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target/mips: Implement hardware page table walker for MIPS32 

Implement hardware page table walker. This implementation is
limiter only to MIPS32.

Reviewed-by: Aleksandar Markovic <amarkovic@wavecomp.com>
Signed-off-by: Yongbok Kim <yongbok.kim@mips.com>
Signed-off-by: Aleksandar Markovic <amarkovic@wavecomp.com>
This commit is contained in:
Yongbok Kim 2018-10-09 18:54:46 +02:00 committed by Aleksandar Markovic
parent 6301079557
commit 074cfcb4da
3 changed files with 370 additions and 3 deletions
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365
target/mips/helper.c
View File

@ -537,6 +537,342 @@ hwaddr mips_cpu_get_phys_page_debug(CPUState *cs, vaddr addr)
}
#endif
#if !defined(CONFIG_USER_ONLY)
#if !defined(TARGET_MIPS64)
/*
* Perform hardware page table walk
*
* Memory accesses are performed using the KERNEL privilege level.
* Synchronous exceptions detected on memory accesses cause a silent exit
* from page table walking, resulting in a TLB or XTLB Refill exception.
*
* Implementations are not required to support page table walk memory
* accesses from mapped memory regions. When an unsupported access is
* attempted, a silent exit is taken, resulting in a TLB or XTLB Refill
* exception.
*
* Note that if an exception is caused by AddressTranslation or LoadMemory
* functions, the exception is not taken, a silent exit is taken,
* resulting in a TLB or XTLB Refill exception.
*/
static bool get_pte(CPUMIPSState *env, uint64_t vaddr, int entry_size,
uint64_t *pte)
{
if ((vaddr & ((entry_size >> 3) - 1)) != 0) {
return false;
}
if (entry_size == 64) {
*pte = cpu_ldq_code(env, vaddr);
} else {
*pte = cpu_ldl_code(env, vaddr);
}
return true;
}
static uint64_t get_tlb_entry_layout(CPUMIPSState *env, uint64_t entry,
int entry_size, int ptei)
{
uint64_t result = entry;
uint64_t rixi;
if (ptei > entry_size) {
ptei -= 32;
}
result >>= (ptei - 2);
rixi = result & 3;
result >>= 2;
result |= rixi << CP0EnLo_XI;
return result;
}
static int walk_directory(CPUMIPSState *env, uint64_t *vaddr,
int directory_index, bool *huge_page, bool *hgpg_directory_hit,
uint64_t *pw_entrylo0, uint64_t *pw_entrylo1)
{
int dph = (env->CP0_PWCtl >> CP0PC_DPH) & 0x1;
int psn = (env->CP0_PWCtl >> CP0PC_PSN) & 0x3F;
int hugepg = (env->CP0_PWCtl >> CP0PC_HUGEPG) & 0x1;
int pf_ptew = (env->CP0_PWField >> CP0PF_PTEW) & 0x3F;
int ptew = (env->CP0_PWSize >> CP0PS_PTEW) & 0x3F;
int native_shift = (((env->CP0_PWSize >> CP0PS_PS) & 1) == 0) ? 2 : 3;
int directory_shift = (ptew > 1) ? -1 :
(hugepg && (ptew == 1)) ? native_shift + 1 : native_shift;
int leaf_shift = (ptew > 1) ? -1 :
(ptew == 1) ? native_shift + 1 : native_shift;
uint32_t direntry_size = 1 << (directory_shift + 3);
uint32_t leafentry_size = 1 << (leaf_shift + 3);
uint64_t entry;
uint64_t paddr;
int prot;
uint64_t lsb = 0;
uint64_t w = 0;
if (get_physical_address(env, &paddr, &prot, *vaddr, MMU_DATA_LOAD,
ACCESS_INT, cpu_mmu_index(env, false)) !=
TLBRET_MATCH) {
/* wrong base address */
return 0;
}
if (!get_pte(env, *vaddr, direntry_size, &entry)) {
return 0;
}
if ((entry & (1 << psn)) && hugepg) {
*huge_page = true;
*hgpg_directory_hit = true;
entry = get_tlb_entry_layout(env, entry, leafentry_size, pf_ptew);
w = directory_index - 1;
if (directory_index & 0x1) {
/* Generate adjacent page from same PTE for odd TLB page */
lsb = (1 << w) >> 6;
*pw_entrylo0 = entry & ~lsb; /* even page */
*pw_entrylo1 = entry | lsb; /* odd page */
