Relinking zImage when nothing changes

I was hoping with the recent patch e78e8f2 (kernel: prevent unnecessary rebuilding due to config_data.gz, 2011-07-05) compiling ARM linux a second time would amount to no more linking. This doesn't seem to be the case though. Doing a make V=2 I see that lib1funcs.S is shipped and thus we have to recompile it although nothing actually changed. This in turn requires us to relink the compressed vmlinux and then recreate the zImage.

Kernel: arch/arm/boot/Image is ready
SHIPPED arch/arm/boot/compressed/lib1funcs.S - due to missing .cmd file
AS arch/arm/boot/compressed/lib1funcs.o - due to: arch/arm/boot/compressed/lib1funcs.S
LD arch/arm/boot/compressed/vmlinux - due to: arch/arm/boot/compressed/lib1funcs.o
OBJCOPY arch/arm/boot/zImage - due to: arch/arm/boot/compressed/vmlinux
Kernel: arch/arm/boot/zImage is ready

Is there any way to avoid this? Perhaps the shipped command could become a bit wiser?

Quoted 15 lines · Stephen Boyd

I was hoping with the recent patch e78e8f2 (kernel: prevent unnecessary rebuilding due to config_data.gz, 2011-07-05) compiling ARM linux a second time would amount to no more linking. This doesn't seem to be the case though. Doing a make V=2 I see that lib1funcs.S is shipped and thus we have to recompile it although nothing actually changed. This in turn requires us to relink the compressed vmlinux and then recreate the zImage.

Kernel: arch/arm/boot/Image is ready
SHIPPED arch/arm/boot/compressed/lib1funcs.S - due to missing .cmd file
AS arch/arm/boot/compressed/lib1funcs.o - due to: arch/arm/boot/compressed/lib1funcs.S
LD arch/arm/boot/compressed/vmlinux - due to: arch/arm/boot/compressed/lib1funcs.o
OBJCOPY arch/arm/boot/zImage - due to: arch/arm/boot/compressed/vmlinux
Kernel: arch/arm/boot/zImage is ready

Quoted 2 lines

Is there any way to avoid this? Perhaps the shipped command could become a bit wiser?

Following patch will likely fix it:

arch/arm/boot/compressed/Makefile +1 -1

index 0c74a6f..80b6b6e 100644
@@ -123,7 +123,7 @@ LDFLAGS_vmlinux += -T
 # For __aeabi_uidivmod
 lib1funcs = $(obj)/lib1funcs.o
 
-$(obj)/lib1funcs.S: $(srctree)/arch/$(SRCARCH)/lib/lib1funcs.S FORCE
+$(obj)/lib1funcs.S: $(srctree)/arch/$(SRCARCH)/lib/lib1funcs.S
        $(call cmd,shipped)
 
 # We need to prevent any GOTOFF relocs being used with references

(cut'n'pasted ...)

The FORCE prerequisite will tell make to always execute the command. But we only want to execute the command if:
1) $(obj)/lib1funcs.S is missing
2) or $(srctree)/arch/$(SRCARCH)/lib/lib1funcs.S is not older then $(obj)/lib1funcs.S

So dropping FORCE should be a safe thing to do.

Quoted 33 lines · Sam Ravnborg

Quoted 15 lines · Stephen Boyd

I was hoping with the recent patch e78e8f2 (kernel: prevent unnecessary rebuilding due to config_data.gz, 2011-07-05) compiling ARM linux a second time would amount to no more linking. This doesn't seem to be the case though. Doing a make V=2 I see that lib1funcs.S is shipped and thus we have to recompile it although nothing actually changed. This in turn requires us to relink the compressed vmlinux and then recreate the zImage.

Kernel: arch/arm/boot/Image is ready
SHIPPED arch/arm/boot/compressed/lib1funcs.S - due to missing .cmd file
AS arch/arm/boot/compressed/lib1funcs.o - due to: arch/arm/boot/compressed/lib1funcs.S
LD arch/arm/boot/compressed/vmlinux - due to: arch/arm/boot/compressed/lib1funcs.o
OBJCOPY arch/arm/boot/zImage - due to: arch/arm/boot/compressed/vmlinux
Kernel: arch/arm/boot/zImage is ready

Quoted 2 lines

Is there any way to avoid this? Perhaps the shipped command could become a bit wiser?

Following patch will likely fix it:

arch/arm/boot/compressed/Makefile +1 -1

index 0c74a6f..80b6b6e 100644
@@ -123,7 +123,7 @@ LDFLAGS_vmlinux += -T
 # For __aeabi_uidivmod
 lib1funcs = $(obj)/lib1funcs.o
 
-$(obj)/lib1funcs.S: $(srctree)/arch/$(SRCARCH)/lib/lib1funcs.S FORCE
+$(obj)/lib1funcs.S: $(srctree)/arch/$(SRCARCH)/lib/lib1funcs.S
        $(call cmd,shipped)
 
 # We need to prevent any GOTOFF relocs being used with references

Quoted 9 lines

(cut'n'pasted ...)

