[RFC PATCH 1/9] memblock: Permit existing reserved regions to be marked RSRV_KERN

[Ard Biesheuvel <ardb+git@google.com>]

From: Ard Biesheuvel <ardb@kernel.org>

Permit existing memblock reservations to be marked as RSRV_KERN. This
will be used by the EFI code on x86 to distinguish between reservations
of boot services data regions that have actual significance to the
kernel and regions that are reserved temporarily to work around buggy
firmware.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
 include/linux/memblock.h |  1 +
 mm/memblock.c            | 15 +++++++++++++++
 2 files changed, 16 insertions(+)

diff --git a/include/linux/memblock.h b/include/linux/memblock.h
index 6ec5e9ac0699..9eac4f268359 100644
--- a/include/linux/memblock.h
+++ b/include/linux/memblock.h
@@ -155,6 +155,7 @@ int memblock_mark_mirror(phys_addr_t base, phys_addr_t size);
 int memblock_mark_nomap(phys_addr_t base, phys_addr_t size);
 int memblock_clear_nomap(phys_addr_t base, phys_addr_t size);
 int memblock_reserved_mark_noinit(phys_addr_t base, phys_addr_t size);
+int memblock_reserved_mark_kern(phys_addr_t base, phys_addr_t size);
 int memblock_mark_kho_scratch(phys_addr_t base, phys_addr_t size);
 int memblock_clear_kho_scratch(phys_addr_t base, phys_addr_t size);
 
diff --git a/mm/memblock.c b/mm/memblock.c
index b3ddfdec7a80..2505ce8b319c 100644
--- a/mm/memblock.c
+++ b/mm/memblock.c
@@ -1115,6 +1115,21 @@ int __init_memblock memblock_reserved_mark_noinit(phys_addr_t base, phys_addr_t
 				    MEMBLOCK_RSRV_NOINIT);
 }
 
+/**
+ * memblock_reserved_mark_kern - Mark a reserved memory region with flag
+ * MEMBLOCK_RSRV_KERN
+ *
+ * @base: the base phys addr of the region
+ * @size: the size of the region
+ *
+ * Return: 0 on success, -errno on failure.
+ */
+int __init_memblock memblock_reserved_mark_kern(phys_addr_t base, phys_addr_t size)
+{
+	return memblock_setclr_flag(&memblock.reserved, base, size, 1,
+				    MEMBLOCK_RSRV_KERN);
+}
+
 /**
  * memblock_mark_kho_scratch - Mark a memory region as MEMBLOCK_KHO_SCRATCH.
  * @base: the base phys addr of the region
-- 
2.53.0.473.g4a7958ca14-goog