This merges the bad_area(), bad_area_access_error() and the underlying
__bad_area() functions into one single unified function.
Passing a NULL vma triggers the prior bad_area() behavior, while
passing a non-NULL vma triggers the prior bad_area_access_error() behavior.
The control flow is very similar in all cases, and we now release the
mmap_sem read lock in one single place rather than 3.
Text size is reduced by 356 bytes here.
Signed-off-by: Michel Lespinasse <walken@xxxxxxxxxx>
---
arch/x86/mm/fault.c | 54 ++++++++++++++++++++-------------------------
1 file changed, 24 insertions(+), 30 deletions(-)
diff --git arch/x86/mm/fault.c arch/x86/mm/fault.c
index a8ce9e160b72..adbd2b03fcf9 100644
--- arch/x86/mm/fault.c
+++ arch/x86/mm/fault.c
@@ -919,26 +919,6 @@ bad_area_nosemaphore(struct pt_regs *regs, unsigned long error_code,
__bad_area_nosemaphore(regs, error_code, address, 0, SEGV_MAPERR);
}
-static void
-__bad_area(struct pt_regs *regs, unsigned long error_code,
- unsigned long address, u32 pkey, int si_code)
-{
- struct mm_struct *mm = current->mm;
- /*
- * Something tried to access memory that isn't in our memory map..
- * Fix it, but check if it's kernel or user first..
- */
- mm_read_unlock(mm);
-
- __bad_area_nosemaphore(regs, error_code, address, pkey, si_code);
-}
-
-static noinline void
-bad_area(struct pt_regs *regs, unsigned long error_code, unsigned long address)
-{
- __bad_area(regs, error_code, address, 0, SEGV_MAPERR);
-}
-
static inline bool bad_area_access_from_pkeys(unsigned long error_code,
struct vm_area_struct *vma)
{
@@ -957,9 +937,15 @@ static inline bool bad_area_access_from_pkeys(unsigned long error_code,
}
static noinline void
-bad_area_access_error(struct pt_regs *regs, unsigned long error_code,
- unsigned long address, struct vm_area_struct *vma)
+bad_area(struct pt_regs *regs, unsigned long error_code,
+ unsigned long address, struct vm_area_struct *vma)
{
+ u32 pkey = 0;
+ int si_code = SEGV_MAPERR;
+
+ if (!vma)
+ goto unlock;
+
/*
* This OSPKE check is not strictly necessary at runtime.
* But, doing it this way allows compiler optimizations
@@ -986,12 +972,20 @@ bad_area_access_error(struct pt_regs *regs, unsigned long error_code,
* 6. T1 : reaches here, sees vma_pkey(vma)=5, when we really
* faulted on a pte with its pkey=4.
*/
- u32 pkey = vma_pkey(vma);
-
- __bad_area(regs, error_code, address, pkey, SEGV_PKUERR);
+ pkey = vma_pkey(vma);
+ si_code = SEGV_PKUERR;
} else {
- __bad_area(regs, error_code, address, 0, SEGV_ACCERR);
+ si_code = SEGV_ACCERR;
}
+
+unlock:
+ /*
+ * Something tried to access memory that isn't in our memory map..
+ * Fix it, but check if it's kernel or user first..
+ */
+ mm_read_unlock(current->mm);
+
+ __bad_area_nosemaphore(regs, error_code, address, pkey, si_code);
}
static void
@@ -1401,17 +1395,17 @@ void do_user_addr_fault(struct pt_regs *regs,
vma = find_vma(mm, address);
if (unlikely(!vma)) {
- bad_area(regs, hw_error_code, address);
+ bad_area(regs, hw_error_code, address, NULL);
return;
}
if (likely(vma->vm_start <= address))
goto good_area;
if (unlikely(!(vma->vm_flags & VM_GROWSDOWN))) {
- bad_area(regs, hw_error_code, address);
+ bad_area(regs, hw_error_code, address, NULL);
return;
}
if (unlikely(expand_stack(vma, address))) {
- bad_area(regs, hw_error_code, address);
+ bad_area(regs, hw_error_code, address, NULL);
return;
}
@@ -1421,7 +1415,7 @@ void do_user_addr_fault(struct pt_regs *regs,
*/
good_area:
if (unlikely(access_error(hw_error_code, vma))) {
- bad_area_access_error(regs, hw_error_code, address, vma);
+ bad_area(regs, hw_error_code, address, vma);
return;
}
--
2.25.0.341.g760bfbb309-goog
