linux-stable/arch/arm64/kernel/Makefile
Ard Biesheuvel d104a6fef3 arm64: scs: Disable LTO for SCS patching code
Full LTO takes the '-mbranch-protection=none' passed to the compiler
when generating the dynamic shadow call stack patching code as a hint to
stop emitting PAC instructions altogether. (Thin LTO appears unaffected
by this)

Work around this by disabling LTO for the compilation unit, which
appears to convince the linker that it should still use PAC in the rest
of the kernel..

Fixes: 3b619e22c4 ("arm64: implement dynamic shadow call stack for Clang")
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Sami Tolvanen <samitolvanen@google.com>
Tested-by: Sami Tolvanen <samitolvanen@google.com>
Link: https://lore.kernel.org/r/20240123133052.1417449-6-ardb+git@google.com
Signed-off-by: Will Deacon <will@kernel.org>
2024-01-30 11:52:46 +00:00

97 lines
3.8 KiB
Makefile

# SPDX-License-Identifier: GPL-2.0
#
# Makefile for the linux kernel.
#
CFLAGS_armv8_deprecated.o := -I$(src)
CFLAGS_REMOVE_ftrace.o = $(CC_FLAGS_FTRACE)
CFLAGS_REMOVE_insn.o = $(CC_FLAGS_FTRACE)
CFLAGS_REMOVE_return_address.o = $(CC_FLAGS_FTRACE)
# Remove stack protector to avoid triggering unneeded stack canary
# checks due to randomize_kstack_offset.
CFLAGS_REMOVE_syscall.o = -fstack-protector -fstack-protector-strong
CFLAGS_syscall.o += -fno-stack-protector
# When KASAN is enabled, a stack trace is recorded for every alloc/free, which
# can significantly impact performance. Avoid instrumenting the stack trace
# collection code to minimize this impact.
KASAN_SANITIZE_stacktrace.o := n
# It's not safe to invoke KCOV when portions of the kernel environment aren't
# available or are out-of-sync with HW state. Since `noinstr` doesn't always
# inhibit KCOV instrumentation, disable it for the entire compilation unit.
KCOV_INSTRUMENT_entry-common.o := n
KCOV_INSTRUMENT_idle.o := n
# Object file lists.
obj-y := debug-monitors.o entry.o irq.o fpsimd.o \
entry-common.o entry-fpsimd.o process.o ptrace.o \
setup.o signal.o sys.o stacktrace.o time.o traps.o \
io.o vdso.o hyp-stub.o psci.o cpu_ops.o \
return_address.o cpuinfo.o cpu_errata.o \
cpufeature.o alternative.o cacheinfo.o \
smp.o smp_spin_table.o topology.o smccc-call.o \
syscall.o proton-pack.o idreg-override.o idle.o \
patching.o
obj-$(CONFIG_COMPAT) += sys32.o signal32.o \
sys_compat.o
obj-$(CONFIG_COMPAT) += sigreturn32.o
obj-$(CONFIG_COMPAT_ALIGNMENT_FIXUPS) += compat_alignment.o
obj-$(CONFIG_KUSER_HELPERS) += kuser32.o
obj-$(CONFIG_FUNCTION_TRACER) += ftrace.o entry-ftrace.o
obj-$(CONFIG_MODULES) += module.o module-plts.o
obj-$(CONFIG_PERF_EVENTS) += perf_regs.o perf_callchain.o
obj-$(CONFIG_HARDLOCKUP_DETECTOR_PERF) += watchdog_hld.o
obj-$(CONFIG_HAVE_HW_BREAKPOINT) += hw_breakpoint.o
obj-$(CONFIG_CPU_PM) += sleep.o suspend.o
obj-$(CONFIG_CPU_IDLE) += cpuidle.o
obj-$(CONFIG_JUMP_LABEL) += jump_label.o
obj-$(CONFIG_KGDB) += kgdb.o
obj-$(CONFIG_EFI) += efi.o efi-rt-wrapper.o
obj-$(CONFIG_PCI) += pci.o
obj-$(CONFIG_ARMV8_DEPRECATED) += armv8_deprecated.o
obj-$(CONFIG_ACPI) += acpi.o
obj-$(CONFIG_ACPI_NUMA) += acpi_numa.o
obj-$(CONFIG_ARM64_ACPI_PARKING_PROTOCOL) += acpi_parking_protocol.o
obj-$(CONFIG_PARAVIRT) += paravirt.o
obj-$(CONFIG_RANDOMIZE_BASE) += kaslr.o pi/
obj-$(CONFIG_HIBERNATION) += hibernate.o hibernate-asm.o
obj-$(CONFIG_ELF_CORE) += elfcore.o
obj-$(CONFIG_KEXEC_CORE) += machine_kexec.o relocate_kernel.o \
cpu-reset.o
obj-$(CONFIG_KEXEC_FILE) += machine_kexec_file.o kexec_image.o
obj-$(CONFIG_ARM64_RELOC_TEST) += arm64-reloc-test.o
arm64-reloc-test-y := reloc_test_core.o reloc_test_syms.o
obj-$(CONFIG_CRASH_DUMP) += crash_dump.o
obj-$(CONFIG_CRASH_CORE) += crash_core.o
obj-$(CONFIG_ARM_SDE_INTERFACE) += sdei.o
obj-$(CONFIG_ARM64_PTR_AUTH) += pointer_auth.o
obj-$(CONFIG_ARM64_MTE) += mte.o
obj-y += vdso-wrap.o
obj-$(CONFIG_COMPAT_VDSO) += vdso32-wrap.o
obj-$(CONFIG_UNWIND_PATCH_PAC_INTO_SCS) += patch-scs.o
# We need to prevent the SCS patching code from patching itself. Using
# -mbranch-protection=none here to avoid the patchable PAC opcodes from being
# generated triggers an issue with full LTO on Clang, which stops emitting PAC
# instructions altogether. So disable LTO as well for the compilation unit.
CFLAGS_patch-scs.o += -mbranch-protection=none
CFLAGS_REMOVE_patch-scs.o += $(CC_FLAGS_LTO)
# Force dependency (vdso*-wrap.S includes vdso.so through incbin)
$(obj)/vdso-wrap.o: $(obj)/vdso/vdso.so
$(obj)/vdso32-wrap.o: $(obj)/vdso32/vdso.so
obj-y += probes/
obj-y += head.o
extra-y += vmlinux.lds
ifeq ($(CONFIG_DEBUG_EFI),y)
AFLAGS_head.o += -DVMLINUX_PATH="\"$(realpath $(objtree)/vmlinux)\""
endif
# for cleaning
subdir- += vdso vdso32