1 files changed, 112 insertions, 0 deletions
diff --git a/drivers/firmware/efi/unaccepted_memory.c b/drivers/firmware/efi/unaccepted_memory.c
new file mode 100644
index 000000000000..08a9a843550a
--- /dev/null
+++ b/drivers/firmware/efi/unaccepted_memory.c
@@ -0,0 +1,112 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#include <linux/efi.h>
+#include <linux/memblock.h>
+#include <linux/spinlock.h>
+#include <asm/unaccepted_memory.h>
+
+/* Protects unaccepted memory bitmap */
+static DEFINE_SPINLOCK(unaccepted_memory_lock);
+
+/*
+ * accept_memory() -- Consult bitmap and accept the memory if needed.
+ *
+ * Only memory that is explicitly marked as unaccepted in the bitmap requires
+ * an action. All the remaining memory is implicitly accepted and doesn't need
+ * acceptance.
+ *
+ * No need to accept:
+ *  - anything if the system has no unaccepted table;
+ *  - memory that is below phys_base;
+ *  - memory that is above the memory that addressable by the bitmap;
+ */
+void accept_memory(phys_addr_t start, phys_addr_t end)
+{
+	struct efi_unaccepted_memory *unaccepted;
+	unsigned long range_start, range_end;
+	unsigned long flags;
+	u64 unit_size;
+
+	unaccepted = efi_get_unaccepted_table();
+	if (!unaccepted)
+		return;
+
+	unit_size = unaccepted->unit_size;
+
+	/*
+	 * Only care for the part of the range that is represented
+	 * in the bitmap.
+	 */
+	if (start < unaccepted->phys_base)
+		start = unaccepted->phys_base;
+	if (end < unaccepted->phys_base)
+		return;
+
+	/* Translate to offsets from the beginning of the bitmap */
+	start -= unaccepted->phys_base;
+	end -= unaccepted->phys_base;
+
+	/* Make sure not to overrun the bitmap */
+	if (end > unaccepted->size * unit_size * BITS_PER_BYTE)
+		end = unaccepted->size * unit_size * BITS_PER_BYTE;
+
+	range_start = start / unit_size;
+
+	spin_lock_irqsave(&unaccepted_memory_lock, flags);
+	for_each_set_bitrange_from(range_start, range_end, unaccepted->bitmap,
+				   DIV_ROUND_UP(end, unit_size)) {
+		unsigned long phys_start, phys_end;
+		unsigned long len = range_end - range_start;
+
+		phys_start = range_start * unit_size + unaccepted->phys_base;
+		phys_end = range_end * unit_size + unaccepted->phys_base;
+
+		arch_accept_memory(phys_start, phys_end);
+		bitmap_clear(unaccepted->bitmap, range_start, len);
+	}
+	spin_unlock_irqrestore(&unaccepted_memory_lock, flags);
+}
+
+bool range_contains_unaccepted_memory(phys_addr_t start, phys_addr_t end)
+{
+	struct efi_unaccepted_memory *unaccepted;
+	unsigned long flags;
+	bool ret = false;
+	u64 unit_size;
+
+	unaccepted = efi_get_unaccepted_table();
+	if (!unaccepted)
+		return false;
+
+	unit_size = unaccepted->unit_size;
+
+	/*
+	 * Only care for the part of the range that is represented
+	 * in the bitmap.
+	 */
+	if (start < unaccepted->phys_base)
+		start = unaccepted->phys_base;
+	if (end < unaccepted->phys_base)
+		return false;
+
+	/* Translate to offsets from the beginning of the bitmap */
+	start -= unaccepted->phys_base;
+	end -= unaccepted->phys_base;
+
+	/* Make sure not to overrun the bitmap */
+	if (end > unaccepted->size * unit_size * BITS_PER_BYTE)
+		end = unaccepted->size * unit_size * BITS_PER_BYTE;
+
+	spin_lock_irqsave(&unaccepted_memory_lock, flags);
+	while (start < end) {
+		if (test_bit(start / unit_size, unaccepted->bitmap)) {
+			ret = true;
+			break;
+		}
+
+		start += unit_size;
+	}
+	spin_unlock_irqrestore(&unaccepted_memory_lock, flags);
+
+	return ret;
+}