Kbuild fixes for v5.5

- fix warning in out-of-tree 'make clean'
 
  - add READELF variable to the top Makefile
 
  - fix broken builds when LINUX_COMPILE_BY contains a backslash
 
  - fix build warning in kallsyms
 
  - fix NULL pointer access in expr_eq() in Kconfig
 
  - fix missing dependency on rsync in deb-pkg build
 
  - remove ---help--- from documentation
 
  - fix misleading documentation about directory descending
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Merge tag 'kbuild-fixes-v5.5' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

Pull Kbuild fixes from Masahiro Yamada:

 - fix warning in out-of-tree 'make clean'

 - add READELF variable to the top Makefile

 - fix broken builds when LINUX_COMPILE_BY contains a backslash

 - fix build warning in kallsyms

 - fix NULL pointer access in expr_eq() in Kconfig

 - fix missing dependency on rsync in deb-pkg build

 - remove ---help--- from documentation

 - fix misleading documentation about directory descending

* tag 'kbuild-fixes-v5.5' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
  kbuild: clarify the difference between obj-y and obj-m w.r.t. descending
  kconfig: remove ---help--- from documentation
  scripts: package: mkdebian: add missing rsync dependency
  kconfig: don't crash on NULL expressions in expr_eq()
  scripts/kallsyms: fix offset overflow of kallsyms_relative_base
  mkcompile_h: use printf for LINUX_COMPILE_BY
  mkcompile_h: git rid of UTS_TRUNCATE from LINUX_COMPILE_{BY,HOST}
  x86/boot: kbuild: allow readelf executable to be specified
  kbuild: fix 'No such file or directory' warning when cleaning
This commit is contained in:
Linus Torvalds 2019-12-21 10:49:47 -08:00
commit 6c1c79a5f4
9 changed files with 48 additions and 37 deletions

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@ -196,14 +196,11 @@ applicable everywhere (see syntax).
or equal to the first symbol and smaller than or equal to the second
symbol.
- help text: "help" or "---help---"
- help text: "help"
This defines a help text. The end of the help text is determined by
the indentation level, this means it ends at the first line which has
a smaller indentation than the first line of the help text.
"---help---" and "help" do not differ in behaviour, "---help---" is
used to help visually separate configuration logic from help within
the file as an aid to developers.
- misc options: "option" <symbol>[=<value>]

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@ -297,9 +297,19 @@ more details, with real examples.
If CONFIG_EXT2_FS is set to either 'y' (built-in) or 'm' (modular)
the corresponding obj- variable will be set, and kbuild will descend
down in the ext2 directory.
Kbuild only uses this information to decide that it needs to visit
the directory, it is the Makefile in the subdirectory that
specifies what is modular and what is built-in.
Kbuild uses this information not only to decide that it needs to visit
the directory, but also to decide whether or not to link objects from
the directory into vmlinux.
When Kbuild descends into the directory with 'y', all built-in objects
from that directory are combined into the built-in.a, which will be
eventually linked into vmlinux.
When Kbuild descends into the directory with 'm', in contrast, nothing
from that directory will be linked into vmlinux. If the Makefile in
that directory specifies obj-y, those objects will be left orphan.
It is very likely a bug of the Makefile or of dependencies in Kconfig.
It is good practice to use a `CONFIG_` variable when assigning directory
names. This allows kbuild to totally skip the directory if the

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@ -414,6 +414,7 @@ STRIP = $(CROSS_COMPILE)strip
OBJCOPY = $(CROSS_COMPILE)objcopy
OBJDUMP = $(CROSS_COMPILE)objdump
OBJSIZE = $(CROSS_COMPILE)size
READELF = $(CROSS_COMPILE)readelf
PAHOLE = pahole
LEX = flex
YACC = bison
@ -472,7 +473,7 @@ GCC_PLUGINS_CFLAGS :=
CLANG_FLAGS :=
export ARCH SRCARCH CONFIG_SHELL BASH HOSTCC KBUILD_HOSTCFLAGS CROSS_COMPILE AS LD CC
export CPP AR NM STRIP OBJCOPY OBJDUMP OBJSIZE PAHOLE LEX YACC AWK INSTALLKERNEL
export CPP AR NM STRIP OBJCOPY OBJDUMP OBJSIZE READELF PAHOLE LEX YACC AWK INSTALLKERNEL
export PERL PYTHON PYTHON2 PYTHON3 CHECK CHECKFLAGS MAKE UTS_MACHINE HOSTCXX
export KBUILD_HOSTCXXFLAGS KBUILD_HOSTLDFLAGS KBUILD_HOSTLDLIBS LDFLAGS_MODULE

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@ -103,7 +103,7 @@ vmlinux-objs-$(CONFIG_EFI_MIXED) += $(obj)/efi_thunk_$(BITS).o
quiet_cmd_check_data_rel = DATAREL $@
define cmd_check_data_rel
for obj in $(filter %.o,$^); do \
${CROSS_COMPILE}readelf -S $$obj | grep -qF .rel.local && { \
$(READELF) -S $$obj | grep -qF .rel.local && { \
echo "error: $$obj has data relocations!" >&2; \
exit 1; \
} || true; \

