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Diffstat (limited to 'Documentation/kbuild/makefiles.txt')
| -rw-r--r-- | Documentation/kbuild/makefiles.txt | 35 |
1 files changed, 8 insertions, 27 deletions
diff --git a/Documentation/kbuild/makefiles.txt b/Documentation/kbuild/makefiles.txt index 8da26c6dd886..f124be6e4c3a 100644 --- a/Documentation/kbuild/makefiles.txt +++ b/Documentation/kbuild/makefiles.txt @@ -154,13 +154,8 @@ more details, with real examples. Kbuild compiles all the $(obj-y) files. It then calls "$(AR) rcSTP" to merge these files into one built-in.a file. - This is a thin archive without a symbol table, which makes it - unsuitable as a linker input. - - The scripts/link-vmlinux.sh script later makes an aggregate - built-in.a with "${AR} rcsTP", which creates the thin archive - with a symbol table and an index, making it a valid input for - the final vmlinux link passes. + This is a thin archive without a symbol table. It will be later + linked into vmlinux by scripts/link-vmlinux.sh The order of files in $(obj-y) is significant. Duplicates in the lists are allowed: the first instance will be linked into @@ -504,23 +499,6 @@ more details, with real examples. In the above example, -Wno-unused-but-set-variable will be added to KBUILD_CFLAGS only if gcc really accepts it. - cc-version - cc-version returns a numerical version of the $(CC) compiler version. - The format is <major><minor> where both are two digits. So for example - gcc 3.41 would return 0341. - cc-version is useful when a specific $(CC) version is faulty in one - area, for example -mregparm=3 was broken in some gcc versions - even though the option was accepted by gcc. - - Example: - #arch/x86/Makefile - cflags-y += $(shell \ - if [ $(cc-version) -ge 0300 ] ; then \ - echo "-mregparm=3"; fi ;) - - In the above example, -mregparm=3 is only used for gcc version greater - than or equal to gcc 3.0. - cc-ifversion cc-ifversion tests the version of $(CC) and equals the fourth parameter if version expression is true, or the fifth (if given) if the version @@ -1296,9 +1274,12 @@ See subsequent chapter for the syntax of the Kbuild file. --- 7.4 mandatory-y - mandatory-y is essentially used by include/uapi/asm-generic/Kbuild.asm - to define the minimum set of headers that must be exported in - include/asm. + mandatory-y is essentially used by include/(uapi/)asm-generic/Kbuild.asm + to define the minimum set of ASM headers that all architectures must have. + + This works like optional generic-y. If a mandatory header is missing + in arch/$(ARCH)/include/(uapi/)/asm, Kbuild will automatically generate + a wrapper of the asm-generic one. The convention is to list one subdir per line and preferably in alphabetic order. |