Merge tag 'x86-boot-2023-10-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 boot updates from Ingo Molnar:

 - Rework PE header generation, primarily to generate a modern, 4k
   aligned kernel image view with narrower W^X permissions.

 - Further refine init-lifetime annotations

 - Misc cleanups & fixes

* tag 'x86-boot-2023-10-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (23 commits)
  x86/boot: efistub: Assign global boot_params variable
  x86/boot: Rename conflicting 'boot_params' pointer to 'boot_params_ptr'
  x86/head/64: Move the __head definition to <asm/init.h>
  x86/head/64: Add missing __head annotation to startup_64_load_idt()
  x86/head/64: Mark 'startup_gdt[]' and 'startup_gdt_descr' as __initdata
  x86/boot: Harmonize the style of array-type parameter for fixup_pointer() calls
  x86/boot: Fix incorrect startup_gdt_descr.size
  x86/boot: Compile boot code with -std=gnu11 too
  x86/boot: Increase section and file alignment to 4k/512
  x86/boot: Split off PE/COFF .data section
  x86/boot: Drop PE/COFF .reloc section
  x86/boot: Construct PE/COFF .text section from assembler
  x86/boot: Derive file size from _edata symbol
  x86/boot: Define setup size in linker script
  x86/boot: Set EFI handover offset directly in header asm
  x86/boot: Grab kernel_info offset from zoffset header directly
  x86/boot: Drop references to startup_64
  x86/boot: Drop redundant code setting the root device
  x86/boot: Omit compression buffer from PE/COFF image memory footprint
  x86/boot: Remove the 'bugger off' message
  ...

3 files changed, 7 insertions, 50 deletions

diff --git a/drivers/firmware/efi/libstub/Makefile b/drivers/firmware/efi/libstub/Makefile
index a1157c2a7170..ef4c12f0877b 100644
--- a/drivers/firmware/efi/libstub/Makefile
+++ b/drivers/firmware/efi/libstub/Makefile
@@ -108,13 +108,6 @@ lib-y				:= $(patsubst %.o,%.stub.o,$(lib-y))
 # https://bugs.llvm.org/show_bug.cgi?id=46480
 STUBCOPY_FLAGS-y		+= --remove-section=.note.gnu.property
 
-#
-# For x86, bootloaders like systemd-boot or grub-efi do not zero-initialize the
-# .bss section, so the .bss section of the EFI stub needs to be included in the
-# .data section of the compressed kernel to ensure initialization. Rename the
-# .bss section here so it's easy to pick out in the linker script.
-#
-STUBCOPY_FLAGS-$(CONFIG_X86)	+= --rename-section .bss=.bss.efistub,load,alloc
 STUBCOPY_RELOC-$(CONFIG_X86_32)	:= R_386_32
 STUBCOPY_RELOC-$(CONFIG_X86_64)	:= R_X86_64_64
 
diff --git a/drivers/firmware/efi/libstub/x86-stub.c b/drivers/firmware/efi/libstub/x86-stub.c
index 9d5df683f882..1bfdae34df39 100644
--- a/drivers/firmware/efi/libstub/x86-stub.c
+++ b/drivers/firmware/efi/libstub/x86-stub.c
@@ -449,9 +449,8 @@ void __noreturn efi_stub_entry(efi_handle_t handle,
 efi_status_t __efiapi efi_pe_entry(efi_handle_t handle,
 				   efi_system_table_t *sys_table_arg)
 {
-	struct boot_params *boot_params;
-	struct setup_header *hdr;
-	void *image_base;
+	static struct boot_params boot_params __page_aligned_bss;
+	struct setup_header *hdr = &boot_params.hdr;
 	efi_guid_t proto = LOADED_IMAGE_PROTOCOL_GUID;
 	int options_size = 0;
 	efi_status_t status;
@@ -469,30 +468,9 @@ efi_status_t __efiapi efi_pe_entry(efi_handle_t handle,
 		efi_exit(handle, status);
 	}
 
-	image_base = efi_table_attr(image, image_base);
-
-	status = efi_allocate_pages(sizeof(struct boot_params),
-				    (unsigned long *)&boot_params, ULONG_MAX);
-	if (status != EFI_SUCCESS) {
-		efi_err("Failed to allocate lowmem for boot params\n");
-		efi_exit(handle, status);
-	}
-
-	memset(boot_params, 0x0, sizeof(struct boot_params));
-
-	hdr = &boot_params->hdr;
-
-	/* Copy the setup header from the second sector to boot_params */
-	memcpy(&hdr->jump, image_base + 512,
-	       sizeof(struct setup_header) - offsetof(struct setup_header, jump));
-
-	/*
-	 * Fill out some of the header fields ourselves because the
-	 * EFI firmware loader doesn't load the first sector.
-	 */
+	/* Assign the setup_header fields that the kernel actually cares about */
 	hdr->root_flags	= 1;
 	hdr->vid_mode	= 0xffff;
-	hdr->boot_flag	= 0xAA55;
 
 	hdr->type_of_loader = 0x21;
 
@@ -501,25 +479,13 @@ efi_status_t __efiapi efi_pe_entry(efi_handle_t handle,
 	if (!cmdline_ptr)
 		goto fail;
 
-	efi_set_u64_split((unsigned long)cmdline_ptr,
-			  &hdr->cmd_line_ptr, &boot_params->ext_cmd_line_ptr);
-
-	hdr->ramdisk_image = 0;
-	hdr->ramdisk_size = 0;
-
-	/*
-	 * Disregard any setup data that was provided by the bootloader:
-	 * setup_data could be pointing anywhere, and we have no way of
-	 * authenticating or validating the payload.
-	 */
-	hdr->setup_data = 0;
+	efi_set_u64_split((unsigned long)cmdline_ptr, &hdr->cmd_line_ptr,
+			  &boot_params.ext_cmd_line_ptr);
 
-	efi_stub_entry(handle, sys_table_arg, boot_params);
+	efi_stub_entry(handle, sys_table_arg, &boot_params);
 	/* not reached */
 
 fail:
-	efi_free(sizeof(struct boot_params), (unsigned long)boot_params);
-
 	efi_exit(handle, status);
 }
 
@@ -849,7 +815,7 @@ void __noreturn efi_stub_entry(efi_handle_t handle,
 	unsigned long kernel_entry;
 	efi_status_t status;
 
-	boot_params_pointer = boot_params;
+	boot_params_ptr = boot_params;
 
 	efi_system_table = sys_table_arg;
 	/* Check if we were booted by the EFI firmware */
diff --git a/drivers/firmware/efi/libstub/x86-stub.h b/drivers/firmware/efi/libstub/x86-stub.h
index 2748bca192df..37c5a36b9d8c 100644
--- a/drivers/firmware/efi/libstub/x86-stub.h
+++ b/drivers/firmware/efi/libstub/x86-stub.h
@@ -2,8 +2,6 @@
 
 #include <linux/efi.h>
 
-extern struct boot_params *boot_params_pointer asm("boot_params");
-
 extern void trampoline_32bit_src(void *, bool);
 extern const u16 trampoline_ljmp_imm_offset;