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Diffstat (limited to 'arch/arc/mm/tlb.c')
| -rw-r--r-- | arch/arc/mm/tlb.c | 984 |
1 files changed, 984 insertions, 0 deletions
diff --git a/arch/arc/mm/tlb.c b/arch/arc/mm/tlb.c new file mode 100644 index 000000000..9c7c68247 --- /dev/null +++ b/arch/arc/mm/tlb.c @@ -0,0 +1,984 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * TLB Management (flush/create/diagnostics) for ARC700 + * + * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com) + * + * vineetg: Aug 2011 + * -Reintroduce duplicate PD fixup - some customer chips still have the issue + * + * vineetg: May 2011 + * -No need to flush_cache_page( ) for each call to update_mmu_cache() + * some of the LMBench tests improved amazingly + * = page-fault thrice as fast (75 usec to 28 usec) + * = mmap twice as fast (9.6 msec to 4.6 msec), + * = fork (5.3 msec to 3.7 msec) + * + * vineetg: April 2011 : + * -MMU v3: PD{0,1} bits layout changed: They don't overlap anymore, + * helps avoid a shift when preparing PD0 from PTE + * + * vineetg: April 2011 : Preparing for MMU V3 + * -MMU v2/v3 BCRs decoded differently + * -Remove TLB_SIZE hardcoding as it's variable now: 256 or 512 + * -tlb_entry_erase( ) can be void + * -local_flush_tlb_range( ): + * = need not "ceil" @end + * = walks MMU only if range spans < 32 entries, as opposed to 256 + * + * Vineetg: Sept 10th 2008 + * -Changes related to MMU v2 (Rel 4.8) + * + * Vineetg: Aug 29th 2008 + * -In TLB Flush operations (Metal Fix MMU) there is a explicit command to + * flush Micro-TLBS. If TLB Index Reg is invalid prior to TLBIVUTLB cmd, + * it fails. Thus need to load it with ANY valid value before invoking + * TLBIVUTLB cmd + * + * Vineetg: Aug 21th 2008: + * -Reduced the duration of IRQ lockouts in TLB Flush routines + * -Multiple copies of TLB erase code separated into a "single" function + * -In TLB Flush routines, interrupt disabling moved UP to retrieve ASID + * in interrupt-safe region. + * + * Vineetg: April 23rd Bug #93131 + * Problem: tlb_flush_kernel_range() doesn't do anything if the range to + * flush is more than the size of TLB itself. + * + * Rahul Trivedi : Codito Technologies 2004 + */ + +#include <linux/module.h> +#include <linux/bug.h> +#include <linux/mm_types.h> + +#include <asm/arcregs.h> +#include <asm/setup.h> +#include <asm/mmu_context.h> +#include <asm/mmu.h> + +/* Need for ARC MMU v2 + * + * ARC700 MMU-v1 had a Joint-TLB for Code and Data and is 2 way set-assoc. + * For a memcpy operation with 3 players (src/dst/code) such that all 3 pages + * map into same set, there would be contention for the 2 ways causing severe + * Thrashing. + * + * Although J-TLB is 2 way set assoc, ARC700 caches J-TLB into uTLBS which has + * much higher associativity. u-D-TLB is 8 ways, u-I-TLB is 4 ways. + * Given this, the thrashing problem should never happen because once the 3 + * J-TLB entries are created (even though 3rd will knock out one of the prev + * two), the u-D-TLB and u-I-TLB will have what is required to accomplish memcpy + * + * Yet we still see the Thrashing because a J-TLB Write cause flush of u-TLBs. + * This is a simple design for keeping them in sync. So what do we do? + * The solution which James came up was pretty neat. It utilised the assoc + * of uTLBs by not invalidating always but only when absolutely necessary. + * + * - Existing TLB commands work as before + * - New command (TLBWriteNI) for TLB write without clearing uTLBs + * - New command (TLBIVUTLB) to invalidate uTLBs. + * + * The uTLBs need only be invalidated when pages are being removed from the + * OS page table. If a 