Commit e81a2dab authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'kbuild-fixes-v6.6-2' of... 

Merge tag 'kbuild-fixes-v6.6-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

Pull Kbuild fixes from Masahiro Yamada:

 - Fix the module compression with xz so the in-kernel decompressor
   works

 - Document a kconfig idiom to express an optional dependency between
   modules

 - Make modpost, when W=1 is given, detect broken drivers that reference
   .exit.* sections

 - Remove unused code

* tag 'kbuild-fixes-v6.6-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
  kbuild: remove stale code for 'source' symlink in packaging scripts
  modpost: Don't let "driver"s reference .exit.*
  vmlinux.lds.h: remove unused CPU_KEEP and CPU_DISCARD macros
  modpost: add missing else to the "of" check
  Documentation: kbuild: explain handling optional dependencies
  kbuild: Use CRC32 and a 1MiB dictionary for XZ compressed modules
parents d2c52315 2d7d1bc1

Documentation/kbuild/kconfig-language.rst

+26 −0
Original line number Diff line number Diff line
@@ -573,6 +573,32 @@ above, leading to: 
	bool "Support for foo hardware"

	depends on ARCH_FOO_VENDOR || COMPILE_TEST



Optional dependencies

~~~~~~~~~~~~~~~~~~~~~



Some drivers are able to optionally use a feature from another module

or build cleanly with that module disabled, but cause a link failure

when trying to use that loadable module from a built-in driver.



The most common way to express this optional dependency in Kconfig logic

uses the slightly counterintuitive::



  config FOO

	tristate "Support for foo hardware"

	depends on BAR || !BAR



This means that there is either a dependency on BAR that disallows

the combination of FOO=y with BAR=m, or BAR is completely disabled.

For a more formalized approach if there are multiple drivers that have

the same dependency, a helper symbol can be used, like::



  config FOO

	tristate "Support for foo hardware"

	depends on BAR_OPTIONAL



  config BAR_OPTIONAL

	def_tristate BAR || !BAR



Kconfig recursive dependency limitations

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

include/asm-generic/vmlinux.lds.h

+0 −7
Original line number Diff line number Diff line
@@ -138,13 +138,6 @@ 
 * are handled as text/data or they can be discarded (which

 * often happens at runtime)

 */

#ifdef CONFIG_HOTPLUG_CPU

#define CPU_KEEP(sec)    *(.cpu##sec)

#define CPU_DISCARD(sec)

#else

#define CPU_KEEP(sec)

#define CPU_DISCARD(sec) *(.cpu##sec)

#endif



#if defined(CONFIG_MEMORY_HOTPLUG)

#define MEM_KEEP(sec)    *(.mem##sec)

scripts/Makefile.modinst

+1 −1
Original line number Diff line number Diff line
@@ -144,7 +144,7 @@ endif 
quiet_cmd_gzip = GZIP    $@

      cmd_gzip = $(KGZIP) -n -f $<

quiet_cmd_xz = XZ      $@

      cmd_xz = $(XZ) --lzma2=dict=2MiB -f $<

      cmd_xz = $(XZ) --check=crc32 --lzma2=dict=1MiB -f $<

quiet_cmd_zstd = ZSTD    $@

      cmd_zstd = $(ZSTD) -T0 --rm -f -q $<

scripts/mod/file2alias.c

+1 −1
Original line number Diff line number Diff line
@@ -1604,7 +1604,7 @@ void handle_moddevtable(struct module *mod, struct elf_info *info, 
	/* First handle the "special" cases */

	if (sym_is(name, namelen, "usb"))

		do_usb_table(symval, sym->st_size, mod);

	if (sym_is(name, namelen, "of"))

	else if (sym_is(name, namelen, "of"))

		do_of_table(symval, sym->st_size, mod);

	else if (sym_is(name, namelen, "pnp"))

		do_pnp_device_entry(symval, sym->st_size, mod);

scripts/mod/modpost.c

+13 −2
Original line number Diff line number Diff line
@@ -1015,9 +1015,20 @@ static int secref_whitelist(const char *fromsec, const char *fromsym, 
				    "*_console")))

		return 0;



	/* symbols in data sections that may refer to meminit/exit sections */

	/* symbols in data sections that may refer to meminit sections */

	if (match(fromsec, PATTERNS(DATA_SECTIONS)) &&

	    match(tosec, PATTERNS(ALL_XXXINIT_SECTIONS, ALL_EXIT_SECTIONS)) &&

	    match(tosec, PATTERNS(ALL_XXXINIT_SECTIONS, ALL_XXXEXIT_SECTIONS)) &&

	    match(fromsym, PATTERNS("*driver")))

		return 0;



	/*

	 * symbols in data sections must not refer to .exit.*, but there are

	 * quite a few offenders, so hide these unless for W=1 builds until

	 * these are fixed.

	 */

	if (!extra_warn &&

	    match(fromsec, PATTERNS(DATA_SECTIONS)) &&

	    match(tosec, PATTERNS(EXIT_SECTIONS)) &&

	    match(fromsym, PATTERNS("*driver")))

		return 0;