[PATCH 2 of 4] unmodified_drivers: add pfn_is_ram helper for kdump

[Olaf Hering <olaf@aepfle.de>]

# HG changeset patch
# User Olaf Hering <olaf@aepfle.de>
# Date 1331883706 -3600
# Node ID dacdcaaf113263ee748bef99d175b1b7e7013be5
# Parent  5504366919926f8a2d6fc7fdc392e6218ae6c702
unmodified_drivers: add pfn_is_ram helper for kdump

Register pfn_is_ram helper speed up reading /proc/vmcore in the kdump
kernel. It is compiled only if the kernel source is recent enough to
have the pfn_is_ram helper (v3.0-rc1, commit
997c136f518c5debd63847e78e2a8694f56dcf90).

Signed-off-by: Olaf Hering <olaf@aepfle.de>

diff -r 550436691992 -r dacdcaaf1132 unmodified_drivers/linux-2.6/platform-pci/platform-pci.c
--- a/unmodified_drivers/linux-2.6/platform-pci/platform-pci.c
+++ b/unmodified_drivers/linux-2.6/platform-pci/platform-pci.c
@@ -351,6 +351,32 @@ static int check_platform_magic(struct d
 	return -ENODEV;
 }
 
+#if defined(HAVE_OLDMEM_PFN_IS_RAM)
+static int xen_oldmem_pfn_is_ram(unsigned long pfn)
+{
+	struct xen_hvm_get_mem_type a;
+	int ret;
+
+	a.domid = DOMID_SELF;
+	a.pfn = pfn;
+	if (HYPERVISOR_hvm_op(HVMOP_get_mem_type, &a))
+		return -ENXIO;
+
+	switch (a.mem_type) {
+		case HVMMEM_mmio_dm:
+			ret = 0;
+			break;
+		case HVMMEM_ram_rw:
+		case HVMMEM_ram_ro:
+		default:
+			ret = 1;
+			break;
+	}
+
+	return ret;
+}
+#endif
+
 static int __devinit platform_pci_init(struct pci_dev *pdev,
 				       const struct pci_device_id *ent)
 {
@@ -419,6 +445,9 @@ static int __devinit platform_pci_init(s
 	if ((ret = xen_panic_handler_init()))
 		goto out;
 
+#if defined(HAVE_OLDMEM_PFN_IS_RAM)
+	register_oldmem_pfn_is_ram(&xen_oldmem_pfn_is_ram);
+#endif
  out:
 	if (ret) {
 		pci_release_region(pdev, 0);