Unfortunately, my build fix for when time travel mode isn't
enabled broke time travel mode, because I forgot that we need
to use the timer time after the timer has been marked disabled,
and thus need to leave the time stored instead of zeroing it.

Fix that by splitting the inline into two, so we can call only
the _mode() one in the relevant code path.

Fixes: b482e48d29f1 ("um: fix build without CONFIG_UML_TIME_TRAVEL_SUPPORT")
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Richard Weinberger <richard@nod.at>

Pull UML updates from Richard Weinberger:

 - A new timer mode, time travel, for testing with UML

 - Many bugixes/improvements for the serial line driver

 - Various bugfixes

* tag 'for-linus-5.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rw/uml:
  um: fix build without CONFIG_UML_TIME_TRAVEL_SUPPORT
  um: Fix kcov crash during startup
  um: configs: Remove useless UEVENT_HELPER_PATH
  um: Support time travel mode
  um: Pass nsecs to os timer functions
  um: Remove drivers/ssl.h
  um: Don't garbage collect in deactivate_all_fds()
  um: Silence lockdep complaint about mmap_sem
  um: Remove locking in deactivate_all_fds()
  um: Timer code cleanup
  um: fix os_timer_one_shot()
  um: Fix IRQ controller regression on console read

Pull Kbuild updates from Masahiro Yamada:

 - remove headers_{install,check}_all targets

 - remove unreasonable 'depends on !UML' from CONFIG_SAMPLES

 - re-implement 'make headers_install' more cleanly

 - add new header-test-y syntax to compile-test headers

 - compile-test exported headers to ensure they are compilable in
   user-space

 - compile-test headers under include/ to ensure they are self-contained

 - remove -Waggregate-return, -Wno-uninitialized, -Wno-unused-value
   flags

 - add -Werror=unknown-warning-option for Clang

 - add 128-bit built-in types support to genksyms

 - fix missed rebuild of modules.builtin

 - propagate 'No space left on device' error in fixdep to Make

 - allow Clang to use its integrated assembler

 - improve some coccinelle scripts

 - add a new flag KBUILD_ABS_SRCTREE to request Kbuild to use absolute
   path for $(srctree).

 - do not ignore errors when compression utility is missing

 - misc cleanups

* tag 'kbuild-v5.3' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (49 commits)
  kbuild: use -- separater intead of $(filter-out ...) for cc-cross-prefix
  kbuild: Inform user to pass ARCH= for make mrproper
  kbuild: fix compression errors getting ignored
  kbuild: add a flag to force absolute path for srctree
  kbuild: replace KBUILD_SRCTREE with boolean building_out_of_srctree
  kbuild: remove src and obj from the top Makefile
  scripts/tags.sh: remove unused environment variables from comments
  scripts/tags.sh: drop SUBARCH support for ARM
  kbuild: compile-test kernel headers to ensure they are self-contained
  kheaders: include only headers into kheaders_data.tar.xz
  kheaders: remove meaningless -R option of 'ls'
  kbuild: support header-test-pattern-y
  kbuild: do not create wrappers for header-test-y
  kbuild: compile-test exported headers to ensure they are self-contained
  init/Kconfig: add CONFIG_CC_CAN_LINK
  kallsyms: exclude kasan local symbols on s390
  kbuild: add more hints about SUBDIRS replacement
  coccinelle: api/stream_open: treat all wait_.*() calls as blocking
  coccinelle: put_device: Add a cast to an expression for an assignment
  coccinelle: put_device: Adjust a message construction
  ...

um allocates PTE pages with __get_free_page() and uses
GFP_KERNEL | __GFP_ZERO for the allocations.

Switch it to the generic version that does exactly the same thing for the
kernel page tables and adds __GFP_ACCOUNT for the user PTEs.

The pte_free() and pte_free_kernel() versions are identical to the generic
ones and can be simply dropped.

Link: http://lkml.kernel.org/r/1557296232-15361-14-git-send-email-rppt@linux.ibm.com
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Reviewed-by: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Acked-by: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Greentime Hu <green.hu@gmail.com>
Cc: Guan Xuetao <gxt@pku.edu.cn>
Cc: Guo Ren <guoren@kernel.org>
Cc: Guo Ren <ren_guo@c-sky.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Ley Foon Tan <lftan@altera.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Palmer Dabbelt <palmer@sifive.com>
Cc: Paul Burton <paul.burton@mips.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Richard Kuo <rkuo@codeaurora.org>
Cc: Richard Weinberger <richard@nod.at>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Sam Creasey <sammy@sammy.net>
Cc: Vincent Chen <deanbo422@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Replace $(src) and $(obj) with $(srctree) and $(objtree), respectively.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

Pull force_sig() argument change from Eric Biederman:
 "A source of error over the years has been that force_sig has taken a
  task parameter when it is only safe to use force_sig with the current
  task.

