Add "Map" kbuild option, so that "make Map=1" would save vmlinux linker
map into vmlinux.map, which is quite useful during making kernel changes
related to how the kernel is composed.
KBUILD_SAVE_LINK_MAP flag is exported and architectures
supporting compressed kernel images might respect it and produce
arch/*/boot/compressed/vmlinux.map for the decompressor code as well.
Signed-off-by: Vasily Gorbik <gor@xxxxxxxxxxxxx>
---
.gitignore | 1 +
Makefile | 14 ++++++++++++++
2 files changed, 15 insertions(+)
diff --git a/.gitignore b/.gitignore
index 97ba6b79834c..1d2308e597ad 100644
--- a/.gitignore
+++ b/.gitignore
@@ -44,6 +44,7 @@
*.xz
Module.symvers
modules.builtin
+vmlinux.map
#
# Top-level generic files
diff --git a/Makefile b/Makefile
index 7a3c4548162b..f1790deae03b 100644
--- a/Makefile
+++ b/Makefile
@@ -176,6 +176,14 @@ ifndef KBUILD_CHECKSRC
KBUILD_CHECKSRC = 0
endif
+# Use 'make Map=1' to enable saving linker map file(s):
+# vmlinux.map for vmlinux,
+# (arch/*/boot/compressed/vmlinux.map for arch/*/boot/compressed/vmlinux)
+
+ifeq ("$(origin Map)", "command line")
+ export KBUILD_SAVE_LINK_MAP := $(Map)
+endif
+
# Use make M=dir to specify directory of external module to build
# Old syntax make ... SUBDIRS=$PWD is still supported
# Setting the environment variable KBUILD_EXTMOD take precedence
@@ -838,6 +846,11 @@ ifeq ($(CONFIG_STRIP_ASM_SYMS),y)
LDFLAGS_vmlinux += $(call ld-option, -X,)
endif
+ifdef KBUILD_SAVE_LINK_MAP
+LDFLAGS_vmlinux += -Map=vmlinux.map
+CLEAN_FILES += vmlinux.map
+endif
+
# insure the checker run with the right endianness
CHECKFLAGS += $(if $(CONFIG_CPU_BIG_ENDIAN),-mbig-endian,-mlittle-endian)
@@ -1434,6 +1447,7 @@ help:
@echo ' 2: warnings which occur quite often but may still be relevant'
@echo ' 3: more obscure warnings, can most likely be ignored'
@echo ' Multiple levels can be combined with W=12 or W=123'
+ @echo ' make Map=1 [targets] Save vmlinux linker map file(s)'
@echo ''
@echo 'Execute "make" or "make all" to build all targets marked with [*] '
@echo 'For further info see the ./README file'
--
2.18.0.13.gd42ae10
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