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authorJens Axboe <axboe@kernel.dk>2020-10-26 14:32:28 -0600
committerThomas Gleixner <tglx@linutronix.de>2020-10-29 09:37:36 +0100
commit12db8b690010ccfadf9d0b49a1e1798e47dbbe1a (patch)
tree185645b2e040fb94b3dfc06fae3c4f2ea8d734ad /kernel/entry
parent5c251e9dc0e127bac6fc5b8e6696363d2e35f515 (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/entry')
-rw-r--r--kernel/entry/common.c14
-rw-r--r--kernel/entry/kvm.c3
2 files changed, 14 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;