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()
  ...

3 files changed, 65 insertions, 70 deletions

diff --git a/arch/microblaze/kernel/entry-nommu.S b/arch/microblaze/kernel/entry-nommu.S
index 34b526f59b43..75c3ea1f48a1 100644
--- a/arch/microblaze/kernel/entry-nommu.S
+++ b/arch/microblaze/kernel/entry-nommu.S
@@ -132,11 +132,10 @@ ret_from_intr:
         beqi    r11, 1f
         bralid  r15, schedule
         nop
-1:      andi    r11, r19, _TIF_SIGPENDING
+1:      andi    r11, r19, _TIF_SIGPENDING | _TIF_NOTIFY_RESUME
         beqid   r11, no_intr_resched
         addk    r5, r1, r0
-        addk    r7, r0, r0
-        bralid  r15, do_signal
+        bralid  r15, do_notify_resume
         addk    r6, r0, r0
 
 no_intr_resched:
@@ -292,8 +291,8 @@ ENTRY(_user_exception)
 
 /*
  * Debug traps are like a system call, but entered via brki r14, 0x60
- * All we need to do is send the SIGTRAP signal to current, ptrace and do_signal
- * will handle the rest
+ * All we need to do is send the SIGTRAP signal to current, ptrace and
+ * do_notify_resume will handle the rest
  */
 ENTRY(_debug_exception)
         swi     r1, r0, PER_CPU(ENTRY_SP)       /* save the current sp */
@@ -482,12 +481,11 @@ work_pending:
         beqi    r11, 1f
         bralid  r15, schedule
         nop
-1:      andi    r11, r19, _TIF_SIGPENDING
+1:      andi    r11, r19, _TIF_SIGPENDING | _TIF_NOTIFY_RESUME
         beqi    r11, no_work_pending
         addk    r5, r1, r0
-        addik   r7, r0, 1
-        bralid  r15, do_signal
-        addk    r6, r0, r0
+        bralid  r15, do_notify_resume
+        addik   r6, r0, 1
         bri     no_work_pending
 
 ENTRY(ret_to_user)
@@ -569,10 +567,6 @@ sys_rt_sigreturn_wrapper:
         brid    sys_rt_sigreturn
         addk    r5, r1, r0
 
-sys_rt_sigsuspend_wrapper:
-        brid    sys_rt_sigsuspend
-        addk    r7, r1, r0
-
         /* Interrupt vector table */
         .section        .init.ivt, "ax"
         .org 0x0
diff --git a/arch/microblaze/kernel/entry.S b/arch/microblaze/kernel/entry.S
index 66e34a3bfe1b..daff9e5e4a1f 100644
--- a/arch/microblaze/kernel/entry.S
+++ b/arch/microblaze/kernel/entry.S
@@ -430,13 +430,12 @@ C_ENTRY(ret_from_trap):
 5:      /* get thread info from current task*/
         lwi     r11, CURRENT_TASK, TS_THREAD_INFO;
         lwi     r11, r11, TI_FLAGS;     /* get flags in thread info */
-        andi    r11, r11, _TIF_SIGPENDING;
+        andi    r11, r11, _TIF_SIGPENDING | _TIF_NOTIFY_RESUME;
         beqi    r11, 1f;                /* Signals to handle, handle them */
 
         addik   r5, r1, 0;              /* Arg 1: struct pt_regs *regs */
-        addi    r7, r0, 1;              /* Arg 3: int in_syscall */
-        bralid  r15, do_signal; /* Handle any signals */
-        add     r6, r0, r0;             /* Arg 2: sigset_t *oldset */
+        bralid  r15, do_notify_resume;  /* Handle any signals */
+        addi    r6, r0, 1;              /* Arg 2: int in_syscall */
 
 /* Finally, return to user state.  */
 1:      set_bip;                        /*  Ints masked for state restore */
@@ -622,7 +621,7 @@ C_ENTRY(ret_from_exc):
         /* Maybe handle a signal */
 5:      lwi     r11, CURRENT_TASK, TS_THREAD_INFO;      /* get thread info */
         lwi     r11, r11, TI_FLAGS;     /* get flags in thread info */
-        andi    r11, r11, _TIF_SIGPENDING;
+        andi    r11, r11, _TIF_SIGPENDING | _TIF_NOTIFY_RESUME;
         beqi    r11, 1f;                /* Signals to handle, handle them */
 
