Merge branches 'fixes', 'cleanups' and 'boards'

[~andy/linux] / Documentation / kbuild / makefiles.txt

diff --git a/Documentation/kbuild/makefiles.txt b/Documentation/kbuild/makefiles.txt
index f099b814d383c49d44667954fe9e625c90c9a6e4..51104f9194a54feb64058f4b8f35f3b4d7cbc88f 100644 (file)
--- 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