} else if (dph) {
int oddpagebit = 1 << leaf_shift;
uint64_t vaddr2 = *vaddr ^ oddpagebit;
if (*vaddr & oddpagebit) {
*pw_entrylo1 = entry;
} else {
*pw_entrylo0 = entry;
}
if (get_physical_address(env, &paddr, &prot, vaddr2, MMU_DATA_LOAD,
ACCESS_INT, cpu_mmu_index(env, false)) !=
TLBRET_MATCH) {
return 0;
}
if (!get_pte(env, vaddr2, leafentry_size, &entry)) {
return 0;
}
entry = get_tlb_entry_layout(env, entry, leafentry_size, pf_ptew);
if (*vaddr & oddpagebit) {
*pw_entrylo0 = entry;
} else {
*pw_entrylo1 = entry;
}
} else {
return 0;
}
return 1;
} else {
*vaddr = entry;
return 2;
}
}
static bool page_table_walk_refill(CPUMIPSState *env, vaddr address, int rw,
int mmu_idx)
{
int gdw = (env->CP0_PWSize >> CP0PS_GDW) & 0x3F;
int udw = (env->CP0_PWSize >> CP0PS_UDW) & 0x3F;
int mdw = (env->CP0_PWSize >> CP0PS_MDW) & 0x3F;
int ptw = (env->CP0_PWSize >> CP0PS_PTW) & 0x3F;
int ptew = (env->CP0_PWSize >> CP0PS_PTEW) & 0x3F;
/* Initial values */
bool huge_page = false;
bool hgpg_bdhit = false;
bool hgpg_gdhit = false;
bool hgpg_udhit = false;
bool hgpg_mdhit = false;
int32_t pw_pagemask = 0;
target_ulong pw_entryhi = 0;
uint64_t pw_entrylo0 = 0;
uint64_t pw_entrylo1 = 0;
/* Native pointer size */
/*For the 32-bit architectures, this bit is fixed to 0.*/
int native_shift = (((env->CP0_PWSize >> CP0PS_PS) & 1) == 0) ? 2 : 3;
/* Indices from PWField */
int pf_gdw = (env->CP0_PWField >> CP0PF_GDW) & 0x3F;
int pf_udw = (env->CP0_PWField >> CP0PF_UDW) & 0x3F;
int pf_mdw = (env->CP0_PWField >> CP0PF_MDW) & 0x3F;
int pf_ptw = (env->CP0_PWField >> CP0PF_PTW) & 0x3F;
int pf_ptew = (env->CP0_PWField >> CP0PF_PTEW) & 0x3F;
/* Indices computed from faulting address */
int gindex = (address >> pf_gdw) & ((1 << gdw) - 1);
int uindex = (address >> pf_udw) & ((1 << udw) - 1);
int mindex = (address >> pf_mdw) & ((1 << mdw) - 1);
int ptindex = (address >> pf_ptw) & ((1 << ptw) - 1);
/* Other HTW configs */
int hugepg = (env->CP0_PWCtl >> CP0PC_HUGEPG) & 0x1;
/* HTW Shift values (depend on entry size) */
int directory_shift = (ptew > 1) ? -1 :
(hugepg && (ptew == 1)) ? native_shift + 1 : native_shift;
int leaf_shift = (ptew > 1) ? -1 :
(ptew == 1) ? native_shift + 1 : native_shift;
/* Offsets into tables */
int goffset = gindex << directory_shift;
int uoffset = uindex << directory_shift;
int moffset = mindex << directory_shift;
int ptoffset0 = (ptindex >> 1) << (leaf_shift + 1);
int ptoffset1 = ptoffset0 | (1 << (leaf_shift));
uint32_t leafentry_size = 1 << (leaf_shift + 3);
/* Starting address - Page Table Base */
uint64_t vaddr = env->CP0_PWBase;
uint64_t dir_entry;
uint64_t paddr;
int prot;
int m;
if (!(env->CP0_Config3 & (1 << CP0C3_PW))) {
/* walker is unimplemented */
return false;
}
if (!(env->CP0_PWCtl & (1 << CP0PC_PWEN))) {
/* walker is disabled */
return false;
}
if (!(gdw > 0 || udw > 0 || mdw > 0)) {
/* no structure to walk */
return false;
}
if ((directory_shift == -1) || (leaf_shift == -1)) {
return false;
}
/* Global Directory */
if (gdw > 0) {
vaddr |= goffset;
switch (walk_directory(env, &vaddr, pf_gdw, &huge_page, &hgpg_gdhit,
&pw_entrylo0, &pw_entrylo1))
{
case 0:
return false;
case 1:
goto refill;
case 2:
default:
break;
}
}
/* Upper directory */
if (udw > 0) {
vaddr |= uoffset;
switch (walk_directory(env, &vaddr, pf_udw, &huge_page, &hgpg_udhit,
&pw_entrylo0, &pw_entrylo1))
{
case 0:
return false;
case 1:
goto refill;
case 2:
default:
break;
}
}
/* Middle directory */
if (mdw > 0) {
