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/*
* Altera Nios II MMU emulation for qemu.
*
* Copyright (C) 2012 Chris Wulff <crwulff@gmail.com>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, see
* <http://www.gnu.org/licenses/lgpl-2.1.html>
*/
#include "qemu/osdep.h"
#include "qemu/qemu-print.h"
#include "cpu.h"
#include "exec/exec-all.h"
#include "mmu.h"
#include "exec/helper-proto.h"
#include "trace/trace-target_nios2.h"
/* rw - 0 = read, 1 = write, 2 = fetch. */
unsigned int mmu_translate(CPUNios2State *env,
Nios2MMULookup *lu,
target_ulong vaddr, int rw, int mmu_idx)
{
Nios2CPU *cpu = env_archcpu(env);
int pid = FIELD_EX32(env->mmu.tlbmisc_wr, CR_TLBMISC, PID);
int vpn = vaddr >> 12;
int way, n_ways = cpu->tlb_num_ways;
for (way = 0; way < n_ways; way++) {
uint32_t index = (way * n_ways) + (vpn & env->mmu.tlb_entry_mask);
Nios2TLBEntry *entry = &env->mmu.tlb[index];
if (((entry->tag >> 12) != vpn) ||
(((entry->tag & (1 << 11)) == 0) &&
((entry->tag & ((1 << cpu->pid_num_bits) - 1)) != pid))) {
trace_nios2_mmu_translate_miss(vaddr, pid, index, entry->tag);
continue;
}
lu->vaddr = vaddr & TARGET_PAGE_MASK;
lu->paddr = FIELD_EX32(entry->data, CR_TLBACC, PFN) << TARGET_PAGE_BITS;
lu->prot = ((entry->data & CR_TLBACC_R) ? PAGE_READ : 0) |
((entry->data & CR_TLBACC_W) ? PAGE_WRITE : 0) |
((entry->data & CR_TLBACC_X) ? PAGE_EXEC : 0);
trace_nios2_mmu_translate_hit(vaddr, pid, index, lu->paddr, lu->prot);
return 1;
}
return 0;
}
static void mmu_flush_pid(CPUNios2State *env, uint32_t pid)
{
CPUState *cs = env_cpu(env);
Nios2CPU *cpu = env_archcpu(env);
int idx;
for (idx = 0; idx < cpu->tlb_num_entries; idx++) {
Nios2TLBEntry *entry = &env->mmu.tlb[idx];
if ((entry->tag & (1 << 10)) && (!(entry->tag & (1 << 11))) &&
((entry->tag & ((1 << cpu->pid_num_bits) - 1)) == pid)) {
uint32_t vaddr = entry->tag & TARGET_PAGE_MASK;
trace_nios2_mmu_flush_pid_hit(pid, idx, vaddr);
tlb_flush_page(cs, vaddr);
} else {
trace_nios2_mmu_flush_pid_miss(pid, idx, entry->tag);
}
}
}
void helper_mmu_write_tlbacc(CPUNios2State *env, uint32_t v)
{
CPUState *cs = env_cpu(env);
Nios2CPU *cpu = env_archcpu(env);
trace_nios2_mmu_write_tlbacc(FIELD_EX32(v, CR_TLBACC, IG),
(v & CR_TLBACC_C) ? 'C' : '.',
(v & CR_TLBACC_R) ? 'R' : '.',
(v & CR_TLBACC_W) ? 'W' : '.',
(v & CR_TLBACC_X) ? 'X' : '.',
(v & CR_TLBACC_G) ? 'G' : '.',
FIELD_EX32(v, CR_TLBACC, PFN));
/* if tlbmisc.WE == 1 then trigger a TLB write on writes to TLBACC */
if (env->ctrl[CR_TLBMISC] & CR_TLBMISC_WE) {
int way = FIELD_EX32(env->ctrl[CR_TLBMISC], CR_TLBMISC, WAY);
int vpn = FIELD_EX32(env->mmu.pteaddr_wr, CR_PTEADDR, VPN);
int pid = FIELD_EX32(env->mmu.tlbmisc_wr, CR_TLBMISC, PID);
int g = FIELD_EX32(v, CR_TLBACC, G);
int valid = FIELD_EX32(vpn, CR_TLBACC, PFN) < 0xC0000;
Nios2TLBEntry *entry =
&env->mmu.tlb[(way * cpu->tlb_num_ways) +
(vpn & env->mmu.tlb_entry_mask)];
uint32_t newTag = (vpn << 12) | (g << 11) | (valid << 10) | pid;
uint32_t newData = v & (CR_TLBACC_C | CR_TLBACC_R | CR_TLBACC_W |
CR_TLBACC_X | R_CR_TLBACC_PFN_MASK);
