1 files changed, 141 insertions, 0 deletions
diff --git a/arch/riscv/mm/cacheflush.c b/arch/riscv/mm/cacheflush.c
new file mode 100644
index 0000000000..f1387272a5
--- /dev/null
+++ b/arch/riscv/mm/cacheflush.c
@@ -0,0 +1,141 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2017 SiFive
+ */
+
+#include <linux/of.h>
+#include <asm/cacheflush.h>
+
+#ifdef CONFIG_SMP
+
+#include <asm/sbi.h>
+
+static void ipi_remote_fence_i(void *info)
+{
+	return local_flush_icache_all();
+}
+
+void flush_icache_all(void)
+{
+	local_flush_icache_all();
+
+	if (IS_ENABLED(CONFIG_RISCV_SBI) && !riscv_use_ipi_for_rfence())
+		sbi_remote_fence_i(NULL);
+	else
+		on_each_cpu(ipi_remote_fence_i, NULL, 1);
+}
+EXPORT_SYMBOL(flush_icache_all);
+
+/*
+ * 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, *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) {
+		/*
+		 * 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();
+	} else if (IS_ENABLED(CONFIG_RISCV_SBI) &&
+		   !riscv_use_ipi_for_rfence()) {
+		sbi_remote_fence_i(&others);
+	} else {
+		on_each_cpu_mask(&others, ipi_remote_fence_i, NULL, 1);
+	}
+
+	preempt_enable();
+}
+
+#endif /* CONFIG_SMP */
+
+#ifdef CONFIG_MMU
+void flush_icache_pte(pte_t pte)
+{
+	struct folio *folio = page_folio(pte_page(pte));
+
+	if (!test_bit(PG_dcache_clean, &folio->flags)) {
+		flush_icache_all();
+		set_bit(PG_dcache_clean, &folio->flags);
+	}
+}
+#endif /* CONFIG_MMU */
+
+unsigned int riscv_cbom_block_size;
+EXPORT_SYMBOL_GPL(riscv_cbom_block_size);
+
+unsigned int riscv_cboz_block_size;
+EXPORT_SYMBOL_GPL(riscv_cboz_block_size);
+
+static void __init cbo_get_block_size(struct device_node *node,
+				      const char *name, u32 *block_size,
+				      unsigned long *first_hartid)
+{
+	unsigned long hartid;
+	u32 val;
+
+	if (riscv_of_processor_hartid(node, &hartid))
+		return;
+
+	if (of_property_read_u32(node, name, &val))
+		return;
+
+	if (!*block_size) {
+		*block_size = val;
+		*first_hartid = hartid;
+	} else if (*block_size != val) {
+		pr_warn("%s mismatched between harts %lu and %lu\n",
+			name, *first_hartid, hartid);
+	}
+}
+
+void __init riscv_init_cbo_blocksizes(void)
+{
+	unsigned long cbom_hartid, cboz_hartid;
+	u32 cbom_block_size = 0, cboz_block_size = 0;
+	struct device_node *node;
+
+	for_each_of_cpu_node(node) {
+		/* set block-size for cbom and/or cboz extension if available */
+		cbo_get_block_size(node, "riscv,cbom-block-size",
+				   &cbom_block_size, &cbom_hartid);
+		cbo_get_block_size(node, "riscv,cboz-block-size",
+				   &cboz_block_size, &cboz_hartid);
+	}
+
+	if (cbom_block_size)
+		riscv_cbom_block_size = cbom_block_size;
+
+	if (cboz_block_size)
+		riscv_cboz_block_size = cboz_block_size;
+}