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authorRusty Russell <rusty@rustcorp.com.au>2008-03-11 10:35:56 -0400
committerRusty Russell <rusty@rustcorp.com.au>2008-03-10 18:35:56 -0400
commitf14ae652baa3d72ae378f0c06b89cc2c4ef15ff8 (patch)
tree65dfe2b310103bd6f2c981de2e1d0faecd05805c /drivers
parentf73d1e6ca6985b43a1871467463cba632fbc624d (diff)
lguest: fix __get_vm_area usage.
Robert Bragg's 5dc331852848a38ca00a2817e5b98a1d0561b116 tightened (ie. fixed) the checking in __get_vm_area, and it broke lguest. lguest should pass the exact "end" it wants, not some random constant (it was possible previously that it would actually get an address different from SWITCHER_ADDR). Also, Fabio Checconi pointed out that we should make sure we're not hitting the fixmap area. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Cc: Robert Bragg <robert@sixbynine.org>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/lguest/core.c15
1 files changed, 13 insertions, 2 deletions
diff --git a/drivers/lguest/core.c b/drivers/lguest/core.c
index 7743d73768df..c632c08cbbdc 100644
--- a/drivers/lguest/core.c
+++ b/drivers/lguest/core.c
@@ -69,11 +69,22 @@ static __init int map_switcher(void)
69 switcher_page[i] = virt_to_page(addr); 69 switcher_page[i] = virt_to_page(addr);
70 } 70 }
71 71
72 /* First we check that the Switcher won't overlap the fixmap area at
73 * the top of memory. It's currently nowhere near, but it could have
74 * very strange effects if it ever happened. */
75 if (SWITCHER_ADDR + (TOTAL_SWITCHER_PAGES+1)*PAGE_SIZE > FIXADDR_START){
76 err = -ENOMEM;
77 printk("lguest: mapping switcher would thwack fixmap\n");
78 goto free_pages;
79 }
80
72 /* Now we reserve the "virtual memory area" we want: 0xFFC00000 81 /* Now we reserve the "virtual memory area" we want: 0xFFC00000
73 * (SWITCHER_ADDR). We might not get it in theory, but in practice 82 * (SWITCHER_ADDR). We might not get it in theory, but in practice
74 * it's worked so far. */ 83 * it's worked so far. The end address needs +1 because __get_vm_area
84 * allocates an extra guard page, so we need space for that. */
75 switcher_vma = __get_vm_area(TOTAL_SWITCHER_PAGES * PAGE_SIZE, 85 switcher_vma = __get_vm_area(TOTAL_SWITCHER_PAGES * PAGE_SIZE,
76 VM_ALLOC, SWITCHER_ADDR, VMALLOC_END); 86 VM_ALLOC, SWITCHER_ADDR, SWITCHER_ADDR
87 + (TOTAL_SWITCHER_PAGES+1) * PAGE_SIZE);
77 if (!switcher_vma) { 88 if (!switcher_vma) {
78 err = -ENOMEM; 89 err = -ENOMEM;
79 printk("lguest: could not map switcher pages high\n"); 90 printk("lguest: could not map switcher pages high\n");