Attempt VMA lock-based page fault handling first, and fall back
to the existing mmap_lock-based handling if that fails.
Signed-off-by: Kefeng Wang <wangkefeng.wang@xxxxxxxxxx>
---
arch/arm/Kconfig | 1 +
arch/arm/mm/fault.c | 15 ++++++++++++++-
2 files changed, 15 insertions(+), 1 deletion(-)
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 1a6a6eb48a15..8b6d4507ccee 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -34,6 +34,7 @@ config ARM
select ARCH_OPTIONAL_KERNEL_RWX_DEFAULT if CPU_V7
select ARCH_SUPPORTS_ATOMIC_RMW
select ARCH_SUPPORTS_HUGETLBFS if ARM_LPAE
+ select ARCH_SUPPORTS_PER_VMA_LOCK
select ARCH_USE_BUILTIN_BSWAP
select ARCH_USE_CMPXCHG_LOCKREF
select ARCH_USE_MEMTEST
diff --git a/arch/arm/mm/fault.c b/arch/arm/mm/fault.c
index fef62e4a9edd..c44b83841e36 100644
--- a/arch/arm/mm/fault.c
+++ b/arch/arm/mm/fault.c
@@ -244,6 +244,7 @@ do_page_fault(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
vm_fault_t fault;
unsigned int flags = FAULT_FLAG_DEFAULT;
unsigned long vm_flags = VM_ACCESS_FLAGS;
+ struct vm_locked_fault vmlf;
if (kprobe_page_fault(regs, fsr))
return 0;
@@ -278,6 +279,18 @@ do_page_fault(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, addr);
+ VM_LOCKED_FAULT_INIT(vmlf, mm, addr, flags, vm_flags, regs, fsr);
+ if (try_vma_locked_page_fault(&vmlf, &fault))
+ goto retry;
+ else if (!(fault | VM_FAULT_RETRY))
+ goto done;
+
+ if (fault_signal_pending(fault, regs)) {
+ if (!user_mode(regs))
+ goto no_context;
+ return 0;
+ }
+
retry:
vma = lock_mm_and_find_vma(mm, addr, regs);
if (unlikely(!vma)) {
@@ -316,7 +329,7 @@ do_page_fault(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
}
mmap_read_unlock(mm);
-
+done:
/*
* Handle the "normal" case first - VM_FAULT_MAJOR
*/
--
2.27.0
