svn commit: r189373 - head/sys/dev/pci
John Baldwin
jhb at FreeBSD.org
Wed Mar 4 13:04:54 PST 2009
Author: jhb
Date: Wed Mar 4 21:04:52 2009
New Revision: 189373
URL: http://svn.freebsd.org/changeset/base/189373
Log:
The recent PCI resource allocation fixes exposed a bug where the same
BAR could be allocated twice by different children of a vgapci0 device.
To fix this, change the vgapci0 device to track references on its associated
resources so that they are only allocated once from the parent PCI bus and
released when no children are using them. Previously this leaked a small
amount of KVA on at least some architectures.
Modified:
head/sys/dev/pci/vga_pci.c
Modified: head/sys/dev/pci/vga_pci.c
==============================================================================
--- head/sys/dev/pci/vga_pci.c Wed Mar 4 20:58:22 2009 (r189372)
+++ head/sys/dev/pci/vga_pci.c Wed Mar 4 21:04:52 2009 (r189373)
@@ -42,12 +42,20 @@ __FBSDID("$FreeBSD$");
#include <sys/bus.h>
#include <sys/kernel.h>
#include <sys/module.h>
+#include <sys/rman.h>
+#include <sys/systm.h>
#include <dev/pci/pcireg.h>
#include <dev/pci/pcivar.h>
+struct vga_resource {
+ struct resource *vr_res;
+ int vr_refs;
+};
+
struct vga_pci_softc {
device_t vga_msi_child; /* Child driver using MSI. */
+ struct vga_resource vga_res[PCIR_MAX_BAR_0 + 1];
};
static int
@@ -130,7 +138,27 @@ static struct resource *
vga_pci_alloc_resource(device_t dev, device_t child, int type, int *rid,
u_long start, u_long end, u_long count, u_int flags)
{
+ struct vga_pci_softc *sc;
+ int bar;
+ switch (type) {
+ case SYS_RES_MEMORY:
+ case SYS_RES_IOPORT:
+ /*
+ * For BARs, we cache the resource so that we only allocate it
+ * from the PCI bus once.
+ */
+ bar = PCI_RID2BAR(*rid);
+ if (bar < 0 || bar > PCIR_MAX_BAR_0)
+ return (NULL);
+ sc = device_get_softc(dev);
+ if (sc->vga_res[bar].vr_res == NULL)
+ sc->vga_res[bar].vr_res = bus_alloc_resource(dev, type,
+ rid, start, end, count, flags);
+ if (sc->vga_res[bar].vr_res != NULL)
+ sc->vga_res[bar].vr_refs++;
+ return (sc->vga_res[bar].vr_res);
+ }
return (bus_alloc_resource(dev, type, rid, start, end, count, flags));
}
@@ -138,6 +166,37 @@ static int
vga_pci_release_resource(device_t dev, device_t child, int type, int rid,
struct resource *r)
{
+ struct vga_pci_softc *sc;
+ int bar, error;
+
+ switch (type) {
+ case SYS_RES_MEMORY:
+ case SYS_RES_IOPORT:
+ /*
+ * For BARs, we release the resource from the PCI bus
+ * when the last child reference goes away.
+ */
+ bar = PCI_RID2BAR(rid);
+ if (bar < 0 || bar > PCIR_MAX_BAR_0)
+ return (EINVAL);
+ sc = device_get_softc(dev);
+ if (sc->vga_res[bar].vr_res == NULL)
+ return (EINVAL);
+ KASSERT(sc->vga_res[bar].vr_res == r,
+ ("vga_pci resource mismatch"));
+ if (sc->vga_res[bar].vr_refs > 1) {
+ sc->vga_res[bar].vr_refs--;
+ return (0);
+ }
+ KASSERT(sc->vga_res[bar].vr_refs > 0,
+ ("vga_pci resource reference count underflow"));
+ error = bus_release_resource(dev, type, rid, r);
+ if (error == 0) {
+ sc->vga_res[bar].vr_res = NULL;
+ sc->vga_res[bar].vr_refs = 0;
+ }
+ return (error);
+ }
return (bus_release_resource(dev, type, rid, r));
}
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