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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /arch/frv/mm/tlb-miss.S
downloadconfigs-2.6.12-rc2.tar.gz
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
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diff --git a/arch/frv/mm/tlb-miss.S b/arch/frv/mm/tlb-miss.S
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+/* 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/config.h>
+#include <linux/linkage.h>
+#include <asm/page.h>
+#include <asm/pgtable.h>
+#include <asm/highmem.h>
+#include <asm/spr-regs.h>
+
+ .section .text
+ .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