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/*
* Copyright 2008 Michael Ellerman, IBM Corporation.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#include <linux/kernel.h>
#include <asm/code-patching.h>
void patch_instruction(unsigned int *addr, unsigned int instr)
{
*addr = instr;
asm ("dcbst 0, %0; sync; icbi 0,%0; sync; isync" : : "r" (addr));
}
void patch_branch(unsigned int *addr, unsigned long target, int flags)
{
patch_instruction(addr, create_branch(addr, target, flags));
}
unsigned int create_branch(const unsigned int *addr,
unsigned long target, int flags)
{
unsigned int instruction;
long offset;
offset = target;
if (! (flags & BRANCH_ABSOLUTE))
offset = offset - (unsigned long)addr;
/* Check we can represent the target in the instruction format */
if (offset < -0x2000000 || offset > 0x1fffffc || offset & 0x3)
return 0;
/* Mask out the flags and target, so they don't step on each other. */
instruction = 0x48000000 | (flags & 0x3) | (offset & 0x03FFFFFC);
return instruction;
}
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