user/grub: Update to 2.12_rc1

Fixes: #1065, #1066, #1073

1 files changed, 110 insertions, 0 deletions

diff --git a/user/grub/0008-efi-pure64.patch b/user/grub/0008-efi-pure64.patch
new file mode 100644
index 000000000..e07323c63
--- /dev/null
+++ b/user/grub/0008-efi-pure64.patch
@@ -0,0 +1,110 @@
+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
+