Switch the amd64 PCI_CONF_LOCK from being a simplelock and splhigh to a

mutex with ipl set to IPL_HIGH. While i'm here, unify the code with
i386, by giving the same lock to the i386 code.

This lock is mostly for MP, but could actually prevent a race where a
process is doing pci_conf_{read,write}, and then an interrupt fire and
also does pci_conf_{read,write}. Since this is a two stage process, the
interrupt could race with the one, causing the value to the written to
the wrong place, or the wrong value to be written.

Tested by many. "go ahead" kettenis@.

2 files changed, 27 insertions, 19 deletions

diff --git a/sys/arch/amd64/pci/pci_machdep.c b/sys/arch/amd64/pci/pci_machdep.c
index 85a4b1013b1..a11c8cd2ebe 100644
--- a/sys/arch/amd64/pci/pci_machdep.c
+++ b/sys/arch/amd64/pci/pci_machdep.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: pci_machdep.c,v 1.20 2008/12/28 18:26:53 kettenis Exp $	*/
+/*	$OpenBSD: pci_machdep.c,v 1.21 2009/01/27 15:33:59 oga Exp $	*/
 /*	$NetBSD: pci_machdep.c,v 1.3 2003/05/07 21:33:58 fvdl Exp $	*/
 
 /*-
@@ -105,22 +105,16 @@
 
 int pci_mode = -1;
 
-#if defined(MULTIPROCESSOR) && 0
-struct simplelock pci_conf_slock = SIMPLELOCK_INITIALIZER;
-#else
-struct simplelock pci_conf_slock = { 0 };
-#endif
+struct mutex pci_conf_lock = MUTEX_INITIALIZER(IPL_HIGH);
 
-#define	PCI_CONF_LOCK(s)						\
+#define	PCI_CONF_LOCK()						\
 do {									\
-	(s) = splhigh();						\
-	simple_lock(&pci_conf_slock);					\
+	mtx_enter(&pci_conf_lock);					\
 } while (0)
 
-#define	PCI_CONF_UNLOCK(s)						\
+#define	PCI_CONF_UNLOCK()						\
 do {									\
-	simple_unlock(&pci_conf_slock);					\
-	splx((s));							\
+	mtx_leave(&pci_conf_lock);					\
 } while (0)
 
 #define	PCI_MODE1_ENABLE	0x80000000UL
@@ -258,9 +252,8 @@ pcireg_t
 pci_conf_read(pci_chipset_tag_t pc, pcitag_t tag, int reg)
 {
 	pcireg_t data;
-	int s;
 
-	PCI_CONF_LOCK(s);
+	PCI_CONF_LOCK();
 	switch (pci_mode) {
 	case 1:
 		outl(PCI_MODE1_ADDRESS_REG, tag.mode1 | reg);
@@ -276,7 +269,7 @@ pci_conf_read(pci_chipset_tag_t pc, pcitag_t tag, int reg)
 	default:
 		panic("pci_conf_read: mode not configured");
 	}
-	PCI_CONF_UNLOCK(s);
+	PCI_CONF_UNLOCK();
 
 	return data;
 }
@@ -284,9 +277,8 @@ pci_conf_read(pci_chipset_tag_t pc, pcitag_t tag, int reg)
 void
 pci_conf_write(pci_chipset_tag_t pc, pcitag_t tag, int reg, pcireg_t data)
 {
-	int s;
 
-	PCI_CONF_LOCK(s);
+	PCI_CONF_LOCK();
 	switch (pci_mode) {
 	case 1:
 		outl(PCI_MODE1_ADDRESS_REG, tag.mode1 | reg);
@@ -302,7 +294,7 @@ pci_conf_write(pci_chipset_tag_t pc, pcitag_t tag, int reg, pcireg_t data)
 	default:
 		panic("pci_conf_write: mode not configured");
 	}
-	PCI_CONF_UNLOCK(s);
+	PCI_CONF_UNLOCK();
 }
 
 int
diff --git a/sys/arch/i386/pci/pci_machdep.c b/sys/arch/i386/pci/pci_machdep.c
index 5954a8152b9..ebe9a4f9ad7 100644
--- a/sys/arch/i386/pci/pci_machdep.c
+++ b/sys/arch/i386/pci/pci_machdep.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: pci_machdep.c,v 1.43 2008/12/28 18:26:53 kettenis Exp $	*/
+/*	$OpenBSD: pci_machdep.c,v 1.44 2009/01/27 15:33:59 oga Exp $	*/
 /*	$NetBSD: pci_machdep.c,v 1.28 1997/06/06 23:29:17 thorpej Exp $	*/
 
 /*-
@@ -113,6 +113,18 @@ extern bios_pciinfo_t *bios_pciinfo;
 
 int pci_mode = -1;
 
+struct mutex pci_conf_lock = MUTEX_INITIALIZER(IPL_HIGH);
+
+#define	PCI_CONF_LOCK()							\
+do {									\
+	mtx_enter(&pci_conf_lock);					\
+} while (0)
+
+#define	PCI_CONF_UNLOCK()						\
+do {									\
+	mtx_leave(&pci_conf_lock);					\
+} while (0)
+
 #define	PCI_MODE1_ENABLE	0x80000000UL
 #define	PCI_MODE1_ADDRESS_REG	0x0cf8
 #define	PCI_MODE1_DATA_REG	0x0cfc
@@ -252,6 +264,7 @@ pci_conf_read(pci_chipset_tag_t pc, pcitag_t tag, int reg)
 {
 	pcireg_t data;
 
+	PCI_CONF_LOCK();
 	switch (pci_mode) {
 	case 1:
 		outl(PCI_MODE1_ADDRESS_REG, tag.mode1 | reg);
@@ -267,6 +280,7 @@ pci_conf_read(pci_chipset_tag_t pc, pcitag_t tag, int reg)
 	default:
 		panic("pci_conf_read: mode not configured");
 	}
+	PCI_CONF_UNLOCK();
 
 	return data;
 }
@@ -275,6 +289,7 @@ void
 pci_conf_write(pci_chipset_tag_t pc, pcitag_t tag, int reg, pcireg_t data)
 {
 
+	PCI_CONF_LOCK();
 	switch (pci_mode) {
 	case 1:
 		outl(PCI_MODE1_ADDRESS_REG, tag.mode1 | reg);
@@ -290,6 +305,7 @@ pci_conf_write(pci_chipset_tag_t pc, pcitag_t tag, int reg, pcireg_t data)
 	default:
 		panic("pci_conf_write: mode not configured");
 	}
+	PCI_CONF_UNLOCK();
 }
 
 int