1 /* 2 * This file is subject to the terms and conditions of the GNU General Public 3 * License. See the file "COPYING" in the main directory of this archive 4 * for more details. 5 * 6 * Copyright (c) 2010 Cavium Networks, Inc. 7 */ 8 9 #include <linux/jump_label.h> 10 #include <linux/kernel.h> 11 #include <linux/memory.h> 12 #include <linux/mutex.h> 13 #include <linux/types.h> 14 #include <linux/cpu.h> 15 16 #include <asm/cacheflush.h> 17 #include <asm/inst.h> 18 19 #ifdef HAVE_JUMP_LABEL 20 21 /* 22 * Define parameters for the standard MIPS and the microMIPS jump 23 * instruction encoding respectively: 24 * 25 * - the ISA bit of the target, either 0 or 1 respectively, 26 * 27 * - the amount the jump target address is shifted right to fit in the 28 * immediate field of the machine instruction, either 2 or 1, 29 * 30 * - the mask determining the size of the jump region relative to the 31 * delay-slot instruction, either 256MB or 128MB, 32 * 33 * - the jump target alignment, either 4 or 2 bytes. 34 */ 35 #define J_ISA_BIT IS_ENABLED(CONFIG_CPU_MICROMIPS) 36 #define J_RANGE_SHIFT (2 - J_ISA_BIT) 37 #define J_RANGE_MASK ((1ul << (26 + J_RANGE_SHIFT)) - 1) 38 #define J_ALIGN_MASK ((1ul << J_RANGE_SHIFT) - 1) 39 40 void arch_jump_label_transform(struct jump_entry *e, 41 enum jump_label_type type) 42 { 43 union mips_instruction *insn_p; 44 union mips_instruction insn; 45 46 insn_p = (union mips_instruction *)msk_isa16_mode(e->code); 47 48 /* Jump only works within an aligned region its delay slot is in. */ 49 BUG_ON((e->target & ~J_RANGE_MASK) != ((e->code + 4) & ~J_RANGE_MASK)); 50 51 /* Target must have the right alignment and ISA must be preserved. */ 52 BUG_ON((e->target & J_ALIGN_MASK) != J_ISA_BIT); 53 54 if (type == JUMP_LABEL_JMP) { 55 insn.j_format.opcode = J_ISA_BIT ? mm_j32_op : j_op; 56 insn.j_format.target = e->target >> J_RANGE_SHIFT; 57 } else { 58 insn.word = 0; /* nop */ 59 } 60 61 mutex_lock(&text_mutex); 62 if (IS_ENABLED(CONFIG_CPU_MICROMIPS)) { 63 insn_p->halfword[0] = insn.word >> 16; 64 insn_p->halfword[1] = insn.word; 65 } else 66 *insn_p = insn; 67 68 flush_icache_range((unsigned long)insn_p, 69 (unsigned long)insn_p + sizeof(*insn_p)); 70 71 mutex_unlock(&text_mutex); 72 } 73 74 #endif /* HAVE_JUMP_LABEL */ 75