'victim' TLB entry is being overwritten in the main TLB + * as a result of a miss, the removed entry is still allowed to exist in the + * uTLBs as it is still valid and present in the OS page table. This allows the + * full associativity of the uTLBs to hide the limited associativity of the main + * TLB. + * + * During a miss handler, the new "TLBWriteNI" command is used to load + * entries without clearing the uTLBs. + * + * When the OS page table is updated, TLB entries that may be associated with a + * removed page are removed (flushed) from the TLB using TLBWrite. In this + * circumstance, the uTLBs must also be cleared. This is done by using the + * existing TLBWrite command. An explicit IVUTLB is also required for those + * corner cases when TLBWrite was not executed at all because the corresp + * J-TLB entry got evicted/replaced. + */ + + +/* A copy of the ASID from the PID reg is kept in asid_cache */ +DEFINE_PER_CPU(unsigned int, asid_cache) = MM_CTXT_FIRST_CYCLE; + +static int __read_mostly pae_exists; + +/* + * Utility Routine to erase a J-TLB entry + * Caller needs to setup Index Reg (manually or via getIndex) + */ +static inline void __tlb_entry_erase(void) +{ + write_aux_reg(ARC_REG_TLBPD1, 0); + + if (is_pae40_enabled()) + write_aux_reg(ARC_REG_TLBPD1HI, 0); + + write_aux_reg(ARC_REG_TLBPD0, 0); + write_aux_reg(ARC_REG_TLBCOMMAND, TLBWrite); +} + +static void utlb_invalidate(void) +{ +#if (CONFIG_ARC_MMU_VER >= 2) + +#if (CONFIG_ARC_MMU_VER == 2) + /* MMU v2 introduced the uTLB Flush command. + * There was however an obscure hardware bug, where uTLB flush would + * fail when a prior probe for J-TLB (both totally unrelated) would + * return lkup err - because the entry didn't exist in MMU. + * The Workaround was to set Index reg with some valid value, prior to + * flush. This was fixed in MMU v3 + */ + unsigned int idx; + + /* make sure INDEX Reg is valid */ + idx = read_aux_reg(ARC_REG_TLBINDEX); + + /* If not write some dummy val */ + if (unlikely(idx & TLB_LKUP_ERR)) + write_aux_reg(ARC_REG_TLBINDEX, 0xa); +#endif + + write_aux_reg(ARC_REG_TLBCOMMAND, TLBIVUTLB); +#endif + +} + +#if (CONFIG_ARC_MMU_VER < 4) + +static inline unsigned int tlb_entry_lkup(unsigned long vaddr_n_asid) +{ + unsigned int idx; + + write_aux_reg(ARC_REG_TLBPD0, vaddr_n_asid); + + write_aux_reg(ARC_REG_TLBCOMMAND, TLBProbe); + idx = read_aux_reg(ARC_REG_TLBINDEX); + + return idx; +} + +static void tlb_entry_erase(unsigned int vaddr_n_asid) +{ + unsigned int idx; + + /* Locate the TLB entry for this vaddr + ASID */ + idx = tlb_entry_lkup(vaddr_n_asid); + + /* No error means entry found, zero it out */ + if (likely(!(idx & TLB_LKUP_ERR))) { + __tlb_entry_erase(); + } else { + /* Duplicate entry error */ + WARN(idx == TLB_DUP_ERR, "Probe returned Dup PD for %x\n", + vaddr_n_asid); + } +} + +static void tlb_entry_insert(unsigned int pd0, pte_t pd1) +{ + unsigned int idx; + + /* + * First verify if entry for this vaddr+ASID already exists + * This also sets up PD0 (vaddr, ASID..) for final commit + */ + idx = tlb_entry_lkup(pd0); + + /* + * If Not already present get a free slot from MMU. + * Otherwise, Probe would have located the entry and set INDEX Reg + * with existing location. This will cause Write CMD to over-write + * existing entry with new PD0 and PD1 + */ + if (likely(idx & TLB_LKUP_ERR)) + write_aux_reg(ARC_REG_TLBCOMMAND, TLBGetIndex); + + /* setup the other half of TLB entry (pfn, rwx..) */ + write_aux_reg(ARC_REG_TLBPD1, pd1); + + /* + * Commit the Entry to MMU + * It doesn't sound safe to use the TLBWriteNI cmd here + * which doesn't flush uTLBs. I'd rather be safe than