diff options
-rw-r--r-- | Documentation/kbuild/makefiles.txt | 166 | ||||
-rw-r--r-- | Makefile | 32 | ||||
-rw-r--r-- | scripts/Kbuild.include | 37 | ||||
-rw-r--r-- | scripts/Makefile.build | 3 |
4 files changed, 136 insertions, 102 deletions
diff --git a/Documentation/kbuild/makefiles.txt b/Documentation/kbuild/makefiles.txt index 443230b43e09..99d51a5bb0d9 100644 --- a/Documentation/kbuild/makefiles.txt +++ b/Documentation/kbuild/makefiles.txt | |||
@@ -17,6 +17,7 @@ This document describes the Linux kernel Makefiles. | |||
17 | --- 3.8 Command line dependency | 17 | --- 3.8 Command line dependency |
18 | --- 3.9 Dependency tracking | 18 | --- 3.9 Dependency tracking |
19 | --- 3.10 Special Rules | 19 | --- 3.10 Special Rules |
20 | --- 3.11 $(CC) support functions | ||
20 | 21 | ||
21 | === 4 Host Program support | 22 | === 4 Host Program support |
22 | --- 4.1 Simple Host Program | 23 | --- 4.1 Simple Host Program |
@@ -38,7 +39,6 @@ This document describes the Linux kernel Makefiles. | |||
38 | --- 6.6 Commands useful for building a boot image | 39 | --- 6.6 Commands useful for building a boot image |
39 | --- 6.7 Custom kbuild commands | 40 | --- 6.7 Custom kbuild commands |
40 | --- 6.8 Preprocessing linker scripts | 41 | --- 6.8 Preprocessing linker scripts |
41 | --- 6.9 $(CC) support functions | ||
42 | 42 | ||
43 | === 7 Kbuild Variables | 43 | === 7 Kbuild Variables |
44 | === 8 Makefile language | 44 | === 8 Makefile language |
@@ -385,6 +385,102 @@ more details, with real examples. | |||
385 | to prerequisites are referenced with $(src) (because they are not | 385 | to prerequisites are referenced with $(src) (because they are not |
386 | generated files). | 386 | generated files). |
387 | 387 | ||
388 | --- 3.11 $(CC) support functions | ||
389 | |||
390 | The kernel may be build with several different versions of | ||
391 | $(CC), each supporting a unique set of features and options. | ||
392 | kbuild provide basic support to check for valid options for $(CC). | ||
393 | $(CC) is useally the gcc compiler, but other alternatives are | ||
394 | available. | ||
395 | |||
396 | as-option | ||
397 | as-option is used to check if $(CC) when used to compile | ||
398 | assembler (*.S) files supports the given option. An optional | ||
399 | second option may be specified if first option are not supported. | ||
400 | |||
401 | Example: | ||
402 | #arch/sh/Makefile | ||
403 | cflags-y += $(call as-option,-Wa$(comma)-isa=$(isa-y),) | ||
404 | |||
405 | In the above example cflags-y will be assinged the the option | ||
406 | -Wa$(comma)-isa=$(isa-y) if it is supported by $(CC). | ||
407 | The second argument is optional, and if supplied will be used | ||
408 | if first argument is not supported. | ||
409 | |||
410 | cc-option | ||
411 | cc-option is used to check if $(CC) support a given option, and not | ||
412 | supported to use an optional second option. | ||
413 | |||
414 | Example: | ||
415 | #arch/i386/Makefile | ||
416 | cflags-y += $(call cc-option,-march=pentium-mmx,-march=i586) | ||
417 | |||
418 | In the above example cflags-y will be assigned the option | ||
419 | -march=pentium-mmx if supported by $(CC), otherwise -march-i586. | ||
420 | The second argument to cc-option is optional, and if omitted | ||
421 | cflags-y will be assigned no value if first option is not supported. | ||
422 | |||
423 | cc-option-yn | ||
424 | cc-option-yn is used to check if gcc supports a given option | ||
425 | and return 'y' if supported, otherwise 'n'. | ||
426 | |||
427 | Example: | ||
428 | #arch/ppc/Makefile | ||
