Add pca9450 pmic driver.
Signed-off-by: NRobin Gong <yibin.gong@nxp.com>
Signed-off-by: NShawn Guo <shawnguo@kernel.org>

Since commit 84af7a61 ("checkpatch: kconfig: prefer 'help' over
'---help---'"), the number of '---help---' has been gradually
decreasing, but there are still more than 2400 instances.

This commit finishes the conversion. While I touched the lines,
I also fixed the indentation.

There are a variety of indentation styles found.

  a) 4 spaces + '---help---'
  b) 7 spaces + '---help---'
  c) 8 spaces + '---help---'
  d) 1 space + 1 tab + '---help---'
  e) 1 tab + '---help---'    (correct indentation)
  f) 1 tab + 1 space + '---help---'
  g) 1 tab + 2 spaces + '---help---'

In order to convert all of them to 1 tab + 'help', I ran the
following commend:

  $ find . -name 'Kconfig*' | xargs sed -i 's/^[[:space:]]*---help---/\thelp/'
Signed-off-by: NMasahiro Yamada <masahiroy@kernel.org>

EFI on ARM only supports short descriptors, and given that it mandates
that the MMU and caches are on, it is implied that booting in HYP mode
is not supported.

However, implementations of EFI exist (i.e., U-Boot) that ignore this
requirement, which is not entirely unreasonable, given that it makes
HYP mode inaccessible to the operating system.

So let's make sure that we can deal with this condition gracefully.
We already tolerate booting the EFI stub with the caches off (even
though this violates the EFI spec as well), and so we should deal
with HYP mode boot with MMU and caches either on or off.

- When the MMU and caches are on, we can ignore the HYP stub altogether,
  since we can carry on executing at HYP. We do need to ensure that we
  disable the MMU at HYP before entering the kernel proper.

- When the MMU and caches are off, we have to drop to SVC mode so that
  we can set up the page tables using short descriptors. In this case,
  we need to install the HYP stub as usual, so that we can return to HYP
  mode before handing over to the kernel proper.
Tested-by: NHeinrich Schuchardt <xypron.glpk@gmx.de>
Signed-off-by: NArd Biesheuvel <ardb@kernel.org>
Signed-off-by: NRussell King <rmk+kernel@armlinux.org.uk>

ZBOOT_ROM_TEXT and ZBOOT_ROM_BSS are defined as 'hex' but had a default
of "0". Kconfig will helpfully expand a text entry of 0 to 0x0 but
because this is not the same as the default value it was treated as
being explicitly set when running 'make savedefconfig' so most arm
defconfigs have CONFIG_ZBOOT_ROM_TEXT=0x0 and CONFIG_ZBOOT_ROM_BSS=0x0.

Change the default to 0x0 which will mean next time the defconfigs are
re-generated the spurious config entries will be removed.
Signed-off-by: NChris Packham <chris.packham@alliedtelesis.co.nz>
Signed-off-by: NRussell King <rmk+kernel@armlinux.org.uk>

The patch introducing the struct was probably never compile tested,
because it sets a handler with a wrong function signature. Wrap the
handler into a functions with the correct signature to fix the build.

Fixes: 0f1c9688 ("tty/sysrq: alpha: export and use __sysrq_get_key_op()")
Cc: Emil Velikov <emil.l.velikov@gmail.com>
Reviewed-by: NGuenter Roeck <linux@roeck-us.net>
Tested-by: NGuenter Roeck <linux@roeck-us.net>
Signed-off-by: NJoerg Roedel <jroedel@suse.de>
Signed-off-by: NMatt Turner <mattst88@gmail.com>

Signed-off-by: NMatt Turner <mattst88@gmail.com>

Replace sg++ with sg = sg_next(sg).
Signed-off-by: NXu Wang <vulab@iscas.ac.cn>
Signed-off-by: NMatt Turner <mattst88@gmail.com>

The commits cd0e00c1 and 92d7223a broke boot on the Alpha Avanti
platform. The patches move memory barriers after a write before the write.
The result is that if there's iowrite followed by ioread, there is no
barrier between them.

