From: Luming Yu <luyu@redhat.com>
Date: Thu, 14 Feb 2008 16:22:21 +0800
Subject: [ia64] add TIF_RESTORE_SIGMASK and pselect/ppoll syscall
Message-id: 47B3FA3D.8080203@redhat.com
O-Subject: [RHEL 5.3 PATCH] bz206806: IA64 kernel lacks TIF_RESTORE_SIGMASK and hence pselect() and ppoll() system calls.
Bugzilla: 206806
RH-Acked-by: Kyle McMartin <kmcmartin@redhat.com>
RH-Acked-by: Prarit Bhargava <prarit@redhat.com>

bz206806

Description of problem:
IA64 kernel lacks TIF_RESTORE_SIGMASK and hence pselect() and ppoll()
system calls.

Upstream status:
It is upstream.

http://marc2.theaimsgroup.com/?l=linux-ia64&m=116956784030693&w=2 <http://marc2.theaimsgroup.com/?l=linux-ia64&m=116956784030693&w=2>

http://marc2.theaimsgroup.com/?l=linux-ia64&m=116956787304127&w=2 <http://marc2.theaimsgroup.com/?l=linux-ia64&m=116956787304127&w=2>

Git commit:
http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=4a177cbf84f827cf9f1d6cfa5264fafd3cc33ce0
http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=e180583b85f4a48bd55924712c88e5d8eb182e08

The attached back port of the patch is a refresh of back port patch at
https://bugzilla.redhat.com/show_bug.cgi?id=206806#c6 against
2.6.18-79.el5 kernel.

Test status:
The patch has passed my general test.
But the pselect01 test case in ltp makes no difference on kernels with
and without the patch.

Please review, test and ACK.

Thanks,
Luming

 arch/ia64/ia32/ia32_entry.S    |   39 +---------------------
 arch/ia64/ia32/ia32_signal.c   |   59 ++++++---------------------------
 arch/ia64/kernel/entry.S       |   30 +----------------
 arch/ia64/kernel/process.c     |    6 ++--
 arch/ia64/kernel/sigframe.h    |    2 +-
 arch/ia64/kernel/signal.c      |   71 +++++++++++++---------------------------
 include/asm-ia64/thread_info.h |    4 ++-
 include/asm-ia64/unistd.h      |    2 +
 8 files changed, 45 insertions(+), 168 deletions(-)

diff --git a/arch/ia64/ia32/ia32_entry.S b/arch/ia64/ia32/ia32_entry.S
index daaa061..17b090f 100644
--- a/arch/ia64/ia32/ia32_entry.S
+++ b/arch/ia64/ia32/ia32_entry.S
@@ -52,43 +52,6 @@ ENTRY(ia32_clone)
 	br.ret.sptk.many rp
 END(ia32_clone)
 
