From: Ard Biesheuvel <ardb@google.com>
To: linux-efi@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, Ard Biesheuvel <ardb@kernel.org>,
Evgeniy Baskov <baskov@ispras.ru>, Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
Ingo Molnar <mingo@redhat.com>,
Thomas Gleixner <tglx@linutronix.de>,
Peter Jones <pjones@redhat.com>,
Matthew Garrett <mjg59@srcf.ucam.org>,
Gerd Hoffmann <kraxel@redhat.com>,
Kees Cook <keescook@chromium.org>,
"H. Peter Anvin" <hpa@zytor.com>
Subject: [PATCH v2 11/15] x86/boot: Derive file size from _edata symbol
Date: Tue, 12 Sep 2023 09:01:02 +0000 [thread overview]
Message-ID: <20230912090051.4014114-28-ardb@google.com> (raw)
In-Reply-To: <20230912090051.4014114-17-ardb@google.com>
From: Ard Biesheuvel <ardb@kernel.org>
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@kernel.org>
---
arch/x86/boot/Makefile | 2 +-
arch/x86/boot/compressed/vmlinux.lds.S | 3 ++
| 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 0e98bc503699..cc04917b1ac6 100644
--- a/arch/x86/boot/Makefile
+++ b/arch/x86/boot/Makefile
@@ -89,7 +89,7 @@ $(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 4ff6ab1b67d9..5326f3b44194 100644
--- a/arch/x86/boot/compressed/vmlinux.lds.S
+++ b/arch/x86/boot/compressed/vmlinux.lds.S
@@ -47,6 +47,9 @@ SECTIONS
_data = . ;
*(.data)
*(.data.*)
+
+ /* add 4 bytes of extra space for a CRC-32 checksum */
+ . = ALIGN(. + 4, 0x20);
_edata = . ;
}
. = ALIGN(L1_CACHE_BYTES);
--git a/arch/x86/boot/header.S b/arch/x86/boot/header.S
index 06bd72a324c1..34e9b35b827c 100644
--- a/arch/x86/boot/header.S
+++ b/arch/x86/boot/header.S
@@ -233,7 +233,7 @@ 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)
--
2.42.0.283.g2d96d420d3-goog
next prev parent reply other threads:[~2023-09-12 9:02 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-09-12 9:00 [PATCH v2 00/15] x86/boot: Rework PE header generation Ard Biesheuvel
2023-09-12 9:00 ` [PATCH v2 01/15] x86/efi: Drop EFI stub .bss from .data section Ard Biesheuvel
2023-09-12 9:00 ` [PATCH v2 02/15] x86/efi: Disregard setup header of loaded image Ard Biesheuvel
2023-09-12 9:00 ` [PATCH v2 03/15] x86/efi: Drop alignment flags from PE section headers Ard Biesheuvel
2023-09-12 9:00 ` [PATCH v2 04/15] x86/boot: Remove the 'bugger off' message Ard Biesheuvel
2023-09-12 9:00 ` [PATCH v2 05/15] x86/boot: Omit compression buffer from PE/COFF image memory footprint Ard Biesheuvel
2023-09-12 9:00 ` [PATCH v2 06/15] x86/boot: Drop redundant code setting the root device Ard Biesheuvel
2023-09-12 9:00 ` [PATCH v2 07/15] x86/boot: Grab kernel_info offset from zoffset header directly Ard Biesheuvel
2023-09-12 9:00 ` [PATCH v2 08/15] x86/boot: Drop references to startup_64 Ard Biesheuvel
2023-09-15 9:15 ` Ingo Molnar
2023-09-15 13:48 ` Ard Biesheuvel
2023-09-15 15:40 ` Ingo Molnar
2023-09-15 15:45 ` Ingo Molnar
2023-09-15 15:48 ` Ard Biesheuvel
2023-09-12 9:01 ` [PATCH v2 09/15] x86/boot: Set EFI handover offset directly in header asm Ard Biesheuvel
2023-09-12 9:01 ` [PATCH v2 10/15] x86/boot: Define setup size in linker script Ard Biesheuvel
2023-09-12 9:01 ` Ard Biesheuvel [this message]
2023-09-12 9:01 ` [PATCH v2 12/15] x86/boot: Construct PE/COFF .text section from assembler Ard Biesheuvel
2023-09-12 9:01 ` [PATCH v2 13/15] x86/boot: Drop PE/COFF .reloc section Ard Biesheuvel
2023-09-12 9:01 ` [PATCH v2 14/15] x86/boot: Split off PE/COFF .data section Ard Biesheuvel
2023-09-12 9:01 ` [PATCH v2 15/15] x86/boot: Increase section and file alignment to 4k/512 Ard Biesheuvel
2023-09-15 9:22 ` [PATCH v2 00/15] x86/boot: Rework PE header generation Ingo Molnar
2023-09-15 11:30 ` Ingo Molnar
2023-09-15 13:21 ` Ard Biesheuvel
2023-09-15 13:28 ` Ard Biesheuvel
2023-09-16 9:10 ` Ingo Molnar
2023-09-16 19:14 ` Ard Biesheuvel
2023-09-17 17:50 ` Ingo Molnar
2023-10-03 2:02 ` Jan Hendrik Farr
2023-10-23 11:22 ` Ard Biesheuvel
2023-10-23 17:35 ` Jan Hendrik Farr
2023-10-24 8:21 ` Dave Young
2023-10-24 8:31 ` Dave Young
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20230912090051.4014114-28-ardb@google.com \
--to=ardb@google.com \
--cc=ardb@kernel.org \
--cc=baskov@ispras.ru \
--cc=bp@alien8.de \
--cc=dave.hansen@linux.intel.com \
--cc=hpa@zytor.com \
--cc=keescook@chromium.org \
--cc=kraxel@redhat.com \
--cc=linux-efi@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@redhat.com \
--cc=mjg59@srcf.ucam.org \
--cc=pjones@redhat.com \
--cc=tglx@linutronix.de \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).