kevin/linux
1
Fork 0
Code

powerpc/64e: drop unused TLB miss handlers

Browse Source 
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@csgroup.eu
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Peter Xu <peterx@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Michael Ellerman 2024-07-02 15:51:18 +02:00 committed by Andrew Morton
parent 264488bf59
commit 0db46aaabe
3 changed files with 2 additions and 232 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
arch/powerpc/kernel/exceptions-64e.S
View File

@ -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)

4
arch/powerpc/mm/nohash/tlb_64e.c
View File

@ -244,10 +244,6 @@ static void __init early_init_mmu_global(void)
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",

226
arch/powerpc/mm/nohash/tlb_low_64e.S
View File

@ -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: