xref: /openbmc/linux/arch/riscv/include/uapi/asm/unistd.h (revision b830f94f)
1 /* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
2 /*
3  * Copyright (C) 2018 David Abdurachmanov <david.abdurachmanov@gmail.com>
4  *
5  * This program is free software; you can redistribute it and/or modify
6  * it under the terms of the GNU General Public License version 2 as
7  * published by the Free Software Foundation.
8  *
9  * This program is distributed in the hope that it will be useful,
10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12  * GNU General Public License for more details.
13  *
14  * You should have received a copy of the GNU General Public License
15  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
16  */
17 
18 #ifdef __LP64__
19 #define __ARCH_WANT_NEW_STAT
20 #define __ARCH_WANT_SET_GET_RLIMIT
21 #endif /* __LP64__ */
22 
23 #include <asm-generic/unistd.h>
24 
25 /*
26  * Allows the instruction cache to be flushed from userspace.  Despite RISC-V
27  * having a direct 'fence.i' instruction available to userspace (which we
28  * can't trap!), that's not actually viable when running on Linux because the
29  * kernel might schedule a process on another hart.  There is no way for
30  * userspace to handle this without invoking the kernel (as it doesn't know the
31  * thread->hart mappings), so we've defined a RISC-V specific system call to
32  * flush the instruction cache.
33  *
34  * __NR_riscv_flush_icache is defined to flush the instruction cache over an
35  * address range, with the flush applying to either all threads or just the
36  * caller.  We don't currently do anything with the address range, that's just
37  * in there for forwards compatibility.
38  */
39 #ifndef __NR_riscv_flush_icache
40 #define __NR_riscv_flush_icache (__NR_arch_specific_syscall + 15)
41 #endif
42 __SYSCALL(__NR_riscv_flush_icache, sys_riscv_flush_icache)
43