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authorVineet Gupta <vgupta@synopsys.com>2019-05-14 14:25:54 -0700
committerVineet Gupta <vgupta@synopsys.com>2019-07-01 11:02:22 -0700
commit85c5e33763a731967ca59085ffe6e694f872d38e (patch)
tree76abf68dd64252615a39fe966bd574ae04159803
parent13e2cc1240eb14d1a08b2c32f88b25bf20210ebc (diff)
ARC: mm: do_page_fault refactor #3: tidyup vma access permission code
The coding pattern to NOT intialize variables at declaration time but rather near code which makes us eof them makes it much easier to grok the overall logic, specially when the init is not simply 0 or 1 Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
-rw-r--r--arch/arc/mm/fault.c39
1 files changed, 21 insertions, 18 deletions
diff --git a/arch/arc/mm/fault.c b/arch/arc/mm/fault.c
index a3a292c58e50..8c7c81ce7f6a 100644
--- a/arch/arc/mm/fault.c
+++ b/arch/arc/mm/fault.c
@@ -64,9 +64,9 @@ void do_page_fault(unsigned long address, struct pt_regs *regs)
struct task_struct *tsk = current;
struct mm_struct *mm = tsk->mm;
int si_code = SEGV_MAPERR;
+ unsigned int write = 0, exec = 0, mask;
vm_fault_t fault;
- int write = regs->ecr_cause & ECR_C_PROTV_STORE; /* ST/EX */
- unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE;
+ unsigned int flags;
/*
* NOTE! We MUST NOT take any locks for this case. We may
@@ -88,8 +88,18 @@ void do_page_fault(unsigned long address, struct pt_regs *regs)
if (faulthandler_disabled() || !mm)
goto no_context;
+ if (regs->ecr_cause & ECR_C_PROTV_STORE) /* ST/EX */
+ write = 1;
+ else if ((regs->ecr_vec == ECR_V_PROTV) &&
+ (regs->ecr_cause == ECR_C_PROTV_INST_FETCH))
+ exec = 1;
+
+ flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE;
if (user_mode(regs))
flags |= FAULT_FLAG_USER;
+ if (write)
+ flags |= FAULT_FLAG_WRITE;
+
retry:
down_read(&mm->mmap_sem);
@@ -102,24 +112,17 @@ retry:
}
/*
- * Ok, we have a good vm_area for this memory access, so
- * we can handle it..
+ * vm_area is good, now check permissions for this memory access
*/
- si_code = SEGV_ACCERR;
-
- /* Handle protection violation, execute on heap or stack */
-
- if ((regs->ecr_vec == ECR_V_PROTV) &&
- (regs->ecr_cause == ECR_C_PROTV_INST_FETCH))
+ mask = VM_READ;
+ if (write)
+ mask = VM_WRITE;
+ if (exec)
+ mask = VM_EXEC;
+
+ if (!(vma->vm_flags & mask)) {
+ si_code = SEGV_ACCERR;
goto bad_area;
-
- if (write) {
- if (!(vma->vm_flags & VM_WRITE))
- goto bad_area;
- flags |= FAULT_FLAG_WRITE;
- } else {
- if (!(vma->vm_flags & (VM_READ | VM_EXEC)))
- goto bad_area;
}
/*