Support for non-exec mappings on sun4m.

 - support exec traps and deal with them correctly.
 - Instead of pretending that the pte permissions are a bit-mask, just
   make two stupid 8-entry tables (one for kernel, one for userland) that
   provides translation between VM_PROT* masks and pte permissions.

This gives sun4m a non-exec stack.

2 files changed, 69 insertions, 12 deletions

diff --git a/sys/arch/sparc/sparc/pmap.c b/sys/arch/sparc/sparc/pmap.c
index 62dbd1a402a..ae9897b5aa5 100644
--- a/sys/arch/sparc/sparc/pmap.c
+++ b/sys/arch/sparc/sparc/pmap.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: pmap.c,v 1.125 2002/07/09 18:08:18 art Exp $	*/
+/*	$OpenBSD: pmap.c,v 1.126 2002/07/24 00:55:52 art Exp $	*/
 /*	$NetBSD: pmap.c,v 1.118 1998/05/19 19:00:18 thorpej Exp $ */
 
 /*
@@ -653,6 +653,58 @@ setpte4m(va, pte)
 	setpgt4m(ptep, pte);
 }
 
+/*
+ * Translation table for kernel vs. PTE protection bits.
+ */
+u_int protection_codes[2][8];
+#define pte_prot4m(pm, prot) (protection_codes[pm == pmap_kernel()?0:1][prot])
+
+static void
+sparc_protection_init4m(void)
+{
+	u_int prot, *kp, *up;
+
+	kp = protection_codes[0];
+	up = protection_codes[1];
+
+	for (prot = 0; prot < 8; prot++) {
+		switch (prot) {
+		case VM_PROT_READ | VM_PROT_WRITE | VM_PROT_EXECUTE:
+			kp[prot] = PPROT_N_RWX;
+			up[prot] = PPROT_RWX_RWX;
+			break;
+		case VM_PROT_READ | VM_PROT_WRITE | VM_PROT_NONE:
+			kp[prot] = PPROT_N_RWX;
+			up[prot] = PPROT_RW_RW;
+			break;
+		case VM_PROT_READ | VM_PROT_NONE  | VM_PROT_EXECUTE:
+			kp[prot] = PPROT_N_RX;
+			up[prot] = PPROT_RX_RX;
+			break;
+		case VM_PROT_READ | VM_PROT_NONE  | VM_PROT_NONE:
+			kp[prot] = PPROT_N_RX;
+			up[prot] = PPROT_R_R;
+			break;
+		case VM_PROT_NONE | VM_PROT_WRITE | VM_PROT_EXECUTE:
+			kp[prot] = PPROT_N_RWX;
+			up[prot] = PPROT_RWX_RWX;
+			break;
+		case VM_PROT_NONE | VM_PROT_WRITE | VM_PROT_NONE:
+			kp[prot] = PPROT_N_RWX;
+			up[prot] = PPROT_RW_RW;
+			break;
+		case VM_PROT_NONE | VM_PROT_NONE  | VM_PROT_EXECUTE:
+			kp[prot] = PPROT_N_RX;
+			up[prot] = PPROT_X_X;
+			break;
+		case VM_PROT_NONE | VM_PROT_NONE  | VM_PROT_NONE:
+			kp[prot] = PPROT_N_RX;
+			up[prot] = PPROT_R_R;
+			break;
+		}
+	}
+}
+
 #endif /* 4m only */
 
 /*----------------------------------------------------------------*/
@@ -3217,6 +3269,7 @@ pmap_bootstrap4m(void)
 	mmu_install_tables(&cpuinfo);
 
 	pmap_page_upload(avail_start);
+	sparc_protection_init4m();
 }
 
 void
@@ -4781,10 +4834,7 @@ pmap_changeprot4m(pm, va, prot, wired)
 	write_user_windows();	/* paranoia */
 
 	va = trunc_page(va);
-	if (pm == pmap_kernel())
-		newprot = prot & VM_PROT_WRITE ? PPROT_N_RWX : PPROT_N_RX;
-	else
-		newprot = prot & VM_PROT_WRITE ? PPROT_RWX_RWX : PPROT_RX_RX;
+	newprot = pte_prot4m(pm, prot);
 
 	pmap_stats.ps_changeprots++;
 
@@ -5238,8 +5288,7 @@ pmap_enter4m(pm, va, pa, prot, flags)
 #endif
 	pteproto |= PMAP_T2PTE_SRMMU(pa);
 
-	/* Make sure we get a pte with appropriate perms! */
-	pteproto |= SRMMU_TEPTE | PPROT_RX_RX;
+	pteproto |= SRMMU_TEPTE;
 
 	pa &= ~PMAP_TNC_SRMMU;
 	/*
@@ -5254,12 +5303,12 @@ pmap_enter4m(pm, va, pa, prot, flags)
 
 	pteproto |= (atop(pa) << SRMMU_PPNSHIFT);
 
-	if (prot & VM_PROT_WRITE)
-		pteproto |= PPROT_WRITE;
+	/* correct protections */
+	pteproto |= pte_prot4m(pm, prot);
 
 	ctx = getcontext4m();
 	if (pm == pmap_kernel())
-		ret = pmap_enk4m(pm, va, prot, flags, pv, pteproto | PPROT_S);
+		ret = pmap_enk4m(pm, va, prot, flags, pv, pteproto);
 	else
 		ret = pmap_enu4m(pm, va, prot, flags, pv, pteproto);
 #ifdef DIAGNOSTIC
diff --git a/sys/arch/sparc/sparc/trap.c b/sys/arch/sparc/sparc/trap.c
index d0d57e22c43..381fe7c1739 100644
--- a/sys/arch/sparc/sparc/trap.c
+++ b/sys/arch/sparc/sparc/trap.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: trap.c,v 1.38 2002/05/16 21:11:18 miod Exp $	*/
+/*	$OpenBSD: trap.c,v 1.39 2002/07/24 00:55:52 art Exp $	*/
 /*	$NetBSD: trap.c,v 1.58 1997/09/12 08:55:01 pk Exp $ */
 
 /*
@@ -861,7 +861,15 @@ mem_access_fault4m(type, sfsr, sfva, tf)
 	if ((sfsr & SFSR_FT) == SFSR_FT_NONE)
 		goto out;	/* No fault. Why were we called? */
 
-	ftype = sfsr & SFSR_AT_STORE ? VM_PROT_WRITE : VM_PROT_READ;
+	if ((sfsr & SFSR_AT_STORE)) {
+		/* stores are never text faults. */
+		ftype = VM_PROT_WRITE;
+	} else {
+		ftype = VM_PROT_READ;
+		if ((sfsr & SFSR_AT_TEXT) || (type == T_TEXTFAULT)) {
+			ftype |= VM_PROT_EXECUTE;
+		}
+	}
 
 	/*
 	 * NOTE: the per-CPU fault status register readers (in locore)