The patch titled
Subject: arm64: mm: drop VM_FAULT_BADMAP/VM_FAULT_BADACCESS
has been added to the -mm mm-unstable branch. Its filename is
arm64-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/arm64-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: arm64: mm: drop VM_FAULT_BADMAP/VM_FAULT_BADACCESS
Date: Thu, 11 Apr 2024 21:09:24 +0800
Patch series "mm: remove arch's private VM_FAULT_BADMAP/BADACCESS", v2.
Directly set SEGV_MAPRR or SEGV_ACCERR for arm/arm64 to remove the last
two arch's private vm_fault reasons.
This patch (of 2):
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/20240411130925.73281-1-wangkefeng.wang@xxxxxxxxxx
Link: https://lkml.kernel.org/r/20240411130925.73281-2-wangkefeng.wang@xxxxxxxxxx
Signed-off-by: Kefeng Wang <wangkefeng.wang@xxxxxxxxxx>
Cc: Aishwarya TCV <aishwarya.tcv@xxxxxxx>
Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: Cristian Marussi <cristian.marussi@xxxxxxx>
Cc: Mark Brown <broonie@xxxxxxxxxx>
Cc: Russell King <linux@xxxxxxxxxxxxxxx>
Cc: Will Deacon <will@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/arm64/mm/fault.c | 43 ++++++++++++++++++----------------------
1 file changed, 20 insertions(+), 23 deletions(-)
--- a/arch/arm64/mm/fault.c~arm64-mm-drop-vm_fault_badmap-vm_fault_badaccess
+++ a/arch/arm64/mm/fault.c
@@ -500,9 +500,6 @@ static bool is_write_abort(unsigned long
return (esr & ESR_ELx_WNR) && !(esr & ESR_ELx_CM);
}
-#define VM_FAULT_BADMAP ((__force vm_fault_t)0x010000)
-#define VM_FAULT_BADACCESS ((__force vm_fault_t)0x020000)
-
static int __kprobes do_page_fault(unsigned long far, unsigned long esr,
struct pt_regs *regs)
{
@@ -513,6 +510,7 @@ static int __kprobes do_page_fault(unsig
unsigned int mm_flags = FAULT_FLAG_DEFAULT;
unsigned long addr = untagged_addr(far);
struct vm_area_struct *vma;
+ int si_code;
if (kprobe_page_fault(regs, esr))
return 0;
@@ -572,9 +570,10 @@ static int __kprobes do_page_fault(unsig
if (!(vma->vm_flags & vm_flags)) {
vma_end_read(vma);
- fault = VM_FAULT_BADACCESS;
+ fault = 0;
+ si_code = SEGV_ACCERR;
count_vm_vma_lock_event(VMA_LOCK_SUCCESS);
- goto done;
+ goto bad_area;
}
fault = handle_mm_fault(vma, addr, mm_flags | FAULT_FLAG_VMA_LOCK, regs);
if (!(fault & (VM_FAULT_RETRY | VM_FAULT_COMPLETED)))
@@ -599,15 +598,19 @@ lock_mmap:
retry:
vma = lock_mm_and_find_vma(mm, addr, regs);
if (unlikely(!vma)) {
- fault = VM_FAULT_BADMAP;
- goto done;
+ fault = 0;
+ si_code = SEGV_MAPERR;
+ goto bad_area;
}
- if (!(vma->vm_flags & vm_flags))
- fault = VM_FAULT_BADACCESS;
- else
- fault = handle_mm_fault(vma, addr, mm_flags, regs);
+ if (!(vma->vm_flags & vm_flags)) {
+ mmap_read_unlock(mm);
+ fault = 0;
+ si_code = SEGV_ACCERR;
+ goto bad_area;
+ }
+ fault = handle_mm_fault(vma, addr, mm_flags, regs);
/* Quick path to respond to signals */
if (fault_signal_pending(fault, regs)) {
if (!user_mode(regs))
@@ -626,13 +629,12 @@ retry:
mmap_read_unlock(mm);
done:
- /*
- * Handle the "normal" (no error) case first.
- */
- if (likely(!(fault & (VM_FAULT_ERROR | VM_FAULT_BADMAP |
- VM_FAULT_BADACCESS))))
+ /* Handle the "normal" (no error) case first. */
+ if (likely(!(fault & VM_FAULT_ERROR)))
return 0;
+ si_code = SEGV_MAPERR;
+bad_area:
/*
* If we are in kernel mode at this point, we have no context to
* handle this fault with.
@@ -667,13 +669,8 @@ done:
arm64_force_sig_mceerr(BUS_MCEERR_AR, far, lsb, inf->name);
} else {
- /*
- * Something tried to access memory that isn't in our memory
- * map.
- */
- arm64_force_sig_fault(SIGSEGV,
- fault == VM_FAULT_BADACCESS ? SEGV_ACCERR : SEGV_MAPERR,
- far, inf->name);
+ /* Something tried to access memory that out of memory map */
+ arm64_force_sig_fault(SIGSEGV, si_code, far, inf->name);
}
return 0;
_
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
riscv-mm-accelerate-pagefault-when-badaccess-fix.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
