x86_64: allocate gart aperture from 512M

[pandora-kernel.git] / arch / x86 / kernel / aperture_64.c

diff --git a/arch/x86/kernel/aperture_64.c b/arch/x86/kernel/aperture_64.c
index 8c325b7..c63f8d9 100644 (file)
--- a/arch/x86/kernel/aperture_64.c
+++ b/arch/x86/kernel/aperture_64.c
@@ -55,8 +55,9 @@ static u32 __init allocate_aperture(void)
        u32 aper_size;
        void *p;
 
-       if (fallback_aper_order > 7)
-               fallback_aper_order = 7;
+       /* aper_size should <= 1G */
+       if (fallback_aper_order > 5)
+               fallback_aper_order = 5;
        aper_size = (32 * 1024 * 1024) << fallback_aper_order;
 
        /*
@@ -65,7 +66,20 @@ static u32 __init allocate_aperture(void)
         * memory. Unfortunately we cannot move it up because that would
         * make the IOMMU useless.
         */
-       p = __alloc_bootmem_nopanic(aper_size, aper_size, 0);
+       /*
+        * using 512M as goal, in case kexec will load kernel_big
+        * that will do the on position decompress, and  could overlap with
+        * that positon with gart that is used.
+        * sequende:
+        * kernel_small
+        * ==> kexec (with kdump trigger path or previous doesn't shutdown gart)
+        * ==> kernel_small(gart area become e820_reserved)
+        * ==> kexec (with kdump trigger path or previous doesn't shutdown gart)
+        * ==> kerne_big (uncompressed size will be big than 64M or 128M)
+        * so don't use 512M below as gart iommu, leave the space for kernel
+        * code for safe
+        */
+       p = __alloc_bootmem_nopanic(aper_size, aper_size, 512ULL<<20);
        if (!p || __pa(p)+aper_size > 0xffffffff) {
                printk(KERN_ERR
                        "Cannot allocate aperture memory hole (%p,%uK)\n",