diff options
Diffstat (limited to 'user/grub/0009-linux-mixed-mode.patch')
| -rw-r--r-- | user/grub/0009-linux-mixed-mode.patch | 79 |
1 files changed, 0 insertions, 79 deletions
diff --git a/user/grub/0009-linux-mixed-mode.patch b/user/grub/0009-linux-mixed-mode.patch deleted file mode 100644 index d3b2135f2..000000000 --- a/user/grub/0009-linux-mixed-mode.patch +++ /dev/null @@ -1,79 +0,0 @@ -From 1f5b180742ff2706bc3a696d115ddbc677ec75b9 Mon Sep 17 00:00:00 2001 -From: Ard Biesheuvel <ardb@kernel.org> -Date: Mon, 7 Aug 2023 14:21:51 +0200 -Subject: loader/efi/linux: Implement x86 mixed mode using legacy boot - -Recent mixed-mode Linux kernels, i.e., v4.0 or newer, can access EFI -runtime services at OS runtime even when the OS was not entered via the -EFI stub. This is because, instead of reverting back to the firmware's -segment selectors, GDTs and IDTs, the 64-bit kernel simply calls 32-bit -runtime services using compatibility mode, i.e., the same mode used for -32-bit user space, without taking down all interrupt handling, exception -handling, etc. - -This means that GRUB's legacy x86 boot mode is sufficient to make use of -this: 32-bit i686 builds of GRUB can already boot 64-bit kernels in EFI -enlightened mode, but without going via the EFI stub, and provide all -the metadata that the OS needs to map the EFI runtime regions and call -EFI runtime services successfully. - -It does mean that GRUB should not attempt to invoke the firmware's -LoadImage()/StartImage() methods on kernel builds that it knows cannot -be started natively. So, add a check for this in the native EFI boot -path and fall back to legacy x86 mode in such cases. - -Note that in the general case, booting non-native images of the same -native word size, e.g., x64 EFI apps on arm64 firmware, might be -supported by means of emulation. So, let's only disallow images that use -a non-native word size. This will also permit booting i686 kernels on -x86_64 builds, although without access to runtime services, as this is -not supported by Linux. - -This change on top of 2.12-rc1 is sufficient to boot ordinary Linux -mixed mode builds and get full access to the EFI runtime services. - -Cc: Daniel Kiper <daniel.kiper@oracle.com> -Cc: Steve McIntyre <steve@einval.com> -Cc: Julian Andres Klode <julian.klode@canonical.com> -Signed-off-by: Ard Biesheuvel <ardb@kernel.org> -Acked-by: Dimitri John Ledkov <dimitri.ledkov@canonical.com> -Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com> ---- - grub-core/loader/efi/linux.c | 3 +++ - include/grub/efi/pe32.h | 6 ++++++ - 2 files changed, 9 insertions(+) - -diff --git a/grub-core/loader/efi/linux.c b/grub-core/loader/efi/linux.c -index ab8fb35..bfbd95a 100644 ---- a/grub-core/loader/efi/linux.c -+++ b/grub-core/loader/efi/linux.c -@@ -117,6 +117,9 @@ grub_arch_efi_linux_load_image_header (grub_file_t file, - return grub_error (GRUB_ERR_FILE_READ_ERROR, "failed to read COFF image header"); - } - -+ if (lh->pe_image_header.optional_header.magic != GRUB_PE32_NATIVE_MAGIC) -+ return grub_error (GRUB_ERR_NOT_IMPLEMENTED_YET, "non-native image not supported"); -+ - /* - * Linux kernels built for any architecture are guaranteed to support the - * LoadFile2 based initrd loading protocol if the image version is >= 1. -diff --git a/include/grub/efi/pe32.h b/include/grub/efi/pe32.h -index 101859a..4e6e9d2 100644 ---- a/include/grub/efi/pe32.h -+++ b/include/grub/efi/pe32.h -@@ -267,6 +267,12 @@ struct grub_pe32_section_table - - #define GRUB_PE32_SIGNATURE_SIZE 4 - -+#if GRUB_TARGET_SIZEOF_VOID_P == 8 -+#define GRUB_PE32_NATIVE_MAGIC GRUB_PE32_PE64_MAGIC -+#else -+#define GRUB_PE32_NATIVE_MAGIC GRUB_PE32_PE32_MAGIC -+#endif -+ - struct grub_pe_image_header - { - /* This is always PE\0\0. */ --- -cgit v1.1 - |