vaddr |= moffset;
switch (walk_directory(env, &vaddr, pf_mdw, &huge_page, &hgpg_mdhit,
&pw_entrylo0, &pw_entrylo1))
{
case 0:
return false;
case 1:
goto refill;
case 2:
default:
break;
}
}
/* Leaf Level Page Table - First half of PTE pair */
vaddr |= ptoffset0;
if (get_physical_address(env, &paddr, &prot, vaddr, MMU_DATA_LOAD,
ACCESS_INT, cpu_mmu_index(env, false)) !=
TLBRET_MATCH) {
return false;
}
if (!get_pte(env, vaddr, leafentry_size, &dir_entry)) {
return false;
}
dir_entry = get_tlb_entry_layout(env, dir_entry, leafentry_size, pf_ptew);
pw_entrylo0 = dir_entry;
/* Leaf Level Page Table - Second half of PTE pair */
vaddr |= ptoffset1;
if (get_physical_address(env, &paddr, &prot, vaddr, MMU_DATA_LOAD,
ACCESS_INT, cpu_mmu_index(env, false)) !=
TLBRET_MATCH) {
return false;
}
if (!get_pte(env, vaddr, leafentry_size, &dir_entry)) {
return false;
}
dir_entry = get_tlb_entry_layout(env, dir_entry, leafentry_size, pf_ptew);
pw_entrylo1 = dir_entry;
refill:
m = (1 << pf_ptw) - 1;
if (huge_page) {
switch (hgpg_bdhit << 3 | hgpg_gdhit << 2 | hgpg_udhit << 1 |
hgpg_mdhit)
{
case 4:
m = (1 << pf_gdw) - 1;
if (pf_gdw & 1) {
m >>= 1;
}
break;
case 2:
m = (1 << pf_udw) - 1;
if (pf_udw & 1) {
m >>= 1;
}
break;
case 1:
m = (1 << pf_mdw) - 1;
if (pf_mdw & 1) {
m >>= 1;
}
break;
}
}
pw_pagemask = m >> 12;
update_pagemask(env, pw_pagemask << 13, &pw_pagemask);
pw_entryhi = (address & ~0x1fff) | (env->CP0_EntryHi & 0xFF);
{
target_ulong tmp_entryhi = env->CP0_EntryHi;
int32_t tmp_pagemask = env->CP0_PageMask;
uint64_t tmp_entrylo0 = env->CP0_EntryLo0;
uint64_t tmp_entrylo1 = env->CP0_EntryLo1;
env->CP0_EntryHi = pw_entryhi;
env->CP0_PageMask = pw_pagemask;
env->CP0_EntryLo0 = pw_entrylo0;
env->CP0_EntryLo1 = pw_entrylo1;
/*
* The hardware page walker inserts a page into the TLB in a manner
* identical to a TLBWR instruction as executed by the software refill
* handler.
*/
r4k_helper_tlbwr(env);
env->CP0_EntryHi = tmp_entryhi;
env->CP0_PageMask = tmp_pagemask;
env->CP0_EntryLo0 = tmp_entrylo0;
env->CP0_EntryLo1 = tmp_entrylo1;
}
return true;
}
#endif
#endif
int mips_cpu_handle_mmu_fault(CPUState *cs, vaddr address, int size, int rw,
int mmu_idx)
{
@ -558,8 +894,7 @@ int mips_cpu_handle_mmu_fault(CPUState *cs, vaddr address, int size, int rw,
/* data access */
#if !defined(CONFIG_USER_ONLY)
/* XXX: put correct access by using cpu_restore_state()
correctly */
/* XXX: put correct access by using cpu_restore_state() correctly */
access_type = ACCESS_INT;
ret = get_physical_address(env, &physical, &prot,
address, rw, access_type, mmu_idx);
@ -583,6 +918,32 @@ int mips_cpu_handle_mmu_fault(CPUState *cs, vaddr address, int size, int rw,
} else if (ret < 0)
#endif
{
#if !defined(CONFIG_USER_ONLY)
#if !defined(TARGET_MIPS64)
if ((ret == TLBRET_NOMATCH) && (env->tlb->nb_tlb > 1)) {
/*
* Memory reads during hardware page table walking are performed
* as if they were kernel-mode load instructions.
*/
int mode = (env->hflags & MIPS_HFLAG_KSU);
bool ret_walker;
env->hflags &= ~MIPS_HFLAG_KSU;
ret_walker = page_table_walk_refill(env, address, rw, mmu_idx);
env->hflags |= mode;
if (ret_walker) {
ret = get_physical_address(env, &physical, &prot,
address, rw, access_type, mmu_idx);
if (ret == TLBRET_MATCH) {
tlb_set_page(cs, address & TARGET_PAGE_MASK,
physical & TARGET_PAGE_MASK, prot | PAGE_EXEC,
mmu_idx, TARGET_PAGE_SIZE);
ret = 0;
return ret;
}
}
}
#endif
#endif
raise_mmu_exception(env, address, rw, ret);
ret = 1;
}

