/* $NetBSD: fixup.c,v 1.10 2014/08/02 15:58:04 joerg Exp $ */
/*-
* Copyright (c) 2010, 2011 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Raytheon BBN Technologies Corp and Defense Advanced Research Projects
* Agency and which was developed by Matt Thomas of 3am Software Foundry.
*
* This material is based upon work supported by the Defense Advanced Research
* Projects Agency and Space and Naval Warfare Systems Center, Pacific, under
* Contract No. N66001-09-C-2073.
* Approved for Public Release, Distribution Unlimited
*
* 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.
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: fixup.c,v 1.10 2014/08/02 15:58:04 joerg Exp $");
#include <sys/param.h>
#include <sys/types.h>
#include <powerpc/instr.h>
#include <powerpc/spr.h>
#include <powerpc/include/cpu.h>
#include <powerpc/include/oea/spr.h>
static inline void
fixup_jump(uint32_t *insnp, const struct powerpc_jump_fixup_info *jfi)
{
union instr instr = { .i_int = *insnp };
KASSERT(instr.i_any.i_opcd == OPC_B);
instr.i_i.i_li = jfi->jfi_real - fixup_addr2offset(insnp);
*insnp = instr.i_int;
__asm(
"dcbst 0,%0" "\n\t"
"sync" "\n\t"
"icbi 0,%0" "\n\t"
"sync" "\n\t"
"isync"
:: "b"(insnp));
}
void
powerpc_fixup_stubs(uint32_t *start, uint32_t *end,
uint32_t *stub_start, uint32_t *stub_end)
{
extern uint32_t __stub_start[], __stub_end[];
#ifdef DEBUG
size_t fixups_done = 0;
uint64_t cycles = 0;
#ifdef PPC_OEA601
if ((mfpvr() >> 16) == MPC601)
cycles = rtc_nanosecs() >> 7;
else
#endif
cycles = mftb();
#endif
if (stub_start == NULL) {
stub_start = __stub_start;
stub_end = __stub_end;
}
if (end > __stub_start)
end = __stub_start;
for (uint32_t *insnp = start; insnp < end; insnp++) {
struct powerpc_jump_fixup_info fixup;
union instr instr = { .i_int = *insnp };
uint32_t *stub = insnp + instr.i_i.i_li;
u_int opcode = instr.i_any.i_opcd;
/*
* First we check to see if this is a jump and whether it is
* within the range we are interested in.
*/
if (opcode != OPC_B || stub < stub_start || stub_end <= stub)
continue;
fixup.jfi_stub = fixup_addr2offset(stub);
fixup.jfi_real = 0;
/*
* We know it's a jump, now we need to figure out where it goes.
*/
register_t fixreg[32];
register_t ctr = 0;
uint32_t valid_mask = (1 << 1);
#ifdef DIAGNOSTIC
int r_lr = -1;
#endif
for (; stub < stub_end && fixup.jfi_real == 0; stub++) {
const union instr i = { .i_int = *stub };
switch (i.i_any.i_opcd) {
case OPC_integer_31: {
const u_int rs = i.i_x.i_rs;
const u_int ra = i.i_x.i_ra;
const u_int rb = i.i_x.i_rb;
switch (i.i_x.i_xo) {
case OPC31_MFSPR: {
#ifdef DIAGNOSTIC
const u_int spr = (rb << 5) | ra;
KASSERT(spr == SPR_LR);
r_lr = rs;
#endif
valid_mask |= (1 << rs);
break;
}
case OPC31_MTSPR: {
#ifdef DIAGNOSTIC
const u_int spr = (rb << 5) | ra;
KASSERT(valid_mask & (1 << rs));
KASSERT(spr == SPR_CTR);
#endif
ctr = fixreg[rs];
break;
}
case OPC31_OR: {
#ifdef DIAGNOSTIC
KASSERT(valid_mask & (1 << rs));
KASSERT(valid_mask & (1 << rb));
#endif
fixreg[ra] = fixreg[rs] | fixreg[rb];
valid_mask |= 1 << ra;
break;
}
default:
panic("%s: %p: unexpected insn 0x%08x",
__func__, stub, i.i_int);
}
break;
}
case OPC_ADDI:
case OPC_ADDIS: {
const u_int rs = i.i_d.i_rs;
const u_int ra = i.i_d.i_ra;
register_t d = i.i_d.i_d << ((i.i_d.i_opcd & 1) * 16);
if (ra) {
KASSERT(valid_mask & (1 << ra));
d += fixreg[ra];
}
fixreg[rs] = d;
valid_mask |= (1 << rs);
break;
}
case OPC_LWZ: {
const u_int rs = i.i_d.i_rs;
const u_int ra = i.i_d.i_ra;
register_t addr = i.i_d.i_d;
if (ra) {
KASSERT(valid_mask & (1 << ra));
addr += fixreg[ra];
}
fixreg[rs] = *(uint32_t *)addr;
valid_mask |= (1 << rs);
break;
}
case OPC_STW: {
KASSERT((i.i_d.i_rs == r_lr || i.i_d.i_rs == 31) && i.i_d.i_ra == 1);
break;
}
case OPC_STWU: {
KASSERT(i.i_d.i_rs == 1 && i.i_d.i_ra == 1);
KASSERT(i.i_d.i_d < 0);
break;
}
case OPC_branch_19: {
KASSERT(r_lr == -1 || i.i_int == 0x4e800421);
KASSERT(r_lr != -1 || i.i_int == 0x4e800420);
if (ctr == 0) {
panic("%s: jump at %p to %p would "
"branch to 0", __func__, insnp,
insnp + instr.i_i.i_li);
}
fixup.jfi_real = fixup_addr2offset(ctr);
break;
}
case OPC_RLWINM: {
// LLVM emits these for bool operands.
// Ignore them.
break;
}
default: {
panic("%s: %p: unexpected insn 0x%08x",
__func__, stub, i.i_int);
}
}
}
KASSERT(fixup.jfi_real != 0);
/*
* Now we know the real destination to branch to. Replace the
* old displacement with the new displacement.
*/
#if 0
printf("%s: %p: change from %#x to %#x\n",
__func__, insnp, fixup.jfi_stub << 2, fixup.jfi_real << 2);
#endif
fixup_jump(insnp, &fixup);
#ifdef DEBUG
fixups_done++;
#endif
}
#ifdef DEBUG
#ifdef PPC_OEA601
if ((mfpvr() >> 16) == MPC601)
cycles = (rtc_nanosecs() >> 7) - cycles;
else
#endif
cycles = mftb() - cycles;
printf("%s: %zu fixup%s done in %"PRIu64" cycles\n", __func__,
fixups_done, fixups_done == 1 ? "" : "s",
cycles);
#endif
}
void
cpu_fixup_stubs(void)
{
extern uint32_t _ftext[];
extern uint32_t _etext[];
powerpc_fixup_stubs(_ftext, _etext, NULL, NULL);
}