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/*
* Copyright (c) 2003-2004 Jakub Jermar
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* - Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* - 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.
* - The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
*/
/** @addtogroup mips32mm
* @{
*/
/** @file
*/
#include <arch/mm/tlb.h>
#include <mm/asid.h>
#include <mm/tlb.h>
#include <mm/page.h>
#include <mm/as.h>
#include <arch/cp0.h>
#include <panic.h>
#include <arch.h>
#include <synch/mutex.h>
#include <print.h>
#include <debug.h>
#include <align.h>
#include <interrupt.h>
#include <symtab.h>
static void tlb_refill_fail(istate_t *);
static void tlb_invalid_fail(istate_t *);
static void tlb_modified_fail(istate_t *);
static pte_t *find_mapping_and_check(uintptr_t, int, istate_t *, int *);
/** Initialize TLB.
*
* Invalidate all entries and mark wired entries.
*/
void tlb_arch_init(void)
{
int i;
cp0_pagemask_write(TLB_PAGE_MASK_16K);
cp0_entry_hi_write(0);
cp0_entry_lo0_write(0);
cp0_entry_lo1_write(0);
/* Clear and initialize TLB. */
for (i = 0; i < TLB_ENTRY_COUNT; i++) {
cp0_index_write(i);
tlbwi();
}
/*
* The kernel is going to make use of some wired
* entries (e.g. mapping kernel stacks in kseg3).
*/
cp0_wired_write(TLB_WIRED);
}
/** Process TLB Refill Exception.
*
* @param istate Interrupted register context.
*/
void tlb_refill(istate_t *istate)
{
entry_lo_t lo;
entry_hi_t hi;
asid_t asid;
uintptr_t badvaddr;
pte_t *pte;
int pfrc;
badvaddr = cp0_badvaddr_read();
mutex_lock(&AS->lock);
asid = AS->asid;
mutex_unlock(&AS->lock);
page_table_lock(AS, true);
pte = find_mapping_and_check(badvaddr, PF_ACCESS_READ, istate, &pfrc);
if (!pte) {
switch (pfrc) {
case AS_PF_FAULT:
goto fail;
break;
case AS_PF_DEFER:
/*
* The page fault came during copy_from_uspace()
* or copy_to_uspace().
*/
page_table_unlock(AS, true);
return;
default:
panic("Unexpected pfrc (%d).", pfrc);
}
}
/*
* Record access to PTE.
*/
pte->a = 1;
tlb_prepare_entry_hi(&hi, asid, badvaddr);
tlb_prepare_entry_lo(&lo, pte->g, pte->p, pte->d, pte->cacheable,
pte->pfn);
/*
* New entry is to be inserted into TLB
*/
cp0_entry_hi_write(hi.value);
if ((badvaddr / PAGE_SIZE) % 2 == 0) {
cp0_entry_lo0_write(lo.value);
cp0_entry_lo1_write(0);
}
else {
cp0_entry_lo0_write(0);
cp0_entry_lo1_write(lo.value);
}
cp0_pagemask_write(TLB_PAGE_MASK_16K);
tlbwr();
page_table_unlock(AS, true);
return;
fail:
page_table_unlock(AS, true);
tlb_refill_fail(istate);
}
/** Process TLB Invalid Exception.
*
* @param istate Interrupted register context.
*/
void tlb_invalid(istate_t *istate)
{
tlb_index_t index;
uintptr_t badvaddr;
entry_lo_t lo;
entry_hi_t hi;
pte_t *pte;
int pfrc;
badvaddr = cp0_badvaddr_read();
/*
* Locate the faulting entry in TLB.
*/
hi.value = cp0_entry_hi_read();
tlb_prepare_entry_hi(&hi, hi.asid, badvaddr);
cp0_entry_hi_write(hi.value);
tlbp();
index.value = cp0_index_read();
page_table_lock(AS, true);
/*
* Fail if the entry is not in TLB.
*/
if (index.p) {
printf("TLB entry not found.\n");
goto fail;
}
pte = find_mapping_and_check(badvaddr, PF_ACCESS_READ, istate, &pfrc);
if (!pte) {
switch (pfrc) {
case AS_PF_FAULT:
goto fail;
break;
case AS_PF_DEFER:
/*
* The page fault came during copy_from_uspace()
* or copy_to_uspace().
*/
page_table_unlock(AS, true);
return;
default:
panic("Unexpected pfrc (%d).", pfrc);
}
}
/*
* Read the faulting TLB entry.
*/
tlbr();
/*
* Record access to PTE.
*/
pte->a = 1;
tlb_prepare_entry_lo(&lo, pte->g, pte->p, pte->d, pte->cacheable,
pte->pfn);
/*
* The entry is to be updated in TLB.
*/
if ((badvaddr / PAGE_SIZE) % 2 == 0)
cp0_entry_lo0_write(lo.value);
else
cp0_entry_lo1_write(lo.value);
cp0_pagemask_write(TLB_PAGE_MASK_16K);
tlbwi();
page_table_unlock(AS, true);
return;
fail:
page_table_unlock(AS, true);
tlb_invalid_fail(istate);
}
/** Process TLB Modified Exception.
