x86/entry: Convert double fault exception to IDTENTRY_DF

Convert #DF to IDTENTRY_DF
  - Implement the C entry point with DEFINE_IDTENTRY_DF
  - Emit the ASM stub with DECLARE_IDTENTRY_DF on 64bit
  - Remove the ASM idtentry in 64bit
  - Adjust the 32bit shim code
  - Fixup the XEN/PV code
  - Remove the old prototypes

No functional change.

Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Alexandre Chartre <[email protected]>
Acked-by: Peter Zijlstra <[email protected]>
Acked-by: Andy Lutomirski <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

x86/idtentry: Provide IDTENTRY_DF

Provide a separate macro for #DF as this needs to emit paranoid only code
and has also a special ASM stub in 32bit.

Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Alexandre Chartre <[email protected]>
Acked-by: Peter Zijlstra <[email protected]>
Acked-by: Andy Lutomirski <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

x86/mce: Address objtools noinstr complaints

Mark the relevant functions noinstr, use the plain non-instrumented MSR
accessors. The only odd part is the instrumentation_begin()/end() pair around the
indirect machine_check_vector() call as objtool can't figure that out. The
possible invoked functions are annotated correctly.

Also use notrace variant of nmi_enter/exit(). If MCEs happen then hardware
latency tracing is the least of the worries.

Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Alexandre Chartre <[email protected]>
Acked-by: Peter Zijlstra <[email protected]>
Acked-by: Andy Lutomirski <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

x86/traps: Address objtool noinstr complaints in #DB

The functions invoked from handle_debug() can be instrumented. Tell objtool
about it.

Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Alexandre Chartre <[email protected]>
Acked-by: Peter Zijlstra <[email protected]>
Acked-by: Andy Lutomirski <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

x86/traps: Restructure #DB handling

Now that there are separate entry points, move the kernel/user_mode specifc
checks into the entry functions so the common handling code does not need
the extra mode checks. Make the code more readable while at it.

Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Alexandre Chartre <[email protected]>
Acked-by: Peter Zijlstra <[email protected]>
Acked-by: Andy Lutomirski <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

x86/entry: Implement user mode C entry points for #DB and #MCE

The MCE entry point uses the same mechanism as the IST entry point for
now. For #DB split the inner workings and just keep the nmi_enter/exit()
magic in the IST variant. Fixup the ASM code to emit the proper
noist_##cfunc call.

Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Alexandre Chartre <[email protected]>
Acked-by: Peter Zijlstra <[email protected]>
Acked-by: Andy Lutomirski <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

x86/idtentry: Provide IDTRENTRY_NOIST variants for #DB and #MC

Provide NOIST entry point macros which allows to implement NOIST variants
of the C entry points. These are invoked when #DB or #MC enter from user
space. This allows explicit handling of the difference between user mode
and kernel mode entry later.

Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Alexandre Chartre <[email protected]>
Acked-by: Peter Zijlstra <[email protected]>
Acked-by: Andy Lutomirski <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

x86/entry/64: Remove error code clearing from #DB and #MCE ASM stub

The C entry points do not expect an error code.

Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Alexandre Chartre <[email protected]>
Acked-by: Peter Zijlstra <[email protected]>
Acked-by: Andy Lutomirski <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

x86/entry: Convert Debug exception to IDTENTRY_DB

Convert #DB to IDTENTRY_ERRORCODE:
  - Implement the C entry point with DEFINE_IDTENTRY_DB
  - Emit the ASM stub with DECLARE_IDTENTRY
  - Remove the ASM idtentry in 64bit
  - Remove the open coded ASM entry code in 32bit
  - Fixup the XEN/PV code
  - Remove the old prototypes

No functional change.

Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Alexandre Chartre <[email protected]>
Acked-by: Peter Zijlstra <[email protected]>
Acked-by: Andy Lutomirski <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

x86/db: Split out dr6/7 handling

DR6/7 should be handled before nmi_enter() is invoked and restore after
nmi_exit() to minimize the exposure.

Split it out into helper inlines and bring it into the correct order.

Signed-off-by: Peter Zijlstra <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Alexandre Chartre <[email protected]>
Acked-by: Andy Lutomirski <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

x86/nmi: Protect NMI entry against instrumentation

Mark all functions in the fragile code parts noinstr or force inlining so
they can't be instrumented.

Also make the hardware latency tracer invocation explicit outside of
non-instrumentable section.

Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Alexandre Chartre <[email protected]>
Acked-by: Peter Zijlstra <[email protected]>
Acked-by: Andy Lutomirski <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

x86/entry: Convert NMI to IDTENTRY_NMI

Convert #NMI to IDTENTRY_NMI:
  - Implement the C entry point with DEFINE_IDTENTRY_NMI
  - Fixup the XEN/PV code
  - Remove the old prototypes

No functional change.

Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Alexandre Chartre <[email protected]>
Acked-by: Peter Zijlstra <[email protected]>
Acked-by: Andy Lutomirski <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

x86/idtentry: Provide IDTENTRY_XEN for XEN/PV

XEN/PV has special wrappers for NMI and DB exceptions. They redirect these
exceptions through regular IDTENTRY points. Provide the necessary IDTENTRY
macros to make this work

Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Alexandre Chartre <[email protected]>
Acked-by: Peter Zijlstra <[email protected]>
Acked-by: Andy Lutomirski <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

x86/mce: Use untraced rd/wrmsr in the MCE offline/crash check

mce_check_crashing_cpu() is called right at the entry of the MCE
handler. It uses mce_rdmsr() and mce_wrmsr() which are wrappers around
rdmsr() and wrmsr() to handle the MCE error injection mechanism, which is
pointless in this context, i.e. when the MCE hits an offline CPU or the
system is already marked crashing.

The MSR access can also be traced, so use the untraceable variants. This
is also safe vs. XEN paravirt as these MSRs are not affected by XEN PV
modifications.

Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Alexandre Chartre <[email protected]>
Acked-by: Peter Zijlstra <[email protected]>
Acked-by: Andy Lutomirski <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

x86/entry: Convert Machine Check to IDTENTRY_IST

Convert #MC to IDTENTRY_MCE:
  - Implement the C entry points with DEFINE_IDTENTRY_MCE
  - Emit the ASM stub with DECLARE_IDTENTRY_MCE
  - Remove the ASM idtentry in 64bit
  - Remove the open coded ASM entry code in 32bit
  - Fixup the XEN/PV code
  - Remove the old prototypes
  - Remove the error code from *machine_check_vector() as
    it is always 0 and not used by any of the functions
    it can point to. Fixup all the functions as well.

No functional change.

Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Alexandre Chartre <[email protected]>
Acked-by: Peter Zijlstra <[email protected]>
Acked-by: Andy Lutomirski <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

x86/mce: Move nmi_enter/exit() into the entry point

There is no reason to have nmi_enter/exit() in the actual MCE
handlers. Move it to the entry point. This also covers the until now
uncovered initial handler which only prints.

Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Alexandre Chartre <[email protected]>
Acked-by: Peter Zijlstra <[email protected]>
Acked-by: Andy Lutomirski <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

x86/idtentry: Provide IDTENTRY_IST

Same as IDTENTRY but for exceptions which run on Interrupt Stacks (IST) on
64bit. For 32bit this maps to IDTENTRY.

