[PATCH] riscv: mm: reserve the DTB before scanning reserved memory

[Marek Szyprowski]

early_init_fdt_scan_reserved_mem() allocates memory from memblock while
it scans /reserved-memory: the reserved_mem array, and the regions that
are placed dynamically by size. On RISC-V the DTB was only reserved
after that scan, so memblock could hand out the memory the DTB occupies
while the DTB was still being parsed.

Reserve the DTB before the scan, so that memblock never allocates from
it.

Fixes: ef69d2559fe9 ("riscv: Move early dtb mapping into the fixmap region")
Closes: https://lore.kernel.org/all/b71ac175-fba5-4f61-bbdb-0b98dec9ccee@samsung.com/
Signed-off-by: Marek Szyprowski <m.szyprowski at samsung.com>
---
 arch/riscv/mm/init.c | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
index e822fce0af4b..bbc2d8cb4627 100644
--- a/arch/riscv/mm/init.c
+++ b/arch/riscv/mm/init.c
@@ -294,13 +294,6 @@ static void __init setup_bootmem(void)
 
 	reserve_initrd_mem();
 
-	/*
-	 * No allocation should be done before reserving the memory as defined
-	 * in the device tree, otherwise the allocation could end up in a
-	 * reserved region.
-	 */
-	early_init_fdt_scan_reserved_mem();
-
 	/*
 	 * If DTB is built in, no need to reserve its memblock.
 	 * Otherwise, do reserve it but avoid using
@@ -309,6 +302,13 @@ static void __init setup_bootmem(void)
 	 */
 	if (!IS_ENABLED(CONFIG_BUILTIN_DTB))
 		memblock_reserve(dtb_early_pa, fdt_totalsize(dtb_early_va));
+
+	/*
+	 * No allocation should be done before reserving the memory as defined
+	 * in the device tree, otherwise the allocation could end up in a
+	 * reserved region.
+	 */
+	early_init_fdt_scan_reserved_mem();
 }
 
 #ifdef CONFIG_RELOCATABLE
-- 
2.43.0