kernel/linux.git/scripts/mod/modpost.c, branch linux-5.11.y

kbuild: generate Module.symvers only when vmlinux exists

2021-05-19T08:29:36+00:00

[ Upstream commit 69bc8d386aebbd91a6bb44b6d33f77c8dfa9ed8c ] The external module build shows the following warning if Module.symvers is missing in the kernel tree. WARNING: Symbol version dump "Module.symvers" is missing. Modules may not have dependencies or modversions. I think this is an important heads-up because the resulting modules may not work as expected. This happens when you did not build the entire kernel tree, for example, you might have prepared the minimal setups for external modules by 'make defconfig && make modules_preapre'. A problem is that 'make modules' creates Module.symvers even without vmlinux. In this case, that warning is suppressed since Module.symvers already exists in spite of its incomplete content. The incomplete (i.e. invalid) Module.symvers should not be created. This commit changes the second pass of modpost to dump symbols into modules-only.symvers. The final Module.symvers is created by concatenating vmlinux.symvers and modules-only.symvers if both exist. Module.symvers is supposed to collect symbols from both vmlinux and modules. It might be a bit confusing, and I am not quite sure if it is an official interface, but presumably it is difficult to rename it because some tools (e.g. kmod) parse it. Signed-off-by: Masahiro Yamada Signed-off-by: Sasha Levin

modpost: turn static exports into error

2020-12-21T04:57:08+00:00

Using EXPORT_SYMBOL*() on static functions is fundamentally wrong. Modpost currently reports that as a warning, but clearly this is not a pattern we should allow, and all in-tree occurences should have been fixed by now. So, promote the warn() message to error() to make sure this never happens again. Acked-by: Greg Kroah-Hartman Reviewed-by: Matthias Maennich Signed-off-by: Quentin Perret Signed-off-by: Masahiro Yamada

modpost: turn section mismatches to error from fatal()

2020-12-21T04:57:08+00:00

There is code that reports static EXPORT_SYMBOL a few lines below. It is not a good idea to bail out here. I renamed sec_mismatch_fatal to sec_mismatch_warn_only (with logical inversion) to match to CONFIG_SECTION_MISMATCH_WARN_ONLY. Signed-off-by: Masahiro Yamada

modpost: change license incompatibility to error() from fatal()

2020-12-21T04:57:08+00:00

Change fatal() to error() to continue running to report more possible issues. There is no difference in the fact that modpost will fail anyway. Signed-off-by: Masahiro Yamada

modpost: turn missing MODULE_LICENSE() into error

2020-12-21T04:57:08+00:00

Do not create modules with no license tag. Signed-off-by: Masahiro Yamada

modpost: refactor error handling and clarify error/fatal difference

2020-12-21T04:57:08+00:00

We have 3 log functions. fatal() is special because it lets modpost bail out immediately. The difference between warn() and error() is the only prefix parts ("WARNING:" vs "ERROR:"). In my understanding, the expected handling of error() is to propagate the return code of the function to the exit code of modpost, as check_exports() etc. already does. This is a good manner in general because we should display as many error messages as possible in a single run of modpost. What is annoying about fatal() is that it kills modpost at the first error. People would need to run Kbuild again and again until they fix all errors. But, unfortunately, people tend to do: "This case should not be allowed. Let's replace warn() with fatal()." One of the reasons is probably it is tedious to manually hoist the error code to the main() function. This commit refactors error() so any single call for it automatically makes modpost return the error code. I also added comments in modpost.h for warn(), error(), and fatal(). Please use fatal() only when you have a strong reason to do so. For example: - Memory shortage (i.e. malloc() etc. has failed) - The ELF file is broken, and there is no point to continue parsing - Something really odd has happened For general coding errors, please use error(). Signed-off-by: Masahiro Yamada Tested-by: Quentin Perret

modpost: rename merror() to error()

2020-12-21T04:57:08+00:00

The log function names, warn(), merror(), fatal() are inconsistent. Commit 2a11665945d5 ("kbuild: distinguish between errors and warnings in modpost") intentionally chose merror() to avoid the conflict with the library function error(). See man page of error(3). But, we are already causing the conflict with warn() because it is also a library function. See man page of warn(3). err() would be a problem for the same reason. The common technique to work around name conflicts is to use macros. For example: /* in a header */ #define error(fmt, ...) __error(fmt, ##__VA_ARGS__) #define warn(fmt, ...) __warn(fmt, ##__VA_ARGS__) /* function definition */ void __error(const char *fmt, ...) { } void __warn(const char *fmt, ...) { } In this way, we can implement our own warn() and error(), still we can include and with no problem. And, commit 93c95e526a4e ("modpost: rework and consolidate logging interface") already did that. Since the log functions are all macros, we can use error() without causing "conflicting types" errors. Signed-off-by: Masahiro Yamada

treewide: Convert macro and uses of section(foo) to section("foo")

2020-10-25T21:51:49+00:00

Use a more generic form for __section that requires quotes to avoid complications with clang and gcc differences. Remove the quote operator # from compiler_attributes.h __section macro. Convert all unquoted __section(foo) uses to quoted __section("foo"). Also convert __attribute__((section("foo"))) uses to __section("foo") even if the __attribute__ has multiple list entry forms. Conversion done using the script at: https://lore.kernel.org/lkml/75393e5ddc272dc7403de74d645e6c6e0f4e70eb.camel@perches.com/2-convert_section.pl Signed-off-by: Joe Perches Reviewed-by: Nick Desaulniers Reviewed-by: Miguel Ojeda Signed-off-by: Linus Torvalds

modpost: explain why we can't use strsep

2020-07-27T04:38:38+00:00

Mention why we open-code strsep, so it is clear that it is intentional. Fixes: 736bb11898ef ("modpost: remove use of non-standard strsep() in HOSTCC code") Signed-off-by: Wolfram Sang Signed-off-by: Masahiro Yamada

modpost: remove use of non-standard strsep() in HOSTCC code

2020-07-07T02:21:00+00:00

strsep() is neither standard C nor POSIX and used outside the kernel code here. Using it here requires that the build host supports it out of the box which is e.g. not true for a Darwin build host and using a cross-compiler. This leads to: scripts/mod/modpost.c:145:2: warning: implicit declaration of function 'strsep' [-Wimplicit-function-declaration] return strsep(stringp, "\n"); ^ and a segfault when running MODPOST. See also: https://stackoverflow.com/a/7219504 So let's replace this by strchr() instead of using strsep(). It does not hurt kernel size or speed since this code is run on the build host. Fixes: ac5100f5432967 ("modpost: add read_text_file() and get_line() helpers") Co-developed-by: Masahiro Yamada Signed-off-by: H. Nikolaus Schaller Signed-off-by: Masahiro Yamada

kernel/linux.git/scripts/mod/modpost.c, branch linux-5.11.y

kbuild: generate Module.symvers only when vmlinux exists

modpost: turn static exports into error

modpost: turn section mismatches to error from fatal()

modpost: change license incompatibility to error() from fatal()

modpost: turn missing MODULE_LICENSE() into error

modpost: refactor error handling and clarify error/fatal difference

modpost: rename merror() to error()

treewide: Convert macro and uses of __section(foo) to __section("foo")

modpost: explain why we can't use strsep

modpost: remove use of non-standard strsep() in HOSTCC code

treewide: Convert macro and uses of section(foo) to section("foo")