The patch titled
Subject: arm: mm: drop VM_FAULT_BADMAP/VM_FAULT_BADACCESS
has been added to the -mm mm-unstable branch. Its filename is
arm-mm-drop-vm_fault_badmap-vm_fault_badaccess.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/arm-mm-drop-vm_fault_badmap-vm_fault_badaccess.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Kefeng Wang <wangkefeng.wang@xxxxxxxxxx>
Subject: arm: mm: drop VM_FAULT_BADMAP/VM_FAULT_BADACCESS
Date: Sun, 7 Apr 2024 16:12:11 +0800
If bad map or access, directly set si_code to SEGV_MAPRR or SEGV_ACCERR,
also set fault to 0 and goto error handling, which make us to drop the
arch's special vm fault reason.
Link: https://lkml.kernel.org/r/20240407081211.2292362-3-wangkefeng.wang@xxxxxxxxxx
Signed-off-by: Kefeng Wang <wangkefeng.wang@xxxxxxxxxx>
Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: Russell King <linux@xxxxxxxxxxxxxxx>
Cc: Will Deacon <will@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/arm/mm/fault.c | 28 +++++++++++++---------------
1 file changed, 13 insertions(+), 15 deletions(-)
--- a/arch/arm/mm/fault.c~arm-mm-drop-vm_fault_badmap-vm_fault_badaccess
+++ a/arch/arm/mm/fault.c
@@ -226,9 +226,6 @@ void do_bad_area(unsigned long addr, uns
}
#ifdef CONFIG_MMU
-#define VM_FAULT_BADMAP ((__force vm_fault_t)0x010000)
-#define VM_FAULT_BADACCESS ((__force vm_fault_t)0x020000)
-
static inline bool is_permission_fault(unsigned int fsr)
{
int fs = fsr_fs(fsr);
@@ -295,7 +292,8 @@ do_page_fault(unsigned long addr, unsign
if (!(vma->vm_flags & vm_flags)) {
vma_end_read(vma);
count_vm_vma_lock_event(VMA_LOCK_SUCCESS);
- fault = VM_FAULT_BADACCESS;
+ fault = 0;
+ code = SEGV_ACCERR;
goto bad_area;
}
fault = handle_mm_fault(vma, addr, flags | FAULT_FLAG_VMA_LOCK, regs);
@@ -321,7 +319,8 @@ lock_mmap:
retry:
vma = lock_mm_and_find_vma(mm, addr, regs);
if (unlikely(!vma)) {
- fault = VM_FAULT_BADMAP;
+ fault = 0;
+ code = SEGV_MAPERR;
goto bad_area;
}
@@ -329,10 +328,13 @@ retry:
* ok, we have a good vm_area for this memory access, check the
* permissions on the VMA allow for the fault which occurred.
*/
- if (!(vma->vm_flags & vm_flags))
- fault = VM_FAULT_BADACCESS;
- else
- fault = handle_mm_fault(vma, addr & PAGE_MASK, flags, regs);
+ if (!(vma->vm_flags & vm_flags)) {
+ fault = 0;
+ code = SEGV_ACCERR;
+ goto bad_area;
+ }
+
+ fault = handle_mm_fault(vma, addr & PAGE_MASK, flags, regs);
/* If we need to retry but a fatal signal is pending, handle the
* signal first. We do not need to release the mmap_lock because
@@ -358,10 +360,8 @@ retry:
mmap_read_unlock(mm);
done:
- /*
- * Handle the "normal" case first - VM_FAULT_MAJOR
- */
- if (likely(!(fault & (VM_FAULT_ERROR | VM_FAULT_BADMAP | VM_FAULT_BADACCESS))))
+ /* Handle the "normal" case first */
+ if (likely(!(fault & VM_FAULT_ERROR)))
return 0;
bad_area:
@@ -395,8 +395,6 @@ bad_area:
* isn't in our memory map..
*/
sig = SIGSEGV;
- code = fault == VM_FAULT_BADACCESS ?
- SEGV_ACCERR : SEGV_MAPERR;
}
__do_user_fault(addr, fsr, sig, code, regs);
_
Patches currently in -mm which might be from wangkefeng.wang@xxxxxxxxxx are
mm-backing-dev-use-group-allocation-free-of-per-cpu-counters-api.patch
mm-remove-__set_page_dirty_nobuffers.patch
arm64-mm-cleanup-__do_page_fault.patch
arm64-mm-accelerate-pagefault-when-vm_fault_badaccess.patch
arm-mm-accelerate-pagefault-when-vm_fault_badaccess.patch
powerpc-mm-accelerate-pagefault-when-badaccess.patch
riscv-mm-accelerate-pagefault-when-badaccess.patch
s390-mm-accelerate-pagefault-when-badaccess.patch
x86-mm-accelerate-pagefault-when-badaccess.patch
arm64-mm-drop-vm_fault_badmap-vm_fault_badaccess.patch
arm-mm-drop-vm_fault_badmap-vm_fault_badaccess.patch
