Linux-2.6.33.2/arch/powerpc/mm/tlb_low_64e.S
/*
* Low leve TLB miss handlers for Book3E
*
* Copyright (C) 2008-2009
* Ben. Herrenschmidt (benh@kernel.crashing.org), IBM Corp.
*
* 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 <asm/processor.h>
#include <asm/reg.h>
#include <asm/page.h>
#include <asm/mmu.h>
#include <asm/ppc_asm.h>
#include <asm/asm-offsets.h>
#include <asm/cputable.h>
#include <asm/pgtable.h>
#include <asm/exception-64e.h>
#include <asm/ppc-opcode.h>
#ifdef CONFIG_PPC_64K_PAGES
#define VPTE_PMD_SHIFT (PTE_INDEX_SIZE+1)
#else
#define VPTE_PMD_SHIFT (PTE_INDEX_SIZE)
#endif
#define VPTE_PUD_SHIFT (VPTE_PMD_SHIFT + PMD_INDEX_SIZE)
#define VPTE_PGD_SHIFT (VPTE_PUD_SHIFT + PUD_INDEX_SIZE)
#define VPTE_INDEX_SIZE (VPTE_PGD_SHIFT + PGD_INDEX_SIZE)
/**********************************************************************
* *
* TLB miss handling for Book3E with TLB reservation and HES support *
* *
**********************************************************************/
/* Data TLB miss */
START_EXCEPTION(data_tlb_miss)
TLB_MISS_PROLOG
/* Now we handle the fault proper. We only save DEAR in normal
* fault case since that's the only interesting values here.
* We could probably also optimize by not saving SRR0/1 in the
* linear mapping case but I'll leave that for later
*/
mfspr r14,SPRN_ESR
mfspr r16,SPRN_DEAR /* get faulting address */
srdi r15,r16,60 /* get region */
cmpldi cr0,r15,0xc /* linear mapping ? */
TLB_MISS_STATS_SAVE_INFO
beq tlb_load_linear /* yes -> go to linear map load */
/* The page tables are mapped virtually linear. At this point, though,
* we don't know whether we are trying to fault in a first level
* virtual address or a virtual page table address. We can get that
* from bit 0x1 of the region ID which we have set for a page table
*/
andi. r10,r15,0x1
bne- virt_page_table_tlb_miss
std r14,EX_TLB_ESR(r12); /* save ESR */
std r16,EX_TLB_DEAR(r12); /* save DEAR */
/* We need _PAGE_PRESENT and _PAGE_ACCESSED set */
li r11,_PAGE_PRESENT
oris r11,r11,_PAGE_ACCESSED@h
/* We do the user/kernel test for the PID here along with the RW test
*/
cmpldi cr0,r15,0 /* Check for user region */
/* We pre-test some combination of permissions to avoid double
* faults:
*
* We move the ESR:ST bit into the position of _PAGE_BAP_SW in the PTE
* ESR_ST is 0x00800000
* _PAGE_BAP_SW is 0x00000010
* So the shift is >> 19. This tests for supervisor writeability.
* If the page happens to be supervisor writeable and not user
* writeable, we will take a new fault later, but that should be
* a rare enough case.
*
* We also move ESR_ST in _PAGE_DIRTY position
* _PAGE_DIRTY is 0x00001000 so the shift is >> 11
*
* MAS1 is preset for all we need except for TID that needs to
* be cleared for kernel translations
*/
rlwimi r11,r14,32-19,27,27
rlwimi r11,r14,32-16,19,19
beq normal_tlb_miss
/* XXX replace the RMW cycles with immediate loads + writes */
1: mfspr r10,SPRN_MAS1
cmpldi cr0,r15,8 /* Check for vmalloc region */
rlwinm r10,r10,0,16,1 /* Clear TID */
mtspr SPRN_MAS1,r10
beq+ normal_tlb_miss
/* We got a crappy address, just fault with whatever DEAR and ESR
* are here
*/
TLB_MISS_STATS_D(MMSTAT_TLB_MISS_NORM_FAULT)
TLB_MISS_EPILOG_ERROR
b exc_data_storage_book3e
/* Instruction TLB miss */
START_EXCEPTION(instruction_tlb_miss)
TLB_MISS_PROLOG
/* If we take a recursive fault, the second level handler may need
* to know whether we are handling a data or instruction fault in
* order to get to the right store fault handler. We provide that
* info by writing a crazy value in ESR in our exception frame
*/
li r14,-1 /* store to exception frame is done later */
/* Now we handle the fault proper. We only save DEAR in the non
* linear mapping case since we know the linear mapping case will
* not re-enter. We could indeed optimize and also not save SRR0/1
* in the linear mapping case but I'll leave that for later
*
* Faulting address is SRR0 which is already in r16
*/
srdi r15,r16,60 /* get region */
cmpldi cr0,r15,0xc /* linear mapping ? */
TLB_MISS_STATS_SAVE_INFO
beq tlb_load_linear /* yes -> go to linear map load */
/* We do the user/kernel test for the PID here along with the RW test
*/
li r11,_PAGE_PRESENT|_PAGE_EXEC /* Base perm */
oris r11,r11,_PAGE_ACCESSED@h
cmpldi cr0,r15,0 /* Check for user region */
std r14,EX_TLB_ESR(r12) /* write crazy -1 to frame */
beq normal_tlb_miss
/* XXX replace the RMW cycles with immediate loads + writes */
1: mfspr r10,SPRN_MAS1
cmpldi cr0,r15,8 /* Check for vmalloc region */
rlwinm r10,r10,0,16,1 /* Clear TID */
mtspr SPRN_MAS1,r10
beq+ normal_tlb_miss
/* We got a crappy address, just fault */
TLB_MISS_STATS_I(MMSTAT_TLB_MISS_NORM_FAULT)
TLB_MISS_EPILOG_ERROR
b exc_instruction_storage_book3e
/*
* This is the guts of the first-level TLB miss handler for direct
* misses. We are entered with:
*
* r16 = faulting address
* r15 = region ID
* r14 = crap (free to use)
* r13 = PACA
* r12 = TLB exception frame in PACA
* r11 = PTE permission mask
* r10 = crap (free to use)
*/
normal_tlb_miss:
/* So we first construct the page table address. We do that by
* shifting the bottom of the address (not the region ID) by
* PAGE_SHIFT-3, clearing the bottom 3 bits (get a PTE ptr) and
* or'ing the fourth high bit.
*
* NOTE: For 64K pages, we do things slightly differently in
* order to handle the weird page table format used by linux
*/
ori r10,r15,0x1
#ifdef CONFIG_PPC_64K_PAGES
/* For the top bits, 16 bytes per PTE */
rldicl r14,r16,64-(PAGE_SHIFT-4),PAGE_SHIFT-4+4
/* Now create the bottom bits as 0 in position 0x8000 and
* the rest calculated for 8 bytes per PTE
*/
rldicl r15,r16,64-(PAGE_SHIFT-3),64-15
/* Insert the bottom bits in */
rlwimi r14,r15,0,16,31
#else
rldicl r14,r16,64-(PAGE_SHIFT-3),PAGE_SHIFT-3+4
#endif
sldi r15,r10,60
clrrdi r14,r14,3
or r10,r15,r14
BEGIN_MMU_FTR_SECTION
/* Set the TLB reservation and seach for existing entry. Then load
* the entry.
