Some machines, such as the Lenovo ThinkPad W541 with firmware GNET80WW
(2.28), include memory map entries with phys_addr=0x0 and num_pages=0.
We shouldn't ever try to map these errors, so if we get as far as
efi_map_region(), show a traceback.
This additionally makes should_map_region() say not to map them, but I
fixed both places in case another caller of efi_map_region() ever arises
in the future.
Signed-off-by: Peter Jones <pjones@xxxxxxxxxx>
---
arch/x86/platform/efi/efi.c | 4 ++++
arch/x86/platform/efi/efi_64.c | 19 ++++++++++++++++---
2 files changed, 20 insertions(+), 3 deletions(-)
diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c
index 0263391..d9f7131 100644
--- a/arch/x86/platform/efi/efi.c
+++ b/arch/x86/platform/efi/efi.c
@@ -707,6 +707,10 @@ static bool should_map_region(efi_memory_desc_t *md)
if (IS_ENABLED(CONFIG_X86_32))
return false;
+ if (md->num_pages == 0 ||
+ md->num_pages >= (((u64)-1LL) >> EFI_PAGE_SHIFT))
+ return false;
+
/*
* Map all of RAM so that we can access arguments in the 1:1
* mapping when making EFI runtime calls.
diff --git a/arch/x86/platform/efi/efi_64.c b/arch/x86/platform/efi/efi_64.c
index 319148b..7ee5d97 100644
--- a/arch/x86/platform/efi/efi_64.c
+++ b/arch/x86/platform/efi/efi_64.c
@@ -313,11 +313,24 @@ static void __init __map_region(efi_memory_desc_t *md, u64 va)
void __init efi_map_region(efi_memory_desc_t *md)
{
- unsigned long size = md->num_pages << PAGE_SHIFT;
+ u64 size = md->num_pages << PAGE_SHIFT;
u64 pa = md->phys_addr;
- if (efi_enabled(EFI_OLD_MEMMAP))
- return old_map_region(md);
+ /*
+ * hah hah the system firmware is having a good one on us
+ */
+ if (md->num_pages == 0 ||
+ md->num_pages >= (((u64)-1LL) >> EFI_PAGE_SHIFT)) {
+ pr_err("memmap from %p to %p is unreasonable. Not mapping it.\n",
+ (void *)pa, (void *)(pa+size));
+ WARN_ON(1);
+ return;
+ }
+
+ if (efi_enabled(EFI_OLD_MEMMAP)) {
+ old_map_region(md);
+ return;
+ }
/*
* Make sure the 1:1 mappings are present as a catch-all for b0rked
--
2.9.3
--
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