The Alpha architecture allows reordering of the accesses to the I/O space,
and the missing barrier between write and read causes hang with serial
port and real time clock.

This patch makes barriers confiorm to the specification.

1. We add mb() before readX_relaxed and writeX_relaxed -
   memory-barriers.txt claims that these functions must be ordered w.r.t.
   each other. Alpha doesn't order them, so we need an explicit barrier.
2. We add mb() before reads from the I/O space - so that if there's a
   write followed by a read, there should be a barrier between them.
Signed-off-by: NMikulas Patocka <mpatocka@redhat.com>
Fixes: cd0e00c1 ("alpha: io: reorder barriers to guarantee writeX() and iowriteX() ordering")
Fixes: 92d7223a ("alpha: io: reorder barriers to guarantee writeX() and iowriteX() ordering #2")
Cc: stable@vger.kernel.org      # v4.17+
Acked-by: NIvan Kokshaysky <ink@jurassic.park.msu.ru>
Reviewed-by: NMaciej W. Rozycki <macro@linux-mips.org>
Signed-off-by: NMatt Turner <mattst88@gmail.com>

Fix the following coccicheck warning:

arch/alpha/kernel/sys_eiger.c:179:2-3: Unneeded semicolon
Signed-off-by: NJason Yan <yanaijie@huawei.com>
Signed-off-by: NMatt Turner <mattst88@gmail.com>

Fix the following coccicheck warning:

arch/alpha/kernel/osf_sys.c:680:2-3: Unneeded semicolon
Signed-off-by: NJason Yan <yanaijie@huawei.com>
Signed-off-by: NMatt Turner <mattst88@gmail.com>

In commit b6b27355
("tracing: Use str_has_prefix() instead of using fixed sizes")
the newly introduced str_has_prefix() was used
to replace error-prone strncmp(str, const, len).
Here fix codes with the same pattern.
Signed-off-by: NChuhong Yuan <hslester96@gmail.com>
Signed-off-by: NMatt Turner <mattst88@gmail.com>

Alpha incorrectly reports "0070-0080 : rtc" in /proc/ioports.
Fix this, so that it is "0070-007f".
Signed-off-by: NMikulas Patocka <mpatocka@redhat.com>
Signed-off-by: NMatt Turner <mattst88@gmail.com>

Formatting of Kconfig files doesn't look so pretty, so let the
Great White Handkerchief come around and clean it up.
Signed-off-by: NEnrico Weigelt, metux IT consult <info@metux.net>
Signed-off-by: NMatt Turner <mattst88@gmail.com>

The idea of conditionally calling into rcu_irq_enter() only when RCU is
not watching turned out to be not completely thought through.

Paul noticed occasional premature end of grace periods in RCU torture
testing. Bisection led to the commit which made the invocation of
rcu_irq_enter() conditional on !rcu_is_watching().

It turned out that this conditional breaks RCU assumptions about the idle
task when the scheduler tick happens to be a nested interrupt. Nested
interrupts can happen when the first interrupt invokes softirq processing
on return which enables interrupts.

If that nested tick interrupt does not invoke rcu_irq_enter() then the
RCU's irq-nesting checks will believe that this interrupt came directly
from idle, which will cause RCU to report a quiescent state.  Because this
interrupt instead came from a softirq handler which might have been
executing an RCU read-side critical section, this can cause the grace
period to end prematurely.

Change the condition from !rcu_is_watching() to is_idle_task(current) which
enforces that interrupts in the idle task unconditionally invoke
rcu_irq_enter() independent of the RCU state.

This is also correct vs. user mode entries in NOHZ full scenarios because
user mode entries bring RCU out of EQS and force the RCU irq nesting state
accounting to nested. As only the first interrupt can enter from user mode
a nested tick interrupt will enter from kernel mode and as the nesting
state accounting is forced to nesting it will not do anything stupid even
if rcu_irq_enter() has not been invoked.

