From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2C6E8C6FD1D for ; Wed, 15 Mar 2023 03:05:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229487AbjCODF3 (ORCPT ); Tue, 14 Mar 2023 23:05:29 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44494 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229648AbjCODF2 (ORCPT ); Tue, 14 Mar 2023 23:05:28 -0400 Received: from mail-pl1-x62f.google.com (mail-pl1-x62f.google.com [IPv6:2607:f8b0:4864:20::62f]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 09D3E574F7 for ; Tue, 14 Mar 2023 20:05:27 -0700 (PDT) Received: by mail-pl1-x62f.google.com with SMTP id ja10so8976052plb.5 for ; Tue, 14 Mar 2023 20:05:27 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=rivosinc-com.20210112.gappssmtp.com; s=20210112; t=1678849526; h=to:from:cc:content-transfer-encoding:mime-version:references :in-reply-to:message-id:date:subject:from:to:cc:subject:date :message-id:reply-to; bh=hPLiCKdxpc2r5PKNkHmqRCNmdb24wQijBhgYpLkC43U=; b=hZOWobSL1PKWIUT7UWS9tniLiB9mdfLQVx/Z/9zPgZaqvjnOteqzCtEB9HjY6uDm5Z iih9EdmkZVUeQo0xOfl1VcnfVacdcLCd8AJJAPxhyA2sm6Xke46e1e2rJ7Rh0BSVXkF8 LPvQJyzonpQFWDXt2SUjjq9ID4+tvuPP8BALY8prYRlpppPYUlsITVn79fdnaiUXQEF1 deb+t9btxFOPW+9acEXIhNbZp2doaKT5YgC3FtBNm79vfC3LW+6mWJ6+9PBqPIyH0Kic Coc17KHtjWazt5MqaHhgFOTwgQhPQ0N0ANZIoSAUsfoul0ONsbg8PSj+Y8JcyFTwqcEL HRCg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; t=1678849526; h=to:from:cc:content-transfer-encoding:mime-version:references :in-reply-to:message-id:date:subject:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=hPLiCKdxpc2r5PKNkHmqRCNmdb24wQijBhgYpLkC43U=; b=woUlbd6RSbQcw5BMOzGHU6DiGuAKysiNe2yvfw0ziE/zwxAmcrS95Z3NmcsZEsohZ0 fvfFpLAX+Q1o6TOujs+GesCJT0JAqrt9KgbzLtOpVcsRe4wp7thHswhsQc1e1EY1gwE9 VHe37csQA3wAmiKx4zW1mtpq2o6i4W6WdBqkRJS9XWjMCTtXRNUKYxi2+32yiCYHCqx8 LpN/VypFMibGOeomsLMNvzTMU/IySenVVter3cikSQjTxjo3VgDgGq6MMMWP/96dymPQ LZ0nQAuXu/FTtAhjbgVJUS+0fo82Wnhp93hipJb9M1o0ylCpLx5bqTKEf9L1mD27Y29k SSNQ== X-Gm-Message-State: AO0yUKU8fEZOg0VZU7/UAOJ+qx1A5pai1c+79pejBC/Sj6pVxscI5kn/ 4teI/rOd6fjRyKVf5Fsm5w5xFQ== X-Google-Smtp-Source: AK7set9vypcudDyWo/h8khv9E95mQjVI9aZbPGtfY3t0wFWv20PLrTeh2GiFiqI+9gk8Y0mpUagQ+Q== X-Received: by 2002:a17:902:ec8a:b0:19e:416e:abf5 with SMTP id x10-20020a170902ec8a00b0019e416eabf5mr1078987plg.34.1678849526457; Tue, 14 Mar 2023 20:05:26 -0700 (PDT) Received: from localhost ([50.221.140.188]) by smtp.gmail.com with ESMTPSA id s30-20020a63451e000000b0050300a7c8c2sm2194674pga.89.2023.03.14.20.05.25 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 14 Mar 2023 20:05:26 -0700 (PDT) Subject: [PATCH v2 1/6] riscv/mm/fault: simplify code for do_page_fault() Date: Tue, 14 Mar 2023 20:03:54 -0700 Message-Id: <20230315030359.14162-2-palmer@rivosinc.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230315030359.14162-1-palmer@rivosinc.com> References: <20230315030359.14162-1-palmer@rivosinc.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Cc: linux-mm@kvack.org, linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Tong Tiangen , Palmer Dabbelt From: Palmer Dabbelt To: akpm@linux-foundation.org Precedence: bulk List-ID: X-Mailing-List: linux-s390@vger.kernel.org From: Tong Tiangen To make the code more hierarchical and readable, we fold vma related judgments into __do_page_fault(). And to simplify the code, move the tsk->thread.bad_cause's setting into bad_area(). No functional change intended. Signed-off-by: Tong Tiangen Signed-off-by: Palmer Dabbelt --- arch/riscv/mm/fault.c | 77 +++++++++++++++++++++++-------------------- 1 file changed, 41 insertions(+), 36 deletions(-) diff --git a/arch/riscv/mm/fault.c b/arch/riscv/mm/fault.c index 460f785f6e09..0a8c9afeee22 100644 --- a/arch/riscv/mm/fault.c +++ b/arch/riscv/mm/fault.c @@ -85,6 +85,8 @@ static inline void mm_fault_error(struct pt_regs *regs, unsigned long addr, vm_f static inline void bad_area(struct pt_regs *regs, struct mm_struct *mm, int code, unsigned long addr) { + current->thread.bad_cause = regs->cause; + /* * Something tried to access memory that isn't in our memory map. * Fix it, but check if it's kernel or user first. @@ -200,6 +202,38 @@ static inline bool access_error(unsigned long cause, struct vm_area_struct *vma) return false; } +#define VM_FAULT_BADMAP ((__force vm_fault_t)0x010000) +#define VM_FAULT_BADACCESS ((__force vm_fault_t)0x020000) + +static vm_fault_t __do_page_fault(struct mm_struct *mm, unsigned long addr, + unsigned int mm_flags, struct pt_regs *regs) +{ + struct vm_area_struct *vma = find_vma(mm, addr); + + if (unlikely(!vma)) + return VM_FAULT_BADMAP; + + if (unlikely(vma->vm_start > addr)) { + if (unlikely(!(vma->vm_flags & VM_GROWSDOWN) || + expand_stack(vma, addr))) + return VM_FAULT_BADMAP; + } + + /* + * Ok, we have a good vm_area for this memory access, so + * we can handle it. + */ + if (unlikely(access_error(regs->cause, vma))) + return VM_FAULT_BADACCESS; + + /* + * If for any reason at all we could not handle the fault, + * make sure we exit gracefully rather than endlessly redo + * the fault. + */ + return handle_mm_fault(vma, addr, mm_flags, regs); +} + /* * This routine handles page faults. It determines the address and the * problem, and then passes it off to one of the appropriate routines. @@ -207,7 +241,6 @@ static inline bool access_error(unsigned long cause, struct vm_area_struct *vma) asmlinkage void do_page_fault(struct pt_regs *regs) { struct task_struct *tsk; - struct vm_area_struct *vma; struct mm_struct *mm; unsigned long addr, cause; unsigned int flags = FAULT_FLAG_DEFAULT; @@ -282,44 +315,16 @@ asmlinkage void do_page_fault(struct pt_regs *regs) flags |= FAULT_FLAG_INSTRUCTION; retry: mmap_read_lock(mm); - vma = find_vma(mm, addr); - if (unlikely(!vma)) { - tsk->thread.bad_cause = cause; - bad_area(regs, mm, code, addr); - return; - } - if (likely(vma->vm_start <= addr)) - goto good_area; - if (unlikely(!(vma->vm_flags & VM_GROWSDOWN))) { - tsk->thread.bad_cause = cause; - bad_area(regs, mm, code, addr); - return; - } - if (unlikely(expand_stack(vma, addr))) { - tsk->thread.bad_cause = cause; - bad_area(regs, mm, code, addr); - return; - } - /* - * Ok, we have a good vm_area for this memory access, so - * we can handle it. - */ -good_area: - code = SEGV_ACCERR; + fault = __do_page_fault(mm, addr, flags, regs); - if (unlikely(access_error(cause, vma))) { - tsk->thread.bad_cause = cause; - bad_area(regs, mm, code, addr); - return; - } + if (unlikely(fault & VM_FAULT_BADMAP)) + return bad_area(regs, mm, code, addr); - /* - * If for any reason at all we could not handle the fault, - * make sure we exit gracefully rather than endlessly redo - * the fault. - */ - fault = handle_mm_fault(vma, addr, flags, regs); + if (unlikely(fault & VM_FAULT_BADACCESS)) { + code = SEGV_ACCERR; + return bad_area(regs, mm, code, addr); + } /* * If we need to retry but a fatal signal is pending, handle the -- 2.39.2