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qemu-patch-raspberry4/target/ppc/mmu-hash32.c
David Gibson 36778660d7 target/ppc: Eliminate htab_base and htab_mask variables 
CPUPPCState includes fields htab_base and htab_mask which store the base
address (GPA) and size (as a mask) of the guest's hashed page table (HPT).
These are set when the SDR1 register is updated.

Keeping these in sync with the SDR1 is actually a little bit fiddly, and
probably not useful for performance, since keeping them expands the size of
CPUPPCState.  It also makes some upcoming changes harder to implement.

This patch removes these fields, in favour of calculating them directly
from the SDR1 contents when necessary.

This does make a change to the behaviour of attempting to write a bad value
(invalid HPT size) to the SDR1 with an mtspr instruction.  Previously, the
bad value would be stored in SDR1 and could be retrieved with a later
mfspr, but the HPT size as used by the softmmu would be, clamped to the
allowed values.  Now, writing a bad value is treated as a no-op.  An error
message is printed in both new and old versions.

I'm not sure which behaviour, if either, matches real hardware.  I don't
think it matters that much, since it's pretty clear that if an OS writes
a bad value to SDR1, it's not going to boot.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru>
2017-03-01 11:23:39 +11:00

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/*
* PowerPC MMU, TLB and BAT emulation helpers for QEMU.
*
* Copyright (c) 2003-2007 Jocelyn Mayer
* Copyright (c) 2013 David Gibson, IBM Corporation
*
* 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 "qemu/osdep.h"
#include "cpu.h"
#include "exec/exec-all.h"
#include "exec/helper-proto.h"
#include "sysemu/kvm.h"
#include "kvm_ppc.h"
#include "mmu-hash32.h"
#include "exec/log.h"
//#define DEBUG_BAT
#ifdef DEBUG_BATS
# define LOG_BATS(...) qemu_log_mask(CPU_LOG_MMU, __VA_ARGS__)
#else
# define LOG_BATS(...) do { } while (0)
#endif
struct mmu_ctx_hash32 {
hwaddr raddr; /* Real address */
int prot; /* Protection bits */
int key; /* Access key */
};
static int ppc_hash32_pp_prot(int key, int pp, int nx)
{
int prot;
if (key == 0) {
switch (pp) {
case 0x0:
case 0x1:
case 0x2:
prot = PAGE_READ | PAGE_WRITE;
break;
case 0x3:
prot = PAGE_READ;
break;
default:
abort();
}
} else {
switch (pp) {
case 0x0:
prot = 0;
break;
case 0x1:
case 0x3:
prot = PAGE_READ;
break;
case 0x2:
prot = PAGE_READ | PAGE_WRITE;
break;
default:
abort();
}
}
if (nx == 0) {
prot |= PAGE_EXEC;
}
return prot;
}
static int ppc_hash32_pte_prot(PowerPCCPU *cpu,
target_ulong sr, ppc_hash_pte32_t pte)
{
CPUPPCState *env = &cpu->env;
unsigned pp, key;
key = !!(msr_pr ? (sr & SR32_KP) : (sr & SR32_KS));
pp = pte.pte1 & HPTE32_R_PP;
return ppc_hash32_pp_prot(key, pp, !!(sr & SR32_NX));
}
static target_ulong hash32_bat_size(PowerPCCPU *cpu,
target_ulong batu, target_ulong batl)
{
CPUPPCState *env = &cpu->env;
