Pull x86 fixes from Thomas Gleixner:
 "A set of fixes for x86:

   - Fix the bogus detection of 32bit user mode for uretprobes which
     caused corruption of the user return address resulting in
     application crashes. In the uprobes handler in_ia32_syscall() is
     obviously always returning false on a 64bit kernel. Use
     user_64bit_mode() instead which works correctly.

   - Prevent large page splitting when ftrace flips RW/RO on the kernel
     text which caused iTLB performance issues. Ftrace wants to be
     converted to text_poke() which avoids the problem, but for now
     allow large page preservation in the static protections check when
     the change request spawns a full large page.

   - Prevent arch_dynirq_lower_bound() from returning 0 when the IOAPIC
     is configured via device tree. In the device tree case the GSI 1:1
     mapping is meaningless therefore the lower bound which protects the
     GSI range on ACPI machines is irrelevant. Return the lower bound
     which the core hands to the function instead of blindly returning 0
     which causes the core to allocate the invalid virtual interupt
     number 0 which in turn prevents all drivers from allocating and
     requesting an interrupt.

   - Remove the bogus initialization of LDR and DFR in the 32bit bigsmp
     APIC driver. That uses physical destination mode where LDR/DFR are
     ignored, but the initialization and the missing clear of LDR caused
     the APIC to be left in a inconsistent state on kexec/reboot.

   - Clear LDR when clearing the APIC registers so the APIC is in a well
     defined state.

   - Initialize variables proper in the find_trampoline_placement()
     code.

   - Silence GCC( build warning for the real mode part of the build"

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/mm/cpa: Prevent large page split when ftrace flips RW on kernel text
  x86/build: Add -Wnoaddress-of-packed-member to REALMODE_CFLAGS, to silence GCC9 build warning
  x86/boot/compressed/64: Fix missing initialization in find_trampoline_placement()
  x86/apic: Include the LDR when clearing out APIC registers
  x86/apic: Do not initialize LDR and DFR for bigsmp
  uprobes/x86: Fix detection of 32-bit user mode
  x86/apic: Fix arch_dynirq_lower_bound() bug for DT enabled machines

Pull perf fixes from Thomas Gleixner:
 "Two fixes for perf x86 hardware implementations:

   - Restrict the period on Nehalem machines to prevent perf from
     hogging the CPU

   - Prevent the AMD IBS driver from overwriting the hardwre controlled
     and pre-seeded reserved bits (0-6) in the count register which
     caused a sample bias for dispatched micro-ops"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf/x86/amd/ibs: Fix sample bias for dispatched micro-ops
  perf/x86/intel: Restrict period on Nehalem

Pull tracing fixes from Steven Rostedt:
 "Small fixes and minor cleanups for tracing:

   - Make exported ftrace function not static

   - Fix NULL pointer dereference in reading probes as they are created

   - Fix NULL pointer dereference in k/uprobe clean up path

   - Various documentation fixes"

* tag 'trace-v5.3-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  tracing: Correct kdoc formats
  ftrace/x86: Remove mcount() declaration
  tracing/probe: Fix null pointer dereference
  tracing: Make exported ftrace_set_clr_event non-static
  ftrace: Check for successful allocation of hash
  ftrace: Check for empty hash and comment the race with registering probes
  ftrace: Fix NULL pointer dereference in t_probe_next()

Pull RISC-V fix from Paul Walmsley:
 "One significant fix for 32-bit RISC-V systems:

  Fix the RV32 memory map to prevent userspace from corrupting the
  FIXMAP area. Without this patch, the system can crash very early
  during the boot"

* tag 'riscv/for-v5.3-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux:
  RISC-V: Fix FIXMAP area corruption on RV32 systems

Pull KVM fixes from Radim Krčmář:
 "PPC:
   - Fix bug which could leave locks held in the host on return to a
     guest.

  x86:
   - Prevent infinitely looping emulation of a failing syscall while
     single stepping.

