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Diffstat (limited to 'drivers/firmware/efi/x86_fake_mem.c')
-rw-r--r--drivers/firmware/efi/x86_fake_mem.c75
1 files changed, 75 insertions, 0 deletions
diff --git a/drivers/firmware/efi/x86_fake_mem.c b/drivers/firmware/efi/x86_fake_mem.c
new file mode 100644
index 000000000..0bafcc1bb
--- /dev/null
+++ b/drivers/firmware/efi/x86_fake_mem.c
@@ -0,0 +1,75 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright(c) 2019 Intel Corporation. All rights reserved. */
+#include <linux/efi.h>
+#include <asm/e820/api.h>
+#include "fake_mem.h"
+
+void __init efi_fake_memmap_early(void)
+{
+ int i;
+
+ /*
+ * The late efi_fake_mem() call can handle all requests if
+ * EFI_MEMORY_SP support is disabled.
+ */
+ if (!efi_soft_reserve_enabled())
+ return;
+
+ if (!efi_enabled(EFI_MEMMAP) || !nr_fake_mem)
+ return;
+
+ /*
+ * Given that efi_fake_memmap() needs to perform memblock
+ * allocations it needs to run after e820__memblock_setup().
+ * However, if efi_fake_mem specifies EFI_MEMORY_SP for a given
+ * address range that potentially needs to mark the memory as
+ * reserved prior to e820__memblock_setup(). Update e820
+ * directly if EFI_MEMORY_SP is specified for an
+ * EFI_CONVENTIONAL_MEMORY descriptor.
+ */
+ for (i = 0; i < nr_fake_mem; i++) {
+ struct efi_mem_range *mem = &efi_fake_mems[i];
+ efi_memory_desc_t *md;
+ u64 m_start, m_end;
+
+ if ((mem->attribute & EFI_MEMORY_SP) == 0)
+ continue;
+
+ m_start = mem->range.start;
+ m_end = mem->range.end;
+ for_each_efi_memory_desc(md) {
+ u64 start, end, size;
+
+ if (md->type != EFI_CONVENTIONAL_MEMORY)
+ continue;
+
+ start = md->phys_addr;
+ end = md->phys_addr + (md->num_pages << EFI_PAGE_SHIFT) - 1;
+
+ if (m_start <= end && m_end >= start)
+ /* fake range overlaps descriptor */;
+ else
+ continue;
+
+ /*
+ * Trim the boundary of the e820 update to the
+ * descriptor in case the fake range overlaps
+ * !EFI_CONVENTIONAL_MEMORY
+ */
+ start = max(start, m_start);
+ end = min(end, m_end);
+ size = end - start + 1;
+
+ if (end <= start)
+ continue;
+
+ /*
+ * Ensure each efi_fake_mem instance results in
+ * a unique e820 resource
+ */
+ e820__range_remove(start, size, E820_TYPE_RAM, 1);
+ e820__range_add(start, size, E820_TYPE_SOFT_RESERVED);
+ e820__update_table(e820_table);
+ }
+ }
+}