Commit-ID: 99a5603e2a1f146ac0c6414d8a3669aa749ccff8
Gitweb: http://git.kernel.org/tip/99a5603e2a1f146ac0c6414d8a3669aa749ccff8
Author: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
AuthorDate: Fri, 4 Jul 2014 17:25:09 +0200
Committer: Matt Fleming <matt.fleming@xxxxxxxxx>
CommitDate: Fri, 18 Jul 2014 21:24:04 +0100
efi/arm64: Handle missing virtual mapping for UEFI System Table
If we cannot resolve the virtual address of the UEFI System Table, its
physical offset must be missing from the virtual memory map, and there
is really no point in proceeding with installing the virtual memory map
and the runtime services dispatch table. So back out gracefully.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
Acked-by: Mark Salter <msalter@xxxxxxxxxx>
Acked-by: Catalin Marinas <catalin.marinas@xxxxxxx>
Signed-off-by: Matt Fleming <matt.fleming@xxxxxxxxx>
---
arch/arm64/kernel/efi.c | 28 ++++++++++++++++++++++++----
1 file changed, 24 insertions(+), 4 deletions(-)
diff --git a/arch/arm64/kernel/efi.c b/arch/arm64/kernel/efi.c
index 56c3327..e72f310 100644
--- a/arch/arm64/kernel/efi.c
+++ b/arch/arm64/kernel/efi.c
@@ -414,13 +414,24 @@ static int __init arm64_enter_virtual_mode(void)
for_each_efi_memory_desc(&memmap, md) {
if (!(md->attribute & EFI_MEMORY_RUNTIME))
continue;
- if (remap_region(md, &virt_md))
- ++count;
+ if (!remap_region(md, &virt_md))
+ goto err_unmap;
+ ++count;
}
efi.systab = (__force void *)efi_lookup_mapped_addr(efi_system_table);
- if (efi.systab)
- set_bit(EFI_SYSTEM_TABLES, &efi.flags);
+ if (!efi.systab) {
+ /*
+ * If we have no virtual mapping for the System Table at this
+ * point, the memory map doesn't cover the physical offset where
+ * it resides. This means the System Table will be inaccessible
+ * to Runtime Services themselves once the virtual mapping is
+ * installed.
+ */
+ pr_err("Failed to remap EFI System Table -- buggy firmware?\n");
+ goto err_unmap;
+ }
+ set_bit(EFI_SYSTEM_TABLES, &efi.flags);
local_irq_save(flags);
cpu_switch_mm(idmap_pg_dir, &init_mm);
@@ -453,5 +464,14 @@ static int __init arm64_enter_virtual_mode(void)
set_bit(EFI_RUNTIME_SERVICES, &efi.flags);
return 0;
+
+err_unmap:
+ /* unmap all mappings that succeeded: there are 'count' of those */
+ for (virt_md = virtmap; count--; virt_md += memmap.desc_size) {
+ md = virt_md;
+ iounmap((__force void __iomem *)md->virt_addr);
+ }
+ kfree(virtmap);
+ return -1;
}
early_initcall(arm64_enter_virtual_mode);
--
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