- 25 Nov, 2019 14 commits
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Masahiro Yamada authored
There is no more reason to check the return value of check_symbol_range(). Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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Masahiro Yamada authored
Collect the ignored patterns to is_ignored_symbol(). Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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Masahiro Yamada authored
Refactoring for shortening the code. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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Masahiro Yamada authored
Unless the address range matters, symbols can be ignored earlier, which avoids unneeded memory allocation. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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Masahiro Yamada authored
Add 'const' where a function does not write to the pointer dereferenes. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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Masahiro Yamada authored
The callers of this function expect (unsigned char *). I do not see a good reason to make this function return (void *). Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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Masahiro Yamada authored
You can do equivalent things with strspn(). I do not see noticeable performance difference. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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Masahiro Yamada authored
sym_entry::sym is (unsigned char *) instead of (char *) because kallsyms exploits the MSB for compression, and the characters are used as the index of token_profit array. However, it requires casting (unsigned char *) to (char *) in some places since standard library functions such as strcmp(), strlen() expect (char *). Introduce a new helper, sym_name(), which advances the given pointer by 1 and casts it to (char *). Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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Masahiro Yamada authored
l <= strlen(sym_name) is unnecessary for prefix matching. strncmp() will do. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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Masahiro Yamada authored
Since commit 6f00df24 ("[PATCH] Strip local symbols from kallsyms"), all symbols starting '$' are ignored. is_arm_mapping_symbol() particularly ignores $a, $t, etc. but it is redundant. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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Masahiro Yamada authored
Currently, record_relative_base() iterates over the entire table to find the minimum address, but it is not efficient because we sort the table anyway. After sort_symbol(), the table is sorted by address. (kallsyms parses the 'nm -n' output, so the data is already sorted by address, but this commit does not rely on it.) Move record_relative_base() after sort_symbols(), and take the first non-absolute symbol value. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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Masahiro Yamada authored
Currently, build_initial_tok_table() trims unused symbols, but it is called after sort_symbols(). It is not efficient to sort the huge table that contains unused entries. Shrink the table before sorting it. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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Masahiro Yamada authored
build_initial_tok_table() overwrites unused sym_entry to shrink the table size. Before the entry is overwritten, table[i].sym must be freed since it is malloc'ed data. This fixes the 'definitely lost' report from valgrind. I ran valgrind against x86_64_defconfig of v5.4-rc8 kernel, and here is the summary: [Before the fix] LEAK SUMMARY: definitely lost: 53,184 bytes in 2,874 blocks [After the fix] LEAK SUMMARY: definitely lost: 0 bytes in 0 blocks Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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Masahiro Yamada authored
This is not defined in the standard headers. #ifndef is unneeded. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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- 23 Nov, 2019 7 commits
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Masahiro Yamada authored
Commit 2dffd23f ("kbuild: make single target builds much faster") made the situation much better. To improve it even more, apply the similar idea to the top Makefile. Trim unrelated directories from build-dirs. The single build code must be moved above the 'descend' target. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Tested-by: Jens Axboe <axboe@kernel.dk>
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Masahiro Yamada authored
When 'exported twice' is warned, let sym_add_exported() return without updating the symbol info. This respects the previous export, which is ordered first in modules.order This simplifies the code too. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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Masahiro Yamada authored
Now that there is no overwrap between symbols from ELF files and ones from Module.symvers. So, the 'exported twice' warning should be reported irrespective of where the symbol in question came from. The exceptional case is external module; in some cases, we build an external module to provide a different version/variant of the corresponding in-kernel module, overriding the same set of exported symbols. You can see this use-case in upstream; tools/testing/nvdimm/libnvdimm.ko replaces drivers/nvdimm/libnvdimm.ko in order to link it against mocked version of core kernel symbols. So, let's relax the 'exported twice' warning when building external modules. The multiple export from external modules is warned only when the previous one is from vmlinux or itself. With this refactoring, the ugly preloading goes away. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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Masahiro Yamada authored
