[XTENSA] Remove non-rt signal handling

The non-rt signal handling was never really used, so we don't break
anything. This patch also cleans up the signal stack-frame to make
it independent from the processor configuration. It also improves
the method used for controlling single-stepping. We now save and
restore the 'icountlevel' register that controls single stepping
and set or clear the saved state to enable or disable it.

Signed-off-by: Chris Zankel <chris@zankel.net>

3 files changed, 334 insertions, 498 deletions

diff --git a/arch/xtensa/kernel/asm-offsets.c b/arch/xtensa/kernel/asm-offsets.c
index 698079b..d0323cd 100644
--- a/arch/xtensa/kernel/asm-offsets.c
+++ b/arch/xtensa/kernel/asm-offsets.c
@@ -39,6 +39,7 @@ int main(void)
 	DEFINE(PT_LEND, offsetof (struct pt_regs, lend));
 	DEFINE(PT_LCOUNT, offsetof (struct pt_regs, lcount));
 	DEFINE(PT_SAR, offsetof (struct pt_regs, sar));
+	DEFINE(PT_ICOUNTLEVEL, offsetof (struct pt_regs, icountlevel));
 	DEFINE(PT_SYSCALL, offsetof (struct pt_regs, syscall));
 	DEFINE(PT_AREG, offsetof (struct pt_regs, areg[0]));
 	DEFINE(PT_AREG0, offsetof (struct pt_regs, areg[0]));
diff --git a/arch/xtensa/kernel/entry.S b/arch/xtensa/kernel/entry.S
index 9e271ba..8dc7a2c 100644
--- a/arch/xtensa/kernel/entry.S
+++ b/arch/xtensa/kernel/entry.S
@@ -125,8 +125,9 @@ _user_exception:
 
 	movi	a2, 0
 	rsr	a3, SAR
-	wsr	a2, ICOUNTLEVEL
+	xsr	a2, ICOUNTLEVEL
 	s32i	a3, a1, PT_SAR
+	s32i	a2, a1, PT_ICOUNTLEVEL
 
 	/* Rotate ws so that the current windowbase is at bit0. */
 	/* Assume ws = xxwww1yyyy. Rotate ws right, so that a2 = yyyyxxwww1 */
@@ -276,8 +277,9 @@ _kernel_exception:
 
 	movi	a2, 0
 	rsr	a3, SAR
-	wsr	a2, ICOUNTLEVEL
+	xsr	a2, ICOUNTLEVEL
 	s32i	a3, a1, PT_SAR
+	s32i	a2, a1, PT_ICOUNTLEVEL
 
 	/* Rotate ws so that the current windowbase is at bit0. */
 	/* Assume ws = xxwww1yyyy. Rotate ws right, so that a2 = yyyyxxwww1 */
@@ -330,14 +332,16 @@ _kernel_exception:
 
 common_exception:
 
-	/* Save EXCVADDR, DEBUGCAUSE, and PC, and clear LCOUNT */
+	/* Save some registers, disable loops and clear the syscall flag. */
 
 	rsr	a2, DEBUGCAUSE
 	rsr	a3, EPC_1
 	s32i	a2, a1, PT_DEBUGCAUSE
 	s32i	a3, a1, PT_PC
 
+	movi	a2, -1
 	rsr	a3, EXCVADDR
+	s32i	a2, a1, PT_SYSCALL
 	movi	a2, 0
 	s32i	a3, a1, PT_EXCVADDR
 	xsr	a2, LCOUNT
@@ -450,27 +454,8 @@ common_exception_return:
 
 	/* Restore the state of the task and return from the exception. */
 
-
-	/* If we are returning from a user exception, and the process
-	 * to run next has PT_SINGLESTEP set, we want to setup
-	 * ICOUNT and ICOUNTLEVEL to step one instruction.
-	 * PT_SINGLESTEP is set by sys_ptrace (ptrace.c)
-	 */
-
 4:	/* a2 holds GET_CURRENT(a2,a1)  */
 
-	l32i	a3, a2, TI_TASK
-	l32i	a3, a3, TASK_PTRACE
-	bbci.l	a3, PT_SINGLESTEP_BIT, 1f # jump if single-step flag is not set
-
-	movi	a3, -2			# PT_SINGLESTEP flag is set,
-	movi	a4, 1			# icountlevel of 1 means it won't
-	wsr	a3, ICOUNT		# start counting until after rfe
-	wsr	a4, ICOUNTLEVEL		# so setup icount & icountlevel.
-	isync
-
-1:
-
 #if XCHAL_EXTRA_SA_SIZE
 
 	/* For user exceptions, restore the extra state from the user's TCB. */
@@ -665,6 +650,13 @@ common_exception_exit:
 	wsr	a3, LEND
 	wsr	a2, LCOUNT
 
