aboutsummaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorSai Praneeth Prakhya <[email protected]>2018-12-21 18:22:34 -0800
committerIngo Molnar <[email protected]>2018-12-22 20:58:30 +0100
commit1debf0958fa27b7c469dbf22754929ec59a7c0e7 (patch)
tree08165c04e2c5565c82b8b676f881f31acf79e2c1
parent80424b02d42bb22f8ff8839cb93a84ade53b39c0 (diff)
x86/efi: Don't unmap EFI boot services code/data regions for EFI_OLD_MEMMAP and EFI_MIXED_MODE
The following commit: d5052a7130a6 ("x86/efi: Unmap EFI boot services code/data regions from efi_pgd") forgets to take two EFI modes into consideration, namely EFI_OLD_MEMMAP and EFI_MIXED_MODE: - EFI_OLD_MEMMAP is a legacy way of mapping EFI regions into swapper_pg_dir using ioremap() and init_memory_mapping(). This feature can be enabled by passing "efi=old_map" as kernel command line argument. But, efi_unmap_pages() unmaps EFI boot services code/data regions *only* from efi_pgd and hence cannot be used for unmapping EFI boot services code/data regions from swapper_pg_dir. Introduce a temporary fix to not unmap EFI boot services code/data regions when EFI_OLD_MEMMAP is enabled while working on a real fix. - EFI_MIXED_MODE is another feature where a 64-bit kernel runs on a 64-bit platform crippled by a 32-bit firmware. To support EFI_MIXED_MODE, all RAM (i.e. namely EFI regions like EFI_CONVENTIONAL_MEMORY, EFI_LOADER_<CODE/DATA>, EFI_BOOT_SERVICES_<CODE/DATA> and EFI_RUNTIME_CODE/DATA regions) is mapped into efi_pgd all the time to facilitate EFI runtime calls access it's arguments in 1:1 mode. Hence, don't unmap EFI boot services code/data regions when booted in mixed mode. Signed-off-by: Sai Praneeth Prakhya <[email protected]> Acked-by: Ard Biesheuvel <[email protected]> Cc: Andy Lutomirski <[email protected]> Cc: Bhupesh Sharma <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: Dave Hansen <[email protected]> Cc: Dave Hansen <[email protected]> Cc: H. Peter Anvin <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Rik van Riel <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: [email protected] Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Ingo Molnar <[email protected]>
-rw-r--r--arch/x86/platform/efi/quirks.c16
1 files changed, 16 insertions, 0 deletions
diff --git a/arch/x86/platform/efi/quirks.c b/arch/x86/platform/efi/quirks.c
index 09e811b9da26..17456a1d3f04 100644
--- a/arch/x86/platform/efi/quirks.c
+++ b/arch/x86/platform/efi/quirks.c
@@ -380,6 +380,22 @@ static void __init efi_unmap_pages(efi_memory_desc_t *md)
u64 pa = md->phys_addr;
u64 va = md->virt_addr;
+ /*
+ * To Do: Remove this check after adding functionality to unmap EFI boot
+ * services code/data regions from direct mapping area because
+ * "efi=old_map" maps EFI regions in swapper_pg_dir.
+ */
+ if (efi_enabled(EFI_OLD_MEMMAP))
+ return;
+
+ /*
+ * EFI mixed mode has all RAM mapped to access arguments while making
+ * EFI runtime calls, hence don't unmap EFI boot services code/data
+ * regions.
+ */
+ if (!efi_is_native())
+ return;
+
if (kernel_unmap_pages_in_pgd(pgd, pa, md->num_pages))
pr_err("Failed to unmap 1:1 mapping for 0x%llx\n", pa);