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-rw-r--r--arch/ia64/kernel/efi.c46
1 files changed, 43 insertions, 3 deletions
diff --git a/arch/ia64/kernel/efi.c b/arch/ia64/kernel/efi.c
index f45f91d38ca..78d29b79947 100644
--- a/arch/ia64/kernel/efi.c
+++ b/arch/ia64/kernel/efi.c
@@ -660,6 +660,29 @@ efi_memory_descriptor (unsigned long phys_addr)
return NULL;
}
+static int
+efi_memmap_intersects (unsigned long phys_addr, unsigned long size)
+{
+ void *efi_map_start, *efi_map_end, *p;
+ efi_memory_desc_t *md;
+ u64 efi_desc_size;
+ unsigned long end;
+
+ efi_map_start = __va(ia64_boot_param->efi_memmap);
+ efi_map_end = efi_map_start + ia64_boot_param->efi_memmap_size;
+ efi_desc_size = ia64_boot_param->efi_memdesc_size;
+
+ end = phys_addr + size;
+
+ for (p = efi_map_start; p < efi_map_end; p += efi_desc_size) {
+ md = p;
+
+ if (md->phys_addr < end && efi_md_end(md) > phys_addr)
+ return 1;
+ }
+ return 0;
+}
+
u32
efi_mem_type (unsigned long phys_addr)
{
@@ -766,11 +789,28 @@ valid_phys_addr_range (unsigned long phys_addr, unsigned long size)
int
valid_mmap_phys_addr_range (unsigned long pfn, unsigned long size)
{
+ unsigned long phys_addr = pfn << PAGE_SHIFT;
+ u64 attr;
+
+ attr = efi_mem_attribute(phys_addr, size);
+
/*
- * MMIO regions are often missing from the EFI memory map.
- * We must allow mmap of them for programs like X, so we
- * currently can't do any useful validation.
+ * /dev/mem mmap uses normal user pages, so we don't need the entire
+ * granule, but the entire region we're mapping must support the same
+ * attribute.
*/
+ if (attr & EFI_MEMORY_WB || attr & EFI_MEMORY_UC)
+ return 1;
+
+ /*
+ * Intel firmware doesn't tell us about all the MMIO regions, so
+ * in general we have to allow mmap requests. But if EFI *does*
+ * tell us about anything inside this region, we should deny it.
+ * The user can always map a smaller region to avoid the overlap.
+ */
+ if (efi_memmap_intersects(phys_addr, size))
+ return 0;
+
return 1;
}