Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751748AbaDRMxu (ORCPT ); Fri, 18 Apr 2014 08:53:50 -0400 Received: from mail-bn1bn0104.outbound.protection.outlook.com ([157.56.110.104]:16469 "EHLO na01-bn1-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752222AbaDRMmM (ORCPT ); Fri, 18 Apr 2014 08:42:12 -0400 From: Ley Foon Tan To: , , CC: Ley Foon Tan , , Subject: [PATCH 08/28] nios2: MMU Fault handling Date: Fri, 18 Apr 2014 20:26:52 +0800 Message-ID: <1397824031-4892-6-git-send-email-lftan@altera.com> X-Mailer: git-send-email 1.8.3.2 In-Reply-To: <1397824031-4892-1-git-send-email-lftan@altera.com> References: <1397824031-4892-1-git-send-email-lftan@altera.com> MIME-Version: 1.0 Content-Type: text/plain X-EOPAttributedMessage: 0 X-Forefront-Antispam-Report: CIP:66.35.236.232;CTRY:US;IPV:NLI;EFV:NLI;SFV:NSPM;SFS:(10019001)(6009001)(458001)(189002)(199002)(22564002)(42186004)(46102001)(76482001)(48376002)(16796002)(74662001)(31966008)(74502001)(80022001)(47776003)(4396001)(50226001)(77982001)(87286001)(87936001)(44976005)(83322001)(19580395003)(19580405001)(6806004)(81342001)(20776003)(81542001)(62966002)(92726001)(99396002)(2201001)(97736001)(84676001)(83072002)(85852003)(2009001)(50986999)(76176999)(36756003)(80976001)(88136002)(89996001)(77156001)(50466002)(92566001)(93916002)(86362001);DIR:OUT;SFP:1102;SCL:1;SRVR:BL2FFO11HUB008;H:SJ-ITEXEDGE02.altera.priv.altera.com;FPR:8829D0D6.A6FE9FEC.70F2AB63.2F4E772.20655;MLV:sfv;PTR:InfoDomainNonexistent;MX:1;A:1;LANG:en; X-OriginatorOrg: altera.onmicrosoft.com X-Forefront-PRVS: 018577E36E Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This patch adds support for the handling of the MMU faults (exception entry code introduced by a previous patch, kernel/entry.S). Signed-off-by: Ley Foon Tan --- arch/nios2/mm/extable.c | 25 +++++ arch/nios2/mm/fault.c | 242 ++++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 267 insertions(+) create mode 100644 arch/nios2/mm/extable.c create mode 100644 arch/nios2/mm/fault.c diff --git a/arch/nios2/mm/extable.c b/arch/nios2/mm/extable.c new file mode 100644 index 0000000..4d2fc5a589d09492630ddff2a52a7a6a96ab6486 --- /dev/null +++ b/arch/nios2/mm/extable.c @@ -0,0 +1,25 @@ +/* + * Copyright (C) 2010, Tobias Klauser + * Copyright (C) 2009, Wind River Systems Inc + * Implemented by fredrik.markstrom@gmail.com and ivarholmqvist@gmail.com + * + * This file is subject to the terms and conditions of the GNU General Public + * License. See the file "COPYING" in the main directory of this archive + * for more details. + */ + +#include +#include + +int fixup_exception(struct pt_regs *regs) +{ + const struct exception_table_entry *fixup; + + fixup = search_exception_tables(regs->ea); + if (fixup) { + regs->ea = fixup->fixup; + return 1; + } + + return 0; +} diff --git a/arch/nios2/mm/fault.c b/arch/nios2/mm/fault.c new file mode 100644 index 0000000..96258b18fc32204b98a70b2dcadc3cb8661539bc --- /dev/null +++ b/arch/nios2/mm/fault.c @@ -0,0 +1,242 @@ +/* + * Copyright (C) 2009 Wind River Systems Inc + * Implemented by fredrik.markstrom@gmail.com and ivarholmqvist@gmail.com + * + * based on arch/mips/mm/fault.c which is: + * + * Copyright (C) 1995-2000 Ralf Baechle + * + * This file is subject to the terms and conditions of the GNU General Public + * License. See the file "COPYING" in the main directory of this archive + * for more details. + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include +#include + +#define EXC_SUPERV_INSN_ACCESS 9 /* Supervisor only instruction address */ +#define EXC_SUPERV_DATA_ACCESS 11 /* Supervisor only data address */ +#define EXC_X_PROTECTION_FAULT 13 /* TLB permission violation (x) */ +#define EXC_R_PROTECTION_FAULT 14 /* TLB permission violation (r) */ +#define EXC_W_PROTECTION_FAULT 15 /* TLB permission violation (w) */ + +/* + * This routine handles page faults. It determines the address, + * and the problem, and then passes it off to one of the appropriate + * routines. + */ +asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long cause, + unsigned long address) +{ + struct vm_area_struct *vma = NULL; + struct task_struct *tsk = current; + struct mm_struct *mm = tsk->mm; + int code = SEGV_MAPERR; + int fault; + unsigned int flags = 0; + + cause >>= 2; + + /* Restart the instruction */ + regs->ea -= 4; + + /* + * We