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-rw-r--r--src/cpu/x86/16bit/entry16.ld26
1 files changed, 23 insertions, 3 deletions
diff --git a/src/cpu/x86/16bit/entry16.ld b/src/cpu/x86/16bit/entry16.ld
index 66bfbd58ca..b5c1592691 100644
--- a/src/cpu/x86/16bit/entry16.ld
+++ b/src/cpu/x86/16bit/entry16.ld
@@ -1,3 +1,23 @@
- gdtptr16_offset = gdtptr16 & 0xffff;
- nullidt_offset = nullidt & 0xffff;
- ap_sipi_vector_in_rom = (_start16bit >> 12) & 0xff;
+/*
+ * This file is part of the coreboot project.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+gdtptr16_offset = gdtptr16 & 0xffff;
+nullidt_offset = nullidt & 0xffff;
+
+/* Symbol _start16bit must be aligned to 4kB to start AP CPUs with
+ * Startup IPI message without RAM.
+ */
+#if CONFIG(SIPI_VECTOR_IN_ROM)
+_bogus = ASSERT((_start16bit & 0xfff) == 0, "Symbol _start16bit is not at 4 KiB boundary");
+ap_sipi_vector_in_rom = (_start16bit >> 12) & 0xff;
+#endif