linux 2.6.16.38 w/ vs2.0.3-rc1

[linux-2.6.git] / arch / ia64 / kernel / signal.c

diff --git a/arch/ia64/kernel/signal.c b/arch/ia64/kernel/signal.c
index 77f8b49..0b00de6 100644 (file)
--- a/arch/ia64/kernel/signal.c
+++ b/arch/ia64/kernel/signal.c
@@ -7,6 +7,7 @@
  * Derived from i386 and Alpha versions.
  */
 
+#include <linux/config.h>
 #include <linux/errno.h>
 #include <linux/kernel.h>
 #include <linux/mm.h>
@@ -20,6 +21,7 @@
 #include <linux/binfmts.h>
 #include <linux/unistd.h>
 #include <linux/wait.h>
+#include <linux/vs_cvirt.h>
 
 #include <asm/ia32.h>
 #include <asm/intrinsics.h>
@@ -587,3 +589,104 @@ ia64_do_signal (sigset_t *oldset, struct sigscratch *scr, long in_syscall)
        }
        return 0;
 }
+
+/* Set a delayed signal that was detected in MCA/INIT/NMI/PMI context where it
+ * could not be delivered.  It is important that the target process is not
+ * allowed to do any more work in user space.  Possible cases for the target
+ * process:
+ *
+ * - It is sleeping and will wake up soon.  Store the data in the current task,
+ *   the signal will be sent when the current task returns from the next
+ *   interrupt.
+ *
+ * - It is running in user context.  Store the data in the current task, the
+ *   signal will be sent when the current task returns from the next interrupt.
+ *
+ * - It is running in kernel context on this or another cpu and will return to
+ *   user context.  Store the data in the target task, the signal will be sent
+ *   to itself when the target task returns to user space.
+ *
+ * - It is running in kernel context on this cpu and will sleep before
+ *   returning to user context.  Because this is also the current task, the
+ *   signal will not get delivered and the task could sleep indefinitely.
+ *   Store the data in the idle task for this cpu, the signal will be sent
+ *   after the idle task processes its next interrupt.
+ *
+ * To cover all cases, store the data in the target task, the current task and
+ * the idle task on this cpu.  Whatever happens, the signal will be delivered
+ * to the target task before it can do any useful user space work.  Multiple
+ * deliveries have no unwanted side effects.
+ *
+ * Note: This code is executed in MCA/INIT/NMI/PMI context, with interrupts
+ * disabled.  It must not take any locks nor use kernel structures or services
+ * that require locks.
+ */
+
+/* To ensure that we get the right pid, check its start time.  To avoid extra
+ * include files in thread_info.h, convert the task start_time to unsigned long,
+ * giving us a cycle time of > 580 years.
+ */
+static inline unsigned long
+start_time_ul(const struct task_struct *t)
+{
+       return t->start_time.tv_sec * NSEC_PER_SEC + t->start_time.tv_nsec;
+}
+
+void
+set_sigdelayed(pid_t pid, int signo, int code, void __user *addr)
+{
+       struct task_struct *t;
+       unsigned long start_time =  0;
+       int i;
+
+       for (i = 1; i <= 3; ++i) {
+               switch (i) {
+               case 1:
+                       t = find_task_by_pid(pid);
+                       if (t)
+                               start_time = start_time_ul(t);
+                       break;
+               case 2:
+                       t = current;
+                       break;
+               default:
+                       t = idle_task(smp_processor_id());
+                       break;
+               }
+
+               if (!t)
+                       return;
+               task_thread_info(t)->sigdelayed.signo = signo;
+               task_thread_info(t)->sigdelayed.code = code;
+               task_thread_info(t)->sigdelayed.addr = addr;
+               task_thread_info(t)->sigdelayed.start_time = start_time;
+               task_thread_info(t)->sigdelayed.pid = pid;
+               wmb();
+               set_tsk_thread_flag(t, TIF_SIGDELAYED);
+       }
+}
+
+/* Called from entry.S when it detects TIF_SIGDELAYED, a delayed signal that
+ * was detected in MCA/INIT/NMI/PMI context where it could not be delivered.
+ */
+
+void
+do_sigdelayed(void)
+{
+       struct siginfo siginfo;
+       pid_t pid;
+       struct task_struct *t;
+
+       clear_thread_flag(TIF_SIGDELAYED);
+       memset(&siginfo, 0, sizeof(siginfo));
+       siginfo.si_signo = current_thread_info()->sigdelayed.signo;
+       siginfo.si_code = current_thread_info()->sigdelayed.code;
+       siginfo.si_addr = current_thread_info()->sigdelayed.addr;
+       pid = current_thread_info()->sigdelayed.pid;
+       t = find_task_by_pid(pid);
+       if (!t)
+               return;
+       if (current_thread_info()->sigdelayed.start_time != start_time_ul(t))
+               return;
+       force_sig_info(siginfo.si_signo, &siginfo, t);
+}