Linux kernel mirror (for testing)
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linux
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) 2017 SiFive
4 */
5
6#include <linux/of.h>
7#include <asm/cacheflush.h>
8
9#ifdef CONFIG_SMP
10
11#include <asm/sbi.h>
12
13static void ipi_remote_fence_i(void *info)
14{
15 return local_flush_icache_all();
16}
17
18void flush_icache_all(void)
19{
20 local_flush_icache_all();
21
22 if (IS_ENABLED(CONFIG_RISCV_SBI) && !riscv_use_ipi_for_rfence())
23 sbi_remote_fence_i(NULL);
24 else
25 on_each_cpu(ipi_remote_fence_i, NULL, 1);
26}
27EXPORT_SYMBOL(flush_icache_all);
28
29/*
30 * Performs an icache flush for the given MM context. RISC-V has no direct
31 * mechanism for instruction cache shoot downs, so instead we send an IPI that
32 * informs the remote harts they need to flush their local instruction caches.
33 * To avoid pathologically slow behavior in a common case (a bunch of
34 * single-hart processes on a many-hart machine, ie 'make -j') we avoid the
35 * IPIs for harts that are not currently executing a MM context and instead
36 * schedule a deferred local instruction cache flush to be performed before
37 * execution resumes on each hart.
38 */
39void flush_icache_mm(struct mm_struct *mm, bool local)
40{
41 unsigned int cpu;
42 cpumask_t others, *mask;
43
44 preempt_disable();
45
46 /* Mark every hart's icache as needing a flush for this MM. */
47 mask = &mm->context.icache_stale_mask;
48 cpumask_setall(mask);
49 /* Flush this hart's I$ now, and mark it as flushed. */
50 cpu = smp_processor_id();
51 cpumask_clear_cpu(cpu, mask);
52 local_flush_icache_all();
53
54 /*
55 * Flush the I$ of other harts concurrently executing, and mark them as
56 * flushed.
57 */
58 cpumask_andnot(&others, mm_cpumask(mm), cpumask_of(cpu));
59 local |= cpumask_empty(&others);
60 if (mm == current->active_mm && local) {
61 /*
62 * It's assumed that at least one strongly ordered operation is
63 * performed on this hart between setting a hart's cpumask bit
64 * and scheduling this MM context on that hart. Sending an SBI
65 * remote message will do this, but in the case where no
66 * messages are sent we still need to order this hart's writes
67 * with flush_icache_deferred().
68 */
69 smp_mb();
70 } else if (IS_ENABLED(CONFIG_RISCV_SBI) &&
71 !riscv_use_ipi_for_rfence()) {
72 sbi_remote_fence_i(&others);
73 } else {
74 on_each_cpu_mask(&others, ipi_remote_fence_i, NULL, 1);
75 }
76
77 preempt_enable();
78}
79
80#endif /* CONFIG_SMP */
81
82#ifdef CONFIG_MMU
83void flush_icache_pte(pte_t pte)
84{
85 struct page *page = pte_page(pte);
86
87 /*
88 * HugeTLB pages are always fully mapped, so only setting head page's
89 * PG_dcache_clean flag is enough.
90 */
91 if (PageHuge(page))
92 page = compound_head(page);
93
94 if (!test_bit(PG_dcache_clean, &page->flags)) {
95 flush_icache_all();
96 set_bit(PG_dcache_clean, &page->flags);
97 }
98}
99#endif /* CONFIG_MMU */
100
101unsigned int riscv_cbom_block_size;
102EXPORT_SYMBOL_GPL(riscv_cbom_block_size);
103
104unsigned int riscv_cboz_block_size;
105EXPORT_SYMBOL_GPL(riscv_cboz_block_size);
106
107static void cbo_get_block_size(struct device_node *node,
108 const char *name, u32 *block_size,
109 unsigned long *first_hartid)
110{
111 unsigned long hartid;
112 u32 val;
113
114 if (riscv_of_processor_hartid(node, &hartid))
115 return;
116
117 if (of_property_read_u32(node, name, &val))
118 return;
119
120 if (!*block_size) {
121 *block_size = val;
122 *first_hartid = hartid;
123 } else if (*block_size != val) {
124 pr_warn("%s mismatched between harts %lu and %lu\n",
125 name, *first_hartid, hartid);
126 }
127}
128
129void riscv_init_cbo_blocksizes(void)
130{
131 unsigned long cbom_hartid, cboz_hartid;
132 u32 cbom_block_size = 0, cboz_block_size = 0;
133 struct device_node *node;
134
135 for_each_of_cpu_node(node) {
136 /* set block-size for cbom and/or cboz extension if available */
137 cbo_get_block_size(node, "riscv,cbom-block-size",
138 &cbom_block_size, &cbom_hartid);
139 cbo_get_block_size(node, "riscv,cboz-block-size",
140 &cboz_block_size, &cboz_hartid);
141 }
142
143 if (cbom_block_size)
144 riscv_cbom_block_size = cbom_block_size;
145
146 if (cboz_block_size)
147 riscv_cboz_block_size = cboz_block_size;
148}