/* tlb-miss.S: TLB miss handlers
*
* Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#include <linux/sys.h>
#include <linux/linkage.h>
#include <asm/page.h>
#include <asm/pgtable.h>
#include <asm/highmem.h>
#include <asm/spr-regs.h>
.section .text.tlbmiss
.balign 4
.globl __entry_insn_mmu_miss
__entry_insn_mmu_miss:
break
nop
.globl __entry_insn_mmu_exception
__entry_insn_mmu_exception:
break
nop
.globl __entry_data_mmu_miss
__entry_data_mmu_miss:
break
nop
.globl __entry_data_mmu_exception
__entry_data_mmu_exception:
break
nop
###############################################################################
#
# handle a lookup failure of one sort or another in a kernel TLB handler
# On entry:
# GR29 - faulting address
# SCR2 - saved CCR
#
###############################################################################
.type __tlb_kernel_fault,@function
__tlb_kernel_fault:
# see if we're supposed to re-enable single-step mode upon return
sethi.p %hi(__break_tlb_miss_return_break),gr30
setlo %lo(__break_tlb_miss_return_break),gr30
movsg pcsr,gr31
subcc gr31,gr30,gr0,icc0
beq icc0,#0,__tlb_kernel_fault_sstep
movsg scr2,gr30
movgs gr30,ccr
movgs gr29,scr2 /* save EAR0 value */
sethi.p %hi(__kernel_current_task),gr29
setlo %lo(__kernel_current_task),gr29
ldi.p @(gr29,#0),gr29 /* restore GR29 */
bra __entry_kernel_handle_mmu_fault
# we've got to re-enable single-stepping
__tlb_kernel_fault_sstep:
sethi.p %hi(__break_tlb_miss_real_return_info),gr30
setlo %lo(__break_tlb_miss_real_return_info),gr30
lddi @(gr30,0),gr30
movgs gr30,pcsr
movgs gr31,psr
movsg scr2,gr30
movgs gr30,ccr
movgs gr29,scr2 /* save EAR0 value */
sethi.p %hi(__kernel_current_task),gr29
setlo %lo(__kernel_current_task),gr29
ldi.p @(gr29,#0),gr29 /* restore GR29 */
bra __entry_kernel_handle_mmu_fault_sstep
.size __tlb_kernel_fault, .-__tlb_kernel_fault
###############################################################################
#
# handle a lookup failure of one sort or another in a user TLB handler
# On entry:
# GR28 - faulting address
# SCR2 - saved CCR
#
###############################################################################
.type __tlb_user_fault,@function
__tlb_user_fault:
# see if we're supposed to re-enable single-step mode upon return
sethi.p %hi(__break_tlb_miss_return_break),gr30
setlo %lo(__break_tlb_miss_return_break),gr30
movsg pcsr,gr31
subcc gr31,gr30,gr0,icc0
beq icc0,#0,__tlb_user_fault_sstep
movsg scr2,gr30
movgs gr30,ccr
bra __entry_uspace_handle_mmu_fault
# we've got to re-enable single-stepping
__tlb_user_fault_sstep:
sethi.p %hi(__break_tlb_miss_real_return_info),gr30
setlo %lo(__break_tlb_miss_real_return_info),gr30
lddi @(gr30,0),gr30
movgs gr30,pcsr
movgs gr31,psr
movsg scr2,gr30
movgs gr30,ccr
bra __entry_uspace_handle_mmu_fault_sstep
.size __tlb_user_fault, .-__tlb_user_fault
###############################################################################