   - Do not crash the host when nesting is disabled"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
  KVM: x86: Don't update RIP or do single-step on faulting emulation
  KVM: x86: hyper-v: don't crash on KVM_GET_SUPPORTED_HV_CPUID when kvm_intel.nested is disabled
  KVM: PPC: Book3S: Fix incorrect guest-to-user-translation error handling

Commit 562e14f72292 ("ftrace/x86: Remove mcount support") removed the
support for using mcount, so we could remove the mcount() declaration
to clean up.

Link: http://lkml.kernel.org/r/20190826170150.10f101ba@xhacker.debian

Signed-off-by: Jisheng Zhang <Jisheng.Zhang@synaptics.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

Pull ARM fixes from Russell King:
 "Three fixes for ARM this time around:

   - A fix for update_sections_early() to cope with NULL ->mm pointers.

   - A correction to the backtrace code to allow proper backtraces.

   - Reinforcement of pfn_valid() with PFNs >= 4GiB"

* tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm:
  ARM: 8901/1: add a criteria for pfn_valid of arm
  ARM: 8897/1: check stmfd instruction using right shift
  ARM: 8874/1: mm: only adjust sections of valid mm structures

Pull ARM SoC fixes from Arnd Bergmann:
 "The majority of the fixes this time are for OMAP hardware, here is a
  breakdown of the significant changes:

  Various device tree bug fixes:
   - TI am57xx boards need a voltage level fix to avoid damaging SD
     cards
   - vf610-bk4 fails to detect its flash due to an incorrect description
   - meson-g12a USB phy configuration fails
   - meson-g12b reboot should not power off the SD card
   - Some corrections for apparently harmless differences from the
     documentation.

  Regression fixes:
   - ams-delta FIQ interrupts broke in 5.3
   - TI am3/am4 mmc controllers broke in 5.2

  The logic_pio driver (used on some Huawei ARM servers) got a few bug
  fixes for reliability.

  And a couple of compile-time warning fixes"

* tag 'armsoc-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/soc/soc: (26 commits)
  soc: ixp4xx: Protect IXP4xx SoC drivers by ARCH_IXP4XX || COMPILE_TEST
  soc: ti: pm33xx: Make two symbols static
  soc: ti: pm33xx: Fix static checker warnings
  ARM: OMAP: dma: Mark expected switch fall-throughs
  ARM: dts: Fix incomplete dts data for am3 and am4 mmc
  bus: ti-sysc: Simplify cleanup upon failures in sysc_probe()
  ARM: OMAP1: ams-delta-fiq: Fix missing irq_ack
  ARM: dts: dra74x: Fix iodelay configuration for mmc3
  ARM: dts: am335x: Fix UARTs length
  ARM: OMAP2+: Fix omap4 errata warning on other SoCs
  bus: hisi_lpc: Add .remove method to avoid driver unbind crash
  bus: hisi_lpc: Unregister logical PIO range to avoid potential use-after-free
  lib: logic_pio: Add logic_pio_unregister_range()
  lib: logic_pio: Avoid possible overlap for unregistering regions
  lib: logic_pio: Fix RCU usage
  arm64: dts: amlogic: odroid-n2: keep SD card regulator always on
  arm64: dts: meson-g12a-sei510: enable IR controller
  arm64: dts: meson-g12a: add missing dwc2 phy-names
  ARM: dts: vf610-bk4: Fix qspi node description
  ARM: dts: Fix incorrect dcan register mapping for am3, am4 and dra7
  ...

When counting dispatched micro-ops with cnt_ctl=1, in order to prevent
sample bias, IBS hardware preloads the least significant 7 bits of
current count (IbsOpCurCnt) with random values, such that, after the
interrupt is handled and counting resumes, the next sample taken
will be slightly perturbed.

The current count bitfield is in the IBS execution control h/w register,
alongside the maximum count field.

Currently, the IBS driver writes that register with the maximum count,
leaving zeroes to fill the current count field, thereby overwriting
the random bits the hardware preloaded for itself.

Fix the driver to actually retain and carry those random bits from the
read of the IBS control register, through to its write, instead of
overwriting the lower current count bits with zeroes.

