From patchwork Tue Aug 9 20:29:50 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chris Metcalf X-Patchwork-Id: 9272187 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id BA61160231 for ; Tue, 9 Aug 2016 20:33:00 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id B9B1328389 for ; Tue, 9 Aug 2016 20:33:00 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id ADED4283EE; Tue, 9 Aug 2016 20:33:00 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.2 required=2.0 tests=BAYES_00, RCVD_IN_DNSWL_MED, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.9]) (using TLSv1.2 with cipher AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 3FC08283E5 for ; Tue, 9 Aug 2016 20:33:00 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.85_2 #1 (Red Hat Linux)) id 1bXDfx-00056w-69; Tue, 09 Aug 2016 20:31:01 +0000 Received: from mail-il-dmz.mellanox.com ([193.47.165.129] helo=mellanox.co.il) by bombadil.infradead.org with esmtp (Exim 4.85_2 #1 (Red Hat Linux)) id 1bXDfb-0004Qa-2t for linux-arm-kernel@lists.infradead.org; Tue, 09 Aug 2016 20:30:42 +0000 Received: from Internal Mail-Server by MTLPINE1 (envelope-from cmetcalf@mellanox.com) with ESMTPS (AES256-SHA encrypted); 9 Aug 2016 23:30:12 +0300 Received: from ld-1.internal.tilera.com (ld-1.internal.tilera.com [10.15.7.41]) by mtbu-labmail01.internal.tilera.com (8.14.4/8.14.4) with ESMTP id u79KUBwJ005397; Tue, 9 Aug 2016 16:30:11 -0400 Received: (from cmetcalf@localhost) by ld-1.internal.tilera.com (8.14.4/8.14.4/Submit) id u79KUBL6017418; Tue, 9 Aug 2016 16:30:11 -0400 From: Chris Metcalf To: Gilad Ben Yossef , Steven Rostedt , Ingo Molnar , Peter Zijlstra , Andrew Morton , Rik van Riel , Tejun Heo , Frederic Weisbecker , Thomas Gleixner , "Paul E. McKenney" , Christoph Lameter , Viresh Kumar , Catalin Marinas , Will Deacon , Andy Lutomirski , Mark Rutland , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: [PATCH v14 08/14] arch/arm64: enable task isolation functionality Date: Tue, 9 Aug 2016 16:29:50 -0400 Message-Id: <1470774596-17341-9-git-send-email-cmetcalf@mellanox.com> X-Mailer: git-send-email 2.7.2 In-Reply-To: <1470774596-17341-1-git-send-email-cmetcalf@mellanox.com> References: <1470774596-17341-1-git-send-email-cmetcalf@mellanox.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20160809_133039_640134_07F79E42 X-CRM114-Status: GOOD ( 17.72 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Chris Metcalf MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Virus-Scanned: ClamAV using ClamSMTP In do_notify_resume(), call task_isolation_ready() for TIF_TASK_ISOLATION tasks when we are checking the thread-info flags; and after we've handled the other work, call task_isolation_enter() for such tasks. To ensure we always call task_isolation_enter() when returning to userspace, add _TIF_TASK_ISOLATION to _TIF_WORK_MASK, while leaving the old bitmask value as _TIF_WORK_LOOP_MASK to check while looping. We tweak syscall_trace_enter() slightly to carry the "flags" value from current_thread_info()->flags for each of the tests, rather than doing a volatile read from memory for each one. This avoids a small overhead for each test, and in particular avoids that overhead for TIF_NOHZ when TASK_ISOLATION is not enabled. We instrument the smp_send_reschedule() routine so that it checks for isolated tasks and generates a suitable warning if we are about to disturb one of them in strict or debug mode. Finally, report on page faults in task-isolation processes in do_page_faults(). Signed-off-by: Chris Metcalf --- arch/arm64/Kconfig | 1 + arch/arm64/include/asm/thread_info.h | 5 ++++- arch/arm64/kernel/ptrace.c | 15 ++++++++++++--- arch/arm64/kernel/signal.c | 10 ++++++++++ arch/arm64/kernel/smp.c | 2 ++ arch/arm64/mm/fault.c | 8 +++++++- 6 files changed, 36 insertions(+), 5 deletions(-) diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 69c8787bec7d..1aea9a329b85 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -61,6 +61,7 @@ config ARM64 select HAVE_ARCH_MMAP_RND_BITS select HAVE_ARCH_MMAP_RND_COMPAT_BITS if COMPAT select HAVE_ARCH_SECCOMP_FILTER + select HAVE_ARCH_TASK_ISOLATION select HAVE_ARCH_TRACEHOOK select HAVE_ARCH_TRANSPARENT_HUGEPAGE select HAVE_ARM_SMCCC diff --git a/arch/arm64/include/asm/thread_info.h b/arch/arm64/include/asm/thread_info.h