#
# Kernel instruction TLB miss handler
# On entry:
# GR1 - kernel stack pointer
# GR28 - saved exception frame pointer
# GR29 - faulting address
# GR31 - EAR0 ^ SCR0
# SCR0 - base of virtual range covered by cached PGE from last ITLB miss (or 0xffffffff)
# DAMR3 - mapped page directory
# DAMR4 - mapped page table as matched by SCR0
#
###############################################################################
.globl __entry_kernel_insn_tlb_miss
.type __entry_kernel_insn_tlb_miss,@function
__entry_kernel_insn_tlb_miss:
#if 0
sethi.p %hi(0xe1200004),gr30
setlo %lo(0xe1200004),gr30
st gr0,@(gr30,gr0)
sethi.p %hi(0xffc00100),gr30
setlo %lo(0xffc00100),gr30
sth gr30,@(gr30,gr0)
membar
#endif
movsg ccr,gr30 /* save CCR */
movgs gr30,scr2
# see if the cached page table mapping is appropriate
srlicc.p gr31,#26,gr0,icc0
setlos 0x3ffc,gr30
srli.p gr29,#12,gr31 /* use EAR0[25:14] as PTE index */
bne icc0,#0,__itlb_k_PTD_miss
__itlb_k_PTD_mapped:
# access the PTD with EAR0[25:14]
# - DAMLR4 points to the virtual address of the appropriate page table
# - the PTD holds 4096 PTEs
# - the PTD must be accessed uncached
# - the PTE must be marked accessed if it was valid
#
and gr31,gr30,gr31
movsg damlr4,gr30
add gr30,gr31,gr31
ldi @(gr31,#0),gr30 /* fetch the PTE */
andicc gr30,#_PAGE_PRESENT,gr0,icc0
ori.p gr30,#_PAGE_ACCESSED,gr30
beq icc0,#0,__tlb_kernel_fault /* jump if PTE invalid */
sti.p gr30,@(gr31,#0) /* update the PTE */
andi gr30,#~_PAGE_ACCESSED,gr30
# we're using IAMR1 as an extra TLB entry
# - punt the entry here (if valid) to the real TLB and then replace with the new PTE
# - need to check DAMR1 lest we cause an multiple-DAT-hit exception
# - IAMPR1 has no WP bit, and we mustn't lose WP information
movsg iampr1,gr31
andicc gr31,#xAMPRx_V,gr0,icc0
setlos.p 0xfffff000,gr31
beq icc0,#0,__itlb_k_nopunt /* punt not required */
movsg iamlr1,gr31
movgs gr31,tplr /* set TPLR.CXN */
tlbpr gr31,gr0,#4,#0 /* delete matches from TLB, IAMR1, DAMR1 */
movsg dampr1,gr31
ori gr31,#xAMPRx_V,gr31 /* entry was invalidated by tlbpr #4 */
movgs gr31,tppr
movsg iamlr1,gr31 /* set TPLR.CXN */
movgs gr31,tplr
tlbpr gr31,gr0,#2,#0 /* save to the TLB */
movsg tpxr,gr31 /* check the TLB write error flag */
andicc.p gr31,#TPXR_E,gr0,icc0
setlos #0xfffff000,gr31
bne icc0,#0,__tlb_kernel_fault
__itlb_k_nopunt:
# assemble the new TLB entry
and gr29,gr31,gr29
movsg cxnr,gr31
or gr29,gr31,gr29
movgs gr29,iamlr1 /* xAMLR = address | context number */
movgs gr30,iampr1
movgs gr29,damlr1
movgs gr30,dampr1
# return, restoring registers
movsg scr2,gr30
movgs gr30,ccr
sethi.p %hi(__kernel_current_task),gr29
setlo %lo(__kernel_current_task),gr29
ldi @(gr29,#0),gr29
rett #0
beq icc0,#3,0 /* prevent icache prefetch */
# the PTE we want wasn't in the PTD we have mapped, so we need to go looking for a more
# appropriate page table and map that instead
# - access the PGD with EAR0[31:26]
# - DAMLR3 points to the virtual address of the page directory
# - the PGD holds 64 PGEs and each PGE/PME points to a set of page tables
__itlb_k_PTD_miss:
srli gr29,#26,gr31 /* calculate PGE offset */
