On Wed, Feb 08, 2023 at 09:37:21AM +0100, Thomas Gleixner wrote: > On Mon, Feb 06 2023 at 16:28, Song Liu 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. > > > > 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> > > With the comment update folded in: > > Reviewed-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Thanks! I've merged this onto modules-next for winder testing. It is too late for v6.2 as we're on rc7 but this just means we'll get testing on linux-next for a good while for v6.3. If other folks do complete review please send your Reviewed-by annotation so I can ammend the commit log as we go. Luis
