e7a57273c6
Currently create_branch() creates a branch instruction for you, and patches it into the call site. In some circumstances it would be nice to be able to create the instruction and patch it later, and also some code might want to check for errors in the branch creation before doing the patching. A future commit will change create_branch() to check for errors. For callers that don't care, replace create_branch() with patch_branch(), which just creates the branch and patches it directly. While we're touching all the callers, change to using unsigned int *, as this seems to match usage better. That allows (and requires) us to remove the volatile in the definition of vector in powermac/smp.c and mpc86xx_smp.c, that's correct because now that we're passing vector as an unsigned int * the compiler knows that it's value might change across the patch_branch() call. Signed-off-by: Michael Ellerman <michael@ellerman.id.au> Acked-by: Kumar Gala <galak@kernel.crashing.org> Acked-by: Jon Loeliger <jdl@freescale.com> Signed-off-by: Paul Mackerras <paulus@samba.org>
38 lines
1.0 KiB
C
38 lines
1.0 KiB
C
/*
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* Copyright 2008 Michael Ellerman, IBM Corporation.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#include <linux/kernel.h>
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#include <asm/code-patching.h>
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void patch_instruction(unsigned int *addr, unsigned int instr)
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{
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*addr = instr;
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asm ("dcbst 0, %0; sync; icbi 0,%0; sync; isync" : : "r" (addr));
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}
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void patch_branch(unsigned int *addr, unsigned long target, int flags)
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{
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patch_instruction(addr, create_branch(addr, target, flags));
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}
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unsigned int create_branch(const unsigned int *addr,
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unsigned long target, int flags)
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{
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unsigned int instruction;
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if (! (flags & BRANCH_ABSOLUTE))
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target = target - (unsigned long)addr;
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/* Mask out the flags and target, so they don't step on each other. */
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instruction = 0x48000000 | (flags & 0x3) | (target & 0x03FFFFFC);
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return instruction;
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}
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