[PATCH v4 1/2] x86/of: add early setup of DT reserved-memory nodes

[Grzegorz Jaszczyk <jaszczyk@chromium.org>]

The x86 allows booting with ACPI and DT simultaneously, and while basic
DT support is present, the processing of DT 'reserved-memory' is
currently missing.

Some drivers (such as open-dice driver) rely on the standard device-tree
bindings (Documentation/devicetree/bindings/reserved-memory/) to
communicate securely reserved memory region.

To support this add early_init_fdt_scan_reserved_mem as part of early
flattened device tree parsing.

Additionally this patch changes the sequence and calls
x86_flattree_get_config earlier in `setup_arch()`, just after e820
memblock setup, so the DT reserved-memory can be properly reflected in
the memblock before that reserved-memory is used for allocation.

Signed-off-by: Grzegorz Jaszczyk <jaszczyk@google.com>
---
 arch/x86/kernel/devicetree.c | 1 +
 arch/x86/kernel/setup.c      | 4 ++--
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/devicetree.c b/arch/x86/kernel/devicetree.c
index dd8748c45529..f7db0e8f9c3e 100644
--- a/arch/x86/kernel/devicetree.c
+++ b/arch/x86/kernel/devicetree.c
@@ -307,6 +307,7 @@ void __init x86_flattree_get_config(void)
 		}
 
 		early_init_dt_verify(dt, __pa(dt));
+		early_init_fdt_scan_reserved_mem();
 	}
 
 	unflatten_and_copy_device_tree();
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index eebcc9db1a1b..cf6c93f8be1a 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -1076,6 +1076,8 @@ void __init setup_arch(char **cmdline_p)
 
 	e820__memblock_setup();
 
+	x86_flattree_get_config();
+
 	/*
 	 * Needs to run after memblock setup because it needs the physical
 	 * memory size.
@@ -1186,8 +1188,6 @@ void __init setup_arch(char **cmdline_p)
 	early_acpi_boot_init();
 	x86_init.mpparse.early_parse_smp_cfg();
 
-	x86_flattree_get_config();
-
 	initmem_init();
 	dma_contiguous_reserve(max_pfn_mapped << PAGE_SHIFT);
 
-- 
2.53.0.851.ga537e3e6e9-goog