if ((msr_pr && !(batu & BATU32_VP))
|| (!msr_pr && !(batu & BATU32_VS))) {
return 0;
}
return BATU32_BEPI & ~((batu & BATU32_BL) << 15);
}
static int hash32_bat_prot(PowerPCCPU *cpu,
target_ulong batu, target_ulong batl)
{
int pp, prot;
prot = 0;
pp = batl & BATL32_PP;
if (pp != 0) {
prot = PAGE_READ | PAGE_EXEC;
if (pp == 0x2) {
prot |= PAGE_WRITE;
}
}
return prot;
}
static target_ulong hash32_bat_601_size(PowerPCCPU *cpu,
target_ulong batu, target_ulong batl)
{
if (!(batl & BATL32_601_V)) {
return 0;
}
return BATU32_BEPI & ~((batl & BATL32_601_BL) << 17);
}
static int hash32_bat_601_prot(PowerPCCPU *cpu,
target_ulong batu, target_ulong batl)
{
CPUPPCState *env = &cpu->env;
int key, pp;
pp = batu & BATU32_601_PP;
if (msr_pr == 0) {
key = !!(batu & BATU32_601_KS);
} else {
key = !!(batu & BATU32_601_KP);
}
return ppc_hash32_pp_prot(key, pp, 0);
}
static hwaddr ppc_hash32_bat_lookup(PowerPCCPU *cpu, target_ulong ea, int rwx,
int *prot)
{
CPUPPCState *env = &cpu->env;
target_ulong *BATlt, *BATut;
int i;
LOG_BATS("%s: %cBAT v " TARGET_FMT_lx "\n", __func__,
rwx == 2 ? 'I' : 'D', ea);
if (rwx == 2) {
BATlt = env->IBAT[1];
BATut = env->IBAT[0];
} else {
BATlt = env->DBAT[1];
BATut = env->DBAT[0];
}
for (i = 0; i < env->nb_BATs; i++) {
target_ulong batu = BATut[i];
target_ulong batl = BATlt[i];
target_ulong mask;
if (unlikely(env->mmu_model == POWERPC_MMU_601)) {
mask = hash32_bat_601_size(cpu, batu, batl);
} else {
mask = hash32_bat_size(cpu, batu, batl);
}
LOG_BATS("%s: %cBAT%d v " TARGET_FMT_lx " BATu " TARGET_FMT_lx
" BATl " TARGET_FMT_lx "\n", __func__,
type == ACCESS_CODE ? 'I' : 'D', i, ea, batu, batl);
if (mask && ((ea & mask) == (batu & BATU32_BEPI))) {
hwaddr raddr = (batl & mask) | (ea & ~mask);
if (unlikely(env->mmu_model == POWERPC_MMU_601)) {
*prot = hash32_bat_601_prot(cpu, batu, batl);
} else {
*prot = hash32_bat_prot(cpu, batu, batl);
}
return raddr & TARGET_PAGE_MASK;
}
}
/* No hit */
#if defined(DEBUG_BATS)
if (qemu_log_enabled()) {
LOG_BATS("no BAT match for " TARGET_FMT_lx ":\n", ea);
for (i = 0; i < 4; i++) {
BATu = &BATut[i];
BATl = &BATlt[i];
BEPIu = *BATu & BATU32_BEPIU;
BEPIl = *BATu & BATU32_BEPIL;
bl = (*BATu & 0x00001FFC) << 15;
LOG_BATS("%s: %cBAT%d v " TARGET_FMT_lx " BATu " TARGET_FMT_lx
" BATl " TARGET_FMT_lx "\n\t" TARGET_FMT_lx " "
TARGET_FMT_lx " " TARGET_FMT_lx "\n",
__func__, type == ACCESS_CODE ? 'I' : 'D', i, ea,
*BATu, *BATl, BEPIu, BEPIl, bl);
}
}
#endif
return -1;
}
static int ppc_hash32_direct_store(PowerPCCPU *cpu, target_ulong sr,
target_ulong eaddr, int rwx,
hwaddr *raddr, int *prot)
{
CPUState *cs = CPU(cpu);
CPUPPCState *env = &cpu->env;
int key = !!(msr_pr ? (sr & SR32_KP) : (sr & SR32_KS));
qemu_log_mask(CPU_LOG_MMU, "direct store...\n");
if ((sr & 0x1FF00000) >> 20 == 0x07f) {
/* Memory-forced I/O controller interface access */
/* If T=1 and BUID=x'07F', the 601 performs a memory access
* to SR[28-31] LA[4-31], bypassing all protection mechanisms.
