File-copy from v4.4.100
This is the result of 'cp' from a linux-stable tree with the 'v4.4.100'
tag checked out (commit 26d6298789e695c9f627ce49a7bbd2286405798a) on
git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Please refer to that tree for all history prior to this point.
Change-Id: I8a9ee2aea93cd29c52c847d0ce33091a73ae6afe
diff --git a/arch/arc/mm/tlb.c b/arch/arc/mm/tlb.c
new file mode 100644
index 0000000..97e9582
--- /dev/null
+++ b/arch/arc/mm/tlb.c
@@ -0,0 +1,973 @@
+/*
+ * TLB Management (flush/create/diagnostics) for ARC700
+ *
+ * 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: 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 explict 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 seperated 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() doesnt 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 <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 thrasing 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;
+
+/*
+ * 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);
+}
+
+#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);
+ }
+}
+
+/****************************************************************************
+ * ARC700 MMU caches recently used J-TLB entries (RAM) as uTLBs (FLOPs)
+ *
+ * New IVUTLB cmd in MMU v2 explictly invalidates the uTLB
+ *
+ * utlb_invalidate ( )
+ * -For v2 MMU calls Flush uTLB Cmd
+ * -For v1 MMU does nothing (except for Metal Fix v1 MMU)
+ * This is because in v1 TLBWrite itself invalidate uTLBs
+ ***************************************************************************/
+
+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 didnt exist in MMU.
+ * The Workround was to set Index reg with some valid value, prior to
+ * flush. This was fixed in MMU v3 hence not needed any more
+ */
+ 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
+
+}
+
+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 doesnt 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 utlb_invalidate(void)
+{
+ /* No need since uTLB is always in sync with JTLB */
+}
+
+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, TLBWrite);
+ }
+
+ 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, TLBWrite);
+ }
+ }
+
+ utlb_invalidate();
+
+ local_irq_restore(flags);
+}
+
+/*
+ * Flush the entrie 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 explictly
+ */
+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;
+ }
+ }
+
+ utlb_invalidate();
+
+ 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;
+ }
+
+ utlb_invalidate();
+
+ 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));
+ utlb_invalidate();
+ }
+
+ 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;
+ 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 desciptor to distinguish between them.
+ * Super Page size is configurable in hardware (4K to 16M), but fixed once
+ * RTL builds.
+ *
+ * The exact THP size a Linx 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 Confuration 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 (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 if (mmu->ver == 3) {
+ 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;
+ 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;
+}
+
+void arc_mmu_init(void)
+{
+ char str[256];
+ struct cpuinfo_arc_mmu *mmu = &cpuinfo_arc700[smp_processor_id()].mmu;
+
+ printk(arc_mmu_mumbojumbo(0, str, sizeof(str)));
+
+ /* For efficiency sake, kernel is compile time built for a MMU ver
+ * This must match the hardware it is running on.
+ * Linux built for MMU V2, if run on MMU V1 will break down because V1
+ * hardware doesn't understand cmds such as WriteNI, or IVUTLB
+ * On the other hand, Linux built for V1 if run on MMU V2 will do
+ * un-needed workarounds to prevent memcpy thrashing.
+ * Similarly MMU V3 has new features which won't work on older MMU
+ */
+ if (mmu->ver != CONFIG_ARC_MMU_VER) {
+ 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 */
+#ifndef CONFIG_SMP
+ /* swapper_pg_dir is the pgd for the kernel, used by vmalloc */
+ write_aux_reg(ARC_REG_SCRATCH_DATA0, swapper_pg_dir);
+#endif
+}
+
+/*
+ * 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 slient 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 int pd0[mmu->ways];
+ unsigned long flags;
+ int set;
+
+ local_irq_save(flags);
+
+ /* loop thru all sets of TLB */
+ for (set = 0; set < mmu->sets; set++) {
+
+ int is_valid, way;
+
+ /* read out all the ways of current set */
+ for (way = 0, is_valid = 0; way < mmu->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 < mmu->ways - 1; way++) {
+
+ int n;
+
+ if (!pd0[way])
+ continue;
+
+ for (n = way + 1; n < mmu->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 Hanlders 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