powerpc/kexec: Check crash_base for relocatable kernel
Enforce that the crash kernel region never overlaps the current kernel,
as it will be written directly on kexec load.
Also, default to the previous KDUMP_KERNELBASE if the start is 0.
Other architectures (x86, ia64) state that specifying the start address
0 (or omitting it) will result in the kernel allocating it. Before the
relocatable patch in 2.6.28, powerpc would adjust any other start value
to the hardcoded KDUMP_KERNELBASE of 32M.
Signed-off-by: Milton Miller <miltonm@bga.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
diff --git a/arch/powerpc/kernel/machine_kexec.c b/arch/powerpc/kernel/machine_kexec.c
index b3abebb..d59e2b1 100644
--- a/arch/powerpc/kernel/machine_kexec.c
+++ b/arch/powerpc/kernel/machine_kexec.c
@@ -93,10 +93,35 @@
KDUMP_KERNELBASE);
crashk_res.start = KDUMP_KERNELBASE;
+#else
+ if (!crashk_res.start) {
+ /*
+ * unspecified address, choose a region of specified size
+ * can overlap with initrd (ignoring corruption when retained)
+ * ppc64 requires kernel and some stacks to be in first segemnt
+ */
+ crashk_res.start = KDUMP_KERNELBASE;
+ }
+
+ crash_base = PAGE_ALIGN(crashk_res.start);
+ if (crash_base != crashk_res.start) {
+ printk("Crash kernel base must be aligned to 0x%lx\n",
+ PAGE_SIZE);
+ crashk_res.start = crash_base;
+ }
+
#endif
crash_size = PAGE_ALIGN(crash_size);
crashk_res.end = crashk_res.start + crash_size - 1;
+ /* The crash region must not overlap the current kernel */
+ if (overlaps_crashkernel(__pa(_stext), _end - _stext)) {
+ printk(KERN_WARNING
+ "Crash kernel can not overlap current kernel\n");
+ crashk_res.start = crashk_res.end = 0;
+ return;
+ }
+
/* Crash kernel trumps memory limit */
if (memory_limit && memory_limit <= crashk_res.end) {
memory_limit = crashk_res.end + 1;
