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/*
* Microblaze MMU emulation for qemu.
*
* Copyright (c) 2009 Edgar E. Iglesias
*
* 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 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/>.
*/
#include "cpu.h"
#define D(x)
static unsigned int tlb_decode_size(unsigned int f)
{
static const unsigned int sizes[] = {
1 * 1024, 4 * 1024, 16 * 1024, 64 * 1024, 256 * 1024,
1 * 1024 * 1024, 4 * 1024 * 1024, 16 * 1024 * 1024
};
assert(f < ARRAY_SIZE(sizes));
return sizes[f];
}
static void mmu_flush_idx(CPUState *env, unsigned int idx)
{
struct microblaze_mmu *mmu = &env->mmu;
unsigned int tlb_size;
uint32_t tlb_tag, end, t;
t = mmu->rams[RAM_TAG][idx];
if (!(t & TLB_VALID))
return;
tlb_tag = t & TLB_EPN_MASK;
tlb_size = tlb_decode_size((t & TLB_PAGESZ_MASK) >> 7);
end = tlb_tag + tlb_size;
while (tlb_tag < end) {
tlb_flush_page(env, tlb_tag);
tlb_tag += TARGET_PAGE_SIZE;
}
}
static void mmu_change_pid(CPUState *env, unsigned int newpid)
{
struct microblaze_mmu *mmu = &env->mmu;
unsigned int i;
uint32_t t;
if (newpid & ~0xff)
qemu_log("Illegal rpid=%x\n", newpid);
for (i = 0; i < ARRAY_SIZE(mmu->rams[RAM_TAG]); i++) {
/* Lookup and decode. */
t = mmu->rams[RAM_TAG][i];
if (t & TLB_VALID) {
if (mmu->tids[i] && ((mmu->regs[MMU_R_PID] & 0xff) == mmu->tids[i]))
mmu_flush_idx(env, i);
}
}
}
/* rw - 0 = read, 1 = write, 2 = fetch. */
unsigned int mmu_translate(struct microblaze_mmu *mmu,
struct microblaze_mmu_lookup *lu,
target_ulong vaddr, int rw, int mmu_idx)
{
unsigned int i, hit = 0;
unsigned int tlb_ex = 0, tlb_wr = 0, tlb_zsel;
unsigned int tlb_size;
uint32_t tlb_tag, tlb_rpn, mask, t0;
lu->err = ERR_MISS;
for (i = 0; i < ARRAY_SIZE(mmu->rams[RAM_TAG]); i++) {
uint32_t t, d;
/* Lookup and decode. */
t = mmu->rams[RAM_TAG][i];
D(qemu_log("TLB %d valid=%d\n", i, t & TLB_VALID));
if (t & TLB_VALID) {
tlb_size = tlb_decode_size((t & TLB_PAGESZ_MASK) >> 7);
if (tlb_size < TARGET_PAGE_SIZE) {
qemu_log("%d pages not supported\n", tlb_size);
abort();
}
mask = ~(tlb_size - 1);
tlb_tag = t & TLB_EPN_MASK;
if ((vaddr & mask) != (tlb_tag & mask)) {
D(qemu_log("TLB %d vaddr=%x != tag=%x\n",
i, vaddr & mask, tlb_tag & mask));
continue;
}
if (mmu->tids[i]
&& ((mmu->regs[MMU_R_PID] & 0xff) != mmu->tids[i])) {
D(qemu_log("TLB %d pid=%x != tid=%x\n",
i, mmu->regs[MMU_R_PID], mmu->tids[i]));
continue;
}
/* Bring in the data part. */
d = mmu->rams[RAM_DATA][i];
tlb_ex = d & TLB_EX;
tlb_wr = d & TLB_WR;
/* Now lets see if there is a zone that overrides the protbits. */
tlb_zsel = (d >> 4) & 0xf;
t0 = mmu->regs[MMU_R_ZPR] >> (30 - (tlb_zsel * 2));
t0 &= 0x3;
if (tlb_zsel > mmu->c_mmu_zones) {
qemu_log("tlb zone select out of range! %d\n", tlb_zsel);
t0 = 1; /* Ignore. */
}
if (mmu->c_mmu == 1) {
t0 = 1; /* Zones are disabled. */
}
switch (t0) {
case 0:
if (mmu_idx == MMU_USER_IDX)
continue;
break;
case 2:
if (mmu_idx != MMU_USER_IDX) {
tlb_ex = 1;
tlb_wr = 1;
}
break;
case 3:
tlb_ex = 1;
tlb_wr = 1;
break;
default: break;
}
lu->err = ERR_PROT;
