diff options
Diffstat (limited to 'user/grub/0008-efi-pure64.patch')
| -rw-r--r-- | user/grub/0008-efi-pure64.patch | 110 |
1 files changed, 0 insertions, 110 deletions
diff --git a/user/grub/0008-efi-pure64.patch b/user/grub/0008-efi-pure64.patch deleted file mode 100644 index e07323c63..000000000 --- a/user/grub/0008-efi-pure64.patch +++ /dev/null @@ -1,110 +0,0 @@ -From 67ae3981dc5113e5af3a0539174bcd7eab8f7722 Mon Sep 17 00:00:00 2001 -From: Ard Biesheuvel <ardb@kernel.org> -Date: Thu, 3 Aug 2023 15:24:09 +0200 -Subject: loader/i386/linux: Prefer entry in long mode when booting via EFI - -The x86_64 Linux kernel can be booted in 32-bit mode, in which case the -startup code creates a set of preliminary page tables that map the first -4 GiB of physical memory 1:1 and enables paging. This is a prerequisite -for 64-bit execution and can therefore only be implemented in 32-bit code. - -The x86_64 Linux kernel can also be booted in 64-bit mode directly: this -implies that paging is already enabled and it is the responsibility of -the bootloader to ensure that the active page tables cover the entire -loaded image, including its BSS space, the size of which is described in -the image's setup header. - -Given that the EFI spec mandates execution in long mode for x86_64 and -stipulates that all system memory is mapped 1:1, the Linux/x86 -requirements for 64-bit entry can be met trivially when booting on -x86_64 via EFI. So, enter via the 64-bit entry point in this case. - -This involves inspecting the xloadflags field in the setup header to -check whether the 64-bit entry point is supported. This field was -introduced in Linux version v3.8 (early 2013). - -This change ensures that all EFI firmware tables and other assets passed -by the firmware or bootloader in memory remain mapped and accessible -throughout the early startup code. - -Avoiding the drop out of long mode will also be needed to support -upcoming CPU designs that no longer implement 32-bit mode at all -(as recently announced by Intel [0]). - -[0] https://www.intel.com/content/www/us/en/developer/articles/technical/envisioning-future-simplified-architecture.html - -Cc: Daniel Kiper <daniel.kiper@oracle.com> -Cc: Julian Andres Klode <julian.klode@canonical.com> -Signed-off-by: Ard Biesheuvel <ardb@kernel.org> -Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com> ---- - grub-core/loader/i386/linux.c | 12 ++++++++++++ - include/grub/i386/linux.h | 15 +++++++++++++-- - 2 files changed, 25 insertions(+), 2 deletions(-) - -diff --git a/grub-core/loader/i386/linux.c b/grub-core/loader/i386/linux.c -index 997647a..977757f 100644 ---- a/grub-core/loader/i386/linux.c -+++ b/grub-core/loader/i386/linux.c -@@ -624,6 +624,18 @@ grub_linux_boot (void) - } - #endif - -+#if defined (__x86_64__) && defined (GRUB_MACHINE_EFI) -+ if (grub_le_to_cpu16 (ctx.params->version) >= 0x020c && -+ (linux_params.xloadflags & LINUX_X86_XLF_KERNEL_64) != 0) -+ { -+ struct grub_relocator64_efi_state state64; -+ -+ state64.rsi = ctx.real_mode_target; -+ state64.rip = ctx.params->code32_start + LINUX_X86_STARTUP64_OFFSET; -+ return grub_relocator64_efi_boot (relocator, state64); -+ } -+#endif -+ - /* FIXME. */ - /* asm volatile ("lidt %0" : : "m" (idt_desc)); */ - state.ebp = state.edi = state.ebx = 0; -diff --git a/include/grub/i386/linux.h b/include/grub/i386/linux.h -index 0fd6e12..d4b5508 100644 ---- a/include/grub/i386/linux.h -+++ b/include/grub/i386/linux.h -@@ -69,6 +69,16 @@ - #define GRUB_LINUX_OFW_SIGNATURE \ - (' ' << 24 | 'W' << 16 | 'F' << 8 | 'O') - -+#define LINUX_X86_XLF_KERNEL_64 (1<<0) -+#define LINUX_X86_XLF_CAN_BE_LOADED_ABOVE_4G (1<<1) -+#define LINUX_X86_XLF_EFI_HANDOVER_32 (1<<2) -+#define LINUX_X86_XLF_EFI_HANDOVER_64 (1<<3) -+#define LINUX_X86_XLF_EFI_KEXEC (1<<4) -+#define LINUX_X86_XLF_5LEVEL (1<<5) -+#define LINUX_X86_XLF_5LEVEL_ENABLED (1<<6) -+ -+#define LINUX_X86_STARTUP64_OFFSET 0x200 -+ - #ifndef ASM_FILE - - #define GRUB_E820_RAM 1 -@@ -138,7 +148,7 @@ struct linux_i386_kernel_header - grub_uint32_t kernel_alignment; - grub_uint8_t relocatable; - grub_uint8_t min_alignment; -- grub_uint8_t pad[2]; -+ grub_uint16_t xloadflags; - grub_uint32_t cmdline_size; - grub_uint32_t hardware_subarch; - grub_uint64_t hardware_subarch_data; -@@ -315,7 +325,8 @@ struct linux_kernel_params - grub_uint32_t initrd_addr_max; /* Maximum initrd address */ - grub_uint32_t kernel_alignment; /* Alignment of the kernel */ - grub_uint8_t relocatable_kernel; /* Is the kernel relocatable */ -- grub_uint8_t pad1[3]; -+ grub_uint8_t min_alignment; -+ grub_uint16_t xloadflags; - grub_uint32_t cmdline_size; /* Size of the kernel command line */ - grub_uint32_t hardware_subarch; - grub_uint64_t hardware_subarch_data; --- -cgit v1.1 - |