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Message-ID: <20230821123056.2109942-8-wangkefeng.wang@huawei.com>
Date: Mon, 21 Aug 2023 20:30:53 +0800
From: Kefeng Wang <wangkefeng.wang@...wei.com>
To: Andrew Morton <akpm@...ux-foundation.org>, <linux-mm@...ck.org>
CC: <surenb@...gle.com>, <willy@...radead.org>,
Russell King <linux@...linux.org.uk>,
Catalin Marinas <catalin.marinas@....com>,
Will Deacon <will@...nel.org>,
Huacai Chen <chenhuacai@...nel.org>,
WANG Xuerui <kernel@...0n.name>,
Michael Ellerman <mpe@...erman.id.au>,
Nicholas Piggin <npiggin@...il.com>,
Christophe Leroy <christophe.leroy@...roup.eu>,
Paul Walmsley <paul.walmsley@...ive.com>,
Palmer Dabbelt <palmer@...belt.com>,
Albert Ou <aou@...s.berkeley.edu>,
Alexander Gordeev <agordeev@...ux.ibm.com>,
Gerald Schaefer <gerald.schaefer@...ux.ibm.com>,
Heiko Carstens <hca@...ux.ibm.com>,
Vasily Gorbik <gor@...ux.ibm.com>,
Christian Borntraeger <borntraeger@...ux.ibm.com>,
Sven Schnelle <svens@...ux.ibm.com>,
Dave Hansen <dave.hansen@...ux.intel.com>,
Andy Lutomirski <luto@...nel.org>,
Peter Zijlstra <peterz@...radead.org>,
Thomas Gleixner <tglx@...utronix.de>,
Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
<x86@...nel.org>, "H . Peter Anvin" <hpa@...or.com>,
<linux-arm-kernel@...ts.infradead.org>,
<linux-kernel@...r.kernel.org>, <loongarch@...ts.linux.dev>,
<linuxppc-dev@...ts.ozlabs.org>, <linux-riscv@...ts.infradead.org>,
<linux-s390@...r.kernel.org>,
Kefeng Wang <wangkefeng.wang@...wei.com>
Subject: [PATCH rfc v2 07/10] ARM: mm: try VMA lock-based page fault handling first
Attempt VMA lock-based page fault handling first, and fall back
to the existing mmap_lock-based handling if that fails.
Signed-off-by: Kefeng Wang <wangkefeng.wang@...wei.com>
---
arch/arm/Kconfig | 1 +
arch/arm/mm/fault.c | 35 +++++++++++++++++++++++++----------
2 files changed, 26 insertions(+), 10 deletions(-)
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 1a6a6eb48a15..8b6d4507ccee 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -34,6 +34,7 @@ config ARM
select ARCH_OPTIONAL_KERNEL_RWX_DEFAULT if CPU_V7
select ARCH_SUPPORTS_ATOMIC_RMW
select ARCH_SUPPORTS_HUGETLBFS if ARM_LPAE
+ select ARCH_SUPPORTS_PER_VMA_LOCK
select ARCH_USE_BUILTIN_BSWAP
select ARCH_USE_CMPXCHG_LOCKREF
select ARCH_USE_MEMTEST
diff --git a/arch/arm/mm/fault.c b/arch/arm/mm/fault.c
index fef62e4a9edd..d53bb028899a 100644
--- a/arch/arm/mm/fault.c
+++ b/arch/arm/mm/fault.c
@@ -242,8 +242,11 @@ do_page_fault(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
struct vm_area_struct *vma;
int sig, code;
vm_fault_t fault;
- unsigned int flags = FAULT_FLAG_DEFAULT;
- unsigned long vm_flags = VM_ACCESS_FLAGS;
+ struct vm_fault vmf = {
+ .real_address = addr,
+ .flags = FAULT_FLAG_DEFAULT,
+ .vm_flags = VM_ACCESS_FLAGS,
+ };
if (kprobe_page_fault(regs, fsr))
return 0;
@@ -261,15 +264,15 @@ do_page_fault(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
goto no_context;
if (user_mode(regs))
- flags |= FAULT_FLAG_USER;
+ vmf.flags |= FAULT_FLAG_USER;
if (is_write_fault(fsr)) {
- flags |= FAULT_FLAG_WRITE;
- vm_flags = VM_WRITE;
+ vmf.flags |= FAULT_FLAG_WRITE;
+ vmf.vm_flags = VM_WRITE;
}
if (fsr & FSR_LNX_PF) {
- vm_flags = VM_EXEC;
+ vmf.vm_flags = VM_EXEC;
if (is_permission_fault(fsr) && !user_mode(regs))
die_kernel_fault("execution of memory",
@@ -278,6 +281,18 @@ do_page_fault(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, addr);
+ fault = try_vma_locked_page_fault(&vmf);
+ if (fault == VM_FAULT_NONE)
+ goto retry;
+ if (!(fault & VM_FAULT_RETRY))
+ goto done;
+
+ if (fault_signal_pending(fault, regs)) {
+ if (!user_mode(regs))
+ goto no_context;
+ return 0;
+ }
+
retry:
vma = lock_mm_and_find_vma(mm, addr, regs);
if (unlikely(!vma)) {
@@ -289,10 +304,10 @@ do_page_fault(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
* 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))
+ if (!(vma->vm_flags & vmf.vm_flags))
fault = VM_FAULT_BADACCESS;
else
- fault = handle_mm_fault(vma, addr & PAGE_MASK, flags, regs);
+ fault = handle_mm_fault(vma, addr & PAGE_MASK, vmf.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
@@ -310,13 +325,13 @@ do_page_fault(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
if (!(fault & VM_FAULT_ERROR)) {
if (fault & VM_FAULT_RETRY) {
- flags |= FAULT_FLAG_TRIED;
+ vmf.flags |= FAULT_FLAG_TRIED;
goto retry;
}
}
mmap_read_unlock(mm);
-
+done:
/*
* Handle the "normal" case first - VM_FAULT_MAJOR
*/
--
2.27.0
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