*/
PPC_TLBSRX_DOT(0,r16)
ld r14,0(r10)
beq normal_tlb_miss_done
MMU_FTR_SECTION_ELSE
ld r14,0(r10)
ALT_MMU_FTR_SECTION_END_IFSET(MMU_FTR_USE_TLBRSRV)
finish_normal_tlb_miss:
/* Check if required permissions are met */
andc. r15,r11,r14
bne- normal_tlb_miss_access_fault
/* Now we build the MAS:
*
* MAS 0 : Fully setup with defaults in MAS4 and TLBnCFG
* MAS 1 : Almost fully setup
* - PID already updated by caller if necessary
* - TSIZE need change if !base page size, not
* yet implemented for now
* MAS 2 : Defaults not useful, need to be redone
* MAS 3+7 : Needs to be done
*
* TODO: mix up code below for better scheduling
*/
clrrdi r11,r16,12 /* Clear low crap in EA */
rlwimi r11,r14,32-19,27,31 /* Insert WIMGE */
mtspr SPRN_MAS2,r11
/* Check page size, if not standard, update MAS1 */
rldicl r11,r14,64-8,64-8
#ifdef CONFIG_PPC_64K_PAGES
cmpldi cr0,r11,BOOK3E_PAGESZ_64K
#else
cmpldi cr0,r11,BOOK3E_PAGESZ_4K
#endif
beq- 1f
mfspr r11,SPRN_MAS1
rlwimi r11,r14,31,21,24
rlwinm r11,r11,0,21,19
mtspr SPRN_MAS1,r11
1:
/* Move RPN in position */
rldicr r11,r14,64-(PTE_RPN_SHIFT-PAGE_SHIFT),63-PAGE_SHIFT
clrldi r15,r11,12 /* Clear crap at the top */
rlwimi r15,r14,32-8,22,25 /* Move in U bits */
rlwimi r15,r14,32-2,26,31 /* Move in BAP bits */
/* Mask out SW and UW if !DIRTY (XXX optimize this !) */
andi. r11,r14,_PAGE_DIRTY
bne 1f
li r11,MAS3_SW|MAS3_UW
andc r15,r15,r11
1:
BEGIN_MMU_FTR_SECTION
srdi r16,r15,32
mtspr SPRN_MAS3,r15
mtspr SPRN_MAS7,r16
MMU_FTR_SECTION_ELSE
mtspr SPRN_MAS7_MAS3,r15
ALT_MMU_FTR_SECTION_END_IFCLR(MMU_FTR_USE_PAIRED_MAS)
tlbwe
normal_tlb_miss_done:
/* We don't bother with restoring DEAR or ESR since we know we are
* level 0 and just going back to userland. They are only needed
* if you are going to take an access fault
*/
TLB_MISS_STATS_X(MMSTAT_TLB_MISS_NORM_OK)
TLB_MISS_EPILOG_SUCCESS
rfi
normal_tlb_miss_access_fault:
/* We need to check if it was an instruction miss */
andi. r10,r11,_PAGE_EXEC
bne 1f
ld r14,EX_TLB_DEAR(r12)
ld r15,EX_TLB_ESR(r12)
mtspr SPRN_DEAR,r14
mtspr SPRN_ESR,r15
TLB_MISS_STATS_D(MMSTAT_TLB_MISS_NORM_FAULT)
TLB_MISS_EPILOG_ERROR
b exc_data_storage_book3e
1: TLB_MISS_STATS_I(MMSTAT_TLB_MISS_NORM_FAULT)
TLB_MISS_EPILOG_ERROR
b exc_instruction_storage_book3e
/*
* This is the guts of the second-level TLB miss handler for direct
* misses. We are entered with:
*
* r16 = virtual page table faulting address
* r15 = region (top 4 bits of address)
* r14 = crap (free to use)
* r13 = PACA
* r12 = TLB exception frame in PACA
* r11 = crap (free to use)
* r10 = crap (free to use)
*
* Note that this should only ever be called as a second level handler
* with the current scheme when using SW load.
* That means we can always get the original fault DEAR at
* EX_TLB_DEAR-EX_TLB_SIZE(r12)
*
* It can be re-entered by the linear mapping miss handler. However, to
* avoid too much complication, it will restart the whole fault at level
* 0 so we don't care too much about clobbers
*
* XXX That code was written back when we couldn't clobber r14. We can now,
* so we could probably optimize things a bit
*/
virt_page_table_tlb_miss:
/* Are we hitting a kernel page table ? */
andi. r10,r15,0x8
/* The cool thing now is that r10 contains 0 for user and 8 for kernel,
* and we happen to have the swapper_pg_dir at offset 8 from the user
* pgdir in the PACA :-).
*/
add r11,r10,r13
/* If kernel, we need to clear MAS1 TID */
beq 1f
/* XXX replace the RMW cycles with immediate loads + writes */
mfspr r10,SPRN_MAS1
rlwinm r10,r10,0,16,1 /* Clear TID */
mtspr SPRN_MAS1,r10
1:
BEGIN_MMU_FTR_SECTION
/* Search if we already have a TLB entry for that virtual address, and
* if we do, bail out.
*/
PPC_TLBSRX_DOT(0,r16)
beq virt_page_table_tlb_miss_done
END_MMU_FTR_SECTION_IFSET(MMU_FTR_USE_TLBRSRV)
/* Now, we need to walk the page tables. First check if we are in
* range.
