
Rename the watchdog platform library file to explicitly show that is used only
on Intel Merrifield platforms.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.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/20161118172723.179761-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-11-21 11:07:11 +01:00
H.J. Lu a980ce352f x86/build: Build compressed x86 kernels as PIE when !CONFIG_RELOCATABLE as well
Since the bootloader may load the compressed x86 kernel at any address,
it should always be built as PIE, not just when CONFIG_RELOCATABLE=y.

Otherwise, linker in binutils 2.27 will optimize GOT load into the
absolute address when building the compressed x86 kernel as a non-PIE
executable.

Signed-off-by: H.J. Lu <hjl.tools@gmail.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: 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: linux-kernel@vger.kernel.org
[ Small wording changes. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-11-21 11:05:28 +01:00
Andy Shevchenko 8c5c86fb6a x86/platform/intel-mid: Register watchdog device after SCU
Watchdog device in Intel Tangier relies on SCU to be present. It uses the SCU
IPC channel to send commands and receive responses. If watchdog driver is
initialized quite before SCU and a command has been sent the result is always
an error like the following:

	intel_mid_wdt: Error stopping watchdog: 0xffffffed

Register watchdog device whne SCU is ready to avoid described issue.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.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/20161118165224.175514-1-andriy.shevchenko@linux.intel.com
[ Small cleanups. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-11-21 10:59:14 +01:00
Yu-cheng Yu b22cbe404a x86/fpu: Fix invalid FPU ptrace state after execve()
Robert O'Callahan reported that after an execve PTRACE_GETREGSET
NT_X86_XSTATE continues to return the pre-exec register values
until the exec'ed task modifies FPU state.

The test code is at:

  https://bugzilla.redhat.com/attachment.cgi?id=1164286.

What is happening is fpu__clear() does not properly clear fpstate.
Fix it by doing just that.

Reported-by: Robert O'Callahan <robert@ocallahan.org>
Signed-off-by: Yu-cheng Yu <yu-cheng.yu@intel.com>
Cc: <stable@vger.kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@suse.de>
Cc: David Hansen <dave.hansen@linux.intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ravi V. Shankar <ravi.v.shankar@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1479402695-6553-1-git-send-email-yu-cheng.yu@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-11-21 10:38:35 +01:00
Andy Lutomirski ed68d7e9b9 x86/boot: Fail the boot if !M486 and CPUID is missing
Linux will have all kinds of sporadic problems on systems that don't
have the CPUID instruction unless CONFIG_M486=y.  In particular,
sync_core() will explode.

I believe that these kernels had a better chance of working before
commit 05fb3c199b ("x86/boot: Initialize FPU and X86_FEATURE_ALWAYS
even if we don't have CPUID").  That commit inadvertently fixed a
serious bug: we used to fail to detect the FPU if CPUID wasn't
present.  Because we also used to forget to set X86_FEATURE_ALWAYS, we
end up with no cpu feature bits set at all.  This meant that
alternative patching didn't do anything and, if paravirt was disabled,
we could plausibly finish the entire boot process without calling
sync_core().

Rather than trying to work around these issues, just have the kernel
fail loudly if it's running on a CPUID-less 486, doesn't have CPUID,
and doesn't have CONFIG_M486 set.

Reported-by: Matthew Whitehead <tedheadster@gmail.com>
Signed-off-by: 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: 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/70eac6639f23df8be5fe03fa1984aedd5d40077a.1479598603.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-11-21 09:04:32 +01:00
Andy Lutomirski fc0e81b2be x86/traps: Ignore high word of regs->cs in early_fixup_exception()
On the 80486 DX, it seems that some exceptions may leave garbage in
the high bits of CS.  This causes sporadic failures in which
early_fixup_exception() refuses to fix up an exception.

As far as I can tell, this has been buggy for a long time, but the
problem seems to have been exacerbated by commits:

  1e02ce4ccc ("x86: Store a per-cpu shadow copy of CR4")
  e1bfc11c5a ("x86/init: Fix cr4_init_shadow() on CR4-less machines")

This appears to have broken for as long as we've had early
exception handling.

