kvm: arm64: Partially link nVHE hyp code, simplify HYPCOPY

/* SPDX-License-Identifier: GPL-2.0 */

/*

 * Copyright (C) 2020 Google LLC.

 * Written by David Brazdil <dbrazdil@google.com>

 */

#ifndef __ARM64_HYP_IMAGE_H__

#define __ARM64_HYP_IMAGE_H__

#ifdef LINKER_SCRIPT

/*

 * KVM nVHE ELF section names are prefixed with .hyp, to separate them

 * from the kernel proper.

 */

#define HYP_SECTION_NAME(NAME)	.hyp##NAME

/* Defines an ELF hyp section from input section @NAME and its subsections. */

#define HYP_SECTION(NAME) \

	HYP_SECTION_NAME(NAME) : { *(NAME NAME##.*) }

#endif /* LINKER_SCRIPT */

#endif /* __ARM64_HYP_IMAGE_H__ */

# SPDX-License-Identifier: GPL-2.0-only

hyp.lds

obj-y += ../vgic-v3-sr.o ../aarch32.o ../vgic-v2-cpuif-proxy.o ../entry.o \

	 ../fpsimd.o ../hyp-entry.o

obj-y := $(patsubst %.o,%.hyp.o,$(obj-y))

extra-y := $(patsubst %.hyp.o,%.hyp.tmp.o,$(obj-y))

##

## Build rules for compiling nVHE hyp code

## Output of this folder is `kvm_nvhe.o`, a partially linked object

## file containing all nVHE hyp code and data.

##

$(obj)/%.hyp.tmp.o: $(src)/%.c FORCE

hyp-obj := $(patsubst %.o,%.nvhe.o,$(obj-y))

obj-y := kvm_nvhe.o

extra-y := $(hyp-obj) kvm_nvhe.tmp.o hyp.lds

# 1) Compile all source files to `.nvhe.o` object files. The file extension

#    avoids file name clashes for files shared with VHE.

$(obj)/%.nvhe.o: $(src)/%.c FORCE

	$(call if_changed_rule,cc_o_c)

$(obj)/%.hyp.tmp.o: $(src)/%.S FORCE

$(obj)/%.nvhe.o: $(src)/%.S FORCE

	$(call if_changed_rule,as_o_S)

$(obj)/%.hyp.o: $(obj)/%.hyp.tmp.o FORCE

	$(call if_changed,hypcopy)

# Disable reordering functions by GCC (enabled at -O2).

# This pass puts functions into '.text.*' sections to aid the linker

# in optimizing ELF layout. See HYPCOPY comment below for more info.

ccflags-y += $(call cc-option,-fno-reorder-functions)

# 2) Compile linker script.

$(obj)/hyp.lds: $(src)/hyp.lds.S FORCE

	$(call if_changed_dep,cpp_lds_S)

# 3) Partially link all '.nvhe.o' files and apply the linker script.

#    Prefixes names of ELF sections with '.hyp', eg. '.hyp.text'.

#    Note: The following rule assumes that the 'ld' rule puts LDFLAGS before

#          the list of dependencies to form '-T $(obj)/hyp.lds'. This is to

#          keep the dependency on the target while avoiding an error from

#          GNU ld if the linker script is passed to it twice.

LDFLAGS_kvm_nvhe.tmp.o := -r -T

$(obj)/kvm_nvhe.tmp.o: $(obj)/hyp.lds $(addprefix $(obj)/,$(hyp-obj)) FORCE

	$(call if_changed,ld)

# 4) Produce the final 'kvm_nvhe.o', ready to be linked into 'vmlinux'.

#    Prefixes names of ELF symbols with '__kvm_nvhe_'.

$(obj)/kvm_nvhe.o: $(obj)/kvm_nvhe.tmp.o FORCE

	$(call if_changed,hypcopy)

# The HYPCOPY command uses `objcopy` to prefix all ELF symbol names

# and relevant ELF section names to avoid clashes with VHE code/data.

#

# Hyp code is assumed to be in the '.text' section of the input object

# files (with the exception of specialized sections such as

# '.hyp.idmap.text'). This assumption may be broken by a compiler that

# divides code into sections like '.text.unlikely' so as to optimize

# ELF layout. HYPCOPY checks that no such sections exist in the input

# using `objdump`, otherwise they would be linked together with other

# kernel code and not memory-mapped correctly at runtime.

# to avoid clashes with VHE code/data.

quiet_cmd_hypcopy = HYPCOPY $@

      cmd_hypcopy =							\

	if $(OBJDUMP) -h $< | grep -F '.text.'; then			\

		echo "$@: function reordering not supported in nVHE hyp code" >&2; \

		/bin/false;						\

	fi;								\

	$(OBJCOPY) --prefix-symbols=__kvm_nvhe_				\

		   --rename-section=.text=.hyp.text			\

		   $< $@

      cmd_hypcopy = $(OBJCOPY) --prefix-symbols=__kvm_nvhe_ $< $@

# Remove ftrace and Shadow Call Stack CFLAGS.

# This is equivalent to the 'notrace' and '__noscs' annotations.

/* SPDX-License-Identifier: GPL-2.0 */

/*

 * Copyright (C) 2020 Google LLC.

 * Written by David Brazdil <dbrazdil@google.com>

 *

 * Linker script used for partial linking of nVHE EL2 object files.

 */

#include <asm/hyp_image.h>

SECTIONS {

	HYP_SECTION(.text)

}