commit a050ba1e7422f2cc60ff8bfde3f96d34d00cb585 upstream.

This does the simple pattern conversion of alpha, arc, csky, hexagon,
loongarch, nios2, sh, sparc32, and xtensa to the lock_mm_and_find_vma()
helper.  They all have the regular fault handling pattern without odd
special cases.

The remaining architectures all have something that keeps us from a
straightforward conversion: ia64 and parisc have stacks that can grow
both up as well as down (and ia64 has special address region checks).

And m68k, microblaze, openrisc, sparc64, and um end up having extra
rules about only expanding the stack down a limited amount below the
user space stack pointer.  That is something that x86 used to do too
(long long ago), and it probably could just be skipped, but it still
makes the conversion less than trivial.

Note that this conversion was done manually and with the exception of
alpha without any build testing, because I have a fairly limited cross-
building environment.  The cases are all simple, and I went through the
changes several times, but...

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Looks like a braino that used to be fixed in e.g. #next.alpha
had gotten into alpha.git cherry-picked version of that patch.

Sure, alpha has no preempt, but preempt_enable() in place of
preempt_disable() is actively confusing the readers...

Other than that, the cherry-picked variant matches what I have.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Pull VM_FAULT_RETRY fixes from Al Viro:
 "Some of the page fault handlers do not deal with the following case
  correctly:

   - handle_mm_fault() has returned VM_FAULT_RETRY

   - there is a pending fatal signal

   - fault had happened in kernel mode

  Correct action in such case is not "return unconditionally" - fatal
  signals are handled only upon return to userland and something like
  copy_to_user() would end up retrying the faulting instruction and
  triggering the same fault again and again.

  What we need to do in such case is to make the caller to treat that as
  failed uaccess attempt - handle exception if there is an exception
  handler for faulting instruction or oops if there isn't one.

  Over the years some architectures had been fixed and now are handling
  that case properly; some still do not. This series should fix the
  remaining ones.

  Status:

   - m68k, riscv, hexagon, parisc: tested/acked by maintainers.

   - alpha, sparc32, sparc64: tested locally - bug has been reproduced
     on the unpatched kernel and verified to be fixed by this series.

   - ia64, microblaze, nios2, openrisc: build, but otherwise completely
     untested"

* tag 'pull-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  openrisc: fix livelock in uaccess
  nios2: fix livelock in uaccess
  microblaze: fix livelock in uaccess
  ia64: fix livelock in uaccess
  sparc: fix livelock in uaccess
  alpha: fix livelock in uaccess
  parisc: fix livelock in uaccess
  hexagon: fix livelock in uaccess
  riscv: fix livelock in uaccess
  m68k: fix livelock in uaccess

alpha equivalent of 26178ec11ef3 "x86: mm: consolidate VM_FAULT_RETRY handling"
If e.g. get_user() triggers a page fault and a fatal signal is caught, we might
end up with handle_mm_fault() returning VM_FAULT_RETRY and not doing anything
to page tables.  In such case we must *not* return to the faulting insn -
that would repeat the entire thing without making any progress; what we need
instead is to treat that as failed (user) memory access.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Pull alpha updates from Al Viro:
 "Mostly small janitorial fixes but there's also more important ones: a
  patch to fix loading large modules from Edward Humes, and some fixes
  from Al Viro"

[ The fixes from Al mostly came in separately through Al's trees too and
  are now duplicated..   - Linus ]

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mattst88/alpha:
  alpha: in_irq() cleanup
  alpha: lazy FPU switching
  alpha/boot/misc: trim unused declarations
  alpha/boot/tools/objstrip: fix the check for ELF header
  alpha/boot: fix the breakage from -isystem series...
  alpha: fix FEN fault handling
  alpha: Avoid comma separated statements
  alpha: fixed a typo in core_cia.c
  alpha: remove unused __SLOW_DOWN_IO and SLOW_DOWN_IO definitions
  alpha: update config files
  alpha: fix R_ALPHA_LITERAL reloc for large modules
  alpha: Add some spaces to ensure format specification
  alpha: replace NR_SYSCALLS by NR_syscalls
  alpha: Remove redundant local asm header redirections
  alpha: Implement "current_stack_pointer"
  alpha: remove redundant err variable
  alpha: osf_sys: reduce kernel log spamming on invalid osf_mount call typenr

Replace the obsolete and ambiguos macro in_irq() with new
macro in_hardirq().

Signed-off-by: Changbin Du <changbin.du@gmail.com>
Signed-off-by: Matt Turner <mattst88@gmail.com>

	On each context switch we save the FPU registers on stack
of old process and restore FPU registers from the stack of new one.
That allows us to avoid doing that each time we enter/leave the
kernel mode; however, that can get suboptimal in some cases.

	For one thing, we don't need to bother saving anything
for kernel threads.  For another, if between entering and leaving
the kernel a thread gives CPU up more than once, it will do
useless work, saving the same values every time, only to discard
the saved copy as soon as it returns from switch_to().

	Alternative solution:

* move the array we save into from switch_stack to thread_info
* have a (thread-synchronous) flag set when we save them
* have another flag set when they should be restored on return to userland.
* do *NOT* save/restore them in do_switch_stack()/undo_switch_stack().
* restore on the exit to user mode if the restore flag had
been set.  Clear both flags.
* on context switch, entry to fork/clone/vfork, before entry into do_signal()
and on entry into straced syscall save the registers and set the 'saved' flag
unless it had been already set.
* on context switch set the 'restore' flag as well.
* have copy_thread() set both flags for child, so the registers would be
restored once the child returns to userland.
* use the saved data in setup_sigcontext(); have restore_sigcontext() set both flags
and copy from sigframe to save area.
* teach ptrace to look for FPU registers in thread_info instead of
switch_stack.
* teach isolated accesses to FPU registers (rdfpcr, wrfpcr, etc.)
to check the 'saved' flag (under preempt_disable()) and work with the save area
if it's been set; if 'saved' flag is found upon write access, set 'restore' flag
as well.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Matt Turner <mattst88@gmail.com>

gzip_mark() and gzip_release() are gone; there used to be two
forward declarations of each and the patch removing those suckers
had left one of each behind...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Matt Turner <mattst88@gmail.com>

Just memcmp() with ELFMAG - that's the normal way to do it in userland
code, which that thing is.  Besides, that has the benefit of actually
building - str_has_prefix() is *NOT* present in <string.h>.

Fixes: 5f14596e55de "alpha: Replace strncmp with str_has_prefix"
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Matt Turner <mattst88@gmail.com>

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Matt Turner <mattst88@gmail.com>