lu->prot = PAGE_READ;
if (tlb_wr)
lu->prot |= PAGE_WRITE;
else if (rw == 1)
goto done;
if (tlb_ex)
lu->prot |=PAGE_EXEC;
else if (rw == 2) {
goto done;
}
tlb_rpn = d & TLB_RPN_MASK;
lu->vaddr = tlb_tag;
lu->paddr = tlb_rpn;
lu->size = tlb_size;
lu->err = ERR_HIT;
lu->idx = i;
hit = 1;
goto done;
}
}
done:
D(qemu_log("MMU vaddr=%x rw=%d tlb_wr=%d tlb_ex=%d hit=%d\n",
vaddr, rw, tlb_wr, tlb_ex, hit));
return hit;
}
/* Writes/reads to the MMU's special regs end up here. */
uint32_t mmu_read(CPUState *env, uint32_t rn)
{
unsigned int i;
uint32_t r;
if (env->mmu.c_mmu < 2 || !env->mmu.c_mmu_tlb_access) {
qemu_log("MMU access on MMU-less system\n");
return 0;
}
switch (rn) {
/* Reads to HI/LO trig reads from the mmu rams. */
case MMU_R_TLBLO:
case MMU_R_TLBHI:
if (!(env->mmu.c_mmu_tlb_access & 1)) {
qemu_log("Invalid access to MMU reg %d\n", rn);
return 0;
}
i = env->mmu.regs[MMU_R_TLBX] & 0xff;
r = env->mmu.rams[rn & 1][i];
if (rn == MMU_R_TLBHI)
env->mmu.regs[MMU_R_PID] = env->mmu.tids[i];
break;
case MMU_R_PID:
case MMU_R_ZPR:
if (!(env->mmu.c_mmu_tlb_access & 1)) {
qemu_log("Invalid access to MMU reg %d\n", rn);
return 0;
}
r = env->mmu.regs[rn];
break;
default:
r = env->mmu.regs[rn];
break;
}
D(qemu_log("%s rn=%d=%x\n", __func__, rn, r));
return r;
}
void mmu_write(CPUState *env, uint32_t rn, uint32_t v)
{
unsigned int i;
D(qemu_log("%s rn=%d=%x old=%x\n", __func__, rn, v, env->mmu.regs[rn]));
if (env->mmu.c_mmu < 2 || !env->mmu.c_mmu_tlb_access) {
qemu_log("MMU access on MMU-less system\n");
return;
}
switch (rn) {
/* Writes to HI/LO trig writes to the mmu rams. */
case MMU_R_TLBLO:
case MMU_R_TLBHI:
i = env->mmu.regs[MMU_R_TLBX] & 0xff;
if (rn == MMU_R_TLBHI) {
if (i < 3 && !(v & TLB_VALID) && qemu_loglevel_mask(~0))
qemu_log("invalidating index %x at pc=%x\n",
i, env->sregs[SR_PC]);
env->mmu.tids[i] = env->mmu.regs[MMU_R_PID] & 0xff;
mmu_flush_idx(env, i);
}
env->mmu.rams[rn & 1][i] = v;
D(qemu_log("%s ram[%d][%d]=%x\n", __func__, rn & 1, i, v));
break;
case MMU_R_ZPR:
if (env->mmu.c_mmu_tlb_access <= 1) {
qemu_log("Invalid access to MMU reg %d\n", rn);
return;
}
/* Changes to the zone protection reg flush the QEMU TLB.
Fortunately, these are very uncommon. */
if (v != env->mmu.regs[rn]) {
tlb_flush(env, 1);
}
env->mmu.regs[rn] = v;
break;
case MMU_R_PID:
if (env->mmu.c_mmu_tlb_access <= 1) {
qemu_log("Invalid access to MMU reg %d\n", rn);
return;
}
if (v != env->mmu.regs[rn]) {
mmu_change_pid(env, v);
env->mmu.regs[rn] = v;
}
break;
case MMU_R_TLBSX:
{
struct microblaze_mmu_lookup lu;
int hit;
if (env->mmu.c_mmu_tlb_access <= 1) {
qemu_log("Invalid access to MMU reg %d\n", rn);
return;
}
hit = mmu_translate(&env->mmu, &lu,
v & TLB_EPN_MASK, 0, cpu_mmu_index(env));
if (hit) {
env->mmu.regs[MMU_R_TLBX] = lu.idx;
} else
env->mmu.regs[MMU_R_TLBX] |= 0x80000000;
break;
}
default:
env->mmu.regs[rn] = v;
break;
}
}
void mmu_init(struct microblaze_mmu *mmu)
{
int i;
for (i = 0; i < ARRAY_SIZE(mmu->regs); i++) {
mmu->regs[i] = 0;
}
}
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