fork: Add generic vmalloced stack support

[cascardo/linux.git] / include / linux / sched.h

diff --git a/include/linux/sched.h b/include/linux/sched.h
index 553af29..20f9f47 100644 (file)
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1547,6 +1547,9 @@ struct task_struct {
        /* unserialized, strictly 'current' */
        unsigned in_execve:1; /* bit to tell LSMs we're in execve */
        unsigned in_iowait:1;
+#if !defined(TIF_RESTORE_SIGMASK)
+       unsigned restore_sigmask:1;
+#endif
 #ifdef CONFIG_MEMCG
        unsigned memcg_may_oom:1;
 #ifndef CONFIG_SLOB
@@ -1920,6 +1923,9 @@ struct task_struct {
 #ifdef CONFIG_MMU
        struct task_struct *oom_reaper_list;
 #endif
+#ifdef CONFIG_VMAP_STACK
+       struct vm_struct *stack_vm_area;
+#endif
 /* CPU-specific state of this task */
        struct thread_struct thread;
 /*
@@ -1936,6 +1942,18 @@ extern int arch_task_struct_size __read_mostly;
 # define arch_task_struct_size (sizeof(struct task_struct))
 #endif
 
+#ifdef CONFIG_VMAP_STACK
+static inline struct vm_struct *task_stack_vm_area(const struct task_struct *t)
+{
+       return t->stack_vm_area;
+}
+#else
+static inline struct vm_struct *task_stack_vm_area(const struct task_struct *t)
+{
+       return NULL;
+}
+#endif
+
 /* Future-safe accessor for struct task_struct's cpus_allowed. */
 #define tsk_cpus_allowed(tsk) (&(tsk)->cpus_allowed)
 
@@ -2680,6 +2698,66 @@ extern void sigqueue_free(struct sigqueue *);
 extern int send_sigqueue(struct sigqueue *,  struct task_struct *, int group);
 extern int do_sigaction(int, struct k_sigaction *, struct k_sigaction *);
 
+#ifdef TIF_RESTORE_SIGMASK
+/*
+ * Legacy restore_sigmask accessors.  These are inefficient on
+ * SMP architectures because they require atomic operations.
+ */
+
+/**
+ * set_restore_sigmask() - make sure saved_sigmask processing gets done
+ *
+ * This sets TIF_RESTORE_SIGMASK and ensures that the arch signal code
+ * will run before returning to user mode, to process the flag.  For
+ * all callers, TIF_SIGPENDING is already set or it's no harm to set
+ * it.  TIF_RESTORE_SIGMASK need not be in the set of bits that the
+ * arch code will notice on return to user mode, in case those bits
+ * are scarce.  We set TIF_SIGPENDING here to ensure that the arch
+ * signal code always gets run when TIF_RESTORE_SIGMASK is set.
+ */
+static inline void set_restore_sigmask(void)
+{
+       set_thread_flag(TIF_RESTORE_SIGMASK);
+       WARN_ON(!test_thread_flag(TIF_SIGPENDING));
+}
+static inline void clear_restore_sigmask(void)
+{
+       clear_thread_flag(TIF_RESTORE_SIGMASK);
+}
+static inline bool test_restore_sigmask(void)
+{
+       return test_thread_flag(TIF_RESTORE_SIGMASK);
+}
+static inline bool test_and_clear_restore_sigmask(void)
+{
+       return test_and_clear_thread_flag(TIF_RESTORE_SIGMASK);
+}
+
+#else  /* TIF_RESTORE_SIGMASK */
+
+/* Higher-quality implementation, used if TIF_RESTORE_SIGMASK doesn't exist. */
+static inline void set_restore_sigmask(void)
+{
+       current->restore_sigmask = true;
+       WARN_ON(!test_thread_flag(TIF_SIGPENDING));
+}
+static inline void clear_restore_sigmask(void)
+{
+       current->restore_sigmask = false;
+}
+static inline bool test_restore_sigmask(void)
+{
+       return current->restore_sigmask;
+}
+static inline bool test_and_clear_restore_sigmask(void)
+{
+       if (!current->restore_sigmask)
+               return false;
+       current->restore_sigmask = false;
+       return true;
+}
+#endif
+
 static inline void restore_saved_sigmask(void)
 {
        if (test_and_clear_restore_sigmask())