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4938c79bd0
If you use a 64-bit compiler to build a 32-bit kernel then you'll get an error when building the vDSO due to a library mismatch. The happens because the relevant "-march" argument isn't supplied to the GCC run that generates one of the vDSO intermediate files. I'm not actually sure what the right thing to do here is as I'm not particularly familiar with the kernel build system. I poked the documentation and it appears that KCFLAGS is the correct thing to do (it's suggested that should be used when building modules), but we set KBUILD_CFLAGS in arch/riscv/Makefile. This does at least fix the build error. Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
68 lines
2.2 KiB
Makefile
68 lines
2.2 KiB
Makefile
# Copied from arch/tile/kernel/vdso/Makefile
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# Symbols present in the vdso
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vdso-syms = rt_sigreturn
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vdso-syms += gettimeofday
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vdso-syms += clock_gettime
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vdso-syms += clock_getres
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vdso-syms += getcpu
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vdso-syms += flush_icache
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# Files to link into the vdso
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obj-vdso = $(patsubst %, %.o, $(vdso-syms))
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# Build rules
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targets := $(obj-vdso) vdso.so vdso.so.dbg vdso.lds vdso-dummy.o
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obj-vdso := $(addprefix $(obj)/, $(obj-vdso))
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obj-y += vdso.o vdso-syms.o
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CPPFLAGS_vdso.lds += -P -C -U$(ARCH)
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# Disable gcov profiling for VDSO code
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GCOV_PROFILE := n
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# Force dependency
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$(obj)/vdso.o: $(obj)/vdso.so
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# link rule for the .so file, .lds has to be first
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SYSCFLAGS_vdso.so.dbg = $(c_flags)
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$(obj)/vdso.so.dbg: $(src)/vdso.lds $(obj-vdso) FORCE
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$(call if_changed,vdsold)
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# We also create a special relocatable object that should mirror the symbol
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# table and layout of the linked DSO. With ld -R we can then refer to
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# these symbols in the kernel code rather than hand-coded addresses.
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SYSCFLAGS_vdso.so.dbg = -shared -s -Wl,-soname=linux-vdso.so.1 \
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$(call cc-ldoption, -Wl$(comma)--hash-style=both)
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$(obj)/vdso-dummy.o: $(src)/vdso.lds $(obj)/rt_sigreturn.o FORCE
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$(call if_changed,vdsold)
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LDFLAGS_vdso-syms.o := -r -R
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$(obj)/vdso-syms.o: $(obj)/vdso-dummy.o FORCE
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$(call if_changed,ld)
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# strip rule for the .so file
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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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# actual build commands
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# The DSO images are built using a special linker script
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# Add -lgcc so rv32 gets static muldi3 and lshrdi3 definitions.
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# Make sure only to export the intended __vdso_xxx symbol offsets.
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quiet_cmd_vdsold = VDSOLD $@
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cmd_vdsold = $(CC) $(KBUILD_CFLAGS) $(call cc-option, -no-pie) -nostdlib -nostartfiles $(SYSCFLAGS_$(@F)) \
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-Wl,-T,$(filter-out FORCE,$^) -o $@.tmp && \
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$(CROSS_COMPILE)objcopy \
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$(patsubst %, -G __vdso_%, $(vdso-syms)) $@.tmp $@
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# install commands for the unstripped file
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quiet_cmd_vdso_install = INSTALL $@
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cmd_vdso_install = cp $(obj)/$@.dbg $(MODLIB)/vdso/$@
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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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