*
* @param istate Interrupted register context.
*/
void tlb_modified(istate_t *istate)
{
tlb_index_t index;
uintptr_t badvaddr;
entry_lo_t lo;
entry_hi_t hi;
pte_t *pte;
int pfrc;
badvaddr = cp0_badvaddr_read();
/*
* Locate the faulting entry in TLB.
*/
hi.value = cp0_entry_hi_read();
tlb_prepare_entry_hi(&hi, hi.asid, badvaddr);
cp0_entry_hi_write(hi.value);
tlbp();
index.value = cp0_index_read();
page_table_lock(AS, true);
/*
* Fail if the entry is not in TLB.
*/
if (index.p) {
printf("TLB entry not found.\n");
goto fail;
}
pte = find_mapping_and_check(badvaddr, PF_ACCESS_WRITE, istate, &pfrc);
if (!pte) {
switch (pfrc) {
case AS_PF_FAULT:
goto fail;
break;
case AS_PF_DEFER:
/*
* The page fault came during copy_from_uspace()
* or copy_to_uspace().
*/
page_table_unlock(AS, true);
return;
default:
panic("Unexpected pfrc (%d).", pfrc);
}
}
/*
* Read the faulting TLB entry.
*/
tlbr();
/*
* Record access and write to PTE.
*/
pte->a = 1;
pte->d = 1;
tlb_prepare_entry_lo(&lo, pte->g, pte->p, pte->w, pte->cacheable,
pte->pfn);
/*
* The entry is to be updated in TLB.
*/
if ((badvaddr / PAGE_SIZE) % 2 == 0)
cp0_entry_lo0_write(lo.value);
else
cp0_entry_lo1_write(lo.value);
cp0_pagemask_write(TLB_PAGE_MASK_16K);
tlbwi();
page_table_unlock(AS, true);
return;
fail:
page_table_unlock(AS, true);
tlb_modified_fail(istate);
}
void tlb_refill_fail(istate_t *istate)
{
char *symbol, *sym2;
symbol = symtab_fmt_name_lookup(istate->epc);
sym2 = symtab_fmt_name_lookup(istate->ra);
fault_if_from_uspace(istate, "TLB Refill Exception on %p.",
cp0_badvaddr_read());
panic("%x: TLB Refill Exception at %x (%s<-%s).", cp0_badvaddr_read(),
istate->epc, symbol, sym2);
}
void tlb_invalid_fail(istate_t *istate)
{
char *symbol;
symbol = symtab_fmt_name_lookup(istate->epc);
fault_if_from_uspace(istate, "TLB Invalid Exception on %p.",
cp0_badvaddr_read());
panic("%x: TLB Invalid Exception at %x (%s).", cp0_badvaddr_read(),
istate->epc, symbol);
}
void tlb_modified_fail(istate_t *istate)
{
char *symbol;
symbol = symtab_fmt_name_lookup(istate->epc);
fault_if_from_uspace(istate, "TLB Modified Exception on %p.",
cp0_badvaddr_read());
panic("%x: TLB Modified Exception at %x (%s).", cp0_badvaddr_read(),
istate->epc, symbol);
}
/** Try to find PTE for faulting address.
*
* The AS->lock must be held on entry to this function.
*
* @param badvaddr Faulting virtual address.
* @param access Access mode that caused the fault.
* @param istate Pointer to interrupted state.
* @param pfrc Pointer to variable where as_page_fault() return code
* will be stored.
*
* @return PTE on success, NULL otherwise.
*/
pte_t *
find_mapping_and_check(uintptr_t badvaddr, int access, istate_t *istate,
int *pfrc)
{
entry_hi_t hi;
pte_t *pte;
hi.value = cp0_entry_hi_read();
/*
* Handler cannot succeed if the ASIDs don't match.
*/
if (hi.asid != AS->asid) {
printf("EntryHi.asid=%d, AS->asid=%d\n", hi.asid, AS->asid);
return NULL;
}
/*
* Check if the mapping exists in page tables.
*/
pte = page_mapping_find(AS, badvaddr);
if (pte && pte->p && (pte->w || access != PF_ACCESS_WRITE)) {
/*
* Mapping found in page tables.
* Immediately succeed.
*/
return pte;
} else {
int rc;
/*
* Mapping not found in page tables.
* Resort to higher-level page fault handler.
*/
page_table_unlock(AS, true);
switch (rc = as_page_fault(badvaddr, access, istate)) {
case AS_PF_OK:
/*
* The higher-level page fault handler succeeded,
* The mapping ought to be in place.
