commit e10e2f58030c5c211d49042a8c2a1b93d40b2ffb upstream.

In the event that random_get_entropy() can't access a cycle counter or
similar, falling back to returning 0 is really not the best we can do.
Instead, at least calling random_get_entropy_fallback() would be
preferable, because that always needs to return _something_, even
falling back to jiffies eventually. It's not as though
random_get_entropy_fallback() is super high precision or guaranteed to
be entropic, but basically anything that's not zero all the time is
better than returning zero all the time.

This is accomplished by just including the asm-generic code like on
other architectures, which means we can get rid of the empty stub
function here.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Arnd Bergmann <arnd@arndb.de>
Acked-by: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Fast coprocessor exception handler saves a3..a6, but coprocessor context
load/store code uses a4..a7 as temporaries, potentially clobbering a7.
'Potentially' because coprocessor state load/store macros may not use
all four temporary registers (and neither FPU nor HiFi macros do).
Use a3..a6 as intended.

Cc: stable@vger.kernel.org
Fixes: c658eac628aa ("[XTENSA] Add support for configurable registers and coprocessors")
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>

There is a deadlock in rs_close(), which is shown
below:

   (Thread 1)              |      (Thread 2)
                           | rs_open()
rs_close()                 |  mod_timer()
 spin_lock_bh() //(1)      |  (wait a time)
 ...                       | rs_poll()
 del_timer_sync()          |  spin_lock() //(2)
 (wait timer to stop)      |  ...

We hold timer_lock in position (1) of thread 1 and
use del_timer_sync() to wait timer to stop, but timer handler
also need timer_lock in position (2) of thread 2.
As a result, rs_close() will block forever.

This patch deletes the redundant timer_lock in order to
prevent the deadlock. Because there is no race condition
between rs_close, rs_open and rs_poll.

Signed-off-by: Duoming Zhou <duoming@zju.edu.cn>
Message-Id: <20220407154430.22387-1-duoming@zju.edu.cn>
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>

These patch_text implementations are using stop_machine_cpuslocked
infrastructure with atomic cpu_count. The original idea: When the
master CPU patch_text, the others should wait for it. But current
implementation is using the first CPU as master, which couldn't
guarantee the remaining CPUs are waiting. This patch changes the
last CPU as the master to solve the potential risk.

Fixes: 64711f9a47d4 ("xtensa: implement jump_label support")
Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Signed-off-by: Guo Ren <guoren@kernel.org>
Reviewed-by: Max Filippov <jcmvbkbc@gmail.com>
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: <stable@vger.kernel.org>
Message-Id: <20220407073323.743224-4-guoren@kernel.org>
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>

Pull Kbuild updates from Masahiro Yamada:

 - Add new environment variables, USERCFLAGS and USERLDFLAGS to allow
   additional flags to be passed to user-space programs.

 - Fix missing fflush() bugs in Kconfig and fixdep

 - Fix a minor bug in the comment format of the .config file

 - Make kallsyms ignore llvm's local labels, .L*

 - Fix UAPI compile-test for cross-compiling with Clang

 - Extend the LLVM= syntax to support LLVM=<suffix> form for using a
   particular version of LLVm, and LLVM=<prefix> form for using custom
   LLVM in a particular directory path.

 - Clean up Makefiles

* tag 'kbuild-v5.18-v2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
  kbuild: Make $(LLVM) more flexible
  kbuild: add --target to correctly cross-compile UAPI headers with Clang
  fixdep: use fflush() and ferror() to ensure successful write to files
  arch: syscalls: simplify uapi/kapi directory creation
  usr/include: replace extra-y with always-y
  certs: simplify empty certs creation in certs/Makefile
  certs: include certs/signing_key.x509 unconditionally
  kallsyms: ignore all local labels prefixed by '.L'
  kconfig: fix missing '# end of' for empty menu
  kconfig: add fflush() before ferror() check
  kbuild: replace $(if A,A,B) with $(or A,B)
  kbuild: Add environment variables for userprogs flags
  kbuild: unify cmd_copy and cmd_shipped

