linux-kernel - [PATCH AUTOSEL for-4.4 37/39] MIPS: init: Ensure reserved memory regions are not added to bootmem

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Date:   Wed, 8 Nov 2017 20:50:42 +0000
From:   "Levin, Alexander (Sasha Levin)" <alexander.levin@....verizon.com>
To:     "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "stable@...r.kernel.org" <stable@...r.kernel.org>
CC:     Marcin Nowakowski <marcin.nowakowski@...tec.com>,
        "linux-mips@...ux-mips.org" <linux-mips@...ux-mips.org>,
        Ralf Baechle <ralf@...ux-mips.org>,
        "Levin, Alexander (Sasha Levin)" <alexander.levin@....verizon.com>
Subject: [PATCH AUTOSEL for-4.4 37/39] MIPS: init: Ensure reserved memory
 regions are not added to bootmem

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

[ Upstream commit e89ef66d7682f031f026eee6bba03c8c2248d2a9 ]

Memories managed through boot_mem_map are generally expected to define
non-crossing areas. However, if part of a larger memory block is marked
as reserved, it would still be added to bootmem allocator as an
available block and could end up being overwritten by the allocator.

Prevent this by explicitly marking the memory as reserved it if exists
in the range used by bootmem allocator.

Signed-off-by: Marcin Nowakowski <marcin.nowakowski@...tec.com>
Cc: linux-mips@...ux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/14608/
Signed-off-by: Ralf Baechle <ralf@...ux-mips.org>
Signed-off-by: Sasha Levin <alexander.levin@...izon.com>
---
 arch/mips/kernel/setup.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/mips/kernel/setup.c b/arch/mips/kernel/setup.c
index 1acaf0939cb5..4f9f1ae49213 100644
--- a/arch/mips/kernel/setup.c
+++ b/arch/mips/kernel/setup.c
@@ -506,6 +506,10 @@ static void __init bootmem_init(void)
 			continue;
 		default:
 			/* Not usable memory */
+			if (start > min_low_pfn && end < max_low_pfn)
+				reserve_bootmem(boot_mem_map.map[i].addr,
+						boot_mem_map.map[i].size,
+						BOOTMEM_DEFAULT);
 			continue;
 		}
 
-- 
2.11.0