There are 3 variants which will be used:
      IDTENTRY_MCE
      IDTENTRY_DB
      IDTENTRY_NMI

These map to IDTENTRY_IST, but only the MCE and DB variants are emitting
ASM code as the NMI entry needs hand crafted ASM still.

The function defines do not contain any idtenter/exit calls as these
exceptions need special treatment.

Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Alexandre Chartre <[email protected]>
Acked-by: Peter Zijlstra <[email protected]>
Acked-by: Andy Lutomirski <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

x86/traps: Split int3 handler up

For code simplicity split up the int3 handler into a kernel and user part
which makes the code flow simpler to understand.

Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Alexandre Chartre <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

x86/entry: Convert INT3 exception to IDTENTRY_RAW

Convert #BP to IDTENTRY_RAW:
  - Implement the C entry point with DEFINE_IDTENTRY_RAW
  - Invoke idtentry_enter/exit() from the function body
  - Emit the ASM stub with DECLARE_IDTENTRY_RAW
  - Remove the ASM idtentry in 64bit
  - Remove the open coded ASM entry code in 32bit
  - Fixup the XEN/PV code
  - Remove the old prototypes

No functional change.

This could be a plain IDTENTRY, but as Peter pointed out INT3 is broken
vs. the static key in the context tracking code as this static key might be
in the state of being patched and has an int3 which would recurse forever.
IDTENTRY_RAW is therefore chosen to allow addressing this issue without
lots of code churn.

Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Alexandre Chartre <[email protected]>
Acked-by: Peter Zijlstra <[email protected]>
Acked-by: Andy Lutomirski <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

x86/idtentry: Provide IDTENTRY_RAW

Some exception handlers need to do extra work before any of the entry
helpers are invoked. Provide IDTENTRY_RAW for this.

Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Alexandre Chartre <[email protected]>
Acked-by: Peter Zijlstra <[email protected]>
Acked-by: Andy Lutomirski <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

x86/int3: Inline bsearch()

Avoid calling out to bsearch() by inlining it, for normal kernel configs
this was the last external call and poke_int3_handler() is now fully self
sufficient -- no calls to external code.

Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Alexandre Chartre <[email protected]>
Acked-by: Andy Lutomirski <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

lib/bsearch: Provide __always_inline variant

For code that needs the ultimate performance (it can inline the @cmp
function too) or simply needs to avoid calling external functions for
whatever reason, provide an __always_inline variant of bsearch().

[ tglx: Renamed to __inline_bsearch() as suggested by Andy ]

Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Alexandre Chartre <[email protected]>
Acked-by: Andy Lutomirski <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

x86/int3: Avoid atomic instrumentation

Use arch_atomic_*() and __READ_ONCE() to ensure nothing untoward
creeps in and ruins things.

That is; this is the INT3 text poke handler, strictly limit the code
that runs in it, lest it inadvertenly hits yet another INT3.

Reported-by: Thomas Gleixner <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Masami Hiramatsu <[email protected]>
Reviewed-by: Alexandre Chartre <[email protected]>
Acked-by: Andy Lutomirski <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

x86/int3: Ensure that poke_int3_handler() is not traced

In order to ensure poke_int3_handler() is completely self contained -- this
is called while modifying other text, imagine the fun of hitting another
INT3 -- ensure that everything it uses is not traced.

The primary means here is to force inlining; bsearch() is notrace because
all of lib/ is.

Signed-off-by: Thomas Gleixner <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Alexandre Chartre <[email protected]>
Acked-by: Andy Lutomirski <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

x86/entry/32: Convert IRET exception to IDTENTRY_SW

Convert the IRET exception handler to IDTENTRY_SW. This is slightly
different than the conversions of hardware exceptions as the IRET exception
is invoked via an exception table when IRET faults. So it just uses the
IDTENTRY_SW mechanism for consistency. It does not emit ASM code as it does
not fit the other idtentry exceptions.

  - Implement the C entry point with DEFINE_IDTENTRY_SW() which maps to
    DEFINE_IDTENTRY()
  - Fixup the XEN/PV code
  - Remove the old prototypes
  - Remove the RCU warning as the new entry macro ensures correctness

No functional change.

Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Alexandre Chartre <[email protected]>
Acked-by: Peter Zijlstra <[email protected]>
Acked-by: Andy Lutomirski <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

x86/entry: Convert SIMD coprocessor error exception to IDTENTRY

Convert #XF to IDTENTRY_ERRORCODE:
  - Implement the C entry point with DEFINE_IDTENTRY
  - Emit the ASM stub with DECLARE_IDTENTRY
  - Handle INVD_BUG in C
  - Remove the ASM idtentry in 64bit
  - Remove the open coded ASM entry code in 32bit
  - Fixup the XEN/PV code
  - Remove the old prototypes
  - Remove the RCU warning as the new entry macro ensures correctness

No functional change.

Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Alexandre Chartre <[email protected]>
Acked-by: Peter Zijlstra <[email protected]>
Acked-by: Andy Lutomirski <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

x86/entry: Convert Alignment check exception to IDTENTRY

Convert #AC to IDTENTRY_ERRORCODE:
  - Implement the C entry point with DEFINE_IDTENTRY
  - Emit the ASM stub with DECLARE_IDTENTRY
  - Remove the ASM idtentry in 64bit
  - Remove the open coded ASM entry code in 32bit
  - Fixup the XEN/PV code
  - Remove the old prototypes
  - Remove the RCU warning as the new entry macro ensures correctness

No functional change.

Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Alexandre Chartre <[email protected]>
Acked-by: Peter Zijlstra <[email protected]>
Acked-by: Andy Lutomirski <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

x86/entry: Convert Coprocessor error exception to IDTENTRY

Convert #MF to IDTENTRY_ERRORCODE:
  - Implement the C entry point with DEFINE_IDTENTRY
  - Emit the ASM stub with DECLARE_IDTENTRY
  - Remove the ASM idtentry in 64bit
  - Remove the open coded ASM entry code in 32bit
  - Fixup the XEN/PV code
  - Remove the old prototypes
  - Remove the RCU warning as the new entry macro ensures correctness

No functional change.

Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Alexandre Chartre <[email protected]>
Acked-by: Peter Zijlstra <[email protected]>
Acked-by: Andy Lutomirski <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

x86/entry: Convert Spurious interrupt bug exception to IDTENTRY

Convert #SPURIOUS to IDTENTRY_ERRORCODE:
  - Implement the C entry point with DEFINE_IDTENTRY
  - Emit the ASM stub with DECLARE_IDTENTRY
  - Remove the ASM idtentry in 64bit
  - Remove the open coded ASM entry code in 32bit
  - Fixup the XEN/PV code
  - Remove the old prototypes

No functional change.

Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Alexandre Chartre <[email protected]>
Acked-by: Peter Zijlstra <[email protected]>
Acked-by: Andy Lutomirski <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

x86/entry: Convert General protection exception to IDTENTRY

Convert #GP to IDTENTRY_ERRORCODE:
  - Implement the C entry point with DEFINE_IDTENTRY
  - Emit the ASM stub with DECLARE_IDTENTRY
  - Remove the ASM idtentry in 64bit
  - Remove the open coded ASM entry code in 32bit
  - Fixup the XEN/PV code
  - Remove the old prototypes
  - Remove the RCU warning as the new entry macro ensures correctness

No functional change.

Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Alexandre Chartre <[email protected]>
Acked-by: Peter Zijlstra <[email protected]>
Acked-by: Andy Lutomirski <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

x86/entry: Convert Stack segment exception to IDTENTRY

Convert #SS to IDTENTRY_ERRORCODE:
  - Implement the C entry point with DEFINE_IDTENTRY
  - Emit the ASM stub with DECLARE_IDTENTRY
  - Remove the ASM idtentry in 64bit
  - Remove the open coded ASM entry code in 32bit
  - Fixup the XEN/PV code
  - Remove the old prototypes

No functional change.

Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Alexandre Chartre <[email protected]>
Acked-by: Peter Zijlstra <[email protected]>
Acked-by: Andy Lutomirski <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

x86/entry: Convert Segment not present exception to IDTENTRY

Convert #NP to IDTENTRY_ERRORCODE:
  - Implement the C entry point with DEFINE_IDTENTRY
  - Emit the ASM stub with DECLARE_IDTENTRY
  - Remove the ASM idtentry in 64bit
  - Remove the open coded ASM entry code in 32bit
  - Fixup the XEN/PV code
  - Remove the old prototypes

No functional change.

Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Alexandre Chartre <[email protected]>
Acked-by: Andy Lutomirski <[email protected]>
Acked-by: Peter Zijlstra <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

x86/entry: Convert Invalid TSS exception to IDTENTRY

Convert #TS to IDTENTRY_ERRORCODE:
  - Implement the C entry point with DEFINE_IDTENTRY
  - Emit the ASM stub with DECLARE_IDTENTRY
  - Remove the ASM idtentry in 64bit
  - Remove the open coded ASM entry code in 32bit
  - Fixup the XEN/PV code
  - Remove the old prototypes

No functional change.

Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Alexandre Chartre <[email protected]>
Acked-by: Andy Lutomirski <[email protected]>
Acked-by: Peter Zijlstra <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

x86/idtentry: Provide IDTENTRY_ERRORCODE

Same as IDTENTRY but the C entry point has an error code argument.

Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Alexandre Chartre <[email protected]>
Acked-by: Andy Lutomirski <[email protected]>
Acked-by: Peter Zijlstra <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

x86/entry: Convert Coprocessor segment overrun exception to IDTENTRY

Convert #OLD_MF to IDTENTRY:
  - Implement the C entry point with DEFINE_IDTENTRY
  - Emit the ASM stub with DECLARE_IDTENTRY
  - Remove the ASM idtentry in 64bit
  - Remove the open coded ASM entry code in 32bit
  - Fixup the XEN/PV code
  - Remove the old prototypes

No functional change.

Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Alexandre Chartre <[email protected]>
Acked-by: Andy Lutomirski <[email protected]>
Acked-by: Peter Zijlstra <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

x86/entry: Convert Device not available exception to IDTENTRY

Convert #NM to IDTENTRY:
  - Implement the C entry point with DEFINE_IDTENTRY
  - Emit the ASM stub with DECLARE_IDTENTRY
  - Remove the ASM idtentry in 64bit
  - Remove the open coded ASM entry code in 32bit
  - Fixup the XEN/PV code
  - Remove the old prototypes
  - Remove the RCU warning as the new entry macro ensures correctness

No functional change.

Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Alexandre Chartre <[email protected]>
Acked-by: Andy Lutomirski <[email protected]>
Acked-by: Peter Zijlstra <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

x86/entry: Convert Invalid Opcode exception to IDTENTRY

Convert #UD to IDTENTRY:
  - Implement the C entry point with DEFINE_IDTENTRY
  - Emit the ASM stub with DECLARE_IDTENTRY
  - Remove the ASM idtentry in 64bit
  - Remove the open coded ASM entry code in 32bit
  - Fixup the XEN/PV code
  - Fixup the FOOF bug call in fault.c
  - Remove the old prototypes

No functional change.

Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Alexandre Chartre <[email protected]>
Acked-by: Andy Lutomirski <[email protected]>
Acked-by: Peter Zijlstra <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

x86/entry: Convert Bounds exception to IDTENTRY

Convert #BR to IDTENTRY:
  - Implement the C entry point with DEFINE_IDTENTRY
  - Emit the ASM stub with DECLARE_IDTENTRY
  - Remove the ASM idtentry in 64bit
  - Remove the open coded ASM entry code in 32bit
  - Fixup the XEN/PV code
  - Remove the old prototypes
  - Remove the RCU warning as the new entry macro ensures correctness

No functional change.

Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Alexandre Chartre <[email protected]>
Acked-by: Andy Lutomirski <[email protected]>
Acked-by: Peter Zijlstra <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

x86/entry: Convert Overflow exception to IDTENTRY

Convert #OF to IDTENTRY:
  - Implement the C entry point with DEFINE_IDTENTRY
  - Emit the ASM stub with DECLARE_IDTENTRY
  - Remove the ASM idtentry in 64bit
  - Remove the open coded ASM entry code in 32bit
  - Fixup the XEN/PV code
  - Remove the old prototypes

No functional change.

Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Alexandre Chartre <[email protected]>
Acked-by: Andy Lutomirski <[email protected]>
Acked-by: Peter Zijlstra <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

x86/entry: Convert Divide Error to IDTENTRY

Convert #DE to IDTENTRY:
  - Implement the C entry point with DEFINE_IDTENTRY
  - Emit the ASM stub with DECLARE_IDTENTRY
  - Remove the ASM idtentry in 64bit
  - Remove the open coded ASM entry code in 32bit
  - Fixup the XEN/PV code

No functional change.

Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Alexandre Chartre <[email protected]>
Acked-by: Peter Zijlstra <[email protected]>
Acked-by: Andy Lutomirski <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

x86/traps: Prepare for using DEFINE_IDTENTRY

Prepare for using IDTENTRY to define the C exception/trap entry points. It
would be possible to glue this into the existing macro maze, but it's
simpler and better to read at the end to just make them distinct.

Provide a trivial inline helper to read the trap address and add a comment
explaining the logic behind it.

The existing macros will be removed once all instances are converted.

Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Alexandre Chartre <[email protected]>
Acked-by: Peter Zijlstra <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

x86/entry/common: Provide idtentry_enter/exit()

Provide functions which handle the low level entry and exit similar to
enter/exit from user mode.

Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Alexandre Chartre <[email protected]>
Acked-by: Peter Zijlstra <[email protected]>
Acked-by: Andy Lutomirski <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

x86/idtentry: Provide macros to define/declare IDT entry points

Provide DECLARE/DEFINE_IDTENTRY() macros.

DEFINE_IDTENTRY() provides a wrapper which acts as the function
definition. The exception handler body is just appended to it with curly
brackets. The entry point is marked noinstr so that irq tracing and the
enter_from_user_mode() can be moved into the C-entry point. As all
C-entries use the same macro (or a later variant) the necessary entry
handling can be implemented at one central place.