[ Note to stable maintainers: This patch is needed all the way back to 3.4,
  but it will only apply to 4.6 and up, as it depends on commit:

    0e861fbb5b ("x86/head: Move early exception panic code into early_fixup_exception()")

  If you want to backport to kernels before 4.6, please don't backport the
  prerequisites (there was a big chain of them that rewrote a lot of the
  early exception machinery); instead, ask me and I can send you a one-liner
  that will apply. ]

Reported-by: Matthew Whitehead <tedheadster@gmail.com>
Signed-off-by: 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: 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: stable@vger.kernel.org
Fixes: 4c5023a3fa ("x86-32: Handle exception table entries during early boot")
Link: http://lkml.kernel.org/r/cb32c69920e58a1a58e7b5cad975038a69c0ce7d.1479609510.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-11-21 08:06:54 +01:00
Linus Torvalds dce9ce3615 KVM fixes for v4.9-rc6
ARM:
  - Fix handling of the 32bit cycle counter
  - Fix cycle counter filtering
 
 x86:
  - Fix a race leading to double unregistering of user notifiers
  - Amend oversight in kvm_arch_set_irq that turned Hyper-V code dead
  - Use SRCU around kvm_lapic_set_vapic_addr
  - Avoid recursive flushing of asynchronous page faults
  - Do not rely on deferred update in KVM_GET_CLOCK, which fixes #GP
  - Let userspace know that KVM_GET_CLOCK is useful with master clock;
    4.9 changed the return value to better match the guest clock, but
    didn't provide means to let guests take advantage of it
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

Pull KVM fixes from Radim Krčmář:
 "ARM:
   - Fix handling of the 32bit cycle counter
   - Fix cycle counter filtering

  x86:
   - Fix a race leading to double unregistering of user notifiers
   - Amend oversight in kvm_arch_set_irq that turned Hyper-V code dead
   - Use SRCU around kvm_lapic_set_vapic_addr
   - Avoid recursive flushing of asynchronous page faults
   - Do not rely on deferred update in KVM_GET_CLOCK, which fixes #GP
   - Let userspace know that KVM_GET_CLOCK is useful with master clock;
     4.9 changed the return value to better match the guest clock, but
     didn't provide means to let guests take advantage of it"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
  kvm: x86: merge kvm_arch_set_irq and kvm_arch_set_irq_inatomic
  KVM: x86: fix missed SRCU usage in kvm_lapic_set_vapic_addr
  KVM: async_pf: avoid recursive flushing of work items
  kvm: kvmclock: let KVM_GET_CLOCK return whether the master clock is in use
  KVM: Disable irq while unregistering user notifier
  KVM: x86: do not go through vcpu in __get_kvmclock_ns
  KVM: arm64: Fix the issues when guest PMCCFILTR is configured
  arm64: KVM: pmu: Fix AArch32 cycle counter access
2016-11-19 13:31:40 -08:00
Paolo Bonzini a2b07739ff kvm: x86: merge kvm_arch_set_irq and kvm_arch_set_irq_inatomic
kvm_arch_set_irq is unused since commit b97e6de9c9.  Merge
its functionality with kvm_arch_set_irq_inatomic.

Reported-by: Jiang Biao <jiang.biao2@zte.com.cn>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
2016-11-19 19:04:19 +01:00
Paolo Bonzini 7301d6abae KVM: x86: fix missed SRCU usage in kvm_lapic_set_vapic_addr
Reported by syzkaller:

    [ INFO: suspicious RCU usage. ]
    4.9.0-rc4+ #47 Not tainted
    -------------------------------
    ./include/linux/kvm_host.h:536 suspicious rcu_dereference_check() usage!

    stack backtrace:
    CPU: 1 PID: 6679 Comm: syz-executor Not tainted 4.9.0-rc4+ #47
    Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
     ffff880039e2f6d0 ffffffff81c2e46b ffff88003e3a5b40 0000000000000000
     0000000000000001 ffffffff83215600 ffff880039e2f700 ffffffff81334ea9
     ffffc9000730b000 0000000000000004 ffff88003c4f8420 ffff88003d3f8000
    Call Trace:
     [<     inline     >] __dump_stack lib/dump_stack.c:15
     [<ffffffff81c2e46b>] dump_stack+0xb3/0x118 lib/dump_stack.c:51
     [<ffffffff81334ea9>] lockdep_rcu_suspicious+0x139/0x180 kernel/locking/lockdep.c:4445
     [<     inline     >] __kvm_memslots include/linux/kvm_host.h:534
     [<     inline     >] kvm_memslots include/linux/kvm_host.h:541
     [<ffffffff8105d6ae>] kvm_gfn_to_hva_cache_init+0xa1e/0xce0 virt/kvm/kvm_main.c:1941
     [<ffffffff8112685d>] kvm_lapic_set_vapic_addr+0xed/0x140 arch/x86/kvm/lapic.c:2217

Reported-by: Dmitry Vyukov <dvyukov@google.com>
Fixes: fda4e2e855
Cc: Andrew Honig <ahonig@google.com>
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
2016-11-19 19:04:18 +01:00
Paolo Bonzini e3fd9a93a1 kvm: kvmclock: let KVM_GET_CLOCK return whether the master clock is in use
Userspace can read the exact value of kvmclock by reading the TSC
and fetching the timekeeping parameters out of guest memory.  This
however is brittle and not necessary anymore with KVM 4.11.  Provide
a mechanism that lets userspace know if the new KVM_GET_CLOCK
semantics are in effect, and---since we are at it---if the clock
is stable across all VCPUs.

Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
2016-11-19 19:04:16 +01:00
Ignacio Alvarado 1650b4ebc9 KVM: Disable irq while unregistering user notifier
Function user_notifier_unregister should be called only once for each
registered user notifier.

Function kvm_arch_hardware_disable can be executed from an IPI context
which could cause a race condition with a VCPU returning to user mode
and attempting to unregister the notifier.

Signed-off-by: Ignacio Alvarado <ikalvarado@google.com>
Cc: stable@vger.kernel.org
Fixes: 18863bdd60 ("KVM: x86 shared msr infrastructure")
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
2016-11-19 19:04:04 +01:00
Paolo Bonzini 8b95344064 KVM: x86: do not go through vcpu in __get_kvmclock_ns
Going through the first VCPU is wrong if you follow a KVM_SET_CLOCK with
a KVM_GET_CLOCK immediately after, without letting the VCPU run and
call kvm_guest_time_update.

To fix this, compute the kvmclock value ourselves, using the master
clock (tsc, nsec) pair as the base and the host CPU frequency as
the scale.

Reported-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
2016-11-19 18:03:03 +01:00
Linus Torvalds 04e36857d6 Merge branch 'rc-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild
Pull kbuild fixes from Michal Marek:
 "Here are some regression fixes for kbuild:

   - modversion support for exported asm symbols (Nick Piggin). The
     affected architectures need separate patches adding
     asm-prototypes.h.

   - fix rebuilds of lib-ksyms.o (Nick Piggin)

   - -fno-PIE builds (Sebastian Siewior and Borislav Petkov). This is
     not a kernel regression, but one of the Debian gcc package.
     Nevertheless, it's quite annoying, so I think it should go into
     mainline and stable now"

* 'rc-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild:
  kbuild: Steal gcc's pie from the very beginning
  kbuild: be more careful about matching preprocessed asm ___EXPORT_SYMBOL
  x86/kexec: add -fno-PIE
  scripts/has-stack-protector: add -fno-PIE
  kbuild: add -fno-PIE
  kbuild: modversions for EXPORT_SYMBOL() for asm
  kbuild: prevent lib-ksyms.o rebuilds
2016-11-18 16:45:21 -08:00
Janakarajan Natarajan e40ed1542d perf/x86: Add perf support for AMD family-17h processors
This patch enables perf core PMU support for the new AMD family-17h processors.

In family-17h, there is no PMC-event constraint. All events, irrespective of
the type, can be measured using any of the six generic performance counters.

Signed-off-by: Janakarajan Natarajan <Janakarajan.Natarajan@amd.com>
Acked-by: Borislav Petkov <bp@suse.de>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Link: http://lkml.kernel.org/r/1479399306-13375-1-git-send-email-Janakarajan.Natarajan@amd.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-11-18 09:45:57 +01:00
Josh Poimboeuf 91e08ab0c8 x86/dumpstack: Prevent KASAN false positive warnings
The oops stack dump code scans the entire stack, which can cause KASAN
"stack-out-of-bounds" false positive warnings.  Tell KASAN to ignore it.

Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@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: Stephane Eranian <eranian@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: davej@codemonkey.org.uk
Cc: dvyukov@google.com
Link: http://lkml.kernel.org/r/5f6e80c4b0c7f7f0b6211900847a247cdaad753c.1479398226.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-11-18 09:38:00 +01:00
Josh Poimboeuf c2d75e03d6 x86/unwind: Prevent KASAN false positive warnings in guess unwinder
The guess unwinder scans the entire stack, which can cause KASAN
"stack-out-of-bounds" false positive warnings.  Tell KASAN to ignore it.

