diff options
| author | Jens Axboe <axboe@kernel.dk> | 2020-10-26 14:32:28 -0600 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2020-10-29 09:37:36 +0100 |
| commit | 12db8b690010ccfadf9d0b49a1e1798e47dbbe1a (patch) | |
| tree | 185645b2e040fb94b3dfc06fae3c4f2ea8d734ad /kernel | |
| parent | 5c251e9dc0e127bac6fc5b8e6696363d2e35f515 (diff) | |
entry: Add support for TIF_NOTIFY_SIGNAL
Add TIF_NOTIFY_SIGNAL handling in the generic entry code, which if set,
will return true if signal_pending() is used in a wait loop. That causes an
exit of the loop so that notify_signal tracehooks can be run. If the wait
loop is currently inside a system call, the system call is restarted once
task_work has been processed.
In preparation for only having arch_do_signal() handle syscall restarts if
_TIF_SIGPENDING isn't set, rename it to arch_do_signal_or_restart(). Pass
in a boolean that tells the architecture specific signal handler if it
should attempt to get a signal, or just process a potential syscall
restart.
For !CONFIG_GENERIC_ENTRY archs, add the TIF_NOTIFY_SIGNAL handling to
get_signal(). This is done to minimize the needed architecture changes to
support this feature.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Link: https://lore.kernel.org/r/20201026203230.386348-3-axboe@kernel.dk
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/entry/common.c | 14 | ||||
| -rw-r--r-- | kernel/entry/kvm.c | 3 | ||||
| -rw-r--r-- | kernel/signal.c | 14 |
3 files changed, 28 insertions, 3 deletions
diff --git a/kernel/entry/common.c b/kernel/entry/common.c index 9852e0d62d95..42eff115c426 100644 --- a/kernel/entry/common.c +++ b/kernel/entry/common.c @@ -109,7 +109,15 @@ static __always_inline void exit_to_user_mode(void) } /* Workaround to allow gradual conversion of architecture code */ -void __weak arch_do_signal(struct pt_regs *regs) { } +void __weak arch_do_signal_or_restart(struct pt_regs *regs, bool has_signal) { } + +static void handle_signal_work(struct pt_regs *regs, unsigned long ti_work) +{ + if (ti_work & _TIF_NOTIFY_SIGNAL) + tracehook_notify_signal(); + + arch_do_signal_or_restart(regs, ti_work & _TIF_SIGPENDING); +} static unsigned long exit_to_user_mode_loop(struct pt_regs *regs, unsigned long ti_work) @@ -131,8 +139,8 @@ static unsigned long exit_to_user_mode_loop(struct pt_regs *regs, if (ti_work & _TIF_PATCH_PENDING) klp_update_patch_state(current); - if (ti_work & _TIF_SIGPENDING) - arch_do_signal(regs); + if (ti_work & (_TIF_SIGPENDING | _TIF_NOTIFY_SIGNAL)) + handle_signal_work(regs, ti_work); if (ti_work & _TIF_NOTIFY_RESUME) { clear_thread_flag(TIF_NOTIFY_RESUME); diff --git a/kernel/entry/kvm.c b/kernel/entry/kvm.c index eb1a8a4c867c..b828a3ddebf1 100644 --- a/kernel/entry/kvm.c +++ b/kernel/entry/kvm.c @@ -8,6 +8,9 @@ static int xfer_to_guest_mode_work(struct kvm_vcpu *vcpu, unsigned long ti_work) do { int ret; + if (ti_work & _TIF_NOTIFY_SIGNAL) + tracehook_notify_signal(); + if (ti_work & _TIF_SIGPENDING) { kvm_handle_signal_exit(vcpu); return -EINTR; diff --git a/kernel/signal.c b/kernel/signal.c index b179eccc86d0..61b377e65c46 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -2529,6 +2529,20 @@ bool get_signal(struct ksignal *ksig) struct signal_struct *signal = current->signal; int signr; + /* + * For non-generic architectures, check for TIF_NOTIFY_SIGNAL so + * that the arch handlers don't all have to do it. If we get here + * without TIF_SIGPENDING, just exit after running signal work. + */ +#ifdef TIF_NOTIFY_SIGNAL + if (!IS_ENABLED(CONFIG_GENERIC_ENTRY)) { + if (test_thread_flag(TIF_NOTIFY_SIGNAL)) + tracehook_notify_signal(); + if (!task_sigpending(current)) + return false; + } +#endif + if (unlikely(uprobe_deny_signal())) return false; |