Fix typos, most reported by "codespell arch/arc".  Only touches comments,
no code changes.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Vineet Gupta <vgupta@kernel.org>

| ../arch/arc/kernel/kprobes.c:193:15: warning: no previous prototype for 'arc_kprobe_handler' [-Wmissing-prototypes]
|  193 | int __kprobes arc_kprobe_handler(unsigned long addr, struct pt_regs *regs)
|
|../arch/arc/kernel/ptrace.c:342:16: warning: no previous prototype for 'syscall_trace_enter' [-Wmissing-prototypes]
|  342 | asmlinkage int syscall_trace_enter(struct pt_regs *regs)

Link: https://qa-reports.linaro.org/lkft/linux-next-master/build/next-20240325/testrun/23149630/suite/build/test/gcc-9-defconfig/log
Reported-by: Linux Kernel Functional Testing <lkft@linaro.org>
Signed-off-by: Vineet Gupta <vgupta@kernel.org>

There is no point in having seven architectures implementing the same empty
stub.

Provide a weak function in the init code and remove the stubs.

This also allows to utilize the function on UP which is required to
sanitize the per CPU handling on X86 UP.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20240304005104.567671691@linutronix.de

Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <error27@gmail.com>
Closes: https://lore.kernel.org/r/202311280906.VAIwEAfT-lkp@intel.com/
Signed-off-by: Vineet Gupta <vgupta@kernel.org>

Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202312082320.VDN5A9hb-lkp@intel.com/
Signed-off-by: Vineet Gupta <vgupta@kernel.org>

Overlayfs uses backing files with "fake" overlayfs f_path and "real"
underlying f_inode, in order to use underlying inode aops for mapped
files and to display the overlayfs path in /proc/<pid>/maps.

In preparation for storing the overlayfs "fake" path instead of the
underlying "real" path in struct backing_file, define a noop helper
file_user_path() that returns f_path for now.

Use the new helper in procfs and kernel logs whenever a path of a
mapped file is displayed to users.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Link: https://lore.kernel.org/r/20231009153712.1566422-3-amir73il@gmail.com
Signed-off-by: Christian Brauner <brauner@kernel.org>

Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202308221549.XKufWEWp-lkp@intel.com/
Signed-off-by: Vineet Gupta <vgupta@kernel.org>

Reduces duplication in each ISA specific pt_regs

Tested-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202308151342.ROQ9Urvv-lkp@intel.com
Signed-off-by: Vineet Gupta <vgupta@kernel.org>

Instead of r26,fp,sp,r12,r30 order as fp,r30,r12,r26,sp

 - keeps SP at well known position (right abive hardware autosave)
 - r26,r12 saved specifically for ARCv2 (and not in ARCv3) kept
   closer for easy ifdef'ry later

Signed-off-by: Vineet Gupta <vgupta@kernel.org>

THe high level structure of most ARC exception handlers is
 1. save regfile with EXCEPTION_PROLOGUE
 2. setup r0: EFA (not part of pt_regs)
 3. setup r1: pointer to pt_regs (SP)
 4. drop down to pure kernel mode (from exception)
 5. call the Linux "C" handler

Remove the boiler plate code by moving #2, #3, #4 into #1.

The exceptions to most exceptions are syscall Trap and Machine check
which don't do some of above for various reasons, so call a newly
introduced variant EXCEPTION_PROLOGUE_KEEP_AE (same as original
EXCEPTION_PROLOGUE)

Tested-by: Pavel Kozlov <Pavel.Kozlov@synopsys.com>
Signed-off-by: Vineet Gupta <vgupta@kernel.org>