slli gr31,#8,gr31 /* and clear bottom bits */
movsg damlr3,gr30
ld @(gr31,gr30),gr30 /* access the PGE */
andicc.p gr30,#_PAGE_PRESENT,gr0,icc0
andicc gr30,#xAMPRx_SS,gr0,icc1
# map this PTD instead and record coverage address
ori.p gr30,#xAMPRx_L|xAMPRx_SS_16Kb|xAMPRx_S|xAMPRx_C|xAMPRx_V,gr30
beq icc0,#0,__tlb_kernel_fault /* jump if PGE not present */
slli.p gr31,#18,gr31
bne icc1,#0,__itlb_k_bigpage
movgs gr30,dampr4
movgs gr31,scr0
# we can now resume normal service
setlos 0x3ffc,gr30
srli.p gr29,#12,gr31 /* use EAR0[25:14] as PTE index */
bra __itlb_k_PTD_mapped
__itlb_k_bigpage:
break
nop
.size __entry_kernel_insn_tlb_miss, .-__entry_kernel_insn_tlb_miss
###############################################################################
#
# Kernel data TLB miss handler
# On entry:
# GR1 - kernel stack pointer
# GR28 - saved exception frame pointer
# GR29 - faulting address
# GR31 - EAR0 ^ SCR1
# SCR1 - base of virtual range covered by cached PGE from last DTLB miss (or 0xffffffff)
# DAMR3 - mapped page directory
# DAMR5 - mapped page table as matched by SCR1
#
###############################################################################
.globl __entry_kernel_data_tlb_miss
.type __entry_kernel_data_tlb_miss,@function
__entry_kernel_data_tlb_miss:
#if 0
sethi.p %hi(0xe1200004),gr30
setlo %lo(0xe1200004),gr30
st gr0,@(gr30,gr0)
sethi.p %hi(0xffc00100),gr30
setlo %lo(0xffc00100),gr30
sth gr30,@(gr30,gr0)
membar
#endif
movsg ccr,gr30 /* save CCR */
movgs gr30,scr2
# see if the cached page table mapping is appropriate
srlicc.p gr31,#26,gr0,icc0
setlos 0x3ffc,gr30
srli.p gr29,#12,gr31 /* use EAR0[25:14] as PTE index */
bne icc0,#0,__dtlb_k_PTD_miss
__dtlb_k_PTD_mapped:
# access the PTD with EAR0[25:14]
# - DAMLR5 points to the virtual address of the appropriate page table
# - the PTD holds 4096 PTEs
# - the PTD must be accessed uncached
# - the PTE must be marked accessed if it was valid
#
and gr31,gr30,gr31
movsg damlr5,gr30
add gr30,gr31,gr31
ldi @(gr31,#0),gr30 /* fetch the PTE */
andicc gr30,#_PAGE_PRESENT,gr0,icc0
ori.p gr30,#_PAGE_ACCESSED,gr30
beq icc0,#0,__tlb_kernel_fault /* jump if PTE invalid */
sti.p gr30,@(gr31,#0) /* update the PTE */
andi gr30,#~_PAGE_ACCESSED,gr30
# we're using DAMR1 as an extra TLB entry
# - punt the entry here (if valid) to the real TLB and then replace with the new PTE
# - need to check IAMR1 lest we cause an multiple-DAT-hit exception
movsg dampr1,gr31
andicc gr31,#xAMPRx_V,gr0,icc0
setlos.p 0xfffff000,gr31
beq icc0,#0,__dtlb_k_nopunt /* punt not required */
movsg damlr1,gr31
movgs gr31,tplr /* set TPLR.CXN */
tlbpr gr31,gr0,#4,#0 /* delete matches from TLB, IAMR1, DAMR1 */
movsg dampr1,gr31
ori gr31,#xAMPRx_V,gr31 /* entry was invalidated by tlbpr #4 */
movgs gr31,tppr
movsg damlr1,gr31 /* set TPLR.CXN */
movgs gr31,tplr
