1 files changed, 408 insertions, 0 deletions
diff --git a/arch/arm/mm/flush.c b/arch/arm/mm/flush.c
new file mode 100644
index 0000000000..d19d140a10
--- /dev/null
+++ b/arch/arm/mm/flush.c
@@ -0,0 +1,408 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *  linux/arch/arm/mm/flush.c
+ *
+ *  Copyright (C) 1995-2002 Russell King
+ */
+#include <linux/module.h>
+#include <linux/mm.h>
+#include <linux/pagemap.h>
+#include <linux/highmem.h>
+
+#include <asm/cacheflush.h>
+#include <asm/cachetype.h>
+#include <asm/highmem.h>
+#include <asm/smp_plat.h>
+#include <asm/tlbflush.h>
+#include <linux/hugetlb.h>
+
+#include "mm.h"
+
+#ifdef CONFIG_ARM_HEAVY_MB
+void (*soc_mb)(void);
+
+void arm_heavy_mb(void)
+{
+#ifdef CONFIG_OUTER_CACHE_SYNC
+	if (outer_cache.sync)
+		outer_cache.sync();
+#endif
+	if (soc_mb)
+		soc_mb();
+}
+EXPORT_SYMBOL(arm_heavy_mb);
+#endif
+
+#ifdef CONFIG_CPU_CACHE_VIPT
+
+static void flush_pfn_alias(unsigned long pfn, unsigned long vaddr)
+{
+	unsigned long to = FLUSH_ALIAS_START + (CACHE_COLOUR(vaddr) << PAGE_SHIFT);
+	const int zero = 0;
+
+	set_top_pte(to, pfn_pte(pfn, PAGE_KERNEL));
+
+	asm(	"mcrr	p15, 0, %1, %0, c14\n"
+	"	mcr	p15, 0, %2, c7, c10, 4"
+	    :
+	    : "r" (to), "r" (to + PAGE_SIZE - 1), "r" (zero)
+	    : "cc");
+}
+
+static void flush_icache_alias(unsigned long pfn, unsigned long vaddr, unsigned long len)
+{
+	unsigned long va = FLUSH_ALIAS_START + (CACHE_COLOUR(vaddr) << PAGE_SHIFT);
+	unsigned long offset = vaddr & (PAGE_SIZE - 1);
+	unsigned long to;
+
+	set_top_pte(va, pfn_pte(pfn, PAGE_KERNEL));
+	to = va + offset;
+	flush_icache_range(to, to + len);
+}
+
+void flush_cache_mm(struct mm_struct *mm)
+{
+	if (cache_is_vivt()) {
+		vivt_flush_cache_mm(mm);
+		return;
+	}
+
+	if (cache_is_vipt_aliasing()) {
+		asm(	"mcr	p15, 0, %0, c7, c14, 0\n"
+		"	mcr	p15, 0, %0, c7, c10, 4"
+		    :
+		    : "r" (0)
+		    : "cc");
+	}
+}
+
+void flush_cache_range(struct vm_area_struct *vma, unsigned long start, unsigned long end)
+{
+	if (cache_is_vivt()) {
+		vivt_flush_cache_range(vma, start, end);
+		return;
+	}
+
+	if (cache_is_vipt_aliasing()) {
+		asm(	"mcr	p15, 0, %0, c7, c14, 0\n"
+		"	mcr	p15, 0, %0, c7, c10, 4"
+		    :
+		    : "r" (0)
+		    : "cc");
+	}
+
+	if (vma->vm_flags & VM_EXEC)
+		__flush_icache_all();
+}
+
+void flush_cache_pages(struct vm_area_struct *vma, unsigned long user_addr, unsigned long pfn, unsigned int nr)
+{
+	if (cache_is_vivt()) {
+		vivt_flush_cache_pages(vma, user_addr, pfn, nr);
+		return;
+	}
+
+	if (cache_is_vipt_aliasing()) {
+		flush_pfn_alias(pfn, user_addr);
+		__flush_icache_all();
+	}
+
+	if (vma->vm_flags & VM_EXEC && icache_is_vivt_asid_tagged())
+		__flush_icache_all();
+}
+
+#else
+#define flush_pfn_alias(pfn,vaddr)		do { } while (0)
+#define flush_icache_alias(pfn,vaddr,len)	do { } while (0)
+#endif
+
+#define FLAG_PA_IS_EXEC 1
+#define FLAG_PA_CORE_IN_MM 2
+
+static void flush_ptrace_access_other(void *args)
+{
+	__flush_icache_all();
+}
+
+static inline
+void __flush_ptrace_access(struct page *page, unsigned long uaddr, void *kaddr,
+			   unsigned long len, unsigned int flags)
+{
+	if (cache_is_vivt()) {
+		if (flags & FLAG_PA_CORE_IN_MM) {
+			unsigned long addr = (unsigned long)kaddr;
+			__cpuc_coherent_kern_range(addr, addr + len);
+		}
+		return;
+	}
+
+	if (cache_is_vipt_aliasing()) {
+		flush_pfn_alias(page_to_pfn(page), uaddr);
+		__flush_icache_all();
+		return;
+	}
+
+	/* VIPT non-aliasing D-cache */
+	if (flags & FLAG_PA_IS_EXEC) {
