[PATCH 3/5] x86: avoid PNP resources when allocating address space

Bjorn Helgaas
2010-12-08T21:36:19Z

Remove PNP resources from "available space" used by allocate_resource().
This would be better done by putting the PNP resources directly in the
resource maps (iomem_resource, etc), but there are some issues that
keep us from doing that yet.

This patch keeps us from handing out PNP device address space to other
callers of allocate_resource().

Reference: https://bugzilla.kernel.org/show_bug.cgi?id=23332
Reference: https://bugzilla.kernel.org/show_bug.cgi?id=23542
Reference: https://bugzilla.kernel.org/show_bug.cgi?id=23802
Reported-by: Matthew Garrett <mjg@redhat.com>
Reported-by: Dan Williams <dcbw@redhat.com>
Reported-by: Jiri Slaby <jirislaby@gmail.com>
Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
---

arch/x86/kernel/resource.c | 78 ++++++++++++++++++++++++++++++++++++++++++++
1 files changed, 78 insertions(+), 0 deletions(-)

diff --git a/arch/x86/kernel/resource.c b/arch/x86/kernel/resource.c
index 5dd6473..1daee92 100644
--- a/arch/x86/kernel/resource.c
+++ b/arch/x86/kernel/resource.c
@@ -1,6 +1,80 @@
#include <linux/ioport.h>
+#include <linux/pnp.h>
#include <asm/e820.h>

+#ifdef CONFIG_PNP
+static bool resource_conflict(struct resource *res, resource_size_t start,
+ resource_size_t end)
+{
+ /*
+ * Return true if and only if "res" conflicts with the [start-end]
+ * range.
+ */
+ return res->start <= end && res->end >= start;
+}
+
+static void resource_split(struct resource *res, resource_size_t start,
+ resource_size_t end, struct resource *low,
+ struct resource *high)
+{
+ /*
+ * If "res" conflicts with [start-end], split "res" into the
+ * part below "start" (low) and the part above "end" (high),
+ * either (or both) of which may be empty.
+ *
+ * If there's no conflict, return the entire "res" as "low".
+ */
+ *low = *res;
+ low->start = res->start;
+ low->end = res->start - 1; /* default to empty (size 0) */
+
+ *high = *res;
+ high->end = res->end;
+ high->start = res->end + 1; /* default to empty (size 0) */
+
+ if (!resource_conflict(res, start, end)) {
+ low->end = res->end;
+ return;
+ }
+
+ if (res->start < start)
+ low->end = start - 1;
+
+ if (res->end > end)
+ high->start = end + 1;
+}
+
+static void pnp_remove_reservations(struct resource *avail)
+{
+ unsigned long type = resource_type(avail);
+ struct pnp_dev *dev;
+ int i;
+ struct resource *res, low, high;
+
+ /*
+ * Clip the available region to avoid PNP devices. The PNP
+ * resources really should be in the resource map to begin with,
+ * but there are still some issues preventing that.
+ */
+ pnp_for_each_dev(dev) {
+ i = 0;
+ res = pnp_get_resource(dev, type, i++);
+ while (res) {
+ if (!(res->flags & IORESOURCE_WINDOW)) {
+ resource_split(avail, res->start, res->end,
+ &low, &high);
+ if (resource_size(&low) > resource_size(&high))
+ *avail = low;
+ else
+ *avail = high;
+ }
+
+ res = pnp_get_resource(dev, type, i++);
+ }
+ }
+}
+#endif
+
void arch_remove_reservations(struct resource *avail)
{
/*
@@ -11,4 +85,8 @@ void arch_remove_reservations(struct resource *avail)
if (avail->start < BIOS_END)
avail->start = BIOS_END;
}
+
+#ifdef CONFIG_PNP
+ pnp_remove_reservations(avail);
+#endif
}