diff --git a/sys/compat/linuxkpi/common/include/linux/module.h b/sys/compat/linuxkpi/common/include/linux/module.h index 9d98ef7cf3db..079dacf8df6c 100644 --- a/sys/compat/linuxkpi/common/include/linux/module.h +++ b/sys/compat/linuxkpi/common/include/linux/module.h @@ -32,6 +32,8 @@ #include #include #include +#include +#include #include #include @@ -51,7 +53,26 @@ #define MODULE_SUPPORTED_DEVICE(name) #define MODULE_IMPORT_NS(_name) +/* + * THIS_MODULE is used to differentiate modules on Linux. We currently + * completely stub out any Linux struct module usage, but THIS_MODULE is still + * used to populate the "owner" fields of various drivers. Even though we + * don't actually dereference these "owner" fields they are still used by + * drivers to check if devices/dmabufs/etc come from different modules. For + * example, during DRM GEM import some drivers check if the dmabuf's owner + * matches the dev's owner. If they match because they are both NULL drivers + * may incorrectly think two resources come from the same module. + * + * To handle this we specify an undefined symbol __this_linker_file, which + * will get special treatment from the linker when resolving. This will + * populate the usages of __this_linker_file with the linker_file_t of the + * module. + */ +#ifdef KLD_MODULE +#define THIS_MODULE ((struct module *)&__this_linker_file) +#else #define THIS_MODULE ((struct module *)0) +#endif #define __MODULE_STRING(x) __stringify(x) diff --git a/sys/kern/kern_linker.c b/sys/kern/kern_linker.c index 08b85867d781..3f34bb12aeaa 100644 --- a/sys/kern/kern_linker.c +++ b/sys/kern/kern_linker.c @@ -906,6 +906,20 @@ linker_file_lookup_symbol_internal(linker_file_t file, const char *name, KLD_DPF(SYM, ("linker_file_lookup_symbol: file=%p, name=%s, deps=%d\n", file, name, deps)); + /* + * Treat the __this_linker_file as a special symbol. This is a + * global that linuxkpi uses to populate the THIS_MODULE + * value. In this case we can simply return the linker_file_t. + * + * Modules compiled statically into the kernel are assigned NULL. + */ + if (strcmp(name, "__this_linker_file") == 0) { + address = (file == linker_kernel_file) ? NULL : (caddr_t)file; + KLD_DPF(SYM, ("linker_file_lookup_symbol: resolving special " + "symbol __this_linker_file to %p\n", address)); + return (address); + } + if (LINKER_LOOKUP_SYMBOL(file, name, &sym) == 0) { LINKER_SYMBOL_VALUES(file, sym, &symval); if (symval.value == 0) diff --git a/sys/sys/linker.h b/sys/sys/linker.h index 52fbeb5584ff..06e950f7affe 100644 --- a/sys/sys/linker.h +++ b/sys/sys/linker.h @@ -130,6 +130,12 @@ typedef int linker_predicate_t(linker_file_t, void *); */ extern linker_file_t linker_kernel_file; +/* + * Special symbol which will be replaced by a reference to the linker_file_t + * of the module it is used in. + */ +extern linker_file_t __this_linker_file; + /* * Obtain a reference to a module, loading it if required. */