         /*
@@ -635,11 +634,10 @@ C_ENTRY(ret_from_exc):
          * traps), but signal handlers may want to examine or change the
          * complete register state.  Here we save anything not saved by
          * the normal entry sequence, so that it may be safely restored
-         * (in a possibly modified form) after do_signal returns. */
+         * (in a possibly modified form) after do_notify_resume returns. */
         addik   r5, r1, 0;              /* Arg 1: struct pt_regs *regs */
-        addi    r7, r0, 0;              /* Arg 3: int in_syscall */
-        bralid  r15, do_signal; /* Handle any signals */
-        add     r6, r0, r0;             /* Arg 2: sigset_t *oldset */
+        bralid  r15, do_notify_resume;  /* Handle any signals */
+        addi    r6, r0, 0;              /* Arg 2: int in_syscall */
 
 /* Finally, return to user state.  */
 1:      set_bip;                        /* Ints masked for state restore */
@@ -732,13 +730,12 @@ ret_from_irq:
     /* Maybe handle a signal */
 5:      lwi     r11, CURRENT_TASK, TS_THREAD_INFO; /* MS: get thread info */
         lwi     r11, r11, TI_FLAGS; /* get flags in thread info */
-        andi    r11, r11, _TIF_SIGPENDING;
+        andi    r11, r11, _TIF_SIGPENDING | _TIF_NOTIFY_RESUME;
         beqid   r11, no_intr_resched
 /* Handle a signal return; Pending signals should be in r18. */
-        addi    r7, r0, 0; /* Arg 3: int in_syscall */
         addik   r5, r1, 0; /* Arg 1: struct pt_regs *regs */
-        bralid  r15, do_signal; /* Handle any signals */
-        add     r6, r0, r0; /* Arg 2: sigset_t *oldset */
+        bralid  r15, do_notify_resume;  /* Handle any signals */
+        addi    r6, r0, 0; /* Arg 2: int in_syscall */
 
 /* Finally, return to user state. */
 no_intr_resched:
@@ -869,13 +866,12 @@ dbtrap_call: /* Return point for kernel/user entry + 8 because of rtsd r15, 8 */
         /* Maybe handle a signal */
 5:      lwi     r11, CURRENT_TASK, TS_THREAD_INFO;      /* get thread info */
         lwi     r11, r11, TI_FLAGS;     /* get flags in thread info */
-        andi    r11, r11, _TIF_SIGPENDING;
+        andi    r11, r11, _TIF_SIGPENDING | _TIF_NOTIFY_RESUME;
         beqi    r11, 1f;                /* Signals to handle, handle them */
 
         addik   r5, r1, 0;              /* Arg 1: struct pt_regs *regs */
-        addi  r7, r0, 0;        /* Arg 3: int in_syscall */
-        bralid  r15, do_signal; /* Handle any signals */
-        add     r6, r0, r0;             /* Arg 2: sigset_t *oldset */
+        bralid  r15, do_notify_resume;  /* Handle any signals */
+        addi  r6, r0, 0;        /* Arg 2: int in_syscall */
 
 /* Finally, return to user state.  */
 1:      swi     CURRENT_TASK, r0, PER_CPU(CURRENT_SAVE); /* save current */
diff --git a/arch/microblaze/kernel/signal.c b/arch/microblaze/kernel/signal.c
index 599671168980..7f4c7bef1642 100644
--- a/arch/microblaze/kernel/signal.c
+++ b/arch/microblaze/kernel/signal.c
@@ -31,6 +31,7 @@
 #include <linux/personality.h>
 #include <linux/percpu.h>
 #include <linux/linkage.h>
+#include <linux/tracehook.h>
 #include <asm/entry.h>
 #include <asm/ucontext.h>
 #include <linux/uaccess.h>
@@ -42,8 +43,6 @@
 
 #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
 
-asmlinkage int do_signal(struct pt_regs *regs, sigset_t *oldset, int in_sycall);
-
 asmlinkage long
 sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss,
                 struct pt_regs *regs)
@@ -98,6 +97,9 @@ asmlinkage long sys_rt_sigreturn(struct pt_regs *regs)
         sigset_t set;
         int rval;
 
+        /* Always make any pending restarted system calls return -EINTR */
+        current_thread_info()->restart_block.fn = do_no_restart_syscall;
+
         if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
                 goto badframe;
 
@@ -105,10 +107,7 @@ asmlinkage long sys_rt_sigreturn(struct pt_regs *regs)
                 goto badframe;
 
         sigdelsetmask(&set, ~_BLOCKABLE);
-        spin_lock_irq(&current->sighand->siglock);
-        current->blocked = set;
-        recalc_sigpending();
-        spin_unlock_irq(&current->sighand->siglock);
+        set_current_blocked(&set);
 
         if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &rval))
                 goto badframe;
@@ -169,7 +168,7 @@ get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size)
         return (void __user *)((sp - frame_size) & -8UL);
 }
 
