Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal

Pull first series of signal handling cleanups from Al Viro:
 "This is just the first part of the queue (about a half of it);
  assorted fixes all over the place in signal handling.

  This one ends with all sigsuspend() implementations switched to
  generic one (->saved_sigmask-based).

  With this, a bunch of assorted old buglets are fixed and most of the
  missing bits of NOTIFY_RESUME hookup are in place.  Two more fixes sit
  in arm and um trees respectively, and there's a couple of broken ones
  that need obvious fixes - parisc and avr32 check TIF_NOTIFY_RESUME
  only on one of two codepaths; fixes for that will happen in the next
  series"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal: (55 commits)
  unicore32: if there's no handler we need to restore sigmask, syscall or no syscall
  xtensa: add handling of TIF_NOTIFY_RESUME
  microblaze: drop 'oldset' argument of do_notify_resume()
  microblaze: handle TIF_NOTIFY_RESUME
  score: add handling of NOTIFY_RESUME to do_notify_resume()
  m68k: add TIF_NOTIFY_RESUME and handle it.
  sparc: kill ancient comment in sparc_sigaction()
  h8300: missing checks of __get_user()/__put_user() return values
  frv: missing checks of __get_user()/__put_user() return values
  cris: missing checks of __get_user()/__put_user() return values
  powerpc: missing checks of __get_user()/__put_user() return values
  sh: missing checks of __get_user()/__put_user() return values
  sparc: missing checks of __get_user()/__put_user() return values
  avr32: struct old_sigaction is never used
  m32r: struct old_sigaction is never used
  xtensa: xtensa_sigaction doesn't exist
  alpha: tidy signal delivery up
  score: don't open-code force_sigsegv()
  cris: don't open-code force_sigsegv()
  blackfin: don't open-code force_sigsegv()
  ...

2 files changed, 35 insertions, 44 deletions

diff --git a/arch/xtensa/kernel/entry.S b/arch/xtensa/kernel/entry.S
index 6223f3346b5c..7e6236073397 100644
--- a/arch/xtensa/kernel/entry.S
+++ b/arch/xtensa/kernel/entry.S
@@ -409,16 +409,16 @@ common_exception_return:
         l32i    a4, a2, TI_FLAGS
 
         _bbsi.l a4, TIF_NEED_RESCHED, 3f
+        _bbsi.l a4, TIF_NOTIFY_RESUME, 2f
         _bbci.l a4, TIF_SIGPENDING, 4f
 
-        l32i    a4, a1, PT_DEPC
+2:      l32i    a4, a1, PT_DEPC
         bgeui   a4, VALID_DOUBLE_EXCEPTION_ADDRESS, 4f
 
         /* Call do_signal() */
 
-        movi    a4, do_signal   # int do_signal(struct pt_regs*, sigset_t*)
+        movi    a4, do_notify_resume    # int do_notify_resume(struct pt_regs*)
         mov     a6, a1
-        movi    a7, 0
         callx4  a4
         j       1b
 
diff --git a/arch/xtensa/kernel/signal.c b/arch/xtensa/kernel/signal.c
index d78869a00b11..c5e4ec0598d2 100644
--- a/arch/xtensa/kernel/signal.c
+++ b/arch/xtensa/kernel/signal.c
@@ -20,6 +20,7 @@
 #include <linux/ptrace.h>
 #include <linux/personality.h>
 #include <linux/freezer.h>
+#include <linux/tracehook.h>
 
 #include <asm/ucontext.h>
 #include <asm/uaccess.h>
@@ -31,8 +32,6 @@
 
 #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
 
-asmlinkage int do_signal(struct pt_regs *regs, sigset_t *oldset);
-
 extern struct task_struct *coproc_owners[];
 
 struct rt_sigframe
@@ -248,6 +247,9 @@ asmlinkage long xtensa_rt_sigreturn(long a0, long a1, long a2, long a3,
         sigset_t set;
         int ret;
 