DECLARE_IDTENTRY() provides the function prototypes:
  - The C entry point       cfunc
  - The ASM entry point asm_cfunc
  - The XEN/PV entry point xen_asm_cfunc

They all follow the same naming convention.

When included from ASM code DECLARE_IDTENTRY() is a macro which emits the
low level entry point in assembly by instantiating idtentry.

IDTENTRY is the simplest variant which just has a pt_regs argument. It's
going to be used for all exceptions which have no error code.

Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Alexandre Chartre <[email protected]>
Acked-by: Andy Lutomirski <[email protected]>
Acked-by: Peter Zijlstra <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

x86/entry/32: Provide macro to emit IDT entry stubs

32 and 64 bit have unnecessary different ways to populate the exception
entry code. Provide a idtentry macro which allows to consolidate all of
that.

Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Alexandre Chartre <[email protected]>
Acked-by: Andy Lutomirski <[email protected]>
Acked-by: Peter Zijlstra <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

x86/entry/64: Provide sane error entry/exit

For gradual conversion provide a macro parameter and the required code
which allows to handle instrumentation and interrupt flags tracking in C.

Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Alexandre Chartre <[email protected]>
Acked-by: Peter Zijlstra <[email protected]>
Acked-by: Andy Lutomirski <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

x86/entry: Distangle idtentry

idtentry is a completely unreadable maze. Split it into distinct idtentry
variants which only contain the minimal code:

  - idtentry for regular exceptions
  - idtentry_mce_debug for #MCE and #DB
  - idtentry_df for #DF

The generated binary code is equivalent.

Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Alexandre Chartre <[email protected]>
Acked-by: Peter Zijlstra <[email protected]>
Acked-by: Andy Lutomirski <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

x86/entry/64: Reorder idtentries

Move them all together so verifying the cleanup patches for binary
equivalence will be easier.

Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Alexandre Chartre <[email protected]>
Acked-by: Andy Lutomirski <[email protected]>
Acked-by: Peter Zijlstra <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

x86/traps: Split trap numbers out in a separate header

So they can be used in ASM code. For this it is also necessary to convert
them to defines. Will be used for the rework of the entry code.

Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Andy Lutomirski <[email protected]>
Reviewed-by: Alexandre Chartre <[email protected]>
Acked-by: Peter Zijlstra <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

x86/traps: Make interrupt enable/disable symmetric in C code

Traps enable interrupts conditionally but rely on the ASM return code to
disable them again. That results in redundant interrupt disable and trace
calls.

Make the trap handlers disable interrupts before returning to avoid that,
which allows simplification of the ASM entry code in follow up changes.

Originally-by: Peter Zijlstra <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Alexandre Chartre <[email protected]>
Acked-by: Peter Zijlstra <[email protected]>
Acked-by: Andy Lutomirski <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

x86/entry/64: Use native swapgs in asm_load_gs_index()

When PARAVIRT_XXL is in use, then load_gs_index() uses xen_load_gs_index()
and asm_load_gs_index() is unused.

It's therefore pointless to use the paravirtualized SWAPGS implementation
in asm_load_gs_index(). Switch it to a plain swapgs.

Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Steven Rostedt (VMware) <[email protected]>
Acked-by: Juergen Gross <[email protected]>
Acked-by: Peter Zijlstra <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

x86/entry: Disable interrupts for native_load_gs_index() in C code

There is absolutely no point in doing this in ASM code. Move it to C.

Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Alexandre Chartre <[email protected]>
Acked-by: Peter Zijlstra <[email protected]>
Acked-by: Andy Lutomirski <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

x86/traps: Mark sync_regs() noinstr

Replace the notrace and NOKPROBE annotations with noinstr.

Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Alexandre Chartre <[email protected]>
Reviewed-by: Masami Hiramatsu <[email protected]>
Acked-by: Peter Zijlstra <[email protected]>
Acked-by: Andy Lutomirski <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

x86/traps: Mark fixup_bad_iret() noinstr

This is called from deep entry ASM in a situation where instrumentation
will cause more harm than providing useful information.

Switch from memmove() to memcpy() because memmove() can't be called
from noinstr code.

Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Alexandre Chartre <[email protected]>
Reviewed-by: Masami Hiramatsu <[email protected]>
Acked-by: Peter Zijlstra <[email protected]>
Acked-by: Andy Lutomirski <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

x86/entry: Make entry_64_compat.S objtool clean

Currently entry_64_compat is exempt from objtool, but with vmlinux
mode there is no hiding it.

Make the following changes to make it pass:

 - change entry_SYSENTER_compat to STT_NOTYPE; it's not a function
   and doesn't have function type stack setup.

 - mark all STT_NOTYPE symbols with UNWIND_HINT_EMPTY; so we do
   validate them and don't treat them as unreachable.

 - don't abuse RSP as a temp register, this confuses objtool
   mightily as it (rightfully) thinks we're doing unspeakable
   things to the stack.

Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Alexandre Chartre <[email protected]>
Acked-by: Andy Lutomirski <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

x86/speculation/mds: Mark mds_user_clear_cpu_buffers() __always_inline

Prevent the compiler from uninlining and creating traceable/probable
functions as this is invoked _after_ context tracking switched to
CONTEXT_USER and rcu idle.

Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Alexandre Chartre <[email protected]>
Acked-by: Peter Zijlstra <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

x86/entry: Move irq flags tracing to prepare_exit_to_usermode()

This is another step towards more C-code and less convoluted ASM.

Similar to the entry path, invoke the tracer before context tracking which
might turn off RCU and invoke lockdep as the last step before going back to
user space. Annotate the code sections in exit_to_user_mode() accordingly
so objtool won't complain about the tracer invocation.

Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Alexandre Chartre <[email protected]>
Acked-by: Peter Zijlstra <[email protected]>
Acked-by: Andy Lutomirski <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

x86/entry: Move irq tracing on syscall entry to C-code

Now that the C entry points are safe, move the irq flags tracing code into
the entry helper:

    - Invoke lockdep before calling into context tracking

    - Use the safe trace_hardirqs_on_prepare() trace function after context
      tracking established state and RCU is watching.

enter_from_user_mode() is also still invoked from the exception/interrupt
entry code which still contains the ASM irq flags tracing. So this is just
a redundant and harmless invocation of tracing / lockdep until these are
removed as well.

Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Alexandre Chartre <[email protected]>
Acked-by: Peter Zijlstra <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

x86/entry/common: Protect against instrumentation

Mark the various syscall entries with noinstr to protect them against
instrumentation and add the noinstrumentation_begin()/end() annotations to mark the
parts of the functions which are safe to call out into instrumentable code.

Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Alexandre Chartre <[email protected]>
Acked-by: Peter Zijlstra <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

x86/entry: Mark enter_from_user_mode() noinstr

Both the callers in the low level ASM code and __context_tracking_exit()
which is invoked from enter_from_user_mode() via user_exit_irqoff() are
marked NOKPROBE. Allowing enter_from_user_mode() to be probed is
inconsistent at best.

Aside of that while function tracing per se is safe the function trace
entry/exit points can be used via BPF as well which is not safe to use
before context tracking has reached CONTEXT_KERNEL and adjusted RCU.

Mark it noinstr which moves it into the instrumentation protected text
section and includes notrace.

