X-Git-Url: http://pileus.org/git/?a=blobdiff_plain;f=Documentation%2Fkbuild%2Fmakefiles.txt;h=51104f9194a54feb64058f4b8f35f3b4d7cbc88f;hb=52435bfc665716fdf9a02f0d08e7ce50ddb9bf45;hp=f099b814d383c49d44667954fe9e625c90c9a6e4;hpb=fb9fc395174138983a49f2da982ed14caabbe741;p=~andy%2Flinux

diff --git a/Documentation/kbuild/makefiles.txt b/Documentation/kbuild/makefiles.txt
index f099b814d38..51104f9194a 100644
--- a/Documentation/kbuild/makefiles.txt
+++ b/Documentation/kbuild/makefiles.txt
@@ -383,6 +383,20 @@ more details, with real examples.
 	to prerequisites are referenced with $(src) (because they are not
 	generated files).
 
+    $(kecho)
+	echoing information to user in a rule is often a good practice
+	but when execution "make -s" one does not expect to see any output
+	except for warnings/errors.
+	To support this kbuild define $(kecho) which will echo out the
+	text following $(kecho) to stdout except if "make -s" is used.
+
+	Example:
+		#arch/blackfin/boot/Makefile
+		$(obj)/vmImage: $(obj)/vmlinux.gz
+			$(call if_changed,uimage)
+			@$(kecho) 'Kernel: $@ is ready'
+
+
 --- 3.11 $(CC) support functions
 
 	The kernel may be built with several different versions of
@@ -518,6 +532,28 @@ more details, with real examples.
 	In this example for a specific GCC version the build will error out explaining
 	to the user why it stops.
 
+    cc-cross-prefix
+	cc-cross-prefix is used to check if there exists a $(CC) in path with
+	one of the listed prefixes. The first prefix where there exist a
+	prefix$(CC) in the PATH is returned - and if no prefix$(CC) is found
+	then nothing is returned.
+	Additional prefixes are separated by a single space in the
+	call of cc-cross-prefix.
+	This functionality is useful for architecture Makefiles that try
+	to set CROSS_COMPILE to well-known values but may have several
+	values to select between.
+	It is recommended only to try to set CROSS_COMPILE if it is a cross
+	build (host arch is different from target arch). And if CROSS_COMPILE
+	is already set then leave it with the old value.
+
+	Example:
+		#arch/m68k/Makefile
+		ifneq ($(SUBARCH),$(ARCH))
+		        ifeq ($(CROSS_COMPILE),)
+		               CROSS_COMPILE := $(call cc-cross-prefix, m68k-linux-gnu-)
+			endif
+		endif
+
 === 4 Host Program support
 
 Kbuild supports building executables on the host for use during the