+        /* Always make any pending restarted system calls return -EINTR */
+        current_thread_info()->restart_block.fn = do_no_restart_syscall;
+
         if (regs->depc > 64)
                 panic("rt_sigreturn in double exception!\n");
 
@@ -426,37 +428,6 @@ give_sigsegv:
         return -EFAULT;
 }
 
-/*
- * Atomically swap in the new signal mask, and wait for a signal.
- */
-
-asmlinkage long xtensa_rt_sigsuspend(sigset_t __user *unewset, 
-                                     size_t sigsetsize,
-                                     long a2, long a3, long a4, long a5, 
-                                     struct pt_regs *regs)
-{
-        sigset_t saveset, newset;
-
-        /* XXX: Don't preclude handling different sized sigset_t's.  */
-        if (sigsetsize != sizeof(sigset_t))
-                return -EINVAL;
-
-        if (copy_from_user(&newset, unewset, sizeof(newset)))
-                return -EFAULT;
-
-        sigdelsetmask(&newset, ~_BLOCKABLE);
-        saveset = current->blocked;
-        set_current_blocked(&newset);
-
-        regs->areg[2] = -EINTR;
-        while (1) {
-                current->state = TASK_INTERRUPTIBLE;
-                schedule();
-                if (do_signal(regs, &saveset))
-                        return -EINTR;
-        }
-}
-
 asmlinkage long xtensa_sigaltstack(const stack_t __user *uss, 
                                    stack_t __user *uoss,
                                    long a2, long a3, long a4, long a5,
@@ -476,19 +447,19 @@ asmlinkage long xtensa_sigaltstack(const stack_t __user *uss,
  * the kernel can handle, and then we build all the user-level signal handling
  * stack-frames in one go after that.
  */
-int do_signal(struct pt_regs *regs, sigset_t *oldset)
+static void do_signal(struct pt_regs *regs)
 {
         siginfo_t info;
         int signr;
         struct k_sigaction ka;
-
-        if (!user_mode(regs))
-                return 0;
+        sigset_t oldset;
 
         if (try_to_freeze())
                 goto no_signal;
 
-        if (!oldset)
+        if (test_thread_flag(TIF_RESTORE_SIGMASK))
+                oldset = &current->saved_sigmask;
+        else
                 oldset = &current->blocked;
 
         task_pt_regs(current)->icountlevel = 0;
@@ -532,13 +503,14 @@ int do_signal(struct pt_regs *regs, sigset_t *oldset)
                 /* Set up the stack frame */
                 ret = setup_frame(signr, &ka, &info, oldset, regs);
                 if (ret)
-                        return ret;
+                        return;
 
+                clear_thread_flag(TIF_RESTORE_SIGMASK);
                 block_sigmask(&ka, signr);
                 if (current->ptrace & PT_SINGLESTEP)
                         task_pt_regs(current)->icountlevel = 1;
 
-                return 1;
+                return;
         }
 
 no_signal:
@@ -558,8 +530,27 @@ no_signal:
                         break;
                 }
         }
+
+        /* If there's no signal to deliver, we just restore the saved mask.  */
+        if (test_and_clear_thread_flag(TIF_RESTORE_SIGMASK))
+                set_current_blocked(&current->saved_sigmask);
+
         if (current->ptrace & PT_SINGLESTEP)
                 task_pt_regs(current)->icountlevel = 1;
-        return 0;
+        return;
 }
 
+void do_notify_resume(struct pt_regs *regs)
+{
+        if (!user_mode(regs))
+                return;
+
+        if (test_thread_flag(TIF_SIGPENDING))
+                do_signal(regs);
+
+        if (test_and_clear_thread_flag(TIF_NOTIFY_RESUME)) {
+                tracehook_notify_resume(regs);
+                if (current->replacement_session_keyring)
+                        key_replace_session_keyring();
+        }
+}