blob: a1be48d291cadfdf27da8149cdd3e71cfb68b998 [file] [log] [blame]
From 79fb929775cc74ca5ff60dc95d31c70aa622fac4 Mon Sep 17 00:00:00 2001
From: Ard Biesheuvel <ardb@kernel.org>
Date: Fri, 3 Jan 2020 12:39:46 +0100
Subject: [PATCH] efi/x86: Don't panic or BUG() on non-critical error
conditions
commit e2d68a955e49d61fd0384f23e92058dc9b79be5e upstream.
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: Paul Gortmaker <paul.gortmaker@windriver.com>
diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c
index ac8b2d45a033..9b1b133c860a 100644
--- a/arch/x86/platform/efi/efi.c
+++ b/arch/x86/platform/efi/efi.c
@@ -931,16 +931,14 @@ static void __init __efi_enter_virtual_mode(void)
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);
@@ -954,8 +952,7 @@ static void __init __efi_enter_virtual_mode(void)
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)) {
@@ -963,12 +960,11 @@ static void __init __efi_enter_virtual_mode(void)
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();
@@ -988,9 +984,9 @@ static void __init __efi_enter_virtual_mode(void)
}
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;
}
efi_free_boot_services();
@@ -1019,6 +1015,10 @@ static void __init __efi_enter_virtual_mode(void)
/* 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 08ce8177c3af..52a1e5192fa8 100644
--- a/arch/x86/platform/efi/efi_64.c
+++ b/arch/x86/platform/efi/efi_64.c
@@ -392,11 +392,12 @@ int __init efi_setup_page_tables(unsigned long pa_memmap, unsigned num_pages)
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);
--
2.7.4