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linux/arch/powerpc/mm/tlb_low_64e.S
Scott Wood f67f4ef5fc powerpc/book3e-64: use a separate TLB handler when linear map is bolted 
On MMUs such as FSL where we can guarantee the entire linear mapping is
bolted, we don't need to worry about linear TLB misses.  If on top of
that we do a full table walk, we get rid of all recursive TLB faults, and
can dispense with some state saving.  This gains a few percent on
TLB-miss-heavy workloads, and around 50% on a benchmark that had a high
rate of virtual page table faults under the normal handler.

While touching the EX_TLB layout, remove EX_TLB_MMUCR0, EX_TLB_SRR0, and
EX_TLB_SRR1 as they're not used.

[BenH: Fixed build with 64K pages (wsp config)]

Signed-off-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2011-06-29 17:47:48 +10:00

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/*
* Low level 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 a bolted linear mapping *
* No virtual page table, no nested TLB misses *
* *
**********************************************************************/
.macro tlb_prolog_bolted addr
mtspr SPRN_SPRG_TLB_SCRATCH,r13
mfspr r13,SPRN_SPRG_PACA
std r10,PACA_EXTLB+EX_TLB_R10(r13)
mfcr r10
std r11,PACA_EXTLB+EX_TLB_R11(r13)
std r16,PACA_EXTLB+EX_TLB_R16(r13)
mfspr r16,\addr /* get faulting address */
std r14,PACA_EXTLB+EX_TLB_R14(r13)
ld r14,PACAPGD(r13)
std r15,PACA_EXTLB+EX_TLB_R15(r13)
std r10,PACA_EXTLB+EX_TLB_CR(r13)
TLB_MISS_PROLOG_STATS_BOLTED
.endm
.macro tlb_epilog_bolted
ld r14,PACA_EXTLB+EX_TLB_CR(r13)
ld r10,PACA_EXTLB+EX_TLB_R10(r13)
ld r11,PACA_EXTLB+EX_TLB_R11(r13)
mtcr r14
ld r14,PACA_EXTLB+EX_TLB_R14(r13)
ld r15,PACA_EXTLB+EX_TLB_R15(r13)
TLB_MISS_RESTORE_STATS_BOLTED
ld r16,PACA_EXTLB+EX_TLB_R16(r13)
mfspr r13,SPRN_SPRG_TLB_SCRATCH
.endm
/* Data TLB miss */
START_EXCEPTION(data_tlb_miss_bolted)
tlb_prolog_bolted SPRN_DEAR
/* We need _PAGE_PRESENT and _PAGE_ACCESSED set */
/* We do the user/kernel test for the PID here along with the RW test
*/
/* 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
*/
mfspr r11,SPRN_ESR
srdi r15,r16,60 /* get region */
rldicl. r10,r16,64-PGTABLE_EADDR_SIZE,PGTABLE_EADDR_SIZE+4
bne- dtlb_miss_fault_bolted
rlwinm r10,r11,32-19,27,27
rlwimi r10,r11,32-16,19,19
cmpwi r15,0
ori r10,r10,_PAGE_PRESENT
oris r11,r10,_PAGE_ACCESSED@h
TLB_MISS_STATS_SAVE_INFO_BOLTED
bne tlb_miss_kernel_bolted
tlb_miss_common_bolted:
/*
* This is the guts of the TLB miss handler for bolted-linear.
* We are entered with:
*
* r16 = faulting address
* r15 = crap (free to use)
* r14 = page table base
* r13 = PACA
* r11 = PTE permission mask
* r10 = crap (free to use)
*/
rldicl r15,r16,64-PGDIR_SHIFT+3,64-PGD_INDEX_SIZE-3
cmpldi cr0,r14,0
clrrdi r15,r15,3
beq tlb_miss_fault_bolted
BEGIN_MMU_FTR_SECTION
/* Set the TLB reservation and search for existing entry. Then load
* the entry.
*/
PPC_TLBSRX_DOT(0,r16)
ldx r14,r14,r15
beq normal_tlb_miss_done