fault-in kernel-space virtual memory on-demand. The + * 'reference' page table is init_mm.pgd. + * + * NOTE! We MUST NOT take any locks for this case. We may + * be in an interrupt or a critical region, and should + * only copy the information from the master page table, + * nothing more. + */ + if (unlikely(address >= VMALLOC_START && address <= VMALLOC_END)) { + if (user_mode(regs)) + goto bad_area_nosemaphore; + else + goto vmalloc_fault; + } + + if (unlikely(address >= TASK_SIZE)) + goto bad_area_nosemaphore; + + /* + * If we're in an interrupt or have no user + * context, we must not take the fault.. + */ + if (in_atomic() || !mm) + goto bad_area_nosemaphore; + + if (user_mode(regs)) + flags |= FAULT_FLAG_USER; + + down_read(&mm->mmap_sem); + vma = find_vma(mm, address); + if (!vma) + goto bad_area; + if (vma->vm_start <= address) + goto good_area; + if (!(vma->vm_flags & VM_GROWSDOWN)) + goto bad_area; + if (expand_stack(vma, address)) + goto bad_area; +/* + * Ok, we have a good vm_area for this memory access, so + * we can handle it.. + */ +good_area: + code = SEGV_ACCERR; + + switch (cause) { + case EXC_SUPERV_INSN_ACCESS: + goto bad_area; + case EXC_SUPERV_DATA_ACCESS: + goto bad_area; + case EXC_X_PROTECTION_FAULT: + if (!(vma->vm_flags & VM_EXEC)) + goto bad_area; + break; + case EXC_R_PROTECTION_FAULT: + if (!(vma->vm_flags & VM_READ)) + goto bad_area; + break; + case EXC_W_PROTECTION_FAULT: + if (!(vma->vm_flags & VM_WRITE)) + goto bad_area; + flags = FAULT_FLAG_WRITE; + break; + } + +survive: + /* + * If for any reason at all we couldn't handle the fault, + * make sure we exit gracefully rather than endlessly redo + * the fault. + */ + fault = handle_mm_fault(mm, vma, address, flags); + if (unlikely(fault & VM_FAULT_ERROR)) { + if (fault & VM_FAULT_OOM) + goto out_of_memory; + else if (fault & VM_FAULT_SIGBUS) + goto do_sigbus; + BUG(); + } + if (fault & VM_FAULT_MAJOR) + tsk->maj_flt++; + else + tsk->min_flt++; + + up_read(&mm->mmap_sem); + return; + +/* + * Something tried to access memory that isn't in our memory map.. + * Fix it, but check if it's kernel or user first.. + */ +bad_area: + up_read(&mm->mmap_sem); + +bad_area_nosemaphore: + /* User mode accesses just cause a SIGSEGV */ + if (user_mode(regs)) { + _exception(SIGSEGV, regs, code, address); + return; + } + +no_context: + /* Are we prepared to handle this kernel fault? */ + if (fixup_exception(regs)) + return; + + /* + * Oops. The kernel tried to access some bad page. We'll have to + * terminate things with extreme prejudice. + */ + bust_spinlocks(1); + + pr_alert("Unable to handle kernel %s at virtual address %08lx", + address < PAGE_SIZE ? "NULL pointer dereference" : + "paging request", address); + pr_alert("ea = %08lx, ra = %08lx, cause = %ld\n", regs->ea, regs->ra, + cause); + panic("Oops"); + return; + +/* + * We ran out of memory, or some other thing happened to us that made + * us unable to handle the page fault gracefully. + */ +out_of_memory: + up_read(&mm->mmap_sem); + if (is_global_init(tsk)) { + yield(); + down_read(&mm->mmap_sem); + goto survive; + } + if (!user_mode(regs)) + goto no_context; + pagefault_out_of_memory(); + return; + +do_sigbus: + up_read(&mm->mmap_sem); + + /* Kernel mode? Handle exceptions or die */ + if (!user_mode(regs)) + goto no_context; + + _exception(SIGBUS, regs, BUS_ADRERR, address); + return; + +vmalloc_fault: + { + /* + * Synchronize this task's top level page-table + * with the 'reference' page table. + * + * Do _not_ use "tsk" here. We might be inside + * an interrupt in the middle of a task switch.. + */ + int offset = pgd_index(address); + pgd_t *pgd, *pgd_k; + pud_t *pud, *pud_k; + pmd_t *pmd, *pmd_k; + pte_t *pte_k; + + pgd = pgd_current + offset; + pgd_k = init_mm.pgd + offset; + + if (!pgd_present(*pgd_k)) + goto no_context; + set_pgd(pgd, *pgd_k); + + pud = pud_offset(pgd, address); + pud_k = pud_offset(pgd_k, address); + if (!pud_present(*pud_k)) + goto no_context; + pmd = pmd_offset(pud, address); + pmd_k = pmd_offset(pud_k, address); + if (!pmd_present(*pmd_k)) + goto no_context; + set_pmd(pmd, *pmd_k); + + pte_k = pte_offset_kernel(pmd_k, address); + if (!pte_present(*pte_k)) + goto no_context; + + flush_tlb_one(address); + return; + } +} -- 1.8.3.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/