diff options
Diffstat (limited to 'arch/arc/mm/tlbex.S')
| -rw-r--r-- | arch/arc/mm/tlbex.S | 397 |
1 files changed, 189 insertions, 208 deletions
diff --git a/arch/arc/mm/tlbex.S b/arch/arc/mm/tlbex.S index 5c5bb23001b0..dc65e87a531f 100644 --- a/arch/arc/mm/tlbex.S +++ b/arch/arc/mm/tlbex.S @@ -1,26 +1,23 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ /* * TLB Exception Handling for ARC * * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com) * - * This program is free software; you can redistribute it and/or modify - * it under the terms of the GNU General Public License version 2 as - * published by the Free Software Foundation. - * * Vineetg: April 2011 : - * -MMU v1: moved out legacy code into a seperate file + * -MMU v1: moved out legacy code into a separate file * -MMU v3: PD{0,1} bits layout changed: They don't overlap anymore, * helps avoid a shift when preparing PD0 from PTE * * Vineetg: July 2009 - * -For MMU V2, we need not do heuristics at the time of commiting a D-TLB - * entry, so that it doesn't knock out it's I-TLB entry + * -For MMU V2, we need not do heuristics at the time of committing a D-TLB + * entry, so that it doesn't knock out its I-TLB entry * -Some more fine tuning: * bmsk instead of add, asl.cc instead of branch, delay slot utilise etc * * Vineetg: July 2009 * -Practically rewrote the I/D TLB Miss handlers - * Now 40 and 135 instructions a peice as compared to 131 and 449 resp. + * Now 40 and 135 instructions apiece as compared to 131 and 449 resp. * Hence Leaner by 1.5 K * Used Conditional arithmetic to replace excessive branching * Also used short instructions wherever possible @@ -35,26 +32,43 @@ * Rahul Trivedi, Amit Bhor: Codito Technologies 2004 */ - .cpu A7 - #include <linux/linkage.h> +#include <linux/pgtable.h> #include <asm/entry.h> #include <asm/mmu.h> -#include <asm/pgtable.h> #include <asm/arcregs.h> #include <asm/cache.h> #include <asm/processor.h> -#if (CONFIG_ARC_MMU_VER == 1) -#include <asm/tlb-mmu1.h> -#endif -;-------------------------------------------------------------------------- -; scratch memory to save the registers (r0-r3) used to code TLB refill Handler -; For details refer to comments before TLBMISS_FREEUP_REGS below +#ifdef CONFIG_ISA_ARCOMPACT +;----------------------------------------------------------------- +; ARC700 Exception Handling doesn't auto-switch stack and it only provides +; ONE scratch AUX reg "ARC_REG_SCRATCH_DATA0" +; +; For Non-SMP, the scratch AUX reg is repurposed to cache task PGD, so a +; "global" is used to free-up FIRST core reg to be able to code the rest of +; exception prologue (IRQ auto-disabled on Exceptions, so it's IRQ-safe). +; Since the Fast Path TLB Miss handler is coded with 4 regs, the remaining 3 +; need to be saved as well by extending the "global" to be 4 words. Hence +; ".size ex_saved_reg1, 16" +; [All of this dance is to avoid stack switching for each TLB Miss, since we +; only need to save only a handful of regs, as opposed to complete reg file] +; +; For ARC700 SMP, the "global" obviously