Merge tag 'xtensa-20180225' of git://github.com/jcmvbkbc/linux-xtensa

Pull Xtensa fixes from Max Filippov:
 "Two fixes for reserved memory/DMA buffers allocation in high memory on
  xtensa architecture

   - fix memory accounting when reserved memory is in high memory region

   - fix DMA allocation from high memory"

* tag 'xtensa-20180225' of git://github.com/jcmvbkbc/linux-xtensa:
  xtensa: support DMA buffers in high memory
  xtensa: fix high memory/reserved memory collision

arch/xtensa/kernel/pci-dma.c

@@ -16,6 +16,7 @@
  */
 
 #include <linux/dma-contiguous.h>
+#include <linux/dma-direct.h>
 #include <linux/gfp.h>
 #include <linux/highmem.h>
 #include <linux/mm.h>
@@ -123,7 +124,7 @@ static void *xtensa_dma_alloc(struct device *dev, size_t size,
 			      unsigned long attrs)
 {
 	unsigned long ret;
-	unsigned long uncached = 0;
+	unsigned long uncached;
 	unsigned long count = PAGE_ALIGN(size) >> PAGE_SHIFT;
 	struct page *page = NULL;
 
@@ -144,15 +145,27 @@ static void *xtensa_dma_alloc(struct device *dev, size_t size,
 	if (!page)
 		return NULL;
 
-	ret = (unsigned long)page_address(page);
+	*handle = phys_to_dma(dev, page_to_phys(page));
 
-	/* We currently don't support coherent memory outside KSEG */
+#ifdef CONFIG_MMU
+	if (PageHighMem(page)) {
+		void *p;
 
+		p = dma_common_contiguous_remap(page, size, VM_MAP,
+						pgprot_noncached(PAGE_KERNEL),
+						__builtin_return_address(0));
+		if (!p) {
+			if (!dma_release_from_contiguous(dev, page, count))
+				__free_pages(page, get_order(size));
+		}
+		return p;
+	}
+#endif
+	ret = (unsigned long)page_address(page);
 	BUG_ON(ret < XCHAL_KSEG_CACHED_VADDR ||
 	       ret > XCHAL_KSEG_CACHED_VADDR + XCHAL_KSEG_SIZE - 1);
 
 	uncached = ret + XCHAL_KSEG_BYPASS_VADDR - XCHAL_KSEG_CACHED_VADDR;
-	*handle = virt_to_bus((void *)ret);
 	__invalidate_dcache_range(ret, size);
 
 	return (void *)uncached;
@@ -161,13 +174,20 @@ static void *xtensa_dma_alloc(struct device *dev, size_t size,
 static void xtensa_dma_free(struct device *dev, size_t size, void *vaddr,
 			    dma_addr_t dma_handle, unsigned long attrs)
 {
-	unsigned long addr = (unsigned long)vaddr +
-		XCHAL_KSEG_CACHED_VADDR - XCHAL_KSEG_BYPASS_VADDR;
-	struct page *page = virt_to_page(addr);
 	unsigned long count = PAGE_ALIGN(size) >> PAGE_SHIFT;
-
-	BUG_ON(addr < XCHAL_KSEG_CACHED_VADDR ||
-	       addr > XCHAL_KSEG_CACHED_VADDR + XCHAL_KSEG_SIZE - 1);
+	unsigned long addr = (unsigned long)vaddr;
+	struct page *page;
+
+	if (addr >= XCHAL_KSEG_BYPASS_VADDR &&
+	    addr - XCHAL_KSEG_BYPASS_VADDR < XCHAL_KSEG_SIZE) {
+		addr += XCHAL_KSEG_CACHED_VADDR - XCHAL_KSEG_BYPASS_VADDR;
+		page = virt_to_page(addr);
+	} else {
+#ifdef CONFIG_MMU
+		dma_common_free_remap(vaddr, size, VM_MAP);
+#endif
+		page = pfn_to_page(PHYS_PFN(dma_to_phys(dev, dma_handle)));
+	}
 
 	if (!dma_release_from_contiguous(dev, page, count))
 		__free_pages(page, get_order(size));

arch/xtensa/mm/init.c

@@ -79,19 +79,75 @@ void __init zones_init(void)
 	free_area_init_node(0, zones_size, ARCH_PFN_OFFSET, NULL);
 }
 
+#ifdef CONFIG_HIGHMEM
+static void __init free_area_high(unsigned long pfn, unsigned long end)
+{
+	for (; pfn < end; pfn++)
+		free_highmem_page(pfn_to_page(pfn));
+}
+
+static void __init free_highpages(void)
+{
+	unsigned long max_low = max_low_pfn;
+	struct memblock_region *mem, *res;
+
+	reset_all_zones_managed_pages();
+	/* set highmem page free */
+	for_each_memblock(memory, mem) {
+		unsigned long start = memblock_region_memory_base_pfn(mem);
+		unsigned long end = memblock_region_memory_end_pfn(mem);
+
+		/* Ignore complete lowmem entries */
+		if (end <= max_low)
+			continue;
+
+		if (memblock_is_nomap(mem))
+			continue;
+
+		/* Truncate partial highmem entries */
+		if (start < max_low)
+			start = max_low;
+
+		/* Find and exclude any reserved regions */
+		for_each_memblock(reserved, res) {
+			unsigned long res_start, res_end;
+
+			res_start = memblock_region_reserved_base_pfn(res);
+			res_end = memblock_region_reserved_end_pfn(res);
+
+			if (res_end < start)
+				continue;
+			if (res_start < start)
+				res_start = start;
+			if (res_start > end)
+				res_start = end;
+			if (res_end > end)
+				res_end = end;
+			if (res_start != start)
+				free_area_high(start, res_start);
+			start = res_end;
+			if (start == end)
+				break;
+		}
+
+		/* And now free anything which remains */
+		if (start < end)
+			free_area_high(start, end);
+	}
+}
+#else
+static void __init free_highpages(void)
+{
+}
+#endif
+
 /*
  * Initialize memory pages.
  */
 
 void __init mem_init(void)
 {
-#ifdef CONFIG_HIGHMEM
-	unsigned long tmp;
-
-	reset_all_zones_managed_pages();
-	for (tmp = max_low_pfn; tmp < max_pfn; tmp++)
-		free_highmem_page(pfn_to_page(tmp));
-#endif
+	free_highpages();
 
 	max_mapnr = max_pfn - ARCH_PFN_OFFSET;
 	high_memory = (void *)__va(max_low_pfn << PAGE_SHIFT);