[PATCH for 4.9 11/59] MIPS: fix mem=X@Y commandline processing

[Levin, Alexander (Sasha Levin)]

From: Marcin Nowakowski <marcin.nowakowski@xxxxxxxxxx>

[ Upstream commit 73fbc1eba7ffa3bf0ad12486232a8a1edb4e4411 ]

When a memory offset is specified through the commandline, add the
memory in range PHYS_OFFSET:Y as reserved memory area.
Otherwise the bootmem allocator is initialised with low page equal to
min_low_pfn = PHYS_OFFSET, and in free_all_bootmem will process pages
starting from min_low_pfn instead of PFN(Y).

Signed-off-by: Marcin Nowakowski <marcin.nowakowski@xxxxxxxxxx>
Cc: linux-mips@xxxxxxxxxxxxxx
Patchwork: https://patchwork.linux-mips.org/patch/14613/
Signed-off-by: Ralf Baechle <ralf@xxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxx>
---
 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 f66e5ce505b2..38697f25d168 100644
--- a/arch/mips/kernel/setup.c
+++ b/arch/mips/kernel/setup.c
@@ -589,6 +589,10 @@ static int __init early_parse_mem(char *p)
 		start = memparse(p + 1, &p);
 
 	add_memory_region(start, size, BOOT_MEM_RAM);
+
+	if (start && start > PHYS_OFFSET)
+		add_memory_region(PHYS_OFFSET, start - PHYS_OFFSET,
+				BOOT_MEM_RESERVED);
 	return 0;
 }
 early_param("mem", early_parse_mem);
-- 
2.11.0