x86, e820, pci: reserve extra free space near end of RAM (45fbe3ee) · Commits · 戴 / test

The point is to take all RAM resources we have, and _after_ we've added all the resources we've seen in the E820 tree, we then _also_ try to add fake reserved entries for any "round up to X" at the end of the RAM resources. [ Impact: improve PCI mem-resource allocation robustness, protect "stolen RAM" ] Reported-by:

Yannick Roehlly <yannick.roehlly@free.fr> Acked-by:

Jesse Barnes <jesse.barnes@intel.com> Signed-off-by:

Yinghai Lu <yinghai@kernel.org> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: yannick.roehlly@free.fr LKML-Reference: <4A01A784.2050407@kernel.org> Signed-off-by:

Ingo Molnar <mingo@elte.hu>

arch/x86/kernel/e820.c

+35 −0

Original line number	Diff line number	Diff line
		@@ -1371,6 +1371,23 @@ void __init e820_reserve_resources(void)
		}
		}

		/* How much should we pad RAM ending depending on where it is? */
		static unsigned long ram_alignment(resource_size_t pos)
		{
		unsigned long mb = pos >> 20;

		/* To 64kB in the first megabyte */
		if (!mb)
		return 64*1024;

		/* To 1MB in the first 16MB */
		if (mb < 16)
		return 1024*1024;

		/* To 32MB for anything above that */
		return 3210241024;
		}

		void __init e820_reserve_resources_late(void)
		{
		int i;
		@@ -1382,6 +1399,24 @@ void __init e820_reserve_resources_late(void)
		insert_resource_expand_to_fit(&iomem_resource, res);
		res++;
		}

		/*
		* Try to bump up RAM regions to reasonable boundaries to
		* avoid stolen RAM:
		*/
		for (i = 0; i < e820.nr_map; i++) {
		struct e820entry *entry = &e820_saved.map[i];
		resource_size_t start, end;

		if (entry->type != E820_RAM)
		continue;
		start = entry->addr + entry->size;
		end = round_up(start, ram_alignment(start));
		if (start == end)
		continue;
		reserve_region_with_split(&iomem_resource, start,
		end - 1, "RAM buffer");
		}
		}

		char *__init default_machine_specific_memory_setup(void)

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