sorry. + */ + write_aux_reg(ARC_REG_TLBCOMMAND, TLBWrite); +} + +#else /* CONFIG_ARC_MMU_VER >= 4) */ + +static void tlb_entry_erase(unsigned int vaddr_n_asid) +{ + write_aux_reg(ARC_REG_TLBPD0, vaddr_n_asid | _PAGE_PRESENT); + write_aux_reg(ARC_REG_TLBCOMMAND, TLBDeleteEntry); +} + +static void tlb_entry_insert(unsigned int pd0, pte_t pd1) +{ + write_aux_reg(ARC_REG_TLBPD0, pd0); + write_aux_reg(ARC_REG_TLBPD1, pd1); + + if (is_pae40_enabled()) + write_aux_reg(ARC_REG_TLBPD1HI, (u64)pd1 >> 32); + + write_aux_reg(ARC_REG_TLBCOMMAND, TLBInsertEntry); +} + +#endif + +/* + * Un-conditionally (without lookup) erase the entire MMU contents + */ + +noinline void local_flush_tlb_all(void) +{ + struct cpuinfo_arc_mmu *mmu = &cpuinfo_arc700[smp_processor_id()].mmu; + unsigned long flags; + unsigned int entry; + int num_tlb = mmu->sets * mmu->ways; + + local_irq_save(flags); + + /* Load PD0 and PD1 with template for a Blank Entry */ + write_aux_reg(ARC_REG_TLBPD1, 0); + + if (is_pae40_enabled()) + write_aux_reg(ARC_REG_TLBPD1HI, 0); + + write_aux_reg(ARC_REG_TLBPD0, 0); + + for (entry = 0; entry < num_tlb; entry++) { + /* write this entry to the TLB */ + write_aux_reg(ARC_REG_TLBINDEX, entry); + write_aux_reg(ARC_REG_TLBCOMMAND, TLBWriteNI); + } + + if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE)) { + const int stlb_idx = 0x800; + + /* Blank sTLB entry */ + write_aux_reg(ARC_REG_TLBPD0, _PAGE_HW_SZ); + + for (entry = stlb_idx; entry < stlb_idx + 16; entry++) { + write_aux_reg(ARC_REG_TLBINDEX, entry); + write_aux_reg(ARC_REG_TLBCOMMAND, TLBWriteNI); + } + } + + utlb_invalidate(); + + local_irq_restore(flags); +} + +/* + * Flush the entire MM for userland. The fastest way is to move to Next ASID + */ +noinline void local_flush_tlb_mm(struct mm_struct *mm) +{ + /* + * Small optimisation courtesy IA64 + * flush_mm called during fork,exit,munmap etc, multiple times as well. + * Only for fork( ) do we need to move parent to a new MMU ctxt, + * all other cases are NOPs, hence this check. + */ + if (atomic_read(&mm->mm_users) == 0) + return; + + /* + * - Move to a new ASID, but only if the mm is still wired in + * (Android Binder ended up calling this for vma->mm != tsk->mm, + * causing h/w - s/w ASID to get out of sync) + * - Also get_new_mmu_context() new implementation allocates a new + * ASID only if it is not allocated already - so unallocate first + */ + destroy_context(mm); + if (current->mm == mm) + get_new_mmu_context(mm); +} + +/* + * Flush a Range of TLB entries for userland. + * @start is inclusive, while @end is exclusive + * Difference between this and Kernel Range Flush is + * -Here the fastest way (if range is too large) is to move to next ASID + * without doing any explicit Shootdown + * -In case of kernel Flush, entry has to be shot down explicitly + */ +void local_flush_tlb_range(struct vm_area_struct *vma, unsigned long start, + unsigned long end) +{ + const unsigned int cpu = smp_processor_id(); + unsigned long flags; + + /* If range @start to @end is more than 32 TLB entries deep, + * its better to move to a new ASID rather than searching for + * individual entries and then shooting them down + * + * The calc above is rough, doesn't account for unaligned parts, + * since this is heuristics based anyways + */ + if (unlikely((end - start) >= PAGE_SIZE * 32)) { + local_flush_tlb_mm(vma->vm_mm); + return; + } + + /* + * @start moved to page start: this alone suffices for checking + * loop end condition below, w/o need for aligning @end to end + * e.g. 2000 to 4001 will anyhow loop twice + */ + start &= PAGE_MASK; + + local_irq_save(flags); + + if (asid_mm(vma->vm_mm, cpu) != MM_CTXT_NO_ASID) { + while (start < end) { + tlb_entry_erase(start | hw_pid(vma->vm_mm, cpu)); + start += PAGE_SIZE; + } + } + + local_irq_restore(flags); +} + +/* Flush the kernel TLB entries - vmalloc/modules (Global from MMU perspective) + * @start, @end interpreted as kvaddr + * Interestingly, shared TLB entries can also be flushed using just + * @start,@end alone (interpreted as user vaddr), although technically SASID + * is also needed. However our smart TLbProbe lookup takes care of that. + */ +void local_flush_tlb_kernel_range(unsigned long start, unsigned long end) +{ + unsigned long flags; + + /* exactly same as above, except for TLB entry not taking ASID */ + + if (unlikely((end - start) >= PAGE_SIZE * 32)) { + local_flush_tlb_all(); + return; + } + + start &= PAGE_MASK; + + local_irq_save(flags); + while (start < end) { + tlb_entry_erase(start); + start += PAGE_SIZE; + } + + local_irq_restore(flags); +} + +/* + * Delete TLB entry in MMU for a given page (??? address) + * NOTE One TLB entry contains translation for single PAGE + */ + +void local_flush_tlb_page(struct vm_area_struct *vma, unsigned long page) +{ + const unsigned int cpu = smp_processor_id(); + unsigned long flags; + + /* Note that it is critical that interrupts are DISABLED between + * checking the ASID and using it flush the TLB entry + */ + local_irq_save(flags); + + if (asid_mm(vma->vm_mm, cpu) != MM_CTXT_NO_ASID) { + tlb_entry_erase((page & PAGE_MASK) | hw_pid(vma->vm_mm, cpu)); + } + + local_irq_restore(flags); +} + +#ifdef CONFIG_SMP + +struct tlb_args { + struct vm_area_struct *ta_vma; + unsigned long ta_start; + unsigned long ta_end; +}; + +static inline void ipi_flush_tlb_page(void *arg) +{ + struct tlb_args *ta = arg; + + local_flush_tlb_page(ta->ta_vma, ta->ta_start); +} + +static inline void ipi_flush_tlb_range(void *arg) +{ + struct tlb_args *ta = arg; + + local_flush_tlb_range(ta->ta_vma, ta->ta_start, ta->ta_end); +} + +#ifdef CONFIG_TRANSPARENT_HUGEPAGE +static inline void ipi_flush_pmd_tlb_range(void *arg) +{ + struct tlb_args *ta = arg; + + local_flush_pmd_tlb_range(ta->ta_vma, ta->ta_start, ta->ta_end); +} +#endif + +static inline void ipi_flush_tlb_kernel_range(void *arg) +{ + struct tlb_args *ta = (struct tlb_args *)arg; + + local_flush_tlb_kernel_range(ta->ta_start, ta->ta_end); +} + +void flush_tlb_all(void) +{ + on_each_cpu((smp_call_func_t)local_flush_tlb_all, NULL, 1); +} + +void flush_tlb_mm(struct mm_struct *mm) +{ + on_each_cpu_mask(mm_cpumask(mm), (smp_call_func_t)local_flush_tlb_mm, + mm, 1); +} + +void flush_tlb_page(struct vm_area_struct *vma, unsigned long uaddr) +{ + struct tlb_args ta = { + .ta_vma = vma, + .ta_start = uaddr + }; + + on_each_cpu_mask(mm_cpumask(vma->vm_mm), ipi_flush_tlb_page, &ta, 1); +} + +void flush_tlb_range(struct vm_area_struct *vma, unsigned long start, + unsigned long end) +{ + struct tlb_args ta = { + .ta_vma = vma, + .ta_start = start, + .ta_end = end + }; + + on_each_cpu_mask(mm_cpumask(vma->vm_mm), ipi_flush_tlb_range, &ta, 1); +} + +#ifdef CONFIG_TRANSPARENT_HUGEPAGE +void flush_pmd_tlb_range(struct vm_area_struct *vma, unsigned long start, + unsigned long end) +{ + struct tlb_args ta = { + .ta_vma = vma, + .ta_start = start, + .ta_end = end + }; + + on_each_cpu_mask(mm_cpumask(vma->vm_mm), ipi_flush_pmd_tlb_range, &ta, 1); +} +#endif + +void flush_tlb_kernel_range(unsigned long start, unsigned long end) +{ + struct tlb_args ta = { + .ta_start = start, + .ta_end = end + }; + + on_each_cpu(ipi_flush_tlb_kernel_range, &ta, 1); +} +#endif + +/* + * Routine to create a TLB entry + */ +void create_tlb(struct vm_area_struct *vma, unsigned long vaddr, pte_t *ptep) +{ + unsigned long flags; + unsigned int asid_or_sasid, rwx; + unsigned long pd0; + pte_t pd1; + + /* + * create_tlb() assumes that current->mm == vma->mm, since + * -it ASID for TLB entry is fetched from MMU ASID reg (valid for curr) + * -completes the lazy write to SASID reg (again valid for curr tsk) + * + * Removing the assumption involves + * -Using vma->mm->context{ASID,SASID}, as opposed to MMU reg. + * -Fix the TLB paranoid debug code to not trigger false negatives. + * -More importantly it makes this handler inconsistent with fast-path + * TLB Refill handler which always deals with "current" + * + * Lets see the use cases when current->mm != vma->mm and we land here + * 1. execve->copy_strings()->__get_user_pages->handle_mm_fault + * Here VM wants to pre-install a TLB entry for user stack while + * current->mm still points to pre-execve mm (hence the condition). + * However the stack vaddr is soon relocated (randomization) and + * move_page_tables() tries to undo that TLB entry. + * Thus not creating TLB entry is not any worse. + * + * 2. ptrace(POKETEXT) causes a CoW - debugger(current) inserting a + * breakpoint in debugged task. Not creating a TLB now is not + * performance critical. + * + * Both the cases above are not good enough for code churn. + */ + if (current->active_mm != vma->vm_mm) + return; + + local_irq_save(flags); + + tlb_paranoid_check(asid_mm(vma->vm_mm, smp_processor_id()), vaddr); + + vaddr &= PAGE_MASK; + + /* update this PTE credentials */ + pte_val(*ptep) |= (_PAGE_PRESENT | _PAGE_ACCESSED); + + /* Create HW TLB(PD0,PD1) from PTE */ + + /* ASID for this task */ + asid_or_sasid = read_aux_reg(ARC_REG_PID) & 0xff; + + pd0 = vaddr | asid_or_sasid | (pte_val(*ptep) & PTE_BITS_IN_PD0); + + /* + * ARC MMU provides fully orthogonal access bits for K/U mode, + * however Linux only saves 1 set to save PTE real-estate + * Here we convert 3 PTE bits into 6 MMU bits: + * -Kernel only entries have Kr Kw Kx 0 0 0 + * -User entries have mirrored K and U bits + */ + rwx = pte_val(*ptep) & PTE_BITS_RWX; + + if (pte_val(*ptep) & _PAGE_GLOBAL) + rwx <<= 3; /* r w x => Kr Kw Kx 0 0 0 */ + else + rwx |= (rwx << 3); /* r w x => Kr Kw Kx Ur Uw Ux */ + + pd1 = rwx | (pte_val(*ptep) & PTE_BITS_NON_RWX_IN_PD1); + + tlb_entry_insert(pd0, pd1); + + local_irq_restore(flags); +} + +/* + * Called at the end of pagefault, for a userspace mapped page + * -pre-install the corresponding TLB entry into MMU + * -Finalize the delayed D-cache flush of kernel mapping of page due to + * flush_dcache_page(), copy_user_page() + * + * Note that flush (when done) involves both WBACK - so physical page is + * in sync as well as INV - so any non-congruent aliases don't remain + */ +void update_mmu_cache(struct vm_area_struct *vma, unsigned long vaddr_unaligned, + pte_t *ptep) +{ + unsigned long vaddr = vaddr_unaligned & PAGE_MASK; + phys_addr_t paddr = pte_val(*ptep) & PAGE_MASK_PHYS; + struct page *page = pfn_to_page(pte_pfn(*ptep)); + + create_tlb(vma, vaddr, ptep); + + if (page == ZERO_PAGE(0)) { + return; + } + + /* + * Exec page : Independent of aliasing/page-color considerations, + * since icache doesn't snoop dcache on ARC, any dirty + * K-mapping of a code page needs to be wback+inv so that + * icache fetch by userspace sees code correctly. + * !EXEC page: If K-mapping is NOT congruent to U-mapping, flush it + * so userspace sees the right data. + * (Avoids the flush for Non-exec + congruent mapping case) + */ + if ((vma->vm_flags & VM_EXEC) || + addr_not_cache_congruent(paddr, vaddr)) { + + int dirty = !test_and_set_bit(PG_dc_clean, &page->flags); + if (dirty) { + /* wback + inv dcache lines (K-mapping) */ + __flush_dcache_page(paddr, paddr); + + /* invalidate any existing icache lines (U-mapping) */ + if (vma->vm_flags & VM_EXEC) + __inv_icache_page(paddr, vaddr); + } + } +} + +#ifdef CONFIG_TRANSPARENT_HUGEPAGE + +/* + * MMUv4 in HS38x cores supports Super Pages which are basis for Linux THP + * support. + * + * Normal and Super pages can co-exist (ofcourse not overlap) in TLB with a + * new bit "SZ" in TLB page descriptor to distinguish between them. + * Super Page size is configurable in hardware (4K to 16M), but fixed once + * RTL builds. + * + * The exact THP size a Linux configuration will support is a function of: + * - MMU page size (typical 8K, RTL fixed) + * - software page walker address split between PGD:PTE:PFN (typical + * 11:8:13, but can be changed with 1 line) + * So for above default, THP size supported is 8K * (2^8) = 2M + * + * Default Page Walker is 2 levels, PGD:PTE:PFN, which in THP regime + * reduces to 1 level (as PTE is folded into PGD and canonically referred + * to as PMD). + * Thus THP PMD accessors are implemented in terms of PTE (just like sparc) + */ + +void update_mmu_cache_pmd(struct vm_area_struct *vma, unsigned long addr, + pmd_t *pmd) +{ + pte_t pte = __pte(pmd_val(*pmd)); + update_mmu_cache(vma, addr, &pte); +} + +void pgtable_trans_huge_deposit(struct mm_struct *mm, pmd_t *pmdp, + pgtable_t pgtable) +{ + struct list_head *lh = (struct list_head *) pgtable; + + assert_spin_locked(&mm->page_table_lock); + + /* FIFO */ + if (!pmd_huge_pte(mm, pmdp)) + INIT_LIST_HEAD(lh); + else + list_add(lh, (struct list_head *) pmd_huge_pte(mm, pmdp)); + pmd_huge_pte(mm, pmdp) = pgtable; +} + +pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp) +{ + struct list_head *lh; + pgtable_t pgtable; + + assert_spin_locked(&mm->page_table_lock); + + pgtable = pmd_huge_pte(mm, pmdp); + lh = (struct list_head *) pgtable; + if (list_empty(lh)) + pmd_huge_pte(mm, pmdp) = NULL; + else { + pmd_huge_pte(mm, pmdp) = (pgtable_t) lh->next; + list_del(lh); + } + + pte_val(pgtable[0]) = 0; + pte_val(pgtable[1]) = 0; + + return pgtable; +} + +void local_flush_pmd_tlb_range(struct vm_area_struct *vma, unsigned long start, + unsigned long end) +{ + unsigned int cpu; + unsigned long flags; + + local_irq_save(flags); + + cpu = smp_processor_id(); + + if (likely(asid_mm(vma->vm_mm, cpu) != MM_CTXT_NO_ASID)) { + unsigned int asid = hw_pid(vma->vm_mm, cpu); + + /* No need to loop here: this will always be for 1 Huge Page */ + tlb_entry_erase(start | _PAGE_HW_SZ | asid); + } + + local_irq_restore(flags); +} + +#endif + +/* Read the Cache Build Configuration Registers, Decode them and save into + * the cpuinfo structure for later use. + * No Validation is done here, simply read/convert the BCRs + */ +void read_decode_mmu_bcr(void) +{ + struct cpuinfo_arc_mmu *mmu = &cpuinfo_arc700[smp_processor_id()].mmu; + unsigned int tmp; + struct bcr_mmu_1_2 { +#ifdef CONFIG_CPU_BIG_ENDIAN + unsigned int ver:8, ways:4, sets:4, u_itlb:8, u_dtlb:8; +#else + unsigned int u_dtlb:8, u_itlb:8, sets:4, ways:4, ver:8; +#endif + } *mmu2; + + struct bcr_mmu_3 { +#ifdef CONFIG_CPU_BIG_ENDIAN + unsigned int ver:8, ways:4, sets:4, res:3, sasid:1, pg_sz:4, + u_itlb:4, u_dtlb:4; +#else + unsigned int u_dtlb:4, u_itlb:4, pg_sz:4, sasid:1, res:3, sets:4, + ways:4, ver:8; +#endif + } *mmu3; + + struct bcr_mmu_4 { +#ifdef CONFIG_CPU_BIG_ENDIAN + unsigned int ver:8, sasid:1, sz1:4, sz0:4, res:2, pae:1, + n_ways:2, n_entry:2, n_super:2, u_itlb:3, u_dtlb:3; +#else + /* DTLB ITLB JES JE JA */ + unsigned int