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Date: Wed, 2 Mar 2016 15:09:36 -0500
From: Chris Metcalf <cmetcalf@...hip.com>
To: Gilad Ben Yossef <giladb@...hip.com>,
Steven Rostedt <rostedt@...dmis.org>,
Ingo Molnar <mingo@...nel.org>,
Peter Zijlstra <peterz@...radead.org>,
Andrew Morton <akpm@...ux-foundation.org>,
"Rik van Riel" <riel@...hat.com>, Tejun Heo <tj@...nel.org>,
Frederic Weisbecker <fweisbec@...il.com>,
Thomas Gleixner <tglx@...utronix.de>,
"Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>,
Christoph Lameter <cl@...ux.com>,
Viresh Kumar <viresh.kumar@...aro.org>,
Catalin Marinas <catalin.marinas@....com>,
Will Deacon <will.deacon@....com>,
Andy Lutomirski <luto@...capital.net>,
Mark Rutland <mark.rutland@....com>,
<linux-arm-kernel@...ts.infradead.org>,
<linux-kernel@...r.kernel.org>
CC: Chris Metcalf <cmetcalf@...hip.com>
Subject: [PATCH v10 12/12] arch/arm64: enable task isolation functionality
In do_notify_resume(), call task_isolation_ready() when we are
checking the thread-info flags; and after we've handled the other
work, call task_isolation_enter() unconditionally. To ensure we
always call task_isolation_enter() when returning to userspace,
modify _TIF_WORK_MASK to be _TIF_NOHZ, which is set in every task,
when we build with TASK_ISOLATION configured.
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_cross_call() 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, add an explicit check for STRICT mode in do_mem_abort()
to handle the case of page faults.
Signed-off-by: Chris Metcalf <cmetcalf@...hip.com>
---
arch/arm64/include/asm/thread_info.h | 8 +++++++-
arch/arm64/kernel/ptrace.c | 12 +++++++++---
arch/arm64/kernel/signal.c | 6 +++++-
arch/arm64/kernel/smp.c | 2 ++
arch/arm64/mm/fault.c | 4 ++++
5 files changed, 27 insertions(+), 5 deletions(-)
diff --git a/arch/arm64/include/asm/thread_info.h b/arch/arm64/include/asm/thread_info.h
index abd64bd1f6d9..89c72888cb54 100644
--- a/arch/arm64/include/asm/thread_info.h
+++ b/arch/arm64/include/asm/thread_info.h
@@ -131,9 +131,15 @@ static inline struct thread_info *current_thread_info(void)
#define _TIF_SECCOMP (1 << TIF_SECCOMP)
#define _TIF_32BIT (1 << TIF_32BIT)
-#define _TIF_WORK_MASK (_TIF_NEED_RESCHED | _TIF_SIGPENDING | \
+#define _TIF_WORK_LOOP_MASK (_TIF_NEED_RESCHED | _TIF_SIGPENDING | \
_TIF_NOTIFY_RESUME | _TIF_FOREIGN_FPSTATE)
+#ifdef CONFIG_TASK_ISOLATION
+# define _TIF_WORK_MASK _TIF_NOHZ /* always set */
+#else
+# define _TIF_WORK_MASK _TIF_WORK_LOOP_MASK
+#endif
+
#define _TIF_SYSCALL_WORK (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | \
_TIF_SYSCALL_TRACEPOINT | _TIF_SECCOMP | \
_TIF_NOHZ)
diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c
index ff7f13239515..43aa6d016f46 100644
--- a/arch/arm64/kernel/ptrace.c
+++ b/arch/arm64/kernel/ptrace.c
@@ -37,6 +37,7 @@
#include <linux/regset.h>
#include <linux/tracehook.h>
#include <linux/elf.h>
+#include <linux/isolation.h>
#include <asm/compat.h>
#include <asm/debug-monitors.h>
@@ -1246,14 +1247,19 @@ static void tracehook_report_syscall(struct pt_regs *regs,
asmlinkage int syscall_trace_enter(struct pt_regs *regs)
{
- /* Do the secure computing check first; failures should be fast. */
+ unsigned long work = ACCESS_ONCE(current_thread_info()->flags);
+
+ if ((work & _TIF_NOHZ) && task_isolation_check_syscall(regs->syscallno))
+ return -1;
+
+ /* Do the secure computing check early; failures should be fast. */
if (secure_computing() == -1)
return -1;
- if (test_thread_flag(TIF_SYSCALL_TRACE))
+ if (work & _TIF_SYSCALL_TRACE)
tracehook_report_syscall(regs, PTRACE_SYSCALL_ENTER);
- 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 3432e14b7d6e..53fcd6c305d6 100644
--- a/arch/arm64/kernel/signal.c
+++ b/arch/arm64/kernel/signal.c
@@ -25,6 +25,7 @@
#include <linux/uaccess.h>
#include <linux/tracehook.h>
#include <linux/ratelimit.h>
+#include <linux/isolation.h>
#include <asm/debug-monitors.h>
#include <asm/elf.h>
@@ -419,12 +420,15 @@ asmlinkage void do_notify_resume(struct pt_regs *regs,
if (thread_flags & _TIF_FOREIGN_FPSTATE)
fpsimd_restore_current_state();
+
+ task_isolation_enter();
}
local_irq_disable();
thread_flags = READ_ONCE(current_thread_info()->flags);
- if (!(thread_flags & _TIF_WORK_MASK))
+ if (!(thread_flags & _TIF_WORK_LOOP_MASK) &&
+ task_isolation_ready())
break;
}
}
diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c
index b1adc51b2c2e..dcb3282d04a2 100644
--- a/arch/arm64/kernel/smp.c
+++ b/arch/arm64/kernel/smp.c
@@ -37,6 +37,7 @@
#include <linux/completion.h>
#include <linux/of.h>
#include <linux/irq_work.h>
+#include <linux/isolation.h>
#include <asm/alternative.h>
#include <asm/atomic.h>
@@ -632,6 +633,7 @@ static const char *ipi_types[NR_IPI] __tracepoint_string = {
static void smp_cross_call(const struct cpumask *target, unsigned int ipinr)
{
trace_ipi_raise(target, ipi_types[ipinr]);
+ task_isolation_debug_cpumask(target);
__smp_cross_call(target, ipinr);
}
diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c
index abe2a9542b3a..644cd634dd1d 100644
--- a/arch/arm64/mm/fault.c
+++ b/arch/arm64/mm/fault.c
@@ -29,6 +29,7 @@
#include <linux/sched.h>
#include <linux/highmem.h>
#include <linux/perf_event.h>
+#include <linux/isolation.h>
#include <asm/cpufeature.h>
#include <asm/exception.h>
@@ -473,6 +474,9 @@ asmlinkage void __exception do_mem_abort(unsigned long addr, unsigned int esr,
const struct fault_info *inf = fault_info + (esr & 63);
struct siginfo info;
+ if (user_mode(regs))
+ task_isolation_check_exception("%s at %#lx", inf->name, addr);
+
if (!inf->fn(addr, esr, regs))
return;
--
2.1.2
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