tlbpr gr31,gr0,#2,#0 /* save to the TLB */
movsg tpxr,gr31 /* check the TLB write error flag */
andicc.p gr31,#TPXR_E,gr0,icc0
setlos #0xfffff000,gr31
bne icc0,#0,__tlb_kernel_fault
__dtlb_k_nopunt:
# assemble the new TLB entry
and gr29,gr31,gr29
movsg cxnr,gr31
or gr29,gr31,gr29
movgs gr29,iamlr1 /* xAMLR = address | context number */
movgs gr30,iampr1
movgs gr29,damlr1
movgs gr30,dampr1
# return, restoring registers
movsg scr2,gr30
movgs gr30,ccr
sethi.p %hi(__kernel_current_task),gr29
setlo %lo(__kernel_current_task),gr29
ldi @(gr29,#0),gr29
rett #0
beq icc0,#3,0 /* prevent icache prefetch */
# the PTE we want wasn't in the PTD we have mapped, so we need to go looking for a more
# appropriate page table and map that instead
# - access the PGD with EAR0[31:26]
# - DAMLR3 points to the virtual address of the page directory
# - the PGD holds 64 PGEs and each PGE/PME points to a set of page tables
__dtlb_k_PTD_miss:
srli gr29,#26,gr31 /* calculate PGE offset */
slli gr31,#8,gr31 /* and clear bottom bits */
movsg damlr3,gr30
ld @(gr31,gr30),gr30 /* access the PGE */
andicc.p gr30,#_PAGE_PRESENT,gr0,icc0
andicc gr30,#xAMPRx_SS,gr0,icc1
# map this PTD instead and record coverage address
ori.p gr30,#xAMPRx_L|xAMPRx_SS_16Kb|xAMPRx_S|xAMPRx_C|xAMPRx_V,gr30
beq icc0,#0,__tlb_kernel_fault /* jump if PGE not present */
slli.p gr31,#18,gr31
bne icc1,#0,__dtlb_k_bigpage
movgs gr30,dampr5
movgs gr31,scr1
# we can now resume normal service
setlos 0x3ffc,gr30
srli.p gr29,#12,gr31 /* use EAR0[25:14] as PTE index */
bra __dtlb_k_PTD_mapped
__dtlb_k_bigpage:
break
nop
.size __entry_kernel_data_tlb_miss, .-__entry_kernel_data_tlb_miss
###############################################################################
#
# Userspace instruction TLB miss handler (with PGE prediction)
# On entry:
# GR28 - faulting address
# GR31 - EAR0 ^ SCR0
# SCR0 - base of virtual range covered by cached PGE from last ITLB miss (or 0xffffffff)
# DAMR3 - mapped page directory
# DAMR4 - mapped page table as matched by SCR0
#
###############################################################################
.globl __entry_user_insn_tlb_miss
.type __entry_user_insn_tlb_miss,@function
__entry_user_insn_tlb_miss:
#if 0
sethi.p %hi(0xe1200004),gr30
setlo %lo(0xe1200004),gr30
st gr0,@(gr30,gr0)
sethi.p %hi(0xffc00100),gr30
setlo %lo(0xffc00100),gr30
sth gr30,@(gr30,gr0)
membar
#endif
movsg ccr,gr30 /* save CCR */
movgs gr30,scr2
# see if the cached page table mapping is appropriate
srlicc.p gr31,#26,gr0,icc0
setlos 0x3ffc,gr30
srli.p gr28,#12,gr31 /* use EAR0[25:14] as PTE index */
bne icc0,#0,__itlb_u_PTD_miss
__itlb_u_PTD_mapped:
# access the PTD with EAR0[25:14]
# - DAMLR4 points to the virtual address of the appropriate page table
# - the PTD holds 4096 PTEs
# - the PTD must be accessed uncached
# - the PTE must be marked accessed if it was valid
#
and gr31,gr30,gr31
movsg damlr4,gr30
add gr30,gr31,gr31
ldi @(gr31,#0),gr30 /* fetch the PTE */