It is complicated to add mocked-up symbols for pre-handling CRC. Handle CRC after all the export symbols in the relevant module are registered. Call handle_modversion() after the handle_symbol() iteration. In some cases, I see atand-alone __crc_* without __ksymtab_*. For example, ARCH=arm allyesconfig produces __crc_ccitt_veneer and __crc_itu_t_veneer. I guess they come from crc_ccitt, crc_itu_t, respectively. Since __*_veneer are auto-generated symbols, just ignore them. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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Masahiro Yamada authored
This function handles not only modversions, but also unresolved symbols, export symbols, etc. Rename it to a more proper function name. While I was here, I also added the 'const' qualifier to *sym. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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Masahiro Yamada authored
Currently, namespace_from_kstrtabns() relies on the fact that namespace strings are recorded in the __ksymtab_strings section. Actually, it is coded in include/linux/export.h, but modpost does not need to hard-code the section name. Elf_Sym::st_shndx holds the index of the relevant section. Using it is a more portable way to get the namespace string. Make namespace_from_kstrtabns() simply call sym_get_data(), and delete the info->ksymtab_strings . While I was here, I added more 'const' qualifiers to pointers. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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Masahiro Yamada authored
When CONFIG_MODULE_REL_CRCS is enabled, the value of __crc_* is not an absolute value, but the address to the CRC data embedded in the .rodata section. Getting the data pointed by the symbol value is somewhat complex. Split it out into a new helper, sym_get_data(). I will reuse it to refactor namespace_from_kstrtabns() in the next commit. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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- 14 Nov, 2019 2 commits
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Masahiro Yamada authored
Currently, some sanity checks for uapi headers are done by scripts/headers_check.pl, which is wired up to the 'headers_check' target in the top Makefile. It is true compiling headers has better test coverage, but there are still several headers excluded from the compile test. I like to keep headers_check.pl for a while, but we can delete a lot of code by moving the build rule to usr/include/Makefile. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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Masahiro Yamada authored
There are both positive and negative options about this feature. At first, I thought it was a good idea, but actually Linus stated a negative opinion (https://lkml.org/lkml/2019/9/29/227). I admit it is ugly and annoying. The baseline I'd like to keep is the compile-test of uapi headers. (Otherwise, kernel developers have no way to ensure the correctness of the exported headers.) I will maintain a small build rule in usr/include/Makefile. Remove the other header test functionality. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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- 11 Nov, 2019 17 commits
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Masahiro Yamada authored
GNU Make manual says: $? The names of all the prerequisites that are newer than the target, with spaces between them. To reflect this, rename any-prereq to newer-prereqs, which is clearer and more intuitive. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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Masahiro Yamada authored
The incremental build of Linux kernel is pretty slow when lots of objects are compiled. The rebuild of allmodconfig may take a few minutes even when none of the objects needs to be rebuilt. The time-consuming part in the incremental build is the evaluation of if_changed* macros since they are used in the recipes to compile C and assembly source files into objects. I notice the following code in if_changed* is expensive: $(filter-out $(PHONY) $(wildcard $^),$^) In the incremental build, every object has its .*.cmd file, which contains the auto-generated list of included headers. So, $^ are expanded into the long list of the source file + included headers, and $(wildcard $^) checks whether they exist. It may not be clear why this check exists there. Here is the record of my research. [1] The first code addition into Kbuild This code dates back to 2002. It is the pre-git era. So, I copy-pasted it from the historical git tree. | commit 4a6db079 (HEAD) | Author: Kai Germaschewski <kai@tp1.ruhr-uni-bochum.de> | Date: Mon Jun 17 00:22:37 2002 -0500 | | kbuild: Handle removed headers | | New and old way to handle dependencies would choke when a file | #include'd by other files was removed, since the dependency on it was | still recorded, but since it was gone, make has no idea what to do about | it (and would complain with "No rule to make <file> ...") | | We now add targets for all the previously included files, so make will | just ignore them if they disappear. | | diff --git a/Rules.make b/Rules.make | index 6ef827d3df39..7db5301ea7db 100644 | --- a/Rules.make | +++ b/Rules.make | @@ -446,7 +446,7 @@ if_changed = $(if $(strip $? \ | # execute the command and also postprocess generated .d dependencies | # file | | -if_changed_dep = $(if $(strip $? \ | +if_changed_dep = $(if $(strip $? $(filter-out FORCE $(wildcard $^),$^)\ | $(filter-out $(cmd_$(1)),$(cmd_$@))\ | $(filter-out $(cmd_$@),$(cmd_$(1)))),\ | @set -e; \ | diff --git a/scripts/fixdep.c b/scripts/fixdep.c | index b5d7bee8efc7..db45bd1888c0 100644 | --- a/scripts/fixdep.c | +++ b/scripts/fixdep.c | @@ -292,7 +292,7 @@ void parse_dep_file(void *map, size_t len) | exit(1); | } | memcpy(s, m, p-m); s[p-m] = 