Reported-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@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: Stephane Eranian <eranian@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: davej@codemonkey.org.uk
Cc: dvyukov@google.com
Link: http://lkml.kernel.org/r/61939c0b2b2d63ce97ba59cba3b00fd47c2962cf.1479398226.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-11-18 09:38:00 +01:00
Arnd Bergmann 553bbc11aa x86/boot: Avoid warning for zero-filling .bss
The latest binutils are warning about a .fill directive with an explicit
value in a .bss section:

  arch/x86/kernel/head_32.S: Assembler messages:
  arch/x86/kernel/head_32.S:677: Warning: ignoring fill value in section `.bss..page_aligned'
  arch/x86/kernel/head_32.S:679: Warning: ignoring fill value in section `.bss..page_aligned'

This comes from the 'ENTRY()' macro padding the space between the symbols
with 'nop' via:

  .align 4,0x90

Open-coding the .globl directive without the padding avoids that warning,
as all the symbols are already page aligned.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
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: 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/20161116141726.2013389-1-arnd@arndb.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-11-17 07:34:58 +01:00
Kan Liang c499336cea perf/x86/uncore: Fix crash by removing bogus event_list[] handling for SNB client uncore IMC
Vince Weaver reported the following bug when KASAN is enabled:

 [  205.748005] BUG: KASAN: slab-out-of-bounds in snb_uncore_imc_event_del+0x6c/0xa0 at addr ffff8800caa43768
 [  205.758324] Read of size 8 by task perf_fuzzer/6618

It's caused by accessing box->event_list.

For client IMC, there are no generic counters. It defines its own fixed
free running counters. So event_list and n_events are unused.

They can be removed safely, which fixes the bug.

( There's still the separate question of how uninitialized state snuck into
  this data structure - but that's a separate fix. )

Reported-by: Vince Weaver <vincent.weaver@maine.edu>
Tested-by: Vince Weaver <vincent.weaver@maine.edu>
Signed-off-by: Kan Liang <kan.liang@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: acme@kernel.org
Cc: davej@codemonkey.org.uk
Cc: dvyukov@google.com
Cc: eranian@gmail.com
Link: http://lkml.kernel.org/r/1479235210-29090-1-git-send-email-kan.liang@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-11-16 09:46:35 +01:00
David Herrmann f96acec8c8 x86/sysfb: Fix lfb_size calculation
The screen_info.lfb_size field is shifted by 16 bits *only* in case of
VBE. This has historical reasons since VBE advertised it similarly.
However, in case of EFI framebuffers, the size is no longer shifted. Fix
the x86 simple-framebuffer setup code to use the correct size in the
non-VBE case.

While at it, avoid variable abbreviations and rename 'len' to 'length',
and use the correct types matching the screen_info definition.

Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matt Fleming <matt.fleming@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Tom Gundersen <teg@jklm.no>
Link: http://lkml.kernel.org/r/20161115120158.15388-3-dh.herrmann@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-11-16 09:38:23 +01:00
David Herrmann 9164b4ceb7 x86/sysfb: Add support for 64bit EFI lfb_base
The screen_info object was extended to support 64-bit lfb_base addresses
in:

  ae2ee627dc ("efifb: Add support for 64-bit frame buffer addresses")

However, the x86 simple-framebuffer setup code never made use of it. Fix
it to properly assemble and verify the lfb_base before advertising
simple-framebuffer devices.

In particular, this means if VIDEO_CAPABILITY_64BIT_BASE is set, the
screen_info->ext_lfb_base field will contain the upper 32bit of the
actual lfb_base. Make sure the address is not 0 (i.e., unset), as well as
does not overflow the physical address type.

Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matt Fleming <matt.fleming@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Tom Gundersen <teg@jklm.no>
Link: http://lkml.kernel.org/r/20161115120158.15388-2-dh.herrmann@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-11-16 09:38:22 +01:00
Linus Torvalds 8528d66248 Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 fixes from Ingo Molnar:
 "Misc fixes:

   - fix an Intel/MID boot crash/hang bug

   - fix a cache topology mis-parsing bug on certain AMD CPUs

   - fix a virtualization firmware bug by adding a check+quirk
     workaround on the kernel side"

