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4d94f910e7
The kernel is moving from using `-std=gnu89` to `-std=gnu11`, permitting the use of additional C11 features such as for-loop initial declarations. One contentious aspect of C99 is that it permits mixed declarations and code, and for now at least, it seems preferable to enforce that declarations must come first. These warnings were already enabled in the kernel itself, but not for KBUILD_USERCFLAGS or the compat VDSO on arch/arm64, which uses a separate set of CFLAGS. This patch fixes an existing violation in modpost.c, which is not reported because of the missing flag in KBUILD_USERCFLAGS: | scripts/mod/modpost.c: In function ‘match’: | scripts/mod/modpost.c:837:3: warning: ISO C90 forbids mixed declarations and code [-Wdeclaration-after-statement] | 837 | const char *endp = p + strlen(p) - 1; | | ^~~~~ Signed-off-by: Mark Rutland <mark.rutland@arm.com> [arnd: don't add a duplicate flag to the default set, update changelog] Signed-off-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Nathan Chancellor <nathan@kernel.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Tested-by: Sedat Dilek <sedat.dilek@gmail.com> # LLVM/Clang v13.0.0 (x86-64) Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
192 lines
6.6 KiB
Makefile
192 lines
6.6 KiB
Makefile
# SPDX-License-Identifier: GPL-2.0
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#
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# Makefile for vdso32
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#
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# Absolute relocation type $(ARCH_REL_TYPE_ABS) needs to be defined before
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# the inclusion of generic Makefile.
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ARCH_REL_TYPE_ABS := R_ARM_JUMP_SLOT|R_ARM_GLOB_DAT|R_ARM_ABS32
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include $(srctree)/lib/vdso/Makefile
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# Same as cc-*option, but using CC_COMPAT instead of CC
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ifeq ($(CONFIG_CC_IS_CLANG), y)
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CC_COMPAT ?= $(CC)
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CC_COMPAT += --target=arm-linux-gnueabi
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else
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CC_COMPAT ?= $(CROSS_COMPILE_COMPAT)gcc
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endif
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ifeq ($(CONFIG_LD_IS_LLD), y)
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LD_COMPAT ?= $(LD)
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else
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LD_COMPAT ?= $(CROSS_COMPILE_COMPAT)ld
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endif
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cc32-option = $(call try-run,\
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$(CC_COMPAT) $(1) -c -x c /dev/null -o "$$TMP",$(1),$(2))
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cc32-disable-warning = $(call try-run,\
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$(CC_COMPAT) -W$(strip $(1)) -c -x c /dev/null -o "$$TMP",-Wno-$(strip $(1)))
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# We cannot use the global flags to compile the vDSO files, the main reason
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# being that the 32-bit compiler may be older than the main (64-bit) compiler
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# and therefore may not understand flags set using $(cc-option ...). Besides,
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# arch-specific options should be taken from the arm Makefile instead of the
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# arm64 one.
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# As a result we set our own flags here.
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# KBUILD_CPPFLAGS and NOSTDINC_FLAGS from top-level Makefile
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VDSO_CPPFLAGS := -DBUILD_VDSO -D__KERNEL__ -nostdinc
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VDSO_CPPFLAGS += -isystem $(shell $(CC_COMPAT) -print-file-name=include 2>/dev/null)
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VDSO_CPPFLAGS += $(LINUXINCLUDE)
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# Common C and assembly flags
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# From top-level Makefile
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VDSO_CAFLAGS := $(VDSO_CPPFLAGS)
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VDSO_CAFLAGS += $(call cc32-option,-fno-PIE)
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ifdef CONFIG_DEBUG_INFO
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VDSO_CAFLAGS += -g
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endif
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# From arm Makefile
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VDSO_CAFLAGS += $(call cc32-option,-fno-dwarf2-cfi-asm)
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VDSO_CAFLAGS += -mabi=aapcs-linux -mfloat-abi=soft
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ifeq ($(CONFIG_CPU_BIG_ENDIAN), y)
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VDSO_CAFLAGS += -mbig-endian
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else
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VDSO_CAFLAGS += -mlittle-endian
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endif
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# From arm vDSO Makefile
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VDSO_CAFLAGS += -fPIC -fno-builtin -fno-stack-protector
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VDSO_CAFLAGS += -DDISABLE_BRANCH_PROFILING
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VDSO_CAFLAGS += -march=armv8-a
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VDSO_CFLAGS := $(VDSO_CAFLAGS)
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VDSO_CFLAGS += -DENABLE_COMPAT_VDSO=1
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# KBUILD_CFLAGS from top-level Makefile
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VDSO_CFLAGS += -Wall -Wundef -Wstrict-prototypes -Wno-trigraphs \
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-fno-strict-aliasing -fno-common \
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-Werror-implicit-function-declaration \
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-Wno-format-security \
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-Wdeclaration-after-statement \
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-std=gnu89
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VDSO_CFLAGS += -O2
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# Some useful compiler-dependent flags from top-level Makefile
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VDSO_CFLAGS += $(call cc32-option,-Wdeclaration-after-statement,)
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VDSO_CFLAGS += $(call cc32-option,-Wno-pointer-sign)
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VDSO_CFLAGS += -fno-strict-overflow
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VDSO_CFLAGS += $(call cc32-option,-Werror=strict-prototypes)
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VDSO_CFLAGS += -Werror=date-time
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VDSO_CFLAGS += $(call cc32-option,-Werror=incompatible-pointer-types)
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# The 32-bit compiler does not provide 128-bit integers, which are used in
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# some headers that are indirectly included from the vDSO code.
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# This hack makes the compiler happy and should trigger a warning/error if
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# variables of such type are referenced.
