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-rw-r--r--Documentation/kbuild/makefiles.txt36
1 files changed, 36 insertions, 0 deletions
diff --git a/Documentation/kbuild/makefiles.txt b/Documentation/kbuild/makefiles.txt
index 40e082bb8c5..835b64acf0b 100644
--- a/Documentation/kbuild/makefiles.txt
+++ b/Documentation/kbuild/makefiles.txt
@@ -40,11 +40,13 @@ This document describes the Linux kernel Makefiles.
40 --- 6.6 Commands useful for building a boot image 40 --- 6.6 Commands useful for building a boot image
41 --- 6.7 Custom kbuild commands 41 --- 6.7 Custom kbuild commands
42 --- 6.8 Preprocessing linker scripts 42 --- 6.8 Preprocessing linker scripts
43 --- 6.9 Generic header files
43 44
44 === 7 Kbuild syntax for exported headers 45 === 7 Kbuild syntax for exported headers
45 --- 7.1 header-y 46 --- 7.1 header-y
46 --- 7.2 objhdr-y 47 --- 7.2 objhdr-y
47 --- 7.3 destination-y 48 --- 7.3 destination-y
49 --- 7.4 generic-y
48 50
49 === 8 Kbuild Variables 51 === 8 Kbuild Variables
50 === 9 Makefile language 52 === 9 Makefile language
@@ -1214,6 +1216,14 @@ When kbuild executes, the following steps are followed (roughly):
1214 The kbuild infrastructure for *lds file are used in several 1216 The kbuild infrastructure for *lds file are used in several
1215 architecture-specific files. 1217 architecture-specific files.
1216 1218
1219--- 6.9 Generic header files
1220
1221 The directory include/asm-generic contains the header files
1222 that may be shared between individual architectures.
1223 The recommended approach how to use a generic header file is
1224 to list the file in the Kbuild file.
1225 See "7.4 generic-y" for further info on syntax etc.
1226
1217=== 7 Kbuild syntax for exported headers 1227=== 7 Kbuild syntax for exported headers
1218 1228
1219The kernel include a set of headers that is exported to userspace. 1229The kernel include a set of headers that is exported to userspace.
@@ -1270,6 +1280,32 @@ See subsequent chapter for the syntax of the Kbuild file.
1270 In the example above all exported headers in the Kbuild file 1280 In the example above all exported headers in the Kbuild file
1271 will be located in the directory "include/linux" when exported. 1281 will be located in the directory "include/linux" when exported.
1272 1282
1283 --- 7.4 generic-y
1284
1285 If an architecture uses a verbatim copy of a header from
1286 include/asm-generic then this is listed in the file
1287 arch/$(ARCH)/include/asm/Kbuild like this:
1288
1289 Example:
1290 #arch/x86/include/asm/Kbuild
1291 generic-y += termios.h
1292 generic-y += rtc.h
1293
1294 During the prepare phase of the build a wrapper include
1295 file is generated in the directory:
1296
1297 arch/$(ARCH)/include/generated/asm
1298
1299 When a header is exported where the architecture uses
1300 the generic header a similar wrapper is generated as part
1301 of the set of exported headers in the directory:
1302
1303 usr/include/asm
1304
1305 The generated wrapper will in both cases look like the following:
1306
1307 Example: termios.h
1308 #include <asm-generic/termios.h>
1273 1309
1274=== 8 Kbuild Variables 1310=== 8 Kbuild Variables
1275 1311