Fixes: 3eeec385 ("x86/entry: Provide idtentry_entry/exit_cond_rcu()")
Reported-by: N"Paul E. McKenney" <paulmck@kernel.org>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Tested-by: N"Paul E. McKenney" <paulmck@kernel.org>
Reviewed-by: N"Paul E. McKenney" <paulmck@kernel.org>
Acked-by: NAndy Lutomirski <luto@kernel.org>
Acked-by: NFrederic Weisbecker <frederic@kernel.org>
Link: https://lkml.kernel.org/r/87wo4cxubv.fsf@nanos.tec.linutronix.de

For no reason other than beginning brainmelt, IDTENTRY_NMI was mapped to
IDTENTRY_IST.

This is not a problem on 64bit because the IST default entry point maps to
IDTENTRY_RAW which does not any entry handling. The surplus function
declaration for the noist C entry point is unused and as there is no ASM
code emitted for NMI this went unnoticed.

On 32bit IDTENTRY_IST maps to a regular IDTENTRY which does the normal
entry handling. That is clearly the wrong thing to do for NMI.

Map it to IDTENTRY_RAW to unbreak it. The IDTENTRY_NMI mapping needs to
stay to avoid emitting ASM code.

Fixes: 6271fef0 ("x86/entry: Convert NMI to IDTENTRY_NMI")
Reported-by: NNaresh Kamboju <naresh.kamboju@linaro.org>
Debugged-by: NAndy Lutomirski <luto@kernel.org>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/CA+G9fYvF3cyrY+-iw_SZtpN-i2qA2BruHg4M=QYECU2-dNdsMw@mail.gmail.com

BUG/WARN are cleverly optimized using UD2 to handle the BUG/WARN out of
line in an exception fixup.

But if BUG or WARN is issued in a funny RCU context, then the
idtentry_enter...() path might helpfully WARN that the RCU context is
invalid, which results in infinite recursion.

Split the BUG/WARN handling into an nmi_enter()/nmi_exit() path in
exc_invalid_op() to increase the chance to survive the experience.

[ tglx: Make the declaration match the implementation ]
Signed-off-by: NAndy Lutomirski <luto@kernel.org>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/f8fe40e0088749734b4435b554f73eee53dcf7a8.1591932307.git.luto@kernel.org

Before commit 6cdf3037 ("powerpc/kvm/book3s: Use kvm helpers
to walk shadow or secondary table") we called __find_linux_pte() with
a page table pointer from a kvm_nested_guest struct but
now we rely on kvmhv_find_nested() which takes an L1 LPID and returns
a kvm_nested_guest pointer, however we pass a L0 LPID there and
the L2 guest hangs.

This fixes the LPID passed to kvmppc_hv_handle_set_rc().

Fixes: 6cdf3037 ("powerpc/kvm/book3s: Use kvm helpers to walk shadow or secondary table")
Signed-off-by: NAlexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200611030559.75257-1-aik@ozlabs.ru

Mark switch cases where we are expecting to fall through.

Fix the following warning through the use of the new the new
pseudo-keyword fallthrough;

arch/nios2/kernel/signal.c:254:12: warning: this statement may fall through [-Wimplicit-fallthrough=]
  254 |    restart = -2;
      |    ~~~~~~~~^~~~
arch/nios2/kernel/signal.c:255:3: note: here
  255 |   case ERESTARTNOHAND:
      |   ^~~~
Reported-by: NChristian Brauner <christian.brauner@ubuntu.com>
Signed-off-by: NGustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: NLey Foon Tan <ley.foon.tan@intel.com>

The patch introducing the struct was probably never compile tested,
because it sets a handler with a wrong function signature. Wrap the
handler into a functions with the correct signature to fix the build.

