| All headers under include/export/ are export headers that are intended for | |
| inclusion in third-party code which needs to interact with TF-A data structures | |
| or interfaces. They must follow these special rules: | |
| - Header guards should start with ARM_TRUSTED_FIRMWARE_ to reduce clash risk. | |
| - All definitions should be sufficiently namespaced (e.g. with BL_ or TF_) to | |
| make name clashes with third-party code unlikely. | |
| - They must not #include any headers except other export headers, and those | |
| includes must use relative paths with "../double_quotes.h" notation. | |
| - They must not rely on any type definitions other that <stdint.h> types defined | |
| in the ISO C standard (i.e. uint64_t is fine, but not u_register_t). They | |
| should still not #include <stdint.h>. Instead, wrapper headers including | |
| export headers need to ensure that they #include <stdint.h> earlier in their | |
| include order. | |
| - They must not rely on any macro definitions other than those which are | |
| pre-defined by all common compilers (e.g. __ASSEMBLER__ or __aarch64__). | |
| - They must only contain macro, type and structure definitions, no prototypes. | |
| - They should avoid using integer types with architecture-dependent widths | |
| (e.g. long, uintptr_t, pointer types) where possible. (Some existing export | |
| headers are violating this for now.) | |
| - Their names should always end in "_exp.h". | |
| - Normal TF-A code should never include export headers directly. Instead, it | |
| should include a wrapper header that ensures the export header is included in | |
| the right manner. (The wrapper header for include/export/x/y/z_exp.h should | |
| normally be placed at include/x/y/z.h.) |