The FORCE prerequisite will tell make to always execute the command. But we only want to execute the command if:
1) $(obj)/lib1funcs.S is missing
2) or $(srctree)/arch/$(SRCARCH)/lib/lib1funcs.S is not older then $(obj)/lib1funcs.S

So dropping FORCE should be a safe thing to do.

Hm... that fixes the shipped part. But now we still reassemble lib1funcs.o.

  Kernel: arch/arm/boot/Image is ready
  AS      arch/arm/boot/compressed/lib1funcs.o - due to lib1funcs.o not in $(targets)
  LD      arch/arm/boot/compressed/vmlinux - due to: arch/arm/boot/compressed/lib1funcs.o
  OBJCOPY arch/arm/boot/zImage - due to: arch/arm/boot/compressed/vmlinux
  Kernel: arch/arm/boot/zImage is ready

Is it correct to add lib1funcs.o to targets?

arch/arm/boot/compressed/Makefile +1 -1

index 0c74a6f..64889e6 100644
@@ -91,7 +91,7 @@ suffix_$(CONFIG_KERNEL_LZMA) = lzma
 
 targets       := vmlinux vmlinux.lds \
                 piggy.$(suffix_y) piggy.$(suffix_y).o \
-                font.o font.c head.o misc.o $(OBJS)
+                font.o font.c head.o misc.o lib1funcs.o $(OBJS)
 
 # Make sure files are removed during clean
 extra-y       += piggy.gzip piggy.lzo piggy.lzma lib1funcs.S

Quoted 10 lines · Stephen Boyd

Hm... that fixes the shipped part. But now we still reassemble lib1funcs.o.

  Kernel: arch/arm/boot/Image is ready
  AS      arch/arm/boot/compressed/lib1funcs.o - due to lib1funcs.o not in $(targets)
  LD      arch/arm/boot/compressed/vmlinux - due to: arch/arm/boot/compressed/lib1funcs.o
  OBJCOPY arch/arm/boot/zImage - due to: arch/arm/boot/compressed/vmlinux
  Kernel: arch/arm/boot/zImage is ready

Quoted 1 line

Is it correct to add lib1funcs.o to targets?

Yes - it is a bug this was not done before.

Quoted 3 lines

# For __aeabi_uidivmod
lib1funcs = $(obj)/lib1funcs.o

While touching the file I would kill this assignment - it confused me.

Quoted 6 lines

-$(obj)/lib1funcs.S: $(srctree)/arch/$(SRCARCH)/lib/lib1funcs.S FORCE +$(obj)/lib1funcs.S: $(srctree)/arch/$(SRCARCH)/lib/lib1funcs.S

        $(call cmd,shipped)

# We need to prevent any GOTOFF relocs being used with references

If you prepare a patch with the changes then you can add my "Acked-by".

lib1funcs.S is reshipped even though the file hasn't changed because the make rule is marked with FORCE. According to Sam Ravnborg:

? ? ? ?The FORCE prerequisite will tell make to always execute ? ? ? ?the command.
? ? ? ?But we only want to execute the command if:
? ? ? ?1) $(obj)/lib1funcs.S is missing
? ? ? ?2) or $(srctree)/arch/$(SRCARCH)/lib/lib1funcs.S is not ? ? ? ?older then $(obj)/lib1funcs.S

? ? ? ?So dropping FORCE should be a safe thing to do.

This fixes the shipped problem, but we still have to reassemble lib1funcs.S because it isn't part of $targets. Add lib1funcs.{S,o} to $targets to avoid relinking the compressed vmlinux if nothing changes.

Signed-off-by Stephen Boyd <[email protected]>

Acked-by Sam Ravnborg <[email protected]>

---
?arch/arm/boot/compressed/Makefile | ? ?8 +++----- ?1 files changed, 3 insertions(+), 5 deletions(-)

arch/arm/boot/compressed/Makefile +1 -1

index 0c74a6f..937fd26 100644
@@ -91,7 +91,7 @@ suffix_$(CONFIG_KERNEL_LZMA) = lzma
 
 ?targets ? ? ? := vmlinux vmlinux.lds \
 ? ? ? ? ? ? ? ? piggy.$(suffix_y) piggy.$(suffix_y).o \
- ? ? ? ? ? ? ? ?font.o font.c head.o misc.o $(OBJS)
+ ? ? ? ? ? ? ? ?font.o font.c head.o misc.o lib1funcs.o lib1funcs.S $(OBJS)
 