0; | - printf("%s: \\\n", target); | + printf("deps_%s := \\\n", target); | m = p+1; | | clear_config(); | @@ -314,7 +314,8 @@ void parse_dep_file(void *map, size_t len) | } | m = p + 1; | } | - printf("\n"); | + printf("\n%s: $(deps_%s)\n\n", target, target); | + printf("$(deps_%s):\n", target); | } | | void print_deps(void) The "No rule to make <file> ..." error can be solved by passing -MP to the compiler, but I think the detection of header removal is a good feature. When a header is removed, all source files that previously included it should be re-compiled. This makes sure we has correctly got rid of #include directives of it. This is also related with the behavior of $?. The GNU Make manual says: $? The names of all the prerequisites that are newer than the target, with spaces between them. This does not explain whether a non-existent prerequisite is considered to be newer than the target. At this point of time, GNU Make 3.7x was used, where the $? did not include non-existent prerequisites. Therefore, $(filter-out FORCE $(wildcard $^),$^) was useful to detect the header removal, and to rebuild the related objects if it is the case. [2] Change of $? behavior Later, the behavior of $? was changed (fixed) to include prerequisites that did not exist. First, GNU Make commit 64e16d6c00a5 ("Various changes getting ready for the release of 3.81.") changed it, but in the release test of 3.81, it turned out to break the kernel build. See these: - http://lists.gnu.org/archive/html/bug-make/2006-03/msg00003.html - https://savannah.gnu.org/bugs/?16002 - https://savannah.gnu.org/bugs/?16051 Then, GNU Make commit 6d8d9b74d9c5 ("Numerous updates to tests for issues found on Cygwin and Windows.") reverted it for the 3.81 release to give Linux kernel time to adjust to the new behavior. After the 3.81 release, GNU Make commit 7595f38f62af ("Fixed a number of documentation bugs, plus some build/install issues:") re-added it. [3] Adjustment to the new $? behavior on Kbuild side Meanwhile, the kernel build was changed by commit 4f193362 ("kbuild: change kbuild to not rely on incorrect GNU make behavior") to adjust to the new $? behavior. [4] GNU Make 3.82 released in 2010 GNU Make 3.82 was the first release that integrated the correct $? behavior. At this point, Kbuild dealt with GNU Make versions with different $? behaviors. 3.81 or older: $? does not contain any non-existent prerequisite. $(filter-out $(PHONY) $(wildcard $^),$^) was useful to detect removed include headers. 3.82 or newer: $? contains non-existent prerequisites. When a header is removed, it appears in $?. $(filter-out $(PHONY) $(wildcard $^),$^) became a redundant check. With the correct $? behavior, we could have dropped the expensive check for 3.82 or later, but we did not. (Maybe nobody noticed this optimization.) [5] The .SECONDARY special target trips up $? Some time later, I noticed $? did not work as expected under some circumstances. As above, $? should contain non-existent prerequisites, but the ones specified as SECONDARY do not appear in $?. I asked this in GNU Make ML, and it seems a bug: https://lists.gnu.org/archive/html/bug-make/2019-01/msg00001.html Since commit 8e9b61b2 ("kbuild: move .SECONDARY special target to Kbuild.include"), all files, including headers listed in .*.cmd files, are treated as secondary. So, we are back into the incorrect $? behavior. If we Kbuild want to react to the header removal, we need to keep $(filter-out $(PHONY) $(wildcard $^),$^) but this makes the rebuild so slow. [Summary] - I believe noticing the header removal and recompiling related objects is a nice feature for the build system. - If $? worked correctly, $(filter-out $(PHONY),$?) would be enough to detect the header removal. - Currently, $? does not work correctly when used with .SECONDARY, and Kbuild is hit by this bug. - I filed a bug report for this, but not fixed yet as of writing. - Currently, the header removal is detected by the following expensive code: $(filter-out $(PHONY) $(wildcard $^),$^) - I do not want to revert commit 8e9b61b2 ("kbuild: move .SECONDARY special target to Kbuild.include"). Specifying .SECONDARY globally is clean, and it matches to the Kbuild policy. This commit proactively removes the expensive check since it makes the incremental build faster. A downside is Kbuild will no longer be able to notice the header removal. You can confirm it by the full-build followed by a header removal, and then re-build. $ make defconfig all [ full build ] $ rm include/linux/device.h $ make CALL scripts/checksyscalls.sh CALL scripts/atomic/check-atomics.sh DESCEND objtool CHK include/generated/compile.h Kernel: arch/x86/boot/bzImage is ready (#11) Building modules, stage 2. MODPOST 12 modules Previously, Kbuild noticed a missing header and emits a build error. Now, Kbuild is fine with it. This is an unusual corner-case, not a big deal. Once the $? bug is fixed in GNU Make, everything will work fine. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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Masahiro Yamada authored
Since commit 707816c8 ("netfilter: remove deprecation warnings from uapi headers."), you can compile linux/netfilter_ipv4/ipt_LOG.h and linux/netfilter_ipv6/ip6t_LOG.h without warnings. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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Masahiro Yamada authored
The local variable, ns_entry, is unneeded. While I was here, I also cleaned up the comparison with NULL or 0. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Reviewed-by: Matthias Maennich <maennich@google.com>
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Masahiro Yamada authored
