From 40f18dbbb42c56019b889b5b1fdce3da89e354da Mon Sep 17 00:00:00 2001
From: Stephen Boyd <sboyd@kernel.org>
Date: Fri, 16 Feb 2024 17:05:53 -0800
Subject: [PATCH] x86/of: Unconditionally call unflatten_and_copy_device_tree()
Call this function unconditionally so that we can populate an empty DTB
on platforms that don't boot with a firmware provided or builtin DTB.
There's no harm in calling unflatten_device_tree() unconditionally here.
If there isn't a non-NULL 'initial_boot_params' pointer then
unflatten_device_tree() returns early.
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Frank Rowand <frowand.list@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: x86@kernel.org
Cc: H. Peter Anvin <hpa@zytor.com>
Tested-by: Saurabh Sengar <ssengar@linux.microsoft.com>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
Link: https://lore.kernel.org/r/20240217010557.2381548-5-sboyd@kernel.org
Signed-off-by: Rob Herring <robh@kernel.org>
---
arch/x86/kernel/devicetree.c | 26 ++++++++++++++------------
1 file changed, 14 insertions(+), 12 deletions(-)
diff --git a/arch/x86/kernel/devicetree.c b/arch/x86/kernel/devicetree.c
index afd09924094ec..650752d112a64 100644
--- a/arch/x86/kernel/devicetree.c
+++ b/arch/x86/kernel/devicetree.c
@@ -283,22 +283,24 @@ void __init x86_flattree_get_config(void)
u32 size, map_len;
void *dt;
- if (!initial_dtb)
- return;
-
- map_len = max(PAGE_SIZE - (initial_dtb & ~PAGE_MASK), (u64)128);
+ if (initial_dtb) {
+ map_len = max(PAGE_SIZE - (initial_dtb & ~PAGE_MASK), (u64)128);
+
+ dt = early_memremap(initial_dtb, map_len);
+ size = fdt_totalsize(dt);
+ if (map_len < size) {
+ early_memunmap(dt, map_len);
+ dt = early_memremap(initial_dtb, size);
+ map_len = size;
+ }
- dt = early_memremap(initial_dtb, map_len);
- size = fdt_totalsize(dt);
- if (map_len < size) {
- early_memunmap(dt, map_len);
- dt = early_memremap(initial_dtb, size);
- map_len = size;
+ early_init_dt_verify(dt);
}
- early_init_dt_verify(dt);
unflatten_and_copy_device_tree();
- early_memunmap(dt, map_len);
+
+ if (initial_dtb)
+ early_memunmap(dt, map_len);
}
#endif
--
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