On Fri, Feb 3, 2023 at 1:45 PM Song Liu <song@xxxxxxxxxx> wrote: > > 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. This version passed build test by kernel test bot: https://lore.kernel.org/linux-raid/63df0daa.eKYOEelTitBUzF+e%25lkp@xxxxxxxxx/T/#u > > 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>> [...]
