Kbuild fixes for v5.6 (3rd)

- fix __uint128_t capability test in Kconfig when GCC that defaults
    to 32-bit is used to build the 64-bit kernel
 
  - suppress new noisy Clang warnings -Wpointer-to-enum-cast
 
  - move the namespace field in Module.symvers for the backward
    compatibility reason for the depmod tool
 
  - use available compression for initramdisk when INTRAMFS_SOURCE
    is defined, which was the original behavior
 
  - fix modpost to handle correct large section numbers when it refers
    to modversion CRCs and module namespaces
 
  - fix comments and documents
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Merge tag 'kbuild-fixes-v5.6-3' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

Pull Kbuild fixes from Masahiro Yamada:

 - fix __uint128_t capability test in Kconfig when GCC that defaults to
   32-bit is used to build the 64-bit kernel

 - suppress new noisy Clang warnings -Wpointer-to-enum-cast

 - move the namespace field in Module.symvers for the backward
   compatibility reason for the depmod tool

 - use available compression for initramdisk when INTRAMFS_SOURCE is
   defined, which was the original behavior

 - fix modpost to handle correct large section numbers when it refers to
   modversion CRCs and module namespaces

 - fix comments and documents

* tag 'kbuild-fixes-v5.6-3' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
  scripts/kallsyms: fix wrong kallsyms_relative_base
  modpost: Get proper section index by get_secindex() instead of st_shndx
  initramfs: restore default compression behavior
  modpost: move the namespace field in Module.symvers last
  kbuild: Disable -Wpointer-to-enum-cast
  kbuild: doc: fix references to other documents
  int128: fix __uint128_t compiler test in Kconfig
  kconfig: introduce m32-flag and m64-flag
  kbuild: Fix inconsistent comment

Documentation/kbuild/kbuild.rst

@@ -237,7 +237,7 @@ This is solely useful to speed up test compiles.
 KBUILD_EXTRA_SYMBOLS
 --------------------
 For modules that use symbols from other modules.
-See more details in modules.txt.
+See more details in modules.rst.
 
 ALLSOURCE_ARCHS
 ---------------

Documentation/kbuild/kconfig-macro-language.rst

@@ -44,7 +44,7 @@ intermediate::
             def_bool y
 
 Then, Kconfig moves onto the evaluation stage to resolve inter-symbol
-dependency as explained in kconfig-language.txt.
+dependency as explained in kconfig-language.rst.
 
 
 Variables

Documentation/kbuild/makefiles.rst

@@ -924,7 +924,7 @@ When kbuild executes, the following steps are followed (roughly):
 	$(KBUILD_AFLAGS_MODULE) is used to add arch-specific options that
 	are used for assembler.
 
-	From commandline AFLAGS_MODULE shall be used (see kbuild.txt).
+	From commandline AFLAGS_MODULE shall be used (see kbuild.rst).
 
     KBUILD_CFLAGS_KERNEL
 	$(CC) options specific for built-in
@@ -937,7 +937,7 @@ When kbuild executes, the following steps are followed (roughly):
 
 	$(KBUILD_CFLAGS_MODULE) is used to add arch-specific options that
 	are used for $(CC).
-	From commandline CFLAGS_MODULE shall be used (see kbuild.txt).
+	From commandline CFLAGS_MODULE shall be used (see kbuild.rst).
 
     KBUILD_LDFLAGS_MODULE
 	Options for $(LD) when linking modules
@@ -945,7 +945,7 @@ When kbuild executes, the following steps are followed (roughly):
 	$(KBUILD_LDFLAGS_MODULE) is used to add arch-specific options
 	used when linking modules. This is often a linker script.
 
-	From commandline LDFLAGS_MODULE shall be used (see kbuild.txt).
+	From commandline LDFLAGS_MODULE shall be used (see kbuild.rst).
 
     KBUILD_LDS
 

Documentation/kbuild/modules.rst

@@ -470,9 +470,9 @@ build.
 