Tested with:

perf record -c 100001 -e ibs_op/cnt_ctl=1/pp -a -C 0 taskset -c 0 <workload>

'perf annotate' output before:

 15.70  65:   addsd     %xmm0,%xmm1
 17.30        add       $0x1,%rax
 15.88        cmp       %rdx,%rax
              je        82
 17.32  72:   test      $0x1,%al
              jne       7c
  7.52        movapd    %xmm1,%xmm0
  5.90        jmp       65
  8.23  7c:   sqrtsd    %xmm1,%xmm0
 12.15        jmp       65

'perf annotate' output after:

 16.63  65:   addsd     %xmm0,%xmm1
 16.82        add       $0x1,%rax
 16.81        cmp       %rdx,%rax
              je        82
 16.69  72:   test      $0x1,%al
              jne       7c
  8.30        movapd    %xmm1,%xmm0
  8.13        jmp       65
  8.24  7c:   sqrtsd    %xmm1,%xmm0
  8.39        jmp       65

Tested on Family 15h and 17h machines.

Machines prior to family 10h Rev. C don't have the RDWROPCNT capability,
and have the IbsOpCurCnt bitfield reserved, so this patch shouldn't
affect their operation.

It is unknown why commit db98c5faf8cb ("perf/x86: Implement 64-bit
counter support for IBS") ignored the lower 4 bits of the IbsOpCurCnt
field; the number of preloaded random bits has always been 7, AFAICT.

Signed-off-by: Kim Phillips <kim.phillips@amd.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: "Arnaldo Carvalho de Melo" <acme@kernel.org>
Cc: <x86@kernel.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "Borislav Petkov" <bp@alien8.de>
Cc: Stephane Eranian <eranian@google.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: "Namhyung Kim" <namhyung@kernel.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Link: https://lkml.kernel.org/r/20190826195730.30614-1-kim.phillips@amd.com

We see our Nehalem machines reporting 'perfevents: irq loop stuck!' in
some cases when using perf:

perfevents: irq loop stuck!
WARNING: CPU: 0 PID: 3485 at arch/x86/events/intel/core.c:2282 intel_pmu_handle_irq+0x37b/0x530
...
RIP: 0010:intel_pmu_handle_irq+0x37b/0x530
...
Call Trace:
<NMI>
? perf_event_nmi_handler+0x2e/0x50
? intel_pmu_save_and_restart+0x50/0x50
perf_event_nmi_handler+0x2e/0x50
nmi_handle+0x6e/0x120
default_do_nmi+0x3e/0x100
do_nmi+0x102/0x160
end_repeat_nmi+0x16/0x50
...
? native_write_msr+0x6/0x20
? native_write_msr+0x6/0x20
</NMI>
intel_pmu_enable_event+0x1ce/0x1f0
x86_pmu_start+0x78/0xa0
x86_pmu_enable+0x252/0x310
__perf_event_task_sched_in+0x181/0x190
? __switch_to_asm+0x41/0x70
? __switch_to_asm+0x35/0x70
? __switch_to_asm+0x41/0x70
? __switch_to_asm+0x35/0x70
finish_task_switch+0x158/0x260
__schedule+0x2f6/0x840
? hrtimer_start_range_ns+0x153/0x210
schedule+0x32/0x80
schedule_hrtimeout_range_clock+0x8a/0x100
? hrtimer_init+0x120/0x120
ep_poll+0x2f7/0x3a0
? wake_up_q+0x60/0x60
do_epoll_wait+0xa9/0xc0
__x64_sys_epoll_wait+0x1a/0x20
do_syscall_64+0x4e/0x110
entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x7fdeb1e96c03
...
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: acme@kernel.org
Cc: Josh Hunt <johunt@akamai.com>
Cc: bpuranda@akamai.com
Cc: mingo@redhat.com
Cc: jolsa@redhat.com
Cc: tglx@linutronix.de
Cc: namhyung@kernel.org
Cc: alexander.shishkin@linux.intel.com
Link: https://lkml.kernel.org/r/1566256411-18820-1-git-send-email-johunt@akamai.com