*/
*raddr = ((sr & 0xF) << 28) | (eaddr & 0x0FFFFFFF);
*prot = PAGE_READ | PAGE_WRITE | PAGE_EXEC;
return 0;
}
if (rwx == 2) {
/* No code fetch is allowed in direct-store areas */
cs->exception_index = POWERPC_EXCP_ISI;
env->error_code = 0x10000000;
return 1;
}
switch (env->access_type) {
case ACCESS_INT:
/* Integer load/store : only access allowed */
break;
case ACCESS_FLOAT:
/* Floating point load/store */
cs->exception_index = POWERPC_EXCP_ALIGN;
env->error_code = POWERPC_EXCP_ALIGN_FP;
env->spr[SPR_DAR] = eaddr;
return 1;
case ACCESS_RES:
/* lwarx, ldarx or srwcx. */
env->error_code = 0;
env->spr[SPR_DAR] = eaddr;
if (rwx == 1) {
env->spr[SPR_DSISR] = 0x06000000;
} else {
env->spr[SPR_DSISR] = 0x04000000;
}
return 1;
case ACCESS_CACHE:
/* dcba, dcbt, dcbtst, dcbf, dcbi, dcbst, dcbz, or icbi */
/* Should make the instruction do no-op.
* As it already do no-op, it's quite easy :-)
*/
*raddr = eaddr;
return 0;
case ACCESS_EXT:
/* eciwx or ecowx */
cs->exception_index = POWERPC_EXCP_DSI;
env->error_code = 0;
env->spr[SPR_DAR] = eaddr;
if (rwx == 1) {
env->spr[SPR_DSISR] = 0x06100000;
} else {
env->spr[SPR_DSISR] = 0x04100000;
}
return 1;
default:
cpu_abort(cs, "ERROR: instruction should not need "
"address translation\n");
}
if ((rwx == 1 || key != 1) && (rwx == 0 || key != 0)) {
*raddr = eaddr;
return 0;
} else {
cs->exception_index = POWERPC_EXCP_DSI;
env->error_code = 0;
env->spr[SPR_DAR] = eaddr;
if (rwx == 1) {
env->spr[SPR_DSISR] = 0x0a000000;
} else {
env->spr[SPR_DSISR] = 0x08000000;
}
return 1;
}
}
hwaddr get_pteg_offset32(PowerPCCPU *cpu, hwaddr hash)
{
target_ulong mask = ppc_hash32_hpt_mask(cpu);
return (hash * HASH_PTEG_SIZE_32) & mask;
}
static hwaddr ppc_hash32_pteg_search(PowerPCCPU *cpu, hwaddr pteg_off,
bool secondary, target_ulong ptem,
ppc_hash_pte32_t *pte)
{
hwaddr pte_offset = pteg_off;
target_ulong pte0, pte1;
int i;
for (i = 0; i < HPTES_PER_GROUP; i++) {
pte0 = ppc_hash32_load_hpte0(cpu, pte_offset);
pte1 = ppc_hash32_load_hpte1(cpu, pte_offset);
if ((pte0 & HPTE32_V_VALID)
&& (secondary == !!(pte0 & HPTE32_V_SECONDARY))
&& HPTE32_V_COMPARE(pte0, ptem)) {
pte->pte0 = pte0;
pte->pte1 = pte1;
return pte_offset;
}
pte_offset += HASH_PTE_SIZE_32;
}
return -1;
}
static hwaddr ppc_hash32_htab_lookup(PowerPCCPU *cpu,
target_ulong sr, target_ulong eaddr,
ppc_hash_pte32_t *pte)
{
hwaddr pteg_off, pte_offset;
hwaddr hash;
uint32_t vsid, pgidx, ptem;
vsid = sr & SR32_VSID;
pgidx = (eaddr & ~SEGMENT_MASK_256M) >> TARGET_PAGE_BITS;
hash = vsid ^ pgidx;
ptem = (vsid << 7) | (pgidx >> 10);
/* Page address translation */