?# Make sure files are removed during clean ?extra-y ? ? ? += piggy.gzip piggy.lzo piggy.lzma lib1funcs.S

arch/arm/boot/compressed/Makefile +0 -0

@@ -121,9 +121,7 @@ LDFLAGS_vmlinux += -X

?LDFLAGS_vmlinux += -T

?# For __aeabi_uidivmod

arch/arm/boot/compressed/Makefile +1 -3

-lib1funcs = $(obj)/lib1funcs.o
-
-$(obj)/lib1funcs.S: $(srctree)/arch/$(SRCARCH)/lib/lib1funcs.S FORCE
+$(obj)/lib1funcs.S: $(srctree)/arch/$(SRCARCH)/lib/lib1funcs.S

? ? ? ?$(call cmd,shipped)

?# We need to prevent any GOTOFF relocs being used with references

arch/arm/boot/compressed/Makefile +1 -2

@@ -140,7 +138,7 @@ bad_syms=$$($(CROSS_COMPILE)nm $@ | sed -n 's/^.\{8\} [bc] \(.*\)/\1/p') && \
 ? ? echo "$$bad_syms" >&2; rm -f $@; false )
 
 ?$(obj)/vmlinux: $(obj)/vmlinux.lds $(obj)/$(HEAD) $(obj)/piggy.$(suffix_y).o \
- ? ? ? ? ? ? ? $(addprefix $(obj)/, $(OBJS)) $(lib1funcs) FORCE
+ ? ? ? ? ? ? ? $(addprefix $(obj)/, $(OBJS)) $(obj)/lib1funcs.o FORCE
 ? ? ? ?$(call if_changed,ld)
 ? ? ? ?@$(check_for_bad_syms)
 
--

Sent by an employee of the Qualcomm Innovation Center, Inc. The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum.

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You should be able to avoid the extra copy altogether by doing something ala:

$(obj)/lib1funcs.o: $(srctree)/arch/arm/lib/lib1funcs.S

        $(call cmd,as_o_S)

note that I also remove the $(SRCARCH), as there is no other arch/*/lib/lib1funcs.S' than arch/arm/lib/lib1funcs.S'

Quoted 5 lines · Arnaud Lacombe

You should be able to avoid the extra copy altogether by doing something ala:

$(obj)/lib1funcs.o: $(srctree)/arch/arm/lib/lib1funcs.S ? ? ? ? $(call cmd,as_o_S)

Quoted 2 lines

note that I also remove the $(SRCARCH), as there is no other arch/*/lib/lib1funcs.S' than arch/arm/lib/lib1funcs.S'

We tried such things, but it results in kbuild arguing over building lib1funcs.S in arch/arm/lib and arch/arm/boot/compressed. ?You end up with it rebuilding the arch/arm/lib one, followed by a rebuild of the arch/arm/boot/compressed one.

We've ended up with what we have because its about the only way to get kbuild to behave.

I suspect this would have done the job:

$(obj)/font.o: $(srctree)/drivers/video/console/font_acorn_8x8.c

        $(cmd,cc_o_c)'

Quoted 5 lines

I suspect this would have done the job:

$(obj)/font.o: $(srctree)/drivers/video/console/font_acorn_8x8.c ? ? ? ? $(cmd,cc_o_c)'

I prefer using $(call,shipped) and let kbuild figure out how build an .o file from a .c file.

In other words - avoiding use of the internal to Makefile.build variables in various places.

Hi,

Quoted 9 lines · Sam Ravnborg

Quoted 5 lines

I suspect this would have done the job:

$(obj)/font.o: $(srctree)/drivers/video/console/font_acorn_8x8.c ? ? ? ? $(cmd,cc_o_c)'

I prefer using $(call,shipped) and let kbuild figure out how build an .o file from a .c file.

Quoted 3 lines

In other words - avoiding use of the internal to Makefile.build variables in various places.

indeed, but I'd argue that 1) this would not be the first Makefile using these internal macros (alpha and ia64 are using such construct for aliasing) and 2) the `cmd_shipped' stuff is as internal than other functions :-)

Quoted 12 lines · Arnaud Lacombe

Hi,

Quoted 9 lines · Sam Ravnborg

Quoted 5 lines

I suspect this would have done the job:

$(obj)/font.o: $(srctree)/drivers/video/console/font_acorn_8x8.c ? ? ? ? $(cmd,cc_o_c)'

I prefer using $(call,shipped) and let kbuild figure out how build an .o file from a .c file.

