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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>
62 lines
1.7 KiB
C
62 lines
1.7 KiB
C
/*
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* Copyright (C) 2015 Regents of the University of California
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation, version 2.
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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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#ifndef _ASM_RISCV_CACHEFLUSH_H
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#define _ASM_RISCV_CACHEFLUSH_H
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#include <asm-generic/cacheflush.h>
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#undef flush_icache_range
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#undef flush_icache_user_range
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#undef flush_dcache_page
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static inline void local_flush_icache_all(void)
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{
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asm volatile ("fence.i" ::: "memory");
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}
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#define PG_dcache_clean PG_arch_1
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static inline void flush_dcache_page(struct page *page)
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{
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if (test_bit(PG_dcache_clean, &page->flags))
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clear_bit(PG_dcache_clean, &page->flags);
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}
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/*
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* RISC-V doesn't have an instruction to flush parts of the instruction cache,
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* so instead we just flush the whole thing.
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*/
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#define flush_icache_range(start, end) flush_icache_all()
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#define flush_icache_user_range(vma, pg, addr, len) flush_icache_all()
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#ifndef CONFIG_SMP
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#define flush_icache_all() local_flush_icache_all()
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#define flush_icache_mm(mm, local) flush_icache_all()
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#else /* CONFIG_SMP */
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#define flush_icache_all() sbi_remote_fence_i(0)
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void flush_icache_mm(struct mm_struct *mm, bool local);
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#endif /* CONFIG_SMP */
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/*
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* Bits in sys_riscv_flush_icache()'s flags argument.
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*/
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#define SYS_RISCV_FLUSH_ICACHE_LOCAL 1UL
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#define SYS_RISCV_FLUSH_ICACHE_ALL (SYS_RISCV_FLUSH_ICACHE_LOCAL)
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#endif /* _ASM_RISCV_CACHEFLUSH_H */
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