1 files changed, 261 insertions, 0 deletions
diff --git a/arch/powerpc/mm/book3s64/hash_tlb.c b/arch/powerpc/mm/book3s64/hash_tlb.c
new file mode 100644
index 000000000000..4a70d8dd39cd
--- /dev/null
+++ b/arch/powerpc/mm/book3s64/hash_tlb.c
@@ -0,0 +1,261 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * This file contains the routines for flushing entries from the
+ * TLB and MMU hash table.
+ *
+ *  Derived from arch/ppc64/mm/init.c:
+ *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
+ *
+ *  Modifications by Paul Mackerras (PowerMac) (paulus@cs.anu.edu.au)
+ *  and Cort Dougan (PReP) (cort@cs.nmt.edu)
+ *    Copyright (C) 1996 Paul Mackerras
+ *
+ *  Derived from "arch/i386/mm/init.c"
+ *    Copyright (C) 1991, 1992, 1993, 1994  Linus Torvalds
+ *
+ *  Dave Engebretsen <engebret@us.ibm.com>
+ *      Rework for PPC64 port.
+ */
+
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/percpu.h>
+#include <linux/hardirq.h>
+#include <asm/pgalloc.h>
+#include <asm/tlbflush.h>
+#include <asm/tlb.h>
+#include <asm/bug.h>
+#include <asm/pte-walk.h>
+
+
+#include <trace/events/thp.h>
+
+DEFINE_PER_CPU(struct ppc64_tlb_batch, ppc64_tlb_batch);
+
+/*
+ * A linux PTE was changed and the corresponding hash table entry
+ * neesd to be flushed. This function will either perform the flush
+ * immediately or will batch it up if the current CPU has an active
+ * batch on it.
+ */
+void hpte_need_flush(struct mm_struct *mm, unsigned long addr,
+		     pte_t *ptep, unsigned long pte, int huge)
+{
+	unsigned long vpn;
+	struct ppc64_tlb_batch *batch = &get_cpu_var(ppc64_tlb_batch);
+	unsigned long vsid;
+	unsigned int psize;
+	int ssize;
+	real_pte_t rpte;
+	int i, offset;
+
+	i = batch->index;
+
+	/*
+	 * Get page size (maybe move back to caller).
+	 *
+	 * NOTE: when using special 64K mappings in 4K environment like
+	 * for SPEs, we obtain the page size from the slice, which thus
+	 * must still exist (and thus the VMA not reused) at the time
+	 * of this call
+	 */
+	if (huge) {
+#ifdef CONFIG_HUGETLB_PAGE
+		psize = get_slice_psize(mm, addr);
+		/* Mask the address for the correct page size */
+		addr &= ~((1UL << mmu_psize_defs[psize].shift) - 1);
+		if (unlikely(psize == MMU_PAGE_16G))
+			offset = PTRS_PER_PUD;
+		else
+			offset = PTRS_PER_PMD;
+#else
+		BUG();
+		psize = pte_pagesize_index(mm, addr, pte); /* shutup gcc */
+#endif
+	} else {
+		psize = pte_pagesize_index(mm, addr, pte);
+		/*
+		 * Mask the address for the standard page size.  If we
+		 * have a 64k page kernel, but the hardware does not
+		 * support 64k pages, this might be different from the
+		 * hardware page size encoded in the slice table.
+		 */
+		addr &= PAGE_MASK;
+		offset = PTRS_PER_PTE;
+	}
+
+
+	/* Build full vaddr */
+	if (!is_kernel_addr(addr)) {
+		ssize = user_segment_size(addr);
+		vsid = get_user_vsid(&mm->context, addr, ssize);
+	} else {
+		vsid = get_kernel_vsid(addr, mmu_kernel_ssize);
+		ssize = mmu_kernel_ssize;
+	}
+	WARN_ON(vsid == 0);
+	vpn = hpt_vpn(addr, vsid, ssize);
+	rpte = __real_pte(__pte(pte), ptep, offset);
+
+	/*
+	 * Check if we have an active batch on this CPU. If not, just
+	 * flush now and return.
+	 */
+	if (!batch->active) {
+		flush_hash_page(vpn, rpte, psize, ssize, mm_is_thread_local(mm));
+		put_cpu_var(ppc64_tlb_batch);
+		return;
+	}
+
+	/*
+	 * This can happen when we are in the middle of a TLB batch and
+	 * we encounter memory pressure (eg copy_page_range when it tries
+	 * to allocate a new pte). If we have to reclaim memory and end
+	 * up scanning and resetting referenced bits then our batch context
+	 * will change mid stream.
+	 *
+	 * We also need to ensure only one page size is present in a given
+	 * batch
+	 */
+	if (i != 0 && (mm != batch->mm || batch->psize != psize ||
+		       batch->ssize != ssize)) {
+		__flush_tlb_pending(batch);
+		i = 0;
+	}
+	if (i == 0) {
+		batch->mm = mm;
+		batch->psize = psize;
+		batch->ssize = ssize;
+	}
+	batch->pte[i] = rpte;
+	batch->vpn[i] = vpn;
+	batch->index = ++i;
+	if (i >= PPC64_TLB_BATCH_NR)
+		__flush_tlb_pending(batch);
+	put_cpu_var(ppc64_tlb_batch);
+}
+
+/*
+ * This function is called when terminating an mmu batch or when a batch
+ * is full. It will perform the flush of all the entries currently stored
+ * in a batch.