Quoted 7 lines

Quoted 3 lines

In other words - avoiding use of the internal to Makefile.build variables in various places.

indeed, but I'd argue that 1) this would not be the first Makefile using these internal macros (alpha and ia64 are using such construct for aliasing) and 2) the `cmd_shipped' stuff is as internal than other functions :-)

A quick grep in Documentation/kbuild will show that only the shipped variant is documented.

We could implement a general copy command - this is needed in some places like this.

Hi,

Quoted 45 lines · Stephen Boyd

lib1funcs.S is reshipped even though the file hasn't changed because the make rule is marked with FORCE. According to Sam Ravnborg:

? ? ? ?The FORCE prerequisite will tell make to always execute ? ? ? ?the command.
? ? ? ?But we only want to execute the command if:
? ? ? ?1) $(obj)/lib1funcs.S is missing
? ? ? ?2) or $(srctree)/arch/$(SRCARCH)/lib/lib1funcs.S is not ? ? ? ?older then $(obj)/lib1funcs.S

? ? ? ?So dropping FORCE should be a safe thing to do.

This fixes the shipped problem, but we still have to reassemble lib1funcs.S because it isn't part of $targets. Add lib1funcs.{S,o} to $targets to avoid relinking the compressed vmlinux if nothing changes.

Signed-off-by Stephen Boyd <[email protected]>

Acked-by Sam Ravnborg <[email protected]>

---
?arch/arm/boot/compressed/Makefile | ? ?8 +++----- ?1 files changed, 3 insertions(+), 5 deletions(-)

arch/arm/boot/compressed/Makefile +1 -1

index 0c74a6f..937fd26 100644
@@ -91,7 +91,7 @@ suffix_$(CONFIG_KERNEL_LZMA) = lzma
 
 ?targets ? ? ? := vmlinux vmlinux.lds \
 ? ? ? ? ? ? ? ? piggy.$(suffix_y) piggy.$(suffix_y).o \
- ? ? ? ? ? ? ? ?font.o font.c head.o misc.o $(OBJS)
+ ? ? ? ? ? ? ? ?font.o font.c head.o misc.o lib1funcs.o lib1funcs.S $(OBJS)
 

?# Make sure files are removed during clean ?extra-y ? ? ? += piggy.gzip piggy.lzo piggy.lzma lib1funcs.S

arch/arm/boot/compressed/Makefile +0 -0

@@ -121,9 +121,7 @@ LDFLAGS_vmlinux += -X

?LDFLAGS_vmlinux += -T

?# For __aeabi_uidivmod

arch/arm/boot/compressed/Makefile +1 -3

-lib1funcs = $(obj)/lib1funcs.o
-
-$(obj)/lib1funcs.S: $(srctree)/arch/$(SRCARCH)/lib/lib1funcs.S FORCE
+$(obj)/lib1funcs.S: $(srctree)/arch/$(SRCARCH)/lib/lib1funcs.S

Quoted 2 lines

? ? ? ?$(call cmd,shipped)

You should be able to avoid the extra copy altogether by doing something ala:

$(obj)/lib1funcs.o: $(srctree)/arch/arm/lib/lib1funcs.S ? ? ? ?$(call cmd,as_o_S)

note that I also remove the $(SRCARCH), as there is no other arch/*/lib/lib1funcs.S' than arch/arm/lib/lib1funcs.S'

Quoted 19 lines

?# We need to prevent any GOTOFF relocs being used with references

arch/arm/boot/compressed/Makefile +1 -2

@@ -140,7 +138,7 @@ bad_syms=$$($(CROSS_COMPILE)nm $@ | sed -n 's/^.\{8\} [bc] \(.*\)/\1/p') && \
 ? ? echo "$$bad_syms" >&2; rm -f $@; false )
 
 ?$(obj)/vmlinux: $(obj)/vmlinux.lds $(obj)/$(HEAD) $(obj)/piggy.$(suffix_y).o \
- ? ? ? ? ? ? ? $(addprefix $(obj)/, $(OBJS)) $(lib1funcs) FORCE
+ ? ? ? ? ? ? ? $(addprefix $(obj)/, $(OBJS)) $(obj)/lib1funcs.o FORCE
 ? ? ? ?$(call if_changed,ld)
 ? ? ? ?@$(check_for_bad_syms)
 
--

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Quoted 29 lines · Arnaud Lacombe

Quoted 21 lines · Stephen Boyd

arch/arm/boot/compressed/Makefile +1 -1

index 0c74a6f..937fd26 100644
@@ -91,7 +91,7 @@ suffix_$(CONFIG_KERNEL_LZMA) = lzma
 
 ?targets ? ? ? := vmlinux vmlinux.lds \
 ? ? ? ? ? ? ? ? piggy.$(suffix_y) piggy.$(suffix_y).o \
- ? ? ? ? ? ? ? ?font.o font.c head.o misc.o $(OBJS)
+ ? ? ? ? ? ? ? ?font.o font.c head.o misc.o lib1funcs.o lib1funcs.S $(OBJS)
 

