[PATCH] x86_64: Use the e820 hole to map the IOMMU/AGP aperture (ece90303) · Commits · 戴 / test

arch/x86_64/kernel/aperture.c

+30 −11

Original line number	Diff line number	Diff line
		@@ -33,11 +33,13 @@ int fallback_aper_force __initdata = 0;

		int fix_aperture __initdata = 1;

		/* This code runs before the PCI subsystem is initialized, so just
		access the northbridge directly. */

		#define NB_ID_3 (PCI_VENDOR_ID_AMD \| (0x1103<<16))

		static struct resource aper_res = {
		.name = "Aperture",
		.flags = IORESOURCE_MEM,
		};

		static u32 __init allocate_aperture(void)
		{
		#ifdef CONFIG_DISCONTIGMEM
		@@ -53,11 +55,24 @@ static u32 __init allocate_aperture(void)
		aper_size = (32 * 1024 * 1024) << fallback_aper_order;

		/*
		* Aperture has to be naturally aligned. This means an 2GB aperture won't
		* have much chances to find a place in the lower 4GB of memory.
		* Unfortunately we cannot move it up because that would make the
		* IOMMU useless.
		* Aperture has to be naturally aligned. This means an 2GB
		* aperture won't have much chances to find a place in the
		* lower 4GB of memory. Unfortunately we cannot move it up
		* because that would make the IOMMU useless.
		*/

		/* First try to find some free unused space */
		if (!allocate_resource(&iomem_resource, &aper_res,
		aper_size,
		0, 0xffffffff,
		aper_size,
		NULL, NULL)) {
		printk(KERN_INFO "Putting aperture at %lx-%lx\n",
		aper_res.start, aper_res.end);
		return aper_res.start;
		}

		/* No free space found. Go on to waste some memory... */
		p = __alloc_bootmem_node(nd0, aper_size, aper_size, 0);
		if (!p \|\| __pa(p)+aper_size > 0xffffffff) {
		printk("Cannot allocate aperture memory hole (%p,%uK)\n",
		@@ -66,7 +81,7 @@ static u32 __init allocate_aperture(void)
		free_bootmem_node(nd0, (unsigned long)p, aper_size);
		return 0;
		}
		printk("Mapping aperture over %d KB of RAM @ %lx\n",
		printk("Mapping aperture over %d KB of precious RAM @ %lx\n",
		aper_size >> 10, __pa(p));
		return (u32)__pa(p);
		}
		@@ -87,10 +102,16 @@ static int __init aperture_valid(char *name, u64 aper_base, u32 aper_size)
		printk("Aperture from %s pointing to e820 RAM. Ignoring.\n",name);
		return 0;
		}
		/* Don't check the resource here because the aperture is usually
		in an e820 reserved area, and we allocated these earlier. */
		return 1;
		}

		/* Find a PCI capability */
		/*
		* Find a PCI capability.
		* This code runs before the PCI subsystem is initialized, so just
		* access the northbridge directly.
		*/
		static __u32 __init find_cap(int num, int slot, int func, int cap)
		{
		u8 pos;
		@@ -255,8 +276,6 @@ void __init iommu_hole_init(void)
		fallback_aper_force) {
		printk("Your BIOS doesn't leave a aperture memory hole\n");
		printk("Please enable the IOMMU option in the BIOS setup\n");
		printk("This costs you %d MB of RAM\n",
		32 << fallback_aper_order);

		aper_order = fallback_aper_order;
		aper_alloc = allocate_aperture();

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