if ((entry->tag != newTag) || (entry->data != newData)) {
if (entry->tag & (1 << 10)) {
/* Flush existing entry */
tlb_flush_page(cs, entry->tag & TARGET_PAGE_MASK);
}
entry->tag = newTag;
entry->data = newData;
}
/* Auto-increment tlbmisc.WAY */
env->ctrl[CR_TLBMISC] = FIELD_DP32(env->ctrl[CR_TLBMISC],
CR_TLBMISC, WAY,
(way + 1) & (cpu->tlb_num_ways - 1));
}
/* Writes to TLBACC don't change the read-back value */
env->mmu.tlbacc_wr = v;
}
void helper_mmu_write_tlbmisc(CPUNios2State *env, uint32_t v)
{
Nios2CPU *cpu = env_archcpu(env);
uint32_t new_pid = FIELD_EX32(v, CR_TLBMISC, PID);
uint32_t old_pid = FIELD_EX32(env->mmu.tlbmisc_wr, CR_TLBMISC, PID);
uint32_t way = FIELD_EX32(v, CR_TLBMISC, WAY);
trace_nios2_mmu_write_tlbmisc(way,
(v & CR_TLBMISC_RD) ? 'R' : '.',
(v & CR_TLBMISC_WE) ? 'W' : '.',
(v & CR_TLBMISC_DBL) ? '2' : '.',
(v & CR_TLBMISC_BAD) ? 'B' : '.',
(v & CR_TLBMISC_PERM) ? 'P' : '.',
(v & CR_TLBMISC_D) ? 'D' : '.',
new_pid);
if (new_pid != old_pid) {
mmu_flush_pid(env, old_pid);
}
/* if tlbmisc.RD == 1 then trigger a TLB read on writes to TLBMISC */
if (v & CR_TLBMISC_RD) {
int vpn = FIELD_EX32(env->mmu.pteaddr_wr, CR_PTEADDR, VPN);
Nios2TLBEntry *entry =
&env->mmu.tlb[(way * cpu->tlb_num_ways) +
(vpn & env->mmu.tlb_entry_mask)];
env->ctrl[CR_TLBACC] &= R_CR_TLBACC_IG_MASK;
env->ctrl[CR_TLBACC] |= entry->data;
env->ctrl[CR_TLBACC] |= (entry->tag & (1 << 11)) ? CR_TLBACC_G : 0;
env->ctrl[CR_TLBMISC] = FIELD_DP32(v, CR_TLBMISC, PID,
entry->tag &
((1 << cpu->pid_num_bits) - 1));
env->ctrl[CR_PTEADDR] = FIELD_DP32(env->ctrl[CR_PTEADDR],
CR_PTEADDR, VPN,
entry->tag >> TARGET_PAGE_BITS);
} else {
env->ctrl[CR_TLBMISC] = v;
}
env->mmu.tlbmisc_wr = v;
}
void helper_mmu_write_pteaddr(CPUNios2State *env, uint32_t v)
{
trace_nios2_mmu_write_pteaddr(FIELD_EX32(v, CR_PTEADDR, PTBASE),
FIELD_EX32(v, CR_PTEADDR, VPN));
/* Writes to PTEADDR don't change the read-back VPN value */
env->ctrl[CR_PTEADDR] = ((v & ~R_CR_PTEADDR_VPN_MASK) |
(env->ctrl[CR_PTEADDR] & R_CR_PTEADDR_VPN_MASK));
env->mmu.pteaddr_wr = v;
}
void mmu_init(CPUNios2State *env)
{
Nios2CPU *cpu = env_archcpu(env);
Nios2MMU *mmu = &env->mmu;
mmu->tlb_entry_mask = (cpu->tlb_num_entries / cpu->tlb_num_ways) - 1;
mmu->tlb = g_new0(Nios2TLBEntry, cpu->tlb_num_entries);
}
void dump_mmu(CPUNios2State *env)
{
Nios2CPU *cpu = env_archcpu(env);
int i;
qemu_printf("MMU: ways %d, entries %d, pid bits %d\n",
cpu->tlb_num_ways, cpu->tlb_num_entries,
cpu->pid_num_bits);
for (i = 0; i < cpu->tlb_num_entries; i++) {
Nios2TLBEntry *entry = &env->mmu.tlb[i];
qemu_printf("TLB[%d] = %08X %08X %c VPN %05X "
"PID %02X %c PFN %05X %c%c%c%c\n",
i, entry->tag, entry->data,
(entry->tag & (1 << 10)) ? 'V' : '-',
entry->tag >> 12,
entry->tag & ((1 << cpu->pid_num_bits) - 1),
(entry->tag & (1 << 11)) ? 'G' : '-',
FIELD_EX32(entry->data, CR_TLBACC, PFN),
(entry->data & CR_TLBACC_C) ? 'C' : '-',
(entry->data & CR_TLBACC_R) ? 'R' : '-',
(entry->data & CR_TLBACC_W) ? 'W' : '-',
(entry->data & CR_TLBACC_X) ? 'X' : '-');
}
}
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