x86, memblock: Use memblock_memory_size()/memblock_free_memory_size() to get correct dma_reserve

memblock_memory_size() will return memory size in memblock.memory.region.
memblock_free_memory_size() will return free memory size in memblock.memory.region.

So We can get exact reseved size in specified range.

Set the size right after initmem_init(), because later bootmem API will
get area above 16M. (except some fallback).

Later after we remove the bootmem, We could call that just before paging_init().

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>

1 files changed, 16 insertions, 0 deletions

diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c
index d5fd89462d79..0c2b7ef7a34d 100644
--- a/arch/x86/kernel/e820.c
+++ b/arch/x86/kernel/e820.c
@@ -1105,3 +1105,19 @@ void __init memblock_x86_fill(void)
 	memblock_analyze();
 	memblock_dump_all();
 }
+
+void __init memblock_find_dma_reserve(void)
+{
+#ifdef CONFIG_X86_64
+	u64 free_size_pfn;
+	u64 mem_size_pfn;
+	/*
+	 * need to find out used area below MAX_DMA_PFN
+	 * need to use memblock to get free size in [0, MAX_DMA_PFN]
+	 * at first, and assume boot_mem will not take below MAX_DMA_PFN
+	 */
+	mem_size_pfn = memblock_x86_memory_in_range(0, MAX_DMA_PFN << PAGE_SHIFT) >> PAGE_SHIFT;
+	free_size_pfn = memblock_x86_free_memory_in_range(0, MAX_DMA_PFN << PAGE_SHIFT) >> PAGE_SHIFT;
+	set_dma_reserve(mem_size_pfn - free_size_pfn);
+#endif
+}