*/
rldicl. r10,r16,64-(VPTE_INDEX_SIZE+3),VPTE_INDEX_SIZE+3+4
bne- virt_page_table_tlb_miss_fault
/* Get the PGD pointer */
ld r15,PACAPGD(r11)
cmpldi cr0,r15,0
beq- virt_page_table_tlb_miss_fault
/* Get to PGD entry */
rldicl r11,r16,64-VPTE_PGD_SHIFT,64-PGD_INDEX_SIZE-3
clrrdi r10,r11,3
ldx r15,r10,r15
cmpldi cr0,r15,0
beq virt_page_table_tlb_miss_fault
#ifndef CONFIG_PPC_64K_PAGES
/* Get to PUD entry */
rldicl r11,r16,64-VPTE_PUD_SHIFT,64-PUD_INDEX_SIZE-3
clrrdi r10,r11,3
ldx r15,r10,r15
cmpldi cr0,r15,0
beq virt_page_table_tlb_miss_fault
#endif /* CONFIG_PPC_64K_PAGES */
/* Get to PMD entry */
rldicl r11,r16,64-VPTE_PMD_SHIFT,64-PMD_INDEX_SIZE-3
clrrdi r10,r11,3
ldx r15,r10,r15
cmpldi cr0,r15,0
beq virt_page_table_tlb_miss_fault
/* Ok, we're all right, we can now create a kernel translation for
* a 4K or 64K page from r16 -> r15.
*/
/* Now we build the MAS:
*
* MAS 0 : Fully setup with defaults in MAS4 and TLBnCFG
* MAS 1 : Almost fully setup
* - PID already updated by caller if necessary
* - TSIZE for now is base page size always
* MAS 2 : Use defaults
* MAS 3+7 : Needs to be done
*
* So we only do MAS 2 and 3 for now...
*/
clrldi r11,r15,4 /* remove region ID from RPN */
ori r10,r11,1 /* Or-in SR */
BEGIN_MMU_FTR_SECTION
srdi r16,r10,32
mtspr SPRN_MAS3,r10
mtspr SPRN_MAS7,r16
MMU_FTR_SECTION_ELSE
mtspr SPRN_MAS7_MAS3,r10
ALT_MMU_FTR_SECTION_END_IFCLR(MMU_FTR_USE_PAIRED_MAS)
tlbwe
BEGIN_MMU_FTR_SECTION
virt_page_table_tlb_miss_done:
/* We have overriden MAS2:EPN but currently our primary TLB miss
* handler will always restore it so that should not be an issue,
* if we ever optimize the primary handler to not write MAS2 on
* some cases, we'll have to restore MAS2:EPN here based on the
* original fault's DEAR. If we do that we have to modify the
* ITLB miss handler to also store SRR0 in the exception frame
* as DEAR.
*
* However, one nasty thing we did is we cleared the reservation
* (well, potentially we did). We do a trick here thus if we
* are not a level 0 exception (we interrupted the TLB miss) we
* offset the return address by -4 in order to replay the tlbsrx
* instruction there
*/
subf r10,r13,r12
cmpldi cr0,r10,PACA_EXTLB+EX_TLB_SIZE
bne- 1f
ld r11,PACA_EXTLB+EX_TLB_SIZE+EX_TLB_SRR0(r13)
addi r10,r11,-4
std r10,PACA_EXTLB+EX_TLB_SIZE+EX_TLB_SRR0(r13)
1:
END_MMU_FTR_SECTION_IFSET(MMU_FTR_USE_TLBRSRV)
/* Return to caller, normal case */
TLB_MISS_STATS_X(MMSTAT_TLB_MISS_PT_OK);
TLB_MISS_EPILOG_SUCCESS
rfi
virt_page_table_tlb_miss_fault:
/* If we fault here, things are a little bit tricky. We need to call
* either data or instruction store fault, and we need to retreive
* the original fault address and ESR (for data).
*
* The thing is, we know that in normal circumstances, this is
* always called as a second level tlb miss for SW load or as a first
* level TLB miss for HW load, so we should be able to peek at the
* relevant informations in the first exception frame in the PACA.
*
* However, we do need to double check that, because we may just hit
* a stray kernel pointer or a userland attack trying to hit those
* areas. If that is the case, we do a data fault. (We can't get here
* from an instruction tlb miss anyway).
