1 /* SPDX-License-Identifier: GPL-2.0-only */ 2 /* 3 * Copyright (C) 2020 Emil Renner Berthing 4 * 5 * Based on arch/arm64/include/asm/jump_label.h 6 */ 7 #ifndef __ASM_JUMP_LABEL_H 8 #define __ASM_JUMP_LABEL_H 9 10 #ifndef __ASSEMBLY__ 11 12 #include <linux/types.h> 13 #include <asm/asm.h> 14 15 #define HAVE_JUMP_LABEL_BATCH 16 17 #define JUMP_LABEL_NOP_SIZE 4 18 19 #define JUMP_TABLE_ENTRY(key, label) \ 20 ".pushsection __jump_table, \"aw\" \n\t" \ 21 ".align " RISCV_LGPTR " \n\t" \ 22 ".long 1b - ., " label " - . \n\t" \ 23 "" RISCV_PTR " " key " - . \n\t" \ 24 ".popsection \n\t" 25 26 /* This macro is also expanded on the Rust side. */ 27 #define ARCH_STATIC_BRANCH_ASM(key, label) \ 28 " .align 2 \n\t" \ 29 " .option push \n\t" \ 30 " .option norelax \n\t" \ 31 " .option norvc \n\t" \ 32 "1: nop \n\t" \ 33 " .option pop \n\t" \ 34 JUMP_TABLE_ENTRY(key, label) 35 36 static __always_inline bool arch_static_branch(struct static_key * const key, 37 const bool branch) 38 { 39 asm goto( 40 ARCH_STATIC_BRANCH_ASM("%0", "%l[label]") 41 : : "i"(&((char *)key)[branch]) : : label); 42 43 return false; 44 label: 45 return true; 46 } 47 48 #define ARCH_STATIC_BRANCH_JUMP_ASM(key, label) \ 49 " .align 2 \n\t" \ 50 " .option push \n\t" \ 51 " .option norelax \n\t" \ 52 " .option norvc \n\t" \ 53 "1: j " label " \n\t" \ 54 " .option pop \n\t" \ 55 JUMP_TABLE_ENTRY(key, label) 56 57 static __always_inline bool arch_static_branch_jump(struct static_key * const key, 58 const bool branch) 59 { 60 asm goto( 61 ARCH_STATIC_BRANCH_JUMP_ASM("%0", "%l[label]") 62 : : "i"(&((char *)key)[branch]) : : label); 63 64 return false; 65 label: 66 return true; 67 } 68 69 #endif /* __ASSEMBLY__ */ 70 #endif /* __ASM_JUMP_LABEL_H */ 71