can't be used for free up the FIRST +; core reg as it will not be SMP safe. +; Thus scratch AUX reg is used (and no longer used to cache task PGD). +; To save the rest of 3 regs - per cpu, the global is made "per-cpu". +; Epilogue thus has to locate the "per-cpu" storage for regs. +; To avoid cache line bouncing the per-cpu global is aligned/sized per +; L1_CACHE_SHIFT, despite fundamentally needing to be 12 bytes only. Hence +; ".size ex_saved_reg1, (CONFIG_NR_CPUS << L1_CACHE_SHIFT)" + +; As simple as that.... ;-------------------------------------------------------------------------- +; scratch memory to save [r0-r3] used to code TLB refill Handler ARCFP_DATA ex_saved_reg1 - .align 1 << L1_CACHE_SHIFT ; IMP: Must be Cache Line aligned + .align 1 << L1_CACHE_SHIFT .type ex_saved_reg1, @object #ifdef CONFIG_SMP .size ex_saved_reg1, (CONFIG_NR_CPUS << L1_CACHE_SHIFT) @@ -66,54 +80,79 @@ ex_saved_reg1: .zero 16 #endif -;============================================================================ -; Troubleshooting Stuff -;============================================================================ - -; Linux keeps ASID (Address Space ID) in task->active_mm->context.asid -; When Creating TLB Entries, instead of doing 3 dependent loads from memory, -; we use the MMU PID Reg to get current ASID. -; In bizzare scenrios SW and HW ASID can get out-of-sync which is trouble. -; So we try to detect this in TLB Mis shandler - - -.macro DBG_ASID_MISMATCH - -#ifdef CONFIG_ARC_DBG_TLB_PARANOIA - - ; make sure h/w ASID is same as s/w ASID - - GET_CURR_TASK_ON_CPU r3 - ld r0, [r3, TASK_ACT_MM] - ld r0, [r0, MM_CTXT+MM_CTXT_ASID] - - lr r1, [ARC_REG_PID] - and r1, r1, 0xFF - breq r1, r0, 5f - - ; Error if H/w and S/w ASID don't match, but NOT if in kernel mode - lr r0, [erstatus] - bbit0 r0, STATUS_U_BIT, 5f - - ; We sure are in troubled waters, Flag the error, but to do so - ; need to switch to kernel mode stack to call error routine - GET_TSK_STACK_BASE r3, sp +.macro TLBMISS_FREEUP_REGS +#ifdef CONFIG_SMP + sr r0, [ARC_REG_SCRATCH_DATA0] ; freeup r0 to code with + GET_CPU_ID r0 ; get to per cpu scratch mem, + asl r0, r0, L1_CACHE_SHIFT ; cache line wide per cpu + add r0, @ex_saved_reg1, r0 +#else + st r0, [@ex_saved_reg1] + mov_s r0, @ex_saved_reg1 +#endif + st_s r1, [r0, 4] + st_s r2, [r0, 8] + st_s r3, [r0, 12] +.endm - ; Call printk to shoutout aloud - mov r0, 1 - j print_asid_mismatch +.macro TLBMISS_RESTORE_REGS +#ifdef CONFIG_SMP + GET_CPU_ID r0 ; get to per cpu scratch mem + asl r0, r0, L1_CACHE_SHIFT ; each is cache line wide + add r0, @ex_saved_reg1, r0 + ld_s r3, [r0,12] + ld_s r2, [r0, 8] + ld_s r1, [r0, 4] + lr r0, [ARC_REG_SCRATCH_DATA0] +#else + mov_s r0, @ex_saved_reg1 + ld_s r3, [r0,12] + ld_s r2, [r0, 8] + ld_s r1, [r0, 4] + ld_s r0, [r0] +#endif +.endm -5: ; ASIDs match so proceed normally - nop +#else /* ARCv2 */ +.macro TLBMISS_FREEUP_REGS +#ifdef CONFIG_ARC_HAS_LL64 + std r0, [sp, -16] + std r2, [sp, -8] +#else + PUSH r0 + PUSH r1 + PUSH r2 + PUSH r3 #endif +.endm +.macro