+		unsigned long addr = (unsigned long)kaddr;
+		if (icache_is_vipt_aliasing())
+			flush_icache_alias(page_to_pfn(page), uaddr, len);
+		else
+			__cpuc_coherent_kern_range(addr, addr + len);
+		if (cache_ops_need_broadcast())
+			smp_call_function(flush_ptrace_access_other,
+					  NULL, 1);
+	}
+}
+
+static
+void flush_ptrace_access(struct vm_area_struct *vma, struct page *page,
+			 unsigned long uaddr, void *kaddr, unsigned long len)
+{
+	unsigned int flags = 0;
+	if (cpumask_test_cpu(smp_processor_id(), mm_cpumask(vma->vm_mm)))
+		flags |= FLAG_PA_CORE_IN_MM;
+	if (vma->vm_flags & VM_EXEC)
+		flags |= FLAG_PA_IS_EXEC;
+	__flush_ptrace_access(page, uaddr, kaddr, len, flags);
+}
+
+void flush_uprobe_xol_access(struct page *page, unsigned long uaddr,
+			     void *kaddr, unsigned long len)
+{
+	unsigned int flags = FLAG_PA_CORE_IN_MM|FLAG_PA_IS_EXEC;
+
+	__flush_ptrace_access(page, uaddr, kaddr, len, flags);
+}
+
+/*
+ * Copy user data from/to a page which is mapped into a different
+ * processes address space.  Really, we want to allow our "user
+ * space" model to handle this.
+ *
+ * Note that this code needs to run on the current CPU.
+ */
+void copy_to_user_page(struct vm_area_struct *vma, struct page *page,
+		       unsigned long uaddr, void *dst, const void *src,
+		       unsigned long len)
+{
+#ifdef CONFIG_SMP
+	preempt_disable();
+#endif
+	memcpy(dst, src, len);
+	flush_ptrace_access(vma, page, uaddr, dst, len);
+#ifdef CONFIG_SMP
+	preempt_enable();
+#endif
+}
+
+void __flush_dcache_folio(struct address_space *mapping, struct folio *folio)
+{
+	/*
+	 * Writeback any data associated with the kernel mapping of this
+	 * page.  This ensures that data in the physical page is mutually
+	 * coherent with the kernels mapping.
+	 */
+	if (!folio_test_highmem(folio)) {
+		__cpuc_flush_dcache_area(folio_address(folio),
+					folio_size(folio));
+	} else {
+		unsigned long i;
+		if (cache_is_vipt_nonaliasing()) {
+			for (i = 0; i < folio_nr_pages(folio); i++) {
+				void *addr = kmap_local_folio(folio,
+								i * PAGE_SIZE);
+				__cpuc_flush_dcache_area(addr, PAGE_SIZE);
+				kunmap_local(addr);
+			}
+		} else {
+			for (i = 0; i < folio_nr_pages(folio); i++) {
+				void *addr = kmap_high_get(folio_page(folio, i));
+				if (addr) {
+					__cpuc_flush_dcache_area(addr, PAGE_SIZE);
+					kunmap_high(folio_page(folio, i));
+				}
+			}
+		}
+	}
+
+	/*
+	 * If this is a page cache page, and we have an aliasing VIPT cache,
+	 * we only need to do one flush - which would be at the relevant
+	 * userspace colour, which is congruent with page->index.
+	 */
+	if (mapping && cache_is_vipt_aliasing())
+		flush_pfn_alias(folio_pfn(folio), folio_pos(folio));
+}
+
+static void __flush_dcache_aliases(struct address_space *mapping, struct folio *folio)
+{
+	struct mm_struct *mm = current->active_mm;
+	struct vm_area_struct *vma;
+	pgoff_t pgoff, pgoff_end;
+
+	/*
+	 * There are possible user space mappings of this page:
+	 * - VIVT cache: we need to also write back and invalidate all user
+	 *   data in the current VM view associated with this page.
+	 * - aliasing VIPT: we only need to find one mapping of this page.
+	 */
+	pgoff = folio->index;
+	pgoff_end = pgoff + folio_nr_pages(folio) - 1;
+
+	flush_dcache_mmap_lock(mapping);
+	vma_interval_tree_foreach(vma, &mapping->i_mmap, pgoff, pgoff_end) {
+		unsigned long start, offset, pfn;
+		unsigned int nr;
+
+		/*
+		 * If this VMA is not in our MM, we can ignore it.
