| /* Copyright (C) 2023 Free Software Foundation, Inc. |
| |
| This file is free software; you can redistribute it and/or modify it |
| under the terms of the GNU General Public License as published by the |
| Free Software Foundation; either version 3, or (at your option) any |
| later version. |
| |
| This file is distributed in the hope that it will be useful, but |
| WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| General Public License for more details. |
| |
| Under Section 7 of GPL version 3, you are granted additional |
| permissions described in the GCC Runtime Library Exception, version |
| 3.1, as published by the Free Software Foundation. |
| |
| You should have received a copy of the GNU General Public License and |
| a copy of the GCC Runtime Library Exception along with this program; |
| see the files COPYING3 and COPYING.RUNTIME respectively. If not, see |
| <http://www.gnu.org/licenses/>. */ |
| |
| //#include "mips16.S" |
| |
| #ifdef L_speculation_barrier |
| |
| /* MIPS16e1 has no sync/jr.hb instructions, and MIPS16e2 lacks of jr.hb. |
| So, we use normal MIPS code here, just like what we do for __sync_*. */ |
| .set nomips16 |
| |
| .set noreorder |
| .globl __speculation_barrier |
| .ent __speculation_barrier |
| |
| __speculation_barrier: |
| .set push |
| #if __mips >= 2 |
| sync /* complementation barrier for memory. */ |
| #elif defined (__linux) |
| /* MIPS1 has no sync, while Linux can trap&emu sync. */ |
| /* FIXME: Will somebody use linux/gcc for MIPS1/baremetal? */ |
| .word 0x0000000f |
| #endif |
| |
| |
| #if __mips_isa_rev >= 1 |
| /* Binutils claims that JR in R1 can do same as jr.hb. |
| R6 changes the encoding of jr.hb. */ |
| jr.hb $ra /* Jump with instruction hazard barrier. */ |
| #else |
| /* ssnop is actually available since R5500, |
| and it will be decoded as nop on earlier processors. |
| gas can only recognize it with -march=mips1 since 2.21. |
| MIPS1 to MIPSr1: R10000 have 7 stage pipeline, |
| so 8 ssnop is sufficient to block all speculation on all CPUs. */ |
| .rept 8 |
| .word 0x00000040 /* The encoding of ssnop. */ |
| .endr |
| /* jr.hb will be decoded as jr on earlier processors. */ |
| .word 0x03e00408 /* The encoding of jr.hb $ra. */ |
| #endif |
| .set pop |
| .end __speculation_barrier |
| |
| .set reorder |
| #endif |
