diff options
-rw-r--r-- | Documentation/kbuild/makefiles.txt | 53 |
1 files changed, 25 insertions, 28 deletions
diff --git a/Documentation/kbuild/makefiles.txt b/Documentation/kbuild/makefiles.txt index d77e24e0055d..31bfcbf958fc 100644 --- a/Documentation/kbuild/makefiles.txt +++ b/Documentation/kbuild/makefiles.txt | |||
@@ -285,45 +285,42 @@ more details, with real examples. | |||
285 | --- 3.7 Compilation flags | 285 | --- 3.7 Compilation flags |
286 | 286 | ||
287 | ccflags-y, asflags-y and ldflags-y | 287 | ccflags-y, asflags-y and ldflags-y |
288 | The three flags listed above applies only to the kbuild makefile | 288 | The three flags listed above apply only to the kbuild makefile where |
289 | where they are assigned. They are used for all the normal | 289 | they are assigned (i.e., per-directory). They are used for all the |
290 | cc, as and ld invocation happenign during a recursive build. | 290 | normal cc, as and ld invocation happening during a recursive build. |
291 | Note: Flags with the same behaviour were previously named: | 291 | Note: Flags with the same behaviour were previously named: |
292 | EXTRA_CFLAGS, EXTRA_AFLAGS and EXTRA_LDFLAGS. | 292 | EXTRA_CFLAGS, EXTRA_AFLAGS and EXTRA_LDFLAGS. They are still |
293 | They are yet supported but their use are deprecated. | 293 | supported but their use is deprecated. |
294 | 294 | ||
295 | ccflags-y specifies options for compiling C files with $(CC). | 295 | ccflags-y specifies options for compiling with $(CC). |
296 | 296 | ||
297 | Example: | 297 | Example: |
298 | # drivers/sound/emu10k1/Makefile | 298 | # drivers/acpi/Makefile |
299 | ccflags-y += -I$(obj) | 299 | ccflags-y := -Os |
300 | ccflags-$(DEBUG) += -DEMU10K1_DEBUG | 300 | ccflags-$(CONFIG_ACPI_DEBUG) += -DACPI_DEBUG_OUTPUT |
301 | |||
302 | 301 | ||
303 | This variable is necessary because the top Makefile owns the | 302 | This variable is necessary because the top Makefile owns the |
304 | variable $(KBUILD_CFLAGS) and uses it for compilation flags for the | 303 | variable $(KBUILD_CFLAGS) and uses it for compilation flags for the |
305 | entire tree. | 304 | entire tree. |
306 | 305 | ||
307 | asflags-y is a similar string for per-directory options | 306 | asflags-y specifies options for assembling with $(AS). |
308 | when compiling assembly language source. | ||
309 | 307 | ||
310 | Example: | 308 | Example: |
311 | #arch/x86_64/kernel/Makefile | 309 | #arch/sparc/kernel/Makefile |
312 | asflags-y := -traditional | 310 | asflags-y := -ansi |
313 | |||
314 | 311 | ||
315 | ldflags-y is a string for per-directory options to $(LD). | 312 | ldflags-y specifies options for linking with $(LD). |
316 | 313 | ||
317 | Example: | 314 | Example: |
318 | #arch/m68k/fpsp040/Makefile | 315 | #arch/cris/boot/compressed/Makefile |
319 | ldflags-y := -x | 316 | ldflags-y += -T $(srctree)/$(src)/decompress_$(arch-y).lds |
320 | 317 | ||
321 | subdir-ccflags-y, subdir-asflags-y | 318 | subdir-ccflags-y, subdir-asflags-y |
322 | The two flags listed above are similar to ccflags-y and as-falgs-y. | 319 | The two flags listed above are similar to ccflags-y and asflags-y. |
323 | The difference is that the subdir- variants has effect for the kbuild | 320 | The difference is that the subdir- variants affect the kbuild |
324 | file where tey are present and all subdirectories. | 321 | file where they are present and all subdirectories. Options specified |
325 | Options specified using subdir-* are added to the commandline before | 322 | using subdir-* are added to the commandline before the options |
326 | the options specified using the non-subdir variants. | 323 | specified using the non-subdir variants. |
327 | 324 | ||
328 | Example: | 325 | Example: |
329 | subdir-ccflags-y := -Werror | 326 | subdir-ccflags-y := -Werror |
@@ -341,18 +338,18 @@ more details, with real examples. | |||
341 | CFLAGS_aha152x.o = -DAHA152X_STAT -DAUTOCONF | 338 | CFLAGS_aha152x.o = -DAHA152X_STAT -DAUTOCONF |
342 | CFLAGS_gdth.o = # -DDEBUG_GDTH=2 -D__SERIAL__ -D__COM2__ \ | 339 | CFLAGS_gdth.o = # -DDEBUG_GDTH=2 -D__SERIAL__ -D__COM2__ \ |
343 | -DGDTH_STATISTICS | 340 | -DGDTH_STATISTICS |
344 | CFLAGS_seagate.o = -DARBITRATE -DPARITY -DSEAGATE_USE_ASM | ||
345 | 341 | ||
346 | These three lines specify compilation flags for aha152x.o, | 342 | These two lines specify compilation flags for aha152x.o and gdth.o. |
347 | gdth.o, and seagate.o | ||
348 | 343 | ||
349 | $(AFLAGS_$@) is a similar feature for source files in assembly | 344 | $(AFLAGS_$@) is a similar feature for source files in assembly |
350 | languages. | 345 | languages. |
351 | 346 | ||
352 | Example: | 347 | Example: |
353 | # arch/arm/kernel/Makefile | 348 | # arch/arm/kernel/Makefile |
354 | AFLAGS_head-armv.o := -DTEXTADDR=$(TEXTADDR) -traditional | 349 | AFLAGS_head.o := -DTEXT_OFFSET=$(TEXT_OFFSET) |
355 | AFLAGS_head-armo.o := -DTEXTADDR=$(TEXTADDR) -traditional | 350 | AFLAGS_crunch-bits.o := -Wa,-mcpu=ep9312 |
351 | AFLAGS_iwmmxt.o := -Wa,-mcpu=iwmmxt | ||
352 | |||
356 | 353 | ||
357 | --- 3.9 Dependency tracking | 354 | --- 3.9 Dependency tracking |
358 | 355 | ||