44 строки
1.2 KiB
C
44 строки
1.2 KiB
C
/*
|
|
* 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;
|
|
}
|