/* $NetBSD: elf_support.h,v 1.1 2018/03/29 13:23:40 joerg Exp $ */

/* $NetBSD: elf_support.h,v 1.1 2018/03/29 13:23:40 joerg Exp $ */

/*-
* Copyright (c) 2000 Eduardo Horvath.
* Copyright (c) 2018 The NetBSD Foundation, Inc.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef _SPARC64_ELF_SUPPORT_H
#define _SPARC64_ELF_SUPPORT_H

#ifdef __arch64__
/*
* Create a jump to the location `target` starting at `where`.
* This requires up to 6 instructions.
* The first instruction is written last as it replaces a branch
* in the PLT during lazy binding.
* The resulting code can trash %g1 and %g5.
*/
static inline void
sparc_write_branch(void *where_, void *target)
{
const unsigned int BAA = 0x30800000U; /* ba,a (offset / 4) */
const unsigned int SETHI = 0x03000000U; /* sethi %hi(0), %g1 */
const unsigned int JMP = 0x81c06000U; /* jmpl %g1+%lo(0), %g0 */
const unsigned int OR = 0x82106000U; /* or %g1, 0, %g1 */
const unsigned int XOR = 0x82186000U; /* xor %g1, 0, %g1 */
const unsigned int MOV71 = 0x8213e000U; /* or %o7, 0, %g1 */
const unsigned int MOV17 = 0x9e106000U; /* or %g1, 0, %o7 */
const unsigned int CALL = 0x40000000U; /* call 0 */
const unsigned int SLLX = 0x83287000U; /* sllx %g1, 0, %g1 */
const unsigned int NEG = 0x82200001U; /* neg %g1 */
const unsigned int SETHIG5 = 0x0b000000U; /* sethi %hi(0), %g5 */
const unsigned int ORG5 = 0x82104005U; /* or %g1, %g5, %g1 */

unsigned int *where = (unsigned int *)where_;
unsigned long value = (unsigned long)target;
unsigned long offset = value - (unsigned long)where;

#define HIVAL(v, s) (((v) >> (s)) & 0x003fffffU)
#define LOVAL(v, s) (((v) >> (s)) & 0x000003ffU)
if (offset + 0x800000 <= 0x7ffffc) {
/* Displacement is within 8MB, use a direct branch. */
where[0] = BAA | ((offset >> 2) & 0x3fffff);
__asm volatile("iflush %0+0" : : "r" (where));
return;
}

if (value <= 0xffffffffUL) {
/*
* The absolute address is a 32bit value.
* This can be encoded as:
* sethi %hi(value), %g1
* jmp %g1+%lo(value)
*/
where[1] = JMP | LOVAL(value, 0);
__asm volatile("iflush %0+4" : : "r" (where));
where[0] = SETHI | HIVAL(value, 10);
__asm volatile("iflush %0+0" : : "r" (where));
return;
}

if (value >= 0xffffffff00000000UL) {
/*
* The top 32bit address range can be encoded as:
* sethi %hix(addr), %g1
* xor %g1, %lox(addr), %g1
* jmp %g1
*/
where[2] = JMP;
where[1] = XOR | (value & 0x00003ff) | 0x1c00;
__asm volatile("iflush %0+4" : : "r" (where));
__asm volatile("iflush %0+8" : : "r" (where));
where[0] = SETHI | HIVAL(~value, 10);
__asm volatile("iflush %0+0" : : "r" (where));
return;
}

if ((offset + 4) + 0x80000000UL <= 0x100000000UL) {
/*
* Displacement of the second instruction is within
* +-2GB. This can use a direct call instruction:
* mov %o7, %g1
* call (value - .)
* mov %g1, %o7
*/
where[1] = CALL | ((-(offset + 4)>> 2) & 0x3fffffffU);
where[2] = MOV17;
__asm volatile("iflush %0+4" : : "r" (where));
__asm volatile("iflush %0+8" : : "r" (where));
where[0] = MOV71;
__asm volatile("iflush %0+0" : : "r" (where));
return;
}

if (value < 0x100000000000UL) {
/*
* The absolute address is a 44bit value.
* This can be encoded as:
* sethi %h44(addr), %g1
* or %g1, %m44(addr), %g1
* sllx %g1, 12, %g1
* jmp %g1+%l44(addr)
*/
where[1] = OR | (((value) >> 12) & 0x00001fff);
where[2] = SLLX | 12;
where[3] = JMP | LOVAL(value, 0);
__asm volatile("iflush %0+4" : : "r" (where));
__asm volatile("iflush %0+8" : : "r" (where));
__asm volatile("iflush %0+12" : : "r" (where));
where[0] = SETHI | HIVAL(value, 22);
__asm volatile("iflush %0+0" : : "r" (where));
return;
}

if (value > 0xfffff00000000000UL) {
/*
* The top 44bit address range can be encoded as:
* sethi %hi((-addr)>>12), %g1
* or %g1, %lo((-addr)>>12), %g1
* neg %g1
* sllx %g1, 12, %g1
* jmp %g1+(addr&0x0fff)
*/
unsigned long neg = (-value)>>12;
where[1] = OR | (LOVAL(neg, 0)+1);
where[2] = NEG;
where[3] = SLLX | 12;
where[4] = JMP | (value & 0x0fff);
__asm volatile("iflush %0+4" : : "r" (where));
__asm volatile("iflush %0+8" : : "r" (where));
__asm volatile("iflush %0+12" : : "r" (where));
__asm volatile("iflush %0+16" : : "r" (where));
where[0] = SETHI | HIVAL(neg, 10);
__asm volatile("iflush %0+0" : : "r" (where));
return;
}

/*
* The general case of a 64bit address is encoded as:
* sethi %hh(addr), %g1
* sethi %lm(addr), %g5
* or %g1, %hm(addr), %g1
* sllx %g1, 32, %g1
* or %g1, %g5, %g1
* jmp %g1+%lo(addr)
*/
where[1] = SETHIG5 | HIVAL(value, 10);
where[2] = OR | LOVAL(value, 32);
where[3] = SLLX | 32;
where[4] = ORG5;
where[5] = JMP | LOVAL(value, 0);
__asm volatile("iflush %0+4" : : "r" (where));
__asm volatile("iflush %0+8" : : "r" (where));
__asm volatile("iflush %0+12" : : "r" (where));
__asm volatile("iflush %0+16" : : "r" (where));
__asm volatile("iflush %0+20" : : "r" (where));
where[0] = SETHI | HIVAL(value, 42);
__asm volatile("iflush %0+0" : : "r" (where));
#undef HIVAL
#undef LOVAL
}
#else
#include <sparc/elf_support.h>
#endif
#endif