qemu_log_mask(CPU_LOG_MMU, "htab_base " TARGET_FMT_plx
" htab_mask " TARGET_FMT_plx
" hash " TARGET_FMT_plx "\n",
ppc_hash32_hpt_base(cpu), ppc_hash32_hpt_mask(cpu), hash);
/* Primary PTEG lookup */
qemu_log_mask(CPU_LOG_MMU, "0 htab=" TARGET_FMT_plx "/" TARGET_FMT_plx
" vsid=%" PRIx32 " ptem=%" PRIx32
" hash=" TARGET_FMT_plx "\n",
ppc_hash32_hpt_base(cpu), ppc_hash32_hpt_mask(cpu),
vsid, ptem, hash);
pteg_off = get_pteg_offset32(cpu, hash);
pte_offset = ppc_hash32_pteg_search(cpu, pteg_off, 0, ptem, pte);
if (pte_offset == -1) {
/* Secondary PTEG lookup */
qemu_log_mask(CPU_LOG_MMU, "1 htab=" TARGET_FMT_plx "/" TARGET_FMT_plx
" vsid=%" PRIx32 " api=%" PRIx32
" hash=" TARGET_FMT_plx "\n", ppc_hash32_hpt_base(cpu),
ppc_hash32_hpt_mask(cpu), vsid, ptem, ~hash);
pteg_off = get_pteg_offset32(cpu, ~hash);
pte_offset = ppc_hash32_pteg_search(cpu, pteg_off, 1, ptem, pte);
}
return pte_offset;
}
static hwaddr ppc_hash32_pte_raddr(target_ulong sr, ppc_hash_pte32_t pte,
target_ulong eaddr)
{
hwaddr rpn = pte.pte1 & HPTE32_R_RPN;
hwaddr mask = ~TARGET_PAGE_MASK;
return (rpn & ~mask) | (eaddr & mask);
}
int ppc_hash32_handle_mmu_fault(PowerPCCPU *cpu, vaddr eaddr, int rwx,
int mmu_idx)
{
CPUState *cs = CPU(cpu);
CPUPPCState *env = &cpu->env;
target_ulong sr;
hwaddr pte_offset;
ppc_hash_pte32_t pte;
int prot;
uint32_t new_pte1;
const int need_prot[] = {PAGE_READ, PAGE_WRITE, PAGE_EXEC};
hwaddr raddr;
assert((rwx == 0) || (rwx == 1) || (rwx == 2));
/* 1. Handle real mode accesses */
if (((rwx == 2) && (msr_ir == 0)) || ((rwx != 2) && (msr_dr == 0))) {
/* Translation is off */
raddr = eaddr;
tlb_set_page(cs, eaddr & TARGET_PAGE_MASK, raddr & TARGET_PAGE_MASK,
PAGE_READ | PAGE_WRITE | PAGE_EXEC, mmu_idx,
TARGET_PAGE_SIZE);
return 0;
}
/* 2. Check Block Address Translation entries (BATs) */
if (env->nb_BATs != 0) {
raddr = ppc_hash32_bat_lookup(cpu, eaddr, rwx, &prot);
if (raddr != -1) {
if (need_prot[rwx] & ~prot) {
if (rwx == 2) {
cs->exception_index = POWERPC_EXCP_ISI;
env->error_code = 0x08000000;
} else {
cs->exception_index = POWERPC_EXCP_DSI;
env->error_code = 0;
env->spr[SPR_DAR] = eaddr;
if (rwx == 1) {
env->spr[SPR_DSISR] = 0x0a000000;
} else {
env->spr[SPR_DSISR] = 0x08000000;
}
}
return 1;
}
tlb_set_page(cs, eaddr & TARGET_PAGE_MASK,
raddr & TARGET_PAGE_MASK, prot, mmu_idx,
TARGET_PAGE_SIZE);
return 0;
}
}
/* 3. Look up the Segment Register */
sr = env->sr[eaddr >> 28];
/* 4. Handle direct store segments */
if (sr & SR32_T) {
if (ppc_hash32_direct_store(cpu, sr, eaddr, rwx,
&raddr, &prot) == 0) {
tlb_set_page(cs, eaddr & TARGET_PAGE_MASK,
raddr & TARGET_PAGE_MASK, prot, mmu_idx,