TLBMISS_RESTORE_REGS +#ifdef CONFIG_ARC_HAS_LL64 + ldd r0, [sp, -16] + ldd r2, [sp, -8] +#else + POP r3 + POP r2 + POP r1 + POP r0 +#endif .endm +#endif + ;============================================================================ ;TLB Miss handling Code ;============================================================================ +#ifndef PMD_SHIFT +#define PMD_SHIFT PUD_SHIFT +#endif + +#ifndef PUD_SHIFT +#define PUD_SHIFT PGDIR_SHIFT +#endif + ;----------------------------------------------------------------------------- ; This macro does the page-table lookup for the faulting address. ; OUT: r0 = PTE faulted on, r1 = ptr to PTE, r2 = Faulting V-address @@ -121,7 +160,7 @@ ex_saved_reg1: lr r2, [efa] -#ifndef CONFIG_SMP +#ifdef CONFIG_ISA_ARCV2 lr r1, [ARC_REG_SCRATCH_DATA0] ; current pgd #else GET_CURR_TASK_ON_CPU r1 @@ -130,44 +169,80 @@ ex_saved_reg1: #endif lsr r0, r2, PGDIR_SHIFT ; Bits for indexing into PGD - ld.as r1, [r1, r0] ; PGD entry corresp to faulting addr - and.f r1, r1, PAGE_MASK ; Ignoring protection and other flags - ; contains Ptr to Page Table - bz.d do_slow_path_pf ; if no Page Table, do page fault + ld.as r3, [r1, r0] ; PGD entry corresp to faulting addr + tst r3, r3 + bz do_slow_path_pf ; if no Page Table, do page fault + +#if CONFIG_PGTABLE_LEVELS > 3 + lsr r0, r2, PUD_SHIFT ; Bits for indexing into PUD + and r0, r0, (PTRS_PER_PUD - 1) + ld.as r1, [r3, r0] ; PMD entry + tst r1, r1 + bz do_slow_path_pf + mov r3, r1 +#endif + +#if CONFIG_PGTABLE_LEVELS > 2 + lsr r0, r2, PMD_SHIFT ; Bits for indexing into PMD + and r0, r0, (PTRS_PER_PMD - 1) + ld.as r1, [r3, r0] ; PMD entry + tst r1, r1 + bz do_slow_path_pf + mov r3, r1 +#endif + +#ifdef CONFIG_TRANSPARENT_HUGEPAGE + and.f 0, r3, _PAGE_HW_SZ ; Is this Huge PMD (thp) + add2.nz r1, r1, r0 + bnz.d 2f ; YES: PGD == PMD has THP PTE: stop pgd walk + mov.nz r0, r3 + +#endif + and r1, r3, PAGE_MASK ; Get the PTE entry: The idea is ; (1) x = addr >> PAGE_SHIFT -> masks page-off bits from @fault-addr ; (2) y = x & (PTRS_PER_PTE - 1) -> to get index - ; (3) z = pgtbl[y] - ; To avoid the multiply by in end, we do the -2, <<2 below - - lsr r0, r2, (PAGE_SHIFT - 2) - and r0, r0, ( (PTRS_PER_PTE - 1) << 2) - ld.aw r0, [r1, r0] ; get PTE and PTE ptr for fault addr -#ifdef CONFIG_ARC_DBG_TLB_MISS_COUNT - and.f 0, r0, _PAGE_PRESENT - bz 1f - ld r3, [num_pte_not_present] - add r3, r3, 1 - st r3, [num_pte_not_present] -1: + ; (3) z = (pgtbl + y * 4) + +#ifdef CONFIG_ARC_HAS_PAE40 +#define PTE_SIZE_LOG 3 /* 8 == 2 ^ 3 */ +#else +#define PTE_SIZE_LOG 2 /* 4 == 2 ^ 2 */ #endif + ; multiply in step (3) above avoided by shifting lesser in step (1) + lsr r0, r2, ( PAGE_SHIFT - PTE_SIZE_LOG ) + and r0, r0, ( (PTRS_PER_PTE - 1) << PTE_SIZE_LOG ) + ld.aw r0, [r1, r0] ; r0: PTE (lower word only for PAE40) + ; r1: PTE ptr + +2: + .endm ;----------------------------------------------------------------- ; Convert Linux PTE entry into TLB entry ; A one-word PTE entry is programmed as two-word TLB Entry [PD0:PD1] in mmu +; (for PAE40, two-words PTE, while