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From:   Hsin-Yi Wang <hsinyi@chromium.org>
To:     linux-arm-kernel@lists.infradead.org
Cc:     Rob Herring <robh+dt@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>,
        Frank Rowand <frowand.list@gmail.com>,
        Hsin-Yi Wang <hsinyi@chromium.org>, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org, Stephen Boyd <swboyd@chromium.org>,
        Kees Cook <keescook@chromium.org>,
        Rasmus Villemoes <linux@rasmusvillemoes.dk>,
        boot-architecture@lists.linaro.org,
        Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will.deacon@arm.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Mike Rapoport <rppt@linux.ibm.com>,
        Michal Hocko <mhocko@suse.com>,
        Ard Biesheuvel <ard.biesheuvel@linaro.org>,
        Miles Chen <miles.chen@mediatek.com>,
        James Morse <james.morse@arm.com>,
        Andrew Murray <andrew.murray@arm.com>
Subject: [PATCH v2 2/2] amr64: map FDT as RW for early_init_dt_scan()
Date:   Mon, 13 May 2019 08:38:19 +0800
Message-Id: <20190513003819.356-2-hsinyi@chromium.org>
In-Reply-To: <20190513003819.356-1-hsinyi@chromium.org>
References: <20190513003819.356-1-hsinyi@chromium.org>
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Currently in arm64, FDT is mapped to RO before it's passed to
early_init_dt_scan(). However, there might be some code that needs
to modify FDT during init. Map FDT to RW until unflatten DT.

Signed-off-by: Hsin-Yi Wang <hsinyi@chromium.org>
---
 arch/arm64/kernel/setup.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
index 413d566405d1..08b22c1e72a9 100644
--- a/arch/arm64/kernel/setup.c
+++ b/arch/arm64/kernel/setup.c
@@ -179,9 +179,13 @@ static void __init smp_build_mpidr_hash(void)
 		pr_warn("Large number of MPIDR hash buckets detected\n");
 }
 
+extern void *__init __fixmap_remap_fdt(phys_addr_t dt_phys, int *size,
+				       pgprot_t prot);
+
 static void __init setup_machine_fdt(phys_addr_t dt_phys)
 {
-	void *dt_virt = fixmap_remap_fdt(dt_phys);
+	int size;
+	void *dt_virt = __fixmap_remap_fdt(dt_phys, &size, PAGE_KERNEL);
 	const char *name;
 
 	if (!dt_virt || !early_init_dt_scan(dt_virt)) {
@@ -320,6 +324,9 @@ void __init setup_arch(char **cmdline_p)
 	/* Parse the ACPI tables for possible boot-time configuration */
 	acpi_boot_table_init();
 
+	/* remap fdt to RO */
+	fixmap_remap_fdt(__fdt_pointer);
+
 	if (acpi_disabled)
 		unflatten_device_tree();
 
-- 
2.20.1