TARGET_PAGE_SIZE);
return 0;
} else {
return 1;
}
}
/* 5. Check for segment level no-execute violation */
if ((rwx == 2) && (sr & SR32_NX)) {
cs->exception_index = POWERPC_EXCP_ISI;
env->error_code = 0x10000000;
return 1;
}
/* 6. Locate the PTE in the hash table */
pte_offset = ppc_hash32_htab_lookup(cpu, sr, eaddr, &pte);
if (pte_offset == -1) {
if (rwx == 2) {
cs->exception_index = POWERPC_EXCP_ISI;
env->error_code = 0x40000000;
} else {
cs->exception_index = POWERPC_EXCP_DSI;
env->error_code = 0;
env->spr[SPR_DAR] = eaddr;
if (rwx == 1) {
env->spr[SPR_DSISR] = 0x42000000;
} else {
env->spr[SPR_DSISR] = 0x40000000;
}
}
return 1;
}
qemu_log_mask(CPU_LOG_MMU,
"found PTE at offset %08" HWADDR_PRIx "\n", pte_offset);
/* 7. Check access permissions */
prot = ppc_hash32_pte_prot(cpu, sr, pte);
if (need_prot[rwx] & ~prot) {
/* Access right violation */
qemu_log_mask(CPU_LOG_MMU, "PTE access rejected\n");
if (rwx == 2) {
cs->exception_index = POWERPC_EXCP_ISI;
env->error_code = 0x08000000;
} else {
cs->exception_index = POWERPC_EXCP_DSI;
env->error_code = 0;
env->spr[SPR_DAR] = eaddr;
if (rwx == 1) {
env->spr[SPR_DSISR] = 0x0a000000;
} else {
env->spr[SPR_DSISR] = 0x08000000;
}
}
return 1;
}
qemu_log_mask(CPU_LOG_MMU, "PTE access granted !\n");
/* 8. Update PTE referenced and changed bits if necessary */
new_pte1 = pte.pte1 | HPTE32_R_R; /* set referenced bit */
if (rwx == 1) {
new_pte1 |= HPTE32_R_C; /* set changed (dirty) bit */
} else {
/* Treat the page as read-only for now, so that a later write
* will pass through this function again to set the C bit */
prot &= ~PAGE_WRITE;
}
if (new_pte1 != pte.pte1) {
ppc_hash32_store_hpte1(cpu, pte_offset, new_pte1);
}
/* 9. Determine the real address from the PTE */
raddr = ppc_hash32_pte_raddr(sr, pte, eaddr);
tlb_set_page(cs, eaddr & TARGET_PAGE_MASK, raddr & TARGET_PAGE_MASK,
prot, mmu_idx, TARGET_PAGE_SIZE);
return 0;
}
hwaddr ppc_hash32_get_phys_page_debug(PowerPCCPU *cpu, target_ulong eaddr)
{
CPUPPCState *env = &cpu->env;
target_ulong sr;
hwaddr pte_offset;
ppc_hash_pte32_t pte;
int prot;
if (msr_dr == 0) {
/* Translation is off */
return eaddr;
}
if (env->nb_BATs != 0) {
hwaddr raddr = ppc_hash32_bat_lookup(cpu, eaddr, 0, &prot);
if (raddr != -1) {
return raddr;
}
}
sr = env->sr[eaddr >> 28];
if (sr & SR32_T) {
/* FIXME: Add suitable debug support for Direct Store segments */
return -1;
}
pte_offset = ppc_hash32_htab_lookup(cpu, sr, eaddr, &pte);
if (pte_offset == -1) {
return -1;
}
return ppc_hash32_pte_raddr(sr, pte, eaddr) & TARGET_PAGE_MASK;
}
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