  The force_sig function is built for delivering synchronous signals
  such as SIGSEGV where the userspace application caused a synchronous
  fault (such as a page fault) and the kernel responded with a signal.

  Because the name force_sig does not make this clear, and because the
  force_sig takes a task parameter the function force_sig has been
  abused for sending other kinds of signals over the years. Slowly those
  have been fixed when the oopses have been tracked down.

  This set of changes fixes the remaining abusers of force_sig and
  carefully rips out the task parameter from force_sig and friends
  making this kind of error almost impossible in the future"

* 'siginfo-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (27 commits)
  signal/x86: Move tsk inside of CONFIG_MEMORY_FAILURE in do_sigbus
  signal: Remove the signal number and task parameters from force_sig_info
  signal: Factor force_sig_info_to_task out of force_sig_info
  signal: Generate the siginfo in force_sig
  signal: Move the computation of force into send_signal and correct it.
  signal: Properly set TRACE_SIGNAL_LOSE_INFO in __send_signal
  signal: Remove the task parameter from force_sig_fault
  signal: Use force_sig_fault_to_task for the two calls that don't deliver to current
  signal: Explicitly call force_sig_fault on current
  signal/unicore32: Remove tsk parameter from __do_user_fault
  signal/arm: Remove tsk parameter from __do_user_fault
  signal/arm: Remove tsk parameter from ptrace_break
  signal/nds32: Remove tsk parameter from send_sigtrap
  signal/riscv: Remove tsk parameter from do_trap
  signal/sh: Remove tsk parameter from force_sig_info_fault
  signal/um: Remove task parameter from send_sigtrap
  signal/x86: Remove task parameter from send_sigtrap
  signal: Remove task parameter from force_sig_mceerr
  signal: Remove task parameter from force_sig
  signal: Remove task parameter from force_sigsegv
  ...

When CONFIG_UML_TIME_TRAVEL_SUPPORT isn't set, the build was broken.
Fix this.

Fixes: 065038706f77 ("um: Support time travel mode")
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Richard Weinberger <richard@nod.at>

Kcov fails to start when compiled with kcov. Disable KCOV on
arch/uml/kernel/skas.

  $ gdb -q -ex r ./vmlinux
  Program received signal SIGSEGV, Segmentation fault.
  check_kcov_mode (t=<>, needed_mode=<>) at kernel/kcov.c:70
  70		mode = READ_ONCE(t->kcov_mode);

Signed-off-by: Marek Majkowski <marek@cloudflare.com>
Signed-off-by: Richard Weinberger <richard@nod.at>

Remove the CONFIG_UEVENT_HELPER_PATH because:
1. It is disabled since commit 1be01d4a5714 ("driver: base: Disable
   CONFIG_UEVENT_HELPER by default") as its dependency (UEVENT_HELPER) was
   made default to 'n',
2. It is not recommended (help message: "This should not be used today
   [...] creates a high system load") and was kept only for ancient
   userland,
3. Certain userland specifically requests it to be disabled (systemd
   README: "Legacy hotplug slows down the system and confuses udev").

Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Acked-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Richard Weinberger <richard@nod.at>

Sometimes it can be useful to run with "time travel" inside the
UML instance, for example for testing. For example, some tests
for the wireless subsystem and userspace are based on hwsim, a
virtual wireless adapter. Some tests can take a long time to
run because they e.g. wait for 120 seconds to elapse for some
regulatory checks. This obviously goes faster if it need not
actually wait that long, but time inside the test environment
just "bumps up" when there's nothing to do.

Add CONFIG_UML_TIME_TRAVEL_SUPPORT to enable code to support
such modes at runtime, selected on the command line:
 * just "time-travel", in which time inside the UML instance
   can move faster than real time, if there's nothing to do
 * "time-travel=inf-cpu" in which time also moves slower and
   any CPU processing takes no time at all, which allows to
   implement consistent behaviour regardless of host CPU load
   (or speed) or debug overhead.

An additional "time-travel-start=<seconds>" parameter is also
supported in this case to start the wall clock at this time
(in unix epoch).

With this enabled, the test mentioned above goes from a runtime
of about 140 seconds (with startup overhead and all) to being
CPU bound and finishing in 15 seconds (on my slow laptop).

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Richard Weinberger <richard@nod.at>