+		 */
+		if (vma->vm_mm != mm)
+			continue;
+		if (!(vma->vm_flags & VM_MAYSHARE))
+			continue;
+
+		start = vma->vm_start;
+		pfn = folio_pfn(folio);
+		nr = folio_nr_pages(folio);
+		offset = pgoff - vma->vm_pgoff;
+		if (offset > -nr) {
+			pfn -= offset;
+			nr += offset;
+		} else {
+			start += offset * PAGE_SIZE;
+		}
+		if (start + nr * PAGE_SIZE > vma->vm_end)
+			nr = (vma->vm_end - start) / PAGE_SIZE;
+
+		flush_cache_pages(vma, start, pfn, nr);
+	}
+	flush_dcache_mmap_unlock(mapping);
+}
+
+#if __LINUX_ARM_ARCH__ >= 6
+void __sync_icache_dcache(pte_t pteval)
+{
+	unsigned long pfn;
+	struct folio *folio;
+	struct address_space *mapping;
+
+	if (cache_is_vipt_nonaliasing() && !pte_exec(pteval))
+		/* only flush non-aliasing VIPT caches for exec mappings */
+		return;
+	pfn = pte_pfn(pteval);
+	if (!pfn_valid(pfn))
+		return;
+
+	folio = page_folio(pfn_to_page(pfn));
+	if (cache_is_vipt_aliasing())
+		mapping = folio_flush_mapping(folio);
+	else
+		mapping = NULL;
+
+	if (!test_and_set_bit(PG_dcache_clean, &folio->flags))
+		__flush_dcache_folio(mapping, folio);
+
+	if (pte_exec(pteval))
+		__flush_icache_all();
+}
+#endif
+
+/*
+ * Ensure cache coherency between kernel mapping and userspace mapping
+ * of this page.
+ *
+ * We have three cases to consider:
+ *  - VIPT non-aliasing cache: fully coherent so nothing required.
+ *  - VIVT: fully aliasing, so we need to handle every alias in our
+ *          current VM view.
+ *  - VIPT aliasing: need to handle one alias in our current VM view.
+ *
+ * If we need to handle aliasing:
+ *  If the page only exists in the page cache and there are no user
+ *  space mappings, we can be lazy and remember that we may have dirty
+ *  kernel cache lines for later.  Otherwise, we assume we have
+ *  aliasing mappings.
+ *
+ * Note that we disable the lazy flush for SMP configurations where
+ * the cache maintenance operations are not automatically broadcasted.
+ */
+void flush_dcache_folio(struct folio *folio)
+{
+	struct address_space *mapping;
+
+	/*
+	 * The zero page is never written to, so never has any dirty
+	 * cache lines, and therefore never needs to be flushed.
+	 */
+	if (is_zero_pfn(folio_pfn(folio)))
+		return;
+
+	if (!cache_ops_need_broadcast() && cache_is_vipt_nonaliasing()) {
+		if (test_bit(PG_dcache_clean, &folio->flags))
+			clear_bit(PG_dcache_clean, &folio->flags);
+		return;
+	}
+
+	mapping = folio_flush_mapping(folio);
+
+	if (!cache_ops_need_broadcast() &&
+	    mapping && !folio_mapped(folio))
+		clear_bit(PG_dcache_clean, &folio->flags);
+	else {
+		__flush_dcache_folio(mapping, folio);
+		if (mapping && cache_is_vivt())
+			__flush_dcache_aliases(mapping, folio);
+		else if (mapping)
+			__flush_icache_all();
+		set_bit(PG_dcache_clean, &folio->flags);
+	}
+}
+EXPORT_SYMBOL(flush_dcache_folio);
+
+void flush_dcache_page(struct page *page)
+{
+	flush_dcache_folio(page_folio(page));
+}
+EXPORT_SYMBOL(flush_dcache_page);
+/*
+ * Flush an anonymous page so that users of get_user_pages()
+ * can safely access the data.  The expected sequence is:
+ *
+ *  get_user_pages()
+ *    -> flush_anon_page
+ *  memcpy() to/from page
+ *  if written to page, flush_dcache_page()
+ */
+void __flush_anon_page(struct vm_area_struct *vma, struct page *page, unsigned long vmaddr);
+void __flush_anon_page(struct vm_area_struct *vma, struct page *page, unsigned long vmaddr)
+{
+	unsigned long pfn;
+
+	/* VIPT non-aliasing caches need do nothing */
+	if (cache_is_vipt_nonaliasing())
+		return;
+
+	/*
+	 * Write back and invalidate userspace mapping.
+	 */
+	pfn = page_to_pfn(page);
+	if (cache_is_vivt()) {
+		flush_cache_page(vma, vmaddr, pfn);
+	} else {
+		/*
+		 * For aliasing VIPT, we can flush an alias of the
+		 * userspace address only.
+		 */
+		flush_pfn_alias(pfn, vmaddr);
+		__flush_icache_all();
+	}
+
+	/*
+	 * Invalidate kernel mapping.  No data should be contained
+	 * in this mapping of the page.  FIXME: this is overkill
+	 * since we actually ask for a write-back and invalidate.
+	 */
+	__cpuc_flush_dcache_area(page_address(page), PAGE_SIZE);
+}