three-word TLB Entry [PD0:PD1:PD1HI]) ; IN: r0 = PTE, r1 = ptr to PTE .macro CONV_PTE_TO_TLB - and r3, r0, PTE_BITS_IN_PD1 ; Extract permission flags+PFN from PTE - sr r3, [ARC_REG_TLBPD1] ; these go in PD1 + and r3, r0, PTE_BITS_RWX ; r w x + asl r2, r3, 3 ; Kr Kw Kx 0 0 0 (GLOBAL, kernel only) + and.f 0, r0, _PAGE_GLOBAL + or.z r2, r2, r3 ; Kr Kw Kx Ur Uw Ux (!GLOBAL, user page) + + and r3, r0, PTE_BITS_NON_RWX_IN_PD1 ; Extract PFN+cache bits from PTE + or r3, r3, r2 + + sr r3, [ARC_REG_TLBPD1] ; paddr[31..13] | Kr Kw Kx Ur Uw Ux | C +#ifdef CONFIG_ARC_HAS_PAE40 + ld r3, [r1, 4] ; paddr[39..32] + sr r3, [ARC_REG_TLBPD1HI] +#endif and r2, r0, PTE_BITS_IN_PD0 ; Extract other PTE flags: (V)alid, (G)lb -#if (CONFIG_ARC_MMU_VER <= 2) /* Neednot be done with v3 onwards */ - lsr r2, r2 ; shift PTE flags to match layout in PD0 -#endif lr r3,[ARC_REG_TLBPD0] ; MMU prepares PD0 with vaddr and asid @@ -179,80 +254,21 @@ ex_saved_reg1: ; Commit the TLB entry into MMU .macro COMMIT_ENTRY_TO_MMU +#ifdef CONFIG_ARC_MMU_V3 /* Get free TLB slot: Set = computed from vaddr, way = random */ sr TLBGetIndex, [ARC_REG_TLBCOMMAND] /* Commit the Write */ -#if (CONFIG_ARC_MMU_VER >= 2) /* introduced in v2 */ sr TLBWriteNI, [ARC_REG_TLBCOMMAND] -#else - sr TLBWrite, [ARC_REG_TLBCOMMAND] -#endif -.endm - -;----------------------------------------------------------------- -; ARC700 Exception Handling doesn't auto-switch stack and it only provides -; ONE scratch AUX reg "ARC_REG_SCRATCH_DATA0" -; -; For Non-SMP, the scratch AUX reg is repurposed to cache task PGD, so a -; "global" is used to free-up FIRST core reg to be able to code the rest of -; exception prologue (IRQ auto-disabled on Exceptions, so it's IRQ-safe). -; Since the Fast Path TLB Miss handler is coded with 4 regs, the remaining 3 -; need to be saved as well by extending the "global" to be 4 words. Hence -; ".size ex_saved_reg1, 16" -; [All of this dance is to avoid stack switching for each TLB Miss, since we -; only need to save only a handful of regs, as opposed to complete reg file] -; -; For ARC700 SMP, the "global" obviously can't be used for free up the FIRST -; core reg as it will not be SMP safe. -; Thus scratch AUX reg is used (and no longer used to cache task PGD). -; To save the rest of 3 regs - per cpu, the global is made "per-cpu". -; Epilogue thus has to locate the "per-cpu" storage for regs. -; To avoid cache line bouncing the per-cpu global is aligned/sized per -; L1_CACHE_SHIFT, despite fundamentally needing to be 12 bytes only. Hence -; ".size ex_saved_reg1, (CONFIG_NR_CPUS << L1_CACHE_SHIFT)" - -; As simple as that.... -.macro TLBMISS_FREEUP_REGS -#ifdef CONFIG_SMP - sr r0, [ARC_REG_SCRATCH_DATA0] ; freeup r0 to code with - GET_CPU_ID r0 ; get to per cpu scratch mem, - lsl r0, r0, L1_CACHE_SHIFT ; cache line wide per cpu - add r0, @ex_saved_reg1, r0 #else - st r0, [@ex_saved_reg1] - mov_s r0, @ex_saved_reg1 + sr TLBInsertEntry, [ARC_REG_TLBCOMMAND] #endif - st_s r1, [r0, 4] - st_s r2, [r0, 8] - st_s r3, [r0, 12] - ; VERIFY if the ASID in MMU-PID