Note, this needs further fixups in context tracking to ensure that the
full call chain is protected. Will be addressed in follow up changes.

Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Masami Hiramatsu <[email protected]>
Reviewed-by: Alexandre Chartre <[email protected]>
Acked-by: Peter Zijlstra <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

x86/entry/32: Move non entry code into .text section

All ASM code which is not part of the entry functionality can move out into
the .text section. No reason to keep it in the non-instrumentable entry
section.

Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Alexandre Chartre <[email protected]>
Acked-by: Peter Zijlstra <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

x86/entry/64: Move non entry code into .text section

All ASM code which is not part of the entry functionality can move out into
the .text section. No reason to keep it in the non-instrumentable entry
section.

Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Steven Rostedt (VMware) <[email protected]>
Reviewed-by: Alexandre Chartre <[email protected]>
Acked-by: Peter Zijlstra <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

x86/idt: Remove update_intr_gate()

No more users.

Signed-off-by: Thomas Gleixner <[email protected]>

bug: Annotate WARN/BUG/stackfail as noinstr safe

Warnings, bugs and stack protection fails from noinstr sections, e.g. low
level and early entry code, are likely to be fatal.

Mark them as "safe" to be invoked from noinstr protected code to avoid
annotating all usage sites. Getting the information out is important.

Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Alexandre Chartre <[email protected]>
Acked-by: Peter Zijlstra <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

lib/smp_processor_id: Move it into noinstr section

That code is already not traceable. Move it into the noinstr section so the
objtool section validation does not trigger.

Annotate the warning code as "safe". While it might be not under all
circumstances, getting the information out is important enough.

Should this ever trigger from the sensitive code which is shielded against
instrumentation, e.g. low level entry, then the printk is the least of the
worries.

Addresses the objtool warnings:
 vmlinux.o: warning: objtool: context_tracking_recursion_enter()+0x7: call to __this_cpu_preempt_check() leaves .noinstr.text section
 vmlinux.o: warning: objtool: __context_tracking_exit()+0x17: call to __this_cpu_preempt_check() leaves .noinstr.text section
 vmlinux.o: warning: objtool: __context_tracking_enter()+0x2a: call to __this_cpu_preempt_check() leaves .noinstr.text section

Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Alexandre Chartre <[email protected]>
Acked-by: Peter Zijlstra <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

context_tracking: Ensure that the critical path cannot be instrumented

context tracking lacks a few protection mechanisms against instrumentation:

 - While the core functions are marked NOKPROBE they lack protection
   against function tracing which is required as the function entry/exit
   points can be utilized by BPF.

 - static functions invoked from the protected functions need to be marked
   as well as they can be instrumented otherwise.

 - using plain inline allows the compiler to emit traceable and probable
   functions.

Fix this by marking the functions noinstr and converting the plain inlines
to __always_inline.

The NOKPROBE_SYMBOL() annotations are removed as the .noinstr.text section
is already excluded from being probed.

Cures the following objtool warnings:

 vmlinux.o: warning: objtool: enter_from_user_mode()+0x34: call to __context_tracking_exit() leaves .noinstr.text section
 vmlinux.o: warning: objtool: prepare_exit_to_usermode()+0x29: call to __context_tracking_enter() leaves .noinstr.text section
 vmlinux.o: warning: objtool: syscall_return_slowpath()+0x29: call to __context_tracking_enter() leaves .noinstr.text section
 vmlinux.o: warning: objtool: do_syscall_64()+0x7f: call to __context_tracking_enter() leaves .noinstr.text section
 vmlinux.o: warning: objtool: do_int80_syscall_32()+0x3d: call to __context_tracking_enter() leaves .noinstr.text section
 vmlinux.o: warning: objtool: do_fast_syscall_32()+0x9c: call to __context_tracking_enter() leaves .noinstr.text section

and generates new ones...

Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Masami Hiramatsu <[email protected]>
Reviewed-by: Alexandre Chartre <[email protected]>
Acked-by: Peter Zijlstra <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

x86/entry: Exclude low level entry code from sanitizing

The sanitizers are not really applicable to the fragile low level entry
code. Entry code needs to carefully setup a normal 'runtime' environment.

Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Alexandre Chartre <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

x86/entry: Remove the unused LOCKDEP_SYSEXIT cruft

No users left since two years due to commit 21d375b6b34f ("x86/entry/64:
Remove the SYSCALL64 fast path")

Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Alexandre Chartre <[email protected]>
Acked-by: Peter Zijlstra <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

x86/entry/64: Avoid pointless code when CONTEXT_TRACKING=n

GAS cannot optimize out the test and conditional jump when context tracking
is disabled and CALL_enter_from_user_mode is an empty macro.

Wrap it in #ifdeffery. Will go away once all this is moved to C.

Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Alexandre Chartre <[email protected]>
Acked-by: Frederic Weisbecker <[email protected]>
Acked-by: Andy Lutomirski <[email protected]>
Acked-by: Peter Zijlstra <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

x86/doublefault: Remove memmove() call

Use of memmove() in #DF is problematic considered tracing and other
instrumentation.

Remove the memmove() call and simply write out what needs doing; this
even clarifies the code, win-win! The code copies from the espfix64
stack to the normal task stack, there is no possible way for that to
overlap.

Survives selftests/x86, specifically sigreturn_64.

Suggested-by: Borislav Petkov <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Alexandre Chartre <[email protected]>
Acked-by: Andy Lutomirski <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

x86/hw_breakpoint: Prevent data breakpoints on cpu_entry_area

A data breakpoint near the top of an IST stack will cause unrecoverable
recursion.  A data breakpoint on the GDT, IDT, or TSS is terrifying.
Prevent either of these from happening.

Co-developed-by: Peter Zijlstra <[email protected]>
Signed-off-by: Andy Lutomirski <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Borislav Petkov <[email protected]>
Reviewed-by: Lai Jiangshan <[email protected]>
Reviewed-by: Alexandre Chartre <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

x86/idt: Keep spurious entries unset in system_vectors

With commit dc20b2d52653 ("x86/idt: Move interrupt gate initialization to
IDT code") non assigned system vectors are also marked as used in
'used_vectors' (now 'system_vectors') bitmap. This makes checks in
arch_show_interrupts() whether a particular system vector is allocated to
always pass and e.g. 'Hyper-V reenlightenment interrupts' entry always
shows up in /proc/interrupts.

Another side effect of having all unassigned system vectors marked as used
is that irq_matrix_debug_show() will wrongly count them among 'System'
vectors.

As it is now ensured that alloc_intr_gate() is not called after init, it is
possible to leave unused entries in 'system_vectors' unset to fix these
issues.

Signed-off-by: Vitaly Kuznetsov <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

x86/idt: Annotate alloc_intr_gate() with __init

There seems to be no reason to allocate interrupt gates after init. Mark
alloc_intr_gate() as __init and add WARN_ON() checks making sure it is
only used before idt_setup_apic_and_irq_gates() finalizes IDT setup and
maps all un-allocated entries to spurious entries.

