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69114be15b
Place -fcall-used* flags behind cc-option so that clang (which doesn't support them) can still compile the kernel. This is a safe change, the reasoning is as follows: In the (normal) 32-bit ABI, %g5 and %g7 is normally reserved, and in the 64-bit ABI, %g7 is the reserved one. Linux turns them into volatile registers by the way of -fcall-used-*, but on the other hand, omitting the flags shouldn't be harmful; compilers will now simply refuse to touch them, and any assembly code that happens to touch them would still work like usual (because Linux' conventions already treats them as volatile anyway). Signed-off-by: Koakuma <koachan@protonmail.com> Reviewed-by: Nathan Chancellor <nathan@kernel.org> Tested-by: Nathan Chancellor <nathan@kernel.org> Reviewed-by: Andreas Larsson <andreas@gaisler.com> Link: https://lore.kernel.org/r/20241029-sparc-cflags-v3-1-b28745a6bd71@protonmail.com Signed-off-by: Andreas Larsson <andreas@gaisler.com>
108 lines
3.5 KiB
Makefile
108 lines
3.5 KiB
Makefile
# SPDX-License-Identifier: GPL-2.0-only
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#
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# Building vDSO images for sparc.
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#
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# files to link into the vdso
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vobjs-y := vdso-note.o vclock_gettime.o
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# files to link into kernel
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obj-y += vma.o
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# vDSO images to build
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obj-$(CONFIG_SPARC64) += vdso-image-64.o
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obj-$(CONFIG_COMPAT) += vdso-image-32.o
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vobjs := $(addprefix $(obj)/, $(vobjs-y))
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$(obj)/vdso.o: $(obj)/vdso.so
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targets += vdso.lds $(vobjs-y)
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targets += $(foreach x, 32 64, vdso-image-$(x).c vdso$(x).so vdso$(x).so.dbg)
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CPPFLAGS_vdso.lds += -P -C
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VDSO_LDFLAGS_vdso.lds = -m elf64_sparc -soname linux-vdso.so.1 --no-undefined \
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-z max-page-size=8192
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$(obj)/vdso64.so.dbg: $(obj)/vdso.lds $(vobjs) FORCE
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$(call if_changed,vdso)
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HOST_EXTRACFLAGS += -I$(srctree)/tools/include
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hostprogs += vdso2c
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quiet_cmd_vdso2c = VDSO2C $@
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cmd_vdso2c = $(obj)/vdso2c $< $(<:%.dbg=%) $@
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$(obj)/vdso-image-%.c: $(obj)/vdso%.so.dbg $(obj)/vdso%.so $(obj)/vdso2c FORCE
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$(call if_changed,vdso2c)
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#
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# Don't omit frame pointers for ease of userspace debugging, but do
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# optimize sibling calls.
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#
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CFL := $(PROFILING) -mcmodel=medlow -fPIC -O2 -fasynchronous-unwind-tables -m64 \
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$(filter -g%,$(KBUILD_CFLAGS)) -fno-stack-protector \
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-fno-omit-frame-pointer -foptimize-sibling-calls \
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-DDISABLE_BRANCH_PROFILING -DBUILD_VDSO
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SPARC_REG_CFLAGS = -ffixed-g4 -ffixed-g5 $(call cc-option,-fcall-used-g5) $(call cc-option,-fcall-used-g7)
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$(vobjs): KBUILD_CFLAGS := $(filter-out $(RANDSTRUCT_CFLAGS) $(GCC_PLUGINS_CFLAGS) $(SPARC_REG_CFLAGS),$(KBUILD_CFLAGS)) $(CFL)
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#
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# vDSO code runs in userspace and -pg doesn't help with profiling anyway.
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#
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CFLAGS_REMOVE_vclock_gettime.o = -pg
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CFLAGS_REMOVE_vdso32/vclock_gettime.o = -pg
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$(obj)/%.so: OBJCOPYFLAGS := -S
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$(obj)/%.so: $(obj)/%.so.dbg FORCE
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$(call if_changed,objcopy)
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CPPFLAGS_vdso32/vdso32.lds = $(CPPFLAGS_vdso.lds)
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VDSO_LDFLAGS_vdso32.lds = -m elf32_sparc -soname linux-gate.so.1
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#This makes sure the $(obj) subdirectory exists even though vdso32/
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#is not a kbuild sub-make subdirectory
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override obj-dirs = $(dir $(obj)) $(obj)/vdso32/
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targets += vdso32/vdso32.lds
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targets += vdso32/vdso-note.o
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targets += vdso32/vclock_gettime.o
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KBUILD_AFLAGS_32 := $(filter-out -m64,$(KBUILD_AFLAGS)) -DBUILD_VDSO
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$(obj)/vdso32.so.dbg: KBUILD_AFLAGS = $(KBUILD_AFLAGS_32)
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$(obj)/vdso32.so.dbg: asflags-$(CONFIG_SPARC64) += -m32
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KBUILD_CFLAGS_32 := $(filter-out -m64,$(KBUILD_CFLAGS))
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KBUILD_CFLAGS_32 := $(filter-out -mcmodel=medlow,$(KBUILD_CFLAGS_32))
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KBUILD_CFLAGS_32 := $(filter-out -fno-pic,$(KBUILD_CFLAGS_32))
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KBUILD_CFLAGS_32 := $(filter-out $(RANDSTRUCT_CFLAGS),$(KBUILD_CFLAGS_32))
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KBUILD_CFLAGS_32 := $(filter-out $(GCC_PLUGINS_CFLAGS),$(KBUILD_CFLAGS_32))
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KBUILD_CFLAGS_32 := $(filter-out $(SPARC_REG_CFLAGS),$(KBUILD_CFLAGS_32))
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KBUILD_CFLAGS_32 += -m32 -msoft-float -fpic
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KBUILD_CFLAGS_32 += -fno-stack-protector
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KBUILD_CFLAGS_32 += $(call cc-option, -foptimize-sibling-calls)
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KBUILD_CFLAGS_32 += -fno-omit-frame-pointer
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KBUILD_CFLAGS_32 += -DDISABLE_BRANCH_PROFILING
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KBUILD_CFLAGS_32 += -mv8plus
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$(obj)/vdso32.so.dbg: KBUILD_CFLAGS = $(KBUILD_CFLAGS_32)
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$(obj)/vdso32.so.dbg: FORCE \
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$(obj)/vdso32/vdso32.lds \
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$(obj)/vdso32/vclock_gettime.o \
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$(obj)/vdso32/vdso-note.o
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$(call if_changed,vdso)
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#
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# The DSO images are built using a special linker script.
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#
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quiet_cmd_vdso = VDSO $@
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cmd_vdso = $(LD) -nostdlib -o $@ \
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$(VDSO_LDFLAGS) $(VDSO_LDFLAGS_$(filter %.lds,$(^F))) \
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-T $(filter %.lds,$^) $(filter %.o,$^) && \
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sh $(src)/checkundef.sh '$(OBJDUMP)' '$@'
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VDSO_LDFLAGS = -shared --hash-style=both --build-id=sha1 -Bsymbolic
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