Fixes: 0f1c9688 ("tty/sysrq: alpha: export and use __sysrq_get_key_op()")
Cc: Emil Velikov <emil.l.velikov@gmail.com>
Signed-off-by: NJoerg Roedel <jroedel@suse.de>
Reviewed-by: NGuenter Roeck <linux@roeck-us.net>
Tested-by: NGuenter Roeck <linux@roeck-us.net>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

__kvm_set_memory_region does not use the hva at all, so trying to
catch use-after-delete is pointless and, worse, it fails access_ok
now that we apply it to all memslots including private kernel ones.
This fixes an AVIC regression.

Fixes: 09d952c9 ("KVM: check userspace_addr for all memslots")
Reported-by: NMaxim Levitsky <mlevitsk@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

'Page not present' event may or may not get injected depending on
guest's state. If the event wasn't injected, there is no need to
inject the corresponding 'page ready' event as the guest may get
confused. E.g. Linux thinks that the corresponding 'page not present'
event wasn't delivered *yet* and allocates a 'dummy entry' for it.
This entry is never freed.

Note, 'wakeup all' events have no corresponding 'page not present'
event and always get injected.

s390 seems to always be able to inject 'page not present', the
change is effectively a nop.
Suggested-by: NVivek Goyal <vgoyal@redhat.com>
Signed-off-by: NVitaly Kuznetsov <vkuznets@redhat.com>
Message-Id: <20200610175532.779793-2-vkuznets@redhat.com>
Fixes: https://bugzilla.kernel.org/show_bug.cgi?id=208081Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

The pointer s is being assigned a value that is never read, the
assignment is redundant and can be removed.

Addresses-Coverity: ("Unused value")
Signed-off-by: NColin Ian King <colin.king@canonical.com>
Message-Id: <20200609233121.1118683-1-colin.king@canonical.com>
Fixes: 7837699f ("KVM: In kernel PIT model")
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

When userspace configures KVM_GUESTDBG_SINGLESTEP, KVM will manage the
presence of X86_EFLAGS_TF via kvm_set/get_rflags on vcpus. The actual
rflag bit is therefore hidden from callers.

That includes init_emulate_ctxt() which uses the value returned from
kvm_get_flags() to set ctxt->tf. As a result, x86_emulate_instruction()
will skip a single step, leaving singlestep_rip stale and not returning
to userspace.

This resolves the issue by observing the vcpu guest_debug configuration
alongside ctxt->tf in x86_emulate_instruction(), performing the single
step if set.

Cc: stable@vger.kernel.org
Signed-off-by: NFelipe Franciosi <felipe@nutanix.com>
Message-Id: <20200519081048.8204-1-felipe@nutanix.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Consult only the basic exit reason, i.e. bits 15:0 of vmcs.EXIT_REASON,
when determining whether a nested VM-Exit should be reflected into L1 or
handled by KVM in L0.

For better or worse, the switch statement in nested_vmx_exit_reflected()
currently defaults to "true", i.e. reflects any nested VM-Exit without
dedicated logic.  Because the case statements only contain the basic
exit reason, any VM-Exit with modifier bits set will be reflected to L1,
even if KVM intended to handle it in L0.

Practically speaking, this only affects EXIT_REASON_MCE_DURING_VMENTRY,
i.e. a #MC that occurs on nested VM-Enter would be incorrectly routed to
L1, as "failed VM-Entry" is the only modifier that KVM can currently
encounter.  The SMM modifiers will never be generated as KVM doesn't
support/employ a SMI Transfer Monitor.  Ditto for "exit from enclave",
as KVM doesn't yet support virtualizing SGX, i.e. it's impossible to
enter an enclave in a KVM guest (L1 or L2).