+	/* We control single stepping through the ICOUNTLEVEL register. */
+
+	l32i	a2, a1, PT_ICOUNTLEVEL
+	movi	a3, -2
+	wsr	a2, ICOUNTLEVEL
+	wsr	a3, ICOUNT
+
 	/* Check if it was double exception. */
 
 	l32i	a0, a1, PT_DEPC
diff --git a/arch/xtensa/kernel/signal.c b/arch/xtensa/kernel/signal.c
index 5810767..033aae0 100644
--- a/arch/xtensa/kernel/signal.c
+++ b/arch/xtensa/kernel/signal.c
@@ -1,397 +1,239 @@
-// TODO coprocessor stuff
 /*
- *  linux/arch/xtensa/kernel/signal.c
+ * arch/xtensa/kernel/signal.c
  *
- *  Copyright (C) 1991, 1992  Linus Torvalds
- *  1997-11-28  Modified for POSIX.1b signals by Richard Henderson
- *
- *  Joe Taylor <joe@tensilica.com>
- *  Chris Zankel <chris@zankel.net>
+ * Default platform functions.
  *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
  *
+ * Copyright (C) 2005, 2006 Tensilica Inc.
+ * Copyright (C) 1991, 1992  Linus Torvalds
+ * 1997-11-28  Modified for POSIX.1b signals by Richard Henderson
  *
+ * Chris Zankel <chris@zankel.net>
+ * Joe Taylor <joe@tensilica.com>
  */
 
-#include <asm/variant/core.h>
-#include <asm/coprocessor.h>
-#include <linux/sched.h>
-#include <linux/mm.h>
-#include <linux/smp.h>
-#include <linux/kernel.h>
 #include <linux/signal.h>
 #include <linux/errno.h>
-#include <linux/wait.h>
 #include <linux/ptrace.h>
-#include <linux/unistd.h>
-#include <linux/stddef.h>
 #include <linux/personality.h>
+#include <linux/freezer.h>
+
 #include <asm/ucontext.h>
 #include <asm/uaccess.h>
-#include <asm/pgtable.h>
 #include <asm/cacheflush.h>
+#include <asm/coprocessor.h>
+#include <asm/unistd.h>
 
 #define DEBUG_SIG  0
 
 #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
 
-asmlinkage long sys_wait4(pid_t pid,unsigned int * stat_addr, int options,
-			  struct rusage * ru);
 asmlinkage int do_signal(struct pt_regs *regs, sigset_t *oldset);
 
 extern struct task_struct *coproc_owners[];
 
+extern void release_all_cp (struct task_struct *);
 
-/*
- * Atomically swap in the new signal mask, and wait for a signal.
+struct rt_sigframe
+{
+	struct siginfo info;
+	struct ucontext uc;
+	cp_state_t cpstate;
+	unsigned char retcode[6];
+	unsigned int window[4];
+};
+
+/* 
+ * Flush register windows stored in pt_regs to stack.
+ * Returns 1 for errors.
+ *
+ * Note that windowbase, windowstart, and wmask are not updated!
  */
 
-int xtensa_sigsuspend(struct pt_regs *regs)
+int
+flush_window_regs_user(struct pt_regs *regs)
 {
-	old_sigset_t mask = (old_sigset_t) regs->areg[3];
-	sigset_t saveset;
+	const unsigned long ws = regs->windowstart;
+	const unsigned long wb = regs->windowbase;
+	unsigned long sp = 0;
+	unsigned long wm;
+	int err = 1;
+	int base;
 
-	mask &= _BLOCKABLE;
-	spin_lock_irq(&current->sighand->siglock);
-	saveset = current->blocked;
-	siginitset(&current->blocked, mask);
-	recalc_sigpending();
-	spin_unlock_irq(&current->sighand->siglock);
+	/* Return if no other frames. */
 
-	regs->areg[2] = -EINTR;
-	while (1) {
-		current->state = TASK_INTERRUPTIBLE;
-		schedule();
-		if (do_signal(regs, &saveset))
-			return -EINTR;
-	}
-}
+	if (regs->wmask == 1)
+		return 0;
 
-asmlinkage int
-xtensa_rt_sigsuspend(struct pt_regs *regs)
-{
-	sigset_t *unewset = (sigset_t *) regs->areg[4];
-	size_t sigsetsize = (size_t) regs->areg[3];
-	sigset_t saveset, newset;
-	/* XXX: Don't preclude handling different sized sigset_t's.  */
-	if (sigsetsize != sizeof(sigset_t))
-		return -EINVAL;
+	/* Rotate windowmask and skip empty frames. */
 
-	if (copy_from_user(&newset, unewset, sizeof(newset)))
-		return -EFAULT;
-	sigdelsetmask(&newset, ~_BLOCKABLE);
-	spin_lock_irq(&current->sighand->siglock);
-	saveset = current->blocked;
-	current->blocked = newset;
-	recalc_sigpending();
-	spin_unlock_irq(&current->sighand->siglock);
+	wm = (ws >> wb) | (ws << (XCHAL_NUM_AREGS / 4 - wb));
+	base = (XCHAL_NUM_AREGS / 4) - (regs->wmask >> 4);
+		
+	/* For call8 or call12 frames, we need the previous stack pointer. */
 
