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Message-ID: <20230821123056.2109942-3-wangkefeng.wang@huawei.com>
Date: Mon, 21 Aug 2023 20:30:48 +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 02/10] arm64: mm: use try_vma_locked_page_fault()
Use new try_vma_locked_page_fault() helper to simplify code, also
pass struct vmf to __do_page_fault() directly instead of each
independent variable. No functional change intended.
Signed-off-by: Kefeng Wang <wangkefeng.wang@...wei.com>
---
arch/arm64/mm/fault.c | 60 ++++++++++++++++---------------------------
1 file changed, 22 insertions(+), 38 deletions(-)
diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c
index 2e5d1e238af9..2b7a1e610b3e 100644
--- a/arch/arm64/mm/fault.c
+++ b/arch/arm64/mm/fault.c
@@ -498,9 +498,8 @@ static void do_bad_area(unsigned long far, unsigned long esr,
#define VM_FAULT_BADACCESS ((__force vm_fault_t)0x020000)
static vm_fault_t __do_page_fault(struct mm_struct *mm,
- struct vm_area_struct *vma, unsigned long addr,
- unsigned int mm_flags, unsigned long vm_flags,
- struct pt_regs *regs)
+ struct vm_area_struct *vma,
+ struct vm_fault *vmf)
{
/*
* Ok, we have a good vm_area for this memory access, so we can handle
@@ -508,9 +507,9 @@ static vm_fault_t __do_page_fault(struct mm_struct *mm,
* Check that the permissions on the VMA allow for the fault which
* occurred.
*/
- if (!(vma->vm_flags & vm_flags))
+ if (!(vma->vm_flags & vmf->vm_flags))
return VM_FAULT_BADACCESS;
- return handle_mm_fault(vma, addr, mm_flags, regs);
+ return handle_mm_fault(vma, vmf->real_address, vmf->flags, vmf->regs);
}
static bool is_el0_instruction_abort(unsigned long esr)
@@ -533,10 +532,12 @@ static int __kprobes do_page_fault(unsigned long far, unsigned long esr,
const struct fault_info *inf;
struct mm_struct *mm = current->mm;
vm_fault_t fault;
- unsigned long vm_flags;
- unsigned int mm_flags = FAULT_FLAG_DEFAULT;
unsigned long addr = untagged_addr(far);
struct vm_area_struct *vma;
+ struct vm_fault vmf = {
+ .real_address = addr,
+ .flags = FAULT_FLAG_DEFAULT,
+ };
if (kprobe_page_fault(regs, esr))
return 0;
@@ -549,7 +550,7 @@ static int __kprobes do_page_fault(unsigned long far, unsigned long esr,
goto no_context;
if (user_mode(regs))
- mm_flags |= FAULT_FLAG_USER;
+ vmf.flags |= FAULT_FLAG_USER;
/*
* vm_flags tells us what bits we must have in vma->vm_flags
@@ -559,20 +560,20 @@ static int __kprobes do_page_fault(unsigned long far, unsigned long esr,
*/
if (is_el0_instruction_abort(esr)) {
/* It was exec fault */
- vm_flags = VM_EXEC;
- mm_flags |= FAULT_FLAG_INSTRUCTION;
+ vmf.vm_flags = VM_EXEC;
+ vmf.flags |= FAULT_FLAG_INSTRUCTION;
} else if (is_write_abort(esr)) {
/* It was write fault */
- vm_flags = VM_WRITE;
- mm_flags |= FAULT_FLAG_WRITE;
+ vmf.vm_flags = VM_WRITE;
+ vmf.flags |= FAULT_FLAG_WRITE;
} else {
/* It was read fault */
- vm_flags = VM_READ;
+ vmf.vm_flags = VM_READ;
/* Write implies read */
- vm_flags |= VM_WRITE;
+ vmf.vm_flags |= VM_WRITE;
/* If EPAN is absent then exec implies read */
if (!cpus_have_const_cap(ARM64_HAS_EPAN))
- vm_flags |= VM_EXEC;
+ vmf.vm_flags |= VM_EXEC;
}
if (is_ttbr0_addr(addr) && is_el1_permission_fault(addr, esr, regs)) {
@@ -587,26 +588,11 @@ static int __kprobes do_page_fault(unsigned long far, unsigned long esr,
perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, addr);
- if (!(mm_flags & FAULT_FLAG_USER))
- goto lock_mmap;
-
- vma = lock_vma_under_rcu(mm, addr);
- if (!vma)
- goto lock_mmap;
-
- if (!(vma->vm_flags & vm_flags)) {
- vma_end_read(vma);
- goto lock_mmap;
- }
- fault = handle_mm_fault(vma, addr, mm_flags | FAULT_FLAG_VMA_LOCK, regs);
- if (!(fault & (VM_FAULT_RETRY | VM_FAULT_COMPLETED)))
- vma_end_read(vma);
-
- if (!(fault & VM_FAULT_RETRY)) {
- count_vm_vma_lock_event(VMA_LOCK_SUCCESS);
+ fault = try_vma_locked_page_fault(&vmf);
+ if (fault == VM_FAULT_NONE)
+ goto retry;
+ if (!(fault & VM_FAULT_RETRY))
goto done;
- }
- count_vm_vma_lock_event(VMA_LOCK_RETRY);
/* Quick path to respond to signals */
if (fault_signal_pending(fault, regs)) {
@@ -614,8 +600,6 @@ static int __kprobes do_page_fault(unsigned long far, unsigned long esr,
goto no_context;
return 0;
}
-lock_mmap:
-
retry:
vma = lock_mm_and_find_vma(mm, addr, regs);
if (unlikely(!vma)) {
@@ -623,7 +607,7 @@ static int __kprobes do_page_fault(unsigned long far, unsigned long esr,
goto done;
}
- fault = __do_page_fault(mm, vma, addr, mm_flags, vm_flags, regs);
+ fault = __do_page_fault(mm, vma, &vmf);
/* Quick path to respond to signals */
if (fault_signal_pending(fault, regs)) {
@@ -637,7 +621,7 @@ static int __kprobes do_page_fault(unsigned long far, unsigned long esr,
return 0;
if (fault & VM_FAULT_RETRY) {
- mm_flags |= FAULT_FLAG_TRIED;
+ vmf.flags |= FAULT_FLAG_TRIED;
goto retry;
}
mmap_read_unlock(mm);
--
2.27.0
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