65 строки
1.9 KiB
C
65 строки
1.9 KiB
C
// SPDX-License-Identifier: GPL-2.0
|
|
/*
|
|
* Copyright (C) 2012 Regents of the University of California
|
|
* Copyright (C) 2017 SiFive
|
|
*/
|
|
|
|
#include <linux/mm.h>
|
|
#include <asm/tlbflush.h>
|
|
#include <asm/cacheflush.h>
|
|
|
|
/*
|
|
* When necessary, performs a deferred icache flush for the given MM context,
|
|
* on the local CPU. 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. This
|
|
* actually performs that local instruction cache flush, which implicitly only
|
|
* refers to the current hart.
|
|
*/
|
|
static inline void flush_icache_deferred(struct mm_struct *mm)
|
|
{
|
|
#ifdef CONFIG_SMP
|
|
unsigned int cpu = smp_processor_id();
|
|
cpumask_t *mask = &mm->context.icache_stale_mask;
|
|
|
|
if (cpumask_test_cpu(cpu, mask)) {
|
|
cpumask_clear_cpu(cpu, mask);
|
|
/*
|
|
* Ensure the remote hart's writes are visible to this hart.
|
|
* This pairs with a barrier in flush_icache_mm.
|
|
*/
|
|
smp_mb();
|
|
local_flush_icache_all();
|
|
}
|
|
|
|
#endif
|
|
}
|
|
|
|
void switch_mm(struct mm_struct *prev, struct mm_struct *next,
|
|
struct task_struct *task)
|
|
{
|
|
unsigned int cpu;
|
|
|
|
if (unlikely(prev == next))
|
|
return;
|
|
|
|
/*
|
|
* Mark the current MM context as inactive, and the next as
|
|
* active. This is at least used by the icache flushing
|
|
* routines in order to determine who should be flushed.
|
|
*/
|
|
cpu = smp_processor_id();
|
|
|
|
cpumask_clear_cpu(cpu, mm_cpumask(prev));
|
|
cpumask_set_cpu(cpu, mm_cpumask(next));
|
|
|
|
csr_write(CSR_SATP, virt_to_pfn(next->pgd) | SATP_MODE);
|
|
local_flush_tlb_all();
|
|
|
|
flush_icache_deferred(next);
|
|
}
|