 	The syntax of the Module.symvers file is::
 
-	<CRC>       <Symbol>          <Namespace>  <Module>                         <Export Type>
+	<CRC>       <Symbol>         <Module>                         <Export Type>     <Namespace>
 
-	0xe1cc2a05  usb_stor_suspend  USB_STORAGE  drivers/usb/storage/usb-storage  EXPORT_SYMBOL_GPL
+	0xe1cc2a05  usb_stor_suspend drivers/usb/storage/usb-storage  EXPORT_SYMBOL_GPL USB_STORAGE
 
 	The fields are separated by tabs and values may be empty (e.g.
 	if no namespace is defined for an exported symbol).

Makefile

@@ -1804,7 +1804,7 @@ existing-targets := $(wildcard $(sort $(targets)))
 
 -include $(foreach f,$(existing-targets),$(dir $(f)).$(notdir $(f)).cmd)
 
-endif # config-targets
+endif # config-build
 endif # mixed-build
 endif # need-sub-make
 

init/Kconfig

@@ -767,8 +767,7 @@ config ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
 	bool
 
 config CC_HAS_INT128
-	def_bool y
-	depends on !$(cc-option,-D__SIZEOF_INT128__=0)
+	def_bool !$(cc-option,$(m64-flag) -D__SIZEOF_INT128__=0) && 64BIT
 
 #
 # For architectures that know their GCC __int128 support is sound

scripts/Kconfig.include

@@ -44,3 +44,10 @@ $(error-if,$(success, $(LD) -v | grep -q gold), gold linker '$(LD)' not supporte
 
 # gcc version including patch level
 gcc-version := $(shell,$(srctree)/scripts/gcc-version.sh $(CC))
+
+# machine bit flags
+#  $(m32-flag): -m32 if the compiler supports it, or an empty string otherwise.
+#  $(m64-flag): -m64 if the compiler supports it, or an empty string otherwise.
+cc-option-bit = $(if-success,$(CC) -Werror $(1) -E -x c /dev/null -o /dev/null,$(1))
+m32-flag := $(cc-option-bit,-m32)
+m64-flag := $(cc-option-bit,-m64)

scripts/Makefile.extrawarn

@@ -48,6 +48,7 @@ KBUILD_CFLAGS += -Wno-initializer-overrides
 KBUILD_CFLAGS += -Wno-format
 KBUILD_CFLAGS += -Wno-sign-compare
 KBUILD_CFLAGS += -Wno-format-zero-length
+KBUILD_CFLAGS += $(call cc-disable-warning, pointer-to-enum-cast)
 endif
 
 endif

scripts/export_report.pl

@@ -94,7 +94,7 @@ if (defined $opt{'o'}) {
 #
 while ( <$module_symvers> ) {
 	chomp;
-	my (undef, $symbol, $namespace, $module, $gpl) = split('\t');
+	my (undef, $symbol, $module, $gpl, $namespace) = split('\t');
 	$SYMBOL { $symbol } =  [ $module , "0" , $symbol, $gpl];
 }
 close($module_symvers);

scripts/kallsyms.c

@@ -195,13 +195,13 @@ static struct sym_entry *read_symbol(FILE *in)
 		return NULL;
 	}
 
-	if (is_ignored_symbol(name, type))
-		return NULL;
-
-	/* Ignore most absolute/undefined (?) symbols. */
 	if (strcmp(name, "_text") == 0)
 		_text = addr;
 
+	/* Ignore most absolute/undefined (?) symbols. */
+	if (is_ignored_symbol(name, type))
+		return NULL;
+
 	check_symbol_range(name, addr, text_ranges, ARRAY_SIZE(text_ranges));
 	check_symbol_range(name, addr, &percpu_range, 1);
 

scripts/mod/modpost.c

@@ -308,7 +308,8 @@ static const char *sec_name(struct elf_info *elf, int secindex)
 
 static void *sym_get_data(const struct elf_info *info, const Elf_Sym *sym)
 {
-	Elf_Shdr *sechdr = &info->sechdrs[sym->st_shndx];
+	unsigned int secindex = get_secindex(info, sym);
+	Elf_Shdr *sechdr = &info->sechdrs[secindex];
 	unsigned long offset;
 
 	offset = sym->st_value;
@@ -2427,7 +2428,7 @@ static void write_if_changed(struct buffer *b, const char *fname)
 }
 
