1# SPDX-License-Identifier: GPL-2.0 2# 3# Makefile for Kernel-based Virtual Machine module, HYP/nVHE part 4# 5 6asflags-y := -D__KVM_NVHE_HYPERVISOR__ -D__DISABLE_EXPORTS 7 8# Tracepoint and MMIO logging symbols should not be visible at nVHE KVM as 9# there is no way to execute them and any such MMIO access from nVHE KVM 10# will explode instantly (Words of Marc Zyngier). So introduce a generic flag 11# __DISABLE_TRACE_MMIO__ to disable MMIO tracing for nVHE KVM. 12ccflags-y := -D__KVM_NVHE_HYPERVISOR__ -D__DISABLE_EXPORTS -D__DISABLE_TRACE_MMIO__ 13ccflags-y += -fno-stack-protector \ 14 -DDISABLE_BRANCH_PROFILING \ 15 $(DISABLE_STACKLEAK_PLUGIN) 16 17HYPREL := arch/arm64/tools/gen-hyprel 18 19## 20## Build rules for compiling nVHE hyp code 21## Output of this folder is `kvm_nvhe.o`, a partially linked object 22## file containing all nVHE hyp code and data. 23## 24 25hyp-obj := $(patsubst %.o,%.nvhe.o,$(hyp-obj-y)) 26targets += $(hyp-obj) kvm_nvhe.tmp.o kvm_nvhe.rel.o hyp.lds hyp-reloc.S hyp-reloc.o 27 28# 1) Compile all source files to `.nvhe.o` object files. The file extension 29# avoids file name clashes for files shared with VHE. 30$(obj)/%.nvhe.o: $(src)/%.c FORCE 31 $(call if_changed_rule,cc_o_c) 32$(obj)/%.nvhe.o: $(src)/%.S FORCE 33 $(call if_changed_rule,as_o_S) 34 35# 2) Partially link all '.nvhe.o' files and apply the linker script. 36# Prefixes names of ELF sections with '.hyp', eg. '.hyp.text'. 37# Note: The following rule assumes that the 'ld' rule puts LDFLAGS before 38# the list of dependencies to form '-T $(obj)/hyp.lds'. This is to 39# keep the dependency on the target while avoiding an error from 40# GNU ld if the linker script is passed to it twice. 41LDFLAGS_kvm_nvhe.tmp.o := -r -T 42$(obj)/kvm_nvhe.tmp.o: $(obj)/hyp.lds $(addprefix $(obj)/,$(hyp-obj)) FORCE 43 $(call if_changed,ld) 44 45# 3) Generate list of hyp code/data positions that need to be relocated at 46# runtime. Because the hypervisor is part of the kernel binary, relocations 47# produce a kernel VA. We enumerate relocations targeting hyp at build time 48# and convert the kernel VAs at those positions to hyp VAs. 49$(obj)/hyp-reloc.S: $(obj)/kvm_nvhe.tmp.o FORCE 50 $(call if_changed,hyprel) 51 52# 4) Compile hyp-reloc.S and link it into the existing partially linked object. 53# The object file now contains a section with pointers to hyp positions that 54# will contain kernel VAs at runtime. These pointers have relocations on them 55# so that they get updated as the hyp object is linked into `vmlinux`. 56LDFLAGS_kvm_nvhe.rel.o := -r 57$(obj)/kvm_nvhe.rel.o: $(obj)/kvm_nvhe.tmp.o $(obj)/hyp-reloc.o FORCE 58 $(call if_changed,ld) 59 60# 5) Produce the final 'kvm_nvhe.o', ready to be linked into 'vmlinux'. 61# Prefixes names of ELF symbols with '__kvm_nvhe_'. 62$(obj)/kvm_nvhe.o: $(obj)/kvm_nvhe.rel.o FORCE 63 $(call if_changed,hypcopy) 64 65# The HYPREL command calls `gen-hyprel` to generate an assembly file with 66# a list of relocations targeting hyp code/data. 67quiet_cmd_hyprel = HYPREL $@ 68 cmd_hyprel = $(HYPREL) $< > $@ 69 70# The HYPCOPY command uses `objcopy` to prefix all ELF symbol names 71# to avoid clashes with VHE code/data. 72quiet_cmd_hypcopy = HYPCOPY $@ 73 cmd_hypcopy = $(OBJCOPY) --prefix-symbols=__kvm_nvhe_ $< $@ 74 75# Remove ftrace, Shadow Call Stack, and CFI CFLAGS. 76# This is equivalent to the 'notrace', '__noscs', and '__nocfi' annotations. 77KBUILD_CFLAGS := $(filter-out $(CC_FLAGS_FTRACE) $(CC_FLAGS_SCS) $(CC_FLAGS_CFI), $(KBUILD_CFLAGS)) 78# Starting from 13.0.0 llvm emits SHT_REL section '.llvm.call-graph-profile' 79# when profile optimization is applied. gen-hyprel does not support SHT_REL and 80# causes a build failure. Remove profile optimization flags. 81KBUILD_CFLAGS := $(filter-out -fprofile-sample-use=% -fprofile-use=%, $(KBUILD_CFLAGS)) 82KBUILD_CFLAGS += -fno-asynchronous-unwind-tables -fno-unwind-tables 83 84# KVM nVHE code is run at a different exception code with a different map, so 85# compiler instrumentation that inserts callbacks or checks into the code may 86# cause crashes. Just disable it. 87GCOV_PROFILE := n 88KASAN_SANITIZE := n 89UBSAN_SANITIZE := n 90KCOV_INSTRUMENT := n 91 92# Skip objtool checking for this directory because nVHE code is compiled with 93# non-standard build rules. 94OBJECT_FILES_NON_STANDARD := y 95