/* arch/sparc64/kernel/ktlb.S: Kernel mapping TLB miss handling.
*
* Copyright (C) 1995, 1997, 2005 David S. Miller <davem@davemloft.net>
* Copyright (C) 1996 Eddie C. Dost (ecd@brainaid.de)
* Copyright (C) 1996 Miguel de Icaza (miguel@nuclecu.unam.mx)
* Copyright (C) 1996,98,99 Jakub Jelinek (jj@sunsite.mff.cuni.cz)
*/
#include <linux/config.h>
#include <asm/head.h>
#include <asm/asi.h>
#include <asm/page.h>
#include <asm/pgtable.h>
.text
.align 32
/*
* On a second level vpte miss, check whether the original fault is to the OBP
* range (note that this is only possible for instruction miss, data misses to
* obp range do not use vpte). If so, go back directly to the faulting address.
* This is because we want to read the tpc, otherwise we have no way of knowing
* the 8k aligned faulting address if we are using >8k kernel pagesize. This
* also ensures no vpte range addresses are dropped into tlb while obp is
* executing (see inherit_locked_prom_mappings() rant).
*/
sparc64_vpte_nucleus:
/* Note that kvmap below has verified that the address is
* in the range MODULES_VADDR --> VMALLOC_END already. So
* here we need only check if it is an OBP address or not.
*/
sethi %hi(LOW_OBP_ADDRESS), %g5
cmp %g4, %g5
blu,pn %xcc, kern_vpte
mov 0x1, %g5
sllx %g5, 32, %g5
cmp %g4, %g5
blu,pn %xcc, vpte_insn_obp
nop
/* These two instructions are patched by paginig_init(). */
kern_vpte:
sethi %hi(swapper_pgd_zero), %g5
lduw [%g5 + %lo(swapper_pgd_zero)], %g5
/* With kernel PGD in %g5, branch back into dtlb_backend. */
ba,pt %xcc, sparc64_kpte_continue
andn %g1, 0x3, %g1 /* Finish PMD offset adjustment. */
vpte_noent:
/* Restore previous TAG_ACCESS, %g5 is zero, and we will
* skip over the trap instruction so that the top level
* TLB miss handler will thing this %g5 value is just an
* invalid PTE, thus branching to full fault processing.
*/
mov TLB_SFSR, %g1
stxa %g4, [%g1 + %g1] ASI_DMMU
done
vpte_insn_obp:
sethi %hi(prom_pmd_phys), %g5
ldx [%g5 + %lo(prom_pmd_phys)], %g5
/* Behave as if we are at TL0. */
wrpr %g0, 1, %tl
rdpr %tpc, %g4 /* Find original faulting iaddr */
srlx %g4, 13, %g4 /* Throw out context bits */
sllx %g4, 13, %g4 /* g4 has vpn + ctx0 now */
/* Restore previous TAG_ACCESS. */
mov TLB_SFSR, %g1
stxa %g4, [%g1 + %g1] ASI_IMMU
/* Get PMD offset. */
srlx %g4, 23, %g6
and %g6, 0x7ff, %g6
sllx %g6, 2, %g6
/* Load PMD, is it valid? */
lduwa [%g5 + %g6] ASI_PHYS_USE_EC, %g5
brz,pn %g5, longpath
sllx %g5, 11, %g5
/* Get PTE offset. */
srlx %g4, 13, %g6
and %g6, 0x3ff, %g6
sllx %g6, 3, %g6
/* Load PTE. */
ldxa [%g5 + %g6] ASI_PHYS_USE_EC, %g5
brgez,pn %g5, longpath
nop
/* TLB load and return from trap. */
stxa %g5, [%g0] ASI_ITLB_DATA_IN
retry
kvmap_do_obp:
sethi %hi(prom_pmd_phys), %g5
ldx [%g5 + %lo(prom_pmd_phys)], %g5
/* Get PMD offset. */
srlx %g4, 23, %g6
and %g6, 0x7ff, %g6
sllx %g6, 2, %g6
/* Load PMD, is it valid? */
lduwa [%g5 + %g6] ASI_PHYS_USE_EC, %g5
brz,pn %g5, longpath
sllx %g5, 11, %g5
/* Get PTE offset. */
srlx %g4, 13, %g6
and %g6, 0x3ff, %g6
sllx %g6, 3, %g6
/* Load PTE. */
ldxa [%g5 + %g6] ASI_PHYS_USE_EC, %g5
brgez,pn %g5, longpath
nop
/* TLB load and return from trap. */
stxa %g5, [%g0] ASI_DTLB_DATA_IN
retry
/*
* On a first level data miss, check whether this is to the OBP range (note
* that such accesses can be made by prom, as well as by kernel using
* prom_getproperty on "address"), and if so, do not use vpte access ...
* rather, use information saved during inherit_prom_mappings() using 8k
* pagesize.
*/
.align 32
kvmap:
brlz,pt %g4, kvmap_load
xor %g2, %g4, %g5
kvmap_nonlinear:
sethi %hi(MODULES_VADDR), %g5
cmp %g4, %g5
blu,pn %xcc, longpath
mov (VMALLOC_END >> 24), %g5
sllx %g5, 24, %g5
cmp %g4, %g5
bgeu,pn %xcc, longpath
nop
kvmap_check_obp:
sethi %hi(LOW_OBP_ADDRESS), %g5
cmp %g4, %g5
blu,pn %xcc, kvmap_vmalloc_addr
mov 0x1, %g5
sllx %g5, 32, %g5
cmp %g4, %g5
blu,pn %xcc, kvmap_do_obp
nop
kvmap_vmalloc_addr:
/* If we get here, a vmalloc addr was accessed, load kernel VPTE. */
ldxa [%g3 + %g6] ASI_N, %g5
brgez,pn %g5, longpath
nop
kvmap_load:
/* PTE is valid, load into TLB and return from trap. */
stxa %g5, [%g0] ASI_DTLB_DATA_IN ! Reload TLB
retry