Fixes: 644d711a ("KVM: nVMX: Deciding if L0 or L1 should handle an L2 exit")
Cc: Jim Mattson <jmattson@google.com>
Cc: Xiaoyao Li <xiaoyao.li@intel.com>
Cc: stable@vger.kernel.org
Signed-off-by: NSean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <20200227174430.26371-1-sean.j.christopherson@intel.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

The kbuild test robot reported this warning:

  arch/x86/kernel/cpu/mce/dev-mcelog.c: In function 'dev_mcelog_init_device':
  arch/x86/kernel/cpu/mce/dev-mcelog.c:346:2: warning: 'strncpy' output \
    truncated before terminating nul copying 12 bytes from a string of the \
    same length [-Wstringop-truncation]

This is accurate, but I don't care that the trailing NUL character isn't
copied. The string being copied is just a magic number signature so that
crash dump tools can be sure they are decoding the right blob of memory.

Use memcpy() instead of strncpy().

Fixes: d8ecca40 ("x86/mce/dev-mcelog: Dynamically allocate space for machine check records")
Reported-by: Nkbuild test robot <lkp@intel.com>
Signed-off-by: NTony Luck <tony.luck@intel.com>
Signed-off-by: NBorislav Petkov <bp@suse.de>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20200527182808.27737-1-tony.luck@intel.com

An interesting thing happened when a guest Linux instance took a machine
check. The VMM unmapped the bad page from guest physical space and
passed the machine check to the guest.

Linux took all the normal actions to offline the page from the process
that was using it. But then guest Linux crashed because it said there
was a second machine check inside the kernel with this stack trace:

do_memory_failure
    set_mce_nospec
         set_memory_uc
              _set_memory_uc
                   change_page_attr_set_clr
                        cpa_flush
                             clflush_cache_range_opt

This was odd, because a CLFLUSH instruction shouldn't raise a machine
check (it isn't consuming the data). Further investigation showed that
the VMM had passed in another machine check because is appeared that the
guest was accessing the bad page.

Fix is to check the scope of the poison by checking the MCi_MISC register.
If the entire page is affected, then unmap the page. If only part of the
page is affected, then mark the page as uncacheable.

This assumes that VMMs will do the logical thing and pass in the "whole
page scope" via the MCi_MISC register (since they unmapped the entire
page).

  [ bp: Adjust to x86/entry changes. ]

Fixes: 284ce401 ("x86/memory_failure: Introduce {set, clear}_mce_nospec()")
Reported-by: NJue Wang <juew@google.com>
Signed-off-by: NTony Luck <tony.luck@intel.com>
Signed-off-by: NBorislav Petkov <bp@suse.de>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Tested-by: NJue Wang <juew@google.com>
Cc: <stable@vger.kernel.org>
Link: https://lkml.kernel.org/r/20200520163546.GA7977@agluck-desk2.amr.corp.intel.com

The entry rework moved interrupt entry code from the irqentry to the
noinstr section which made the irqentry section empty.

This breaks boundary checks which rely on the __irqentry_text_start/end
markers to find out whether a function in a stack trace is
interrupt/exception entry code. This affects the function graph tracer and
filter_irq_stacks().

As the IDT entry points are all sequentialy emitted this is rather simple
to unbreak by injecting __irqentry_text_start/end as global labels.

To make this work correctly:

  - Remove the IRQENTRY_TEXT section from the x86 linker script
  - Define __irqentry so it breaks the build if it's used
  - Adjust the entry mirroring in PTI
  - Remove the redundant kprobes and unwinder bound checks
Reported-by: NQian Cai <cai@lca.pw>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

vmlinux.o: warning: objtool: exc_page_fault()+0x9: call to read_cr2() leaves .noinstr.text section
vmlinux.o: warning: objtool: exc_page_fault()+0x24: call to prefetchw() leaves .noinstr.text section
vmlinux.o: warning: objtool: exc_page_fault()+0x21: call to kvm_handle_async_pf.isra.0() leaves .noinstr.text section
vmlinux.o: warning: objtool: exc_nmi()+0x1cc: call to write_cr2() leaves .noinstr.text section
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20200603114052.243227806@infradead.org

vmlinux.o: warning: objtool: exc_debug()+0xbb: call to clear_ti_thread_flag.constprop.0() leaves .noinstr.text section
vmlinux.o: warning: objtool: noist_exc_debug()+0x55: call to clear_ti_thread_flag.constprop.0() leaves .noinstr.text section

