mm/fault: convert remaining simple cases to lock_mm_and_find_vma()

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>

2 files changed, 5 insertions, 14 deletions

diff --git a/arch/hexagon/Kconfig b/arch/hexagon/Kconfig
index 54eadf265178..6726f4941015 100644
--- a/arch/hexagon/Kconfig
+++ b/arch/hexagon/Kconfig
@@ -28,6 +28,7 @@ config HEXAGON
 	select GENERIC_SMP_IDLE_THREAD
 	select STACKTRACE_SUPPORT
 	select GENERIC_CLOCKEVENTS_BROADCAST
+	select LOCK_MM_AND_FIND_VMA
 	select MODULES_USE_ELF_RELA
 	select GENERIC_CPU_DEVICES
 	select ARCH_WANT_LD_ORPHAN_WARN
diff --git a/arch/hexagon/mm/vm_fault.c b/arch/hexagon/mm/vm_fault.c
index 4b578d02fd01..7295ea3f8cc8 100644
--- a/arch/hexagon/mm/vm_fault.c
+++ b/arch/hexagon/mm/vm_fault.c
@@ -57,21 +57,10 @@ void do_page_fault(unsigned long address, long cause, struct pt_regs *regs)
 
 	perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address);
 retry:
-	mmap_read_lock(mm);
-	vma = find_vma(mm, address);
-	if (!vma)
-		goto bad_area;
+	vma = lock_mm_and_find_vma(mm, address, regs);
+	if (unlikely(!vma))
+		goto bad_area_nosemaphore;
 
-	if (vma->vm_start <= address)
-		goto good_area;
-
-	if (!(vma->vm_flags & VM_GROWSDOWN))
-		goto bad_area;
-
-	if (expand_stack(vma, address))
-		goto bad_area;
-
-good_area:
 	/* Address space is OK.  Now check access rights. */
 	si_code = SEGV_ACCERR;
 
@@ -143,6 +132,7 @@ good_area:
 bad_area:
 	mmap_read_unlock(mm);
 
+bad_area_nosemaphore:
 	if (user_mode(regs)) {
 		force_sig_fault(SIGSEGV, si_code, (void __user *)address);
 		return;