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boot: Lift linker requirements

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The biggest reason for forcing bfd was the use of linker scrips. Since
we don't rely on those anymore we can lift the requirement.

The biggest issue is gold as it does not understand -static-pie. Given
that it's pretty much on life support it's safe to just declare it not
supported anymore.

Don't link addons with libefi as clang/lld is sometimes very eager to
include memset etc., causing needless binary bloat and link errors with
LTO.

Fixes: #29165
This commit is contained in:
Jan Janssen
2023-09-29 16:56:30 +02:00
parent 898e9edc46
commit 0b042d3de8
1 changed files with 31 additions and 9 deletions
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src/boot/efi/meson.build
+31 -9
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@@ -147,10 +147,6 @@ if get_option('mode') == 'developer' and get_option('debug')
endif
efi_c_ld_args = [
# We only support bfd. gold is going away, lld has issues with LTO on x86
# and mold does not support linker scripts.
'-fuse-ld=bfd',
'-lgcc',
'-nostdlib',
'-static-pie',
@@ -170,9 +166,10 @@ efi_c_ld_args = [
'-z', 'separate-code',
]
# On CentOS 8 the nopack-relative-relocs linker flag is not supported, and we get:
# /usr/bin/ld.bfd: warning: -z nopack-relative-relocs ignored
efi_c_ld_args += cc.get_supported_link_arguments('-Wl,-z,nopack-relative-relocs')
efi_c_ld_args += cc.get_supported_link_arguments(
# binutils >= 2.38
'-Wl,-z,nopack-relative-relocs',
)
# efi_c_args is explicitly passed to targets so that they can override distro-provided flags
# that should not be used for EFI binaries.
@@ -213,11 +210,35 @@ efi_arch_c_args = {
efi_arch_c_ld_args = {
# libgcc is not compiled with -fshort-wchar, but it does not use it anyways,
# so it's fine to link against it.
'arm' : ['-Wl,--no-wchar-size-warning'],
'arm' : cc.get_supported_link_arguments('-Wl,--no-wchar-size-warning'),
'x86_64' : ['-m64'],
'x86' : ['-m32'],
}
linker_sanity_code = 'void a(void) {}; void _start(void) { a(); }'
linker_sanity_args = ['-nostdlib', '-Wl,--fatal-warnings']
if not cc.links(linker_sanity_code,
name : 'linker supports -static-pie',
args : [linker_sanity_args, '-static-pie'])
error('Linker does not support -static-pie.')
endif
# https://github.com/llvm/llvm-project/issues/67152
if not cc.links(linker_sanity_code,
name : 'linker supports LTO with -nostdlib',
args : [linker_sanity_args, '-flto'])
efi_c_args += '-fno-lto'
efi_c_ld_args += '-fno-lto'
endif
# https://github.com/llvm/llvm-project/issues/61101
if efi_cpu_family_alt == 'x86' and not cc.links(linker_sanity_code,
name : 'linker supports LTO with -nostdlib (x86)',
args : [linker_sanity_args, '-flto', '-m32'])
efi_arch_c_args += { 'x86' : efi_arch_c_args['x86'] + '-fno-lto' }
efi_arch_c_ld_args += { 'x86' : efi_arch_c_ld_args['x86'] + '-fno-lto' }
endif
############################################################
libefi_sources = files(
@@ -315,7 +336,6 @@ foreach archspec : efi_archspecs
'include_directories' : efi_includes,
'c_args' : archspec['c_args'],
'link_args' : archspec['link_args'],
'link_with' : libefi,
'gnu_symbol_visibility' : 'hidden',
'override_options' : efi_override_options,
'pie' : true,
@@ -324,12 +344,14 @@ foreach archspec : efi_archspecs
efi_elf_binaries += executable(
'systemd-boot' + archspec['arch'],
sources : [systemd_boot_sources, version_h],
link_with : libefi,
name_suffix : 'elf',
kwargs : kwargs)
efi_elf_binaries += executable(
'linux' + archspec['arch'],
sources : [stub_sources, version_h],
link_with : libefi,
name_suffix : 'elf.stub',
kwargs : kwargs)