scripts/nsdeps is written to take care of only in-tree modules. Perhaps, this is not a bug, but just a design. At least, Documentation/core-api/symbol-namespaces.rst focuses on in-tree modules. Having said that, some people already tried nsdeps for external modules. So, it would be nice to support it. Reported-by: Steve French <smfrench@gmail.com> Reported-by: Jessica Yu <jeyu@kernel.org> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Tested-by: Jessica Yu <jeyu@kernel.org> Acked-by: Jessica Yu <jeyu@kernel.org> Reviewed-by: Matthias Maennich <maennich@google.com> Tested-by: Matthias Maennich <maennich@google.com>
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Masahiro Yamada authored
The modpost, with the -d option given, generates per-module .ns_deps files. Kbuild generates per-module .mod files to carry module information. This is convenient because Make handles multiple jobs in parallel when the -j option is given. On the other hand, the modpost always runs as a single thread. I do not see a strong reason to produce separate .ns_deps files. This commit changes the modpost to generate just one file, modules.nsdeps, each line of which has the following format: <module_name>: <list of missing namespaces> Please note it contains *missing* namespaces instead of required ones. So, modules.nsdeps is empty if the namespace dependency is all good. This will work more efficiently because spatch will no longer process already imported namespaces. I removed the '(if needed)' from the nsdeps log since spatch is invoked only when needed. This also solves the stale .ns_deps problem reported by Jessica Yu: https://lkml.org/lkml/2019/10/28/467Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Tested-by: Jessica Yu <jeyu@kernel.org> Acked-by: Jessica Yu <jeyu@kernel.org> Reviewed-by: Matthias Maennich <maennich@google.com> Tested-by: Matthias Maennich <maennich@google.com>
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Masahiro Yamada authored
buf_write() allocates memory. Free it. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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Masahiro Yamada authored
'make nsdeps' invokes the modpost three times at most; before linking vmlinux, before building modules, and finally for generating .ns_deps files. Running the modpost again and again is not efficient. The last two can be unified. When the -d option is given, the modpost still does the usual job, and in addition, generates .ns_deps files. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Tested-by: Matthias Maennich <maennich@google.com> Reviewed-by: Matthias Maennich <maennich@google.com>
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Bhaskar Chowdhury authored
Signed-off-by: Bhaskar Chowdhury <unixbhaskar@gmail.com> Acked-by: Alexander Kapshuk <alexander.kapshuk@gmail.com> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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Alyssa Ross authored
If ncurses is installed, but at a non-default location, the previous error message was not helpful in resolving the situation. Now it will suggest that pkg-config might need to be installed in addition to ncurses. Signed-off-by: Alyssa Ross <hi@alyssa.is> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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Laura Abbott authored
make listnewconfig will list the individual options that need to be set. This is useful but there's no easy way to get the help text associated with the options at the same time. Introduce a new targe 'make helpnewconfig' which lists the full help text of all the new options as well. This makes it easier to automatically generate changes that are easy for humans to review. This command also adds markers between each option for easier parsing. Signed-off-by: Laura Abbott <labbott@redhat.com> Acked-by: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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Matteo Croce authored
Add a 'dir-pkg' target which just creates the same directory structures as in tar-pkg, but doesn't package anything. Useful when the user wants to copy the kernel tree on a machine using ssh, rsync or whatever. Signed-off-by: Matteo Croce <mcroce@redhat.com> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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Geert Uytterhoeven authored
There are 6 defconfigs with names longer than 24 characters, breaking alignment in "make help". The "winner" is "ecovec24-romimage_defconfig", counting in at 27 characters. Extend the defconfig field size to 27 to restore alignment. Don't use a larger value, to not encourage people to create even longer defconfig names. Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Acked-by: Hans-Christian Egtvedt <egtvedt@samfundet.no> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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Geert Uytterhoeven authored
Some "make help" text lines extend beyond 80 characters. Wrap them before an opening parenthesis, or before 80 characters. Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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Bhaskar Chowdhury authored
This patch replaces backquote to dollar parenthesis syntax for better readability. Signed-off-by: Bhaskar Chowdhury <unixbhaskar@gmail.com> Acked-by: Randy Dunlap <rdunlap@infradead.org> Acked-by: Nico Schottelius <nico-linuxsetlocalversion@schottelius.org> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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Masahiro Yamada authored
EXPORT_SYMBOL from assembly code produces an unused symbol __kcrctab_*. kcrctab is used as a section name (prefixed with three underscores), but never used as a symbol. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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Masahiro Yamada authored
For EXPORT_SYMBOL from C files, <linux/export.h> defines __ksymtab_* as local symbols. For EXPORT_SYMBOL from assembly, in contrast, <asm-generic/export.h> produces globally-visible __ksymtab_* symbols due to this .globl directive. I do not know why this must be global. It still works without this. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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