429 | biarch := $(call cc-option-yn, -m32) | ||
430 | aflags-$(biarch) += -a32 | ||
431 | cflags-$(biarch) += -m32 | ||
432 | |||
433 | In the above example $(biarch) is set to y if $(CC) supports the -m32 | ||
434 | option. When $(biarch) equals to y the expanded variables $(aflags-y) | ||
435 | and $(cflags-y) will be assigned the values -a32 and -m32. | ||
436 | |||
437 | cc-option-align | ||
438 | gcc version >= 3.0 shifted type of options used to speify | ||
439 | alignment of functions, loops etc. $(cc-option-align) whrn used | ||
440 | as prefix to the align options will select the right prefix: | ||
441 | gcc < 3.00 | ||
442 | cc-option-align = -malign | ||
443 | gcc >= 3.00 | ||
444 | cc-option-align = -falign | ||
445 | |||
446 | Example: | ||
447 | CFLAGS += $(cc-option-align)-functions=4 | ||
448 | |||
449 | In the above example the option -falign-functions=4 is used for | ||
450 | gcc >= 3.00. For gcc < 3.00 -malign-functions=4 is used. | ||
451 | |||
452 | cc-version | ||
453 | cc-version return a numerical version of the $(CC) compiler version. | ||
454 | The format is <major><minor> where both are two digits. So for example | ||
455 | gcc 3.41 would return 0341. | ||
456 | cc-version is useful when a specific $(CC) version is faulty in one | ||
457 | area, for example the -mregparm=3 were broken in some gcc version | ||
458 | even though the option was accepted by gcc. | ||
459 | |||
460 | Example: | ||
461 | #arch/i386/Makefile | ||
462 | cflags-y += $(shell \ | ||
463 | if [ $(call cc-version) -ge 0300 ] ; then \ | ||
464 | echo "-mregparm=3"; fi ;) | ||
465 | |||
466 | In the above example -mregparm=3 is only used for gcc version greater | ||
467 | than or equal to gcc 3.0. | ||
468 | |||
469 | cc-ifversion | ||
470 | cc-ifversion test the version of $(CC) and equals last argument if | ||
471 | version expression is true. | ||
472 | |||
473 | Example: | ||
474 | #fs/reiserfs/Makefile | ||
475 | EXTRA_CFLAGS := $(call cc-ifversion, -lt, 0402, -O1) | ||
476 | |||
477 | In this example EXTRA_CFLAGS will be assigned the value -O1 if the | ||
478 | $(CC) version is less than 4.2. | ||
479 | cc-ifversion takes all the shell operators: | ||
480 | -eq, -ne, -lt, -le, -gt, and -ge | ||
481 | The third parameter may be a text as in this example, but it may also | ||
482 | be an expanded variable or a macro. | ||
483 | |||
388 | 484 | ||
389 | === 4 Host Program support | 485 | === 4 Host Program support |
390 | 486 | ||
@@ -973,74 +1069,6 @@ When kbuild executes the following steps are followed (roughly): | |||
973 | architecture specific files. | 1069 | architecture specific files. |
974 | 1070 | ||
975 | 1071 | ||
976 | --- 6.9 $(CC) support functions | ||
977 | |||
978 | The kernel may be build with several different versions of | ||
979 | $(CC), each supporting a unique set of features and options. | ||
980 | kbuild provide basic support to check for valid options for $(CC). | ||
981 | $(CC) is useally the gcc compiler, but other alternatives are | ||
982 | available. | ||
983 | |||
984 | cc-option | ||
985 | cc-option is used to check if $(CC) support a given option, and not | ||
986 | supported to use an optional second option. | ||
987 | |||
988 | Example: | ||
989 | #arch/i386/Makefile | ||
990 | cflags-y += $(call cc-option,-march=pentium-mmx,-march=i586) | ||
991 | |||
992 | In the above example cflags-y will be assigned the option | ||
993 | -march=pentium-mmx if supported by $(CC), otherwise -march-i586. | ||
994 | The second argument to cc-option is optional, and if omitted | ||
995 | cflags-y will be assigned no value if first option is not supported. | ||
