--- /dev/null
+/*
+ * 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/reg.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_HWEXEC /* 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
+
+ /* 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
+
+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: mtspr SPRN_MAS7_MAS3,r15
+
+ 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_HWEXEC
+ 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:
+ /* 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
+
+ /* 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 */
+ mtspr SPRN_MAS7_MAS3,r10
+
+ tlbwe
+
+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:
+ /* 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
+ mtspr SPRN_MAS7_MAS3,r10
+
+ 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
+ mtspr SPRN_MAS7_MAS3,r10
+
+ 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
*
* -- BenH
*
- * Copyright 2008 Ben Herrenschmidt <benh@kernel.crashing.org>
- * IBM Corp.
+ * Copyright 2008,2009 Ben Herrenschmidt <benh@kernel.crashing.org>
+ * IBM Corp.
*
* Derived from arch/ppc/mm/init.c:
* Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
#include <linux/pagemap.h>
#include <linux/preempt.h>
#include <linux/spinlock.h>
+#include <linux/lmb.h>
#include <asm/tlbflush.h>
#include <asm/tlb.h>
+#include <asm/code-patching.h>
#include "mmu_decl.h"
+#ifdef CONFIG_PPC_BOOK3E
+struct mmu_psize_def mmu_psize_defs[MMU_PAGE_COUNT] = {
+ [MMU_PAGE_4K] = {
+ .shift = 12,
+ .enc = BOOK3E_PAGESZ_4K,
+ },
+ [MMU_PAGE_16K] = {
+ .shift = 14,
+ .enc = BOOK3E_PAGESZ_16K,
+ },
+ [MMU_PAGE_64K] = {
+ .shift = 16,
+ .enc = BOOK3E_PAGESZ_64K,
+ },
+ [MMU_PAGE_1M] = {
+ .shift = 20,
+ .enc = BOOK3E_PAGESZ_1M,
+ },
+ [MMU_PAGE_16M] = {
+ .shift = 24,
+ .enc = BOOK3E_PAGESZ_16M,
+ },
+ [MMU_PAGE_256M] = {
+ .shift = 28,
+ .enc = BOOK3E_PAGESZ_256M,
+ },
+ [MMU_PAGE_1G] = {
+ .shift = 30,
+ .enc = BOOK3E_PAGESZ_1GB,
+ },
+};
+static inline int mmu_get_tsize(int psize)
+{
+ return mmu_psize_defs[psize].enc;
+}
+#else
+static inline int mmu_get_tsize(int psize)
+{
+ /* This isn't used on !Book3E for now */
+ return 0;
+}
+#endif
+
+/* The variables below are currently only used on 64-bit Book3E
+ * though this will probably be made common with other nohash
+ * implementations at some point
+ */
+#ifdef CONFIG_PPC64
+
+int mmu_linear_psize; /* Page size used for the linear mapping */
+int mmu_pte_psize; /* Page size used for PTE pages */
+int book3e_htw_enabled; /* Is HW tablewalk enabled ? */
+unsigned long linear_map_top; /* Top of linear mapping */
+
+#endif /* CONFIG_PPC64 */
+
/*
* Base TLB flushing operations:
*
void local_flush_tlb_page(struct vm_area_struct *vma, unsigned long vmaddr)
{
__local_flush_tlb_page(vma ? vma->vm_mm : NULL, vmaddr,
- 0 /* tsize unused for now */, 0);
+ mmu_get_tsize(mmu_virtual_psize), 0);
}
EXPORT_SYMBOL(local_flush_tlb_page);
void flush_tlb_page(struct vm_area_struct *vma, unsigned long vmaddr)
{
__flush_tlb_page(vma ? vma->vm_mm : NULL, vmaddr,
- 0 /* tsize unused for now */, 0);
+ mmu_get_tsize(mmu_virtual_psize), 0);
}
EXPORT_SYMBOL(flush_tlb_page);
/* Push out batch of freed page tables */
pte_free_finish();
}
+
+/*
+ * Below are functions specific to the 64-bit variant of Book3E though that
+ * may change in the future
+ */
+
+#ifdef CONFIG_PPC64
+
+/*
+ * Handling of virtual linear page tables or indirect TLB entries
+ * flushing when PTE pages are freed
