Commit-ID: b61a76f8850d2979550abc42d7e09154ebb8d785
Gitweb: http://git.kernel.org/tip/b61a76f8850d2979550abc42d7e09154ebb8d785
Author: Matt Fleming <matt@xxxxxxxxxxxxxxxxxxx>
AuthorDate: Fri, 27 Nov 2015 21:09:32 +0000
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Sun, 29 Nov 2015 09:15:42 +0100
x86/efi: Map RAM into the identity page table for mixed mode
We are relying on the pre-existing mappings in 'trampoline_pgd'
when accessing function arguments in the EFI mixed mode thunking
code.
Instead let's map memory explicitly so that things will continue
to work when we move to a separate page table in the future.
Signed-off-by: Matt Fleming <matt@xxxxxxxxxxxxxxxxxxx>
Reviewed-by: Borislav Petkov <bp@xxxxxxx>
Acked-by: Borislav Petkov <bp@xxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxxxxxx>
Cc: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Brian Gerst <brgerst@xxxxxxxxx>
Cc: Denys Vlasenko <dvlasenk@xxxxxxxxxx>
Cc: H. Peter Anvin <hpa@xxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Sai Praneeth Prakhya <sai.praneeth.prakhya@xxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Toshi Kani <toshi.kani@xxxxxx>
Cc: linux-efi@xxxxxxxxxxxxxxx
Link: http://lkml.kernel.org/r/1448658575-17029-4-git-send-email-matt@xxxxxxxxxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
arch/x86/platform/efi/efi_64.c | 20 ++++++++++++++++++++
1 file changed, 20 insertions(+)
diff --git a/arch/x86/platform/efi/efi_64.c b/arch/x86/platform/efi/efi_64.c
index 5aa186d..102976d 100644
--- a/arch/x86/platform/efi/efi_64.c
+++ b/arch/x86/platform/efi/efi_64.c
@@ -144,6 +144,7 @@ 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;
@@ -177,6 +178,25 @@ 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(&memmap, 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, 0)) {
+ 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");
--
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