-ENTRY(sys32_rt_sigsuspend)
-	.prologue ASM_UNW_PRLG_RP|ASM_UNW_PRLG_PFS, ASM_UNW_PRLG_GRSAVE(8)
-	alloc loc1=ar.pfs,8,2,3,0		// preserve all eight input regs
-	mov loc0=rp
-	mov out0=in0				// mask
-	mov out1=in1				// sigsetsize
-	mov out2=sp				// out2 = &sigscratch
-	.fframe 16
-	adds sp=-16,sp				// allocate dummy "sigscratch"
-	;;
-	.body
-	br.call.sptk.many rp=ia32_rt_sigsuspend
-1:	.restore sp
-	adds sp=16,sp
-	mov rp=loc0
-	mov ar.pfs=loc1
-	br.ret.sptk.many rp
-END(sys32_rt_sigsuspend)
-
-ENTRY(sys32_sigsuspend)
-	.prologue ASM_UNW_PRLG_RP|ASM_UNW_PRLG_PFS, ASM_UNW_PRLG_GRSAVE(8)
-	alloc loc1=ar.pfs,8,2,3,0		// preserve all eight input regs
-	mov loc0=rp
-	mov out0=in2				// mask (first two args are ignored)
-	;;
-	mov out1=sp				// out1 = &sigscratch
-	.fframe 16
-	adds sp=-16,sp				// allocate dummy "sigscratch"
-	.body
-	br.call.sptk.many rp=ia32_sigsuspend
-1:	.restore sp
-	adds sp=16,sp
-	mov rp=loc0
-	mov ar.pfs=loc1
-	br.ret.sptk.many rp
-END(sys32_sigsuspend)
-
 GLOBAL_ENTRY(ia32_ret_from_clone)
 	PT_REGS_UNWIND_INFO(0)
 {	/*
@@ -389,7 +352,7 @@ ia32_syscall_table:
 	data8 sys_rt_sigpending
 	data8 compat_sys_rt_sigtimedwait
 	data8 sys32_rt_sigqueueinfo
-	data8 sys32_rt_sigsuspend
+	data8 compat_sys_rt_sigsuspend
 	data8 sys32_pread	  /* 180 */
 	data8 sys32_pwrite
 	data8 sys_chown	/* 16-bit version */
diff --git a/arch/ia64/ia32/ia32_signal.c b/arch/ia64/ia32/ia32_signal.c
index b3355a9..32e0b64 100644
--- a/arch/ia64/ia32/ia32_signal.c
+++ b/arch/ia64/ia32/ia32_signal.c
@@ -452,59 +452,20 @@ sigact_set_handler (struct k_sigaction *sa, unsigned int handler, unsigned int r
 		sa->sa.sa_handler = (__sighandler_t) (((unsigned long) restorer << 32) | handler);
 }
 
-long
-__ia32_rt_sigsuspend (compat_sigset_t *sset, unsigned int sigsetsize, struct sigscratch *scr)
+asmlinkage long
+sys32_sigsuspend (int history0, int history1, old_sigset_t mask)
 {
-	extern long ia64_do_signal (sigset_t *oldset, struct sigscratch *scr, long in_syscall);
-	sigset_t oldset, set;
-
-	scr->scratch_unat = 0;	/* avoid leaking kernel bits to user level */
-	memset(&set, 0, sizeof(set));
-
-	memcpy(&set.sig, &sset->sig, sigsetsize);
-
-	sigdelsetmask(&set, ~_BLOCKABLE);
-
+	mask &= _BLOCKABLE;
 	spin_lock_irq(&current->sighand->siglock);
-	{
-		oldset = current->blocked;
-		current->blocked = set;
-		recalc_sigpending();
-	}
+	current->saved_sigmask = current->blocked;
+	siginitset(&current->blocked, mask);
+	recalc_sigpending();
 	spin_unlock_irq(&current->sighand->siglock);
 
-	/*
-	 * The return below usually returns to the signal handler.  We need to pre-set the
-	 * correct error code here to ensure that the right values get saved in sigcontext
-	 * by ia64_do_signal.
-	 */
-	scr->pt.r8 = -EINTR;
-	while (1) {
-		current->state = TASK_INTERRUPTIBLE;
-		schedule();
-		if (ia64_do_signal(&oldset, scr, 1))
-			return -EINTR;
-	}
-}
-
-asmlinkage long
-ia32_rt_sigsuspend (compat_sigset_t __user *uset, unsigned int sigsetsize, struct sigscratch *scr)
-{
-	compat_sigset_t set;
-
-	if (sigsetsize > sizeof(compat_sigset_t))
-		return -EINVAL;
-
-	if (copy_from_user(&set.sig, &uset->sig, sigsetsize))
-		return -EFAULT;
-
-	return __ia32_rt_sigsuspend(&set, sigsetsize, scr);
-}
-
-asmlinkage long
-ia32_sigsuspend (unsigned int mask, struct sigscratch *scr)
-{
-	return __ia32_rt_sigsuspend((compat_sigset_t *) &mask, sizeof(mask), scr);
+	current->state = TASK_INTERRUPTIBLE;
+	schedule();
+	set_thread_flag(TIF_RESTORE_SIGMASK);
+	return -ERESTARTNOHAND;
 }
 
 asmlinkage long
diff --git a/arch/ia64/kernel/entry.S b/arch/ia64/kernel/entry.S
index b4b8a36..b3dc97f 100644
--- a/arch/ia64/kernel/entry.S
+++ b/arch/ia64/kernel/entry.S
@@ -1208,32 +1208,6 @@ GLOBAL_ENTRY(notify_resume_user)
 	br.ret.sptk.many rp
 END(notify_resume_user)
 
