linux/arch/x86/entry/Makefile
Andrea Righi de979c8357 x86/entry: Build thunk_$(BITS) only if CONFIG_PREEMPTION=y
With CONFIG_PREEMPTION disabled, arch/x86/entry/thunk_$(BITS).o becomes
an empty object file.

With some old versions of binutils (i.e., 2.35.90.20210113-1ubuntu1) the
GNU assembler doesn't generate a symbol table for empty object files and
objtool fails with the following error when a valid symbol table cannot
be found:

  arch/x86/entry/thunk_64.o: warning: objtool: missing symbol table

To prevent this from happening, build thunk_$(BITS).o only if
CONFIG_PREEMPTION is enabled.

BugLink: https://bugs.launchpad.net/bugs/1911359

Fixes: 320100a5ff ("x86/entry: Remove the TRACE_IRQS cruft")
Signed-off-by: Andrea Righi <andrea.righi@canonical.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/Ys/Ke7EWjcX+ZlXO@arighi-desktop
2022-08-04 12:23:50 +02:00

24 lines
503 B
Makefile

# SPDX-License-Identifier: GPL-2.0
#
# Makefile for the x86 low level entry code
#
KASAN_SANITIZE := n
UBSAN_SANITIZE := n
KCOV_INSTRUMENT := n
CFLAGS_REMOVE_common.o = $(CC_FLAGS_FTRACE)
CFLAGS_common.o += -fno-stack-protector
obj-y := entry.o entry_$(BITS).o syscall_$(BITS).o
obj-y += common.o
obj-y += vdso/
obj-y += vsyscall/
obj-$(CONFIG_PREEMPTION) += thunk_$(BITS).o
obj-$(CONFIG_IA32_EMULATION) += entry_64_compat.o syscall_32.o
obj-$(CONFIG_X86_X32_ABI) += syscall_x32.o