MMU_FTR_SECTION_ELSE
ldx r14,r14,r15
ALT_MMU_FTR_SECTION_END_IFSET(MMU_FTR_USE_TLBRSRV)
#ifndef CONFIG_PPC_64K_PAGES
rldicl r15,r16,64-PUD_SHIFT+3,64-PUD_INDEX_SIZE-3
clrrdi r15,r15,3
cmpldi cr0,r14,0
beq tlb_miss_fault_bolted
ldx r14,r14,r15
#endif /* CONFIG_PPC_64K_PAGES */
rldicl r15,r16,64-PMD_SHIFT+3,64-PMD_INDEX_SIZE-3
clrrdi r15,r15,3
cmpldi cr0,r14,0
beq tlb_miss_fault_bolted
ldx r14,r14,r15
rldicl r15,r16,64-PAGE_SHIFT+3,64-PTE_INDEX_SIZE-3
clrrdi r15,r15,3
cmpldi cr0,r14,0
beq tlb_miss_fault_bolted
ldx r14,r14,r15
/* Check if required permissions are met */
andc. r15,r11,r14
rldicr r15,r14,64-(PTE_RPN_SHIFT-PAGE_SHIFT),63-PAGE_SHIFT
bne- tlb_miss_fault_bolted
/* 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
*/
clrrdi r11,r16,12 /* Clear low crap in EA */
clrldi r15,r15,12 /* Clear crap at the top */
rlwimi r11,r14,32-19,27,31 /* Insert WIMGE */
rlwimi r15,r14,32-8,22,25 /* Move in U bits */
mtspr SPRN_MAS2,r11
andi. r11,r14,_PAGE_DIRTY
rlwimi r15,r14,32-2,26,31 /* Move in BAP bits */
/* Mask out SW and UW if !DIRTY (XXX optimize this !) */
bne 1f
li r11,MAS3_SW|MAS3_UW
andc r15,r15,r11
1:
mtspr SPRN_MAS7_MAS3,r15
tlbwe
TLB_MISS_STATS_X(MMSTAT_TLB_MISS_NORM_OK)
tlb_epilog_bolted
rfi
itlb_miss_kernel_bolted:
li r11,_PAGE_PRESENT|_PAGE_BAP_SX /* Base perm */
oris r11,r11,_PAGE_ACCESSED@h
tlb_miss_kernel_bolted:
mfspr r10,SPRN_MAS1
ld r14,PACA_KERNELPGD(r13)
cmpldi cr0,r15,8 /* Check for vmalloc region */
rlwinm r10,r10,0,16,1 /* Clear TID */
mtspr SPRN_MAS1,r10
beq+ tlb_miss_common_bolted
tlb_miss_fault_bolted:
/* We need to check if it was an instruction miss */
andi. r10,r11,_PAGE_EXEC|_PAGE_BAP_SX
bne itlb_miss_fault_bolted
dtlb_miss_fault_bolted:
TLB_MISS_STATS_D(MMSTAT_TLB_MISS_NORM_FAULT)
tlb_epilog_bolted
b exc_data_storage_book3e
itlb_miss_fault_bolted:
TLB_MISS_STATS_I(MMSTAT_TLB_MISS_NORM_FAULT)
tlb_epilog_bolted
b exc_instruction_storage_book3e
/* Instruction TLB miss */
START_EXCEPTION(instruction_tlb_miss_bolted)
tlb_prolog_bolted SPRN_SRR0
rldicl. r10,r16,64-PGTABLE_EADDR_SIZE,PGTABLE_EADDR_SIZE+4
srdi r15,r16,60 /* get region */
TLB_MISS_STATS_SAVE_INFO_BOLTED
bne- itlb_miss_fault_bolted
li r11,_PAGE_PRESENT|_PAGE_EXEC /* Base perm */
/* We do the user/kernel test for the PID here along with the RW test
*/
cmpldi cr0,r15,0 /* Check for user region */
oris r11,r11,_PAGE_ACCESSED@h
beq tlb_miss_common_bolted
b itlb_miss_kernel_bolted
/**********************************************************************
* *
* 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
li r11,_PAGE_PRESENT|_PAGE_BAP_SX /* Base perm */
oris r11,r11,_PAGE_ACCESSED@h
/* XXX replace the RMW cycles with immediate loads + writes */
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 search 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 retrieve
* 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 information 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
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