@@ -62,6 +62,7 @@ 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
@@ -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 | \
@@ -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>
@@ -1347,14 +1348,25 @@ 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 task isolation mode, we may prevent the syscall from
+ * running, and if so we also deliver a signal to the process.
+ */
+ 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],
@@ -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>
@@ -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);
}
@@ -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>
@@ -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);
}
@@ -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>
@@ -392,8 +393,13 @@ 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
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 <cmetcalf@mellanox.com> --- arch/arm64/Kconfig | 1 + arch/arm64/include/asm/thread_info.h | 5 ++++- arch/arm64/kernel/ptrace.c | 18 +++++++++++++++--- arch/arm64/kernel/signal.c | 10 ++++++++++ arch/arm64/kernel/smp.c | 2 ++ arch/arm64/mm/fault.c | 8 +++++++- 6 files changed, 39 insertions(+), 5 deletions(-)