kernel/linux.git/include/linux/init.h, branch v6.18.21

x86/cfi: Remove noinitretpoline and noretpoline

2025-09-04T19:59:08+00:00

Commit 66f793099a63 ("x86/retpoline: Avoid retpolines for built-in __init functions") disabled retpolines in __init sections (__noinitretpoline) as a precaution against potential issues with retpolines in early boot, but it has not been a problem in practice (i.e. see Clang below). Commit 87358710c1fb ("x86/retpoline: Support retpoline builds with Clang") narrowed this to only GCC, as Clang doesn't have per-function control over retpoline emission. As such, Clang has been booting with retpolines in __init since retpoline support was introduced. Clang KCFI has been instrumenting __init since CFI was introduced. With the introduction of KCFI for GCC, KCFI instrumentation with retpolines disabled means that objtool does not construct .retpoline_sites section entries for the non-retpoline KCFI calls. At boot, the KCFI rehashing code, via __apply_fineibt(), misses all __init KCFI calls (since they are not retpolines), resulting in immediate hash mismatches: all preambles are rehashed (via .cfi_sites) and none of the __init call sites are rehashed. Remove __noinitretpoline since it provides no meaningful utility and creates problems with CFI. Additionally remove __noretpoline since it is now unused. Alternatively, cfi_rand_callers() could walk the .kcfi_traps section which is exactly the list of KCFI instrumentation sites. But it seems better to have as few differences in common instruction sequences between compilers as possible, so better to remove the special handling of retpolines in __init for GCC. Signed-off-by: Kees Cook Signed-off-by: Peter Zijlstra (Intel) Link: https://lore.kernel.org/r/20250904034656.3670313-6-kees@kernel.org

compiler_types: Provide __no_kstack_erase to disable coverage only on Clang

2025-07-30T00:19:35+00:00

In order to support Clang's stack depth tracking (for Linux's kstack_erase feature), the coverage sanitizer needed to be disabled for __init (and __head) section code. Doing this universally (i.e. for GCC too) created a number of unexpected problems, ranging from changes to inlining logic to failures to DCE code on earlier GCC versions. Since this change is only needed for Clang, specialize it so that GCC doesn't see the change as it isn't needed there (the GCC implementation of kstack_erase uses a GCC plugin that removes stack depth tracking instrumentation from __init sections during a late pass in the IR). Successfully build and boot tested with GCC 12 and Clang 22. Fixes: 381a38ea53d2 ("init.h: Disable sanitizer coverage for __init and __head") Reported-by: kernel test robot Closes: https://lore.kernel.org/oe-kbuild-all/202507270258.neWuiXLd-lkp@intel.com/ Reported-by: syzbot+5245cb609175fb6e8122@syzkaller.appspotmail.com Closes: https://lore.kernel.org/all/6888d004.a00a0220.26d0e1.0004.GAE@google.com/ Reviewed-by: Nathan Chancellor Reviewed-by: Marco Elver Link: https://lore.kernel.org/r/20250729234055.it.233-kees@kernel.org Signed-off-by: Kees Cook

init.h: Disable sanitizer coverage for init and head

2025-07-26T21:28:35+00:00

While __noinstr already contained __no_sanitize_coverage, it needs to be added to __init and __head section markings to support the Clang implementation of CONFIG_KSTACK_ERASE. This is to make sure the stack depth tracking callback is not executed in unsupported contexts. The other sanitizer coverage options (trace-pc and trace-cmp) aren't needed in __head nor __init either ("We are interested in code coverage as a function of a syscall inputs"[1]), so this is fine to disable for them as well. Link: https://web.git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/kernel/kcov.c?h=v6.14#n179 [1] Acked-by: Marco Elver Link: https://lore.kernel.org/r/20250724055029.3623499-3-kees@kernel.org Signed-off-by: Kees Cook

init/modpost: conditionally check section mismatch to __meminit*

2024-07-12T23:39:52+00:00

This reverts commit eb8f689046b8 ("Use separate sections for __dev/ _cpu/__mem code/data"). Check section mismatch to __meminit* only when CONFIG_MEMORY_HOTPLUG=n. With this change, the linker script and modpost become simpler, and we can get rid of the __ref annotations from the memory hotplug code. [sfr@canb.auug.org.au: remove MEM_KEEP from arch/powerpc/kernel/vmlinux.lds.S] Link: https://lkml.kernel.org/r/20240710093213.2aefb25f@canb.auug.org.au Link: https://lkml.kernel.org/r/20240706160511.2331061-2-masahiroy@kernel.org Signed-off-by: Masahiro Yamada Signed-off-by: Stephen Rothwell Reviewed-by: Wei Yang Cc: Stephen Rothwell Signed-off-by: Andrew Morton

