/* * This file is subject to the terms and conditions of the GNU General Public * License.  See the file "COPYING" in the main directory of this archive * for more details. * * Copyright (c) 2010 Cavium Networks, Inc. */ #include <linux/jump_label.h>#include <linux/kernel.h>#include <linux/memory.h>#include <linux/mutex.h>#include <linux/types.h>#include <linux/cpu.h> #include <asm/cacheflush.h>#include <asm/inst.h> /* * Define parameters for the standard MIPS and the microMIPS jump * instruction encoding respectively: * * - the ISA bit of the target, either 0 or 1 respectively, * * - the amount the jump target address is shifted right to fit in the *   immediate field of the machine instruction, either 2 or 1, * * - the mask determining the size of the jump region relative to the *   delay-slot instruction, either 256MB or 128MB, * * - the jump target alignment, either 4 or 2 bytes. */#define J_ISA_BIT	IS_ENABLED(CONFIG_CPU_MICROMIPS)#define J_RANGE_SHIFT	(2 - J_ISA_BIT)#define J_RANGE_MASK	((1ul << (26 + J_RANGE_SHIFT)) - 1)#define J_ALIGN_MASK	((1ul << J_RANGE_SHIFT) - 1) void arch_jump_label_transform(struct jump_entry *e,			       enum jump_label_type type){	union mips_instruction *insn_p;	union mips_instruction insn;	long offset; 	insn_p = (union mips_instruction *)msk_isa16_mode(e->code); 	/* Target must have the right alignment and ISA must be preserved. */	BUG_ON((e->target & J_ALIGN_MASK) != J_ISA_BIT); 	if (type == JUMP_LABEL_JMP) {		if (!IS_ENABLED(CONFIG_CPU_MICROMIPS) && MIPS_ISA_REV >= 6) {			offset = e->target - ((unsigned long)insn_p + 4);			offset >>= 2; 			/*			 * The branch offset must fit in the instruction's 26			 * bit field.			 */			WARN_ON((offset >= (long)BIT(25)) ||				(offset < -(long)BIT(25))); 			insn.j_format.opcode = bc6_op;			insn.j_format.target = offset;		} else {			/*			 * Jump only works within an aligned region its delay			 * slot is in.			 */			WARN_ON((e->target & ~J_RANGE_MASK) !=				((e->code + 4) & ~J_RANGE_MASK)); 			insn.j_format.opcode = J_ISA_BIT ? mm_j32_op : j_op;			insn.j_format.target = e->target >> J_RANGE_SHIFT;		}	} else {		insn.word = 0; /* nop */	} 	mutex_lock(&text_mutex);	if (IS_ENABLED(CONFIG_CPU_MICROMIPS)) {		insn_p->halfword[0] = insn.word >> 16;		insn_p->halfword[1] = insn.word;	} else		*insn_p = insn; 	flush_icache_range((unsigned long)insn_p,			   (unsigned long)insn_p + sizeof(*insn_p)); 	mutex_unlock(&text_mutex);} #ifdef CONFIG_MODULESvoid jump_label_apply_nops(struct module *mod){	struct jump_entry *iter_start = mod->jump_entries;	struct jump_entry *iter_stop = iter_start + mod->num_jump_entries;	struct jump_entry *iter; 	/* if the module doesn't have jump label entries, just return */	if (iter_start == iter_stop)		return; 	for (iter = iter_start; iter < iter_stop; iter++) {		/* Only write NOPs for arch_branch_static(). */		if (jump_label_init_type(iter) == JUMP_LABEL_NOP)			arch_jump_label_transform(iter, JUMP_LABEL_NOP);	}}#endif