Suggested-by: Thomas Gleixner <[email protected]>
Signed-off-by: Vitaly Kuznetsov <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

x86/xen: Split HVM vector callback setup and interrupt gate allocation

As a preparatory change for making alloc_intr_gate() __init split
xen_callback_vector() into callback vector setup via hypercall
(xen_setup_callback_vector()) and interrupt gate allocation
(xen_alloc_callback_vector()).

xen_setup_callback_vector() is being called twice: on init and upon
system resume from xen_hvm_post_suspend(). alloc_intr_gate() only
needs to be called once.

Suggested-by: Thomas Gleixner <[email protected]>
Signed-off-by: Vitaly Kuznetsov <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

x86/idt: Remove address operator on function machine_check()

machine_check is function address, the address operator on it is nop for
compiler.

Make it consistent with the other function addresses in the same file.

Signed-off-by: Lai Jiangshan <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

x86/entry/64: Remove unneeded kernel CR3 switching

When native_load_gs_index() fails on .Lgs_change, CR3 must be kernel
CR3. No need to switch it.

Signed-off-by: Lai Jiangshan <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

x86/entry/64: Remove an unused label

The label .Lcommon_\sym was introduced by 39e9543344fa.
(x86-64: Reduce amount of redundant code generated for invalidate_interruptNN)
And all the other relevant information was removed by 52aec3308db8
(x86/tlb: replace INVALIDATE_TLB_VECTOR by CALL_FUNCTION_VECTOR)

Signed-off-by: Lai Jiangshan <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

arm64: warn on incorrect placement of the kernel by the bootloader

Commit cfa7ede20f133c ("arm64: set TEXT_OFFSET to 0x0 in preparation for
removing it entirely") results in boot failures when booting kernels that
are built without KASLR support on broken bootloaders that ignore the
TEXT_OFFSET value passed via the header, and use the default of 0x80000
instead.

To work around this, turn CONFIG_RELOCATABLE on by default, even if KASLR
itself (CONFIG_RANDOMIZE_BASE) is turned off, and require CONFIG_EXPERT
to be enabled to deviate from this. Then, emit a warning into the kernel
log if we are not booting via the EFI stub (which is permitted to deviate
from the placement restrictions) and the kernel base address is not placed
according to the rules as laid out in Documentation/arm64/booting.rst.

Signed-off-by: Ard Biesheuvel <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Will Deacon <[email protected]>

kbuild: fix broken builds because of GZIP,BZIP2,LZOP variables

Redefine GZIP, BZIP2, LZOP variables as KGZIP, KBZIP2, KLZOP resp.
GZIP, BZIP2, LZOP env variables are reserved by the tools. The original
attempt to redefine them internally doesn't work in makefiles/scripts
intercall scenarios, e.g., "make GZIP=gzip bindeb-pkg" and results in
broken builds. There can be other broken build commands because of this,
so the universal solution is to use non-reserved env variables for the
compression tools.

Fixes: 8dfb61dcbace ("kbuild: add variables for compression tools")
Signed-off-by: Denis Efremov <[email protected]>
Tested-by: Guenter Roeck <[email protected]>
Signed-off-by: Masahiro Yamada <[email protected]>

samples: binderfs: really compile this sample and fix build issues

Even after commit c624adc9cb6e ("samples: fix binderfs sample"), this
sample is never compiled.

'hostprogs' teaches Kbuild that this is a host program, but not enough
to order to compile it. You must add it to 'always-y' to really compile
it.

Since this sample has never been compiled in upstream, various issues
are left unnoticed.

[1] compilers without <linux/android/binderfs.h> are still widely used

<linux/android/binderfs.h> is only available since commit c13295ad219d
("binderfs: rename header to binderfs.h"), i.e., Linux 5.0

If your compiler is based on UAPI headers older than Linux 5.0, you
will see the following error:

  samples/binderfs/binderfs_example.c:16:10: fatal error: linux/android/binderfs.h: No such file or directory
   #include <linux/android/binderfs.h>
            ^~~~~~~~~~~~~~~~~~~~~~~~~~
  compilation terminated.

You cannot rely on compilers having such a new header.

The common approach is to install UAPI headers of this kernel into
usr/include, and then add it to the header search path.

I added 'depends on HEADERS_INSTALL' in Kconfig, and '-I usr/include'
compiler flag in Makefile.

[2] compile the sample for target architecture

Because headers_install works for the target architecture, only the
native compiler was able to build sample code that requires
'-I usr/include'.

Commit 7f3a59db274c ("kbuild: add infrastructure to build userspace
programs") added the new syntax 'userprogs' to compile user-space
programs for the target architecture.

Use it, and then 'ifndef CROSS_COMPILE' will go away.

I added 'depends on CC_CAN_LINK' because $(CC) is not necessarily
capable of linking user-space programs.

[3] use subdir-y to descend into samples/binderfs

Since this directory does not contain any kernel-space code, it has no
point in generating built-in.a or modules.order.

Replace obj-$(CONFIG_...) with subdir-$(CONFIG_...).

[4] -Wunused-variable warning

If I compile this, I see the following warning.

  samples/binderfs/binderfs_example.c: In function 'main':
  samples/binderfs/binderfs_example.c:21:9: warning: unused variable 'len' [-Wunused-variable]
     21 |  size_t len;
        |         ^~~

I removed the unused 'len'.

[5] CONFIG_ANDROID_BINDERFS is not required

Since this is a user-space standalone program, it is independent of
the kernel configuration.

Remove 'depends on ANDROID_BINDERFS'.

Fixes: 9762dc1432e1 ("samples: add binderfs sample program")
Fixes: c624adc9cb6e ("samples: fix binderfs sample")
Signed-off-by: Masahiro Yamada <[email protected]>
Acked-by: Christian Brauner <[email protected]>

i2c: Drop stray comma in MODULE_AUTHOR statements

It is not the common usage to have a comma between the name and the
email address, so remove it.

Signed-off-by: Jean Delvare <[email protected]>
Cc: Kukjin Kim <[email protected]>
Cc: Krzysztof Kozlowski <[email protected]>
Reviewed-by: Jarkko Nikula <[email protected]>
Signed-off-by: Wolfram Sang <[email protected]>

i2c: npcm7xx: npcm_i2caddr[] can be static

Fixes: f54736925a4f ("i2c: npcm7xx: Add support for slave mode for Nuvoton")
Signed-off-by: kernel test robot <[email protected]>
Signed-off-by: Wolfram Sang <[email protected]>

Merge tag 'drm-misc-next-fixes-2020-06-11' of git://anongit.freedesktop.org/drm/drm-misc into drm-next

In core, DRM connectors now notify userspace of hotplug events via
sysfs. In drivers, sun4i now uses 4 bits to store the clock's m divider;
ast sets up 24/32-bit color mode correctly.

Signed-off-by: Dave Airlie <[email protected]>
From: Thomas Zimmermann <[email protected]>
Link: https://patchwork.freedesktop.org/patch/msgid/20200611075007.GA15098@linux-uq9g

drm/ast: fix missing break in switch statement for format->cpp[0] case 4

Currently the switch statement for format->cpp[0] value 4 assigns
color_index which is never read again and then falls through to the
default case and returns. This looks like a missing break statement
bug. Fix this by adding a break statement.

