From 6ac5a11dc674bc5016ea716e8082fff61f524dc1 Mon Sep 17 00:00:00 2001 From: Max Filippov Date: Tue, 13 Feb 2018 15:31:05 -0800 Subject: [PATCH 1/2] xtensa: fix high memory/reserved memory collision Xtensa memory initialization code frees high memory pages without checking whether they are in the reserved memory regions or not. That results in invalid value of totalram_pages and duplicate page usage by CMA and highmem. It produces a bunch of BUGs at startup looking like this: BUG: Bad page state in process swapper pfn:70800 page:be60c000 count:0 mapcount:-127 mapping: (null) index:0x1 flags: 0x80000000() raw: 80000000 00000000 00000001 ffffff80 00000000 be60c014 be60c014 0000000a page dumped because: nonzero mapcount Modules linked in: CPU: 0 PID: 1 Comm: swapper Tainted: G B 4.16.0-rc1-00015-g7928b2cbe55b-dirty #23 Stack: bd839d33 00000000 00000018 ba97b64c a106578c bd839d70 be60c000 00000000 a1378054 bd86a000 00000003 ba97b64c a1066166 bd839da0 be60c000 ffe00000 a1066b58 bd839dc0 be504000 00000000 000002f4 bd838000 00000000 0000001e Call Trace: [] bad_page+0xac/0xd0 [] free_pages_check_bad+0x34/0x4c [] __free_pages_ok+0xae/0x14c [] __free_pages+0x30/0x64 [] init_cma_reserved_pageblock+0x35/0x44 [] cma_init_reserved_areas+0xf4/0x148 [] do_one_initcall+0x80/0xf8 [] kernel_init_freeable+0xda/0x13c [] kernel_init+0x9/0xd0 [] ret_from_kernel_thread+0xc/0x18 Only free high memory pages that are not reserved. Cc: stable@vger.kernel.org Signed-off-by: Max Filippov --- arch/xtensa/mm/init.c | 70 ++++++++++++++++++++++++++++++++++++++----- 1 file changed, 63 insertions(+), 7 deletions(-) diff --git a/arch/xtensa/mm/init.c b/arch/xtensa/mm/init.c index d776ec0d7b22..34aead7dcb48 100644 --- a/arch/xtensa/mm/init.c +++ b/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); From 6137e4166004e2ec383ac05d5ca15831f4668806 Mon Sep 17 00:00:00 2001 From: Max Filippov Date: Wed, 14 Feb 2018 16:12:54 -0800 Subject: [PATCH 2/2] xtensa: support DMA buffers in high memory If a DMA buffer is allocated in high memory and kernel mapping is required use dma_common_contiguous_remap to map buffer to the vmalloc region and dma_common_free_remap to unmap it. Signed-off-by: Max Filippov --- arch/xtensa/kernel/pci-dma.c | 40 +++++++++++++++++++++++++++--------- 1 file changed, 30 insertions(+), 10 deletions(-) diff --git a/arch/xtensa/kernel/pci-dma.c b/arch/xtensa/kernel/pci-dma.c index 623720a11143..732631ce250f 100644 --- a/arch/xtensa/kernel/pci-dma.c +++ b/arch/xtensa/kernel/pci-dma.c @@ -16,6 +16,7 @@ */ #include +#include #include #include #include @@ -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; + *handle = phys_to_dma(dev, page_to_phys(page)); + +#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); - - /* We currently don't support coherent memory outside KSEG */ - 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; + unsigned long addr = (unsigned long)vaddr; + struct page *page; - BUG_ON(addr < XCHAL_KSEG_CACHED_VADDR || - addr > XCHAL_KSEG_CACHED_VADDR + XCHAL_KSEG_SIZE - 1); + 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));