*
* Note also that when going to a fault, we must unwind the previous
* level as well. Since we are doing that, we don't need to clear or
* restore the TLB reservation neither.
*/
subf r10,r13,r12
cmpldi cr0,r10,PACA_EXTLB+EX_TLB_SIZE
bne- virt_page_table_tlb_miss_whacko_fault
/* We dig the original DEAR and ESR from slot 0 */
ld r15,EX_TLB_DEAR+PACA_EXTLB(r13)
ld r16,EX_TLB_ESR+PACA_EXTLB(r13)
/* We check for the "special" ESR value for instruction faults */
cmpdi cr0,r16,-1
beq 1f
mtspr SPRN_DEAR,r15
mtspr SPRN_ESR,r16
TLB_MISS_STATS_D(MMSTAT_TLB_MISS_PT_FAULT);
TLB_MISS_EPILOG_ERROR
b exc_data_storage_book3e
1: TLB_MISS_STATS_I(MMSTAT_TLB_MISS_PT_FAULT);
TLB_MISS_EPILOG_ERROR
b exc_instruction_storage_book3e
virt_page_table_tlb_miss_whacko_fault:
/* The linear fault will restart everything so ESR and DEAR will
* not have been clobbered, let's just fault with what we have
*/
TLB_MISS_STATS_X(MMSTAT_TLB_MISS_PT_FAULT);
TLB_MISS_EPILOG_ERROR
b exc_data_storage_book3e
/**************************************************************
* *
* TLB miss handling for Book3E with hw page table support *
* *
**************************************************************/
/* Data TLB miss */
START_EXCEPTION(data_tlb_miss_htw)
TLB_MISS_PROLOG
/* Now we handle the fault proper. We only save DEAR in normal
* fault case since that's the only interesting values here.
* We could probably also optimize by not saving SRR0/1 in the
* linear mapping case but I'll leave that for later
*/
mfspr r14,SPRN_ESR
mfspr r16,SPRN_DEAR /* get faulting address */
srdi r11,r16,60 /* get region */
cmpldi cr0,r11,0xc /* linear mapping ? */
TLB_MISS_STATS_SAVE_INFO
beq tlb_load_linear /* yes -> go to linear map load */
/* We do the user/kernel test for the PID here along with the RW test
*/
cmpldi cr0,r11,0 /* Check for user region */
ld r15,PACAPGD(r13) /* Load user pgdir */
beq htw_tlb_miss
/* XXX replace the RMW cycles with immediate loads + writes */
1: mfspr r10,SPRN_MAS1
cmpldi cr0,r11,8 /* Check for vmalloc region */
rlwinm r10,r10,0,16,1 /* Clear TID */
mtspr SPRN_MAS1,r10
ld r15,PACA_KERNELPGD(r13) /* Load kernel pgdir */
beq+ htw_tlb_miss
/* We got a crappy address, just fault with whatever DEAR and ESR
* are here
*/
TLB_MISS_STATS_D(MMSTAT_TLB_MISS_NORM_FAULT)
TLB_MISS_EPILOG_ERROR
b exc_data_storage_book3e
/* Instruction TLB miss */
START_EXCEPTION(instruction_tlb_miss_htw)
TLB_MISS_PROLOG
/* If we take a recursive fault, the second level handler may need
* to know whether we are handling a data or instruction fault in
* order to get to the right store fault handler. We provide that
* info by keeping a crazy value for ESR in r14
*/
li r14,-1 /* store to exception frame is done later */
/* Now we handle the fault proper. We only save DEAR in the non
* linear mapping case since we know the linear mapping case will
* not re-enter. We could indeed optimize and also not save SRR0/1
* in the linear mapping case but I'll leave that for later
*
* Faulting address is SRR0 which is already in r16
*/
srdi r11,r16,60 /* get region */
cmpldi cr0,r11,0xc /* linear mapping ? */
TLB_MISS_STATS_SAVE_INFO
beq tlb_load_linear /* yes -> go to linear map load */
/* We do the user/kernel test for the PID here along with the RW test
*/
cmpldi cr0,r11,0 /* Check for user region */
ld r15,PACAPGD(r13) /* Load user pgdir */
beq htw_tlb_miss
/* XXX replace the RMW cycles with immediate loads + writes */
1: mfspr r10,SPRN_MAS1
cmpldi cr0,r11,8 /* Check for vmalloc region */
rlwinm r10,r10,0,16,1 /* Clear TID */
mtspr SPRN_MAS1,r10
ld r15,PACA_KERNELPGD(r13) /* Load kernel pgdir */
beq+ htw_tlb_miss
/* We got a crappy address, just fault */
TLB_MISS_STATS_I(MMSTAT_TLB_MISS_NORM_FAULT)
TLB_MISS_EPILOG_ERROR
b exc_instruction_storage_book3e
/*
* This is the guts of the second-level TLB miss handler for direct
* misses. We are entered with:
*
* r16 = virtual page table faulting address
* r15 = PGD pointer
* r14 = ESR
* r13 = PACA
* r12 = TLB exception frame in PACA
* r11 = crap (free to use)
* r10 = crap (free to use)
*
* It can be re-entered by the linear mapping miss handler. However, to
* avoid too much complication, it will save/restore things for us
*/
htw_tlb_miss:
/* Search if we already have a TLB entry for that virtual address, and
* if we do, bail out.
