Determine whether we're currently on the alternative signal stack

dynamically, by comparing the stack pointer against the altstack
base and size, so that you get the correct answer if you longjmp
out of the signal handler, as tested by regress/sys/kern/stackjmp/.
Also, fix alt stack handling on vax, where it was completely broken.

Testing and corrections by miod@, krw@, tobiasu@, pirofti@

3 files changed, 10 insertions, 18 deletions

diff --git a/sys/arch/sh/include/cpu.h b/sys/arch/sh/include/cpu.h
index 2963065e1f5..021ab7203ff 100644
--- a/sys/arch/sh/include/cpu.h
+++ b/sys/arch/sh/include/cpu.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: cpu.h,v 1.21 2010/09/28 20:27:55 miod Exp $	*/
+/*	$OpenBSD: cpu.h,v 1.22 2012/12/02 07:03:31 guenther Exp $	*/
 /*	$NetBSD: cpu.h,v 1.41 2006/01/21 04:24:12 uwe Exp $	*/
 
 /*-
@@ -97,8 +97,8 @@ struct clockframe {
  * This is used during profiling to integrate system time.  It can safely
  * assume that the process is resident.
  */
-#define	PROC_PC(p)							\
-	(((struct trapframe *)(p)->p_md.md_regs)->tf_spc)
+#define	PROC_PC(p)	((p)->p_md.md_regs->tf_spc)
+#define	PROC_STACK(p)	((p)->p_md.md_regs->tf_r15)
 
 /*
  * Preempt the current process if in interrupt from user mode,
diff --git a/sys/arch/sh/include/signal.h b/sys/arch/sh/include/signal.h
index 7f123772a2d..e5152d73cf2 100644
--- a/sys/arch/sh/include/signal.h
+++ b/sys/arch/sh/include/signal.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: signal.h,v 1.5 2012/04/27 17:39:47 pirofti Exp $	*/
+/*	$OpenBSD: signal.h,v 1.6 2012/12/02 07:03:31 guenther Exp $	*/
 /*	$NetBSD: signal.h,v 1.12 2005/12/11 12:18:58 christos Exp $	*/
 
 /*
@@ -52,7 +52,7 @@ struct sigcontext {
 	int	sc_reg[21];
 	int	sc_fpreg[34];
 
-	int	sc_onstack;	/* sigstack state to restore */
+	int	__sc_unused;
 
 	int	sc_expevt;	/* XXX should be above */
 	int	sc_err;
diff --git a/sys/arch/sh/sh/sh_machdep.c b/sys/arch/sh/sh/sh_machdep.c
index 28d96a9a250..99342ff17c5 100644
--- a/sys/arch/sh/sh/sh_machdep.c
+++ b/sys/arch/sh/sh/sh_machdep.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: sh_machdep.c,v 1.32 2012/04/13 18:09:01 miod Exp $	*/
+/*	$OpenBSD: sh_machdep.c,v 1.33 2012/12/02 07:03:31 guenther Exp $	*/
 /*	$NetBSD: sh3_machdep.c,v 1.59 2006/03/04 01:13:36 uwe Exp $	*/
 
 /*
@@ -462,15 +462,13 @@ sendsig(sig_t catcher, int sig, int mask, u_long code, int type,
 	struct trapframe *tf = p->p_md.md_regs;
 	struct sigacts *psp = p->p_sigacts;
 	siginfo_t *sip;
-	int onstack;
 
-	onstack = p->p_sigstk.ss_flags & SS_ONSTACK;
-	if ((p->p_sigstk.ss_flags & SS_DISABLE) == 0 && onstack == 0 &&
-	    (psp->ps_sigonstack & sigmask(sig))) {
+	if ((p->p_sigstk.ss_flags & SS_DISABLE) == 0 &&
+	    !sigonstack(p->p_md.md_regs->tf_r15) &&
+	    (psp->ps_sigonstack & sigmask(sig)))
 		fp = (struct sigframe *)((vaddr_t)p->p_sigstk.ss_sp +
 		    p->p_sigstk.ss_size);
-		p->p_sigstk.ss_flags |= SS_ONSTACK;
-	} else
+	else
 		fp = (void *)p->p_md.md_regs->tf_r15;
 	--fp;
 
@@ -490,7 +488,6 @@ sendsig(sig_t catcher, int sig, int mask, u_long code, int type,
 		fpu_save((struct fpreg *)&frame.sf_uc.sc_fpreg);
 #endif
 
-	frame.sf_uc.sc_onstack = onstack;
 	frame.sf_uc.sc_expevt = tf->tf_expevt;
 	/* frame.sf_uc.sc_err = 0; */
 	frame.sf_uc.sc_mask = mask;
@@ -555,11 +552,6 @@ sys_sigreturn(struct proc *p, void *v, register_t *retval)
 		fpu_restore((struct fpreg *)&context.sc_fpreg);
 #endif
 
-	/* Restore signal stack. */
-	if (context.sc_onstack)
-		p->p_sigstk.ss_flags |= SS_ONSTACK;
-	else
-		p->p_sigstk.ss_flags &= ~SS_ONSTACK;
 	/* Restore signal mask. */
 	p->p_sigmask = context.sc_mask & ~sigcantmask;