Reg is same as - ; one in Linux data structures - - DBG_ASID_MISMATCH +88: .endm -;----------------------------------------------------------------- -.macro TLBMISS_RESTORE_REGS -#ifdef CONFIG_SMP - GET_CPU_ID r0 ; get to per cpu scratch mem - lsl r0, r0, L1_CACHE_SHIFT ; each is cache line wide - add r0, @ex_saved_reg1, r0 - ld_s r3, [r0,12] - ld_s r2, [r0, 8] - ld_s r1, [r0, 4] - lr r0, [ARC_REG_SCRATCH_DATA0] -#else - mov_s r0, @ex_saved_reg1 - ld_s r3, [r0,12] - ld_s r2, [r0, 8] - ld_s r1, [r0, 4] - ld_s r0, [r0] -#endif -.endm ARCFP_CODE ;Fast Path Code, candidate for ICCM @@ -260,16 +276,10 @@ ARCFP_CODE ;Fast Path Code, candidate for ICCM ; I-TLB Miss Exception Handler ;----------------------------------------------------------------------------- -ARC_ENTRY EV_TLBMissI +ENTRY(EV_TLBMissI) TLBMISS_FREEUP_REGS -#ifdef CONFIG_ARC_DBG_TLB_MISS_COUNT - ld r0, [@numitlb] - add r0, r0, 1 - st r0, [@numitlb] -#endif - ;---------------------------------------------------------------- ; Get the PTE corresponding to V-addr accessed, r2 is setup with EFA LOAD_FAULT_PTE @@ -277,8 +287,8 @@ ARC_ENTRY EV_TLBMissI ;---------------------------------------------------------------- ; VERIFY_PTE: Check if PTE permissions approp for executing code cmp_s r2, VMALLOC_START - mov.lo r2, (_PAGE_PRESENT | _PAGE_U_EXECUTE) - mov.hs r2, (_PAGE_PRESENT | _PAGE_K_EXECUTE) + mov_s r2, (_PAGE_PRESENT | _PAGE_EXECUTE) + or.hs r2, r2, _PAGE_GLOBAL and r3, r0, r2 ; Mask out NON Flag bits from PTE xor.f r3, r3, r2 ; check ( ( pte & flags_test ) == flags_test ) @@ -291,24 +301,19 @@ ARC_ENTRY EV_TLBMissI CONV_PTE_TO_TLB COMMIT_ENTRY_TO_MMU TLBMISS_RESTORE_REGS +EV_TLBMissI_fast_ret: ; additional label for VDK OS-kit instrumentation rtie -ARC_EXIT EV_TLBMissI +END(EV_TLBMissI) ;----------------------------------------------------------------------------- ; D-TLB Miss Exception Handler ;----------------------------------------------------------------------------- -ARC_ENTRY EV_TLBMissD +ENTRY(EV_TLBMissD) TLBMISS_FREEUP_REGS -#ifdef CONFIG_ARC_DBG_TLB_MISS_COUNT - ld r0, [@numdtlb] - add r0, r0, 1 - st r0, [@numdtlb] -#endif - ;---------------------------------------------------------------- ; Get the PTE corresponding to V-addr accessed ; If PTE exists, it will setup, r0 = PTE, r1 = Ptr to PTE, r2 = EFA @@ -317,26 +322,21 @@ ARC_ENTRY EV_TLBMissD ;---------------------------------------------------------------- ; VERIFY_PTE: Chk if PTE permissions approp for data access (R/W/R+W) - mov_s r2, 0 + cmp_s r2, VMALLOC_START + mov_s r2, _PAGE_PRESENT ; common bit for K/U PTE + or.hs r2, r2, _PAGE_GLOBAL ; kernel PTE only + + ; Linux PTE [RWX] bits are semantically overloaded: + ; -If PAGE_GLOBAL set, they refer to kernel-only flags (vmalloc) + ; -Otherwise they are user-mode permissions, and those are exactly + ; same for kernel mode as well (e.g. copy_(to|from)_user) + lr r3, [ecr] btst_s r3, ECR_C_BIT_DTLB_LD_MISS ; Read Access - or.nz r2, r2, _PAGE_U_READ ; chk for Read flag in PTE + or.nz r2, r2, _PAGE_READ ; chk for Read flag