1 files changed, 28 insertions, 0 deletions

diff --git a/arch/x86_64/kernel/machine_kexec.c b/arch/x86_64/kernel/machine_kexec.c
index 106076b370fc..2e94c072d84a 100644
--- a/arch/x86_64/kernel/machine_kexec.c
+++ b/arch/x86_64/kernel/machine_kexec.c
@@ -226,3 +226,31 @@ NORET_TYPE void machine_kexec(struct kimage *image)
         rnk = (relocate_new_kernel_t) control_code_buffer;
         (*rnk)(page_list, control_code_buffer, image->start, start_pgtable);
 }
+
+/* crashkernel=size@addr specifies the location to reserve for
+ * a crash kernel.  By reserving this memory we guarantee
+ * that linux never set's it up as a DMA target.
+ * Useful for holding code to do something appropriate
+ * after a kernel panic.
+ */
+static int __init setup_crashkernel(char *arg)
+{
+        unsigned long size, base;
+        char *p;
+        if (!arg)
+                return -EINVAL;
+        size = memparse(arg, &p);
+        if (arg == p)
+                return -EINVAL;
+        if (*p == '@') {
+                base = memparse(p+1, &p);
+                /* FIXME: Do I want a sanity check to validate the
+                 * memory range?  Yes you do, but it's too early for
+                 * e820 -AK */
+                crashk_res.start = base;
+                crashk_res.end   = base + size - 1;
+        }
+        return 0;
+}
+early_param("crashkernel", setup_crashkernel);
+