-	regs->areg[2] = -EINTR;
-	while (1) {
-		current->state = TASK_INTERRUPTIBLE;
-		schedule();
-		if (do_signal(regs, &saveset))
-			return -EINTR;
-	}
-}
+	if ((regs->wmask & 2) == 0)
+		if (__get_user(sp, (int*)(regs->areg[base * 4 + 1] - 12)))
+			goto errout;
 
-asmlinkage int
-xtensa_sigaction(int sig, const struct old_sigaction *act,
-	      struct old_sigaction *oact)
-{
-	struct k_sigaction new_ka, old_ka;
-	int ret;
+	/* Spill frames to stack. */
 
-	if (act) {
-		old_sigset_t mask;
-		if (!access_ok(VERIFY_READ, act, sizeof(*act)) ||
-		    __get_user(new_ka.sa.sa_handler, &act->sa_handler) ||
-		    __get_user(new_ka.sa.sa_restorer, &act->sa_restorer))
-			return -EFAULT;
-		__get_user(new_ka.sa.sa_flags, &act->sa_flags);
-		__get_user(mask, &act->sa_mask);
-		siginitset(&new_ka.sa.sa_mask, mask);
-	}
+	while (base < XCHAL_NUM_AREGS / 4) {
 
-	ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
+		int m = (wm >> base);
+		int inc = 0;
 
-	if (!ret && oact) {
-		if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) ||
-		    __put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||
-		    __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer))
-			return -EFAULT;
-		__put_user(old_ka.sa.sa_flags, &oact->sa_flags);
-		__put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask);
-	}
+		/* Save registers a4..a7 (call8) or a4...a11 (call12) */
 
-	return ret;
-}
+		if (m & 2) {			/* call4 */
+			inc = 1;
 
-asmlinkage int
-xtensa_sigaltstack(struct pt_regs *regs)
-{
-	const stack_t *uss = (stack_t *) regs->areg[4];
-	stack_t *uoss = (stack_t *) regs->areg[3];
+		} else if (m & 4) {		/* call8 */
+			if (copy_to_user((void*)(sp - 32),
+					   &regs->areg[(base + 1) * 4], 16))
+				goto errout;
+			inc = 2;
 
-	if (regs->depc > 64)
-		panic ("Double exception sys_sigreturn\n");
+		} else if (m & 8) {	/* call12 */
+			if (copy_to_user((void*)(sp - 48),
+					   &regs->areg[(base + 1) * 4], 32))
+				goto errout;
+			inc = 3;
+		}
 
+		/* Save current frame a0..a3 under next SP */
 
-	return do_sigaltstack(uss, uoss, regs->areg[1]);
-}
+		sp = regs->areg[((base + inc) * 4 + 1) % XCHAL_NUM_AREGS];
+		if (copy_to_user((void*)(sp - 16), &regs->areg[base * 4], 16))
+			goto errout;
+
+		/* Get current stack pointer for next loop iteration. */
+
+		sp = regs->areg[base * 4 + 1];
+		base += inc;
+	}
+
+	return 0;
 
+errout:
+	return err;
+}
 
 /*
- * Do a signal return; undo the signal stack.
+ * Note: We don't copy double exception 'regs', we have to finish double exc. 
+ * first before we return to signal handler! This dbl.exc.handler might cause 
+ * another double exception, but I think we are fine as the situation is the 
+ * same as if we had returned to the signal handerl and got an interrupt 
+ * immediately...
  */
 
-struct sigframe
-{
-	struct sigcontext sc;
-	struct _cpstate cpstate;
-	unsigned long extramask[_NSIG_WORDS-1];
-	unsigned char retcode[6];
-	unsigned int reserved[4]; /* Reserved area for chaining */
-	unsigned int window[4]; /* Window of 4 registers for initial context */
-};
-
-struct rt_sigframe
+static int
+setup_sigcontext(struct sigcontext __user *sc, cp_state_t *cpstate,
+		 struct pt_regs *regs, unsigned long mask)
 {
-	struct siginfo info;
-	struct ucontext uc;
-	struct _cpstate cpstate;
-	unsigned char retcode[6];
-	unsigned int reserved[4]; /* Reserved area for chaining */
-	unsigned int window[4]; /* Window of 4 registers for initial context */
-};
+	int err = 0;
 
-extern void release_all_cp (struct task_struct *);
+#define COPY(x)	err |= __put_user(regs->x, &sc->sc_##x)
+	COPY(pc);
+	COPY(ps);
+	COPY(lbeg);
+	COPY(lend);
+	COPY(lcount);
+	COPY(sar);
+#undef COPY
 
+	err |= flush_window_regs_user(regs);
+	err |= __copy_to_user (sc->sc_a, regs->areg, 16 * 4);
 
-// FIXME restore_cpextra
-static inline int
-restore_cpextra (struct _cpstate *buf)
-{
-#if 0
-	/* The signal handler may have used coprocessors in which
-	 * case they are still enabled.  We disable them to force a
-	 * reloading of the original task's CP state by the lazy
-	 * context-switching mechanisms of CP exception handling.
-	 * Also, we essentially discard any coprocessor state that the
-	 * signal handler created. */
+	// err |= __copy_to_user (sc->sc_a, regs->areg, XCHAL_NUM_AREGS * 4)
 
