[PATCH 2/4] ARM: mm: Provide is_write_fault()

From: Kefeng Wang
Date: Wed Aug 25 2021 - 05:17:28 EST


The function will check whether the fault is caused by a write access.

Signed-off-by: Kefeng Wang <wangkefeng.wang@xxxxxxxxxx>
---
arch/arm/mm/fault.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/arch/arm/mm/fault.c b/arch/arm/mm/fault.c
index bc8779d54a64..f7ab6dabe89f 100644
--- a/arch/arm/mm/fault.c
+++ b/arch/arm/mm/fault.c
@@ -207,6 +207,11 @@ static inline bool is_permission_fault(unsigned int fsr)
return false;
}

+static inline bool is_write_fault(unsigned int fsr)
+{
+ return (fsr & FSR_WRITE) && !(fsr & FSR_CM);
+}
+
static vm_fault_t __kprobes
__do_page_fault(struct mm_struct *mm, unsigned long addr, unsigned int flags,
unsigned long vma_flags, struct pt_regs *regs)
@@ -261,7 +266,7 @@ do_page_fault(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
if (user_mode(regs))
flags |= FAULT_FLAG_USER;

- if ((fsr & FSR_WRITE) && !(fsr & FSR_CM)) {
+ if (is_write_fault(fsr)) {
flags |= FAULT_FLAG_WRITE;
vm_flags = VM_WRITE;
}
--
2.26.2