-static void setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
+static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
                         sigset_t *set, struct pt_regs *regs)
 {
         struct rt_sigframe __user *frame;
@@ -267,12 +266,11 @@ static void setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
                 current->comm, current->pid, frame, regs->pc);
 #endif
 
-        return;
+        return 0;
 
 give_sigsegv:
-        if (sig == SIGSEGV)
-                ka->sa.sa_handler = SIG_DFL;
-        force_sig(SIGSEGV, current);
+        force_sigsegv(sig, current);
+        return -EFAULT;
 }
 
 /* Handle restarting system calls */
@@ -316,24 +314,20 @@ static int
 handle_signal(unsigned long sig, struct k_sigaction *ka,
                 siginfo_t *info, sigset_t *oldset, struct pt_regs *regs)
 {
+        int ret;
+
         /* Set up the stack frame */
         if (ka->sa.sa_flags & SA_SIGINFO)
-                setup_rt_frame(sig, ka, info, oldset, regs);
+                ret = setup_rt_frame(sig, ka, info, oldset, regs);
         else
-                setup_rt_frame(sig, ka, NULL, oldset, regs);
-
-        if (ka->sa.sa_flags & SA_ONESHOT)
-                ka->sa.sa_handler = SIG_DFL;
-
-        if (!(ka->sa.sa_flags & SA_NODEFER)) {
-                spin_lock_irq(&current->sighand->siglock);
-                sigorsets(&current->blocked,
-                                &current->blocked, &ka->sa.sa_mask);
-                sigaddset(&current->blocked, sig);
-                recalc_sigpending();
-                spin_unlock_irq(&current->sighand->siglock);
-        }
-        return 1;
+                ret = setup_rt_frame(sig, ka, NULL, oldset, regs);
+
+        if (ret)
+                return ret;
+
+        block_sigmask(ka, sig);
+
+        return 0;
 }
 
 /*
@@ -345,24 +339,17 @@ handle_signal(unsigned long sig, struct k_sigaction *ka,
  * 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, int in_syscall)
+static void do_signal(struct pt_regs *regs, int in_syscall)
 {
         siginfo_t info;
         int signr;
         struct k_sigaction ka;
+        sigset_t *oldset;
 #ifdef DEBUG_SIG
-        printk(KERN_INFO "do signal: %p %p %d\n", regs, oldset, in_syscall);
+        printk(KERN_INFO "do signal: %p %d\n", regs, in_syscall);
         printk(KERN_INFO "do signal2: %lx %lx %ld [%lx]\n", regs->pc, regs->r1,
                         regs->r12, current_thread_info()->flags);
 #endif
-        /*
-         * We want the common case to go fast, which
-         * is why we may in certain cases get here from
-         * kernel mode. Just return without doing anything
-         * if so.
-         */
-        if (kernel_mode(regs))
-                return 1;
 
         if (current_thread_info()->status & TS_RESTORE_SIGMASK)
                 oldset = &current->saved_sigmask;
@@ -374,7 +361,7 @@ int do_signal(struct pt_regs *regs, sigset_t *oldset, int in_syscall)
                 /* Whee! Actually deliver the signal. */
                 if (in_syscall)
                         handle_restart(regs, &ka, 1);
-                if (handle_signal(signr, &ka, &info, oldset, regs)) {
+                if (!handle_signal(signr, &ka, &info, oldset, regs)) {
                         /*
                          * A signal was successfully delivered; the saved
                          * sigmask will have been stored in the signal frame,
@@ -384,7 +371,7 @@ int do_signal(struct pt_regs *regs, sigset_t *oldset, int in_syscall)
                         current_thread_info()->status &=
                             ~TS_RESTORE_SIGMASK;
                 }
-                return 1;
+                return;
         }
 
         if (in_syscall)
@@ -398,7 +385,25 @@ int do_signal(struct pt_regs *regs, sigset_t *oldset, int in_syscall)
                 current_thread_info()->status &= ~TS_RESTORE_SIGMASK;
                 sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
         }
+}
 
-        /* Did we come from a system call? */
-        return 0;
+void do_notify_resume(struct pt_regs *regs, int in_syscall)
+{
+        /*
+         * We want the common case to go fast, which
+         * is why we may in certain cases get here from
+         * kernel mode. Just return without doing anything
+         * if so.
+         */
+        if (kernel_mode(regs))
+                return;
+
+        if (test_thread_flag(TIF_SIGPENDING))
+                do_signal(regs, in_syscall);
+
+        if (test_and_clear_thread_flag(TIF_NOTIFY_RESUME)) {
+                tracehook_notify_resume(regs);
+                if (current->replacement_session_keyring)
+                        key_replace_session_keyring();
+        }
 }