2 files changed, 106 insertions, 0 deletions
diff --git a/arch/riscv/errata/thead/Makefile b/arch/riscv/errata/thead/Makefile
new file mode 100644
index 000000000..137e700d9
--- /dev/null
+++ b/arch/riscv/errata/thead/Makefile
@@ -0,0 +1,11 @@
+ifdef CONFIG_RISCV_ALTERNATIVE_EARLY
+CFLAGS_errata.o := -mcmodel=medany
+ifdef CONFIG_FTRACE
+CFLAGS_REMOVE_errata.o = $(CC_FLAGS_FTRACE)
+endif
+ifdef CONFIG_KASAN
+KASAN_SANITIZE_errata.o := n
+endif
+endif
+
+obj-y += errata.o
diff --git a/arch/riscv/errata/thead/errata.c b/arch/riscv/errata/thead/errata.c
new file mode 100644
index 000000000..32a34ed73
--- /dev/null
+++ b/arch/riscv/errata/thead/errata.c
@@ -0,0 +1,95 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2021 Heiko Stuebner <heiko@sntech.de>
+ */
+
+#include <linux/bug.h>
+#include <linux/kernel.h>
+#include <linux/memory.h>
+#include <linux/module.h>
+#include <linux/string.h>
+#include <linux/uaccess.h>
+#include <asm/alternative.h>
+#include <asm/cacheflush.h>
+#include <asm/errata_list.h>
+#include <asm/patch.h>
+#include <asm/vendorid_list.h>
+
+static bool errata_probe_pbmt(unsigned int stage,
+			      unsigned long arch_id, unsigned long impid)
+{
+	if (!IS_ENABLED(CONFIG_ERRATA_THEAD_PBMT))
+		return false;
+
+	if (arch_id != 0 || impid != 0)
+		return false;
+
+	if (stage == RISCV_ALTERNATIVES_EARLY_BOOT ||
+	    stage == RISCV_ALTERNATIVES_MODULE)
+		return true;
+
+	return false;
+}
+
+static bool errata_probe_cmo(unsigned int stage,
+			     unsigned long arch_id, unsigned long impid)
+{
+	if (!IS_ENABLED(CONFIG_ERRATA_THEAD_CMO))
+		return false;
+
+	if (arch_id != 0 || impid != 0)
+		return false;
+
+	if (stage == RISCV_ALTERNATIVES_EARLY_BOOT)
+		return false;
+
+	riscv_cbom_block_size = L1_CACHE_BYTES;
+	riscv_noncoherent_supported();
+	return true;
+}
+
+static u32 thead_errata_probe(unsigned int stage,
+			      unsigned long archid, unsigned long impid)
+{
+	u32 cpu_req_errata = 0;
+
+	if (errata_probe_pbmt(stage, archid, impid))
+		cpu_req_errata |= BIT(ERRATA_THEAD_PBMT);
+
+	if (errata_probe_cmo(stage, archid, impid))
+		cpu_req_errata |= BIT(ERRATA_THEAD_CMO);
+
+	return cpu_req_errata;
+}
+
+void __init_or_module thead_errata_patch_func(struct alt_entry *begin, struct alt_entry *end,
+					      unsigned long archid, unsigned long impid,
+					      unsigned int stage)
+{
+	struct alt_entry *alt;
+	u32 cpu_req_errata = thead_errata_probe(stage, archid, impid);
+	u32 tmp;
+
+	for (alt = begin; alt < end; alt++) {
+		if (alt->vendor_id != THEAD_VENDOR_ID)
+			continue;
+		if (alt->errata_id >= ERRATA_THEAD_NUMBER)
+			continue;
+
+		tmp = (1U << alt->errata_id);
+		if (cpu_req_errata & tmp) {
+			/* On vm-alternatives, the mmu isn't running yet */
+			if (stage == RISCV_ALTERNATIVES_EARLY_BOOT) {
+				memcpy((void *)__pa_symbol(alt->old_ptr),
+				       (void *)__pa_symbol(alt->alt_ptr), alt->alt_len);
+			} else {
+				mutex_lock(&text_mutex);
+				patch_text_nosync(alt->old_ptr, alt->alt_ptr, alt->alt_len);
+				mutex_unlock(&text_mutex);
+			}
+		}
+	}
+
+	if (stage == RISCV_ALTERNATIVES_EARLY_BOOT)
+		local_flush_icache_all();
+}