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Peter Anvin" , , , , , , , Kefeng Wang Subject: [PATCH rfc v2 02/10] arm64: mm: use try_vma_locked_page_fault() Date: Mon, 21 Aug 2023 20:30:48 +0800 Message-ID: <20230821123056.2109942-3-wangkefeng.wang@huawei.com> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20230821123056.2109942-1-wangkefeng.wang@huawei.com> References: <20230821123056.2109942-1-wangkefeng.wang@huawei.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Originating-IP: [10.175.112.125] X-ClientProxiedBy: dggems705-chm.china.huawei.com (10.3.19.182) To dggpemm100001.china.huawei.com (7.185.36.93) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" 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 --- 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 lon= g esr, #define VM_FAULT_BADACCESS ((__force vm_fault_t)0x020000) =20 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); } =20 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 =3D current->mm; vm_fault_t fault; - unsigned long vm_flags; - unsigned int mm_flags =3D FAULT_FLAG_DEFAULT; unsigned long addr =3D untagged_addr(far); struct vm_area_struct *vma; + struct vm_fault vmf =3D { + .real_address =3D addr, + .flags =3D FAULT_FLAG_DEFAULT, + }; =20 if (kprobe_page_fault(regs, esr)) return 0; @@ -549,7 +550,7 @@ static int __kprobes do_page_fault(unsigned long far, u= nsigned long esr, goto no_context; =20 if (user_mode(regs)) - mm_flags |=3D FAULT_FLAG_USER; + vmf.flags |=3D FAULT_FLAG_USER; =20 /* * 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 =3D VM_EXEC; - mm_flags |=3D FAULT_FLAG_INSTRUCTION; + vmf.vm_flags =3D VM_EXEC; + vmf.flags |=3D FAULT_FLAG_INSTRUCTION; } else if (is_write_abort(esr)) { /* It was write fault */ - vm_flags =3D VM_WRITE; - mm_flags |=3D FAULT_FLAG_WRITE; + vmf.vm_flags =3D VM_WRITE; + vmf.flags |=3D FAULT_FLAG_WRITE; } else { /* It was read fault */ - vm_flags =3D VM_READ; + vmf.vm_flags =3D VM_READ; /* Write implies read */ - vm_flags |=3D VM_WRITE; + vmf.vm_flags |=3D VM_WRITE; /* If EPAN is absent then exec implies read */ if (!cpus_have_const_cap(ARM64_HAS_EPAN)) - vm_flags |=3D VM_EXEC; + vmf.vm_flags |=3D VM_EXEC; } =20 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, =20 perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, addr); =20 - if (!(mm_flags & FAULT_FLAG_USER)) - goto lock_mmap; - - vma =3D 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 =3D 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 =3D try_vma_locked_page_fault(&vmf); + if (fault =3D=3D VM_FAULT_NONE) + goto retry; + if (!(fault & VM_FAULT_RETRY)) goto done; - } - count_vm_vma_lock_event(VMA_LOCK_RETRY); =20 /* 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, u= nsigned long esr, goto no_context; return 0; } -lock_mmap: - retry: vma =3D lock_mm_and_find_vma(mm, addr, regs); if (unlikely(!vma)) { @@ -623,7 +607,7 @@ static int __kprobes do_page_fault(unsigned long far, u= nsigned long esr, goto done; } =20 - fault =3D __do_page_fault(mm, vma, addr, mm_flags, vm_flags, regs); + fault =3D __do_page_fault(mm, vma, &vmf); =20 /* 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, u= nsigned long esr, return 0; =20 if (fault & VM_FAULT_RETRY) { - mm_flags |=3D FAULT_FLAG_TRIED; + vmf.flags |=3D FAULT_FLAG_TRIED; goto retry; } mmap_read_unlock(mm); --=20 2.27.0