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

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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>
This commit is contained in:
Linus Torvalds
2023-06-24 10:55:38 -07:00
parent 8b35ca3e45
commit a050ba1e74
18 changed files with 45 additions and 124 deletions
Download Patch File Download Diff File Expand all files Collapse all files

1
arch/sparc/Kconfig
View File

@@ -57,6 +57,7 @@ config SPARC32
select DMA_DIRECT_REMAP
select GENERIC_ATOMIC64
select HAVE_UID16
select LOCK_MM_AND_FIND_VMA
select OLD_SIGACTION
select ZONE_DMA

32
arch/sparc/mm/fault_32.c
View File

@@ -143,28 +143,19 @@ asmlinkage void do_sparc_fault(struct pt_regs *regs, int text_fault, int write,
if (pagefault_disabled() || !mm)
goto no_context;
if (!from_user && address >= PAGE_OFFSET)
goto no_context;
perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address);
retry:
mmap_read_lock(mm);
if (!from_user && address >= PAGE_OFFSET)
goto bad_area;
vma = find_vma(mm, address);
vma = lock_mm_and_find_vma(mm, address, regs);
if (!vma)
goto bad_area;
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;
goto bad_area_nosemaphore;
/*
* Ok, we have a good vm_area for this memory access, so
* we can handle it..
*/
good_area:
code = SEGV_ACCERR;
if (write) {
if (!(vma->vm_flags & VM_WRITE))
@@ -321,17 +312,9 @@ static void force_user_fault(unsigned long address, int write)
code = SEGV_MAPERR;
mmap_read_lock(mm);
vma = find_vma(mm, address);
vma = lock_mm_and_find_vma(mm, address, regs);
if (!vma)
goto bad_area;
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:
goto bad_area_nosemaphore;
code = SEGV_ACCERR;
if (write) {
if (!(vma->vm_flags & VM_WRITE))
@@ -350,6 +333,7 @@ good_area:
return;
bad_area:
mmap_read_unlock(mm);
bad_area_nosemaphore:
__do_fault_siginfo(code, SIGSEGV, tsk->thread.kregs, address);
return;