?# Make sure files are removed during clean ?extra-y ? ? ? += piggy.gzip piggy.lzo piggy.lzma lib1funcs.S

arch/arm/boot/compressed/Makefile +0 -0

@@ -121,9 +121,7 @@ LDFLAGS_vmlinux += -X

?LDFLAGS_vmlinux += -T

?# For __aeabi_uidivmod

arch/arm/boot/compressed/Makefile +1 -3

-lib1funcs = $(obj)/lib1funcs.o
-
-$(obj)/lib1funcs.S: $(srctree)/arch/$(SRCARCH)/lib/lib1funcs.S FORCE
+$(obj)/lib1funcs.S: $(srctree)/arch/$(SRCARCH)/lib/lib1funcs.S

Quoted 2 lines

? ? ? ?$(call cmd,shipped)

You should be able to avoid the extra copy altogether by doing something ala:

$(obj)/lib1funcs.o: $(srctree)/arch/arm/lib/lib1funcs.S ? ? ? ?$(call cmd,as_o_S)

Quoted 3 lines

note that I also remove the $(SRCARCH), as there is no other arch/*/lib/lib1funcs.S' than arch/arm/lib/lib1funcs.S'

I withdraw this proposal and will hack around this to find a proper solution from within kbuild, and eventually come back on these uses :-)

Quoted 33 lines · Arnaud Lacombe

Quoted 32 lines · Arnaud Lacombe

Quoted 21 lines · Stephen Boyd

arch/arm/boot/compressed/Makefile +1 -1

index 0c74a6f..937fd26 100644
@@ -91,7 +91,7 @@ suffix_$(CONFIG_KERNEL_LZMA) = lzma
 
 ?targets ? ? ? := vmlinux vmlinux.lds \
 ? ? ? ? ? ? ? ? piggy.$(suffix_y) piggy.$(suffix_y).o \
- ? ? ? ? ? ? ? ?font.o font.c head.o misc.o $(OBJS)
+ ? ? ? ? ? ? ? ?font.o font.c head.o misc.o lib1funcs.o lib1funcs.S $(OBJS)
 

?# Make sure files are removed during clean ?extra-y ? ? ? += piggy.gzip piggy.lzo piggy.lzma lib1funcs.S

arch/arm/boot/compressed/Makefile +0 -0

@@ -121,9 +121,7 @@ LDFLAGS_vmlinux += -X

?LDFLAGS_vmlinux += -T

?# For __aeabi_uidivmod

arch/arm/boot/compressed/Makefile +1 -3

-lib1funcs = $(obj)/lib1funcs.o
-
-$(obj)/lib1funcs.S: $(srctree)/arch/$(SRCARCH)/lib/lib1funcs.S FORCE
+$(obj)/lib1funcs.S: $(srctree)/arch/$(SRCARCH)/lib/lib1funcs.S

Quoted 2 lines

? ? ? ?$(call cmd,shipped)

You should be able to avoid the extra copy altogether by doing something ala:

$(obj)/lib1funcs.o: $(srctree)/arch/arm/lib/lib1funcs.S ? ? ? ?$(call cmd,as_o_S)

note that I also remove the $(SRCARCH), as there is no other arch/*/lib/lib1funcs.S' than arch/arm/lib/lib1funcs.S'

Quoted 3 lines

I withdraw this proposal and will hack around this to find a proper solution from within kbuild, and eventually come back on these uses :-)

Any progress on this?

I have a patch doing multiple similar $(call cmd,shipped) at the moment and this is far from looking nice.

Hi,

Quoted 40 lines · Nicolas Pitre

Quoted 30 lines · Arnaud Lacombe

Quoted 29 lines · Arnaud Lacombe

Quoted 21 lines · Stephen Boyd

arch/arm/boot/compressed/Makefile +1 -1

index 0c74a6f..937fd26 100644
@@ -91,7 +91,7 @@ suffix_$(CONFIG_KERNEL_LZMA) = lzma
 
 ?targets ? ? ? := vmlinux vmlinux.lds \
 ? ? ? ? ? ? ? ? piggy.$(suffix_y) piggy.$(suffix_y).o \
- ? ? ? ? ? ? ? ?font.o font.c head.o misc.o $(OBJS)
+ ? ? ? ? ? ? ? ?font.o font.c head.o misc.o lib1funcs.o lib1funcs.S $(OBJS)
 