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@ -310,6 +310,15 @@ static void output_label(const char *label)
printf("%s:\n", label);
}
/* Provide proper symbols relocatability by their '_text' relativeness. */
static void output_address(unsigned long long addr)
{
if (_text <= addr)
printf("\tPTR\t_text + %#llx\n", addr - _text);
else
printf("\tPTR\t_text - %#llx\n", _text - addr);
}
/* uncompress a compressed symbol. When this function is called, the best table
* might still be compressed itself, so the function needs to be recursive */
static int expand_symbol(const unsigned char *data, int len, char *result)
@ -360,19 +369,6 @@ static void write_src(void)
printf("\t.section .rodata, \"a\"\n");
/* Provide proper symbols relocatability by their relativeness
* to a fixed anchor point in the runtime image, either '_text'
* for absolute address tables, in which case the linker will
* emit the final addresses at build time. Otherwise, use the
* offset relative to the lowest value encountered of all relative
* symbols, and emit non-relocatable fixed offsets that will be fixed
* up at runtime.
*
* The symbol names cannot be used to construct normal symbol
* references as the list of symbols contains symbols that are
* declared static and are private to their .o files. This prevents
* .tmp_kallsyms.o or any other object from referencing them.
*/
if (!base_relative)
output_label("kallsyms_addresses");
else
@ -380,6 +376,13 @@ static void write_src(void)
for (i = 0; i < table_cnt; i++) {
if (base_relative) {
/*
* Use the offset relative to the lowest value
* encountered of all relative symbols, and emit
* non-relocatable fixed offsets that will be fixed
* up at runtime.
*/
long long offset;
int overflow;
@ -402,12 +405,7 @@ static void write_src(void)
}
printf("\t.long\t%#x\n", (int)offset);
} else if (!symbol_absolute(&table[i])) {
if (_text <= table[i].addr)
printf("\tPTR\t_text + %#llx\n",
table[i].addr - _text);
else
printf("\tPTR\t_text - %#llx\n",
_text - table[i].addr);
output_address(table[i].addr);
} else {
printf("\tPTR\t%#llx\n", table[i].addr);
}
@ -416,7 +414,7 @@ static void write_src(void)
if (base_relative) {
output_label("kallsyms_relative_base");
printf("\tPTR\t_text - %#llx\n", _text - relative_base);
output_address(relative_base);
printf("\n");
}

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@ -254,6 +254,13 @@ static int expr_eq(struct expr *e1, struct expr *e2)
{
int res, old_count;
/*
* A NULL expr is taken to be yes, but there's also a different way to
* represent yes. expr_is_yes() checks for either representation.
*/
if (!e1 || !e2)
return expr_is_yes(e1) && expr_is_yes(e2);
if (e1->type != e2->type)
return 0;
switch (e1->type) {

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@ -55,12 +55,10 @@ CONFIG_FLAGS=""
if [ -n "$SMP" ] ; then CONFIG_FLAGS="SMP"; fi
if [ -n "$PREEMPT" ] ; then CONFIG_FLAGS="$CONFIG_FLAGS PREEMPT"; fi
if [ -n "$PREEMPT_RT" ] ; then CONFIG_FLAGS="$CONFIG_FLAGS PREEMPT_RT"; fi
UTS_VERSION="$UTS_VERSION $CONFIG_FLAGS $TIMESTAMP"
# Truncate to maximum length
UTS_LEN=64
UTS_TRUNCATE="cut -b -$UTS_LEN"
UTS_VERSION="$(echo $UTS_VERSION $CONFIG_FLAGS $TIMESTAMP | cut -b -$UTS_LEN)"
# Generate a temporary compile.h
@ -69,10 +67,10 @@ UTS_TRUNCATE="cut -b -$UTS_LEN"
echo \#define UTS_MACHINE \"$ARCH\"
echo \#define UTS_VERSION \"`echo $UTS_VERSION | $UTS_TRUNCATE`\"
echo \#define UTS_VERSION \"$UTS_VERSION\"
echo \#define LINUX_COMPILE_BY \"`echo $LINUX_COMPILE_BY | $UTS_TRUNCATE`\"
echo \#define LINUX_COMPILE_HOST \"`echo $LINUX_COMPILE_HOST | $UTS_TRUNCATE`\"
printf '#define LINUX_COMPILE_BY "%s"\n' "$LINUX_COMPILE_BY"
echo \#define LINUX_COMPILE_HOST \"$LINUX_COMPILE_HOST\"
echo \#define LINUX_COMPILER \"`$CC -v 2>&1 | grep ' version ' | sed 's/[[:space:]]*$//'`\"
} > .tmpcompile

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@ -174,7 +174,7 @@ Source: $sourcename
Section: kernel
Priority: optional
Maintainer: $maintainer
Build-Depends: bc, kmod, cpio, bison, flex | flex:native $extra_build_depends
Build-Depends: bc, rsync, kmod, cpio, bison, flex | flex:native $extra_build_depends
Homepage: http://www.kernel.org/
Package: $packagename

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@ -91,7 +91,7 @@ endif
# asm-generic/*.h is used by asm/*.h, and should not be included directly
header-test- += asm-generic/%
extra-y := $(patsubst $(obj)/%.h,%.hdrtest, $(shell find $(obj) -name '*.h'))
extra-y := $(patsubst $(obj)/%.h,%.hdrtest, $(shell find $(obj) -name '*.h' 2>/dev/null))
quiet_cmd_hdrtest = HDRTEST $<
cmd_hdrtest = \