| // Copyright 2016 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. |
| |
| // For each function in the vDSO ABI, define a symbol in the linker script |
| // pointing to its address. The vDSO is loaded immediately after the |
| // userboot DSO image's last page, which is found by aligning the magic |
| // symbol _end (generated by the linker) up to the next page boundary. So |
| // these symbols tell the linker where each vDSO function will be found at |
| // runtime. The userboot code uses normal calls to these, declared as have |
| // hidden visibility so they won't generate PLT entries. This results in |
| // the userboot binary having simple PC-relative calls to addresses outside |
| // its own image, to where the vDSO will be found at runtime. |
| #define FUNCTION(name, address, size) \ |
| PROVIDE_HIDDEN(name = ALIGN(_end, CONSTANT(MAXPAGESIZE)) + address); |
| |
| #define WEAK_FUNCTION(name, address, size) FUNCTION(name, address, size) |
