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x86/efi: Consolidate region mapping logic

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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@suse.de>
Tested-by: Dave Young <dyoung@redhat.com> [kexec/kdump]
Tested-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> [arm]
Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
This commit is contained in:
Matt Fleming 2016-06-20 14:36:51 +01:00
parent 4971531af3
commit ab72a27da4
2 changed files with 43 additions and 27 deletions
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50
arch/x86/platform/efi/efi.c
View File

@ -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);

20
arch/x86/platform/efi/efi_64.c
View File

@ -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");