-	struct task_struct *tsk = current;
-	release_all_cp(tsk);
-	return __copy_from_user(tsk->thread.cpextra, buf, XTENSA_CP_EXTRA_SIZE);
+#if XCHAL_HAVE_CP
+# error Coprocessors unsupported
+	err |= save_cpextra(cpstate);
+	err |= __put_user(err ? NULL : cpstate, &sc->sc_cpstate);
 #endif
-	return 0;
-}
-
-/* Note: We don't copy double exception 'tregs', we have to finish double exc. first before we return to signal handler! This dbl.exc.handler might cause another double exception, but I think we are fine as the situation is the same as if we had returned to the signal handerl and got an interrupt immediately...
- */
+	/* non-iBCS2 extensions.. */
+	err |= __put_user(mask, &sc->oldmask);
 
+	return err;
+}
 
 static int
-restore_sigcontext(struct pt_regs *regs, struct sigcontext *sc)
+restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc)
 {
-	struct thread_struct *thread;
 	unsigned int err = 0;
 	unsigned long ps;
-	struct _cpstate *buf;
 
 #define COPY(x)	err |= __get_user(regs->x, &sc->sc_##x)
 	COPY(pc);
-	COPY(depc);
-	COPY(wmask);
 	COPY(lbeg);
 	COPY(lend);
 	COPY(lcount);
 	COPY(sar);
-	COPY(windowbase);
-	COPY(windowstart);
 #undef COPY
 
+	/* All registers were flushed to stack. Start with a prestine frame. */
+
+	regs->wmask = 1;
+	regs->windowbase = 0;
+	regs->windowstart = 1;
+
 	/* For PS, restore only PS.CALLINC.
 	 * Assume that all other bits are either the same as for the signal
 	 * handler, or the user mode value doesn't matter (e.g. PS.OWB).
 	 */
 	err |= __get_user(ps, &sc->sc_ps);
-	regs->ps = (regs->ps & ~PS_CALLINC_MASK)
-		| (ps & PS_CALLINC_MASK);
+	regs->ps = (regs->ps & ~PS_CALLINC_MASK) | (ps & PS_CALLINC_MASK);
 
 	/* Additional corruption checks */
 
-	if ((regs->windowbase >= (XCHAL_NUM_AREGS/4))
-	|| ((regs->windowstart & ~((1<<(XCHAL_NUM_AREGS/4)) - 1)) != 0) )
-		err = 1;
 	if ((regs->lcount > 0)
-	&& ((regs->lbeg > TASK_SIZE) || (regs->lend > TASK_SIZE)) )
+	    && ((regs->lbeg > TASK_SIZE) || (regs->lend > TASK_SIZE)) )
 		err = 1;
 
-	/* Restore extended register state.
-	 * See struct thread_struct in processor.h.
-	 */
-	thread = &current->thread;
-
-	err |= __copy_from_user (regs->areg, sc->sc_areg, XCHAL_NUM_AREGS*4);
-	err |= __get_user(buf, &sc->sc_cpstate);
-	if (buf) {
-		if (!access_ok(VERIFY_READ, buf, sizeof(*buf)))
-			goto badframe;
-		err |= restore_cpextra(buf);
-	}
-
-	regs->syscall = -1;		/* disable syscall checks */
-	return err;
-
-badframe:
-	return 1;
-}
-
-static inline void
-flush_my_cpstate(struct task_struct *tsk)
-{
-	unsigned long flags;
-	local_irq_save(flags);
-
-#if 0	// FIXME
-	for (i = 0; i < XCHAL_CP_NUM; i++) {
-		if (tsk == coproc_owners[i]) {
-			xthal_validate_cp(i);
-			xthal_save_cpregs(tsk->thread.cpregs_ptr[i], i);
+	err |= __copy_from_user(regs->areg, sc->sc_a, 16 * 4);
 
-			/* Invalidate and "disown" the cp to allow
-			 * callers the chance to reset cp state in the
-			 * task_struct. */
+#if XCHAL_HAVE_CP
+# error Coprocessors unsupported
+ 	/* The signal handler may have used coprocessors in which
+	 * case they are still enabled.  We disable them to force a
+	 * reloading of the original task's CP state by the lazy
+	 * context-switching mechanisms of CP exception handling.
+	 * Also, we essentially discard any coprocessor state that the
+	 * signal handler created. */
 
