Josh Poimboeuf 9c7dc1dd89 objtool: Warn on functions with ambiguous -ffunction-sections section names ... When compiled with -ffunction-sections, a function named startup() will be placed in .text.startup. However, .text.startup is also used by the compiler for functions with __attribute__((constructor)). That creates an ambiguity for the vmlinux linker script, which needs to differentiate those two cases. Similar naming conflicts exist for functions named exit(), split(), unlikely(), hot() and unknown(). One potential solution would be to use '#ifdef CC_USING_FUNCTION_SECTIONS' to create two distinct implementations of the TEXT_MAIN macro. However, -ffunction-sections can be (and is) enabled or disabled on a per-object basis (for example via ccflags-y or AUTOFDO_PROFILE). So the recently unified TEXT_MAIN macro (commit 1ba9f89794 ("vmlinux.lds: Unify TEXT_MAIN, DATA_MAIN, and related macros")) is necessary. This means there's no way for the linker script to disambiguate things. Instead, use objtool to warn on any function names whose resulting section names might create ambiguity when the kernel is compiled (in whole or in part) with -ffunction-sections. Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: live-patching@vger.kernel.org Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: https://patch.msgid.link/65fedea974fe14be487c8867a0b8d0e4a294ce1e.1762991150.git.jpoimboe@kernel.org		2025-11-13 08:03:10 +01:00
..
bitops	bitops: Add __attribute_const__ to generic ffs()-family implementations	2025-09-08 14:58:50 -07:00
vdso	vdso: Drop Kconfig GENERIC_VDSO_DATA_STORE	2025-09-04 11:23:50 +02:00
access_ok.h	uaccess: remove CONFIG_SET_FS	2022-02-25 09:36:06 +01:00
agp.h	char/agp: introduce asm-generic/agp.h	2023-02-13 22:13:29 +01:00
archrandom.h	random: handle archrandom with multiple longs	2022-07-25 13:26:14 +02:00
asm-offsets.h
asm-prototypes.h
atomic.h	locking/atomic: make atomic*_{cmp,}xchg optional	2023-06-05 09:57:14 +02:00
atomic64.h	locking/atomic: delete !ARCH_ATOMIC remnants	2021-05-26 13:20:52 +02:00
audit_change_attr.h	fs/xattr: add *at family syscalls	2024-11-06 12:59:44 -05:00
audit_dir_write.h
audit_read.h
audit_signal.h
audit_write.h
barrier.h	sched: Add missing memory barrier in switch_mm_cid	2024-04-16 13:59:45 +02:00
bitops.h	include: move find.h from asm_generic to linux	2022-01-15 08:47:31 -08:00
bitsperlong.h	lib: extend the scope of small_const_nbits() macro	2021-05-06 19:24:11 -07:00
bug.h	bug: Improve comment	2024-05-07 14:20:48 +02:00
cache.h
cacheflush.h	mm: Introduce flush_cache_vmap_early()	2023-12-14 00:23:17 -08:00
cfi.h	cfi: Flip headers	2023-12-15 16:25:55 -08:00
checksum.h	asm-generic: Improve csum_fold	2024-01-17 17:52:29 -08:00
cmpxchg-local.h	asm-generic: Fix 32 bit __generic_cmpxchg_local	2024-01-05 23:19:14 +01:00
cmpxchg.h	asm-generic: avoid __generic_cmpxchg_local warnings	2023-04-04 17:58:11 +02:00
codetag.lds.h	codetag: avoid unused alloc_tags sections/symbols	2025-07-09 22:42:14 -07:00
compat.h	asm-generic: compat: fix compat_arg_u64() and compat_arg_u64_dual()	2022-11-01 10:20:11 +11:00
current.h	asm-generic: current: Don't include thread-info.h if building asm	2023-08-26 22:38:49 +02:00
delay.h	delay: Fix ndelay() spuriously treated as udelay()	2024-11-29 11:40:22 +01:00
