EFI regions are currently mapped in two separate places. The bulk of
the work is done in efi_map_regions() but when CONFIG_EFI_MIXED is
enabled the additional regions that are required when operating in
mixed mode are mapping in efi_setup_page_tables().
Pull everything into efi_map_regions() and refactor the test for
which regions should be mapped into a should_map_region() function.
Generously sprinkle comments to clarify the different cases.
Acked-by: Borislav Petkov <bp@xxxxxxx>
Tested-by: Dave Young <dyoung@xxxxxxxxxx> [kexec/kdump]
Tested-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx> [arm]
Acked-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
Signed-off-by: Matt Fleming <matt@xxxxxxxxxxxxxxxxxxx>
---
arch/x86/platform/efi/efi.c | 50 ++++++++++++++++++++++++++++++++++++------
arch/x86/platform/efi/efi_64.c | 20 -----------------
2 files changed, 43 insertions(+), 27 deletions(-)
diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c
index 1fbb408e2e72..625ec729b4e8 100644
--- a/arch/x86/platform/efi/efi.c
+++ b/arch/x86/platform/efi/efi.c
@@ -745,6 +745,46 @@ static void *efi_map_next_entry(void *entry)
return entry;
}
+static bool should_map_region(efi_memory_desc_t *md)
+{
+ /*
+ * Runtime regions always require runtime mappings (obviously).
+ */
+ if (md->attribute & EFI_MEMORY_RUNTIME)
+ return true;
+
+ /*
+ * 32-bit EFI doesn't suffer from the bug that requires us to
+ * reserve boot services regions, and mixed mode support
+ * doesn't exist for 32-bit kernels.
+ */
+ if (IS_ENABLED(CONFIG_X86_32))
+ return false;
+
+ /*
+ * Map all of RAM so that we can access arguments in the 1:1
+ * mapping when making EFI runtime calls.
+ */
+ if (IS_ENABLED(CONFIG_EFI_MIXED) && !efi_is_native()) {
+ if (md->type == EFI_CONVENTIONAL_MEMORY ||
+ md->type == EFI_LOADER_DATA ||
+ md->type == EFI_LOADER_CODE)
+ return true;
+ }
+
+ /*
+ * Map boot services regions as a workaround for buggy
+ * firmware that accesses them even when they shouldn't.
+ *
+ * See efi_{reserve,free}_boot_services().
+ */
+ if (md->type == EFI_BOOT_SERVICES_CODE ||
+ md->type == EFI_BOOT_SERVICES_DATA)
+ return true;
+
+ return false;
+}
+
/*
* Map the efi memory ranges of the runtime services and update new_mmap with
* virtual addresses.
@@ -761,13 +801,9 @@ static void * __init efi_map_regions(int *count, int *pg_shift)
p = NULL;
while ((p = efi_map_next_entry(p))) {
md = p;
- if (!(md->attribute & EFI_MEMORY_RUNTIME)) {
-#ifdef CONFIG_X86_64
- if (md->type != EFI_BOOT_SERVICES_CODE &&
- md->type != EFI_BOOT_SERVICES_DATA)
-#endif
- continue;
- }
+
+ if (!should_map_region(md))
+ continue;
efi_map_region(md);
get_systab_virt_addr(md);
diff --git a/arch/x86/platform/efi/efi_64.c b/arch/x86/platform/efi/efi_64.c
index 677e29e29473..45434ea345e9 100644
--- a/arch/x86/platform/efi/efi_64.c
+++ b/arch/x86/platform/efi/efi_64.c
@@ -214,7 +214,6 @@ void efi_sync_low_kernel_mappings(void)
int __init efi_setup_page_tables(unsigned long pa_memmap, unsigned num_pages)
{
unsigned long pfn, text;
- efi_memory_desc_t *md;
struct page *page;
unsigned npages;
pgd_t *pgd;
@@ -248,25 +247,6 @@ int __init efi_setup_page_tables(unsigned long pa_memmap, unsigned num_pages)
if (!IS_ENABLED(CONFIG_EFI_MIXED))
return 0;
- /*
- * Map all of RAM so that we can access arguments in the 1:1
- * mapping when making EFI runtime calls.
- */
- for_each_efi_memory_desc(md) {
- if (md->type != EFI_CONVENTIONAL_MEMORY &&
- md->type != EFI_LOADER_DATA &&
- md->type != EFI_LOADER_CODE)
- continue;
-
- pfn = md->phys_addr >> PAGE_SHIFT;
- npages = md->num_pages;
-
- if (kernel_map_pages_in_pgd(pgd, pfn, md->phys_addr, npages, _PAGE_RW)) {
- pr_err("Failed to map 1:1 memory\n");
- return 1;
- }
- }
-
page = alloc_page(GFP_KERNEL|__GFP_DMA32);
if (!page)
panic("Unable to allocate EFI runtime stack < 4GB\n");
--
2.9.3
--
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