-			xthal_invalidate_cp(i);
-			coproc_owners[i] = 0;
-		}
+	if (!err) {
+	  struct task_struct *tsk = current;
+	  release_all_cp(tsk);
+	  err |= __copy_from_user(tsk->thread.cpextra, sc->sc_cpstate, 
+	      			  XTENSA_CP_EXTRA_SIZE);
 	}
 #endif
-	local_irq_restore(flags);
-}
-
-/* Return codes:
-	0:  nothing saved
-	1:  stuff to save, successful
-       -1:  stuff to save, error happened
-*/
-static int
-save_cpextra (struct _cpstate *buf)
-{
-#if XCHAL_CP_NUM == 0
-	return 0;
-#else
-
-	/* FIXME: If a task has never used a coprocessor, there is
-	 * no need to save and restore anything.  Tracking this
-	 * information would allow us to optimize this section.
-	 * Perhaps we can use current->used_math or (current->flags &
-	 * PF_USEDFPU) or define a new field in the thread
-	 * structure. */
-
-	/* We flush any live, task-owned cp state to the task_struct,
-	 * then copy it all to the sigframe.  Then we clear all
-	 * cp/extra state in the task_struct, effectively
-	 * clearing/resetting all cp/extra state for the signal
-	 * handler (cp-exception handling will load these new values
-	 * into the cp/extra registers.)  This step is important for
-	 * things like a floating-point cp, where the OS must reset
-	 * the FCR to the default rounding mode. */
-
-	int err = 0;
-	struct task_struct *tsk = current;
-
-	flush_my_cpstate(tsk);
-	/* Note that we just copy everything: 'extra' and 'cp' state together.*/
-	err |= __copy_to_user(buf, tsk->thread.cp_save, XTENSA_CP_EXTRA_SIZE);
-	memset(tsk->thread.cp_save, 0, XTENSA_CP_EXTRA_SIZE);
-
-#if (XTENSA_CP_EXTRA_SIZE == 0)
-#error Sanity check on memset above, cpextra_size should not be zero.
-#endif
-
-	return err ? -1 : 1;
-#endif
-}
-
-static int
-setup_sigcontext(struct sigcontext *sc, struct _cpstate *cpstate,
-		 struct pt_regs *regs, unsigned long mask)
-{
-	struct thread_struct *thread;
-	int err = 0;
-
-//printk("setup_sigcontext\n");
-#define COPY(x)	err |= __put_user(regs->x, &sc->sc_##x)
-	COPY(pc);
-	COPY(ps);
-	COPY(depc);
-	COPY(wmask);
-	COPY(lbeg);
-	COPY(lend);
-	COPY(lcount);
-	COPY(sar);
-	COPY(windowbase);
-	COPY(windowstart);
-#undef COPY
-
-	/* Save extended register state.
-	 * See struct thread_struct in processor.h.
-	 */
-	thread = &current->thread;
-	err |= __copy_to_user (sc->sc_areg, regs->areg, XCHAL_NUM_AREGS * 4);
-	err |= save_cpextra(cpstate);
-	err |= __put_user(err ? NULL : cpstate, &sc->sc_cpstate);
-	/* non-iBCS2 extensions.. */
-	err |= __put_user(mask, &sc->oldmask);
 
+	regs->syscall = -1;		/* disable syscall checks */
 	return err;
 }
 
-asmlinkage int xtensa_sigreturn(struct pt_regs *regs)
-{
-	struct sigframe *frame = (struct sigframe *)regs->areg[1];
-	sigset_t set;
-	if (regs->depc > 64)
-		panic ("Double exception sys_sigreturn\n");
-
-	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
-		goto badframe;
-
-	if (__get_user(set.sig[0], &frame->sc.oldmask)
-	    || (_NSIG_WORDS > 1
-		&& __copy_from_user(&set.sig[1], &frame->extramask,
-				    sizeof(frame->extramask))))
-		goto badframe;
-
-	sigdelsetmask(&set, ~_BLOCKABLE);
-
-	spin_lock_irq(&current->sighand->siglock);
-	current->blocked = set;
-	recalc_sigpending();
-	spin_unlock_irq(&current->sighand->siglock);
 
-	if (restore_sigcontext(regs, &frame->sc))
-		goto badframe;
-	return regs->areg[2];
 
-badframe:
-	force_sig(SIGSEGV, current);
-	return 0;
-}
+/*
+ * Do a signal return; undo the signal stack.
+ */
 
-asmlinkage int xtensa_rt_sigreturn(struct pt_regs *regs)
+asmlinkage long xtensa_rt_sigreturn(long a0, long a1, long a2, long a3,
+				    long a4, long a5, struct pt_regs *regs)
 {
-	struct rt_sigframe *frame = (struct rt_sigframe *)regs->areg[1];
+	struct rt_sigframe __user *frame;
 	sigset_t set;
-	stack_t st;
 	int ret;
+
 	if (regs->depc > 64)
-	{
-		printk("!!!!!!! DEPC !!!!!!!\n");
-		return 0;
-	}
+		panic("rt_sigreturn in double exception!\n");
+
+	frame = (struct rt_sigframe __user *) regs->areg[1];
 
 	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
 		goto badframe;
@@ -407,13 +249,11 @@ asmlinkage int xtensa_rt_sigreturn(struct pt_regs *regs)
 
 	if (restore_sigcontext(regs, &frame->uc.uc_mcontext))
 		goto badframe;
+
 	ret = regs->areg[2];
 
-	if (__copy_from_user(&st, &frame->uc.uc_stack, sizeof(st)))
+	if (do_sigaltstack(&frame->uc.uc_stack, NULL, regs->areg[1]) == -EFAULT)
 		goto badframe;
-	/* It is more difficult to avoid calling this function than to
-	   call it and ignore errors.  */
-	do_sigaltstack(&st, NULL, regs->areg[1]);
 
 	return ret;
 
