arm64: Ignore memory blocks below PHYS_OFFSET

According to Documentation/arm64/booting.txt, the kernel image must be loaded at a pre-defined offset from the start of RAM so that the kernel can calculate PHYS_OFFSET based on this address. If the DT contains memory blocks below this PHYS_OFFSET, report them and ignore the corresponding memory range. Signed-off-by: Catalin Marinas <[email protected]>
pllopis · Oct 18, 2012 · f71a1a4 · f71a1a4
1 parent c60b0c2
commit f71a1a4
Showing 1 changed file with 12 additions and 0 deletions.
diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
@@ -170,7 +170,19 @@ static void __init setup_machine_fdt(phys_addr_t dt_phys)
 
 void __init early_init_dt_add_memory_arch(u64 base, u64 size)
 {
+	base &= PAGE_MASK;
 	size &= PAGE_MASK;
+	if (base + size < PHYS_OFFSET) {
+		pr_warning("Ignoring memory block 0x%llx - 0x%llx\n",
+			   base, base + size);
+		return;
+	}
+	if (base < PHYS_OFFSET) {
+		pr_warning("Ignoring memory range 0x%llx - 0x%llx\n",
+			   base, PHYS_OFFSET);
+		size -= PHYS_OFFSET - base;
+		base = PHYS_OFFSET;
+	}
 	memblock_add(base, size);
 }