Addresses-Coverity: ("Unused value")
Fixes: 259d14a76a27 ("drm/ast: Split ast_set_vbios_mode_info()")
Signed-off-by: Colin Ian King <[email protected]>
Signed-off-by: Thomas Zimmermann <[email protected]>
Tested-by: Thomas Zimmermann <[email protected]>
Reviewed-by: Thomas Zimmermann <[email protected]>
Link: https://patchwork.freedesktop.org/patch/msgid/[email protected]

printk/kdb: Redirect printk messages into kdb in any context

kdb has to get messages on consoles even when the system is stopped.
It uses kdb_printf() internally and calls console drivers on its own.

It uses a hack to reuse an existing code. It sets "kdb_trap_printk"
global variable to redirect even the normal printk() into the
kdb_printf() variant.

The variable "kdb_trap_printk" is checked in printk_default() and
it is ignored when printk is redirected to printk_safe in NMI context.
Solve this by moving the check into printk_func().

It is obvious that it is not fully safe. But it does not make things
worse. The console drivers are already called in this context by
db_printf() direct calls.

Reported-by: Sumit Garg <[email protected]>
Tested-by: Sumit Garg <[email protected]>
Reviewed-by: Daniel Thompson <[email protected]>
Acked-by: Sergey Senozhatsky <[email protected]>
Signed-off-by: Petr Mladek <[email protected]>
Link: https://lore.kernel.org/r/20200520102233.GC3464@linux-b0ei

locking/atomics: Flip fallbacks and instrumentation

Currently instrumentation of atomic primitives is done at the architecture
level, while composites or fallbacks are provided at the generic level.

The result is that there are no uninstrumented variants of the
fallbacks. Since there is now need of such variants to isolate text poke
from any form of instrumentation invert this ordering.

Doing this means moving the instrumentation into the generic code as
well as having (for now) two variants of the fallbacks.

Notes:

 - the various *cond_read* primitives are not proper fallbacks
   and got moved into linux/atomic.c. No arch_ variants are
   generated because the base primitives smp_cond_load*()
   are instrumented.

 - once all architectures are moved over to arch_atomic_ one of the
   fallback variants can be removed and some 2300 lines reclaimed.

 - atomic_{read,set}*() are no longer double-instrumented

Reported-by: Thomas Gleixner <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Acked-by: Mark Rutland <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

asm-generic/atomic: Use __always_inline for fallback wrappers

Use __always_inline for atomic fallback wrappers. When building for size
(CC_OPTIMIZE_FOR_SIZE), some compilers appear to be less inclined to
inline even relatively small static inline functions that are assumed to
be inlinable such as atomic ops. This can cause problems, for example in
UACCESS regions.

While the fallback wrappers aren't pure wrappers, they are trivial
nonetheless, and the function they wrap should determine the final
inlining policy.

For x86 tinyconfig we observe:
- vmlinux baseline: 1315988
- vmlinux with patch: 1315928 (-60 bytes)

[ tglx: Cherry-picked from KCSAN ]

Suggested-by: Mark Rutland <[email protected]>
Signed-off-by: Marco Elver <[email protected]>
Acked-by: Mark Rutland <[email protected]>
Signed-off-by: Paul E. McKenney <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>

mailbox: qcom: Add ipq6018 apcs compatible

The Qualcomm ipq6018 has apcs block, add compatible for the same. Also,
the ipq6018 apcs provides a clock functionality similar to msm8916 but
the clock driver is different.

Create a child device based on the apcs compatible for the clock
controller functionality.

Signed-off-by: Sivaprakash Murugesan <[email protected]>
Signed-off-by: Jassi Brar <[email protected]>

mailbox: qcom: Add clock driver name in apcs mailbox driver data

Some apcs mailbox devices supports a clock driver, the compatible
strings of devices supporting clock driver along with the clock driver
name are maintained in a separate structure within the mailbox driver.
And the clock driver is added based on device match.

With increase in number of devices supporting the clock feature move the
clock driver name inside the driver data. so that we can use a single
API to get the register offset of mailbox driver and clock driver name
together, and the clock driver will be added based on the driver data.

Signed-off-by: Sivaprakash Murugesan <[email protected]>
Signed-off-by: Jassi Brar <[email protected]>

riscv: set the permission of vdso_data to read-only

The original vdso_data page is empty, so the permission of the vdso_data
page can be the same with the vdso text page. After introducing the vDSO
common flow, the vdso_data is not empty and the permission should be
changed to read-only.

Signed-off-by: Vincent Chen <[email protected]>
Signed-off-by: Palmer Dabbelt <[email protected]>

riscv: use vDSO common flow to reduce the latency of the time-related functions

Even if RISC-V has supported the vDSO feature, the latency of the functions
for obtaining the system time is still expensive. It is because these
functions still trigger a corresponding system call in the process, which
slows down the response time. If we want to remove the system call to
reduce the latency, the kernel should have the ability to output the system
clock information to userspace. This patch introduces the vDSO common flow
to enable the kernel to achieve the above feature and uses "rdtime"
instruction to obtain the current time in the user space. Under this
condition, the latency cost by the ecall from U-mode to S-mode can be
eliminated. After applying this patch, the latency of gettimeofday()
measured on the HiFive unleashed board can be reduced by %61.

Signed-off-by: Vincent Chen <[email protected]>
Reviewed-by: Atish Patra <[email protected]>
Signed-off-by: Palmer Dabbelt <[email protected]>

kernel: set USER_DS in kthread_use_mm

Some architectures like arm64 and s390 require USER_DS to be set for
kernel threads to access user address space, which is the whole purpose of
kthread_use_mm, but other like x86 don't.  That has lead to a huge mess
where some callers are fixed up once they are tested on said
architectures, while others linger around and yet other like io_uring try
to do "clever" optimizations for what usually is just a trivial asignment
to a member in the thread_struct for most architectures.

Make kthread_use_mm set USER_DS, and kthread_unuse_mm restore to the
previous value instead.

Signed-off-by: Christoph Hellwig <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Tested-by: Jens Axboe <[email protected]>
Reviewed-by: Jens Axboe <[email protected]>
Acked-by: Michael S. Tsirkin <[email protected]>
Cc: Alex Deucher <[email protected]>
Cc: Al Viro <[email protected]>
Cc: Felipe Balbi <[email protected]>
Cc: Felix Kuehling <[email protected]>
Cc: Jason Wang <[email protected]>
Cc: Zhenyu Wang <[email protected]>
Cc: Zhi Wang <[email protected]>
Cc: Greg Kroah-Hartman <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Linus Torvalds <[email protected]>

kernel: better document the use_mm/unuse_mm API contract

Switch the function documentation to kerneldoc comments, and add
WARN_ON_ONCE asserts that the calling thread is a kernel thread and does
not have ->mm set (or has ->mm set in the case of unuse_mm).

Also give the functions a kthread_ prefix to better document the use case.