?# Make sure files are removed during clean ?extra-y ? ? ? += piggy.gzip piggy.lzo piggy.lzma lib1funcs.S

arch/arm/boot/compressed/Makefile +0 -0

@@ -121,9 +121,7 @@ LDFLAGS_vmlinux += -X

?LDFLAGS_vmlinux += -T

?# For __aeabi_uidivmod

arch/arm/boot/compressed/Makefile +1 -3

-lib1funcs = $(obj)/lib1funcs.o
-
-$(obj)/lib1funcs.S: $(srctree)/arch/$(SRCARCH)/lib/lib1funcs.S FORCE
+$(obj)/lib1funcs.S: $(srctree)/arch/$(SRCARCH)/lib/lib1funcs.S

Quoted 2 lines

? ? ? ?$(call cmd,shipped)

You should be able to avoid the extra copy altogether by doing something ala:

$(obj)/lib1funcs.o: $(srctree)/arch/arm/lib/lib1funcs.S ? ? ? ?$(call cmd,as_o_S)

Quoted 6 lines

Quoted 3 lines

note that I also remove the $(SRCARCH), as there is no other arch/*/lib/lib1funcs.S' than arch/arm/lib/lib1funcs.S'

I withdraw this proposal and will hack around this to find a proper solution from within kbuild, and eventually come back on these uses :-)

Any progress on this?

Quoted 2 lines

I have a patch doing multiple similar $(call cmd,shipped) at the moment and this is far from looking nice.

What is your use-case ? Is it re-use of code in a different subdirectory (use-case presented in this thread), or aliasing of the same source under different object name in the same directory (as used in the alpha tree) ?

Quoted 40 lines · Arnaud Lacombe

Hi,

Quoted 37 lines · Nicolas Pitre

Quoted 36 lines · Arnaud Lacombe

Quoted 26 lines · Arnaud Lacombe

Quoted 14 lines · Stephen Boyd

arch/arm/boot/compressed/Makefile +1 -1

index 0c74a6f..937fd26 100644
@@ -91,7 +91,7 @@ suffix_$(CONFIG_KERNEL_LZMA) = lzma
 
  targets       := vmlinux vmlinux.lds \
                 piggy.$(suffix_y) piggy.$(suffix_y).o \
-                font.o font.c head.o misc.o $(OBJS)
+                font.o font.c head.o misc.o lib1funcs.o lib1funcs.S $(OBJS)
 
  # Make sure files are removed during clean
  extra-y       += piggy.gzip piggy.lzo piggy.lzma lib1funcs.S

arch/arm/boot/compressed/Makefile LDFLAGS_vmlinux += -X · line 126

Quoted 9 lines

arch/arm/boot/compressed/Makefile +1 -3

@@ -121,9 +121,7 @@ LDFLAGS_vmlinux += -X
  LDFLAGS_vmlinux += -T
 
  # For __aeabi_uidivmod
-lib1funcs = $(obj)/lib1funcs.o
-
-$(obj)/lib1funcs.S: $(srctree)/arch/$(SRCARCH)/lib/lib1funcs.S FORCE
+$(obj)/lib1funcs.S: $(srctree)/arch/$(SRCARCH)/lib/lib1funcs.S
        $(call cmd,shipped)
 

You should be able to avoid the extra copy altogether by doing something ala:

Quoted 6 lines

$(obj)/lib1funcs.o: $(srctree)/arch/arm/lib/lib1funcs.S

        $(call cmd,as_o_S)

note that I also remove the $(SRCARCH), as there is no other arch/*/lib/lib1funcs.S' than arch/arm/lib/lib1funcs.S'

I withdraw this proposal and will hack around this to find a proper solution from within kbuild, and eventually come back on these uses :-)

Quoted 8 lines

Quoted 4 lines

Any progress on this?

I have a patch doing multiple similar $(call cmd,shipped) at the moment and this is far from looking nice.

What is your use-case ? Is it re-use of code in a different subdirectory (use-case presented in this thread), or aliasing of the same source under different object name in the same directory (as used in the alpha tree) ?

It is to be able to reuse the same file source file in both the main kernel and the decompressor, sometimes rebuilding it with differing options from the main kernel build.

As the two environments are entirely separate, it is not always appropriate to clone the previously built object file.

Hence, we copy the source file and re-build it.

The alternative is that we could keep two copies of the same source in two different locations, but that's just plain idiotic just to satisfy some silly kbuild restriction.

