2017-06-23 19:02 GMT+09:00 Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx>:
> 2017-06-23 12:50 GMT+09:00 Nicholas Piggin <npiggin@xxxxxxxxx>:
>> On Fri, 23 Jun 2017 12:25:10 +0900
>> Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx> wrote:
>>
>>> 2017-06-22 21:39 GMT+09:00 Nicholas Piggin <npiggin@xxxxxxxxx>:
>>> > The VDSO symbols can't be linked into built-in.o when building with
>>> > thin archives, so change this to linking a new object file that is
>>> > included into the built-in.o.
>>> >
>>> > Cc: Yoshinori Sato <ysato@xxxxxxxxxxxxxxxxxxxx>
>>> > Cc: Rich Felker <dalias@xxxxxxxx>
>>> > Cc: linux-sh@xxxxxxxxxxxxxxx
>>> > Signed-off-by: Nicholas Piggin <npiggin@xxxxxxxxx>
>>> > ---
>>> > arch/sh/kernel/vsyscall/Makefile | 16 +++++++++-------
>>> > 1 file changed, 9 insertions(+), 7 deletions(-)
>>> >
>>> > diff --git a/arch/sh/kernel/vsyscall/Makefile b/arch/sh/kernel/vsyscall/Makefile
>>> > index 8f0ea5fc835c..efc7a6837ef6 100644
>>> > --- a/arch/sh/kernel/vsyscall/Makefile
>>> > +++ b/arch/sh/kernel/vsyscall/Makefile
>>> > @@ -1,4 +1,4 @@
>>> > -obj-y += vsyscall.o vsyscall-syscall.o
>>> > +obj-y += vsyscall.o vsyscall-syscall.o vsyscall-syms.o
>>> >
>>> > $(obj)/vsyscall-syscall.o: \
>>> > $(foreach F,trapa,$(obj)/vsyscall-$F.so)
>>> > @@ -26,11 +26,13 @@ $(obj)/vsyscall-%.so: $(src)/vsyscall.lds $(obj)/vsyscall-%.o FORCE
>>> > # We also create a special relocatable object that should mirror the symbol
>>> > # table and layout of the linked DSO. With ld -R we can then refer to
>>> > # these symbols in the kernel code rather than hand-coded addresses.
>>> > -extra-y += vsyscall-syms.o
>>> > -$(obj)/built-in.o: $(obj)/vsyscall-syms.o
>>> > -$(obj)/built-in.o: ld_flags += -R $(obj)/vsyscall-syms.o
>>> > -
>>> > -SYSCFLAGS_vsyscall-syms.o = -r
>>> > -$(obj)/vsyscall-syms.o: $(src)/vsyscall.lds \
>>> > +SYSCFLAGS_vsyscall-dummy.o = -r
>>> > +$(obj)/vsyscall-dummy.o: $(src)/vsyscall.lds \
>>> > $(obj)/vsyscall-trapa.o $(obj)/vsyscall-note.o FORCE
>>> > $(call if_changed,syscall)
>>> > +
>>> > +quiet_cmd_syscall_syms = SYSCALL $@
>>> > + cmd_syscall_syms = $(LD) -r -R $(obj)/vsyscall-dummy.o -o $@
>>> > +
>>> > +$(obj)/vsyscall-syms.o: $(obj)/vsyscall-dummy.o
>>> > + $(call if_changed,syscall_syms)
>>> > --
>>> > 2.11.0
>>>
>>> I applied this, but
>>> I just noticed vsyscall-dummy is rebuilt every time.
>>>
>>>
>>> SYSCALL arch/sh/kernel/vsyscall/vsyscall-dummy.o
>>> SYSCALL arch/sh/kernel/vsyscall/vsyscall-syms.o
>>> AR arch/sh/kernel/vsyscall/built-in.o
>>> AR arch/sh/kernel/built-in.o
>>>
>>>
>>>
>>> We can avoid the unneeded rebuild by adding "vsyscall-dummy.o" to "targets".
>>>
>>> targets += vsyscall-note.o vsyscall.lds vsyscall-dummy.o
>>
>> Thanks, good catch. The tile patch may have the same issue?
>> --
>
> I think so.
>
>
> One more fix.
>
>
> +$(obj)/vsyscall-syms.o: $(obj)/vsyscall-dummy.o
> + $(call if_changed,syscall_syms)
>
>
> $(call if_changed,...) must have FORCE in the dependency field.
> Otherwise, if_changed may not be evaluated.
>
> I can fix up it locally. :-)
>
I updated thin-ar branch.
Just in case, the following is my local fix-up:
- Fix incremental build
- Do not repeat "$(obj)/vsyscall-dummy.o" in the build command
diff --git a/arch/sh/kernel/vsyscall/Makefile b/arch/sh/kernel/vsyscall/Makefile
index efc7a68..99685e5 100644
--- a/arch/sh/kernel/vsyscall/Makefile
+++ b/arch/sh/kernel/vsyscall/Makefile
@@ -5,7 +5,7 @@ $(obj)/vsyscall-syscall.o: \
# Teach kbuild about targets
targets += $(foreach F,trapa,vsyscall-$F.o vsyscall-$F.so)
-targets += vsyscall-note.o vsyscall.lds
+targets += vsyscall-note.o vsyscall.lds vsyscall-dummy.o
# The DSO images are built using a special linker script
quiet_cmd_syscall = SYSCALL $@
@@ -32,7 +32,7 @@ $(obj)/vsyscall-dummy.o: $(src)/vsyscall.lds \
$(call if_changed,syscall)
quiet_cmd_syscall_syms = SYSCALL $@
- cmd_syscall_syms = $(LD) -r -R $(obj)/vsyscall-dummy.o -o $@
+ cmd_syscall_syms = $(LD) -r -o $@ -R $<
-$(obj)/vsyscall-syms.o: $(obj)/vsyscall-dummy.o
+$(obj)/vsyscall-syms.o: $(obj)/vsyscall-dummy.o FORCE
$(call if_changed,syscall_syms)
--
Best Regards
Masahiro Yamada
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