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VDSO_CFLAGS += -D__uint128_t='void*'
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# Silence some warnings coming from headers that operate on long's
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# (on GCC 4.8 or older, there is unfortunately no way to silence this warning)
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VDSO_CFLAGS += $(call cc32-disable-warning,shift-count-overflow)
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VDSO_CFLAGS += -Wno-int-to-pointer-cast
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# Compile as THUMB2 or ARM. Unwinding via frame-pointers in THUMB2 is
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# unreliable.
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ifeq ($(CONFIG_THUMB2_COMPAT_VDSO), y)
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VDSO_CFLAGS += -mthumb -fomit-frame-pointer
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else
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VDSO_CFLAGS += -marm
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endif
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VDSO_AFLAGS := $(VDSO_CAFLAGS)
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VDSO_AFLAGS += -D__ASSEMBLY__
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# From arm vDSO Makefile
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VDSO_LDFLAGS += -Bsymbolic --no-undefined -soname=linux-vdso.so.1
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VDSO_LDFLAGS += -z max-page-size=4096 -z common-page-size=4096
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VDSO_LDFLAGS += -shared --hash-style=sysv --build-id=sha1
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# Borrow vdsomunge.c from the arm vDSO
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# We have to use a relative path because scripts/Makefile.host prefixes
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# $(hostprogs) with $(obj)
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munge := ../../../arm/vdso/vdsomunge
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hostprogs := $(munge)
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c-obj-vdso := note.o
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c-obj-vdso-gettimeofday := vgettimeofday.o
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ifneq ($(c-gettimeofday-y),)
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VDSO_CFLAGS_gettimeofday_o += -include $(c-gettimeofday-y)
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endif
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VDSO_CFLAGS_REMOVE_vgettimeofday.o = $(CC_FLAGS_FTRACE) -Os
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# Build rules
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targets := $(c-obj-vdso) $(c-obj-vdso-gettimeofday) $(asm-obj-vdso) vdso.so vdso.so.dbg vdso.so.raw
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c-obj-vdso := $(addprefix $(obj)/, $(c-obj-vdso))
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c-obj-vdso-gettimeofday := $(addprefix $(obj)/, $(c-obj-vdso-gettimeofday))
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asm-obj-vdso := $(addprefix $(obj)/, $(asm-obj-vdso))
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obj-vdso := $(c-obj-vdso) $(c-obj-vdso-gettimeofday) $(asm-obj-vdso)
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targets += vdso.lds
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CPPFLAGS_vdso.lds += -P -C -U$(ARCH)
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# Force dependency (vdso.s includes vdso.so through incbin)
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$(obj)/vdso.o: $(obj)/vdso.so
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include/generated/vdso32-offsets.h: $(obj)/vdso.so.dbg FORCE
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$(call if_changed,vdsosym)
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# Strip rule for vdso.so
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$(obj)/vdso.so: OBJCOPYFLAGS := -S
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$(obj)/vdso.so: $(obj)/vdso.so.dbg FORCE
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$(call if_changed,objcopy)
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$(obj)/vdso.so.dbg: $(obj)/vdso.so.raw $(obj)/$(munge) FORCE
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$(call if_changed,vdsomunge)
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# Link rule for the .so file, .lds has to be first
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$(obj)/vdso.so.raw: $(src)/vdso.lds $(obj-vdso) FORCE
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$(call if_changed,vdsold_and_vdso_check)
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# Compilation rules for the vDSO sources
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$(c-obj-vdso): %.o: %.c FORCE
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$(call if_changed_dep,vdsocc)
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$(c-obj-vdso-gettimeofday): %.o: %.c FORCE
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$(call if_changed_dep,vdsocc_gettimeofday)
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$(asm-obj-vdso): %.o: %.S FORCE
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$(call if_changed_dep,vdsoas)
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# Actual build commands
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quiet_cmd_vdsold_and_vdso_check = LD32 $@
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cmd_vdsold_and_vdso_check = $(cmd_vdsold); $(cmd_vdso_check)
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quiet_cmd_vdsold = LD32 $@
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cmd_vdsold = $(LD_COMPAT) $(VDSO_LDFLAGS) \
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-T $(filter %.lds,$^) $(filter %.o,$^) -o $@
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quiet_cmd_vdsocc = CC32 $@
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cmd_vdsocc = $(CC_COMPAT) -Wp,-MD,$(depfile) $(VDSO_CFLAGS) -c -o $@ $<
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quiet_cmd_vdsocc_gettimeofday = CC32 $@
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cmd_vdsocc_gettimeofday = $(CC_COMPAT) -Wp,-MD,$(depfile) $(VDSO_CFLAGS) $(VDSO_CFLAGS_gettimeofday_o) -c -o $@ $<
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quiet_cmd_vdsoas = AS32 $@
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cmd_vdsoas = $(CC_COMPAT) -Wp,-MD,$(depfile) $(VDSO_AFLAGS) -c -o $@ $<
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quiet_cmd_vdsomunge = MUNGE $@
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cmd_vdsomunge = $(obj)/$(munge) $< $@
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# Generate vDSO offsets using helper script (borrowed from the 64-bit vDSO)
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gen-vdsosym := $(srctree)/$(src)/../vdso/gen_vdso_offsets.sh
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quiet_cmd_vdsosym = VDSOSYM $@
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# The AArch64 nm should be able to read an AArch32 binary
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cmd_vdsosym = $(NM) $< | $(gen-vdsosym) | LC_ALL=C sort > $@
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# Install commands for the unstripped file
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quiet_cmd_vdso_install = INSTALL32 $@
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cmd_vdso_install = cp $(obj)/$@.dbg $(MODLIB)/vdso/vdso32.so
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vdso.so: $(obj)/vdso.so.dbg
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@mkdir -p $(MODLIB)/vdso
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$(call cmd,vdso_install)
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vdso_install: vdso.so
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