@@ -422,77 +262,50 @@ badframe:
 	return 0;
 }
 
-/*
- * Set up a signal frame.
- */
+
 
 /*
- * Determine which stack to use..
+ * Set up a signal frame.
  */
-static inline void *
-get_sigframe(struct k_sigaction *ka, unsigned long sp, size_t frame_size)
-{
-	if ((ka->sa.sa_flags & SA_ONSTACK) != 0 && ! sas_ss_flags(sp))
-		sp = current->sas_ss_sp + current->sas_ss_size;
-
-	return (void *)((sp - frame_size) & -16ul);
-}
-
-#define USE_SIGRETURN		0
-#define USE_RT_SIGRETURN	1
 
 static int
-gen_return_code(unsigned char *codemem, unsigned int use_rt_sigreturn)
+gen_return_code(unsigned char *codemem)
 {
-	unsigned int retcall;
 	int err = 0;
 
-#if 0
-	/* Ignoring SA_RESTORER for now; it's supposed to be obsolete,
-	 * and the xtensa glibc doesn't use it.
+	/*
+	 * The 12-bit immediate is really split up within the 24-bit MOVI
+	 * instruction.  As long as the above system call numbers fit within
+	 * 8-bits, the following code works fine. See the Xtensa ISA for
+	 * details.
 	 */
-	if (ka->sa.sa_flags & SA_RESTORER) {
-		regs->pr = (unsigned long) ka->sa.sa_restorer;
-	} else
-#endif /* 0 */
-	{
-
-#if (__NR_sigreturn > 255) || (__NR_rt_sigreturn > 255)
-
-/* The 12-bit immediate is really split up within the 24-bit MOVI
- * instruction.  As long as the above system call numbers fit within
- * 8-bits, the following code works fine. See the Xtensa ISA for
- * details.
- */
 
-#error Generating the MOVI instruction below breaks!
+#if __NR_rt_sigreturn > 255
+# error Generating the MOVI instruction below breaks!
 #endif
 
-		retcall = use_rt_sigreturn ? __NR_rt_sigreturn : __NR_sigreturn;
-
 #ifdef __XTENSA_EB__   /* Big Endian version */
-		/* Generate instruction:  MOVI a2, retcall */
-		err |= __put_user(0x22, &codemem[0]);
-		err |= __put_user(0x0a, &codemem[1]);
-		err |= __put_user(retcall, &codemem[2]);
-		/* Generate instruction:  SYSCALL */
-		err |= __put_user(0x00, &codemem[3]);
-		err |= __put_user(0x05, &codemem[4]);
-		err |= __put_user(0x00, &codemem[5]);
+	/* Generate instruction:  MOVI a2, __NR_rt_sigreturn */
+	err |= __put_user(0x22, &codemem[0]);
+	err |= __put_user(0x0a, &codemem[1]);
+	err |= __put_user(__NR_rt_sigreturn, &codemem[2]);
+	/* Generate instruction:  SYSCALL */
+	err |= __put_user(0x00, &codemem[3]);
+	err |= __put_user(0x05, &codemem[4]);
+	err |= __put_user(0x00, &codemem[5]);
 
 #elif defined __XTENSA_EL__   /* Little Endian version */
-		/* Generate instruction:  MOVI a2, retcall */
-		err |= __put_user(0x22, &codemem[0]);
-		err |= __put_user(0xa0, &codemem[1]);
-		err |= __put_user(retcall, &codemem[2]);
-		/* Generate instruction:  SYSCALL */
-		err |= __put_user(0x00, &codemem[3]);
-		err |= __put_user(0x50, &codemem[4]);
-		err |= __put_user(0x00, &codemem[5]);
+	/* Generate instruction:  MOVI a2, __NR_rt_sigreturn */
+	err |= __put_user(0x22, &codemem[0]);
+	err |= __put_user(0xa0, &codemem[1]);
+	err |= __put_user(__NR_rt_sigreturn, &codemem[2]);
+	/* Generate instruction:  SYSCALL */
+	err |= __put_user(0x00, &codemem[3]);
+	err |= __put_user(0x50, &codemem[4]);
+	err |= __put_user(0x00, &codemem[5]);
 #else
-#error Must use compiler for Xtensa processors.
+# error Must use compiler for Xtensa processors.
 #endif
-	}
 
 	/* Flush generated code out of the data cache */
 
@@ -504,97 +317,29 @@ gen_return_code(unsigned char *codemem, unsigned int use_rt_sigreturn)
 	return err;
 }
 
-static void
-set_thread_state(struct pt_regs *regs, void *stack, unsigned char *retaddr,
-	void *handler, unsigned long arg1, void *arg2, void *arg3)
-{
-	/* Set up registers for signal handler */
-	start_thread(regs, (unsigned long) handler, (unsigned long) stack);
-
-	/* Set up a stack frame for a call4
-	 * Note: PS.CALLINC is set to one by start_thread
-	 */
-	regs->areg[4] = (((unsigned long) retaddr) & 0x3fffffff) | 0x40000000;
-	regs->areg[6] = arg1;
-	regs->areg[7] = (unsigned long) arg2;
-	regs->areg[8] = (unsigned long) arg3;
-}
 