*
* MAS1:IND should be already set based on MAS4
*/
PPC_TLBSRX_DOT(0,r16)
beq htw_tlb_miss_done
/* Now, we need to walk the page tables. First check if we are in
* range.
*/
rldicl. r10,r16,64-PGTABLE_EADDR_SIZE,PGTABLE_EADDR_SIZE+4
bne- htw_tlb_miss_fault
/* Get the PGD pointer */
cmpldi cr0,r15,0
beq- htw_tlb_miss_fault
/* Get to PGD entry */
rldicl r11,r16,64-(PGDIR_SHIFT-3),64-PGD_INDEX_SIZE-3
clrrdi r10,r11,3
ldx r15,r10,r15
cmpldi cr0,r15,0
beq htw_tlb_miss_fault
#ifndef CONFIG_PPC_64K_PAGES
/* Get to PUD entry */
rldicl r11,r16,64-(PUD_SHIFT-3),64-PUD_INDEX_SIZE-3
clrrdi r10,r11,3
ldx r15,r10,r15
cmpldi cr0,r15,0
beq htw_tlb_miss_fault
#endif /* CONFIG_PPC_64K_PAGES */
/* Get to PMD entry */
rldicl r11,r16,64-(PMD_SHIFT-3),64-PMD_INDEX_SIZE-3
clrrdi r10,r11,3
ldx r15,r10,r15
cmpldi cr0,r15,0
beq htw_tlb_miss_fault
/* Ok, we're all right, we can now create an indirect entry for
* a 1M or 256M page.
*
* The last trick is now that because we use "half" pages for
* the HTW (1M IND is 2K and 256M IND is 32K) we need to account
* for an added LSB bit to the RPN. For 64K pages, there is no
* problem as we already use 32K arrays (half PTE pages), but for
* 4K page we need to extract a bit from the virtual address and
* insert it into the "PA52" bit of the RPN.
*/
#ifndef CONFIG_PPC_64K_PAGES
rlwimi r15,r16,32-9,20,20
#endif
/* Now we build the MAS:
*
* MAS 0 : Fully setup with defaults in MAS4 and TLBnCFG
* MAS 1 : Almost fully setup
* - PID already updated by caller if necessary
* - TSIZE for now is base ind page size always
* MAS 2 : Use defaults
* MAS 3+7 : Needs to be done
*/
#ifdef CONFIG_PPC_64K_PAGES
ori r10,r15,(BOOK3E_PAGESZ_64K << MAS3_SPSIZE_SHIFT)
#else
ori r10,r15,(BOOK3E_PAGESZ_4K << MAS3_SPSIZE_SHIFT)
#endif
BEGIN_MMU_FTR_SECTION
srdi r16,r10,32
mtspr SPRN_MAS3,r10
mtspr SPRN_MAS7,r16
MMU_FTR_SECTION_ELSE
mtspr SPRN_MAS7_MAS3,r10
ALT_MMU_FTR_SECTION_END_IFCLR(MMU_FTR_USE_PAIRED_MAS)
tlbwe
htw_tlb_miss_done:
/* We don't bother with restoring DEAR or ESR since we know we are
* level 0 and just going back to userland. They are only needed
* if you are going to take an access fault
*/
TLB_MISS_STATS_X(MMSTAT_TLB_MISS_PT_OK)
TLB_MISS_EPILOG_SUCCESS
rfi
htw_tlb_miss_fault:
/* We need to check if it was an instruction miss. We know this
* though because r14 would contain -1
*/
cmpdi cr0,r14,-1
beq 1f
mtspr SPRN_DEAR,r16
mtspr SPRN_ESR,r14
TLB_MISS_STATS_D(MMSTAT_TLB_MISS_PT_FAULT)
TLB_MISS_EPILOG_ERROR
b exc_data_storage_book3e
1: TLB_MISS_STATS_I(MMSTAT_TLB_MISS_PT_FAULT)
TLB_MISS_EPILOG_ERROR
b exc_instruction_storage_book3e
/*
* This is the guts of "any" level TLB miss handler for kernel linear
