From mboxrd@z Thu Jan 1 00:00:00 1970 From: Catalin Marinas Subject: Re: [PATCH v3 07/13] task_isolation: arch/arm64: enable task isolation functionality Date: Wed, 22 Apr 2020 13:08:12 +0100 Message-ID: <20200422120811.GA3585@gaia> References: <07c25c246c55012981ec0296eee23e68c719333a.camel@marvell.com> <299c02b268a6438704693ddb77cdcb49f382c0ea.camel@marvell.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from foss.arm.com ([217.140.110.172]:48626 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726110AbgDVMIR (ORCPT ); Wed, 22 Apr 2020 08:08:17 -0400 Content-Disposition: inline In-Reply-To: <299c02b268a6438704693ddb77cdcb49f382c0ea.camel@marvell.com> Sender: linux-arch-owner@vger.kernel.org List-ID: To: Alex Belits Cc: "frederic@kernel.org" , "rostedt@goodmis.org" , Prasun Kapoor , "mingo@kernel.org" , "davem@davemloft.net" , "linux-api@vger.kernel.org" , "peterz@infradead.org" , "linux-arch@vger.kernel.org" , "tglx@linutronix.de" , "will@kernel.org" , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" , "netdev@vger.kernel.org" On Thu, Apr 09, 2020 at 03:23:35PM +0000, Alex Belits wrote: > diff --git a/arch/arm64/include/asm/thread_info.h b/arch/arm64/include/asm/thread_info.h > index f0cec4160136..7563098eb5b2 100644 > --- a/arch/arm64/include/asm/thread_info.h > +++ b/arch/arm64/include/asm/thread_info.h > @@ -63,6 +63,7 @@ void arch_release_task_struct(struct task_struct *tsk); > #define TIF_FOREIGN_FPSTATE 3 /* CPU's FP state is not current's */ > #define TIF_UPROBE 4 /* uprobe breakpoint or singlestep */ > #define TIF_FSCHECK 5 /* Check FS is USER_DS on return */ > +#define TIF_TASK_ISOLATION 6 > #define TIF_NOHZ 7 > #define TIF_SYSCALL_TRACE 8 /* syscall trace active */ > #define TIF_SYSCALL_AUDIT 9 /* syscall auditing */ > @@ -83,6 +84,7 @@ void arch_release_task_struct(struct task_struct *tsk); > #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) > @@ -96,7 +98,8 @@ void arch_release_task_struct(struct task_struct *tsk); > > #define _TIF_WORK_MASK (_TIF_NEED_RESCHED | _TIF_SIGPENDING | \ > _TIF_NOTIFY_RESUME | _TIF_FOREIGN_FPSTATE | \ > - _TIF_UPROBE | _TIF_FSCHECK) > + _TIF_UPROBE | _TIF_FSCHECK | \ > + _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 cd6e5fa48b9c..b35b9b0c594c 100644 > --- a/arch/arm64/kernel/ptrace.c > +++ b/arch/arm64/kernel/ptrace.c > @@ -29,6 +29,7 @@ > #include > #include > #include > +#include > > #include > #include > @@ -1836,6 +1837,15 @@ int syscall_trace_enter(struct pt_regs *regs) > return -1; > } > > + /* > + * In task isolation mode, we may prevent the syscall from > + * running, and if so we also deliver a signal to the process. > + */ > + if (test_thread_flag(TIF_TASK_ISOLATION)) { > + if (task_isolation_syscall(regs->syscallno) == -1) > + return -1; > + } Is this supposed to be called only when syscall tracing is enabled? It only gets here if the task has any of the _TIF_SYSCALL_WORK flags. > diff --git a/arch/arm64/kernel/signal.c b/arch/arm64/kernel/signal.c > index 339882db5a91..d488c91a4877 100644 > --- a/arch/arm64/kernel/signal.c > +++ b/arch/arm64/kernel/signal.c > @@ -20,6 +20,7 @@ > #include > #include > #include > +#include > > #include > #include > @@ -898,6 +899,11 @@ static void do_signal(struct pt_regs *regs) > restore_saved_sigmask(); > } > > +#define NOTIFY_RESUME_LOOP_FLAGS \ > + (_TIF_NEED_RESCHED | _TIF_SIGPENDING | \ > + _TIF_NOTIFY_RESUME | _TIF_FOREIGN_FPSTATE | \ > + _TIF_UPROBE | _TIF_FSCHECK) AFAICT, that's just _TIF_WORK_MASK without _TIF_TASK_ISOLATION. I'd rather not duplicate these, they are prone to get out of sync. You could do something like: #define NOTIFY_RESUME_LOOP_FLAGS (_TIF_WORK_MASK & ~_TIF_TASK_ISOLATION) > + > asmlinkage void do_notify_resume(struct pt_regs *regs, > unsigned long thread_flags) > { > @@ -908,6 +914,8 @@ asmlinkage void do_notify_resume(struct pt_regs *regs, > */ > trace_hardirqs_off(); > > + task_isolation_check_run_cleanup(); > + > do { > /* Check valid user FS if needed */ > addr_limit_user_check(); > @@ -938,7 +946,10 @@ asmlinkage void do_notify_resume(struct pt_regs *regs, > > local_daif_mask(); > thread_flags = READ_ONCE(current_thread_info()->flags); > - } while (thread_flags & _TIF_WORK_MASK); > + } while (thread_flags & NOTIFY_RESUME_LOOP_FLAGS); > + > + if (thread_flags & _TIF_TASK_ISOLATION) > + task_isolation_start(); > } > > unsigned long __ro_after_init signal_minsigstksz; -- Catalin