> On Feb 1, 2023, at 11:23 PM, Christophe Leroy <christophe.leroy@xxxxxxxxxx> wrote: > > > > Le 01/02/2023 à 23:32, Song Liu a écrit : >> module_layout manages different types of memory (text, data, rodata, etc.) >> in one allocation, which is problematic for some reasons: >> >> 1. It is hard to enable CONFIG_STRICT_MODULE_RWX. >> 2. It is hard to use huge pages in modules (and not break strict rwx). >> 3. Many archs uses module_layout for arch-specific data, but it is not >> obvious how these data are used (are they RO, RX, or RW?) >> >> Improve the scenario by replacing 2 (or 3) module_layout per module with >> up to 7 module_memory per module: >> >> MOD_TEXT, >> MOD_DATA, >> MOD_RODATA, >> MOD_RO_AFTER_INIT, >> MOD_INIT_TEXT, >> MOD_INIT_DATA, >> MOD_INIT_RODATA, >> >> and allocating them separately. This adds slightly more entries to >> mod_tree (from up to 3 entries per module, to up to 7 entries per >> module). However, this at most adds a small constant overhead to >> __module_address(), which is expected to be fast. >> >> Various archs use module_layout for different data. These data are put >> into different module_memory based on their location in module_layout. >> IOW, data that used to go with text is allocated with MOD_MEM_TYPE_TEXT; >> data that used to go with data is allocated with MOD_MEM_TYPE_DATA, etc. >> >> module_memory simplifies quite some of the module code. For example, >> ARCH_WANTS_MODULES_DATA_IN_VMALLOC is a lot cleaner, as it just uses a >> different allocator for the data. kernel/module/strict_rwx.c is also >> much cleaner with module_memory. >> >> Signed-off-by: Song Liu <song@xxxxxxxxxx> >> Cc: Luis Chamberlain <mcgrof@xxxxxxxxxx> >> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> >> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> >> Cc: Guenter Roeck <linux@xxxxxxxxxxxx> >> Cc: Christophe Leroy <christophe.leroy@xxxxxxxxxx> >> > > CALL scripts/checksyscalls.sh > CC kernel/module/main.o > kernel/module/main.c: In function 'mod_mem_use_vmalloc': > kernel/module/main.c:1175:16: error: implicit declaration of function > 'mod_mem_is_core_data'; did you mean 'mod_mem_type_is_core_data'? > [-Werror=implicit-function-declaration] > 1175 | return mod_mem_is_core_data(type); > | ^~~~~~~~~~~~~~~~~~~~ > | mod_mem_type_is_core_data > cc1: some warnings being treated as errors > make[3]: *** [scripts/Makefile.build:252: kernel/module/main.o] Error 1 > make[2]: *** [scripts/Makefile.build:504: kernel/module] Error 2 > make[1]: *** [scripts/Makefile.build:504: kernel] Error 2 > make: *** [Makefile:2024: .] Error 2 Oops.. Let me get this through build tests by kernel test bot. Thanks, Song
