of/fdt: make memblock minimum physical address arch configurable
By default, early_init_dt_add_memory_arch() ignores memory below
the base of the kernel image since it won't be addressable via the
linear mapping. However, this is not appropriate anymore once we
decouple the kernel text mapping from the linear mapping, so archs
may want to drop the low limit entirely. So allow the minimum to be
overridden by setting MIN_MEMBLOCK_ADDR.
Acked-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
index 655f79d..1f98156 100644
--- a/drivers/of/fdt.c
+++ b/drivers/of/fdt.c
@@ -976,13 +976,16 @@
}
#ifdef CONFIG_HAVE_MEMBLOCK
+#ifndef MIN_MEMBLOCK_ADDR
+#define MIN_MEMBLOCK_ADDR __pa(PAGE_OFFSET)
+#endif
#ifndef MAX_MEMBLOCK_ADDR
#define MAX_MEMBLOCK_ADDR ((phys_addr_t)~0)
#endif
void __init __weak early_init_dt_add_memory_arch(u64 base, u64 size)
{
- const u64 phys_offset = __pa(PAGE_OFFSET);
+ const u64 phys_offset = MIN_MEMBLOCK_ADDR;
if (!PAGE_ALIGNED(base)) {
if (size < PAGE_SIZE - (base & ~PAGE_MASK)) {