Commit 743628e8 authored by Jordan Justen's avatar Jordan Justen Committed by H. Peter Anvin
Browse files

x86, efi stub: Add .reloc section back into image 



Some UEFI firmware will not load a .efi with a .reloc section
with a size of 0.

Therefore, we create a .efi image with 4 main areas and 3 sections.
1. PE/COFF file header
2. .setup section (covers all setup code following the first sector)
3. .reloc section (contains 1 dummy reloc entry, created in build.c)
4. .text section (covers the remaining kernel image)

To make room for the new .setup section data, the header
bugger_off_msg had to be shortened.

Reported-by: default avatarHenrik Rydberg <rydberg@euromail.se>
Signed-off-by: default avatarJordan Justen <jordan.l.justen@intel.com>
Link: http://lkml.kernel.org/r/1339085121-12760-1-git-send-email-jordan.l.justen@intel.com


Tested-by: default avatarLee G Rosenbaum <lee.g.rosenbaum@intel.com>
Tested-by: default avatarHenrik Rydberg <rydberg@euromail.se>
Cc: Matt Fleming <matt.fleming@intel.com>
Signed-off-by: default avatarH. Peter Anvin <hpa@zytor.com>
parent f6175f5b

arch/x86/boot/header.S

+31 −11
Original line number Diff line number Diff line
@@ -94,8 +94,8 @@ bs_die: 


	.section ".bsdata", "a"

bugger_off_msg:

	.ascii	"Direct booting from floppy is no longer supported.\r\n"

	.ascii	"Please use a boot loader program instead.\r\n"

	.ascii	"Direct floppy boot is not supported. "

	.ascii	"Use a boot loader program instead.\r\n"

	.ascii	"\n"

	.ascii	"Remove disk and press any key to reboot ...\r\n"

	.byte	0
@@ -111,7 +111,7 @@ coff_header: 
#else

	.word	0x8664				# x86-64

#endif

	.word	2				# nr_sections

	.word	3				# nr_sections

	.long	0 				# TimeDateStamp

	.long	0				# PointerToSymbolTable

	.long	1				# NumberOfSymbols
@@ -158,8 +158,8 @@ extra_header_fields: 
#else

	.quad	0				# ImageBase

#endif

	.long	0x1000				# SectionAlignment

	.long	0x200				# FileAlignment

	.long	0x20				# SectionAlignment

	.long	0x20				# FileAlignment

	.word	0				# MajorOperatingSystemVersion

	.word	0				# MinorOperatingSystemVersion

	.word	0				# MajorImageVersion
@@ -200,8 +200,10 @@ extra_header_fields: 


	# Section table

section_table:

	.ascii	".text"

	.byte	0

	#

	# The offset & size fields are filled in by build.c.

	#

	.ascii	".setup"

	.byte	0

	.byte	0

	.long	0
@@ -217,9 +219,8 @@ section_table: 


	#

	# The EFI application loader requires a relocation section

	# because EFI applications must be relocatable. But since

	# we don't need the loader to fixup any relocs for us, we

	# just create an empty (zero-length) .reloc section header.

	# because EFI applications must be relocatable. The .reloc

	# offset & size fields are filled in by build.c.

	#

	.ascii	".reloc"

	.byte	0
@@ -233,6 +234,25 @@ section_table: 
	.word	0				# NumberOfRelocations

	.word	0				# NumberOfLineNumbers

	.long	0x42100040			# Characteristics (section flags)



	#

	# The offset & size fields are filled in by build.c.

	#

	.ascii	".text"

	.byte	0

	.byte	0

	.byte	0

	.long	0

	.long	0x0				# startup_{32,64}

	.long	0				# Size of initialized data

						# on disk

	.long	0x0				# startup_{32,64}

	.long	0				# PointerToRelocations

	.long	0				# PointerToLineNumbers

	.word	0				# NumberOfRelocations

	.word	0				# NumberOfLineNumbers

	.long	0x60500020			# Characteristics (section flags)



#endif /* CONFIG_EFI_STUB */



	# Kernel attributes; used by setup.  This is part 1 of the

arch/x86/boot/tools/build.c

+109 −63
Original line number Diff line number Diff line
@@ -50,6 +50,8 @@ typedef unsigned int u32; 
u8 buf[SETUP_SECT_MAX*512];

int is_big_kernel;



#define PECOFF_RELOC_RESERVE 0x20



/*----------------------------------------------------------------------*/



static const u32 crctab32[] = {
@@ -133,11 +135,103 @@ static void usage(void) 
	die("Usage: build setup system [> image]");

}



int main(int argc, char ** argv)

{

#ifdef CONFIG_EFI_STUB

	unsigned int file_sz, pe_header;



static void update_pecoff_section_header(char *section_name, u32 offset, u32 size)

{

	unsigned int pe_header;

	unsigned short num_sections;

	u8 *section;



	pe_header = get_unaligned_le32(&buf[0x3c]);

	num_sections = get_unaligned_le16(&buf[pe_header + 6]);



#ifdef CONFIG_X86_32

	section = &buf[pe_header + 0xa8];

#else

	section = &buf[pe_header + 0xb8];

#endif



	while (num_sections > 0) {

		if (strncmp((char*)section, section_name, 8) == 0) {

			/* section header size field */

			put_unaligned_le32(size, section + 0x8);



			/* section header vma field */

			put_unaligned_le32(offset, section + 0xc);



			/* section header 'size of initialised data' field */

			put_unaligned_le32(size, section + 0x10);



			/* section header 'file offset' field */

			put_unaligned_le32(offset, section + 0x14);



			break;

		}

		section += 0x28;

		num_sections--;

	}

}



static void update_pecoff_setup_and_reloc(unsigned int size)

{

	u32 setup_offset = 0x200;

	u32 reloc_offset = size - PECOFF_RELOC_RESERVE;

	u32 setup_size = reloc_offset - setup_offset;



	update_pecoff_section_header(".setup", setup_offset, setup_size);

	update_pecoff_section_header(".reloc", reloc_offset, PECOFF_RELOC_RESERVE);



	/*

	 * Modify .reloc section contents with a single entry. The

	 * relocation is applied to offset 10 of the relocation section.

