The patch titled
Subject: powerpc/64e: drop unused TLB miss handlers
has been added to the -mm mm-unstable branch. Its filename is
powerpc-64e-drop-unused-tlb-miss-handlers.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/powerpc-64e-drop-unused-tlb-miss-handlers.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Subject: powerpc/64e: drop unused TLB miss handlers
Date: Tue, 2 Jul 2024 15:51:18 +0200
There are two possibilities for book3e_htw_mode, PPC_HTW_E6500 or
PPC_HTW_NONE.
The TLB miss handlers are patched to use, respectively:
- exc_[data|indstruction]_tlb_miss_e6500_book3e
- exc_[data|indstruction]_tlb_miss_bolted_book3e
Which means the default handlers are never used. Remove those, and use
the bolted handlers (PPC_HTW_NONE) by default.
Link: https://lkml.kernel.org/r/9a670adc1771fb1871fba93ace5372f7eadc286f.1719928057.git.christophe.leroy@xxxxxxxxxx
Signed-off-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxxxxxx>
Cc: Jason Gunthorpe <jgg@xxxxxxxxxx>
Cc: Nicholas Piggin <npiggin@xxxxxxxxx>
Cc: Oscar Salvador <osalvador@xxxxxxx>
Cc: Peter Xu <peterx@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/powerpc/kernel/exceptions-64e.S | 4
arch/powerpc/mm/nohash/tlb_64e.c | 4
arch/powerpc/mm/nohash/tlb_low_64e.S | 226 -------------------------
3 files changed, 2 insertions(+), 232 deletions(-)
--- a/arch/powerpc/kernel/exceptions-64e.S~powerpc-64e-drop-unused-tlb-miss-handlers
+++ a/arch/powerpc/kernel/exceptions-64e.S
@@ -485,8 +485,8 @@ interrupt_base_book3e: /* fake trap
EXCEPTION_STUB(0x160, decrementer) /* 0x0900 */
EXCEPTION_STUB(0x180, fixed_interval) /* 0x0980 */
EXCEPTION_STUB(0x1a0, watchdog) /* 0x09f0 */
- EXCEPTION_STUB(0x1c0, data_tlb_miss)
- EXCEPTION_STUB(0x1e0, instruction_tlb_miss)
+ EXCEPTION_STUB(0x1c0, data_tlb_miss_bolted)
+ EXCEPTION_STUB(0x1e0, instruction_tlb_miss_bolted)
EXCEPTION_STUB(0x200, altivec_unavailable)
EXCEPTION_STUB(0x220, altivec_assist)
EXCEPTION_STUB(0x260, perfmon)
--- a/arch/powerpc/mm/nohash/tlb_64e.c~powerpc-64e-drop-unused-tlb-miss-handlers
+++ a/arch/powerpc/mm/nohash/tlb_64e.c
@@ -244,10 +244,6 @@ static void __init early_init_mmu_global
patch_exception(0x1c0, exc_data_tlb_miss_e6500_book3e);
patch_exception(0x1e0, exc_instruction_tlb_miss_e6500_book3e);
break;
- case PPC_HTW_NONE:
- patch_exception(0x1c0, exc_data_tlb_miss_bolted_book3e);
- patch_exception(0x1e0, exc_instruction_tlb_miss_bolted_book3e);
- break;
}
pr_info("MMU: Book3E HW tablewalk %s\n",
--- a/arch/powerpc/mm/nohash/tlb_low_64e.S~powerpc-64e-drop-unused-tlb-miss-handlers
+++ a/arch/powerpc/mm/nohash/tlb_low_64e.S
@@ -511,232 +511,6 @@ itlb_miss_fault_e6500:
tlb_epilog_bolted
b exc_instruction_storage_book3e
-/**********************************************************************
- * *
- * 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,r16,44 /* get region */
- xoris r15,r15,0xc
- cmpldi cr0,r15,0 /* linear mapping ? */
- beq tlb_load_linear /* yes -> go to linear map load */
- cmpldi cr1,r15,1 /* vmalloc mapping ? */
-
- /* 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
- */
- andis. 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
- */
- srdi. r15,r16,60 /* 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_user
- /* XXX replace the RMW cycles with immediate loads + writes */
-1: mfspr r10,SPRN_MAS1
- rlwinm r10,r10,0,16,1 /* Clear TID */
- mtspr SPRN_MAS1,r10
- beq+ cr1,normal_tlb_miss
-
- /* We got a crappy address, just fault with whatever DEAR and ESR
- * are here
- */
- 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,r16,44 /* get region */
- xoris r15,r15,0xc
- cmpldi cr0,r15,0 /* linear mapping ? */
- beq tlb_load_linear /* yes -> go to linear map load */
- cmpldi cr1,r15,1 /* vmalloc mapping ? */
-
- /* We do the user/kernel test for the PID here along with the RW test
- */
- li r11,_PAGE_PRESENT|_PAGE_BAP_UX /* Base perm */
- oris r11,r11,_PAGE_ACCESSED@h
-
- srdi. r15,r16,60 /* Check for user region */
- std r14,EX_TLB_ESR(r12) /* write crazy -1 to frame */
- beq normal_tlb_miss_user
-
- 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
- rlwinm r10,r10,0,16,1 /* Clear TID */
- mtspr SPRN_MAS1,r10
- beq+ cr1,normal_tlb_miss
-
- /* We got a crappy address, just 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_user:
-#ifdef CONFIG_PPC_KUAP
- mfspr r14,SPRN_MAS1
- rlwinm. r14,r14,0,0x3fff0000
- beq- normal_tlb_miss_access_fault /* KUAP fault */
-#endif
-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
- */
- srdi r15,r16,44
- oris r10,r15,0x1
- rldicl r14,r16,64-(PAGE_SHIFT-3),PAGE_SHIFT-3+4
- sldi r15,r10,44
- clrrdi r14,r14,19
- or r10,r15,r14
-
- ld r14,0(r10)
-
-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 r10,r16,12 /* Clear low crap in EA */
- rlwimi r10,r14,32-19,27,31 /* Insert WIMGE */
- mtspr SPRN_MAS2,r10
-
- /* Check page size, if not standard, update MAS1 */
- rldicl r10,r14,64-8,64-8
- cmpldi cr0,r10,BOOK3E_PAGESZ_4K
- 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:
- srdi r16,r15,32
- mtspr SPRN_MAS3,r15
- mtspr SPRN_MAS7,r16
-
- 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_EPILOG_SUCCESS
- rfi
-
-normal_tlb_miss_access_fault:
- /* We need to check if it was an instruction miss */
- andi. r10,r11,_PAGE_BAP_UX
- bne 1f
- ld r14,EX_TLB_DEAR(r12)
- ld r15,EX_TLB_ESR(r12)
- mtspr SPRN_DEAR,r14
- mtspr SPRN_ESR,r15
- TLB_MISS_EPILOG_ERROR
- b exc_data_storage_book3e
-1: 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:
_
Patches currently in -mm which might be from mpe@xxxxxxxxxxxxxx are
powerpc-64e-remove-unused-ibm-htw-code.patch
powerpc-64e-split-out-nohash-book3e-64-bit-code.patch
powerpc-64e-drop-e500-ifdefs-in-64-bit-code.patch
powerpc-64e-drop-mmu_ftr_type_fsl_e-checks-in-64-bit-code.patch
powerpc-64e-consolidate-tlb-miss-handler-patching.patch
powerpc-64e-drop-unused-tlb-miss-handlers.patch
