From: Ard Biesheuvel <ardb@xxxxxxxxxx> [ Commit aeb92067f6ae994b541d7f9752fe54ed3d108bcc upstream ] Tweak the linker script so that the value of _edata represents the decompressor binary's file size rounded up to the appropriate alignment. This removes the need to calculate it in the build tool, and will make it easier to refer to the file size from the header directly in subsequent changes to the PE header layout. While adding _edata to the sed regex that parses the compressed vmlinux's symbol list, tweak the regex a bit for conciseness. This change has no impact on the resulting bzImage binary when configured with CONFIG_EFI_STUB=y. Signed-off-by: Ard Biesheuvel <ardb@xxxxxxxxxx> Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx> Link: https://lore.kernel.org/r/20230915171623.655440-14-ardb@xxxxxxxxxx Signed-off-by: Ard Biesheuvel <ardb@xxxxxxxxxx> --- arch/x86/boot/Makefile | 2 +- arch/x86/boot/compressed/vmlinux.lds.S | 3 ++ arch/x86/boot/header.S | 2 +- arch/x86/boot/tools/build.c | 30 +++++--------------- 4 files changed, 12 insertions(+), 25 deletions(-) diff --git a/arch/x86/boot/Makefile b/arch/x86/boot/Makefile index 10ea28469788..b92e00836f69 100644 --- a/arch/x86/boot/Makefile +++ b/arch/x86/boot/Makefile @@ -91,7 +91,7 @@ $(obj)/vmlinux.bin: $(obj)/compressed/vmlinux FORCE SETUP_OBJS = $(addprefix $(obj)/,$(setup-y)) -sed-zoffset := -e 's/^\([0-9a-fA-F]*\) [a-zA-Z] \(startup_32\|efi32_stub_entry\|efi64_stub_entry\|efi_pe_entry\|efi32_pe_entry\|input_data\|kernel_info\|_end\|_ehead\|_text\|z_.*\)$$/\#define ZO_\2 0x\1/p' +sed-zoffset := -e 's/^\([0-9a-fA-F]*\) [a-zA-Z] \(startup_32\|efi.._stub_entry\|efi\(32\)\?_pe_entry\|input_data\|kernel_info\|_end\|_ehead\|_text\|_edata\|z_.*\)$$/\#define ZO_\2 0x\1/p' quiet_cmd_zoffset = ZOFFSET $@ cmd_zoffset = $(NM) $< | sed -n $(sed-zoffset) > $@ diff --git a/arch/x86/boot/compressed/vmlinux.lds.S b/arch/x86/boot/compressed/vmlinux.lds.S index 32892e81bf61..aa7e9848cd8f 100644 --- a/arch/x86/boot/compressed/vmlinux.lds.S +++ b/arch/x86/boot/compressed/vmlinux.lds.S @@ -46,6 +46,9 @@ SECTIONS _data = . ; *(.data) *(.data.*) + + /* Add 4 bytes of extra space for a CRC-32 checksum */ + . = ALIGN(. + 4, 0x20); _edata = . ; } . = ALIGN(L1_CACHE_BYTES); diff --git a/arch/x86/boot/header.S b/arch/x86/boot/header.S index 6dddf469ca60..b43b55130855 100644 --- a/arch/x86/boot/header.S +++ b/arch/x86/boot/header.S @@ -232,7 +232,7 @@ sentinel: .byte 0xff, 0xff /* Used to detect broken loaders */ hdr: .byte setup_sects - 1 root_flags: .word ROOT_RDONLY -syssize: .long 0 /* Filled in by build.c */ +syssize: .long ZO__edata / 16 ram_size: .word 0 /* Obsolete */ vid_mode: .word SVGA_MODE root_dev: .word 0 /* Default to major/minor 0/0 */ diff --git a/arch/x86/boot/tools/build.c b/arch/x86/boot/tools/build.c index 745d64b6d930..e792c6c5a634 100644 --- a/arch/x86/boot/tools/build.c +++ b/arch/x86/boot/tools/build.c @@ -52,6 +52,7 @@ u8 buf[SETUP_SECT_MAX*512]; static unsigned long efi_pe_entry; static unsigned long efi32_pe_entry; +static unsigned long _edata; static unsigned long _end; /*----------------------------------------------------------------------*/ @@ -308,6 +309,7 @@ static void parse_zoffset(char *fname) while (p && *p) { PARSE_ZOFS(p, efi_pe_entry); PARSE_ZOFS(p, efi32_pe_entry); + PARSE_ZOFS(p, _edata); PARSE_ZOFS(p, _end); p = strchr(p, '\n'); @@ -320,7 +322,6 @@ int main(int argc, char ** argv) { unsigned int i, sz, setup_sectors; int c; - u32 sys_size; struct stat sb; FILE *file, *dest; int fd; @@ -368,24 +369,14 @@ int main(int argc, char ** argv) die("Unable to open `%s': %m", argv[2]); if (fstat(fd, &sb)) die("Unable to stat `%s': %m", argv[2]); - sz = sb.st_size; + if (_edata != sb.st_size) + die("Unexpected file size `%s': %u != %u", argv[2], _edata, + sb.st_size); + sz = _edata - 4; kernel = mmap(NULL, sz, PROT_READ, MAP_SHARED, fd, 0); if (kernel == MAP_FAILED) die("Unable to mmap '%s': %m", argv[2]); - /* Number of 16-byte paragraphs, including space for a 4-byte CRC */ - sys_size = (sz + 15 + 4) / 16; -#ifdef CONFIG_EFI_STUB - /* - * COFF requires minimum 32-byte alignment of sections, and - * adding a signature is problematic without that alignment. - */ - sys_size = (sys_size + 1) & ~1; -#endif - - /* Patch the setup code with the appropriate size parameters */ - put_unaligned_le32(sys_size, &buf[0x1f4]); - - update_pecoff_text(setup_sectors * 512, i + (sys_size * 16)); + update_pecoff_text(setup_sectors * 512, i + _edata); crc = partial_crc32(buf, i, crc); @@ -397,13 +388,6 @@ int main(int argc, char ** argv) if (fwrite(kernel, 1, sz, dest) != sz) die("Writing kernel failed"); - /* Add padding leaving 4 bytes for the checksum */ - while (sz++ < (sys_size*16) - 4) { - crc = partial_crc32_one('\0', crc); - if (fwrite("\0", 1, 1, dest) != 1) - die("Writing padding failed"); - } - /* Write the CRC */ put_unaligned_le32(crc, buf); if (fwrite(buf, 1, 4, dest) != 4) -- 2.44.0.769.g3c40516874-goog
