From: Mike Rapoport <rppt@xxxxxxxxxxxxxxxxxx>
Subject: of: ignore sub-page memory regions
Memory region size is rounded down to page boundary and with sub-page
region it becomes 0 and there is no point to add an empty region.
Moreover, when the base is less than PAGE_SIZE we get a bogus size as
(base + size - 1) evaluates to -1.
8cccffc52694 ("of: check for size < 0 after rounding in
early_init_dt_add_memory_arch") introduced a test for wrap around for the
case when base is not page aligned, the same test can be used to ignore
sub-page region sizes.
Link: http://lkml.kernel.org/r/1533326330-31677-3-git-send-email-rppt@xxxxxxxxxxxxxxxxxx
Signed-off-by: Mike Rapoport <rppt@xxxxxxxxxxxxxxxxxx>
Reviewed-by: Rob Herring <robh@xxxxxxxxxx>
Cc: Guan Xuetao <gxt@xxxxxxxxxx>
Cc: Ley Foon Tan <ley.foon.tan@xxxxxxxxx>
Cc: Richard Kuo <rkuo@xxxxxxxxxxxxxx>
Cc: Richard Weinberger <richard@xxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/of/fdt.c | 11 ++++++-----
1 file changed, 6 insertions(+), 5 deletions(-)
--- a/drivers/of/fdt.c~of-ignore-sub-page-memory-regions
+++ a/drivers/of/fdt.c
@@ -1127,12 +1127,13 @@ void __init __weak early_init_dt_add_mem
{
const u64 phys_offset = MIN_MEMBLOCK_ADDR;
+ if (size < PAGE_SIZE - (base & ~PAGE_MASK)) {
+ pr_warn("Ignoring memory block 0x%llx - 0x%llx\n",
+ base, base + size);
+ return;
+ }
+
if (!PAGE_ALIGNED(base)) {
- if (size < PAGE_SIZE - (base & ~PAGE_MASK)) {
- pr_warn("Ignoring memory block 0x%llx - 0x%llx\n",
- base, base + size);
- return;
- }
size -= PAGE_SIZE - (base & ~PAGE_MASK);
base = PAGE_ALIGN(base);
}
_
