linux-kernel - [PATCH -fixes 2/2] riscv: Do not set initial_boot

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Date:   Thu, 23 Mar 2023 17:33:47 +0100
From:   Alexandre Ghiti <alexghiti@...osinc.com>
To:     Jonathan Corbet <corbet@....net>,
        Paul Walmsley <paul.walmsley@...ive.com>,
        Palmer Dabbelt <palmer@...belt.com>,
        Albert Ou <aou@...s.berkeley.edu>,
        Conor Dooley <conor.dooley@...rochip.com>,
        linux-doc@...r.kernel.org, linux-riscv@...ts.infradead.org,
        linux-kernel@...r.kernel.org
Cc:     Alexandre Ghiti <alexghiti@...osinc.com>
Subject: [PATCH -fixes 2/2] riscv: Do not set initial_boot_params to the linear address of the dtb

Now that the dtb early mapping was moved in the fixmap region, we can
keep using this address since it is present in swapper_pg_dir, so remove
the dtb relocation which was wrong anyway since early_memremap is
restricted to 256K whereas the maximum fdt size is 2MB.

Signed-off-by: Alexandre Ghiti <alexghiti@...osinc.com>
---
 arch/riscv/kernel/setup.c |  5 +----
 arch/riscv/mm/init.c      | 21 ++-------------------
 2 files changed, 3 insertions(+), 23 deletions(-)

diff --git a/arch/riscv/kernel/setup.c b/arch/riscv/kernel/setup.c
index 542eed85ad2c..a059b73f4ddb 100644
--- a/arch/riscv/kernel/setup.c
+++ b/arch/riscv/kernel/setup.c
@@ -278,10 +278,7 @@ void __init setup_arch(char **cmdline_p)
 #if IS_ENABLED(CONFIG_BUILTIN_DTB)
 	unflatten_and_copy_device_tree();
 #else
-	if (early_init_dt_verify(__va(XIP_FIXUP(dtb_early_pa))))
-		unflatten_device_tree();
-	else
-		pr_err("No DTB found in kernel mappings\n");
+	unflatten_device_tree();
 #endif
 	misc_mem_init();
 
diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
index fb78d6bbabae..0f14f4a8d179 100644
--- a/arch/riscv/mm/init.c
+++ b/arch/riscv/mm/init.c
@@ -249,25 +249,8 @@ static void __init setup_bootmem(void)
 	 * early_init_fdt_reserve_self() since __pa() does
 	 * not work for DTB pointers that are fixmap addresses
 	 */
-	if (!IS_ENABLED(CONFIG_BUILTIN_DTB)) {
-		/*
-		 * In case the DTB is not located in a memory region we won't
-		 * be able to locate it later on via the linear mapping and
-		 * get a segfault when accessing it via __va(dtb_early_pa).
-		 * To avoid this situation copy DTB to a memory region.
-		 * Note that memblock_phys_alloc will also reserve DTB region.
-		 */
-		if (!memblock_is_memory(dtb_early_pa)) {
-			size_t fdt_size = fdt_totalsize(dtb_early_va);
-			phys_addr_t new_dtb_early_pa = memblock_phys_alloc(fdt_size, PAGE_SIZE);
-			void *new_dtb_early_va = early_memremap(new_dtb_early_pa, fdt_size);
-
-			memcpy(new_dtb_early_va, dtb_early_va, fdt_size);
-			early_memunmap(new_dtb_early_va, fdt_size);
-			_dtb_early_pa = new_dtb_early_pa;
-		} else
-			memblock_reserve(dtb_early_pa, fdt_totalsize(dtb_early_va));
-	}
+	if (!IS_ENABLED(CONFIG_BUILTIN_DTB))
+		memblock_reserve(dtb_early_pa, fdt_totalsize(dtb_early_va));
 
 	dma_contiguous_reserve(dma32_phys_limit);
 	if (IS_ENABLED(CONFIG_64BIT))
-- 
2.37.2