	 */

	put_unaligned_le32(reloc_offset + 10, &buf[reloc_offset]);

	put_unaligned_le32(10, &buf[reloc_offset + 4]);

}



static void update_pecoff_text(unsigned int text_start, unsigned int file_sz)

{

	unsigned int pe_header;

	unsigned int text_sz = file_sz - text_start;



	pe_header = get_unaligned_le32(&buf[0x3c]);



	/* Size of image */

	put_unaligned_le32(file_sz, &buf[pe_header + 0x50]);



	/*

	 * Size of code: Subtract the size of the first sector (512 bytes)

	 * which includes the header.

	 */

	put_unaligned_le32(file_sz - 512, &buf[pe_header + 0x1c]);



#ifdef CONFIG_X86_32

	/*

	 * Address of entry point.

	 *

	 * The EFI stub entry point is +16 bytes from the start of

	 * the .text section.

	 */

	put_unaligned_le32(text_start + 16, &buf[pe_header + 0x28]);

#else

	/*

	 * Address of entry point. startup_32 is at the beginning and

	 * the 64-bit entry point (startup_64) is always 512 bytes

	 * after. The EFI stub entry point is 16 bytes after that, as

	 * the first instruction allows legacy loaders to jump over

	 * the EFI stub initialisation

	 */

	put_unaligned_le32(text_start + 528, &buf[pe_header + 0x28]);

#endif /* CONFIG_X86_32 */



	update_pecoff_section_header(".text", text_start, text_sz);

}



#endif /* CONFIG_EFI_STUB */



int main(int argc, char ** argv)

{

	unsigned int i, sz, setup_sectors;

	int c;

	u32 sys_size;
@@ -163,6 +257,12 @@ int main(int argc, char ** argv) 
		die("Boot block hasn't got boot flag (0xAA55)");

	fclose(file);



#ifdef CONFIG_EFI_STUB

	/* Reserve 0x20 bytes for .reloc section */

	memset(buf+c, 0, PECOFF_RELOC_RESERVE);

	c += PECOFF_RELOC_RESERVE;

#endif



	/* Pad unused space with zeros */

	setup_sectors = (c + 511) / 512;

	if (setup_sectors < SETUP_SECT_MIN)
@@ -170,6 +270,10 @@ int main(int argc, char ** argv) 
	i = setup_sectors*512;

	memset(buf+c, 0, i-c);



#ifdef CONFIG_EFI_STUB

	update_pecoff_setup_and_reloc(i);

#endif



	/* Set the default root device */

	put_unaligned_le16(DEFAULT_ROOT_DEV, &buf[508]);
@@ -194,66 +298,8 @@ int main(int argc, char ** argv) 
	put_unaligned_le32(sys_size, &buf[0x1f4]);



#ifdef CONFIG_EFI_STUB

	file_sz = sz + i + ((sys_size * 16) - sz);



	pe_header = get_unaligned_le32(&buf[0x3c]);



	/* Size of image */

	put_unaligned_le32(file_sz, &buf[pe_header + 0x50]);



	/*

	 * Subtract the size of the first section (512 bytes) which

	 * includes the header and .reloc section. The remaining size

	 * is that of the .text section.

	 */

	file_sz -= 512;



	/* Size of code */

	put_unaligned_le32(file_sz, &buf[pe_header + 0x1c]);



#ifdef CONFIG_X86_32

	/*

	 * Address of entry point.

	 *

	 * The EFI stub entry point is +16 bytes from the start of

	 * the .text section.

	 */

	put_unaligned_le32(i + 16, &buf[pe_header + 0x28]);



	/* .text size */

	put_unaligned_le32(file_sz, &buf[pe_header + 0xb0]);



	/* .text vma */

	put_unaligned_le32(0x200, &buf[pe_header + 0xb4]);



	/* .text size of initialised data */

	put_unaligned_le32(file_sz, &buf[pe_header + 0xb8]);



	/* .text file offset */

	put_unaligned_le32(0x200, &buf[pe_header + 0xbc]);

#else

	/*

	 * Address of entry point. startup_32 is at the beginning and

	 * the 64-bit entry point (startup_64) is always 512 bytes

	 * after. The EFI stub entry point is 16 bytes after that, as

	 * the first instruction allows legacy loaders to jump over

	 * the EFI stub initialisation

	 */

	put_unaligned_le32(i + 528, &buf[pe_header + 0x28]);



	/* .text size */

	put_unaligned_le32(file_sz, &buf[pe_header + 0xc0]);



	/* .text vma */

	put_unaligned_le32(0x200, &buf[pe_header + 0xc4]);



	/* .text size of initialised data */

	put_unaligned_le32(file_sz, &buf[pe_header + 0xc8]);



	/* .text file offset */

	put_unaligned_le32(0x200, &buf[pe_header + 0xcc]);

#endif /* CONFIG_X86_32 */

#endif /* CONFIG_EFI_STUB */

	update_pecoff_text(setup_sectors * 512, sz + i + ((sys_size * 16) - sz));

#endif



	crc = partial_crc32(buf, i, crc);

	if (fwrite(buf, 1, i, stdout) != i)

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