index abd64bd1f6d9..bdc6426b9968 100644 --- a/arch/arm64/include/asm/thread_info.h +++ b/arch/arm64/include/asm/thread_info.h @@ -109,6 +109,7 @@ static inline struct thread_info *current_thread_info(void) #define TIF_NEED_RESCHED 1 #define TIF_NOTIFY_RESUME 2 /* callback before returning to user */ #define TIF_FOREIGN_FPSTATE 3 /* CPU's FP state is not current's */ +#define TIF_TASK_ISOLATION 4 #define TIF_NOHZ 7 #define TIF_SYSCALL_TRACE 8 #define TIF_SYSCALL_AUDIT 9 @@ -124,6 +125,7 @@ static inline struct thread_info *current_thread_info(void) #define _TIF_NEED_RESCHED (1 << TIF_NEED_RESCHED) #define _TIF_NOTIFY_RESUME (1 << TIF_NOTIFY_RESUME) #define _TIF_FOREIGN_FPSTATE (1 << TIF_FOREIGN_FPSTATE) +#define _TIF_TASK_ISOLATION (1 << TIF_TASK_ISOLATION) #define _TIF_NOHZ (1 << TIF_NOHZ) #define _TIF_SYSCALL_TRACE (1 << TIF_SYSCALL_TRACE) #define _TIF_SYSCALL_AUDIT (1 << TIF_SYSCALL_AUDIT) @@ -132,7 +134,8 @@ static inline struct thread_info *current_thread_info(void) #define _TIF_32BIT (1 << TIF_32BIT) #define _TIF_WORK_MASK (_TIF_NEED_RESCHED | _TIF_SIGPENDING | \ - _TIF_NOTIFY_RESUME | _TIF_FOREIGN_FPSTATE) + _TIF_NOTIFY_RESUME | _TIF_FOREIGN_FPSTATE | \ + _TIF_TASK_ISOLATION) #define _TIF_SYSCALL_WORK (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | \ _TIF_SYSCALL_TRACEPOINT | _TIF_SECCOMP | \ diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c index e0c81da60f76..9b25ffb436cc 100644 --- a/arch/arm64/kernel/ptrace.c +++ b/arch/arm64/kernel/ptrace.c @@ -37,6 +37,7 @@ #include #include #include +#include #include #include @@ -1347,14 +1348,22 @@ static void tracehook_report_syscall(struct pt_regs *regs, asmlinkage int syscall_trace_enter(struct pt_regs *regs) { - if (test_thread_flag(TIF_SYSCALL_TRACE)) + unsigned long work = ACCESS_ONCE(current_thread_info()->flags); + + if (work & _TIF_SYSCALL_TRACE) tracehook_report_syscall(regs, PTRACE_SYSCALL_ENTER); - /* Do the secure computing after ptrace; failures should be fast. */ + /* In isolation mode, we may prevent the syscall from running. */ + if (work & _TIF_TASK_ISOLATION) { + if (task_isolation_syscall(regs->syscallno) == -1) + return -1; + } + + /* Do the secure computing check early; failures should be fast. */ if (secure_computing(NULL) == -1) return -1; - if (test_thread_flag(TIF_SYSCALL_TRACEPOINT)) + if (work & _TIF_SYSCALL_TRACEPOINT) trace_sys_enter(regs, regs->syscallno); audit_syscall_entry(regs->syscallno, regs->orig_x0, regs->regs[1], diff --git a/arch/arm64/kernel/signal.c b/arch/arm64/kernel/signal.c index 404dd67080b9..f9b9b25636ca 100644 --- a/arch/arm64/kernel/signal.c +++ b/arch/arm64/kernel/signal.c @@ -25,6 +25,7 @@ #include #include #include +#include #include #include @@ -424,9 +425,18 @@ asmlinkage void do_notify_resume(struct pt_regs *regs, if (thread_flags & _TIF_FOREIGN_FPSTATE) fpsimd_restore_current_state(); + + if (thread_flags & _TIF_TASK_ISOLATION) + task_isolation_enter(); } local_irq_disable(); thread_flags = READ_ONCE(current_thread_info()->flags); + + /* Clear task isolation from cached_flags manually. */ + if ((thread_flags & _TIF_TASK_ISOLATION) && + task_isolation_ready()) + thread_flags &= ~_TIF_TASK_ISOLATION; + } while (thread_flags & _TIF_WORK_MASK); } diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c index 76a6d9263908..ed75244014f5 100644 --- a/arch/arm64/kernel/smp.c +++ b/arch/arm64/kernel/smp.c @@ -37,6 +37,7 @@ #include #include #include +#include #include #include @@ -874,6 +875,7 @@ void handle_IPI(int ipinr, struct pt_regs *regs) void smp_send_reschedule(int cpu) { + task_isolation_debug(cpu, "reschedule IPI"); smp_cross_call(cpumask_of(cpu), IPI_RESCHEDULE); } diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c index c8beaa0da7df..f0c4d6ba346e 100644 --- a/arch/arm64/mm/fault.c +++ b/arch/arm64/mm/fault.c @@ -29,6 +29,7 @@ #include #include #include +#include #include #include @@ -382,8 +383,13 @@ retry: * Handle the "normal" case first - VM_FAULT_MAJOR */ if (likely(!(fault & (VM_FAULT_ERROR | VM_FAULT_BADMAP | - VM_FAULT_BADACCESS)))) + VM_FAULT_BADACCESS)))) { + /* No signal was generated, but notify task-isolation tasks. */ + if (user_mode(regs)) + task_isolation_quiet_exception("page fault at %#lx", + addr); return 0; + } /* * If we are in kernel mode at this point, we have no context to