[PATCH v4 01/22] of/fdt: make memblock minimum physical address arch configurable

From: Ard Biesheuvel
Date: Tue Jan 26 2016 - 12:17:51 EST

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@xxxxxxx>
Acked-by: Rob Herring <robh@xxxxxxxxxx>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
drivers/of/fdt.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
index 655f79db7899..1f98156f8996 100644
--- a/drivers/of/fdt.c
+++ b/drivers/of/fdt.c
@@ -976,13 +976,16 @@ int __init early_init_dt_scan_chosen(unsigned long node, const char *uname,

#define MAX_MEMBLOCK_ADDR ((phys_addr_t)~0)

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)) {