arch/arm64/kernel/vdso32/Makefile

Source file repositories/reference/linux-study-clean/arch/arm64/kernel/vdso32/Makefile

File Facts

System
Linux kernel
Corpus path
arch/arm64/kernel/vdso32/Makefile
Extension
[no extension]
Size
5115 bytes
Lines
154
Domain
Architecture Layer
Bucket
arch/arm64
Inferred role
Architecture Layer: build/configuration rule
Status
atlas-only

Why This File Exists

CPU and platform-specific kernel glue: boot entry, traps, syscall entry, interrupts, page tables, context switch, and low-level barriers.

Dependency Surface

Detected Declarations

Annotated Snippet

# SPDX-License-Identifier: GPL-2.0
#
# Makefile for vdso32
#

include $(srctree)/lib/vdso/Makefile.include

# Same as cc-*option, but using CC_COMPAT instead of CC
ifeq ($(CONFIG_CC_IS_CLANG), y)
CC_COMPAT ?= $(CC)
CC_COMPAT += --target=arm-linux-gnueabi
else
CC_COMPAT ?= $(CROSS_COMPILE_COMPAT)gcc
endif

ifeq ($(CONFIG_LD_IS_LLD), y)
LD_COMPAT ?= $(LD)
else
LD_COMPAT ?= $(CROSS_COMPILE_COMPAT)ld
endif

cc32-option = $(call try-run,\
        $(CC_COMPAT) $(1) -c -x c /dev/null -o "$$TMP",$(1),$(2))

# We cannot use the global flags to compile the vDSO files, the main reason
# being that the 32-bit compiler may be older than the main (64-bit) compiler
# and therefore may not understand flags set using $(cc-option ...). Besides,
# arch-specific options should be taken from the arm Makefile instead of the
# arm64 one.
# As a result we set our own flags here.

# KBUILD_CPPFLAGS and NOSTDINC_FLAGS from top-level Makefile
VDSO_CPPFLAGS := -DBUILD_VDSO -D__KERNEL__ -nostdinc
VDSO_CPPFLAGS += -isystem $(shell $(CC_COMPAT) -print-file-name=include 2>/dev/null)
VDSO_CPPFLAGS += $(LINUXINCLUDE)

# Common C and assembly flags
# From top-level Makefile
VDSO_CAFLAGS := $(VDSO_CPPFLAGS)
VDSO_CAFLAGS += $(call cc32-option,-fno-PIE)
ifdef CONFIG_DEBUG_INFO
VDSO_CAFLAGS += -g
endif

# From arm Makefile
VDSO_CAFLAGS += $(call cc32-option,-fno-dwarf2-cfi-asm)
VDSO_CAFLAGS += -mabi=aapcs-linux -mfloat-abi=soft
ifeq ($(CONFIG_CPU_BIG_ENDIAN), y)
VDSO_CAFLAGS += -mbig-endian
else
VDSO_CAFLAGS += -mlittle-endian
endif

# From arm vDSO Makefile
VDSO_CAFLAGS += -fPIC -fno-builtin -fno-stack-protector
VDSO_CAFLAGS += -DDISABLE_BRANCH_PROFILING
VDSO_CAFLAGS += -march=armv8-a

VDSO_CFLAGS := $(VDSO_CAFLAGS)
# KBUILD_CFLAGS from top-level Makefile
VDSO_CFLAGS += -Wall -Wundef -Wstrict-prototypes -Wno-trigraphs \
               -fno-strict-aliasing -fno-common \
               $(filter -Werror,$(KBUILD_CPPFLAGS)) \
               -Werror-implicit-function-declaration \
               -Wno-format-security \
               $(CC_FLAGS_DIALECT)
VDSO_CFLAGS  += -O2
# Some useful compiler-dependent flags from top-level Makefile
VDSO_CFLAGS += $(call cc32-option,-Wno-pointer-sign)
VDSO_CFLAGS += -fno-strict-overflow

Annotation

Implementation Notes