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x86/boot: Drop PE/COFF .reloc section

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commit fa5750521e0a4efbc1af05223da9c4bbd6c21c83 upstream.

Ancient buggy EFI loaders may have required a .reloc section to be
present at some point in time, but this has not been true for a long
time so the .reloc section can just be dropped.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20230915171623.655440-16-ardb@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Ard Biesheuvel 2023-09-15 17:16:30 +00:00 committed by Greg Kroah-Hartman
parent 0db81e8e20
commit 476316bb48
3 changed files with 7 additions and 51 deletions
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20
arch/x86/boot/header.S
View File

@ -155,26 +155,6 @@ section_table:
IMAGE_SCN_MEM_READ | \
IMAGE_SCN_MEM_EXECUTE # Characteristics
#
# The EFI application loader requires a relocation section
# because EFI applications must be relocatable. The .reloc
# offset & size fields are filled in by build.c.
#
.ascii ".reloc"
.byte 0
.byte 0
.long 0
.long 0
.long 0 # SizeOfRawData
.long 0 # PointerToRawData
.long 0 # PointerToRelocations
.long 0 # PointerToLineNumbers
.word 0 # NumberOfRelocations
.word 0 # NumberOfLineNumbers
.long IMAGE_SCN_CNT_INITIALIZED_DATA | \
IMAGE_SCN_MEM_READ | \
IMAGE_SCN_MEM_DISCARDABLE # Characteristics
#ifdef CONFIG_EFI_MIXED
#
# The offset & size fields are filled in by build.c.

4
arch/x86/boot/setup.ld
View File

@ -40,8 +40,8 @@ SECTIONS
setup_sig = .;
LONG(0x5a5aaa55)
/* Reserve some extra space for the reloc and compat sections */
setup_size = ALIGN(ABSOLUTE(.) + 64, 512);
/* Reserve some extra space for the compat section */
setup_size = ALIGN(ABSOLUTE(.) + 32, 512);
setup_sects = ABSOLUTE(setup_size / 512);
}

34
arch/x86/boot/tools/build.c
View File

@ -47,7 +47,6 @@ typedef unsigned int u32;
/* This must be large enough to hold the entire setup */
u8 buf[SETUP_SECT_MAX*512];
#define PECOFF_RELOC_RESERVE 0x20
#define PECOFF_COMPAT_RESERVE 0x20
static unsigned long efi32_pe_entry;
@ -180,24 +179,13 @@ static void update_pecoff_section_header(char *section_name, u32 offset, u32 siz
update_pecoff_section_header_fields(section_name, offset, size, size, offset);
}
static void update_pecoff_setup_and_reloc(unsigned int size)
static void update_pecoff_setup(unsigned int size)
{
u32 setup_offset = 0x200;
u32 reloc_offset = size - PECOFF_RELOC_RESERVE - PECOFF_COMPAT_RESERVE;
#ifdef CONFIG_EFI_MIXED
u32 compat_offset = reloc_offset + PECOFF_RELOC_RESERVE;
#endif
u32 setup_size = reloc_offset - setup_offset;
u32 compat_offset = size - PECOFF_COMPAT_RESERVE;
u32 setup_size = compat_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]);
#ifdef CONFIG_EFI_MIXED
update_pecoff_section_header(".compat", compat_offset, PECOFF_COMPAT_RESERVE);
@ -214,21 +202,10 @@ static void update_pecoff_setup_and_reloc(unsigned int size)
#endif
}
static int reserve_pecoff_reloc_section(int c)
{
/* Reserve 0x20 bytes for .reloc section */
memset(buf+c, 0, PECOFF_RELOC_RESERVE);
return PECOFF_RELOC_RESERVE;
}
#else
static inline void update_pecoff_setup_and_reloc(unsigned int size) {}
static inline void update_pecoff_setup(unsigned int size) {}
static inline int reserve_pecoff_reloc_section(int c)
{
return 0;
}
#endif /* CONFIG_EFI_STUB */
static int reserve_pecoff_compat_section(int c)
@ -307,7 +284,6 @@ int main(int argc, char ** argv)
fclose(file);
c += reserve_pecoff_compat_section(c);
c += reserve_pecoff_reloc_section(c);
/* Pad unused space with zeros */
setup_sectors = (c + 511) / 512;
@ -316,7 +292,7 @@ int main(int argc, char ** argv)
i = setup_sectors*512;
memset(buf+c, 0, i-c);
update_pecoff_setup_and_reloc(i);
update_pecoff_setup(i);
/* Open and stat the kernel file */
fd = open(argv[2], O_RDONLY);