[[email protected]: fix a comment typo, cover the newly merged use_mm/unuse_mm caller in vfio]
Link: http://lkml.kernel.org/r/[email protected]
[[email protected]: powerpc/vas: fix up for {un}use_mm() rename]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Christoph Hellwig <[email protected]>
Signed-off-by: Stephen Rothwell <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Tested-by: Jens Axboe <[email protected]>
Reviewed-by: Jens Axboe <[email protected]>
Acked-by: Felix Kuehling <[email protected]>
Acked-by: Greg Kroah-Hartman <[email protected]> [usb]
Acked-by: Haren Myneni <[email protected]>
Cc: Alex Deucher <[email protected]>
Cc: Al Viro <[email protected]>
Cc: Felipe Balbi <[email protected]>
Cc: Jason Wang <[email protected]>
Cc: "Michael S. Tsirkin" <[email protected]>
Cc: Zhenyu Wang <[email protected]>
Cc: Zhi Wang <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Linus Torvalds <[email protected]>

kernel: move use_mm/unuse_mm to kthread.c

cover the newly merged use_mm/unuse_mm caller in vfio

Signed-off-by: Christoph Hellwig <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Acked-by: Felix Kuehling <[email protected]>
Cc: Alex Deucher <[email protected]>
Cc: Al Viro <[email protected]>
Cc: Felipe Balbi <[email protected]>
Cc: Greg Kroah-Hartman <[email protected]>
Cc: Jason Wang <[email protected]>
Cc: Jens Axboe <[email protected]>
Cc: "Michael S. Tsirkin" <[email protected]>
Cc: Zhenyu Wang <[email protected]>
Cc: Zhi Wang <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Linus Torvalds <[email protected]>

kernel: move use_mm/unuse_mm to kthread.c

Patch series "improve use_mm / unuse_mm", v2.

This series improves the use_mm / unuse_mm interface by better documenting
the assumptions, and my taking the set_fs manipulations spread over the
callers into the core API.

This patch (of 3):

Use the proper API instead.

Link: http://lkml.kernel.org/r/[email protected]
These helpers are only for use with kernel threads, and I will tie them
more into the kthread infrastructure going forward.  Also move the
prototypes to kthread.h - mmu_context.h was a little weird to start with
as it otherwise contains very low-level MM bits.

Signed-off-by: Christoph Hellwig <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Tested-by: Jens Axboe <[email protected]>
Reviewed-by: Jens Axboe <[email protected]>
Acked-by: Felix Kuehling <[email protected]>
Cc: Alex Deucher <[email protected]>
Cc: Al Viro <[email protected]>
Cc: Felipe Balbi <[email protected]>
Cc: Jason Wang <[email protected]>
Cc: "Michael S. Tsirkin" <[email protected]>
Cc: Zhenyu Wang <[email protected]>
Cc: Zhi Wang <[email protected]>
Cc: Greg Kroah-Hartman <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Link: http://lkml.kernel.org/r/[email protected]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Linus Torvalds <[email protected]>

stacktrace: cleanup inconsistent variable type

Modify the variable type of 'skip' member of struct stack_trace.
In theory, the 'skip' variable type should be unsigned int.
There are two reasons:
- The 'skip' only has two situation, 1)Positive value, 2)Zero
- The 'skip' of struct stack_trace has inconsistent type with struct
  stack_trace_data, it makes a bit confusion in the relationship between
  struct stack_trace and stack_trace_data.

Signed-off-by: Walter Wu <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Reviewed-by: Bart Van Assche <[email protected]>
Cc: Matthias Brugger <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Josh Poimboeuf <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Linus Torvalds <[email protected]>

lib: test get_count_order/long in test_bitops.c

Add some tests for get_count_order/long in test_bitops.c.

[[email protected]: define local `i']
[[email protected]: enhancement, warning fix, cleanup per Geert]
[[email protected]: fix loop bound, per Wei Yang]

Signed-off-by: Wei Yang <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Reviewed-by: Andy Shevchenko <[email protected]>
Cc: Christian Brauner <[email protected]>
Cc: Geert Uytterhoeven <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Linus Torvalds <[email protected]>

mm: add comments on pglist_data zones

While making other modifications it was easy to confuse the two struct
members node_zones and node_zonelists.  For those already familiar with
the code, this might seem to be a silly patch, but it's quite helpful to
disambiguate the similar-sounding fields

While here, add a small comment on why nr_zones isn't simply MAX_NR_ZONES

Signed-off-by: Ben Widawsky <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Reviewed-by: Andrew Morton <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Linus Torvalds <[email protected]>

ocfs2: fix spelling mistake and grammar

./ocfs2/mmap.c:65: bebongs ==> belonging

Signed-off-by: Keyur Patel <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Reviewed-by: Joseph Qi <[email protected]>
Cc: Mark Fasheh <[email protected]>
Cc: Joel Becker <[email protected]>
Cc: Junxiao Bi <[email protected]>
Cc: Changwei Ge <[email protected]>
Cc: Gang He <[email protected]>
Cc: Jun Piao <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Linus Torvalds <[email protected]>

mm/debug_vm_pgtable: fix kernel crash by checking for THP support

Architectures can have CONFIG_TRANSPARENT_HUGEPAGE enabled but no THP
support enabled based on platforms.  For ex: with 4K PAGE_SIZE ppc64
supports THP only with radix translation.

This results in below crash when running with hash translation and 4K
PAGE_SIZE.

    kernel BUG at arch/powerpc/include/asm/book3s/64/hash-4k.h:140!
    cpu 0x61: Vector: 700 (Program Check) at [c000000ff948f860]
        pc: debug_vm_pgtable+0x480/0x8b0
        lr: debug_vm_pgtable+0x474/0x8b0
    ...
        debug_vm_pgtable+0x374/0x8b0 (unreliable)
        do_one_initcall+0x98/0x4f0
        kernel_init_freeable+0x330/0x3fc
        kernel_init+0x24/0x148

Check for THP support correctly

Link: http://lkml.kernel.org/r/[email protected]
Fixes: 399145f9eb6c ("mm/debug: add tests validating architecture page table helpers")
Signed-off-by: Aneesh Kumar K.V <[email protected]>
Reviewed-by: Anshuman Khandual <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

lib: fix bitmap_parse() on 64-bit big endian archs

Commit 2d6261583be0 ("lib: rework bitmap_parse()") does not take into
account order of halfwords on 64-bit big endian architectures.  As
result (at least) Receive Packet Steering, IRQ affinity masks and
runtime kernel test "test_bitmap" get broken on s390.

[[email protected]: convert infinite while loop to a for loop]
Link: http://lkml.kernel.org/r/[email protected]
Fixes: 2d6261583be0 ("lib: rework bitmap_parse()")
Signed-off-by: Alexander Gordeev <[email protected]>
Signed-off-by: Andy Shevchenko <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Reviewed-by: Andy Shevchenko <[email protected]>
Cc: Yury Norov <[email protected]>
Cc: Amritha Nambiar <[email protected]>
Cc: Arnaldo Carvalho de Melo <[email protected]>
Cc: Chris Wilson <[email protected]>
Cc: Kees Cook <[email protected]>
Cc: Matthew Wilcox <[email protected]>
Cc: Miklos Szeredi <[email protected]>
Cc: Rasmus Villemoes <[email protected]>
Cc: Steffen Klassert <[email protected]>
Cc: "Tobin C . Harding" <[email protected]>
Cc: Vineet Gupta <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: Willem de Bruijn <[email protected]>
Cc: <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Linus Torvalds <[email protected]>