init: remove unused __MEMINIT* macros

2024-07-12T23:39:52+00:00

These macros are not used anywhere. Link: https://lkml.kernel.org/r/20240706160511.2331061-1-masahiroy@kernel.org Signed-off-by: Masahiro Yamada Reviewed-by: Wei Yang Signed-off-by: Andrew Morton

init: Declare rodata_enabled and mark_rodata_ro() at all time

2024-02-02T18:21:25+00:00

Declaring rodata_enabled and mark_rodata_ro() at all time helps removing related #ifdefery in C files. Signed-off-by: Christophe Leroy Signed-off-by: Luis Chamberlain

init: move THIS_MODULE from to

2023-12-10T06:32:48+00:00

Commit f50169324df4 ("module.h: split out the EXPORT_SYMBOL into export.h") appropriately separated EXPORT_SYMBOL into because modules and EXPORT_SYMBOL are orthogonal; modules are symbol consumers, while EXPORT_SYMBOL are used by symbol providers, which may not be necessarily a module. However, that commit also relocated THIS_MODULE. As explained in the commit description, the intention was to define THIS_MODULE in a lightweight header, but I do not believe was the best location because EXPORT_SYMBOL and THIS_MODULE are unrelated. Move it to another lightweight header, . The reason for choosing is to make self-contained without relying on incorrectly including . With this adjustment, the role of becomes clearer as it only defines EXPORT_SYMBOL. Signed-off-by: Masahiro Yamada Reviewed-by: Luis Chamberlain

linux/init: remove __memexit* annotations

2023-10-28T12:31:22+00:00

We have never used __memexit, __memexitdata, or __memexitconst. These were unneeded. Signed-off-by: Masahiro Yamada Acked-by: Arnd Bergmann

x86/mem_encrypt: Remove stale mem_encrypt_init() declaration

2023-06-28T19:47:30+00:00

The memory encryption initialization logic was moved from init/main.c into arch_cpu_finalize_init() in commit 439e17576eb4 ("init, x86: Move mem_encrypt_init() into arch_cpu_finalize_init()"), but a stale declaration for the init function was left in . And didn't cause any problems if you had X86_MEM_ENCRYPT enabled, which apparently everybody involved did have. See also commit 0a9567ac5e6a ("x86/mem_encrypt: Unbreak the AMD_MEM_ENCRYPT=n build") in this whole sad saga of conflicting declarations for different situations. Reported-by: Matthew Wilcox Fixes: 439e17576eb4 init, x86: Move mem_encrypt_init() into arch_cpu_finalize_init() Cc: Thomas Gleixner Signed-off-by: Linus Torvalds

init: consolidate prototypes in linux/init.h

2023-06-10T00:44:16+00:00

The init/main.c file contains some extern declarations for functions defined in architecture code, and it defines some other functions that are called from architecture code with a custom prototype. Both of those result in warnings with 'make W=1': init/calibrate.c:261:37: error: no previous prototype for 'calibrate_delay_is_known' [-Werror=missing-prototypes] init/main.c:790:20: error: no previous prototype for 'mem_encrypt_init' [-Werror=missing-prototypes] init/main.c:792:20: error: no previous prototype for 'poking_init' [-Werror=missing-prototypes] arch/arm64/kernel/irq.c:122:13: error: no previous prototype for 'init_IRQ' [-Werror=missing-prototypes] arch/arm64/kernel/time.c:55:13: error: no previous prototype for 'time_init' [-Werror=missing-prototypes] arch/x86/kernel/process.c:935:13: error: no previous prototype for 'arch_post_acpi_subsys_init' [-Werror=missing-prototypes] init/calibrate.c:261:37: error: no previous prototype for 'calibrate_delay_is_known' [-Werror=missing-prototypes] kernel/fork.c:991:20: error: no previous prototype for 'arch_task_cache_init' [-Werror=missing-prototypes] Add prototypes for all of these in include/linux/init.h or another appropriate header, and remove the duplicate declarations from architecture specific code. [sfr@canb.auug.org.au: declare time_init_early()] Link: https://lkml.kernel.org/r/20230519124311.5167221c@canb.auug.org.au Link: https://lkml.kernel.org/r/20230517131102.934196-12-arnd@kernel.org Signed-off-by: Arnd Bergmann Signed-off-by: Stephen Rothwell Cc: Boqun Feng Cc: Catalin Marinas Cc: Christoph Lameter Cc: Dennis Zhou Cc: Eric Paris Cc: Heiko Carstens Cc: Helge Deller Cc: Ingo Molnar Cc: Michael Ellerman Cc: Michal Simek Cc: Palmer Dabbelt Cc: Paul Moore Cc: Pavel Machek Cc: Peter Zijlstra Cc: Rafael J. Wysocki Cc: Russell King Cc: Tejun Heo Cc: Thomas Bogendoerfer Cc: Thomas Gleixner Cc: Waiman Long Cc: Will Deacon Signed-off-by: Andrew Morton