Quoted 70 lines · Russell King - ARM Linux

Quoted 53 lines · Arnaud Lacombe

Hi,

Quoted 49 lines · On Wed, Aug 17, 2011 at 11:44 PM, Nicolas Pitre<[email protected]> ?wrote:

Quoted 38 lines · Arnaud Lacombe

Quoted 35 lines · On Fri, Aug 12, 2011 at 4:48 PM, Arnaud Lacombe<[email protected]> ?wrote:

Quoted 24 lines · On Fri, Aug 12, 2011 at 3:00 PM, Stephen Boyd<[email protected]> ?wrote:

arch/arm/boot/compressed/Makefile +1 -1

index 0c74a6f..937fd26 100644
@@ -91,7 +91,7 @@ suffix_$(CONFIG_KERNEL_LZMA) = lzma
 
 ?targets ? ? ? := vmlinux vmlinux.lds \
 ? ? ? ? ? ? ? ? piggy.$(suffix_y) piggy.$(suffix_y).o \
- ? ? ? ? ? ? ? ?font.o font.c head.o misc.o $(OBJS)
+ ? ? ? ? ? ? ? ?font.o font.c head.o misc.o lib1funcs.o lib1funcs.S
 $(OBJS)
 

?# Make sure files are removed during clean ?extra-y ? ? ? += piggy.gzip piggy.lzo piggy.lzma lib1funcs.S

arch/arm/boot/compressed/Makefile +0 -0

@@ -121,9 +121,7 @@ LDFLAGS_vmlinux += -X

?LDFLAGS_vmlinux += -T

?# For __aeabi_uidivmod

arch/arm/boot/compressed/Makefile +1 -3

-lib1funcs = $(obj)/lib1funcs.o
-
-$(obj)/lib1funcs.S: $(srctree)/arch/$(SRCARCH)/lib/lib1funcs.S FORCE
+$(obj)/lib1funcs.S: $(srctree)/arch/$(SRCARCH)/lib/lib1funcs.S

Quoted 2 lines

? ? ? ?$(call cmd,shipped)

You should be able to avoid the extra copy altogether by doing something ala:

$(obj)/lib1funcs.o: $(srctree)/arch/arm/lib/lib1funcs.S ? ? ? ?$(call cmd,as_o_S)

Quoted 6 lines

Quoted 3 lines

note that I also remove the $(SRCARCH), as there is no other arch/*/lib/lib1funcs.S' than arch/arm/lib/lib1funcs.S'

I withdraw this proposal and will hack around this to find a proper solution from within kbuild, and eventually come back on these uses :-)

Any progress on this?

Quoted 7 lines

Quoted 2 lines

I have a patch doing multiple similar $(call cmd,shipped) at the moment and this is far from looking nice.

What is your use-case ? Is it re-use of code in a different subdirectory (use-case presented in this thread), or aliasing of the same source under different object name in the same directory (as used in the alpha tree) ?

It is to be able to reuse the same file source file in both the main kernel and the decompressor, sometimes rebuilding it with differing options from the main kernel build.

As the two environments are entirely separate, it is not always appropriate to clone the previously built object file.

Quoted 6 lines

Hence, we copy the source file and re-build it.

The alternative is that we could keep two copies of the same source in two different locations, but that's just plain idiotic just to satisfy some silly kbuild restriction.

Can the second file just contain a "#include " of the 1st?

Quoted 15 lines · Stephen Boyd

I was hoping with the recent patch e78e8f2 (kernel: prevent unnecessary rebuilding due to config_data.gz, 2011-07-05) compiling ARM linux a second time would amount to no more linking. This doesn't seem to be the case though. Doing a make V=2 I see that lib1funcs.S is shipped and thus we have to recompile it although nothing actually changed. This in turn requires us to relink the compressed vmlinux and then recreate the zImage.

? Kernel: arch/arm/boot/Image is ready
? SHIPPED arch/arm/boot/compressed/lib1funcs.S - due to missing .cmd file
? AS ? ? ?arch/arm/boot/compressed/lib1funcs.o - due to: arch/arm/boot/compressed/lib1funcs.S ? LD ? ? ?arch/arm/boot/compressed/vmlinux - due to: arch/arm/boot/compressed/lib1funcs.o ? OBJCOPY arch/arm/boot/zImage - due to: arch/arm/boot/compressed/vmlinux
? Kernel: arch/arm/boot/zImage is ready

Quoted 2 lines

Is there any way to avoid this? Perhaps the shipped command could become a bit wiser?

Following patch will likely fix it:

arch/arm/boot/compressed/Makefile +0 -0

index 0c74a6f..80b6b6e 100644
@@ -123,7 +123,7 @@ LDFLAGS_vmlinux += -T

?# For __aeabi_uidivmod
?lib1funcs = $(obj)/lib1funcs.o

-$(obj)/lib1funcs.S: $(srctree)/arch/$(SRCARCH)/lib/lib1funcs.S FORCE +$(obj)/lib1funcs.S: $(srctree)/arch/$(SRCARCH)/lib/lib1funcs.S ? ? ? ?$(call cmd,shipped)

?# We need to prevent any GOTOFF relocs being used with references

(cut'n'pasted ...)

