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After commit73cdf24e81("powerpc64: make clang cross-build friendly"), building 64-bit little endian + CONFIG_COMPAT=y with clang results in many warnings along the lines of: $ cat arch/powerpc/configs/compat.config CONFIG_COMPAT=y $ make -skj"$(nproc)" ARCH=powerpc LLVM=1 ppc64le_defconfig compat.config arch/powerpc/kernel/vdso/ ... In file included from <built-in>:4: In file included from lib/vdso/gettimeofday.c:6: In file included from include/vdso/datapage.h:15: In file included from include/vdso/cache.h:5: arch/powerpc/include/asm/cache.h:77:8: warning: unknown attribute 'patchable_function_entry' ignored [-Wunknown-attributes] 77 | static inline u32 l1_icache_bytes(void) | ^~~~~~ include/linux/compiler_types.h:235:58: note: expanded from macro 'inline' 235 | #define inline inline __gnu_inline __inline_maybe_unused notrace | ^~~~~~~ include/linux/compiler_types.h:215:34: note: expanded from macro 'notrace' 215 | #define notrace __attribute__((patchable_function_entry(0, 0))) | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ... arch/powerpc/Makefile adds -DCC_USING_PATCHABLE_FUNCTION_ENTRY to KBUILD_CPPFLAGS, which is inherited by the 32-bit vDSO. However, the 32-bit little endian target does not support '-fpatchable-function-entry', resulting in the warnings above. Remove -DCC_USING_PATCHABLE_FUNCTION_ENTRY from the 32-bit vDSO flags when building with clang to avoid the warnings. Fixes:73cdf24e81("powerpc64: make clang cross-build friendly") Signed-off-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Madhavan Srinivasan <maddy@linux.ibm.com> Link: https://patch.msgid.link/20260311-ppc-vdso-drop-cc-using-pfe-define-clang-v1-1-66c790e22650@kernel.org
130 lines
5.5 KiB
Makefile
130 lines
5.5 KiB
Makefile
# SPDX-License-Identifier: GPL-2.0
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# List of files in the vdso, has to be asm only for now
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# Include the generic Makefile to check the built vdso.
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include $(srctree)/lib/vdso/Makefile.include
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obj-vdso32 = sigtramp32-32.o gettimeofday-32.o datapage-32.o cacheflush-32.o note-32.o getcpu-32.o
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obj-vdso64 = sigtramp64-64.o gettimeofday-64.o datapage-64.o cacheflush-64.o note-64.o getcpu-64.o
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obj-vdso32 += getrandom-32.o vgetrandom-chacha-32.o
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obj-vdso64 += getrandom-64.o vgetrandom-chacha-64.o
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ifneq ($(c-gettimeofday-y),)
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CFLAGS_vgettimeofday-32.o += -include $(c-gettimeofday-y)
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# Go prior to 1.16.x assumes r30 is not clobbered by any VDSO code. That used to be true
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# by accident when the VDSO was hand-written asm code, but may not be now that the VDSO is
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# compiler generated. To avoid breaking Go tell GCC not to use r30. Impact on code
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# generation is minimal, it will just use r29 instead.
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CFLAGS_vgettimeofday-64.o += -include $(c-gettimeofday-y) $(call cc-option, -ffixed-r30)
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endif
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ifneq ($(c-getrandom-y),)
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CFLAGS_vgetrandom-32.o += -include $(c-getrandom-y)
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CFLAGS_vgetrandom-64.o += -include $(c-getrandom-y)
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endif
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# Build rules
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ifdef CROSS32_COMPILE
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VDSOCC := $(CROSS32_COMPILE)gcc
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else
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VDSOCC := $(CC)
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endif
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targets := $(obj-vdso32) vdso32.so.dbg vgettimeofday-32.o vgetrandom-32.o
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targets += crtsavres-32.o
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obj-vdso32 := $(addprefix $(obj)/, $(obj-vdso32))
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targets += $(obj-vdso64) vdso64.so.dbg vgettimeofday-64.o vgetrandom-64.o
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obj-vdso64 := $(addprefix $(obj)/, $(obj-vdso64))
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ccflags-y := -fno-common -fno-builtin -DBUILD_VDSO
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ccflags-y += $(DISABLE_LATENT_ENTROPY_PLUGIN)
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ccflags-y += $(call cc-option, -fno-stack-protector)
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ccflags-y += -DDISABLE_BRANCH_PROFILING
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ccflags-y += -ffreestanding -fasynchronous-unwind-tables
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ccflags-remove-y := $(CC_FLAGS_FTRACE)
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ldflags-y := -Wl,--hash-style=both -nostdlib -shared -z noexecstack $(CLANG_FLAGS)
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ldflags-$(CONFIG_LD_IS_LLD) += $(call cc-option,--ld-path=$(LD),-fuse-ld=lld)
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ldflags-$(CONFIG_LD_ORPHAN_WARN) += -Wl,--orphan-handling=$(CONFIG_LD_ORPHAN_WARN_LEVEL)
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# Filter flags that clang will warn are unused for linking
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ldflags-y += $(filter-out $(CC_AUTO_VAR_INIT_ZERO_ENABLER) $(CC_FLAGS_FTRACE) -Wa$(comma)%, $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS))
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CC32FLAGS := -m32
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CC32FLAGSREMOVE := -mcmodel=medium -mabi=elfv1 -mabi=elfv2 -mcall-aixdesc -mpcrel
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ifdef CONFIG_CC_IS_CLANG
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# This flag is supported by clang for 64-bit but not 32-bit so it will cause
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# an unused command line flag warning for this file.
