921ebd8f2c
Despite RISC-V having a direct 'fence.i' instruction available to userspace (which we can't trap!), that's not actually viable when running on Linux because the kernel might schedule a process on another hart. There is no way for userspace to handle this without invoking the kernel (as it doesn't know the thread->hart mappings), so we've defined a RISC-V specific system call to flush the instruction cache. This patch adds both a system call and a VDSO entry. If possible, we'd like to avoid having the system call be considered part of the user-facing ABI and instead restrict that to the VDSO entry -- both just in general to avoid having additional user-visible ABI to maintain, and because we'd prefer that users just call the VDSO entry because there might be a better way to do this in the future (ie, one that doesn't require entering the kernel). Signed-off-by: Andrew Waterman <andrew@sifive.com> Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
29 lines
948 B
C
29 lines
948 B
C
/*
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* Copyright (C) 2017 SiFive
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#ifndef _ASM_RISCV_VDSO_SYSCALLS_H
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#define _ASM_RISCV_VDSO_SYSCALLS_H
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#ifdef CONFIG_SMP
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/* These syscalls are only used by the vDSO and are not in the uapi. */
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#define __NR_riscv_flush_icache (__NR_arch_specific_syscall + 15)
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__SYSCALL(__NR_riscv_flush_icache, sys_riscv_flush_icache)
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#endif
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#endif /* _ASM_RISCV_VDSO_H */
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