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/cpu: Deal with broken firmware (VMWare/XEN)
  x86/cpu/AMD: Fix cpu_llc_id for AMD Fam17h systems
  x86/platform/intel-mid: Retrofit pci_platform_pm_ops ->get_state hook
2016-11-14 08:39:56 -08:00
Linus Torvalds 5ad62a9e5c Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull perf fixes from Ingo Molnar:
 "An uncore PMU driver hardware enablement change for Intel SkyLake
  uncore PMUs (Skylake Y, U, H and S platforms), plus a number of
  tooling fixes for the histogram handling/displaying code"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf/x86/intel/uncore: Add more Intel uncore IMC PCI IDs for SkyLake
  perf hists: Fix column length on --hierarchy
  perf hists browser: Fix column indentation on --hierarchy
  perf hists browser: Show folded sign properly on --hierarchy
  perf hists browser: Fix indentation of folded sign on --hierarchy
  perf hist browser: Fix hierarchy column counts
2016-11-14 08:30:06 -08:00
Matt Fleming f6697df36b x86/efi: Prevent mixed mode boot corruption with CONFIG_VMAP_STACK=y
Booting an EFI mixed mode kernel has been crashing since commit:

  e37e43a497 ("x86/mm/64: Enable vmapped stacks (CONFIG_HAVE_ARCH_VMAP_STACK=y)")

The user-visible effect in my test setup was the kernel being unable
to find the root file system ramdisk. This was likely caused by silent
memory or page table corruption.

Enabling CONFIG_DEBUG_VIRTUAL=y immediately flagged the thunking code as
abusing virt_to_phys() because it was passing addresses that were not
part of the kernel direct mapping.

Use the slow version instead, which correctly handles all memory
regions by performing a page table walk.

Suggested-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.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: 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: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/20161112210424.5157-3-matt@codeblueprint.co.uk
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-11-13 08:26:40 +01:00
Borislav Petkov 02e56902e4 x86/efi: Fix EFI memmap pointer size warning
Fix this when building on 32-bit:

  arch/x86/platform/efi/efi.c: In function ‘__efi_enter_virtual_mode’:
  arch/x86/platform/efi/efi.c:911:5: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]
       (efi_memory_desc_t *)pa);
       ^
  arch/x86/platform/efi/efi.c:918:5: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]
       (efi_memory_desc_t *)pa);
       ^

The @pa local variable is declared as phys_addr_t and that is a u64 when
CONFIG_PHYS_ADDR_T_64BIT=y. (The last is enabled on 32-bit on a PAE
build.)

However, its value comes from __pa() which is basically doing pointer
arithmetic and checking, and returns unsigned long as it is the native
pointer width.

So let's use an unsigned long too. It should be fine to do so because
the later users cast it to a pointer too.

Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.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: 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: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/20161112210424.5157-2-matt@codeblueprint.co.uk
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-11-13 08:26:40 +01:00
Arnd Bergmann beae2c9eb5 crypto: aesni: shut up -Wmaybe-uninitialized warning
The rfc4106 encrypy/decrypt helper functions cause an annoying
false-positive warning in allmodconfig if we turn on
-Wmaybe-uninitialized warnings again:

  arch/x86/crypto/aesni-intel_glue.c: In function ‘helper_rfc4106_decrypt’:
  include/linux/scatterlist.h:67:31: warning: ‘dst_sg_walk.sg’ may be used uninitialized in this function [-Wmaybe-uninitialized]

The problem seems to be that the compiler doesn't track the state of the
'one_entry_in_sg' variable across the kernel_fpu_begin/kernel_fpu_end
section.

This takes the easy way out by adding a bogus initialization, which
should be harmless enough to get the patch into v4.9 so we can turn on
this warning again by default without producing useless output.  A
follow-up patch for v4.10 rearranges the code to make the warning go
away.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-11-11 08:45:08 -08:00
Arnd Bergmann 3a6d867612 x86: apm: avoid uninitialized data
apm_bios_call() can fail, and return a status in its argument structure.
If that status however is zero during a call from
apm_get_power_status(), we end up using data that may have never been
set, as reported by "gcc -Wmaybe-uninitialized":

  arch/x86/kernel/apm_32.c: In function ‘apm’:
  arch/x86/kernel/apm_32.c:1729:17: error: ‘bx’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
  arch/x86/kernel/apm_32.c:1835:5: error: ‘cx’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
  arch/x86/kernel/apm_32.c:1730:17: note: ‘cx’ was declared here
  arch/x86/kernel/apm_32.c:1842:27: error: ‘dx’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
  arch/x86/kernel/apm_32.c:1731:17: note: ‘dx’ was declared here

This changes the function to return "APM_NO_ERROR" here, which makes the
code more robust to broken BIOS versions, and avoids the warning.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Jiri Kosina <jkosina@suse.cz>
Reviewed-by: Luis R. Rodriguez <mcgrof@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-11-11 08:45:08 -08:00
Kan Liang d786810b2f perf/x86/intel/uncore: Add more Intel uncore IMC PCI IDs for SkyLake
Several uncore IMC PCI IDs are missed for Intel SkyLake.

