[PATCH] x86/crash: Update the stale comment in reserve_crashkernel()

[Xunlei Pang]

CRASH_KERNEL_ADDR_MAX was missing for a long time, update it
with more detailed explanation.

Cc: Robert LeBlanc <***@leblancnet.us>
Cc: Baoquan He <***@redhat.com>
Signed-off-by: Xunlei Pang <***@redhat.com>
---
arch/x86/kernel/setup.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 9c337b0..79ee507 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -575,7 +575,10 @@ static void __init reserve_crashkernel(void)
/* 0 means: find the address automatically */
if (crash_base <= 0) {
/*
- * kexec want bzImage is below CRASH_KERNEL_ADDR_MAX
+ * Set CRASH_ADDR_LOW_MAX upper bound for crash range
+ * as old kexec-tools loads bzImage below that, unless
+ * "size,high" or "***@offset"(nonzero offset, see the
+ * else leg below) is specified.
*/
crash_base = memblock_find_in_range(CRASH_ALIGN,
high ? CRASH_ADDR_HIGH_MAX