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CC32FLAGSREMOVE += -fno-stack-clash-protection
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# -mstack-protector-guard values from the 64-bit build are not valid for the
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# 32-bit one. clang validates the values passed to these arguments during
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# parsing, even when -fno-stack-protector is passed afterwards.
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CC32FLAGSREMOVE += -mstack-protector-guard%
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# ftrace is disabled for the vdso but arch/powerpc/Makefile adds this define to
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# KBUILD_CPPFLAGS, which enables use of the 'patchable_function_entry'
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# attribute in the 'inline' define via 'notrace'. This attribute is not
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# supported for the powerpcle target, resulting in many instances of
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# -Wunknown-attributes.
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CC32FLAGSREMOVE += -DCC_USING_PATCHABLE_FUNCTION_ENTRY
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endif
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LD32FLAGS := -Wl,-soname=linux-vdso32.so.1
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AS32FLAGS := -D__VDSO32__
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LD64FLAGS := -Wl,-soname=linux-vdso64.so.1
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AS64FLAGS := -D__VDSO64__
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targets += vdso32.lds
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CPPFLAGS_vdso32.lds += -P -C -Upowerpc
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targets += vdso64.lds
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CPPFLAGS_vdso64.lds += -P -C
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# link rule for the .so file, .lds has to be first
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$(obj)/vdso32.so.dbg: $(obj)/vdso32.lds $(obj-vdso32) $(obj)/vgettimeofday-32.o $(obj)/vgetrandom-32.o $(obj)/crtsavres-32.o FORCE
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$(call if_changed,vdso32ld_and_check)
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$(obj)/vdso64.so.dbg: $(obj)/vdso64.lds $(obj-vdso64) $(obj)/vgettimeofday-64.o $(obj)/vgetrandom-64.o FORCE
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$(call if_changed,vdso64ld_and_check)
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# assembly rules for the .S files
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$(obj-vdso32): %-32.o: %.S FORCE
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$(call if_changed_dep,vdso32as)
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$(obj)/crtsavres-32.o: %-32.o: $(srctree)/arch/powerpc/lib/crtsavres.S FORCE
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$(call if_changed_dep,vdso32as)
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$(obj)/vgettimeofday-32.o: %-32.o: %.c FORCE
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$(call if_changed_dep,vdso32cc)
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$(obj)/vgetrandom-32.o: %-32.o: %.c FORCE
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$(call if_changed_dep,vdso32cc)
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$(obj-vdso64): %-64.o: %.S FORCE
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$(call if_changed_dep,vdso64as)
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$(obj)/vgettimeofday-64.o: %-64.o: %.c FORCE
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$(call if_changed_dep,cc_o_c)
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$(obj)/vgetrandom-64.o: %-64.o: %.c FORCE
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$(call if_changed_dep,cc_o_c)
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# Generate VDSO offsets using helper script
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gen-vdso32sym := $(src)/gen_vdso32_offsets.sh
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quiet_cmd_vdso32sym = VDSO32SYM $@
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cmd_vdso32sym = $(NM) $< | $(gen-vdso32sym) | LC_ALL=C sort > $@
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gen-vdso64sym := $(src)/gen_vdso64_offsets.sh
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quiet_cmd_vdso64sym = VDSO64SYM $@
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cmd_vdso64sym = $(NM) $< | $(gen-vdso64sym) | LC_ALL=C sort > $@
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include/generated/vdso32-offsets.h: $(obj)/vdso32.so.dbg FORCE
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$(call if_changed,vdso32sym)
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include/generated/vdso64-offsets.h: $(obj)/vdso64.so.dbg FORCE
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$(call if_changed,vdso64sym)
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# actual build commands
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quiet_cmd_vdso32ld_and_check = VDSO32L $@
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cmd_vdso32ld_and_check = $(VDSOCC) $(ldflags-y) $(CC32FLAGS) $(LD32FLAGS) -o $@ -Wl,-T$(filter %.lds,$^) $(filter %.o,$^); $(cmd_vdso_check)
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quiet_cmd_vdso32as = VDSO32A $@
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cmd_vdso32as = $(VDSOCC) $(a_flags) $(CC32FLAGS) $(AS32FLAGS) -c -o $@ $<
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quiet_cmd_vdso32cc = VDSO32C $@
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cmd_vdso32cc = $(VDSOCC) $(filter-out $(CC32FLAGSREMOVE), $(c_flags)) $(CC32FLAGS) -c -o $@ $<
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quiet_cmd_vdso64ld_and_check = VDSO64L $@
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cmd_vdso64ld_and_check = $(VDSOCC) $(ldflags-y) $(LD64FLAGS) -o $@ -Wl,-T$(filter %.lds,$^) $(filter %.o,$^); $(cmd_vdso_check)
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quiet_cmd_vdso64as = VDSO64A $@
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cmd_vdso64as = $(VDSOCC) $(a_flags) $(AS64FLAGS) -c -o $@ $<
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