-GLOBAL_ENTRY(sys_rt_sigsuspend)
-	.prologue ASM_UNW_PRLG_RP|ASM_UNW_PRLG_PFS, ASM_UNW_PRLG_GRSAVE(8)
-	alloc loc1=ar.pfs,8,2,3,0 // preserve all eight input regs in case of syscall restart!
-	mov r9=ar.unat
-	mov loc0=rp				// save return address
-	mov out0=in0				// mask
-	mov out1=in1				// sigsetsize
-	adds out2=8,sp				// out2=&sigscratch->ar_pfs
-	;;
-	.fframe 16
-	.spillsp ar.unat, 16
-	st8 [sp]=r9,-16				// allocate space for ar.unat and save it
-	st8 [out2]=loc1,-8			// save ar.pfs, out2=&sigscratch
-	.body
-	br.call.sptk.many rp=ia64_rt_sigsuspend
-.ret17:	.restore sp
-	adds sp=16,sp				// pop scratch stack space
-	;;
-	ld8 r9=[sp]				// load new unat from sw->caller_unat
-	mov rp=loc0
-	;;
-	mov ar.unat=r9
-	mov ar.pfs=loc1
-	br.ret.sptk.many rp
-END(sys_rt_sigsuspend)
-
 ENTRY(sys_rt_sigreturn)
 	PT_REGS_UNWIND_INFO(0)
 	/*
@@ -1615,8 +1589,8 @@ sys_call_table:
 	data8 sys_readlinkat
 	data8 sys_fchmodat
 	data8 sys_faccessat
-	data8 sys_ni_syscall			// reserved for pselect
-	data8 sys_ni_syscall			// 1295 reserved for ppoll
+	data8 sys_pselect6
+	data8 sys_ppoll
 	data8 sys_unshare
 	data8 sys_splice
 	data8 sys_set_robust_list
diff --git a/arch/ia64/kernel/process.c b/arch/ia64/kernel/process.c
index 634b385..90ab0a8 100644
--- a/arch/ia64/kernel/process.c
+++ b/arch/ia64/kernel/process.c
@@ -157,7 +157,7 @@ show_regs (struct pt_regs *regs)
 }
 
 void
-do_notify_resume_user (sigset_t *oldset, struct sigscratch *scr, long in_syscall)
+do_notify_resume_user (sigset_t *unused, struct sigscratch *scr, long in_syscall)
 {
 	if (fsys_mode(current, &scr->pt)) {
 		/* defer signal-handling etc. until we return to privilege-level 0.  */
@@ -173,8 +173,8 @@ do_notify_resume_user (sigset_t *oldset, struct sigscratch *scr, long in_syscall
 #endif
 
 	/* deal with pending signal delivery */
-	if (test_thread_flag(TIF_SIGPENDING))
-		ia64_do_signal(oldset, scr, in_syscall);
+	if (test_thread_flag(TIF_SIGPENDING)||test_thread_flag(TIF_RESTORE_SIGMASK))
+		ia64_do_signal(scr, in_syscall);
 
 	/* copy user rbs to kernel rbs */
 	if (unlikely(test_thread_flag(TIF_RESTORE_RSE)))
diff --git a/arch/ia64/kernel/sigframe.h b/arch/ia64/kernel/sigframe.h
index 37b986c..9fd9a19 100644
--- a/arch/ia64/kernel/sigframe.h
+++ b/arch/ia64/kernel/sigframe.h
@@ -22,4 +22,4 @@ struct sigframe {
 	struct sigcontext sc;
 };
 
