Register memory regions reserved by UEFI as IORESOURCE_MEM resources,
so that they are reserved for other uses, and also makes them turn up
in /proc/iomem.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
---
drivers/firmware/efi/virtmap.c | 36 ++++++++++++++++++++++++++++++++++++
1 file changed, 36 insertions(+)
diff --git a/drivers/firmware/efi/virtmap.c b/drivers/firmware/efi/virtmap.c
index d1f1d416944f..98735fb43581 100644
--- a/drivers/firmware/efi/virtmap.c
+++ b/drivers/firmware/efi/virtmap.c
@@ -13,6 +13,7 @@
#include <linux/rwsem.h>
#include <linux/spinlock.h>
#include <linux/atomic.h>
+#include <linux/bootmem.h>
#include <asm/efi.h>
#include <asm/pgtable.h>
@@ -52,6 +53,39 @@ static pgprot_t efi_md_access_prot(efi_memory_desc_t *md, pgprot_t prot)
return pgprot_device(prot);
}
+static __init void efi_register_mem_resource(efi_memory_desc_t *md)
+{
+ struct resource *res, *parent;
+
+ res = alloc_bootmem_low(sizeof(*res));
+ res->start = md->phys_addr;
+ res->end = res->start + (md->num_pages << EFI_PAGE_SHIFT) - 1;
+ res->flags = IORESOURCE_MEM;
+
+ if (md->type == EFI_MEMORY_MAPPED_IO &&
+ (md->attribute & EFI_MEMORY_RUNTIME)) {
+ /*
+ * Device regions with the EFI_MEMORY_RUNTIME attribute
+ * are owned by the UEFI firmware, so make sure they are
+ * tagged as exclusive: this will also prevent access
+ * via /dev/mem if CONFIG_STRICT_DEVMEM is in effect.
+ */
+ res->name = "UEFI Runtime I/O";
+ res->flags |= IORESOURCE_EXCLUSIVE;
+ } else {
+ res->name = "UEFI Reserved";
+ }
+
+ /*
+ * Try to register this resource at the top level. If it conflicts with
+ * an existing entry ('System RAM', most likely), register it as its
+ * child instead.
+ */
+ parent = request_resource_conflict(&iomem_resource, res);
+ if (parent)
+ request_resource(parent, res);
+}
+
void __init efi_virtmap_init(void)
{
efi_memory_desc_t *md;
@@ -63,6 +97,8 @@ void __init efi_virtmap_init(void)
u64 paddr, npages, size;
pgprot_t prot;
+ if (!efi_mem_is_usable_region(md))
+ efi_register_mem_resource(md);
if (!(md->attribute & EFI_MEMORY_RUNTIME))
continue;
if (WARN(md->virt_addr == 0,
--
1.8.3.2
--
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