1
target/mips/internal.h
View File

@ -211,6 +211,7 @@ uint64_t float_class_d(uint64_t arg, float_status *fst);
extern unsigned int ieee_rm[];
int ieee_ex_to_mips(int xcpt);
void update_pagemask(CPUMIPSState *env, target_ulong arg1, int32_t *pagemask);
static inline void restore_rounding_mode(CPUMIPSState *env)
{

7
target/mips/op_helper.c
View File

@ -1400,7 +1400,7 @@ void helper_mtc0_context(CPUMIPSState *env, target_ulong arg1)
env->CP0_Context = (env->CP0_Context & 0x007FFFFF) | (arg1 & ~0x007FFFFF);
}
void helper_mtc0_pagemask(CPUMIPSState *env, target_ulong arg1)
void update_pagemask(CPUMIPSState *env, target_ulong arg1, int32_t *pagemask)
{
uint64_t mask = arg1 >> (TARGET_PAGE_BITS + 1);
if (!(env->insn_flags & ISA_MIPS32R6) || (arg1 == ~0) ||
@ -1411,6 +1411,11 @@ void helper_mtc0_pagemask(CPUMIPSState *env, target_ulong arg1)
}
}
void helper_mtc0_pagemask(CPUMIPSState *env, target_ulong arg1)
{
update_pagemask(env, arg1, &env->CP0_PageMask);
}
void helper_mtc0_pagegrain(CPUMIPSState *env, target_ulong arg1)
{
/* SmartMIPS not implemented */