-extern long ia64_do_signal (sigset_t *, struct sigscratch *, long);
+extern void ia64_do_signal (struct sigscratch *, long);
diff --git a/arch/ia64/kernel/signal.c b/arch/ia64/kernel/signal.c
index fd0145d..467d763 100644
--- a/arch/ia64/kernel/signal.c
+++ b/arch/ia64/kernel/signal.c
@@ -41,47 +41,6 @@
 # define GET_SIGSET(k,u)	__get_user((k)->sig[0], &(u)->sig[0])
 #endif
 
-long
-ia64_rt_sigsuspend (sigset_t __user *uset, size_t sigsetsize, struct sigscratch *scr)
-{
-	sigset_t oldset, set;
-
-	/* XXX: Don't preclude handling different sized sigset_t's.  */
-	if (sigsetsize != sizeof(sigset_t))
-		return -EINVAL;
-
-	if (!access_ok(VERIFY_READ, uset, sigsetsize))
-		return -EFAULT;
-
-	if (GET_SIGSET(&set, uset))
-		return -EFAULT;
-
-	sigdelsetmask(&set, ~_BLOCKABLE);
-
-	spin_lock_irq(&current->sighand->siglock);
-	{
-		oldset = current->blocked;
-		current->blocked = set;
-		recalc_sigpending();
-	}
-	spin_unlock_irq(&current->sighand->siglock);
-
-	/*
-	 * The return below usually returns to the signal handler.  We need to
-	 * pre-set the correct error code here to ensure that the right values
-	 * get saved in sigcontext by ia64_do_signal.
-	 */
-	scr->pt.r8 = EINTR;
-	scr->pt.r10 = -1;
-
-	while (1) {
-		current->state = TASK_INTERRUPTIBLE;
-		schedule();
-		if (ia64_do_signal(&oldset, scr, 1))
-			return -EINTR;
-	}
-}
-
 asmlinkage long
 sys_sigaltstack (const stack_t __user *uss, stack_t __user *uoss, long arg2,
 		 long arg3, long arg4, long arg5, long arg6, long arg7,
@@ -480,10 +439,11 @@ handle_signal (unsigned long sig, struct k_sigaction *ka, siginfo_t *info, sigse
  * Note that `init' is a special process: it doesn't get signals it doesn't want to
  * handle.  Thus you cannot kill init even with a SIGKILL even by mistake.
  */
-long
-ia64_do_signal (sigset_t *oldset, struct sigscratch *scr, long in_syscall)
+void
+ia64_do_signal (struct sigscratch *scr, long in_syscall)
 {
 	struct k_sigaction ka;
+	sigset_t *oldset;
 	siginfo_t info;
 	long restart = in_syscall;
 	long errno = scr->pt.r8;
@@ -495,9 +455,11 @@ ia64_do_signal (sigset_t *oldset, struct sigscratch *scr, long in_syscall)
 	 * doing anything if so.
 	 */
 	if (!user_mode(&scr->pt))
-		return 0;
+		return;
 
-	if (!oldset)
+	if (test_thread_flag(TIF_RESTORE_SIGMASK))
+		oldset = &current->saved_sigmask;
+	else
 		oldset = &current->blocked;
 
 	/*
@@ -560,8 +522,15 @@ ia64_do_signal (sigset_t *oldset, struct sigscratch *scr, long in_syscall)
 		 * Whee!  Actually deliver the signal.  If the delivery failed, we need to
 		 * continue to iterate in this loop so we can deliver the SIGSEGV...
 		 */
-		if (handle_signal(signr, &ka, &info, oldset, scr))
-			return 1;
+		if (handle_signal(signr, &ka, &info, oldset, scr)) {
+			/* a signal was successfully delivered; the saved
+			 * sigmask will have been stored in the signal frame,
+			 * and will be restored by sigreturn, so we can simply
+			 * clear the TIF_RESTORE_SIGMASK flag */
+			if (test_thread_flag(TIF_RESTORE_SIGMASK))
+				clear_thread_flag(TIF_RESTORE_SIGMASK);
+			return;
+		}
 	}
 
