linux-kernel - [PATCH 3/3] efi: enforce usable memory range after reserving regions

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Date:   Mon, 10 Jan 2022 21:08:09 +0000
From:   Frank van der Linden <fllinden@...zon.com>
To:     <linux-arm-kernel@...ts.infradead.org>, <rppt@...nel.org>,
        <robh+dt@...nel.org>, <frowand.list@...il.com>, <ardb@...nel.org>,
        <linux-mm@...ck.org>, <devicetree@...r.kernel.org>,
        <linux-efi@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <kexec@...ts.infradead.org>, <catalin.marinas@....com>,
        <will@...nel.org>
CC:     <geert+renesas@...der.be>,
        Frank van der Linden <fllinden@...zon.com>
Subject: [PATCH 3/3] efi: enforce usable memory range after reserving regions

The usable memory range may be restricted through parameters that
did not come from EFI, like the FDT "linux,usable-memory-range"
property.

Enforce this range after the EFI memory map regions have been
processed.

Signed-off-by: Frank van der Linden <fllinden@...zon.com>
---
 drivers/firmware/efi/efi-init.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/firmware/efi/efi-init.c b/drivers/firmware/efi/efi-init.c
index b19ce1a83f91..280e9178c7df 100644
--- a/drivers/firmware/efi/efi-init.c
+++ b/drivers/firmware/efi/efi-init.c
@@ -204,6 +204,13 @@ static __init void reserve_regions(void)
 				memblock_reserve(paddr, size);
 		}
 	}
+
+	/*
+	 * Done, filter !nomap memory we just added so that the
+	 * usable range is enforced. This is normally only set
+	 * for crash kernels on some architectures.
+	 */
+	memblock_enforce_usable_range();
 }
 
 void __init efi_init(void)
-- 
2.32.0