1// SPDX-License-Identifier: GPL-2.0-only
 2/*
 3 * Copyright (C) 2017 SiFive
 4 */
 5
 6#include <asm/cacheflush.h>
 7
 8#ifdef CONFIG_SMP
 9
10#include <asm/sbi.h>
11
12static void ipi_remote_fence_i(void *info)
13{
14	return local_flush_icache_all();
15}
16
17void flush_icache_all(void)
18{
19	if (IS_ENABLED(CONFIG_RISCV_SBI))
20		sbi_remote_fence_i(NULL);
21	else
22		on_each_cpu(ipi_remote_fence_i, NULL, 1);
23}
24EXPORT_SYMBOL(flush_icache_all);
25
26/*
27 * Performs an icache flush for the given MM context.  RISC-V has no direct
28 * mechanism for instruction cache shoot downs, so instead we send an IPI that
29 * informs the remote harts they need to flush their local instruction caches.
30 * To avoid pathologically slow behavior in a common case (a bunch of
31 * single-hart processes on a many-hart machine, ie 'make -j') we avoid the
32 * IPIs for harts that are not currently executing a MM context and instead
33 * schedule a deferred local instruction cache flush to be performed before
34 * execution resumes on each hart.
35 */
36void flush_icache_mm(struct mm_struct *mm, bool local)
37{
38	unsigned int cpu;
39	cpumask_t others, *mask;
40
41	preempt_disable();
42
43	/* Mark every hart's icache as needing a flush for this MM. */
44	mask = &mm->context.icache_stale_mask;
45	cpumask_setall(mask);
46	/* Flush this hart's I$ now, and mark it as flushed. */
47	cpu = smp_processor_id();
48	cpumask_clear_cpu(cpu, mask);
49	local_flush_icache_all();
50
51	/*
52	 * Flush the I$ of other harts concurrently executing, and mark them as
53	 * flushed.
54	 */
55	cpumask_andnot(&others, mm_cpumask(mm), cpumask_of(cpu));
56	local |= cpumask_empty(&others);
57	if (mm == current->active_mm && local) {
58		/*
59		 * It's assumed that at least one strongly ordered operation is
60		 * performed on this hart between setting a hart's cpumask bit
61		 * and scheduling this MM context on that hart.  Sending an SBI
62		 * remote message will do this, but in the case where no
63		 * messages are sent we still need to order this hart's writes
64		 * with flush_icache_deferred().
65		 */
66		smp_mb();
67	} else if (IS_ENABLED(CONFIG_RISCV_SBI)) {
68		cpumask_t hartid_mask;
69
70		riscv_cpuid_to_hartid_mask(&others, &hartid_mask);
71		sbi_remote_fence_i(cpumask_bits(&hartid_mask));
72	} else {
73		on_each_cpu_mask(&others, ipi_remote_fence_i, NULL, 1);
74	}
75
76	preempt_enable();
77}
78
79#endif /* CONFIG_SMP */
80
81#ifdef CONFIG_MMU
82void flush_icache_pte(pte_t pte)
83{
84	struct page *page = pte_page(pte);
85
86	if (!test_and_set_bit(PG_dcache_clean, &page->flags))
87		flush_icache_all();
88}
89#endif /* CONFIG_MMU */