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Peter Anvin" , , , , , , , Kefeng Wang Subject: [PATCH rfc v2 03/10] x86: mm: use try_vma_locked_page_fault() Date: Mon, 21 Aug 2023 20:30:49 +0800 Message-ID: <20230821123056.2109942-4-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 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 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230821_053120_806331_ECD8FBEF X-CRM114-Status: GOOD ( 16.00 ) X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org Use new try_vma_locked_page_fault() helper to simplify code. No functional change intended. Signed-off-by: Kefeng Wang --- arch/x86/mm/fault.c | 55 +++++++++++++++++++-------------------------- 1 file changed, 23 insertions(+), 32 deletions(-) diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c index ab778eac1952..3edc9edc0b28 100644 --- a/arch/x86/mm/fault.c +++ b/arch/x86/mm/fault.c @@ -1227,6 +1227,13 @@ do_kern_addr_fault(struct pt_regs *regs, unsigned long hw_error_code, } NOKPROBE_SYMBOL(do_kern_addr_fault); +#ifdef CONFIG_PER_VMA_LOCK +bool arch_vma_access_error(struct vm_area_struct *vma, struct vm_fault *vmf) +{ + return access_error(vmf->fault_code, vma); +} +#endif + /* * Handle faults in the user portion of the address space. Nothing in here * should check X86_PF_USER without a specific justification: for almost @@ -1241,13 +1248,13 @@ void do_user_addr_fault(struct pt_regs *regs, unsigned long address) { struct vm_area_struct *vma; - struct task_struct *tsk; - struct mm_struct *mm; + struct mm_struct *mm = current->mm; vm_fault_t fault; - unsigned int flags = FAULT_FLAG_DEFAULT; - - tsk = current; - mm = tsk->mm; + struct vm_fault vmf = { + .real_address = address, + .fault_code = error_code, + .flags = FAULT_FLAG_DEFAULT + }; if (unlikely((error_code & (X86_PF_USER | X86_PF_INSTR)) == X86_PF_INSTR)) { /* @@ -1311,7 +1318,7 @@ void do_user_addr_fault(struct pt_regs *regs, */ if (user_mode(regs)) { local_irq_enable(); - flags |= FAULT_FLAG_USER; + vmf.flags |= FAULT_FLAG_USER; } else { if (regs->flags & X86_EFLAGS_IF) local_irq_enable(); @@ -1326,11 +1333,11 @@ void do_user_addr_fault(struct pt_regs *regs, * maybe_mkwrite() can create a proper shadow stack PTE. */ if (error_code & X86_PF_SHSTK) - flags |= FAULT_FLAG_WRITE; + vmf.flags |= FAULT_FLAG_WRITE; if (error_code & X86_PF_WRITE) - flags |= FAULT_FLAG_WRITE; + vmf.flags |= FAULT_FLAG_WRITE; if (error_code & X86_PF_INSTR) - flags |= FAULT_FLAG_INSTRUCTION; + vmf.flags |= FAULT_FLAG_INSTRUCTION; #ifdef CONFIG_X86_64 /* @@ -1350,26 +1357,11 @@ void do_user_addr_fault(struct pt_regs *regs, } #endif - if (!(flags & FAULT_FLAG_USER)) - goto lock_mmap; - - vma = lock_vma_under_rcu(mm, address); - if (!vma) - goto lock_mmap; - - if (unlikely(access_error(error_code, vma))) { - vma_end_read(vma); - goto lock_mmap; - } - fault = handle_mm_fault(vma, address, 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)) { @@ -1379,7 +1371,6 @@ void do_user_addr_fault(struct pt_regs *regs, ARCH_DEFAULT_PKEY); return; } -lock_mmap: retry: vma = lock_mm_and_find_vma(mm, address, regs); @@ -1410,7 +1401,7 @@ void do_user_addr_fault(struct pt_regs *regs, * userland). The return to userland is identified whenever * FAULT_FLAG_USER|FAULT_FLAG_KILLABLE are both set in flags. */ - fault = handle_mm_fault(vma, address, flags, regs); + fault = handle_mm_fault(vma, address, vmf.flags, regs); if (fault_signal_pending(fault, regs)) { /* @@ -1434,7 +1425,7 @@ void do_user_addr_fault(struct pt_regs *regs, * that we made any progress. Handle this case first. */ if (unlikely(fault & VM_FAULT_RETRY)) { - flags |= FAULT_FLAG_TRIED; + vmf.flags |= FAULT_FLAG_TRIED; goto retry; }