Thread (22 messages) 22 messages, 6 authors, 2011-08-18

[PATCH] ARM: zImage: Skip relinking if nothing changes

From: Arnaud Lacombe <hidden>
Date: 2011-08-12 20:48:16
Also in: linux-kbuild, lkml

Hi,

On Fri, Aug 12, 2011 at 3:00 PM, Stephen Boyd [off-list ref] wrote:
quoted hunk ↗ jump to hunk
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 <redacted>
Acked-by: Sam Ravnborg <redacted>
---
?arch/arm/boot/compressed/Makefile | ? ?8 +++-----
?1 files changed, 3 insertions(+), 5 deletions(-)
diff --git a/arch/arm/boot/compressed/Makefile b/arch/arm/boot/compressed/Makefile
index 0c74a6f..937fd26 100644
--- a/arch/arm/boot/compressed/Makefile
+++ b/arch/arm/boot/compressed/Makefile
@@ -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
@@ -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:

$(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'

 - Arnaud
quoted hunk ↗ jump to hunk
?# We need to prevent any GOTOFF relocs being used with references
@@ -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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