in PTE btst_s r3, ECR_C_BIT_DTLB_ST_MISS ; Write Access - or.nz r2, r2, _PAGE_U_WRITE ; chk for Write flag in PTE - ; Above laddering takes care of XCHG access - ; which is both Read and Write - - ; If kernel mode access, ; make _PAGE_xx flags as _PAGE_K_xx - ; For copy_(to|from)_user, despite exception taken in kernel mode, - ; this code is not hit, because EFA would still be the user mode - ; address (EFA < 0x6000_0000). - ; This code is for legit kernel mode faults, vmalloc specifically - ; (EFA: 0x7000_0000 to 0x7FFF_FFFF) - - lr r3, [efa] - cmp r3, VMALLOC_START - 1 ; If kernel mode access - asl.hi r2, r2, 3 ; make _PAGE_xx flags as _PAGE_K_xx - or r2, r2, _PAGE_PRESENT ; Common flag for K/U mode + or.nz r2, r2, _PAGE_WRITE ; chk for Write flag in PTE + ; Above laddering takes care of XCHG access (both R and W) ; By now, r2 setup with all the Flags we need to check in PTE and r3, r0, r2 ; Mask out NON Flag bits from PTE @@ -344,54 +344,35 @@ ARC_ENTRY EV_TLBMissD ;---------------------------------------------------------------- ; UPDATE_PTE: Let Linux VM know that page was accessed/dirty - lr r3, [ecr] or r0, r0, _PAGE_ACCESSED ; Accessed bit always - btst_s r3, ECR_C_BIT_DTLB_ST_MISS ; See if it was a Write Access ? - or.nz r0, r0, _PAGE_MODIFIED ; if Write, set Dirty bit as well + or.nz r0, r0, _PAGE_DIRTY ; if Write, set Dirty bit as well st_s r0, [r1] ; Write back PTE CONV_PTE_TO_TLB -#if (CONFIG_ARC_MMU_VER == 1) - ; MMU with 2 way set assoc J-TLB, needs some help in pathetic case of - ; memcpy where 3 parties contend for 2 ways, ensuing a livelock. - ; But only for old MMU or one with Metal Fix - TLB_WRITE_HEURISTICS -#endif - COMMIT_ENTRY_TO_MMU TLBMISS_RESTORE_REGS +EV_TLBMissD_fast_ret: ; additional label for VDK OS-kit instrumentation rtie ;-------- Common routine to call Linux Page Fault Handler ----------- do_slow_path_pf: +#ifdef CONFIG_ISA_ARCV2 + ; Set Z flag if exception in U mode. Hardware micro-ops do this on any + ; taken interrupt/exception, and thus is already the case at the entry + ; above, but ensuing code would have already clobbered. + ; EXCEPTION_PROLOGUE called in slow path, relies on correct Z flag set + + lr r2, [erstatus] + and r2, r2, STATUS_U_MASK + bxor.f 0, r2, STATUS_U_BIT +#endif + ; Restore the 4-scratch regs saved by fast path miss handler TLBMISS_RESTORE_REGS ; Slow path TLB Miss handled as a regular ARC Exception ; (stack switching / save the complete reg-file). - ; That requires freeing up r9 - EXCPN_PROLOG_FREEUP_REG r9 - - lr r9, [erstatus] - - SWITCH_TO_KERNEL_STK - SAVE_ALL_SYS - - ; ------- setup args for Linux Page fault Hanlder --------- - mov_s r0, sp - lr r1, [efa] - - ; We don't want exceptions to be disabled while the fault is handled. - ; Now that we have saved the context we return from exception hence - ; exceptions get re-enable - - FAKE_RET_FROM_EXCPN r9 - - bl do_page_fault - b ret_from_exception - -ARC_EXIT EV_TLBMissD - -ARC_ENTRY EV_TLBMissB ; Bogus entry to measure sz of DTLBMiss hdlr + b call_do_page_fault +END(EV_TLBMissD) |