| // Copyright 2025 The Fuchsia Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #ifndef LIB_C_STARTUP_STARTUP_RANDOM_H_ |
| #define LIB_C_STARTUP_STARTUP_RANDOM_H_ |
| |
| #include "../asm-linkage.h" |
| #include "src/__support/macros/config.h" |
| |
| namespace LIBC_NAMESPACE_DECL { |
| |
| // Use this as an attribute to define an uninitialized variable of trivial |
| // type. It will be filled with random bits by InitStartupRandom(). |
| #define LIBC_STARTUP_RANDOM_VAR [[gnu::section(LIBC_ASM_LINKAGE_STRING(StartupRandom))]] |
| |
| // This fills all LIBC_STARTUP_RANDOM_VAR objects with random bits. This is |
| // called very early, before the compiler ABI is set up. In fact, it's also |
| // what initializes the main thread's ZX_TLS_STACK_GUARD_OFFSET slot with |
| // random bits. Therefore it's built with an hermetic partial link, and so |
| // needs LIBC_ASM_LINKAGE. |
| void InitStartupRandom() LIBC_ASM_LINKAGE_DECLARE(InitStartupRandom); |
| |
| } // namespace LIBC_NAMESPACE_DECL |
| |
| #endif // LIB_C_STARTUP_STARTUP_RANDOM_H_ |