andicc gr30,#_PAGE_PRESENT,gr0,icc0
ori.p gr30,#_PAGE_ACCESSED,gr30
beq icc0,#0,__tlb_user_fault /* jump if PTE invalid */
sti.p gr30,@(gr31,#0) /* update the PTE */
andi gr30,#~_PAGE_ACCESSED,gr30
# we're using IAMR1/DAMR1 as an extra TLB entry
# - punt the entry here (if valid) to the real TLB and then replace with the new PTE
movsg dampr1,gr31
andicc gr31,#xAMPRx_V,gr0,icc0
setlos.p 0xfffff000,gr31
beq icc0,#0,__itlb_u_nopunt /* punt not required */
movsg dampr1,gr31
movgs gr31,tppr
movsg damlr1,gr31 /* set TPLR.CXN */
movgs gr31,tplr
tlbpr gr31,gr0,#2,#0 /* save to the TLB */
movsg tpxr,gr31 /* check the TLB write error flag */
andicc.p gr31,#TPXR_E,gr0,icc0
setlos #0xfffff000,gr31
bne icc0,#0,__tlb_user_fault
__itlb_u_nopunt:
# assemble the new TLB entry
and gr28,gr31,gr28
movsg cxnr,gr31
or gr28,gr31,gr28
movgs gr28,iamlr1 /* xAMLR = address | context number */
movgs gr30,iampr1
movgs gr28,damlr1
movgs gr30,dampr1
# return, restoring registers
movsg scr2,gr30
movgs gr30,ccr
rett #0
beq icc0,#3,0 /* prevent icache prefetch */
# the PTE we want wasn't in the PTD we have mapped, so we need to go looking for a more
# appropriate page table and map that instead
# - access the PGD with EAR0[31:26]
# - DAMLR3 points to the virtual address of the page directory
# - the PGD holds 64 PGEs and each PGE/PME points to a set of page tables
__itlb_u_PTD_miss:
srli gr28,#26,gr31 /* calculate PGE offset */
slli gr31,#8,gr31 /* and clear bottom bits */
movsg damlr3,gr30
ld @(gr31,gr30),gr30 /* access the PGE */
andicc.p gr30,#_PAGE_PRESENT,gr0,icc0
andicc gr30,#xAMPRx_SS,gr0,icc1
# map this PTD instead and record coverage address
ori.p gr30,#xAMPRx_L|xAMPRx_SS_16Kb|xAMPRx_S|xAMPRx_C|xAMPRx_V,gr30
beq icc0,#0,__tlb_user_fault /* jump if PGE not present */
slli.p gr31,#18,gr31
bne icc1,#0,__itlb_u_bigpage
movgs gr30,dampr4
movgs gr31,scr0
# we can now resume normal service
setlos 0x3ffc,gr30
srli.p gr28,#12,gr31 /* use EAR0[25:14] as PTE index */
bra __itlb_u_PTD_mapped
__itlb_u_bigpage:
break
nop
.size __entry_user_insn_tlb_miss, .-__entry_user_insn_tlb_miss
###############################################################################
#
# Userspace data TLB miss handler
# On entry:
# GR28 - faulting address
# GR31 - EAR0 ^ SCR1
# SCR1 - base of virtual range covered by cached PGE from last DTLB miss (or 0xffffffff)
# DAMR3 - mapped page directory
# DAMR5 - mapped page table as matched by SCR1
#
###############################################################################
.globl __entry_user_data_tlb_miss
.type __entry_user_data_tlb_miss,@function
__entry_user_data_tlb_miss:
#if 0
sethi.p %hi(0xe1200004),gr30
setlo %lo(0xe1200004),gr30
st gr0,@(gr30,gr0)
sethi.p %hi(0xffc00100),gr30
setlo %lo(0xffc00100),gr30
sth gr30,@(gr30,gr0)
membar
#endif
movsg ccr,gr30 /* save CCR */
movgs gr30,scr2
# see if the cached page table mapping is appropriate
srlicc.p gr31,#26,gr0,icc0
setlos 0x3ffc,gr30