 /* parse Module.symvers file. line format:
- * 0x12345678<tab>symbol<tab>module[[<tab>export]<tab>something]
+ * 0x12345678<tab>symbol<tab>module<tab>export<tab>namespace
  **/
 static void read_dump(const char *fname, unsigned int kernel)
 {
@@ -2440,7 +2441,7 @@ static void read_dump(const char *fname, unsigned int kernel)
 		return;
 
 	while ((line = get_next_line(&pos, file, size))) {
-		char *symname, *namespace, *modname, *d, *export, *end;
+		char *symname, *namespace, *modname, *d, *export;
 		unsigned int crc;
 		struct module *mod;
 		struct symbol *s;
@@ -2448,16 +2449,16 @@ static void read_dump(const char *fname, unsigned int kernel)
 		if (!(symname = strchr(line, '\t')))
 			goto fail;
 		*symname++ = '\0';
-		if (!(namespace = strchr(symname, '\t')))
-			goto fail;
-		*namespace++ = '\0';
-		if (!(modname = strchr(namespace, '\t')))
+		if (!(modname = strchr(symname, '\t')))
 			goto fail;
 		*modname++ = '\0';
-		if ((export = strchr(modname, '\t')) != NULL)
-			*export++ = '\0';
-		if (export && ((end = strchr(export, '\t')) != NULL))
-			*end = '\0';
+		if (!(export = strchr(modname, '\t')))
+			goto fail;
+		*export++ = '\0';
+		if (!(namespace = strchr(export, '\t')))
+			goto fail;
+		*namespace++ = '\0';
+
 		crc = strtoul(line, &d, 16);
 		if (*symname == '\0' || *modname == '\0' || *d != '\0')
 			goto fail;
@@ -2508,9 +2509,9 @@ static void write_dump(const char *fname)
 				namespace = symbol->namespace;
 				buf_printf(&buf, "0x%08x\t%s\t%s\t%s\t%s\n",
 					   symbol->crc, symbol->name,
-					   namespace ? namespace : "",
 					   symbol->module->name,
-					   export_str(symbol->export));
+					   export_str(symbol->export),
+					   namespace ? namespace : "");
 			}
 			symbol = symbol->next;
 		}

usr/Kconfig

@@ -124,17 +124,6 @@ choice
 
 	  If in doubt, select 'None'
 
-config INITRAMFS_COMPRESSION_NONE
-	bool "None"
-	help
-	  Do not compress the built-in initramfs at all. This may sound wasteful
-	  in space, but, you should be aware that the built-in initramfs will be
-	  compressed at a later stage anyways along with the rest of the kernel,
-	  on those architectures that support this. However, not compressing the
-	  initramfs may lead to slightly higher memory consumption during a
-	  short time at boot, while both the cpio image and the unpacked
-	  filesystem image will be present in memory simultaneously
-
 config INITRAMFS_COMPRESSION_GZIP
 	bool "Gzip"
 	depends on RD_GZIP
@@ -207,4 +196,15 @@ config INITRAMFS_COMPRESSION_LZ4
 	  If you choose this, keep in mind that most distros don't provide lz4
 	  by default which could cause a build failure.
 
+config INITRAMFS_COMPRESSION_NONE
+	bool "None"
+	help
+	  Do not compress the built-in initramfs at all. This may sound wasteful
+	  in space, but, you should be aware that the built-in initramfs will be
+	  compressed at a later stage anyways along with the rest of the kernel,
+	  on those architectures that support this. However, not compressing the
+	  initramfs may lead to slightly higher memory consumption during a
+	  short time at boot, while both the cpio image and the unpacked
+	  filesystem image will be present in memory simultaneously
+
 endchoice