device.h
div64.h	__arch_xprod64(): make __always_inline when optimizing for performance	2024-10-28 21:44:28 +00:00
dma-mapping.h	dma-mapping: no need to pass a bus_type into get_arch_dma_ops()	2023-02-15 12:35:20 +01:00
dma.h
early_ioremap.h	mm/early_ioremap: add null pointer checks to prevent NULL-pointer dereference	2025-01-13 22:40:59 -08:00
emergency-restart.h
error-injection.h	docs: fault-injection: add requirements of error injectable functions	2023-02-02 22:50:00 -08:00
exec.h
extable.h
fixmap.h	fixmap: Remove unused set_fixmap_offset_io()	2024-07-11 17:41:23 +02:00
flat.h
fprobe.h	fprobe: Add fprobe_header encoding feature	2024-12-26 10:50:05 -05:00
ftrace.h
futex.h	futex: Fix additional regressions	2021-12-11 23:31:51 +01:00
getorder.h	asm-generic: force inlining of get_order() to work around gcc10 poor decision	2020-12-15 22:46:15 -08:00
hardirq.h	irqstat: Move declaration into asm-generic/hardirq.h	2020-11-23 10:31:06 +01:00
hugetlb.h	mm: drop hugetlb_free_pgd_range()	2025-07-24 19:12:32 -07:00
hw_irq.h
int-ll64.h
io.h	asm-generic/io.h: Skip trace helpers if rwmmio events are disabled	2025-09-24 16:21:13 +02:00
ioctl.h
iomap.h	asm-generic/io.h: rework split ioread64/iowrite64 helpers	2025-03-01 21:00:22 +01:00
irq.h
irq_regs.h
irq_work.h
irqflags.h
Kbuild	unwind_user: Add user space unwinding API with frame pointer support	2025-07-29 14:46:07 -04:00
kdebug.h
kmap_size.h	mm/highmem: Provide and use CONFIG_DEBUG_KMAP_LOCAL	2020-11-24 14:42:08 +01:00
kprobes.h	treewide: Convert macro and uses of __section(foo) to __section("foo")	2020-10-25 14:51:49 -07:00
kvm_para.h
kvm_types.h	KVM: Move x86's version of struct kvm_mmu_memory_cache to common code	2020-07-09 13:29:42 -04:00
linkage.h
local.h	locking/generic: Wire up local{,64}_try_cmpxchg()	2023-04-29 09:09:09 +02:00
local64.h	locking/generic: Wire up local{,64}_try_cmpxchg()	2023-04-29 09:09:09 +02:00
logic_io.h	logic_io instance of iounmap() needs volatile on argument	2021-12-21 21:31:08 +01:00
mcs_spinlock.h	locking: Move MCS struct definition to public header	2025-03-18 10:28:21 -07:00
memory_model.h	mm: convert page_to_section() to memdesc_section()	2025-09-13 16:55:07 -07:00
mm_hooks.h	mm: remove arch_unmap()	2024-09-01 20:26:13 -07:00
mmiowb.h	asm-generic/mmiowb: Allow mmiowb_set_pending() when preemptible()	2020-07-17 10:02:03 +01:00
mmiowb_types.h
mmu.h
mmu_context.h	asm-generic: add generic MMU versions of mmu context functions	2020-10-26 16:45:03 +01:00
mmzone.h	arch, mm: move definition of node_data to generic code	2024-09-03 21:15:28 -07:00
module.h	asm-generic: Always define Elf_Rel and Elf_Rela	2025-03-26 15:56:43 -07:00
module.lds.h	kbuild: preprocess module linker script	2020-09-25 00:36:41 +09:00
mshyperv.h	Drivers: hv: Add CONFIG_HYPERV_VMBUS option	2025-10-01 00:00:42 +00:00
msi.h	irqchip/gic-v5: Add GICv5 IWB support	2025-07-08 18:35:52 +01:00
nommu_context.h	asm-generic: add generic MMU versions of mmu context functions	2020-10-26 16:45:03 +01:00
numa.h	arch_numa: switch over to numa_memblks	2024-09-03 21:15:32 -07:00
param.h	alpha: regularize the situation with asm/param.h	2025-06-24 22:02:05 -04:00
parport.h
pci.h	asm-generic: Add new pci.h and use it	2022-07-22 17:34:57 -05:00
