Fixed MTP to work with TWRP

arch/frv/mm/pgalloc.c

@@ -0,0 +1,157 @@
+/* pgalloc.c: page directory & page table allocation
+ *
+ * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/sched.h>
+#include <linux/gfp.h>
+#include <linux/mm.h>
+#include <linux/highmem.h>
+#include <linux/quicklist.h>
+#include <asm/pgalloc.h>
+#include <asm/page.h>
+#include <asm/cacheflush.h>
+
+pgd_t swapper_pg_dir[PTRS_PER_PGD] __attribute__((aligned(PAGE_SIZE)));
+
+pte_t *pte_alloc_one_kernel(struct mm_struct *mm, unsigned long address)
+{
+	pte_t *pte = (pte_t *)__get_free_page(GFP_KERNEL|__GFP_REPEAT);
+	if (pte)
+		clear_page(pte);
+	return pte;
+}
+
+pgtable_t pte_alloc_one(struct mm_struct *mm, unsigned long address)
+{
+	struct page *page;
+
+#ifdef CONFIG_HIGHPTE
+	page = alloc_pages(GFP_KERNEL|__GFP_HIGHMEM|__GFP_REPEAT, 0);
+#else
+	page = alloc_pages(GFP_KERNEL|__GFP_REPEAT, 0);
+#endif
+	if (!page)
+		return NULL;
+
+	clear_highpage(page);
+	if (!pgtable_page_ctor(page)) {
+		__free_page(page);
+		return NULL;
+	}
+	flush_dcache_page(page);
+	return page;
+}
+
+void __set_pmd(pmd_t *pmdptr, unsigned long pmd)
+{
+	unsigned long *__ste_p = pmdptr->ste;
+	int loop;
+
+	if (!pmd) {
+		memset(__ste_p, 0, PME_SIZE);
+	}
+	else {
+		BUG_ON(pmd & (0x3f00 | xAMPRx_SS | 0xe));
+
+		for (loop = PME_SIZE; loop > 0; loop -= 4) {
+			*__ste_p++ = pmd;
+			pmd += __frv_PT_SIZE;
+		}
+	}
+
+	frv_dcache_writeback((unsigned long) pmdptr, (unsigned long) (pmdptr + 1));
+}
+
+/*
+ * List of all pgd's needed for non-PAE so it can invalidate entries
+ * in both cached and uncached pgd's; not needed for PAE since the
+ * kernel pmd is shared. If PAE were not to share the pmd a similar
+ * tactic would be needed. This is essentially codepath-based locking
+ * against pageattr.c; it is the unique case in which a valid change
+ * of kernel pagetables can't be lazily synchronized by vmalloc faults.
+ * vmalloc faults work because attached pagetables are never freed.
+ * If the locking proves to be non-performant, a ticketing scheme with
+ * checks at dup_mmap(), exec(), and other mmlist addition points
+ * could be used. The locking scheme was chosen on the basis of
+ * manfred's recommendations and having no core impact whatsoever.
+ * -- nyc
+ */
+DEFINE_SPINLOCK(pgd_lock);
+struct page *pgd_list;
+
+static inline void pgd_list_add(pgd_t *pgd)
+{
+	struct page *page = virt_to_page(pgd);
+	page->index = (unsigned long) pgd_list;
+	if (pgd_list)
+		set_page_private(pgd_list, (unsigned long) &page->index);
+	pgd_list = page;
+	set_page_private(page, (unsigned long)&pgd_list);
+}
+
+static inline void pgd_list_del(pgd_t *pgd)
+{
+	struct page *next, **pprev, *page = virt_to_page(pgd);
+	next = (struct page *) page->index;
+	pprev = (struct page **) page_private(page);
+	*pprev = next;
+	if (next)
+		set_page_private(next, (unsigned long) pprev);
+}
+
+void pgd_ctor(void *pgd)
+{
+	unsigned long flags;
+
+	if (PTRS_PER_PMD == 1)
+		spin_lock_irqsave(&pgd_lock, flags);
+
+	memcpy((pgd_t *) pgd + USER_PGDS_IN_LAST_PML4,
+	       swapper_pg_dir + USER_PGDS_IN_LAST_PML4,
+	       (PTRS_PER_PGD - USER_PGDS_IN_LAST_PML4) * sizeof(pgd_t));
+
+	if (PTRS_PER_PMD > 1)
+		return;
+
+	pgd_list_add(pgd);
+	spin_unlock_irqrestore(&pgd_lock, flags);
+	memset(pgd, 0, USER_PGDS_IN_LAST_PML4 * sizeof(pgd_t));
+}
+
+/* never called when PTRS_PER_PMD > 1 */
+void pgd_dtor(void *pgd)
+{
+	unsigned long flags; /* can be called from interrupt context */
+
+	spin_lock_irqsave(&pgd_lock, flags);
+	pgd_list_del(pgd);
+	spin_unlock_irqrestore(&pgd_lock, flags);
+}
+
+pgd_t *pgd_alloc(struct mm_struct *mm)
+{
+	return quicklist_alloc(0, GFP_KERNEL, pgd_ctor);
+}
+
+void pgd_free(struct mm_struct *mm, pgd_t *pgd)
+{
+	/* in the non-PAE case, clear_page_tables() clears user pgd entries */
+ 	quicklist_free(0, pgd_dtor, pgd);
+}
+
+void __init pgtable_cache_init(void)
+{
+}
+
+void check_pgt_cache(void)
+{
+	quicklist_trim(0, pgd_dtor, 25, 16);
+}
+