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/*
* Copyright (C) 2017 SiFive
*
* This program 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, version 2.
*
* This program 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.
*/
#include <asm/pgtable.h>
#include <asm/cacheflush.h>
#ifdef CONFIG_SMP
#include <asm/sbi.h>
void flush_icache_all(void)
{
sbi_remote_fence_i(NULL);
}
/*
* Performs an icache flush for the given MM context. RISC-V has no direct
* mechanism for instruction cache shoot downs, so instead we send an IPI that
* informs the remote harts they need to flush their local instruction caches.
* To avoid pathologically slow behavior in a common case (a bunch of
* single-hart processes on a many-hart machine, ie 'make -j') we avoid the
* IPIs for harts that are not currently executing a MM context and instead
* schedule a deferred local instruction cache flush to be performed before
* execution resumes on each hart.
*/
void flush_icache_mm(struct mm_struct *mm, bool local)
{
unsigned int cpu;
cpumask_t others, hmask, *mask;
preempt_disable();
/* Mark every hart's icache as needing a flush for this MM. */
mask = &mm->context.icache_stale_mask;
cpumask_setall(mask);
/* Flush this hart's I$ now, and mark it as flushed. */
cpu = smp_processor_id();
cpumask_clear_cpu(cpu, mask);
local_flush_icache_all();
/*
* Flush the I$ of other harts concurrently executing, and mark them as
* flushed.
*/
cpumask_andnot(&others, mm_cpumask(mm), cpumask_of(cpu));
local |= cpumask_empty(&others);
if (mm != current->active_mm || !local) {
cpumask_clear(&hmask);
riscv_cpuid_to_hartid_mask(&others, &hmask);
sbi_remote_fence_i(hmask.bits);
} else {
/*
* It's assumed that at least one strongly ordered operation is
* performed on this hart between setting a hart's cpumask bit
* and scheduling this MM context on that hart. Sending an SBI
* remote message will do this, but in the case where no
* messages are sent we still need to order this hart's writes
* with flush_icache_deferred().
*/
smp_mb();
}
preempt_enable();
}
#endif /* CONFIG_SMP */
void flush_icache_pte(pte_t pte)
{
struct page *page = pte_page(pte);
if (!test_and_set_bit(PG_dcache_clean, &page->flags))
flush_icache_all();
}
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