The FORCE prerequisite will tell make to always execute the command. But we only want to execute the command if:
1) $(obj)/lib1funcs.S is missing
2) or $(srctree)/arch/$(SRCARCH)/lib/lib1funcs.S is not older then $(obj)/lib1funcs.S

So dropping FORCE should be a safe thing to do.

? ? ? ?Sam
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Hi,

Quoted 28 lines · Sam Ravnborg

Quoted 15 lines · Stephen Boyd

I was hoping with the recent patch e78e8f2 (kernel: prevent unnecessary rebuilding due to config_data.gz, 2011-07-05) compiling ARM linux a second time would amount to no more linking. This doesn't seem to be the case though. Doing a make V=2 I see that lib1funcs.S is shipped and thus we have to recompile it although nothing actually changed. This in turn requires us to relink the compressed vmlinux and then recreate the zImage.

? Kernel: arch/arm/boot/Image is ready
? SHIPPED arch/arm/boot/compressed/lib1funcs.S - due to missing .cmd file
? AS ? ? ?arch/arm/boot/compressed/lib1funcs.o - due to: arch/arm/boot/compressed/lib1funcs.S ? LD ? ? ?arch/arm/boot/compressed/vmlinux - due to: arch/arm/boot/compressed/lib1funcs.o ? OBJCOPY arch/arm/boot/zImage - due to: arch/arm/boot/compressed/vmlinux
? Kernel: arch/arm/boot/zImage is ready

Quoted 2 lines

Is there any way to avoid this? Perhaps the shipped command could become a bit wiser?

Following patch will likely fix it:

arch/arm/boot/compressed/Makefile +0 -0

index 0c74a6f..80b6b6e 100644
@@ -123,7 +123,7 @@ LDFLAGS_vmlinux += -T

?# For __aeabi_uidivmod
?lib1funcs = $(obj)/lib1funcs.o

Quoted 4 lines

-$(obj)/lib1funcs.S: $(srctree)/arch/$(SRCARCH)/lib/lib1funcs.S FORCE +$(obj)/lib1funcs.S: $(srctree)/arch/$(SRCARCH)/lib/lib1funcs.S ? ? ? ?$(call cmd,shipped)

AFAIK, we have a generic rule to handle shipped files:

from scripts/Makefile.lib:

$(obj)/%: $(src)/%_shipped

        $(call cmd,shipped)

so, that rule should not be needed at all.

Quoted 39 lines · Arnaud Lacombe

Hi,

Quoted 28 lines · Sam Ravnborg

Quoted 15 lines · Stephen Boyd

I was hoping with the recent patch e78e8f2 (kernel: prevent unnecessary rebuilding due to config_data.gz, 2011-07-05) compiling ARM linux a second time would amount to no more linking. This doesn't seem to be the case though. Doing a make V=2 I see that lib1funcs.S is shipped and thus we have to recompile it although nothing actually changed. This in turn requires us to relink the compressed vmlinux and then recreate the zImage.

? Kernel: arch/arm/boot/Image is ready
? SHIPPED arch/arm/boot/compressed/lib1funcs.S - due to missing .cmd file
? AS ? ? ?arch/arm/boot/compressed/lib1funcs.o - due to: arch/arm/boot/compressed/lib1funcs.S ? LD ? ? ?arch/arm/boot/compressed/vmlinux - due to: arch/arm/boot/compressed/lib1funcs.o ? OBJCOPY arch/arm/boot/zImage - due to: arch/arm/boot/compressed/vmlinux
? Kernel: arch/arm/boot/zImage is ready

Quoted 2 lines

Is there any way to avoid this? Perhaps the shipped command could become a bit wiser?

Following patch will likely fix it:

arch/arm/boot/compressed/Makefile +0 -0

index 0c74a6f..80b6b6e 100644
@@ -123,7 +123,7 @@ LDFLAGS_vmlinux += -T

?# For __aeabi_uidivmod
?lib1funcs = $(obj)/lib1funcs.o

Quoted 4 lines

-$(obj)/lib1funcs.S: $(srctree)/arch/$(SRCARCH)/lib/lib1funcs.S FORCE +$(obj)/lib1funcs.S: $(srctree)/arch/$(SRCARCH)/lib/lib1funcs.S ? ? ? ?$(call cmd,shipped)

AFAIK, we have a generic rule to handle shipped files:

from scripts/Makefile.lib:

Quoted 4 lines

$(obj)/%: $(src)/%_shipped
? ? ? ? $(call cmd,shipped)

so, that rule should not be needed at all.

In this case the cmd_shipped is misused to make a copy of a file. So the generic rule does not apply.