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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.
*/
#include <arch/mm/tlb.h>
#include <arch/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 <symtab.h>
#include <synch/spinlock.h>
#include <print.h>
#include <debug.h>
static void tlb_refill_fail(struct exception_regdump *pstate);
static void tlb_invalid_fail(struct exception_regdump *pstate);
static void tlb_modified_fail(struct exception_regdump *pstate);
static pte_t *find_mapping_and_check(__address badvaddr);
static void prepare_entry_lo(entry_lo_t *lo, bool g, bool v, bool d, int c, __address pfn);
static void prepare_entry_hi(entry_hi_t *hi, asid_t asid, __address addr);
/** Initialize TLB
*
* 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
*
* Process TLB Refill Exception.
*
* @param pstate Interrupted register context.
*/
void tlb_refill(struct exception_regdump *pstate)
{
entry_lo_t lo;
entry_hi_t hi;
__address badvaddr;
pte_t *pte;
badvaddr = cp0_badvaddr_read();
spinlock_lock(&AS->lock);
pte = find_mapping_and_check(badvaddr);
if (!pte)
goto fail;
/*
* Record access to PTE.
*/
pte->a = 1;
prepare_entry_hi(&hi, AS->asid, badvaddr);
prepare_entry_lo(&lo, pte->lo.g, pte->lo.v, pte->lo.d, pte->lo.c, pte->lo.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();
spinlock_unlock(&AS->lock);
return;
fail:
spinlock_unlock(&AS->lock);
tlb_refill_fail(pstate);
}
/** Process TLB Invalid Exception
*
* Process TLB Invalid Exception.
*
* @param pstate Interrupted register context.
*/
void tlb_invalid(struct exception_regdump *pstate)
{
tlb_index_t index;
__address badvaddr;
entry_lo_t lo;
entry_hi_t hi;
pte_t *pte;
badvaddr = cp0_badvaddr_read();
/*
* Locate the faulting entry in TLB.
*/
hi.value = cp0_entry_hi_read();
prepare_entry_hi(&hi, hi.asid, badvaddr);
cp0_entry_hi_write(hi.value);
tlbp();
index.value = cp0_index_read();
spinlock_lock(&AS->lock);
/*
* 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);
if (!pte)
goto fail;
/*
* Read the faulting TLB entry.
*/
tlbr();
/*
* Record access to PTE.
*/
pte->a = 1;
prepare_entry_lo(&lo, pte->lo.g, pte->lo.v, pte->lo.d, pte->lo.c, pte->lo.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();
spinlock_unlock(&AS->lock);
return;
fail:
spinlock_unlock(&AS->lock);
tlb_invalid_fail(pstate);
}
/** Process TLB Modified Exception
*
* Process TLB Modified Exception.
*
* @param pstate Interrupted register context.
*/
void tlb_modified(struct exception_regdump *pstate)
{
tlb_index_t index;
__address badvaddr;
entry_lo_t lo;
entry_hi_t hi;
pte_t *pte;
badvaddr = cp0_badvaddr_read();
/*
* Locate the faulting entry in TLB.
*/
hi.value = cp0_entry_hi_read();
prepare_entry_hi(&hi, hi.asid, badvaddr);
cp0_entry_hi_write(hi.value);
tlbp();
index.value = cp0_index_read();
spinlock_lock(&AS->lock);
/*
* 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);
if (!pte)
goto fail;
/*
* Fail if the page is not writable.
*/
if (!pte->w)
goto fail;
/*
* Read the faulting TLB entry.
*/
tlbr();
/*
* Record access and write to PTE.
*/
pte->a = 1;
pte->lo.d = 1;
prepare_entry_lo(&lo, pte->lo.g, pte->lo.v, pte->w, pte->lo.c, pte->lo.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();
spinlock_unlock(&AS->lock);
return;
fail:
spinlock_unlock(&AS->lock);
tlb_modified_fail(pstate);
}
void tlb_refill_fail(struct exception_regdump *pstate)
{
char *symbol = "";
char *sym2 = "";
char *s = get_symtab_entry(pstate->epc);
if (s)
symbol = s;
s = get_symtab_entry(pstate->ra);
if (s)
sym2 = s;
panic("%X: TLB Refill Exception at %X(%s<-%s)\n", cp0_badvaddr_read(), pstate->epc, symbol, sym2);
}
void tlb_invalid_fail(struct exception_regdump *pstate)
{
char *symbol = "";
char *s = get_symtab_entry(pstate->epc);
if (s)
symbol = s;
panic("%X: TLB Invalid Exception at %X(%s)\n", cp0_badvaddr_read(), pstate->epc, symbol);
}
void tlb_modified_fail(struct exception_regdump *pstate)
{
char *symbol = "";
char *s = get_symtab_entry(pstate->epc);
if (s)
symbol = s;
panic("%X: TLB Modified Exception at %X(%s)\n", cp0_badvaddr_read(), pstate->epc, symbol);
}
/** Try to find PTE for faulting address
*
* Try to find PTE for faulting address.
* The AS->lock must be held on entry to this function.
*
* @param badvaddr Faulting virtual address.
*
* @return PTE on success, NULL otherwise.
*/
pte_t *find_mapping_and_check(__address badvaddr)
{
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(badvaddr, AS->asid, 0);
if (pte && pte->lo.v) {
/*
* Mapping found in page tables.
* Immediately succeed.
*/
return pte;
} else {
/*
* Mapping not found in page tables.
* Resort to higher-level page fault handler.
*/
if (as_page_fault(badvaddr)) {
/*
* The higher-level page fault handler succeeded,
* The mapping ought to be in place.
*/
pte = page_mapping_find(badvaddr, AS->asid, 0);
ASSERT(pte && pte->lo.v);
return pte;
}
}
/*
* Handler cannot succeed if badvaddr has no mapping.
*/
if (!pte) {
printf("No such mapping.\n");
return NULL;
}
/*
* Handler cannot succeed if the mapping is marked as invalid.
*/
if (!pte->lo.v) {
printf("Invalid mapping.\n");
return NULL;
}
return pte;
}
void prepare_entry_lo(entry_lo_t *lo, bool g, bool v, bool d, int c, __address pfn)
{
lo->value = 0;
lo->g = g;
lo->v = v;
lo->d = d;
lo->c = c;
lo->pfn = pfn;
}
void prepare_entry_hi(entry_hi_t *hi, asid_t asid, __address addr)
{
hi->value = (((addr/PAGE_SIZE)/2)*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;
int i;
hi_save.value = cp0_entry_hi_read();
printf("TLB:\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("%d: asid=%d, vpn2=%d, mask=%d\tg[0]=%d, v[0]=%d, d[0]=%d, c[0]=%B, pfn[0]=%d\n"
"\t\t\t\tg[1]=%d, v[1]=%d, d[1]=%d, c[1]=%B, pfn[1]=%d\n",
i, hi.asid, hi.vpn2, mask.mask, lo0.g, lo0.v, lo0.d, lo0.c, lo0.pfn,
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 entry for specified page belonging to specified address space.
*
* @param asid Address space identifier.
* @param page Page whose TLB entry is to be invalidated.
*/
void tlb_invalidate_page(asid_t asid, __address page)
{
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();
hi.value = 0;
prepare_entry_hi(&hi, asid, page);
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);
}