* mapping misses. We are entered with:
*
*
* r16 = faulting address
* r15 = crap (free to use)
* r14 = ESR (data) or -1 (instruction)
* r13 = PACA
* r12 = TLB exception frame in PACA
* r11 = crap (free to use)
* r10 = crap (free to use)
*
* In addition we know that we will not re-enter, so in theory, we could
* use a simpler epilog not restoring SRR0/1 etc.. but we'll do that later.
*
* We also need to be careful about MAS registers here & TLB reservation,
* as we know we'll have clobbered them if we interrupt the main TLB miss
* handlers in which case we probably want to do a full restart at level
* 0 rather than saving / restoring the MAS.
*
* Note: If we care about performance of that core, we can easily shuffle
* a few things around
*/
tlb_load_linear:
/* For now, we assume the linear mapping is contiguous and stops at
* linear_map_top. We also assume the size is a multiple of 1G, thus
* we only use 1G pages for now. That might have to be changed in a
* final implementation, especially when dealing with hypervisors
*/
ld r11,PACATOC(r13)
ld r11,linear_map_top@got(r11)
ld r10,0(r11)
cmpld cr0,r10,r16
bge tlb_load_linear_fault
/* MAS1 need whole new setup. */
li r15,(BOOK3E_PAGESZ_1GB<<MAS1_TSIZE_SHIFT)
oris r15,r15,MAS1_VALID@h /* MAS1 needs V and TSIZE */
mtspr SPRN_MAS1,r15
/* Already somebody there ? */
PPC_TLBSRX_DOT(0,r16)
beq tlb_load_linear_done
/* Now we build the remaining MAS. MAS0 and 2 should be fine
* with their defaults, which leaves us with MAS 3 and 7. The
* mapping is linear, so we just take the address, clear the
* region bits, and or in the permission bits which are currently
* hard wired
*/
clrrdi r10,r16,30 /* 1G page index */
clrldi r10,r10,4 /* clear region bits */
ori r10,r10,MAS3_SR|MAS3_SW|MAS3_SX
BEGIN_MMU_FTR_SECTION
srdi r16,r10,32
mtspr SPRN_MAS3,r10
mtspr SPRN_MAS7,r16
MMU_FTR_SECTION_ELSE
mtspr SPRN_MAS7_MAS3,r10
ALT_MMU_FTR_SECTION_END_IFCLR(MMU_FTR_USE_PAIRED_MAS)
tlbwe
tlb_load_linear_done:
/* We use the "error" epilog for success as we do want to
* restore to the initial faulting context, whatever it was.
* We do that because we can't resume a fault within a TLB
* miss handler, due to MAS and TLB reservation being clobbered.
*/
TLB_MISS_STATS_X(MMSTAT_TLB_MISS_LINEAR)
TLB_MISS_EPILOG_ERROR
rfi
tlb_load_linear_fault:
/* We keep the DEAR and ESR around, this shouldn't have happened */
cmpdi cr0,r14,-1
beq 1f
TLB_MISS_EPILOG_ERROR_SPECIAL
b exc_data_storage_book3e
1: TLB_MISS_EPILOG_ERROR_SPECIAL
b exc_instruction_storage_book3e
#ifdef CONFIG_BOOK3E_MMU_TLB_STATS
.tlb_stat_inc:
1: ldarx r8,0,r9
addi r8,r8,1
stdcx. r8,0,r9
bne- 1b
blr
#endif