85 lines
2.5 KiB
C
85 lines
2.5 KiB
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
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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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#include <asm/pgtable.h>
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#include <asm/cacheflush.h>
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#ifdef CONFIG_SMP
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#include <asm/sbi.h>
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void flush_icache_all(void)
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{
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sbi_remote_fence_i(NULL);
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}
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/*
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* Performs an icache flush for the given MM context. RISC-V has no direct
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* mechanism for instruction cache shoot downs, so instead we send an IPI that
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* informs the remote harts they need to flush their local instruction caches.
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* To avoid pathologically slow behavior in a common case (a bunch of
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* single-hart processes on a many-hart machine, ie 'make -j') we avoid the
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* IPIs for harts that are not currently executing a MM context and instead
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* schedule a deferred local instruction cache flush to be performed before
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* execution resumes on each hart.
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*/
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void flush_icache_mm(struct mm_struct *mm, bool local)
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{
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unsigned int cpu;
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cpumask_t others, hmask, *mask;
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preempt_disable();
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/* Mark every hart's icache as needing a flush for this MM. */
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mask = &mm->context.icache_stale_mask;
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cpumask_setall(mask);
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/* Flush this hart's I$ now, and mark it as flushed. */
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cpu = smp_processor_id();
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cpumask_clear_cpu(cpu, mask);
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local_flush_icache_all();
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/*
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* Flush the I$ of other harts concurrently executing, and mark them as
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* flushed.
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*/
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cpumask_andnot(&others, mm_cpumask(mm), cpumask_of(cpu));
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local |= cpumask_empty(&others);
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if (mm != current->active_mm || !local) {
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cpumask_clear(&hmask);
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riscv_cpuid_to_hartid_mask(&others, &hmask);
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sbi_remote_fence_i(hmask.bits);
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} else {
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/*
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* It's assumed that at least one strongly ordered operation is
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* performed on this hart between setting a hart's cpumask bit
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* and scheduling this MM context on that hart. Sending an SBI
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* remote message will do this, but in the case where no
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* messages are sent we still need to order this hart's writes
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* with flush_icache_deferred().
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*/
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smp_mb();
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}
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preempt_enable();
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}
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#endif /* CONFIG_SMP */
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void flush_icache_pte(pte_t pte)
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{
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struct page *page = pte_page(pte);
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if (!test_and_set_bit(PG_dcache_clean, &page->flags))
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flush_icache_all();
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}
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