pci_iomap.h	PCI: Stub __pci_ioport_map() for arches that don't support it at all	2022-07-29 12:01:00 -05:00
percpu.h	percpu: repurpose __percpu tag as a named address space qualifier	2025-03-16 22:05:53 -07:00
pgalloc.h	mm: call ctor/dtor for kernel PTEs	2025-05-11 17:48:21 -07:00
pgtable-nop4d.h	mm: rename p4d_page_vaddr to p4d_pgtable and make it return pud_t *	2021-07-08 11:48:22 -07:00
pgtable-nopmd.h	mm: recover pud_leaf() definitions in nopmd case	2024-03-13 12:12:21 -07:00
pgtable-nopud.h	mm: rename p4d_page_vaddr to p4d_pgtable and make it return pud_t *	2021-07-08 11:48:22 -07:00
pgtable_uffd.h
preempt.h	riscv: support PREEMPT_DYNAMIC with static keys	2023-08-31 00:18:34 -07:00
qrwlock.h	asm-generic changes for 5.19	2022-05-26 10:50:30 -07:00
qrwlock_types.h	locking/qrwlock: Change "queue rwlock" to "queued rwlock"	2022-05-11 16:27:04 +02:00
qspinlock.h	riscv: Add qspinlock support	2024-11-11 07:33:20 -08:00
qspinlock_types.h	locking/qspinlock: Do not include atomic.h from qspinlock_types.h	2020-07-29 16:14:19 +02:00
resource.h
rqspinlock.h	bpf: Introduce rqspinlock kfuncs	2025-03-19 08:03:06 -07:00
runtime-const.h	runtime constants: add default dummy infrastructure	2024-06-19 12:34:34 -07:00
rwonce.h	rwonce: fix crash by removing READ_ONCE() for unaligned read	2025-03-26 22:16:50 +01:00
seccomp.h	seccomp: Use -1 marker for end of mode 1 syscall list	2020-07-10 16:01:52 -07:00
sections.h	percpu: Remove __per_cpu_load	2025-02-18 10:16:00 +01:00
serial.h
set_memory.h
shmparam.h
signal.h	asm-generic: Remove empty #ifdef SA_RESTORER	2022-09-10 09:56:53 +02:00
simd.h	asm-generic: Add sched.h inclusion in simd.h	2025-05-30 20:56:48 +08:00
softirq_stack.h	asm-generic: Conditionally enable do_softirq_own_stack() via Kconfig.	2022-09-05 17:20:55 +02:00
spinlock.h	asm-generic: ticket-lock: Add separate ticket-lock.h	2024-11-11 07:33:17 -08:00
spinlock_types.h	asm-generic: ticket-lock: Reuse arch_spinlock_t of qspinlock	2024-11-11 07:33:16 -08:00
statfs.h
string.h
switch_to.h
syscall.h	syscall.h: introduce syscall_set_nr()	2025-05-11 17:48:15 -07:00
syscalls.h	syscalls: mmap(): use unsigned offset type consistently	2024-06-25 15:57:38 +02:00
text-patching.h	asm-generic: introduce text-patching.h	2024-11-07 14:25:15 -08:00
thread_info_tif.h	asm-generic: Provide generic TIF infrastructure	2025-09-17 08:14:03 +02:00
ticket_spinlock.h	riscv: Add qspinlock support	2024-11-11 07:33:20 -08:00
timex.h
tlb.h	mmu_gather: move tlb flush for VM_PFNMAP/VM_MIXEDMAP vmas into free_pgtables()	2025-05-31 22:46:12 -07:00
tlbflush.h
topology.h	mm: replace CONFIG_NEED_MULTIPLE_NODES with CONFIG_NUMA	2021-06-29 10:53:55 -07:00
trace_clock.h
uaccess.h	move asm/unaligned.h to linux/unaligned.h	2024-10-02 17:23:23 -04:00
unwind_user.h	unwind_user: Add user space unwinding API with frame pointer support	2025-07-29 14:46:07 -04:00
user.h
vermagic.h
vga.h	empty include/asm-generic/vga.h	2024-11-11 21:51:42 +01:00
video.h	arch: Rename fbdev header and source files	2024-05-03 17:07:50 +02:00
vmlinux.lds.h	objtool: Warn on functions with ambiguous -ffunction-sections section names	2025-11-13 08:03:10 +01:00
word-at-a-time.h	kernel.h: removed REPEAT_BYTE from kernel.h	2024-02-01 09:47:59 -08:00
xor.h	lib/xor: make xor prototypes more friendly to compiler vectorization	2022-02-11 20:39:39 +11:00