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-rw-r--r--arch/riscv/kernel/jump_label.c41
1 files changed, 41 insertions, 0 deletions
diff --git a/arch/riscv/kernel/jump_label.c b/arch/riscv/kernel/jump_label.c
new file mode 100644
index 000000000..e6694759d
--- /dev/null
+++ b/arch/riscv/kernel/jump_label.c
@@ -0,0 +1,41 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2020 Emil Renner Berthing
+ *
+ * Based on arch/arm64/kernel/jump_label.c
+ */
+#include <linux/jump_label.h>
+#include <linux/kernel.h>
+#include <linux/memory.h>
+#include <linux/mutex.h>
+#include <asm/bug.h>
+#include <asm/patch.h>
+
+#define RISCV_INSN_NOP 0x00000013U
+#define RISCV_INSN_JAL 0x0000006fU
+
+void arch_jump_label_transform(struct jump_entry *entry,
+ enum jump_label_type type)
+{
+ void *addr = (void *)jump_entry_code(entry);
+ u32 insn;
+
+ if (type == JUMP_LABEL_JMP) {
+ long offset = jump_entry_target(entry) - jump_entry_code(entry);
+
+ if (WARN_ON(offset & 1 || offset < -524288 || offset >= 524288))
+ return;
+
+ insn = RISCV_INSN_JAL |
+ (((u32)offset & GENMASK(19, 12)) << (12 - 12)) |
+ (((u32)offset & GENMASK(11, 11)) << (20 - 11)) |
+ (((u32)offset & GENMASK(10, 1)) << (21 - 1)) |
+ (((u32)offset & GENMASK(20, 20)) << (31 - 20));
+ } else {
+ insn = RISCV_INSN_NOP;
+ }
+
+ mutex_lock(&text_mutex);
+ patch_text_nosync(addr, &insn, sizeof(insn));
+ mutex_unlock(&text_mutex);
+}