Add the PCI IDs for SkyLake Y, U, H and S platforms.
Rename the ID macros for 0x191f and 0x190c.

The corresponding bug:

  https://bugzilla.kernel.org/show_bug.cgi?id=187301

The related datasheets are also attached in the bug entry for permanent reference.

Reported-by: Ben Widawsky <benjamin.widawsky@intel.com>
Tested-by: Ben Widawsky <benjamin.widawsky@intel.com>
Signed-off-by: Kan Liang <kan.liang@intel.com>
Reviewed-by: Ben Widawsky <benjamin.widawsky@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Link: http://lkml.kernel.org/r/1478631281-5061-1-git-send-email-kan.liang@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-11-11 08:30:22 +01:00
Sebastian Andrzej Siewior 90944e40ba x86/kexec: add -fno-PIE
If the gcc is configured to do -fPIE by default then the build aborts
later with:
| Unsupported relocation type: unknown type rel type name (29)

Tagging it stable so it is possible to compile recent stable kernels as
well.

Cc: stable@vger.kernel.org
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Michal Marek <mmarek@suse.com>
2016-11-09 22:28:09 +01:00
Thomas Gleixner d49597fd3b x86/cpu: Deal with broken firmware (VMWare/XEN)
Both ACPI and MP specifications require that the APIC id in the respective
tables must be the same as the APIC id in CPUID.

The kernel retrieves the physical package id from the APIC id during the
ACPI/MP table scan and builds the physical to logical package map. The
physical package id which is used after a CPU comes up is retrieved from
CPUID. So we rely on ACPI/MP tables and CPUID agreeing in that respect.

There exist VMware and XEN implementations which violate the spec. As a
result the physical to logical package map, which relies on the ACPI/MP
tables does not work on those systems, because the CPUID initialized
physical package id does not match the firmware id. This causes system
crashes and malfunction due to invalid package mappings.

The only way to cure this is to sanitize the physical package id after the
CPUID enumeration and yell when the APIC ids are different. Fix up the
initial APIC id, which is fine as it is only used printout purposes.

If the physical package IDs differ yell and use the package information
from the ACPI/MP tables so the existing logical package map just works.

Chas provided the resulting dmesg output for his affected 4 virtual
sockets, 1 core per socket VM:

[Firmware Bug]: CPU1: APIC id mismatch. Firmware: 1 CPUID: 2
[Firmware Bug]: CPU1: Using firmware package id 1 instead of 2
....

Reported-and-tested-by: "Charles (Chas) Williams" <ciwillia@brocade.com>,
Reported-by: M. Vefa Bicakci <m.v.b@runbox.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Alok Kataria <akataria@vmware.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: #4.6+ <stable@vger,kernel.org>
Link: http://lkml.kernel.org/r/alpine.DEB.2.20.1611091613540.3501@nanos
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-11-09 21:05:01 +01:00
Yazen Ghannam b0b6e86846 x86/cpu/AMD: Fix cpu_llc_id for AMD Fam17h systems
cpu_llc_id (Last Level Cache ID) derivation on AMD Fam17h has an
underflow bug when extracting the socket_id value. It starts from 0
so subtracting 1 from it will result in an invalid value. This breaks
scheduling topology later on since the cpu_llc_id will be incorrect.

For example, the the cpu_llc_id of the *other* CPU in the loops in
set_cpu_sibling_map() underflows and we're generating the funniest
thread_siblings masks and then when I run 8 threads of nbench, they get
spread around the LLC domains in a very strange pattern which doesn't
give you the normal scheduling spread one would expect for performance.

Other things like EDAC use cpu_llc_id so they will be b0rked too.

So, the APIC ID is preset in APICx020 for bits 3 and above: they contain
the core complex, node and socket IDs.

The LLC is at the core complex level so we can find a unique cpu_llc_id
by right shifting the APICID by 3 because then the least significant bit
will be the Core Complex ID.

Tested-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Yazen Ghannam <Yazen.Ghannam@amd.com>
[ Cleaned up and extended the commit message. ]
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: <stable@vger.kernel.org> # v4.4..
Cc: Aravind Gopalakrishnan <aravindksg.lkml@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Fixes: 3849e91f57 ("x86/AMD: Fix last level cache topology for AMD Fam17h systems")
Link: http://lkml.kernel.org/r/20161108083506.rvqb5h4chrcptj7d@pd.tnic
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-11-09 17:06:08 +01:00