From 743628e868c5992354fc80b4d1e9a6143da1c0e6 Mon Sep 17 00:00:00 2001 From: Jordan Justen Date: Thu, 7 Jun 2012 09:05:21 -0700 Subject: [PATCH] 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: Henrik Rydberg Signed-off-by: Jordan Justen Link: http://lkml.kernel.org/r/1339085121-12760-1-git-send-email-jordan.l.justen@intel.com Tested-by: Lee G Rosenbaum Tested-by: Henrik Rydberg Cc: Matt Fleming Signed-off-by: H. Peter Anvin --- arch/x86/boot/header.S | 42 ++++++++--- arch/x86/boot/tools/build.c | 172 ++++++++++++++++++++++++++++---------------- 2 files changed, 140 insertions(+), 74 deletions(-) diff --git a/arch/x86/boot/header.S b/arch/x86/boot/header.S index 8bbea6a..efe5acf 100644 --- a/arch/x86/boot/header.S +++ b/arch/x86/boot/header.S @@ -94,10 +94,10 @@ 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" + .ascii "Remove disk and press any key to reboot ...\r\n" .byte 0 #ifdef CONFIG_EFI_STUB @@ -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 diff --git a/arch/x86/boot/tools/build.c b/arch/x86/boot/tools/build.c index 3f61f6e..4b8e165 100644 --- a/arch/x86/boot/tools/build.c +++ b/arch/x86/boot/tools/build.c @@ -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) -- 2.7.4