// 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); } void arch_jump_label_transform_static(struct jump_entry *entry, enum jump_label_type type) { /* * We use the same instructions in the arch_static_branch and * arch_static_branch_jump inline functions, so there's no * need to patch them up here. * The core will call arch_jump_label_transform when those * instructions need to be replaced. */ }