+ */
+void tlb_flush_pgtable(struct mmu_gather *tlb, unsigned long address)
+{
+ int tsize = mmu_psize_defs[mmu_pte_psize].enc;
+
+ if (book3e_htw_enabled) {
+ unsigned long start = address & PMD_MASK;
+ unsigned long end = address + PMD_SIZE;
+ unsigned long size = 1UL << mmu_psize_defs[mmu_pte_psize].shift;
+
+ /* This isn't the most optimal, ideally we would factor out the
+ * while preempt & CPU mask mucking around, or even the IPI but
+ * it will do for now
+ */
+ while (start < end) {
+ __flush_tlb_page(tlb->mm, start, tsize, 1);
+ start += size;
+ }
+ } else {
+ unsigned long rmask = 0xf000000000000000ul;
+ unsigned long rid = (address & rmask) | 0x1000000000000000ul;
+ unsigned long vpte = address & ~rmask;
+
+#ifdef CONFIG_PPC_64K_PAGES
+ vpte = (vpte >> (PAGE_SHIFT - 4)) & ~0xfffful;
+#else
+ vpte = (vpte >> (PAGE_SHIFT - 3)) & ~0xffful;
+#endif
+ vpte |= rid;
+ __flush_tlb_page(tlb->mm, vpte, tsize, 0);
+ }
+}
+
+/*
+ * Early initialization of the MMU TLB code
+ */
+static void __early_init_mmu(int boot_cpu)
+{
+ extern unsigned int interrupt_base_book3e;
+ extern unsigned int exc_data_tlb_miss_htw_book3e;
+ extern unsigned int exc_instruction_tlb_miss_htw_book3e;
+
+ unsigned int *ibase = &interrupt_base_book3e;
+ unsigned int mas4;
+
+ /* XXX This will have to be decided at runtime, but right
+ * now our boot and TLB miss code hard wires it
+ */
+ mmu_linear_psize = MMU_PAGE_1G;
+
+
+ /* Check if HW tablewalk is present, and if yes, enable it by:
+ *
+ * - patching the TLB miss handlers to branch to the
+ * one dedicates to it
+ *
+ * - setting the global book3e_htw_enabled
+ *
+ * - Set MAS4:INDD and default page size
+ */
+
+ /* XXX This code only checks for TLB 0 capabilities and doesn't
+ * check what page size combos are supported by the HW. It
+ * also doesn't handle the case where a separate array holds
+ * the IND entries from the array loaded by the PT.
+ */
+ if (boot_cpu) {
+ unsigned int tlb0cfg = mfspr(SPRN_TLB0CFG);
+
+ /* Check if HW loader is supported */
+ if ((tlb0cfg & TLBnCFG_IND) &&
+ (tlb0cfg & TLBnCFG_PT)) {
+ patch_branch(ibase + (0x1c0 / 4),
+ (unsigned long)&exc_data_tlb_miss_htw_book3e, 0);
+ patch_branch(ibase + (0x1e0 / 4),
+ (unsigned long)&exc_instruction_tlb_miss_htw_book3e, 0);
+ book3e_htw_enabled = 1;
+ }
+ pr_info("MMU: Book3E Page Tables %s\n",
+ book3e_htw_enabled ? "Enabled" : "Disabled");
+ }
+
+ /* Set MAS4 based on page table setting */
+
+ mas4 = 0x4 << MAS4_WIMGED_SHIFT;
+ if (book3e_htw_enabled) {
+ mas4 |= mas4 | MAS4_INDD;
+#ifdef CONFIG_PPC_64K_PAGES
+ mas4 |= BOOK3E_PAGESZ_256M << MAS4_TSIZED_SHIFT;
+ mmu_pte_psize = MMU_PAGE_256M;
+#else
+ mas4 |= BOOK3E_PAGESZ_1M << MAS4_TSIZED_SHIFT;
+ mmu_pte_psize = MMU_PAGE_1M;
+#endif
+ } else {
+#ifdef CONFIG_PPC_64K_PAGES
+ mas4 |= BOOK3E_PAGESZ_64K << MAS4_TSIZED_SHIFT;
+#else
+ mas4 |= BOOK3E_PAGESZ_4K << MAS4_TSIZED_SHIFT;
+#endif
+ mmu_pte_psize = mmu_virtual_psize;
+ }
+ mtspr(SPRN_MAS4, mas4);
+
+ /* Set the global containing the top of the linear mapping
+ * for use by the TLB miss code
+ */
+ linear_map_top = lmb_end_of_DRAM();
+
+ /* A sync won't hurt us after mucking around with
+ * the MMU configuration
+ */
+ mb();
+}
+
+void __init early_init_mmu(void)
+{
+ __early_init_mmu(1);
+}
+
+void __cpuinit early_init_mmu_secondary(void)
+{
+ __early_init_mmu(0);
+}
+
+#endif /* CONFIG_PPC64 */
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