[PATCH review for 4.4 07/47] MIPS: kexec: Do not reserve invalid crashkernel memory on boot

["Levin, Alexander (Sasha Levin)" <alexander.levin@verizon.com>]

From: Marcin Nowakowski <marcin.nowakowski@imgtec.com>

[ Upstream commit a8f108d70c74d83574c157648383eb2e4285a190 ]

Do not reserve memory for the crashkernel if the commandline argument
points to a wrong location. This can happen if the location is specified
wrong or if the same commandline is reused when starting the crashkernel
- in the latter case the reserved memory would point to the location
from which the crashkernel is executing.

Signed-off-by: Marcin Nowakowski <marcin.nowakowski@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/14612/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
---
 arch/mips/kernel/setup.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/arch/mips/kernel/setup.c b/arch/mips/kernel/setup.c
index 8acae316f26b..68f1118d10ad 100644
--- a/arch/mips/kernel/setup.c
+++ b/arch/mips/kernel/setup.c
@@ -596,6 +596,11 @@ static void __init mips_parse_crashkernel(void)
 	if (ret != 0 || crash_size <= 0)
 		return;
 
+	if (!memory_region_available(crash_base, crash_size)) {
+		pr_warn("Invalid memory region reserved for crash kernel\n");
+		return;
+	}
+
 	crashk_res.start = crash_base;
 	crashk_res.end	 = crash_base + crash_size - 1;
 }
-- 
2.11.0