efi/x86: Don't panic or BUG() on non-critical error conditions
[ Upstream commit e2d68a955e49d61fd0384f23e92058dc9b79be5e ]
The logic in __efi_enter_virtual_mode() does a number of steps in
sequence, all of which may fail in one way or the other. In most
cases, we simply print an error and disable EFI runtime services
support, but in some cases, we BUG() or panic() and bring down the
system when encountering conditions that we could easily handle in
the same way.
While at it, replace a pointless page-to-virt-phys conversion with
one that goes straight from struct page to physical.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Arvind Sankar <nivedita@alum.mit.edu>
Cc: Matthew Garrett <mjg59@google.com>
Cc: linux-efi@vger.kernel.org
Link: https://lkml.kernel.org/r/20200103113953.9571-14-ardb@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c
index 5b02753..e7f19de 100644
--- a/arch/x86/platform/efi/efi.c
+++ b/arch/x86/platform/efi/efi.c
@@ -930,16 +930,14 @@
if (efi_alloc_page_tables()) {
pr_err("Failed to allocate EFI page tables\n");
- clear_bit(EFI_RUNTIME_SERVICES, &efi.flags);
- return;
+ goto err;
}
efi_merge_regions();
new_memmap = efi_map_regions(&count, &pg_shift);
if (!new_memmap) {
pr_err("Error reallocating memory, EFI runtime non-functional!\n");
- clear_bit(EFI_RUNTIME_SERVICES, &efi.flags);
- return;
+ goto err;
}
pa = __pa(new_memmap);
@@ -953,8 +951,7 @@
if (efi_memmap_init_late(pa, efi.memmap.desc_size * count)) {
pr_err("Failed to remap late EFI memory map\n");
- clear_bit(EFI_RUNTIME_SERVICES, &efi.flags);
- return;
+ goto err;
}
if (efi_enabled(EFI_DBG)) {
@@ -962,12 +959,11 @@
efi_print_memmap();
}
- BUG_ON(!efi.systab);
+ if (WARN_ON(!efi.systab))
+ goto err;
- if (efi_setup_page_tables(pa, 1 << pg_shift)) {
- clear_bit(EFI_RUNTIME_SERVICES, &efi.flags);
- return;
- }
+ if (efi_setup_page_tables(pa, 1 << pg_shift))
+ goto err;
efi_sync_low_kernel_mappings();
@@ -987,9 +983,9 @@
}
if (status != EFI_SUCCESS) {
- pr_alert("Unable to switch EFI into virtual mode (status=%lx)!\n",
- status);
- panic("EFI call to SetVirtualAddressMap() failed!");
+ pr_err("Unable to switch EFI into virtual mode (status=%lx)!\n",
+ status);
+ goto err;
}
/*
@@ -1016,6 +1012,10 @@
/* clean DUMMY object */
efi_delete_dummy_variable();
+ return;
+
+err:
+ clear_bit(EFI_RUNTIME_SERVICES, &efi.flags);
}
void __init efi_enter_virtual_mode(void)
diff --git a/arch/x86/platform/efi/efi_64.c b/arch/x86/platform/efi/efi_64.c
index ae369c2..0ebb7f9 100644
--- a/arch/x86/platform/efi/efi_64.c
+++ b/arch/x86/platform/efi/efi_64.c
@@ -390,11 +390,12 @@
return 0;
page = alloc_page(GFP_KERNEL|__GFP_DMA32);
- if (!page)
- panic("Unable to allocate EFI runtime stack < 4GB\n");
+ if (!page) {
+ pr_err("Unable to allocate EFI runtime stack < 4GB\n");
+ return 1;
+ }
- efi_scratch.phys_stack = virt_to_phys(page_address(page));
- efi_scratch.phys_stack += PAGE_SIZE; /* stack grows down */
+ efi_scratch.phys_stack = page_to_phys(page + 1); /* stack grows down */
npages = (_etext - _text) >> PAGE_SHIFT;
text = __pa(_text);