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authorThomas Gleixner <tglx@linutronix.de>2022-03-31 10:36:55 +0200
committerThomas Gleixner <tglx@linutronix.de>2022-03-31 10:36:55 +0200
commit7dd5ad2d3e82fb55229e3fe18e09160878e77e20 (patch)
treeee452e1e6b8fb41a9b5e5339c7f152517567d376 /kernel
parent787af64d05cd528aac9ad16752d11bb1c6061bb9 (diff)
Revert "signal, x86: Delay calling signals in atomic on RT enabled kernels"
Revert commit bf9ad37dc8a. It needs to be better encapsulated and generalized. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/Kconfig.preempt12
-rw-r--r--kernel/entry/common.c14
-rw-r--r--kernel/signal.c40
3 files changed, 1 insertions, 65 deletions
diff --git a/kernel/Kconfig.preempt b/kernel/Kconfig.preempt
index 8c6de5a9ecc4..c2f1fd95a821 100644
--- a/kernel/Kconfig.preempt
+++ b/kernel/Kconfig.preempt
@@ -133,14 +133,4 @@ config SCHED_CORE
which is the likely usage by Linux distributions, there should
be no measurable impact on performance.
-config ARCH_WANTS_RT_DELAYED_SIGNALS
- bool
- help
- This option is selected by architectures where raising signals
- can happen in atomic contexts on PREEMPT_RT enabled kernels. This
- option delays raising the signal until the return to user space
- loop where it is also delivered. X86 requires this to deliver
- signals from trap handlers which run on IST stacks.
-
-config RT_DELAYED_SIGNALS
- def_bool PREEMPT_RT && ARCH_WANTS_RT_DELAYED_SIGNALS
+
diff --git a/kernel/entry/common.c b/kernel/entry/common.c
index ef8d94a98b7e..e57a224d6b79 100644
--- a/kernel/entry/common.c
+++ b/kernel/entry/common.c
@@ -142,18 +142,6 @@ void noinstr exit_to_user_mode(void)
/* Workaround to allow gradual conversion of architecture code */
void __weak arch_do_signal_or_restart(struct pt_regs *regs) { }
-#ifdef CONFIG_RT_DELAYED_SIGNALS
-static inline void raise_delayed_signal(void)
-{
- if (unlikely(current->forced_info.si_signo)) {
- force_sig_info(&current->forced_info);
- current->forced_info.si_signo = 0;
- }
-}
-#else
-static inline void raise_delayed_signal(void) { }
-#endif
-
static unsigned long exit_to_user_mode_loop(struct pt_regs *regs,
unsigned long ti_work)
{
@@ -168,8 +156,6 @@ static unsigned long exit_to_user_mode_loop(struct pt_regs *regs,
if (ti_work & _TIF_NEED_RESCHED)
schedule();
- raise_delayed_signal();
-
if (ti_work & _TIF_UPROBE)
uprobe_notify_resume(regs);
diff --git a/kernel/signal.c b/kernel/signal.c
index 368a34c25bbf..30cd1ca43bcd 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -1308,43 +1308,6 @@ enum sig_handler {
};
/*
- * On some archictectures, PREEMPT_RT has to delay sending a signal from a
- * trap since it cannot enable preemption, and the signal code's
- * spin_locks turn into mutexes. Instead, it must set TIF_NOTIFY_RESUME
- * which will send the signal on exit of the trap.
- */
-#ifdef CONFIG_RT_DELAYED_SIGNALS
-static inline bool force_sig_delayed(struct kernel_siginfo *info,
- struct task_struct *t)
-{
- if (!in_atomic())
- return false;
-
- if (WARN_ON_ONCE(t->forced_info.si_signo))
- return true;
-
- if (is_si_special(info)) {
- WARN_ON_ONCE(info != SEND_SIG_PRIV);
- t->forced_info.si_signo = info->si_signo;
- t->forced_info.si_errno = 0;
- t->forced_info.si_code = SI_KERNEL;
- t->forced_info.si_pid = 0;
- t->forced_info.si_uid = 0;
- } else {
- t->forced_info = *info;
- }
- set_tsk_thread_flag(t, TIF_NOTIFY_RESUME);
- return true;
-}
-#else
-static inline bool force_sig_delayed(struct kernel_siginfo *info,
- struct task_struct *t)
-{
- return false;
-}
-#endif
-
-/*
* Force a signal that the process can't ignore: if necessary
* we unblock the signal and change any SIG_IGN to SIG_DFL.
*
@@ -1364,9 +1327,6 @@ force_sig_info_to_task(struct kernel_siginfo *info, struct task_struct *t,
struct k_sigaction *action;
int sig = info->si_signo;
- if (force_sig_delayed(info, t))
- return 0;
-
spin_lock_irqsave(&t->sighand->siglock, flags);
action = &t->sighand->action[sig-1];
ignored = action->sa.sa_handler == SIG_IGN;