Rework things so that handle_debug() looses the noinstr and move the
clear_thread_flag() into that.
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20200603114052.127756554@infradead.org

vmlinux.o: warning: objtool: rcu_dynticks_eqs_exit()+0x33: call to arch_atomic_and.constprop.0() leaves .noinstr.text section
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20200603114052.070166551@infradead.org

vmlinux.o: warning: objtool: lockdep_hardirqs_on()+0x65: call to arch_local_save_flags() leaves .noinstr.text section
vmlinux.o: warning: objtool: lockdep_hardirqs_off()+0x5d: call to arch_local_save_flags() leaves .noinstr.text section
vmlinux.o: warning: objtool: lock_is_held_type()+0x35: call to arch_local_irq_save() leaves .noinstr.text section
vmlinux.o: warning: objtool: check_preemption_disabled()+0x31: call to arch_local_save_flags() leaves .noinstr.text section
vmlinux.o: warning: objtool: check_preemption_disabled()+0x33: call to arch_irqs_disabled_flags() leaves .noinstr.text section
vmlinux.o: warning: objtool: lock_is_held_type()+0x2f: call to native_irq_disable() leaves .noinstr.text section
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20200603114052.012171668@infradead.org

vmlinux.o: warning: objtool: exc_debug()+0x21: call to native_get_debugreg() leaves .noinstr.text section
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20200603114051.954401211@infradead.org

 - Move load_current_idt() out of line and replace the hideous comment with
   a lockdep assert. This allows to make idt_table and idt_descr static.

 - Mark idt_table read only after the IDT initialization is complete.

 - Shuffle code around to consolidate the #ifdef sections into one.

 - Adapt the F00F bug code.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20200528145523.084915381@linutronix.de

No point in having all the IDT cruft in trap_init(). Move it into the IDT
code and fixup the comments.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20200528145522.992376498@linutronix.de

Use the actual struct size to calculate the IDT table size instead of
hardcoded values.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20200528145522.898591501@linutronix.de

The difference between 32 and 64 bit vs. early #PF handling is not
documented. Replace the FIXME at idt_setup_early_pf() with proper comments.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20200528145522.807135882@linutronix.de

Since 8175cfbbbfcb ("x86/idt: Remove update_intr_gate()") set_intr_gate()
and idt_setup_from_table() are only called from __init functions. Mark them
as well.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20200528145522.715816477@linutronix.de

The typical pattern for trace_hardirqs_off_prepare() is:

  ENTRY
    lockdep_hardirqs_off(); // because hardware
    ... do entry magic
    instrumentation_begin();
    trace_hardirqs_off_prepare();
    ... do actual work
    trace_hardirqs_on_prepare();
    lockdep_hardirqs_on_prepare();
    instrumentation_end();
    ... do exit magic
    lockdep_hardirqs_on();

which shows that it's named wrong, rename it to
trace_hardirqs_off_finish(), as it concludes the hardirq_off transition.

Also, given that the above is the only correct order, make the traditional
all-in-one trace_hardirqs_off() follow suit.
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20200529213321.415774872@infradead.org

Because:

  irq_enter_rcu() includes lockdep_hardirq_enter()
  irq_exit_rcu() does *NOT* include lockdep_hardirq_exit()

Which resulted in two 'stray' lockdep_hardirq_exit() calls in
idtentry.h, and me spending a long time trying to find the matching
enter calls.
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20200529213321.359433429@infradead.org

Both #DB itself, as all other IST users (NMI, #MC) now clear DR7 on
entry. Combined with not allowing breakpoints on entry/noinstr/NOKPROBE
text and no single step (EFLAGS.TF) inside the #DB handler should guarantee
no nested #DB.
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20200529213321.303027161@infradead.org