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arm64/mm: Convert to using lock_mm_and_find_vma()

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commit ae870a68b5 upstream.

This converts arm64 to use the new page fault helper.  It was very
straightforward, but still needed a fix for the "obvious" conversion I
initially did.  Thanks to Suren for the fix and testing.

Fixed-and-tested-by: Suren Baghdasaryan <surenb@google.com>
Unnecessary-code-removal-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[6.1: Ignore CONFIG_PER_VMA_LOCK context]
Signed-off-by: Samuel Mendoza-Jonas <samjonas@amazon.com>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Linus Torvalds
2023-06-15 17:11:44 -07:00
committed by Greg Kroah-Hartman
parent 755aa1bc6a
commit b92cd80e5f
2 changed files with 10 additions and 37 deletions
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1
arch/arm64/Kconfig
View File

@@ -211,6 +211,7 @@ config ARM64
select IRQ_DOMAIN select IRQ_DOMAIN
select IRQ_FORCED_THREADING select IRQ_FORCED_THREADING
select KASAN_VMALLOC if KASAN select KASAN_VMALLOC if KASAN
select LOCK_MM_AND_FIND_VMA
select MODULES_USE_ELF_RELA select MODULES_USE_ELF_RELA
select NEED_DMA_MAP_STATE select NEED_DMA_MAP_STATE
select NEED_SG_DMA_LENGTH select NEED_SG_DMA_LENGTH

46
arch/arm64/mm/fault.c
View File

@@ -483,27 +483,14 @@ static void do_bad_area(unsigned long far, unsigned long esr,
#define VM_FAULT_BADMAP ((__force vm_fault_t)0x010000) #define VM_FAULT_BADMAP ((__force vm_fault_t)0x010000)
#define VM_FAULT_BADACCESS ((__force vm_fault_t)0x020000) #define VM_FAULT_BADACCESS ((__force vm_fault_t)0x020000)
static vm_fault_t __do_page_fault(struct mm_struct *mm, unsigned long addr, static vm_fault_t __do_page_fault(struct mm_struct *mm,
struct vm_area_struct *vma, unsigned long addr,
unsigned int mm_flags, unsigned long vm_flags, unsigned int mm_flags, unsigned long vm_flags,
struct pt_regs *regs) struct pt_regs *regs)
{ {
struct vm_area_struct *vma = find_vma(mm, addr);
if (unlikely(!vma))
return VM_FAULT_BADMAP;
/* /*
* Ok, we have a good vm_area for this memory access, so we can handle * Ok, we have a good vm_area for this memory access, so we can handle
* it. * it.
*/
if (unlikely(vma->vm_start > addr)) {
if (!(vma->vm_flags & VM_GROWSDOWN))
return VM_FAULT_BADMAP;
if (expand_stack(vma, addr))
return VM_FAULT_BADMAP;
}
/*
* Check that the permissions on the VMA allow for the fault which * Check that the permissions on the VMA allow for the fault which
* occurred. * occurred.
*/ */
@@ -535,6 +522,7 @@ static int __kprobes do_page_fault(unsigned long far, unsigned long esr,
unsigned long vm_flags; unsigned long vm_flags;
unsigned int mm_flags = FAULT_FLAG_DEFAULT; unsigned int mm_flags = FAULT_FLAG_DEFAULT;
unsigned long addr = untagged_addr(far); unsigned long addr = untagged_addr(far);
struct vm_area_struct *vma;
if (kprobe_page_fault(regs, esr)) if (kprobe_page_fault(regs, esr))
return 0; return 0;
@@ -585,31 +573,14 @@ static int __kprobes do_page_fault(unsigned long far, unsigned long esr,
perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, addr); perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, addr);
/*
* As per x86, we may deadlock here. However, since the kernel only
* validly references user space from well defined areas of the code,
* we can bug out early if this is from code which shouldn't.
*/
if (!mmap_read_trylock(mm)) {
if (!user_mode(regs) && !search_exception_tables(regs->pc))
goto no_context;
retry: retry:
mmap_read_lock(mm); vma = lock_mm_and_find_vma(mm, addr, regs);
} else { if (unlikely(!vma)) {
/* fault = VM_FAULT_BADMAP;
* The above mmap_read_trylock() might have succeeded in which goto done;
* case, we'll have missed the might_sleep() from down_read().
*/
might_sleep();
#ifdef CONFIG_DEBUG_VM
if (!user_mode(regs) && !search_exception_tables(regs->pc)) {
mmap_read_unlock(mm);
goto no_context;
}
#endif
} }
fault = __do_page_fault(mm, addr, mm_flags, vm_flags, regs); fault = __do_page_fault(mm, vma, addr, mm_flags, vm_flags, regs);
/* Quick path to respond to signals */ /* Quick path to respond to signals */
if (fault_signal_pending(fault, regs)) { if (fault_signal_pending(fault, regs)) {
@@ -628,6 +599,7 @@ retry:
} }
mmap_read_unlock(mm); mmap_read_unlock(mm);
done:
/* /*
* Handle the "normal" (no error) case first. * Handle the "normal" (no error) case first.
*/ */