*/
page_table_lock(AS, true);
pte = page_mapping_find(AS, badvaddr);
ASSERT(pte && pte->p);
ASSERT(pte->w || access != PF_ACCESS_WRITE);
return pte;
break;
case AS_PF_DEFER:
page_table_lock(AS, true);
*pfrc = AS_PF_DEFER;
return NULL;
break;
case AS_PF_FAULT:
page_table_lock(AS, true);
*pfrc = AS_PF_FAULT;
return NULL;
break;
default:
panic("Unexpected rc (%d).", rc);
}
}
}
void
tlb_prepare_entry_lo(entry_lo_t *lo, bool g, bool v, bool d, bool cacheable,
uintptr_t pfn)
{
lo->value = 0;
lo->g = g;
lo->v = v;
lo->d = d;
lo->c = cacheable ? PAGE_CACHEABLE_EXC_WRITE : PAGE_UNCACHED;
lo->pfn = pfn;
}
void tlb_prepare_entry_hi(entry_hi_t *hi, asid_t asid, uintptr_t addr)
{
hi->value = ALIGN_DOWN(addr, PAGE_SIZE * 2);
hi->asid = asid;
}
/** Print contents of TLB. */
void tlb_print(void)
{
page_mask_t mask;
entry_lo_t lo0, lo1;
entry_hi_t hi, hi_save;
unsigned int i;
hi_save.value = cp0_entry_hi_read();
printf("# ASID VPN2 MASK G V D C PFN\n");
printf("-- ---- ------ ---- - - - - ------\n");
for (i = 0; i < TLB_ENTRY_COUNT; i++) {
cp0_index_write(i);
tlbr();
mask.value = cp0_pagemask_read();
hi.value = cp0_entry_hi_read();
lo0.value = cp0_entry_lo0_read();
lo1.value = cp0_entry_lo1_read();
printf("%-2u %-4u %#6x %#4x %1u %1u %1u %1u %#6x\n",
i, hi.asid, hi.vpn2, mask.mask,
lo0.g, lo0.v, lo0.d, lo0.c, lo0.pfn);
printf(" %1u %1u %1u %1u %#6x\n",
lo1.g, lo1.v, lo1.d, lo1.c, lo1.pfn);
}
cp0_entry_hi_write(hi_save.value);
}
/** Invalidate all not wired TLB entries. */
void tlb_invalidate_all(void)
{
ipl_t ipl;
entry_lo_t lo0, lo1;
entry_hi_t hi_save;
int i;
hi_save.value = cp0_entry_hi_read();
ipl = interrupts_disable();
for (i = TLB_WIRED; i < TLB_ENTRY_COUNT; i++) {
cp0_index_write(i);
tlbr();
lo0.value = cp0_entry_lo0_read();
lo1.value = cp0_entry_lo1_read();
lo0.v = 0;
lo1.v = 0;
cp0_entry_lo0_write(lo0.value);
cp0_entry_lo1_write(lo1.value);
tlbwi();
}
interrupts_restore(ipl);
cp0_entry_hi_write(hi_save.value);
}
/** Invalidate all TLB entries belonging to specified address space.
*
* @param asid Address space identifier.
*/
void tlb_invalidate_asid(asid_t asid)
{
ipl_t ipl;
entry_lo_t lo0, lo1;
entry_hi_t hi, hi_save;
int i;
ASSERT(asid != ASID_INVALID);
hi_save.value = cp0_entry_hi_read();
ipl = interrupts_disable();
for (i = 0; i < TLB_ENTRY_COUNT; i++) {
cp0_index_write(i);
tlbr();
hi.value = cp0_entry_hi_read();
if (hi.asid == asid) {
lo0.value = cp0_entry_lo0_read();
lo1.value = cp0_entry_lo1_read();
lo0.v = 0;
lo1.v = 0;
cp0_entry_lo0_write(lo0.value);
cp0_entry_lo1_write(lo1.value);
tlbwi();
}
}
interrupts_restore(ipl);
cp0_entry_hi_write(hi_save.value);
}
/** Invalidate TLB entries for specified page range belonging to specified
* address space.
*
* @param asid Address space identifier.
* @param page First page whose TLB entry is to be invalidated.
* @param cnt Number of entries to invalidate.
*/
void tlb_invalidate_pages(asid_t asid, uintptr_t page, size_t cnt)
{
unsigned int i;
ipl_t ipl;
entry_lo_t lo0, lo1;
entry_hi_t hi, hi_save;
tlb_index_t index;
ASSERT(asid != ASID_INVALID);
hi_save.value = cp0_entry_hi_read();
ipl = interrupts_disable();
for (i = 0; i < cnt + 1; i += 2) {
hi.value = 0;
tlb_prepare_entry_hi(&hi, asid, page + i * PAGE_SIZE);
cp0_entry_hi_write(hi.value);
tlbp();
index.value = cp0_index_read();
if (!index.p) {
/*
* Entry was found, index register contains valid
* index.
*/
tlbr();
lo0.value = cp0_entry_lo0_read();
lo1.value = cp0_entry_lo1_read();
lo0.v = 0;
lo1.v = 0;
cp0_entry_lo0_write(lo0.value);
cp0_entry_lo1_write(lo1.value);
tlbwi();
}
}
interrupts_restore(ipl);
cp0_entry_hi_write(hi_save.value);
}
/** @}
*/