From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752231Ab1GUJTH (ORCPT ); Thu, 21 Jul 2011 05:19:07 -0400 Received: from a.ns.miles-group.at ([95.130.255.143]:57239 "EHLO radon.swed.at" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751934Ab1GUJSq (ORCPT ); Thu, 21 Jul 2011 05:18:46 -0400 From: Richard Weinberger To: akpm@linux-foundation.org Cc: linux-kernel@vger.kernel.org, user-mode-linux-devel@lists.sourceforge.net, Richard Weinberger Subject: [PATCH 06/10] um: Set __HAVE_ARCH_GATE_AREA for i386 Date: Thu, 21 Jul 2011 11:18:30 +0200 Message-Id: <1311239914-8301-6-git-send-email-richard@nod.at> X-Mailer: git-send-email 1.7.6 In-Reply-To: <1311239914-8301-1-git-send-email-richard@nod.at> References: <1311239914-8301-1-git-send-email-richard@nod.at> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When UML is unable to reuse the host's vDSO FIXADDR_USER_START is zero. To handle this special case correclty we have to implement custom gate area helper methods. Signed-off-by: Richard Weinberger --- arch/um/sys-i386/Makefile | 2 +- arch/um/sys-i386/asm/elf.h | 2 + arch/um/sys-i386/mem.c | 62 ++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 65 insertions(+), 1 deletions(-) create mode 100644 arch/um/sys-i386/mem.c diff --git a/arch/um/sys-i386/Makefile b/arch/um/sys-i386/Makefile index b1da91c..daaea15 100644 --- a/arch/um/sys-i386/Makefile +++ b/arch/um/sys-i386/Makefile @@ -4,7 +4,7 @@ obj-y = bug.o bugs.o checksum.o delay.o fault.o ksyms.o ldt.o ptrace.o \ ptrace_user.o setjmp.o signal.o stub.o stub_segv.o syscalls.o sysrq.o \ - sys_call_table.o tls.o atomic64_cx8_32.o + sys_call_table.o tls.o atomic64_cx8_32.o mem.o obj-$(CONFIG_BINFMT_ELF) += elfcore.o diff --git a/arch/um/sys-i386/asm/elf.h b/arch/um/sys-i386/asm/elf.h index d964a41..4230555 100644 --- a/arch/um/sys-i386/asm/elf.h +++ b/arch/um/sys-i386/asm/elf.h @@ -105,6 +105,8 @@ extern unsigned long __kernel_vsyscall; #define FIXADDR_USER_START VSYSCALL_BASE #define FIXADDR_USER_END VSYSCALL_END +#define __HAVE_ARCH_GATE_AREA 1 + /* * Architecture-neutral AT_ values in 0-17, leave some room * for more of them, start the x86-specific ones at 32. diff --git a/arch/um/sys-i386/mem.c b/arch/um/sys-i386/mem.c new file mode 100644 index 0000000..639900a --- /dev/null +++ b/arch/um/sys-i386/mem.c @@ -0,0 +1,62 @@ +/* + * Copyright (C) 2011 Richard Weinberger + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include +#include +#include + +static struct vm_area_struct gate_vma; + +static int __init gate_vma_init(void) +{ + if (!FIXADDR_USER_START) + return 0; + + gate_vma.vm_mm = NULL; + gate_vma.vm_start = FIXADDR_USER_START; + gate_vma.vm_end = FIXADDR_USER_END; + gate_vma.vm_flags = VM_READ | VM_MAYREAD | VM_EXEC | VM_MAYEXEC; + gate_vma.vm_page_prot = __P101; + + /* + * Make sure the vDSO gets into every core dump. + * Dumping its contents makes post-mortem fully interpretable later + * without matching up the same kernel and hardware config to see + * what PC values meant. + */ + gate_vma.vm_flags |= VM_ALWAYSDUMP; + + return 0; +} +__initcall(gate_vma_init); + +struct vm_area_struct *get_gate_vma(struct mm_struct *mm) +{ + return FIXADDR_USER_START ? &gate_vma : NULL; +} + +int in_gate_area_no_mm(unsigned long addr) +{ + if (!FIXADDR_USER_START) + return 0; + + if ((addr >= FIXADDR_USER_START) && (addr < FIXADDR_USER_END)) + return 1; + + return 0; +} + +int in_gate_area(struct mm_struct *mm, unsigned long addr) +{ + struct vm_area_struct *vma = get_gate_vma(mm); + + if (!vma) + return 0; + + return (addr >= vma->vm_start) && (addr < vma->vm_end); +} -- 1.7.6