+ *
+ * Must be called from within some kind of spinlock/non-preempt region...
+ */
+void __flush_tlb_pending(struct ppc64_tlb_batch *batch)
+{
+	int i, local;
+
+	i = batch->index;
+	local = mm_is_thread_local(batch->mm);
+	if (i == 1)
+		flush_hash_page(batch->vpn[0], batch->pte[0],
+				batch->psize, batch->ssize, local);
+	else
+		flush_hash_range(i, local);
+	batch->index = 0;
+}
+
+void hash__tlb_flush(struct mmu_gather *tlb)
+{
+	struct ppc64_tlb_batch *tlbbatch = &get_cpu_var(ppc64_tlb_batch);
+
+	/*
+	 * If there's a TLB batch pending, then we must flush it because the
+	 * pages are going to be freed and we really don't want to have a CPU
+	 * access a freed page because it has a stale TLB
+	 */
+	if (tlbbatch->index)
+		__flush_tlb_pending(tlbbatch);
+
+	put_cpu_var(ppc64_tlb_batch);
+}
+
+/**
+ * __flush_hash_table_range - Flush all HPTEs for a given address range
+ *                            from the hash table (and the TLB). But keeps
+ *                            the linux PTEs intact.
+ *
+ * @mm		: mm_struct of the target address space (generally init_mm)
+ * @start	: starting address
+ * @end         : ending address (not included in the flush)
+ *
+ * This function is mostly to be used by some IO hotplug code in order
+ * to remove all hash entries from a given address range used to map IO
+ * space on a removed PCI-PCI bidge without tearing down the full mapping
+ * since 64K pages may overlap with other bridges when using 64K pages
+ * with 4K HW pages on IO space.
+ *
+ * Because of that usage pattern, it is implemented for small size rather
+ * than speed.
+ */
+void __flush_hash_table_range(struct mm_struct *mm, unsigned long start,
+			      unsigned long end)
+{
+	bool is_thp;
+	int hugepage_shift;
+	unsigned long flags;
+
+	start = _ALIGN_DOWN(start, PAGE_SIZE);
+	end = _ALIGN_UP(end, PAGE_SIZE);
+
+	BUG_ON(!mm->pgd);
+
+	/*
+	 * Note: Normally, we should only ever use a batch within a
+	 * PTE locked section. This violates the rule, but will work
+	 * since we don't actually modify the PTEs, we just flush the
+	 * hash while leaving the PTEs intact (including their reference
+	 * to being hashed). This is not the most performance oriented
+	 * way to do things but is fine for our needs here.
+	 */
+	local_irq_save(flags);
+	arch_enter_lazy_mmu_mode();
+	for (; start < end; start += PAGE_SIZE) {
+		pte_t *ptep = find_current_mm_pte(mm->pgd, start, &is_thp,
+						  &hugepage_shift);
+		unsigned long pte;
+
+		if (ptep == NULL)
+			continue;
+		pte = pte_val(*ptep);
+		if (is_thp)
+			trace_hugepage_invalidate(start, pte);
+		if (!(pte & H_PAGE_HASHPTE))
+			continue;
+		if (unlikely(is_thp))
+			hpte_do_hugepage_flush(mm, start, (pmd_t *)ptep, pte);
+		else
+			hpte_need_flush(mm, start, ptep, pte, hugepage_shift);
+	}
+	arch_leave_lazy_mmu_mode();
+	local_irq_restore(flags);
+}
+
+void flush_tlb_pmd_range(struct mm_struct *mm, pmd_t *pmd, unsigned long addr)
+{
+	pte_t *pte;
+	pte_t *start_pte;
+	unsigned long flags;
+
+	addr = _ALIGN_DOWN(addr, PMD_SIZE);
+	/*
+	 * Note: Normally, we should only ever use a batch within a
+	 * PTE locked section. This violates the rule, but will work
+	 * since we don't actually modify the PTEs, we just flush the
+	 * hash while leaving the PTEs intact (including their reference
+	 * to being hashed). This is not the most performance oriented
+	 * way to do things but is fine for our needs here.
+	 */
+	local_irq_save(flags);
+	arch_enter_lazy_mmu_mode();
+	start_pte = pte_offset_map(pmd, addr);
+	for (pte = start_pte; pte < start_pte + PTRS_PER_PTE; pte++) {
+		unsigned long pteval = pte_val(*pte);
+		if (pteval & H_PAGE_HASHPTE)
+			hpte_need_flush(mm, addr, pte, pteval, 0);
+		addr += PAGE_SIZE;
+	}
+	arch_leave_lazy_mmu_mode();
+	local_irq_restore(flags);
+}