 	/* Did we come from a system call? */
@@ -587,5 +556,11 @@ ia64_do_signal (sigset_t *oldset, struct sigscratch *scr, long in_syscall)
 			}
 		}
 	}
-	return 0;
+
+	/* if there's no signal to deliver, we just put the saved sigmask
+	 * back */
+	if (test_thread_flag(TIF_RESTORE_SIGMASK)) {
+		clear_thread_flag(TIF_RESTORE_SIGMASK);
+		sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
+	}
 }
diff --git a/include/asm-ia64/thread_info.h b/include/asm-ia64/thread_info.h
index ebca7a1..0b5ff6b 100644
--- a/include/asm-ia64/thread_info.h
+++ b/include/asm-ia64/thread_info.h
@@ -85,6 +85,7 @@ struct thread_info {
 #define TIF_SYSCALL_TRACE	3	/* syscall trace active */
 #define TIF_SYSCALL_AUDIT	4	/* syscall auditing active */
 #define TIF_SINGLESTEP		5	/* restore singlestep on return to user mode */
+#define TIF_RESTORE_SIGMASK	6	/* restore signal mask in do_signal() */
 #define TIF_POLLING_NRFLAG	16	/* true if poll_idle() is polling TIF_NEED_RESCHED */
 #define TIF_MEMDIE		17
 #define TIF_MCA_INIT		18	/* this task is processing MCA or INIT */
@@ -96,6 +97,7 @@ struct thread_info {
 #define _TIF_SINGLESTEP		(1 << TIF_SINGLESTEP)
 #define _TIF_SYSCALL_TRACEAUDIT	(_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT|_TIF_SINGLESTEP)
 #define _TIF_NOTIFY_RESUME	(1 << TIF_NOTIFY_RESUME)
+#define _TIF_RESTORE_SIGMASK	(1 << TIF_RESTORE_SIGMASK)
 #define _TIF_SIGPENDING		(1 << TIF_SIGPENDING)
 #define _TIF_NEED_RESCHED	(1 << TIF_NEED_RESCHED)
 #define _TIF_POLLING_NRFLAG	(1 << TIF_POLLING_NRFLAG)
@@ -104,7 +106,7 @@ struct thread_info {
 #define _TIF_RESTORE_RSE	(1 << TIF_RESTORE_RSE)
 
 /* "work to do on user-return" bits */
-#define TIF_ALLWORK_MASK	(_TIF_NOTIFY_RESUME|_TIF_SIGPENDING|_TIF_NEED_RESCHED|_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT)
+#define TIF_ALLWORK_MASK	(_TIF_NOTIFY_RESUME|_TIF_SIGPENDING|_TIF_NEED_RESCHED|_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT|_TIF_RESTORE_SIGMASK)
 /* like TIF_ALLWORK_BITS but sans TIF_SYSCALL_TRACE or TIF_SYSCALL_AUDIT */
 #define TIF_WORK_MASK		(TIF_ALLWORK_MASK&~(_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT))
 
diff --git a/include/asm-ia64/unistd.h b/include/asm-ia64/unistd.h
index ae47f56..e925cf6 100644
--- a/include/asm-ia64/unistd.h
+++ b/include/asm-ia64/unistd.h
@@ -300,6 +300,7 @@
 #define NR_syscalls			281 /* length of syscall table */
 
 #define __ARCH_WANT_SYS_RT_SIGACTION
+#define __ARCH_WANT_SYS_RT_SIGSUSPEND
 
 #ifdef CONFIG_IA32_SUPPORT
 # define __ARCH_WANT_SYS_FADVISE64
@@ -310,6 +311,7 @@
 # define __ARCH_WANT_SYS_OLDUMOUNT
 # define __ARCH_WANT_SYS_SIGPENDING
 # define __ARCH_WANT_SYS_SIGPROCMASK
+# define __ARCH_WANT_COMPAT_SYS_RT_SIGSUSPEND
 # define __ARCH_WANT_COMPAT_SYS_TIME
 #endif