srli.p gr28,#12,gr31 /* use EAR0[25:14] as PTE index */
bne icc0,#0,__dtlb_u_PTD_miss
__dtlb_u_PTD_mapped:
# access the PTD with EAR0[25:14]
# - DAMLR5 points to the virtual address of the appropriate page table
# - the PTD holds 4096 PTEs
# - the PTD must be accessed uncached
# - the PTE must be marked accessed if it was valid
#
and gr31,gr30,gr31
movsg damlr5,gr30
__dtlb_u_using_iPTD:
add gr30,gr31,gr31
ldi @(gr31,#0),gr30 /* fetch the PTE */
andicc gr30,#_PAGE_PRESENT,gr0,icc0
ori.p gr30,#_PAGE_ACCESSED,gr30
beq icc0,#0,__tlb_user_fault /* jump if PTE invalid */
sti.p gr30,@(gr31,#0) /* update the PTE */
andi gr30,#~_PAGE_ACCESSED,gr30
# we're using DAMR1 as an extra TLB entry
# - punt the entry here (if valid) to the real TLB and then replace with the new PTE
movsg dampr1,gr31
andicc gr31,#xAMPRx_V,gr0,icc0
setlos.p 0xfffff000,gr31
beq icc0,#0,__dtlb_u_nopunt /* punt not required */
movsg dampr1,gr31
movgs gr31,tppr
movsg damlr1,gr31 /* set TPLR.CXN */
movgs gr31,tplr
tlbpr gr31,gr0,#2,#0 /* save to the TLB */
movsg tpxr,gr31 /* check the TLB write error flag */
andicc.p gr31,#TPXR_E,gr0,icc0
setlos #0xfffff000,gr31
bne icc0,#0,__tlb_user_fault
__dtlb_u_nopunt:
# assemble the new TLB entry
and gr28,gr31,gr28
movsg cxnr,gr31
or gr28,gr31,gr28
movgs gr28,iamlr1 /* xAMLR = address | context number */
movgs gr30,iampr1
movgs gr28,damlr1
movgs gr30,dampr1
# return, restoring registers
movsg scr2,gr30
movgs gr30,ccr
rett #0
beq icc0,#3,0 /* prevent icache prefetch */
# the PTE we want wasn't in the PTD we have mapped, so we need to go looking for a more
# appropriate page table and map that instead
# - first of all, check the insn PGE cache - we may well get a hit there
# - access the PGD with EAR0[31:26]
# - DAMLR3 points to the virtual address of the page directory
# - the PGD holds 64 PGEs and each PGE/PME points to a set of page tables
__dtlb_u_PTD_miss:
movsg scr0,gr31 /* consult the insn-PGE-cache key */
xor gr28,gr31,gr31
srlicc gr31,#26,gr0,icc0
srli gr28,#12,gr31 /* use EAR0[25:14] as PTE index */
bne icc0,#0,__dtlb_u_iPGE_miss
# what we're looking for is covered by the insn-PGE-cache
setlos 0x3ffc,gr30
and gr31,gr30,gr31
movsg damlr4,gr30
bra __dtlb_u_using_iPTD
__dtlb_u_iPGE_miss:
srli gr28,#26,gr31 /* calculate PGE offset */
slli gr31,#8,gr31 /* and clear bottom bits */
movsg damlr3,gr30
ld @(gr31,gr30),gr30 /* access the PGE */
andicc.p gr30,#_PAGE_PRESENT,gr0,icc0
andicc gr30,#xAMPRx_SS,gr0,icc1
# map this PTD instead and record coverage address
ori.p gr30,#xAMPRx_L|xAMPRx_SS_16Kb|xAMPRx_S|xAMPRx_C|xAMPRx_V,gr30
beq icc0,#0,__tlb_user_fault /* jump if PGE not present */
slli.p gr31,#18,gr31
bne icc1,#0,__dtlb_u_bigpage
movgs gr30,dampr5
movgs gr31,scr1
# we can now resume normal service
setlos 0x3ffc,gr30
srli.p gr28,#12,gr31 /* use EAR0[25:14] as PTE index */
bra __dtlb_u_PTD_mapped
__dtlb_u_bigpage:
break
nop
.size __entry_user_data_tlb_miss, .-__entry_user_data_tlb_miss