$(shell ...) expands to empty. There is no need to assign it to _dummy.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>

Pull dma-mapping updates from Christoph Hellwig:

 - do not zero buffer in set_memory_decrypted (Kirill A. Shutemov)

 - fix return value of dma-debug __setup handlers (Randy Dunlap)

 - swiotlb cleanups (Robin Murphy)

 - remove most remaining users of the pci-dma-compat.h API
   (Christophe JAILLET)

 - share the ABI header for the DMA map_benchmark with userspace
   (Tian Tao)

 - update the maintainer for DMA MAPPING BENCHMARK (Xiang Chen)

 - remove CONFIG_DMA_REMAP (me)

* tag 'dma-mapping-5.18' of git://git.infradead.org/users/hch/dma-mapping:
  dma-mapping: benchmark: extract a common header file for map_benchmark definition
  dma-debug: fix return value of __setup handlers
  dma-mapping: remove CONFIG_DMA_REMAP
  media: v4l2-pci-skeleton: Remove usage of the deprecated "pci-dma-compat.h" API
  rapidio/tsi721: Remove usage of the deprecated "pci-dma-compat.h" API
  sparc: Remove usage of the deprecated "pci-dma-compat.h" API
  agp/intel: Remove usage of the deprecated "pci-dma-compat.h" API
  alpha: Remove usage of the deprecated "pci-dma-compat.h" API
  MAINTAINERS: update maintainer list of DMA MAPPING BENCHMARK
  swiotlb: simplify array allocation
  swiotlb: tidy up includes
  swiotlb: simplify debugfs setup
  swiotlb: do not zero buffer in set_memory_decrypted()

Pull ptrace cleanups from Eric Biederman:
 "This set of changes removes tracehook.h, moves modification of all of
  the ptrace fields inside of siglock to remove races, adds a missing
  permission check to ptrace.c

  The removal of tracehook.h is quite significant as it has been a major
  source of confusion in recent years. Much of that confusion was around
  task_work and TIF_NOTIFY_SIGNAL (which I have now decoupled making the
  semantics clearer).

  For people who don't know tracehook.h is a vestiage of an attempt to
  implement uprobes like functionality that was never fully merged, and
  was later superseeded by uprobes when uprobes was merged. For many
  years now we have been removing what tracehook functionaly a little
  bit at a time. To the point where anything left in tracehook.h was
  some weird strange thing that was difficult to understand"

* tag 'ptrace-cleanups-for-v5.18' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace:
  ptrace: Remove duplicated include in ptrace.c
  ptrace: Check PTRACE_O_SUSPEND_SECCOMP permission on PTRACE_SEIZE
  ptrace: Return the signal to continue with from ptrace_stop
  ptrace: Move setting/clearing ptrace_message into ptrace_stop
  tracehook: Remove tracehook.h
  resume_user_mode: Move to resume_user_mode.h
  resume_user_mode: Remove #ifdef TIF_NOTIFY_RESUME in set_notify_resume
  signal: Move set_notify_signal and clear_notify_signal into sched/signal.h
  task_work: Decouple TIF_NOTIFY_SIGNAL and task_work
  task_work: Call tracehook_notify_signal from get_signal on all architectures
  task_work: Introduce task_work_pending
  task_work: Remove unnecessary include from posix_timers.h
  ptrace: Remove tracehook_signal_handler
  ptrace: Remove arch_syscall_{enter,exit}_tracehook
  ptrace: Create ptrace_report_syscall_{entry,exit} in ptrace.h
  ptrace/arm: Rename tracehook_report_syscall report_syscall
  ptrace: Move ptrace_report_syscall into ptrace.h

Pull tty/serial driver updates from Greg KH:
 "Here are the big set of tty and serial driver changes for 5.18-rc1.

