/** Try to find PTE for faulting address
*
* @param as Address space.
* @param badvaddr Faulting virtual address.
* @param access Access mode that caused the fault.
* @param istate Pointer to interrupted state.
*
* @return PTE on success, NULL otherwise.
*
*/
static pte_t *find_mapping_and_check(as_t *as, uintptr_t badvaddr, int access,
istate_t *istate)
{
/*
* Check if the mapping exists in page tables.
*/
pte_t *pte = page_mapping_find(as, badvaddr, true);
if ((pte) && (pte->present)) {
/*
* Mapping found in page tables.
* Immediately succeed.
*/
return pte;
}
/*
* Mapping not found in page tables.
* Resort to higher-level page fault handler.
*/
if (as_page_fault(badvaddr, access, istate) == AS_PF_OK) {
/*
* The higher-level page fault handler succeeded,
* The mapping ought to be in place.
*/
pte = page_mapping_find(as, badvaddr, true);
ASSERT((pte) && (pte->present));
return pte;
}
return NULL;
}
/** Try to find PTE for faulting address.
*
* @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.
*
*/
static pte_t *find_mapping_and_check(uintptr_t badvaddr, int access,
istate_t *istate, int *pfrc)
{
entry_hi_t hi;
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_t *pte = page_mapping_find(AS, badvaddr, true);
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.
*/
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.
*/
pte = page_mapping_find(AS, badvaddr, true);
ASSERT(pte);
ASSERT(pte->p);
ASSERT((pte->w) || (access != PF_ACCESS_WRITE));
return pte;
case AS_PF_DEFER:
*pfrc = AS_PF_DEFER;
return NULL;
case AS_PF_FAULT:
*pfrc = AS_PF_FAULT;
return NULL;
default:
panic("Unexpected return code (%d).", rc);
}
}
}
void page_fault(unsigned int n __attribute__((unused)), istate_t *istate)
{
uint32_t fault_status = asi_u32_read(ASI_MMUREGS, MMU_FAULT_STATUS);
uintptr_t fault_address = asi_u32_read(ASI_MMUREGS, MMU_FAULT_ADDRESS);
mmu_fault_status_t *fault = (mmu_fault_status_t *) &fault_status;
mmu_fault_type_t type = (mmu_fault_type_t) fault->at;
if ((type == FAULT_TYPE_LOAD_USER_DATA) ||
(type == FAULT_TYPE_LOAD_SUPERVISOR_DATA))
as_page_fault(fault_address, PF_ACCESS_READ, istate);
if ((type == FAULT_TYPE_EXECUTE_USER) ||
(type == FAULT_TYPE_EXECUTE_SUPERVISOR))
as_page_fault(fault_address, PF_ACCESS_EXEC, istate);
if ((type == FAULT_TYPE_STORE_USER_DATA) ||
(type == FAULT_TYPE_STORE_USER_INSTRUCTION) ||
(type == FAULT_TYPE_STORE_SUPERVISOR_INSTRUCTION) ||
(type == FAULT_TYPE_STORE_SUPERVISOR_DATA))
as_page_fault(fault_address, PF_ACCESS_WRITE, istate);
}
void page_fault(unsigned int n, istate_t *istate)
{
uintptr_t badvaddr = read_cr2();
if (istate->error_word & PFERR_CODE_RSVD)
panic("Reserved bit set in page table entry.");
pf_access_t access;
if (istate->error_word & PFERR_CODE_RW)
access = PF_ACCESS_WRITE;
else if (istate->error_word & PFERR_CODE_ID)
access = PF_ACCESS_EXEC;
else
access = PF_ACCESS_READ;
(void) as_page_fault(badvaddr, access, istate);
}
/** Try to find PTE for faulting address
*
* @param as Address space.
* @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.
*
*/
static pte_t *find_mapping_and_check(as_t *as, uintptr_t badvaddr, int access,
istate_t *istate, int *pfrc)
{
/*
* Check if the mapping exists in page tables.
*/
pte_t *pte = page_mapping_find(as, badvaddr, true);
if ((pte) && (pte->present)) {
/*
* Mapping found in page tables.
* Immediately succeed.
*/
return pte;
} else {
/*
* Mapping not found in page tables.
* Resort to higher-level page fault handler.
*/
int rc = as_page_fault(badvaddr, access, istate);
switch (rc) {
case AS_PF_OK:
/*
* The higher-level page fault handler succeeded,
* The mapping ought to be in place.
*/
pte = page_mapping_find(as, badvaddr, true);
ASSERT((pte) && (pte->present));
*pfrc = 0;
return pte;
case AS_PF_DEFER:
*pfrc = rc;
return NULL;
case AS_PF_FAULT:
*pfrc = rc;
return NULL;
default:
panic("Unexpected rc (%d).", rc);
}
}
}
/** Try to find PTE for faulting address.
*
* @param badvaddr Faulting virtual address.
* @param access Access mode that caused the fault.
* @param istate Pointer to interrupted state.
*
* @return PTE on success, NULL otherwise.
*
*/
static pte_t *find_mapping_and_check(uintptr_t badvaddr, int access,
istate_t *istate)
{
entry_hi_t hi;
hi.value = cp0_entry_hi_read();
ASSERT(hi.asid == AS->asid);
/*
* Check if the mapping exists in page tables.
*/
pte_t *pte = page_mapping_find(AS, badvaddr, true);
if ((pte) && (pte->p) && ((pte->w) || (access != PF_ACCESS_WRITE))) {
/*
* Mapping found in page tables.
* Immediately succeed.
*/
return pte;
}
/*
* Mapping not found in page tables.
* Resort to higher-level page fault handler.
*/
if (as_page_fault(badvaddr, access, istate) == AS_PF_OK) {
/*
* The higher-level page fault handler succeeded,
* The mapping ought to be in place.
*/
pte = page_mapping_find(AS, badvaddr, true);
ASSERT(pte);
ASSERT(pte->p);
ASSERT((pte->w) || (access != PF_ACCESS_WRITE));
return pte;
}
return NULL;
}
