From 7621712918ad4f5e6356193d9058debf657a6254 Mon Sep 17 00:00:00 2001 From: David Brazdil <dbrazdil@google.com> Date: Thu, 25 Jun 2020 14:14:08 +0100 Subject: [PATCH] KVM: arm64: Add build rules for separate VHE/nVHE object files Add new folders arch/arm64/kvm/hyp/{vhe,nvhe} and Makefiles for building code that runs in EL2 under VHE/nVHE KVM, repsectivelly. Add an include folder for hyp-specific header files which will include code common to VHE/nVHE. Build nVHE code with -D__KVM_NVHE_HYPERVISOR__, VHE code with -D__KVM_VHE_HYPERVISOR__. Under nVHE compile each source file into a `.hyp.tmp.o` object first, then prefix all its symbols with "__kvm_nvhe_" using `objcopy` and produce a `.hyp.o`. Suffixes were chosen so that it would be possible for VHE and nVHE to share some source files, but compiled with different CFLAGS. The nVHE ELF symbol prefix is added to kallsyms.c as ignored. EL2-only symbols will never appear in EL1 stack traces. Due to symbol prefixing, add a section in image-vars.h for aliases of symbols that are defined in nVHE EL2 and accessed by kernel in EL1 or vice versa. Signed-off-by: David Brazdil <dbrazdil@google.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20200625131420.71444-4-dbrazdil@google.com --- arch/arm64/kernel/image-vars.h | 14 +++++++++++++ arch/arm64/kvm/hyp/Makefile | 10 +++++++--- arch/arm64/kvm/hyp/nvhe/Makefile | 34 ++++++++++++++++++++++++++++++++ arch/arm64/kvm/hyp/vhe/Makefile | 17 ++++++++++++++++ scripts/kallsyms.c | 1 + 5 files changed, 73 insertions(+), 3 deletions(-) create mode 100644 arch/arm64/kvm/hyp/nvhe/Makefile create mode 100644 arch/arm64/kvm/hyp/vhe/Makefile diff --git a/arch/arm64/kernel/image-vars.h b/arch/arm64/kernel/image-vars.h index be0a63ffed23..3dc27da47712 100644 --- a/arch/arm64/kernel/image-vars.h +++ b/arch/arm64/kernel/image-vars.h @@ -51,4 +51,18 @@ __efistub__ctype = _ctype; #endif +#ifdef CONFIG_KVM + +/* + * KVM nVHE code has its own symbol namespace prefixed with __kvm_nvhe_, to + * separate it from the kernel proper. The following symbols are legally + * accessed by it, therefore provide aliases to make them linkable. + * Do not include symbols which may not be safely accessed under hypervisor + * memory mappings. + */ + +#define KVM_NVHE_ALIAS(sym) __kvm_nvhe_##sym = sym; + +#endif /* CONFIG_KVM */ + #endif /* __ARM64_KERNEL_IMAGE_VARS_H */ diff --git a/arch/arm64/kvm/hyp/Makefile b/arch/arm64/kvm/hyp/Makefile index 5d8357ddc234..9c5dfe6ff80b 100644 --- a/arch/arm64/kvm/hyp/Makefile +++ b/arch/arm64/kvm/hyp/Makefile @@ -3,10 +3,14 @@ # Makefile for Kernel-based Virtual Machine module, HYP part # -ccflags-y += -fno-stack-protector -DDISABLE_BRANCH_PROFILING \ - $(DISABLE_STACKLEAK_PLUGIN) +incdir := $(srctree)/$(src)/include +subdir-asflags-y := -I$(incdir) +subdir-ccflags-y := -I$(incdir) \ + -fno-stack-protector \ + -DDISABLE_BRANCH_PROFILING \ + $(DISABLE_STACKLEAK_PLUGIN) -obj-$(CONFIG_KVM) += hyp.o +obj-$(CONFIG_KVM) += hyp.o nvhe/ obj-$(CONFIG_KVM_INDIRECT_VECTORS) += smccc_wa.o hyp-y := vgic-v3-sr.o timer-sr.o aarch32.o vgic-v2-cpuif-proxy.o sysreg-sr.o \ diff --git a/arch/arm64/kvm/hyp/nvhe/Makefile b/arch/arm64/kvm/hyp/nvhe/Makefile new file mode 100644 index 000000000000..955f4188e00f --- /dev/null +++ b/arch/arm64/kvm/hyp/nvhe/Makefile @@ -0,0 +1,34 @@ +# SPDX-License-Identifier: GPL-2.0 +# +# Makefile for Kernel-based Virtual Machine module, HYP/nVHE part +# + +asflags-y := -D__KVM_NVHE_HYPERVISOR__ +ccflags-y := -D__KVM_NVHE_HYPERVISOR__ + +obj-y := + +obj-y := $(patsubst %.o,%.hyp.o,$(obj-y)) +extra-y := $(patsubst %.hyp.o,%.hyp.tmp.o,$(obj-y)) + +$(obj)/%.hyp.tmp.o: $(src)/%.c FORCE + $(call if_changed_rule,cc_o_c) +$(obj)/%.hyp.tmp.o: $(src)/%.S FORCE + $(call if_changed_rule,as_o_S) +$(obj)/%.hyp.o: $(obj)/%.hyp.tmp.o FORCE + $(call if_changed,hypcopy) + +quiet_cmd_hypcopy = HYPCOPY $@ + cmd_hypcopy = $(OBJCOPY) --prefix-symbols=__kvm_nvhe_ $< $@ + +# KVM nVHE code is run at a different exception code with a different map, so +# compiler instrumentation that inserts callbacks or checks into the code may +# cause crashes. Just disable it. +GCOV_PROFILE := n +KASAN_SANITIZE := n +UBSAN_SANITIZE := n +KCOV_INSTRUMENT := n + +# Skip objtool checking for this directory because nVHE code is compiled with +# non-standard build rules. +OBJECT_FILES_NON_STANDARD := y diff --git a/arch/arm64/kvm/hyp/vhe/Makefile b/arch/arm64/kvm/hyp/vhe/Makefile new file mode 100644 index 000000000000..e04375546081 --- /dev/null +++ b/arch/arm64/kvm/hyp/vhe/Makefile @@ -0,0 +1,17 @@ +# SPDX-License-Identifier: GPL-2.0 +# +# Makefile for Kernel-based Virtual Machine module, HYP/nVHE part +# + +asflags-y := -D__KVM_VHE_HYPERVISOR__ +ccflags-y := -D__KVM_VHE_HYPERVISOR__ + +obj-y := + +# KVM code is run at a different exception code with a different map, so +# compiler instrumentation that inserts callbacks or checks into the code may +# cause crashes. Just disable it. +GCOV_PROFILE := n +KASAN_SANITIZE := n +UBSAN_SANITIZE := n +KCOV_INSTRUMENT := n diff --git a/scripts/kallsyms.c b/scripts/kallsyms.c index 6dc3078649fa..0096cd965332 100644 --- a/scripts/kallsyms.c +++ b/scripts/kallsyms.c @@ -109,6 +109,7 @@ static bool is_ignored_symbol(const char *name, char type) ".LASANPC", /* s390 kasan local symbols */ "__crc_", /* modversions */ "__efistub_", /* arm64 EFI stub namespace */ + "__kvm_nvhe_", /* arm64 non-VHE KVM namespace */ NULL }; -- 2.30.9