Revert "[ARM] mm: add page allocator for modifying cache attributes"

This reverts commit 54d414570432ce07fa1a14b657f53bed752e3d7e.

Change-Id: I8e5cf6ef3555129da9741ef52a1e6a3a772ad588
Signed-off-by: Gary King <gking@nvidia.com>

3 files changed, 0 insertions, 151 deletions

diff --git a/arch/arm/mm/Kconfig b/arch/arm/mm/Kconfig
index 122d88e073d6..88633fe01a5d 100644
--- a/arch/arm/mm/Kconfig
+++ b/arch/arm/mm/Kconfig
@@ -864,29 +864,6 @@ config ARM_L1_CACHE_SHIFT
 	default 6 if ARM_L1_CACHE_SHIFT_6
 	default 5
 
-config ARM_ATTRIB_ALLOCATOR
-	bool "Support custom cache attribute allocations in low memory"
-	select ARCH_LOWMEM_IN_PTES if (CPU_V7)
-	depends on MMU && !CPU_CACHE_VIVT
-	help
-	  Historically, the kernel has only reserved a small region
-	  of physical memory for uncached access, and relied on
-	  explicit cache maintenance for ensuring coherency between
-	  the CPU and DMA.
-
-	  However, many recent systems support mapping discontiguous
-	  physical pages into contiguous DMA addresses (so-called
-	  system MMUs). For some DMA clients (notably graphics and
-	  multimedia engines), performing explict cache maintenance
-	  between CPU and DMA mappings can be prohibitively expensive,
-	  and since ARMv7, mapping the same physical page with different
-	  cache attributes is disallowed and has unpredictable behavior.
-
-	  Say 'Y' here to include page allocation support with explicit
-	  cache attributes; on ARMv7 systems this will also force the
-	  kernel's page tables to be mapped using page tables rather
-	  than sections.
-
 config ARM_DMA_MEM_BUFFERABLE
 	bool "Use non-cacheable memory for DMA" if (CPU_V6 || CPU_V6K) && !CPU_V7
 	depends on !(MACH_REALVIEW_PB1176 || REALVIEW_EB_ARM11MP || \
diff --git a/arch/arm/mm/Makefile b/arch/arm/mm/Makefile
index 2766c8b1a30c..bca7e61928c7 100644
--- a/arch/arm/mm/Makefile
+++ b/arch/arm/mm/Makefile
@@ -12,8 +12,6 @@ ifneq ($(CONFIG_MMU),y)
 obj-y				+= nommu.o
 endif
 
-obj-$(CONFIG_ARM_ATTRIB_ALLOCATOR) += attrib_alloc.o
-
 obj-$(CONFIG_MODULES)		+= proc-syms.o
 
 obj-$(CONFIG_ALIGNMENT_TRAP)	+= alignment.o
diff --git a/arch/arm/mm/attrib_alloc.c b/arch/arm/mm/attrib_alloc.c
deleted file mode 100644
index 73be2d664669..000000000000
--- a/arch/arm/mm/attrib_alloc.c
+++ /dev/null
@@ -1,126 +0,0 @@
-/*
- * arch/arm/mm/attrib_alloc.c
- *
- * Page allocator with custom cache attributes
- *
- * Copyright (c) 2010, NVIDIA Corporation.
- *
- * 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.
- *
- * This program is distributed in the hope that it will be useful, but WITHOUT
- * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
- * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
- * more details.
- *
- * You should have received a copy of the GNU General Public License along
- * with this program; if not, write to the Free Software Foundation, Inc.,
- * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
- */
-
-#include <linux/kernel.h>
-#include <linux/highmem.h>
-#include <linux/gfp.h>
-#include <linux/page-flags.h>
-#include <asm/tlbflush.h>
-#include <asm/cacheflush.h>
-#include <asm/pgtable.h>
-#include <asm/pgalloc.h>
-#include <asm/fixmap.h>
-#include <asm/outercache.h>
-#include <asm/attrib_alloc.h>
-#include "mm.h"
-
-static void update_kmap_pte(struct page *page, pgprot_t prot)
-{
-#ifdef CONFIG_HIGHMEM
-	unsigned long addr;
-	pte_t *pte;
-
-	addr = (unsigned long)kmap_high_get(page);
-	BUG_ON(!PageHighMem(page) || addr >= FIXADDR_START);
-	if (!addr)
-		return;
-
-	pte = &pkmap_page_table[PKMAP_NR(addr)];
-	set_pte_at(&init_mm, addr, pte, mk_pte(page, __pgprot(prot)));
-	flush_tlb_kernel_range(addr, addr + PAGE_SIZE);
-	kunmap_high(page);
-#endif
-}
-
-static void update_pte(struct page *page, pgprot_t prot)
-{
-#ifdef CONFIG_ARCH_LOWMEM_IN_PTES
-	unsigned long addr = (unsigned long)page_address(page);
-	pgd_t *pgd = pgd_offset_k(addr);
-	pmd_t *pmd = pmd_offset(pgd, addr);
-	pte_t *pte;
-
-	BUG_ON(pmd_none(*pmd));
-	pte = pte_offset_kernel(pmd, addr);
-	set_pte_at(&init_mm, addr, pte, mk_pte(page, __pgprot(prot)));
-	flush_tlb_kernel_range(addr, addr + PAGE_SIZE);
-#endif
-}
-
-void arm_attrib_free_pages_exact(struct page *page, size_t size)
-{
-	struct page *p, *e;
-
-	size = PAGE_ALIGN(size);
-	e = page + (size >> PAGE_SHIFT);
-
-	/* reset the page's mappings back to the standard kernel mappings
-	 * before returning it to the page allocator */
-	for (p = page; p < e; p++) {
-		if (PageHighMem(p))
-			update_kmap_pte(p, pgprot_kernel);
-		else
-			update_pte(p, pgprot_kernel);
-
-		__free_page(p);
-	}
-}
-
-struct page *arm_attrib_alloc_pages_exact_node(int nid, gfp_t gfp,
-					       size_t size, pgprot_t prot)
-{
-	struct page *page, *p, *e;
-	unsigned int order;
-	unsigned long base;
-
-	size = PAGE_ALIGN(size);
-	order = get_order(size);
-	page = alloc_pages_node(nid, gfp, order);
-
-	if (!page)
-		return NULL;
-
-	split_page(page, order);
-
-	e = page + (1 << order);
-	for (p = page + (size >> PAGE_SHIFT); p < e; p++)
-		__free_page(p);
-
-	e = page + (size >> PAGE_SHIFT);
-
-	for (p = page; p < e; p++) {
-		__flush_dcache_page(page_mapping(p), p);
-
-		/* even though a freshly-allocated highmem page shouldn't
-		 * be mapped, because the kmaps are flushed lazily, it
-		 * is possible that a mapping from an old kmap_high call
-		 * is still present, and its cache attributes need to
-		 * be updated to match the new expectations */
-		if (PageHighMem(p))
-			update_kmap_pte(p, prot);
-		else
-			update_pte(p, prot);
-	}
-	base = page_to_phys(page);
-	outer_flush_range(base, base + size);
-	return page;
-}