u_dtlb:3, u_itlb:3, n_super:2, n_entry:2, n_ways:2, + pae:1, res:2, sz0:4, sz1:4, sasid:1, ver:8; +#endif + } *mmu4; + + tmp = read_aux_reg(ARC_REG_MMU_BCR); + mmu->ver = (tmp >> 24); + + if (is_isa_arcompact()) { + if (mmu->ver <= 2) { + mmu2 = (struct bcr_mmu_1_2 *)&tmp; + mmu->pg_sz_k = TO_KB(0x2000); + mmu->sets = 1 << mmu2->sets; + mmu->ways = 1 << mmu2->ways; + mmu->u_dtlb = mmu2->u_dtlb; + mmu->u_itlb = mmu2->u_itlb; + } else { + mmu3 = (struct bcr_mmu_3 *)&tmp; + mmu->pg_sz_k = 1 << (mmu3->pg_sz - 1); + mmu->sets = 1 << mmu3->sets; + mmu->ways = 1 << mmu3->ways; + mmu->u_dtlb = mmu3->u_dtlb; + mmu->u_itlb = mmu3->u_itlb; + mmu->sasid = mmu3->sasid; + } + } else { + mmu4 = (struct bcr_mmu_4 *)&tmp; + mmu->pg_sz_k = 1 << (mmu4->sz0 - 1); + mmu->s_pg_sz_m = 1 << (mmu4->sz1 - 11); + mmu->sets = 64 << mmu4->n_entry; + mmu->ways = mmu4->n_ways * 2; + mmu->u_dtlb = mmu4->u_dtlb * 4; + mmu->u_itlb = mmu4->u_itlb * 4; + mmu->sasid = mmu4->sasid; + pae_exists = mmu->pae = mmu4->pae; + } +} + +char *arc_mmu_mumbojumbo(int cpu_id, char *buf, int len) +{ + int n = 0; + struct cpuinfo_arc_mmu *p_mmu = &cpuinfo_arc700[cpu_id].mmu; + char super_pg[64] = ""; + + if (p_mmu->s_pg_sz_m) + scnprintf(super_pg, 64, "%dM Super Page %s", + p_mmu->s_pg_sz_m, + IS_USED_CFG(CONFIG_TRANSPARENT_HUGEPAGE)); + + n += scnprintf(buf + n, len - n, + "MMU [v%x]\t: %dk PAGE, %sJTLB %d (%dx%d), uDTLB %d, uITLB %d%s%s\n", + p_mmu->ver, p_mmu->pg_sz_k, super_pg, + p_mmu->sets * p_mmu->ways, p_mmu->sets, p_mmu->ways, + p_mmu->u_dtlb, p_mmu->u_itlb, + IS_AVAIL2(p_mmu->pae, ", PAE40 ", CONFIG_ARC_HAS_PAE40)); + + return buf; +} + +int pae40_exist_but_not_enab(void) +{ + return pae_exists && !is_pae40_enabled(); +} + +void arc_mmu_init(void) +{ + struct cpuinfo_arc_mmu *mmu = &cpuinfo_arc700[smp_processor_id()].mmu; + char str[256]; + int compat = 0; + + pr_info("%s", arc_mmu_mumbojumbo(0, str, sizeof(str))); + + /* + * Can't be done in processor.h due to header include dependencies + */ + BUILD_BUG_ON(!IS_ALIGNED((CONFIG_ARC_KVADDR_SIZE << 20), PMD_SIZE)); + + /* + * stack top size sanity check, + * Can't be done in processor.h due to header include dependencies + */ + BUILD_BUG_ON(!IS_ALIGNED(STACK_TOP, PMD_SIZE)); + + /* + * Ensure that MMU features assumed by kernel exist in hardware. + * For older ARC700 cpus, it has to be exact match, since the MMU + * revisions were not backwards compatible (MMUv3 TLB layout changed + * so even if kernel for v2 didn't use any new cmds of v3, it would + * still not work. + * For HS cpus, MMUv4 was baseline and v5 is backwards compatible + * (will run older software). + */ + if (is_isa_arcompact() && mmu->ver == CONFIG_ARC_MMU_VER) + compat = 1; + else if (is_isa_arcv2() && mmu->ver >= CONFIG_ARC_MMU_VER) + compat = 1; + + if (!compat) { + panic("MMU ver %d doesn't match kernel built for %d...\n", + mmu->ver, CONFIG_ARC_MMU_VER); + } + + if (mmu->pg_sz_k != TO_KB(PAGE_SIZE)) + panic("MMU pg size != PAGE_SIZE (%luk)\n", TO_KB(PAGE_SIZE)); + + if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) && + mmu->s_pg_sz_m != TO_MB(HPAGE_PMD_SIZE)) + panic("MMU Super pg size != Linux HPAGE_PMD_SIZE (%luM)\n", + (unsigned long)TO_MB(HPAGE_PMD_SIZE)); + + if (IS_ENABLED(CONFIG_ARC_HAS_PAE40) && !mmu->pae) + panic("Hardware doesn't support PAE40\n"); + + /* Enable the MMU */ + write_aux_reg(ARC_REG_PID, MMU_ENABLE); + + /* In smp we use this reg for interrupt 1 scratch */ +#ifdef ARC_USE_SCRATCH_REG + /* swapper_pg_dir is the pgd for the kernel, used by vmalloc */ + write_aux_reg(ARC_REG_SCRATCH_DATA0, swapper_pg_dir); +#endif + + if (pae40_exist_but_not_enab()) + write_aux_reg(ARC_REG_TLBPD1HI, 