996 | |||
997 | cc-option-yn | ||
998 | cc-option-yn is used to check if gcc supports a given option | ||
999 | and return 'y' if supported, otherwise 'n'. | ||
1000 | |||
1001 | Example: | ||
1002 | #arch/ppc/Makefile | ||
1003 | biarch := $(call cc-option-yn, -m32) | ||
1004 | aflags-$(biarch) += -a32 | ||
1005 | cflags-$(biarch) += -m32 | ||
1006 | |||
1007 | In the above example $(biarch) is set to y if $(CC) supports the -m32 | ||
1008 | option. When $(biarch) equals to y the expanded variables $(aflags-y) | ||
1009 | and $(cflags-y) will be assigned the values -a32 and -m32. | ||
1010 | |||
1011 | cc-option-align | ||
1012 | gcc version >= 3.0 shifted type of options used to speify | ||
1013 | alignment of functions, loops etc. $(cc-option-align) whrn used | ||
1014 | as prefix to the align options will select the right prefix: | ||
1015 | gcc < 3.00 | ||
1016 | cc-option-align = -malign | ||
1017 | gcc >= 3.00 | ||
1018 | cc-option-align = -falign | ||
1019 | |||
1020 | Example: | ||
1021 | CFLAGS += $(cc-option-align)-functions=4 | ||
1022 | |||
1023 | In the above example the option -falign-functions=4 is used for | ||
1024 | gcc >= 3.00. For gcc < 3.00 -malign-functions=4 is used. | ||
1025 | |||
1026 | cc-version | ||
1027 | cc-version return a numerical version of the $(CC) compiler version. | ||
1028 | The format is <major><minor> where both are two digits. So for example | ||
1029 | gcc 3.41 would return 0341. | ||
1030 | cc-version is useful when a specific $(CC) version is faulty in one | ||
1031 | area, for example the -mregparm=3 were broken in some gcc version | ||
1032 | even though the option was accepted by gcc. | ||
1033 | |||
1034 | Example: | ||
1035 | #arch/i386/Makefile | ||
1036 | cflags-y += $(shell \ | ||
1037 | if [ $(call cc-version) -ge 0300 ] ; then \ | ||
1038 | echo "-mregparm=3"; fi ;) | ||
1039 | |||
1040 | In the above example -mregparm=3 is only used for gcc version greater | ||
1041 | than or equal to gcc 3.0. | ||
1042 | |||
1043 | |||
1044 | === 7 Kbuild Variables | 1072 | === 7 Kbuild Variables |
1045 | 1073 | ||
1046 | The top Makefile exports the following variables: | 1074 | The top Makefile exports the following variables: |
@@ -258,38 +258,6 @@ endif | |||
258 | 258 | ||
259 | export quiet Q KBUILD_VERBOSE | 259 | export quiet Q KBUILD_VERBOSE |
260 | 260 | ||
261 | ###### | ||
262 | # cc support functions to be used (only) in arch/$(ARCH)/Makefile | ||
263 | # See documentation in Documentation/kbuild/makefiles.txt | ||
264 | |||
265 | # as-option | ||
266 | # Usage: cflags-y += $(call as-option, -Wa$(comma)-isa=foo,) | ||
267 | |||
268 | as-option = $(shell if $(CC) $(CFLAGS) $(1) -Wa,-Z -c -o /dev/null \ | ||
269 | -xassembler /dev/null > /dev/null 2>&1; then echo "$(1)"; \ | ||
270 | else echo "$(2)"; fi ;) | ||
271 | |||
272 | # cc-option | ||
273 | # Usage: cflags-y += $(call cc-option, -march=winchip-c6, -march=i586) | ||
274 | |||
275 | cc-option = $(shell if $(CC) $(CFLAGS) $(1) -S -o /dev/null -xc /dev/null \ | ||
276 | > /dev/null 2>&1; then echo "$(1)"; else echo "$(2)"; fi ;) | ||
277 | |||
278 | # cc-option-yn | ||
279 | # Usage: flag := $(call cc-option-yn, -march=winchip-c6) | ||
280 | cc-option-yn = $(shell if $(CC) $(CFLAGS) $(1) -S -o /dev/null -xc /dev/null \ | ||
281 | > /dev/null 2>&1; then echo "y"; else echo "n"; fi;) | ||
282 | |||
283 | # cc-option-align | ||
284 | # Prefix align with either -falign or -malign | ||
285 | cc-option-align = $(subst -functions=0,,\ | ||
286 | $(call cc-option,-falign-functions=0,-malign-functions=0)) | ||
