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arch/mips/kernel/jump_label.c 1.27 KB
94bb0c1ab   David Daney   MIPS: jump label:...
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  /*
   * 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>
  
  #ifdef HAVE_JUMP_LABEL
  
  #define J_RANGE_MASK ((1ul << 28) - 1)
  
  void arch_jump_label_transform(struct jump_entry *e,
  			       enum jump_label_type type)
  {
  	union mips_instruction insn;
  	union mips_instruction *insn_p =
  		(union mips_instruction *)(unsigned long)e->code;
  
  	/* Jump only works within a 256MB aligned region. */
  	BUG_ON((e->target & ~J_RANGE_MASK) != (e->code & ~J_RANGE_MASK));
  
  	/* Target must have 4 byte alignment. */
  	BUG_ON((e->target & 3) != 0);
  
  	if (type == JUMP_LABEL_ENABLE) {
  		insn.j_format.opcode = j_op;
  		insn.j_format.target = (e->target & J_RANGE_MASK) >> 2;
  	} else {
  		insn.word = 0; /* nop */
  	}
  
  	get_online_cpus();
  	mutex_lock(&text_mutex);
  	*insn_p = insn;
  
  	flush_icache_range((unsigned long)insn_p,
  			   (unsigned long)insn_p + sizeof(*insn_p));
  
  	mutex_unlock(&text_mutex);
  	put_online_cpus();
  }
  
  #endif /* HAVE_JUMP_LABEL */