[ARM] prevent the vmalloc cmdline argument from eating all memory

Commit 8d5796d2ec6b5a4e7a52861144e63af438d6f8f7 allows for the vmalloc
area to be resized from the kernel cmdline.  Make sure it cannot overlap
with RAM entirely.

Signed-off-by: Nicolas Pitre <nico@marvell.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c
index ab511d94d9178f0b49a89e649e9e1173fdcd247c..636cf8fc70ef4e7c24677d1e5e0ef04f4f1c4572 100644 (file)
--- a/arch/arm/mm/mmu.c
+++ b/arch/arm/mm/mmu.c
@@ -646,6 +646,13 @@ static void __init early_vmalloc(char **arg)
                        "vmalloc area too small, limiting to %luMB\n",
                        vmalloc_reserve >> 20);
        }
+
+       if (vmalloc_reserve > VMALLOC_END - (PAGE_OFFSET + SZ_32M)) {
+               vmalloc_reserve = VMALLOC_END - (PAGE_OFFSET + SZ_32M);
+               printk(KERN_WARNING
+                       "vmalloc area is too big, limiting to %luMB\n",
+                       vmalloc_reserve >> 20);
+       }
 }
 __early_param("vmalloc=", early_vmalloc);