287 | |||
288 | # cc-version | ||
289 | # Usage gcc-ver := $(call cc-version $(CC)) | ||
290 | cc-version = $(shell $(CONFIG_SHELL) $(srctree)/scripts/gcc-version.sh \ | ||
291 | $(if $(1), $(1), $(CC))) | ||
292 | |||
293 | 261 | ||
294 | # Look for make include files relative to root of kernel src | 262 | # Look for make include files relative to root of kernel src |
295 | MAKEFLAGS += --include-dir=$(srctree) | 263 | MAKEFLAGS += --include-dir=$(srctree) |
diff --git a/scripts/Kbuild.include b/scripts/Kbuild.include index 0168d6c37075..92ce94b58bd6 100644 --- a/scripts/Kbuild.include +++ b/scripts/Kbuild.include | |||
@@ -44,6 +44,43 @@ define filechk | |||
44 | fi | 44 | fi |
45 | endef | 45 | endef |
46 | 46 | ||
47 | ###### | ||
48 | # cc support functions to be used (only) in arch/$(ARCH)/Makefile | ||
49 | # See documentation in Documentation/kbuild/makefiles.txt | ||
50 | |||
51 | # as-option | ||
52 | # Usage: cflags-y += $(call as-option, -Wa$(comma)-isa=foo,) | ||
53 | |||
54 | as-option = $(shell if $(CC) $(CFLAGS) $(1) -Wa,-Z -c -o /dev/null \ | ||
55 | -xassembler /dev/null > /dev/null 2>&1; then echo "$(1)"; \ | ||
56 | else echo "$(2)"; fi ;) | ||
57 | |||
58 | # cc-option | ||
59 | # Usage: cflags-y += $(call cc-option, -march=winchip-c6, -march=i586) | ||
60 | |||
61 | cc-option = $(shell if $(CC) $(CFLAGS) $(1) -S -o /dev/null -xc /dev/null \ | ||
62 | > /dev/null 2>&1; then echo "$(1)"; else echo "$(2)"; fi ;) | ||
63 | |||
64 | # cc-option-yn | ||
65 | # Usage: flag := $(call cc-option-yn, -march=winchip-c6) | ||
66 | cc-option-yn = $(shell if $(CC) $(CFLAGS) $(1) -S -o /dev/null -xc /dev/null \ | ||
67 | > /dev/null 2>&1; then echo "y"; else echo "n"; fi;) | ||
68 | |||
69 | # cc-option-align | ||
70 | # Prefix align with either -falign or -malign | ||
71 | cc-option-align = $(subst -functions=0,,\ | ||
72 | $(call cc-option,-falign-functions=0,-malign-functions=0)) | ||
73 | |||
74 | # cc-version | ||
75 | # Usage gcc-ver := $(call cc-version, $(CC)) | ||
76 | cc-version = $(shell $(CONFIG_SHELL) $(srctree)/scripts/gcc-version.sh \ | ||
77 | $(if $(1), $(1), $(CC))) | ||
78 | |||
79 | # cc-ifversion | ||
80 | # Usage: EXTRA_CFLAGS += $(call cc-ifversion, -lt, 0402, -O1) | ||
81 | cc-ifversion = $(shell if [ $(call cc-version, $(CC)) $(1) $(2) ]; then \ | ||
82 | echo $(3); fi;) | ||
83 | |||
47 | ### | 84 | ### |
48 | # Shorthand for $(Q)$(MAKE) -f scripts/Makefile.build obj= | 85 | # Shorthand for $(Q)$(MAKE) -f scripts/Makefile.build obj= |
49 | # Usage: | 86 | # Usage: |
diff --git a/scripts/Makefile.build b/scripts/Makefile.build index c33e62bde6b0..2737765f2fb4 100644 --- a/scripts/Makefile.build +++ b/scripts/Makefile.build | |||
@@ -10,11 +10,12 @@ __build: | |||
10 | # Read .config if it exist, otherwise ignore | 10 | # Read .config if it exist, otherwise ignore |
11 | -include .config | 11 | -include .config |
12 | 12 | ||
13 | include scripts/Kbuild.include | ||
14 | |||
13 | # The filename Kbuild has precedence over Makefile | 15 | # The filename Kbuild has precedence over Makefile |
14 | kbuild-dir := $(if $(filter /%,$(src)),$(src),$(srctree)/$(src)) | 16 | kbuild-dir := $(if $(filter /%,$(src)),$(src),$(srctree)/$(src)) |
15 | include $(if $(wildcard $(kbuild-dir)/Kbuild), $(kbuild-dir)/Kbuild, $(kbuild-dir)/Makefile) | 17 | include $(if $(wildcard $(kbuild-dir)/Kbuild), $(kbuild-dir)/Kbuild, $(kbuild-dir)/Makefile) |
16 | 18 | ||
17 | include scripts/Kbuild.include | ||
18 | include scripts/Makefile.lib | 19 | include scripts/Makefile.lib |
19 | 20 | ||
20 | ifdef host-progs | 21 | ifdef host-progs |