-static void setup_frame(int sig, struct k_sigaction *ka,
+static void setup_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
 			sigset_t *set, struct pt_regs *regs)
 {
-	struct sigframe *frame;
+	struct rt_sigframe *frame;
 	int err = 0;
 	int signal;
+	unsigned long sp, ra;
 
-	frame = get_sigframe(ka, regs->areg[1], sizeof(*frame));
-	if (regs->depc > 64)
-	{
-		printk("!!!!!!! DEPC !!!!!!!\n");
-		return;
-	}
-
-
-	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
-		goto give_sigsegv;
-
-	signal = current_thread_info()->exec_domain
-		&& current_thread_info()->exec_domain->signal_invmap
-		&& sig < 32
-		? current_thread_info()->exec_domain->signal_invmap[sig]
-		: sig;
-
-	err |= setup_sigcontext(&frame->sc, &frame->cpstate, regs, set->sig[0]);
+	sp = regs->areg[1];
 
-	if (_NSIG_WORDS > 1) {
-		err |= __copy_to_user(frame->extramask, &set->sig[1],
-				      sizeof(frame->extramask));
+	if ((ka->sa.sa_flags & SA_ONSTACK) != 0 && ! on_sig_stack(sp)) {
+		sp = current->sas_ss_sp + current->sas_ss_size;
 	}
 
-	/* Create sys_sigreturn syscall in stack frame */
-	err |= gen_return_code(frame->retcode, USE_SIGRETURN);
-
-	if (err)
-		goto give_sigsegv;
-
-	/* Create signal handler execution context.
-	 * Return context not modified until this point.
-	 */
-	set_thread_state(regs, frame, frame->retcode,
-		ka->sa.sa_handler, signal, &frame->sc, NULL);
-
-	/* Set access mode to USER_DS.  Nomenclature is outdated, but
-	 * functionality is used in uaccess.h
-	 */
-	set_fs(USER_DS);
-
-
-#if DEBUG_SIG
-	printk("SIG deliver (%s:%d): signal=%d sp=%p pc=%08x\n",
-		current->comm, current->pid, signal, frame, regs->pc);
-#endif
-
-	return;
-
-give_sigsegv:
-	if (sig == SIGSEGV)
-		ka->sa.sa_handler = SIG_DFL;
-	force_sig(SIGSEGV, current);
-}
-
-static void setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
-			   sigset_t *set, struct pt_regs *regs)
-{
-	struct rt_sigframe *frame;
-	int err = 0;
-	int signal;
+	frame = (void *)((sp - sizeof(*frame)) & -16ul);
 
-	frame = get_sigframe(ka, regs->areg[1], sizeof(*frame));
 	if (regs->depc > 64)
 		panic ("Double exception sys_sigreturn\n");
 
-	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
+	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) {
 		goto give_sigsegv;
+	}
 
 	signal = current_thread_info()->exec_domain
 		&& current_thread_info()->exec_domain->signal_invmap
@@ -602,9 +347,12 @@ static void setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
 		? current_thread_info()->exec_domain->signal_invmap[sig]
 		: sig;
 
-	err |= copy_siginfo_to_user(&frame->info, info);
+	if (ka->sa.sa_flags & SA_SIGINFO) {
+		err |= copy_siginfo_to_user(&frame->info, info);
+	}
+
+	/* Create the user context.  */
 
-	/* Create the ucontext.  */
 	err |= __put_user(0, &frame->uc.uc_flags);
 	err |= __put_user(0, &frame->uc.uc_link);
 	err |= __put_user((void *)current->sas_ss_sp,
@@ -617,16 +365,31 @@ static void setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
 	err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
 
 	/* Create sys_rt_sigreturn syscall in stack frame */
-	err |= gen_return_code(frame->retcode, USE_RT_SIGRETURN);
 
-	if (err)
+	err |= gen_return_code(frame->retcode);
+
+	if (err) {
 		goto give_sigsegv;
+	}
+		
 
-	/* Create signal handler execution context.
+	/* 
+	 * Create signal handler execution context.
 	 * Return context not modified until this point.
 	 */
-	set_thread_state(regs, frame, frame->retcode,
-		ka->sa.sa_handler, signal, &frame->info, &frame->uc);
+
+	/* Set up registers for signal handler */
+	start_thread(regs, (unsigned long) ka->sa.sa_handler, 
+		     (unsigned long) frame);
+
+	/* Set up a stack frame for a call4
+	 * Note: PS.CALLINC is set to one by start_thread
+	 */
+	ra = (unsigned long) frame->retcode;
+	regs->areg[4] = (((unsigned long) ra) & 0x3fffffff) | 0x40000000;
+	regs->areg[6] = (unsigned long) signal;
+	regs->areg[7] = (unsigned long) &frame->info;
+	regs->areg[8] = (unsigned long) &frame->uc;
 