  Nothing major, some more good cleanups from Jiri and 2 new serial
  drivers. Highlights include:

   - termbits cleanups

   - export symbol cleanups and other core cleanups from Jiri Slaby

   - new sunplus and mvebu uart drivers (amazing that people are still
     creating new uarts...)

   - samsung serial driver cleanups

   - ldisc 29 is now "reserved" for experimental/development line
     disciplines

   - lots of other tiny fixes and cleanups to serial drivers and
     bindings

  All of these have been in linux-next for a while with no reported
  issues"

* tag 'tty-5.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (104 commits)
  vt_ioctl: fix potential spectre v1 in VT_DISALLOCATE
  serial: 8250: fix XOFF/XON sending when DMA is used
  tty: serial: samsung: Add ARTPEC-8 support
  dt-bindings: serial: samsung: Add ARTPEC-8 UART
  serial: sc16is7xx: Clear RS485 bits in the shutdown
  tty: serial: samsung: simplify getting OF match data
  tty: serial: samsung: constify variables and pointers
  tty: serial: samsung: constify s3c24xx_serial_drv_data members
  tty: serial: samsung: constify UART name
  tty: serial: samsung: constify s3c24xx_serial_drv_data
  tty: serial: samsung: reduce number of casts
  tty: serial: samsung: embed s3c2410_uartcfg in parent structure
  tty: serial: samsung: embed s3c24xx_uart_info in parent structure
  serial: 8250_tegra: mark acpi_device_id as unused with !ACPI
  tty: serial: bcm63xx: use more precise Kconfig symbol
  serial: SERIAL_SUNPLUS should depend on ARCH_SUNPLUS
  tty: serial: jsm: fix two assignments in if conditions
  tty: serial: jsm: remove redundant assignments to variable linestatus
  serial: 8250_mtk: make two read-only arrays static const
  serial: samsung_tty: do not unlock port->lock for uart_write_wakeup()
  ...

Pull char/misc and other driver updates from Greg KH:
 "Here is the big set of char/misc and other small driver subsystem
  updates for 5.18-rc1.

  Included in here are merges from driver subsystems which contain:

   - iio driver updates and new drivers

   - fsi driver updates

   - fpga driver updates

   - habanalabs driver updates and support for new hardware

   - soundwire driver updates and new drivers

   - phy driver updates and new drivers

   - coresight driver updates

   - icc driver updates

  Individual changes include:

   - mei driver updates

   - interconnect driver updates

   - new PECI driver subsystem added

   - vmci driver updates

   - lots of tiny misc/char driver updates

  All of these have been in linux-next for a while with no reported
  problems"

* tag 'char-misc-5.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: (556 commits)
  firmware: google: Properly state IOMEM dependency
  kgdbts: fix return value of __setup handler
  firmware: sysfb: fix platform-device leak in error path
  firmware: stratix10-svc: add missing callback parameter on RSU
  arm64: dts: qcom: add non-secure domain property to fastrpc nodes
  misc: fastrpc: Add dma handle implementation
  misc: fastrpc: Add fdlist implementation
  misc: fastrpc: Add helper function to get list and page
  misc: fastrpc: Add support to secure memory map
  dt-bindings: misc: add fastrpc domain vmid property
  misc: fastrpc: check before loading process to the DSP
  misc: fastrpc: add secure domain support
  dt-bindings: misc: add property to support non-secure DSP
  misc: fastrpc: Add support to get DSP capabilities
  misc: fastrpc: add support for FASTRPC_IOCTL_MEM_MAP/UNMAP
  misc: fastrpc: separate fastrpc device from channel context
  dt-bindings: nvmem: brcm,nvram: add basic NVMEM cells
  dt-bindings: nvmem: make "reg" property optional
  nvmem: brcm_nvram: parse NVRAM content into NVMEM cells
  nvmem: dt-bindings: Fix the error of dt-bindings check
  ...