0); +} + +/* + * TLB Programmer's Model uses Linear Indexes: 0 to {255, 511} for 128 x {2,4} + * The mapping is Column-first. + * --------------------- ----------- + * |way0|way1|way2|way3| |way0|way1| + * --------------------- ----------- + * [set0] | 0 | 1 | 2 | 3 | | 0 | 1 | + * [set1] | 4 | 5 | 6 | 7 | | 2 | 3 | + * ~ ~ ~ ~ + * [set127] | 508| 509| 510| 511| | 254| 255| + * --------------------- ----------- + * For normal operations we don't(must not) care how above works since + * MMU cmd getIndex(vaddr) abstracts that out. + * However for walking WAYS of a SET, we need to know this + */ +#define SET_WAY_TO_IDX(mmu, set, way) ((set) * mmu->ways + (way)) + +/* Handling of Duplicate PD (TLB entry) in MMU. + * -Could be due to buggy customer tapeouts or obscure kernel bugs + * -MMU complaints not at the time of duplicate PD installation, but at the + * time of lookup matching multiple ways. + * -Ideally these should never happen - but if they do - workaround by deleting + * the duplicate one. + * -Knob to be verbose abt it.(TODO: hook them up to debugfs) + */ +volatile int dup_pd_silent; /* Be silent abt it or complain (default) */ + +void do_tlb_overlap_fault(unsigned long cause, unsigned long address, + struct pt_regs *regs) +{ + struct cpuinfo_arc_mmu *mmu = &cpuinfo_arc700[smp_processor_id()].mmu; + unsigned long flags; + int set, n_ways = mmu->ways; + + n_ways = min(n_ways, 4); + BUG_ON(mmu->ways > 4); + + local_irq_save(flags); + + /* loop thru all sets of TLB */ + for (set = 0; set < mmu->sets; set++) { + + int is_valid, way; + unsigned int pd0[4]; + + /* read out all the ways of current set */ + for (way = 0, is_valid = 0; way < n_ways; way++) { + write_aux_reg(ARC_REG_TLBINDEX, + SET_WAY_TO_IDX(mmu, set, way)); + write_aux_reg(ARC_REG_TLBCOMMAND, TLBRead); + pd0[way] = read_aux_reg(ARC_REG_TLBPD0); + is_valid |= pd0[way] & _PAGE_PRESENT; + pd0[way] &= PAGE_MASK; + } + + /* If all the WAYS in SET are empty, skip to next SET */ + if (!is_valid) + continue; + + /* Scan the set for duplicate ways: needs a nested loop */ + for (way = 0; way < n_ways - 1; way++) { + + int n; + + if (!pd0[way]) + continue; + + for (n = way + 1; n < n_ways; n++) { + if (pd0[way] != pd0[n]) + continue; + + if (!dup_pd_silent) + pr_info("Dup TLB PD0 %08x @ set %d ways %d,%d\n", + pd0[way], set, way, n); + + /* + * clear entry @way and not @n. + * This is critical to our optimised loop + */ + pd0[way] = 0; + write_aux_reg(ARC_REG_TLBINDEX, + SET_WAY_TO_IDX(mmu, set, way)); + __tlb_entry_erase(); + } + } + } + + local_irq_restore(flags); +} + +/*********************************************************************** + * Diagnostic Routines + * -Called from Low Level TLB Handlers if things don;t look good + **********************************************************************/ + +#ifdef CONFIG_ARC_DBG_TLB_PARANOIA + +/* + * Low Level ASM TLB handler calls this if it finds that HW and SW ASIDS + * don't match + */ +void print_asid_mismatch(int mm_asid, int mmu_asid, int is_fast_path) +{ + pr_emerg("ASID Mismatch in %s Path Handler: sw-pid=0x%x hw-pid=0x%x\n", + is_fast_path ? "Fast" : "Slow", mm_asid, mmu_asid); + + __asm__ __volatile__("flag 1"); +} + +void tlb_paranoid_check(unsigned int mm_asid, unsigned long addr) +{ + unsigned int mmu_asid; + + mmu_asid = read_aux_reg(ARC_REG_PID) & 0xff; + + /* + * At the time of a TLB miss/installation + * - HW version needs to match SW version + * - SW needs to have a valid ASID + */ + if (addr < 0x70000000 && + ((mm_asid == MM_CTXT_NO_ASID) || + (mmu_asid != (mm_asid & MM_CTXT_ASID_MASK)))) + print_asid_mismatch(mm_asid, mmu_asid, 0); +} +#endif |