 	/* Set access mode to USER_DS.  Nomenclature is outdated, but
 	 * functionality is used in uaccess.h
@@ -646,6 +409,48 @@ give_sigsegv:
 	force_sig(SIGSEGV, current);
 }
 
+/*
+ * 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);
+	spin_lock_irq(&current->sighand->siglock);
+	saveset = current->blocked;
+	current->blocked = newset;
+	recalc_sigpending();
+	spin_unlock_irq(&current->sighand->siglock);
+
+	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,
+				   struct pt_regs *regs)
+{
+	return do_sigaltstack(uss, uoss, regs->areg[1]);
+}
+
 
 
 /*
@@ -663,51 +468,89 @@ int do_signal(struct pt_regs *regs, sigset_t *oldset)
 	int signr;
 	struct k_sigaction ka;
 
+	if (!user_mode(regs))
+		return 0;
+
+	if (try_to_freeze())
+		goto no_signal;
+
 	if (!oldset)
 		oldset = &current->blocked;
 
+	task_pt_regs(current)->icountlevel = 0;
+
 	signr = get_signal_to_deliver(&info, &ka, regs, NULL);
 
-	/* Are we from a system call? */
-	if (regs->syscall >= 0) {
-		/* If so, check system call restarting.. */
-		switch (regs->areg[2]) {
-			case ERESTARTNOHAND:
-			case ERESTART_RESTARTBLOCK:
-				regs->areg[2] = -EINTR;
-				break;
+	if (signr > 0) {
+
+		/* Are we from a system call? */
+
+		if ((signed)regs->syscall >= 0) {
 
-			case ERESTARTSYS:
-				if (!(ka.sa.sa_flags & SA_RESTART)) {
+			/* If so, check system call restarting.. */
+
+			switch (regs->areg[2]) {
+				case -ERESTARTNOHAND:
+				case -ERESTART_RESTARTBLOCK:
 					regs->areg[2] = -EINTR;
 					break;
-				}
-			/* fallthrough */
-			case ERESTARTNOINTR:
-				regs->areg[2] = regs->syscall;
-				regs->pc -= 3;
+
+				case -ERESTARTSYS:
+					if (!(ka.sa.sa_flags & SA_RESTART)) {
+						regs->areg[2] = -EINTR;
+						break;
+					}
+					/* fallthrough */
+				case -ERESTARTNOINTR:
+					regs->areg[2] = regs->syscall;
+					regs->pc -= 3;
+					break;
+
+				default:
+					/* nothing to do */
+					if (regs->areg[2] != 0)
+					break;
+			}
 		}
-	}
 
-	if (signr == 0)
-		return 0;		/* no signals delivered */
+		/* Whee!  Actually deliver the signal.  */
+		/* Set up the stack frame */
+		setup_frame(signr, &ka, &info, oldset, regs);
 
-	/* Whee!  Actually deliver the signal.  */
+		if (ka.sa.sa_flags & SA_ONESHOT)
+			ka.sa.sa_handler = SIG_DFL;
 
-	/* Set up the stack frame */
-	if (ka.sa.sa_flags & SA_SIGINFO)
-		setup_rt_frame(signr, &ka, &info, oldset, regs);
-	else
-		setup_frame(signr, &ka, oldset, regs);
+		spin_lock_irq(&current->sighand->siglock);
+		sigorsets(&current->blocked, &current->blocked, &ka.sa.sa_mask);
+		if (!(ka.sa.sa_flags & SA_NODEFER))
+			sigaddset(&current->blocked, signr);
+		recalc_sigpending();
+		spin_unlock_irq(&current->sighand->siglock);
+		if (current->ptrace & PT_SINGLESTEP)
+			task_pt_regs(current)->icountlevel = 1;
 
-	if (ka.sa.sa_flags & SA_ONESHOT)
-		ka.sa.sa_handler = SIG_DFL;
+		return 1;
+	}
 
-	spin_lock_irq(&current->sighand->siglock);
-	sigorsets(&current->blocked, &current->blocked, &ka.sa.sa_mask);
-	if (!(ka.sa.sa_flags & SA_NODEFER))
-		sigaddset(&current->blocked, signr);
-	recalc_sigpending();
-	spin_unlock_irq(&current->sighand->siglock);
-	return 1;
+no_signal:
+	/* Did we come from a system call? */
+	if ((signed) regs->syscall >= 0) {
+		/* Restart the system call - no handlers present */
+		switch (regs->areg[2]) {
+		case -ERESTARTNOHAND:
+		case -ERESTARTSYS:
+		case -ERESTARTNOINTR:
+			regs->areg[2] = regs->syscall;
+			regs->pc -= 3;
+			break;
+		case -ERESTART_RESTARTBLOCK:
+			regs->areg[2] = __NR_restart_syscall;
+			regs->pc -= 3;
+			break;
+		}
+	}
+	if (current->ptrace & PT_SINGLESTEP)
+		task_pt_regs(current)->icountlevel = 1;
+	return 0;
 }
+