linux-kernel - [PATCH RFC 2/2] x86/boot: Introduce dummy MLE header

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Date:   Fri, 24 May 2019 11:55:04 +0200
From:   Daniel Kiper <daniel.kiper@...cle.com>
To:     linux-kernel@...r.kernel.org, x86@...nel.org
Cc:     dpsmith@...rtussolutions.com, eric.snowberg@...cle.com,
        hpa@...or.com, kanth.ghatraju@...cle.com, konrad.wilk@...cle.com,
        ross.philipson@...cle.com
Subject: [PATCH RFC 2/2] x86/boot: Introduce dummy MLE header

DO NOT APPLY!!!

THIS PATCH INTRODUCES DUMMY MLE HEADER AND SIMPLY ILLUSTRATES HOW TO
EXTEND THE setup_header2 PROPERLY.

DO NOT APPLY!!!

Signed-off-by: Ross Philipson <ross.philipson@...cle.com>
Signed-off-by: Daniel Kiper <daniel.kiper@...cle.com>
Reviewed-by: Ross Philipson <ross.philipson@...cle.com>
---
 Documentation/x86/boot.txt               |  6 ++++++
 arch/x86/Kconfig                         |  7 +++++++
 arch/x86/boot/compressed/Makefile        |  1 +
 arch/x86/boot/compressed/setup_header2.S |  6 ++++++
 arch/x86/boot/compressed/sl_stub.S       | 28 ++++++++++++++++++++++++++++
 5 files changed, 48 insertions(+)
 create mode 100644 arch/x86/boot/compressed/sl_stub.S

diff --git a/Documentation/x86/boot.txt b/Documentation/x86/boot.txt
index ff10c6116662..09cf50d7dca2 100644
--- a/Documentation/x86/boot.txt
+++ b/Documentation/x86/boot.txt
@@ -793,6 +793,12 @@ Offset/size:	0x0004/4
   This field contains the size of the setup_header2 including setup_header2.header.
   It should be used by the boot loader to detect supported fields in the setup_header2.
 
+Field name:	mle_header_offset
+Offset/size:	0x0008/4
+
+  This field contains the MLE header offset from the beginning of the kernel image.
+  If it is set to zero then it means that MLE header is not build into the kernel.
+
 
 **** THE IMAGE CHECKSUM
 
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 5ad92419be19..021e274ede54 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -1961,6 +1961,13 @@ config EFI_MIXED
 
 	   If unsure, say N.
 
+config SECURE_LAUNCH_STUB
+       bool "Secure Launch stub support"
+       depends on X86_64
+       ---help---
+         This kernel feature allows a bzImage to be loaded directly
+         through Intel TXT or AMD SKINIT measured launch.
+
 config SECCOMP
 	def_bool y
 	prompt "Enable seccomp to safely compute untrusted bytecode"
diff --git a/arch/x86/boot/compressed/Makefile b/arch/x86/boot/compressed/Makefile
index c12ccc2bd923..9722d119e19a 100644
--- a/arch/x86/boot/compressed/Makefile
+++ b/arch/x86/boot/compressed/Makefile
@@ -78,6 +78,7 @@ vmlinux-objs-y := $(obj)/vmlinux.lds $(obj)/setup_header2.o $(obj)/head_$(BITS).
 
 vmlinux-objs-$(CONFIG_EARLY_PRINTK) += $(obj)/early_serial_console.o
 vmlinux-objs-$(CONFIG_RANDOMIZE_BASE) += $(obj)/kaslr.o
+vmlinux-objs-$(CONFIG_SECURE_LAUNCH_STUB) += $(obj)/sl_stub.o
 ifdef CONFIG_X86_64
 	vmlinux-objs-$(CONFIG_RANDOMIZE_BASE) += $(obj)/kaslr_64.o
 	vmlinux-objs-y += $(obj)/mem_encrypt.o
diff --git a/arch/x86/boot/compressed/setup_header2.S b/arch/x86/boot/compressed/setup_header2.S
index 0b3963296825..eb732626fd22 100644
--- a/arch/x86/boot/compressed/setup_header2.S
+++ b/arch/x86/boot/compressed/setup_header2.S
@@ -9,4 +9,10 @@ setup_header2:
 	.ascii	"hDR2"
         /* Size. */
 	.long	setup_header2_end - setup_header2
+        /* MLE header offset. */
+#ifdef CONFIG_SECURE_LAUNCH_STUB
+	.long	mle_header
+#else
+	.long	0
+#endif
 setup_header2_end:
diff --git a/arch/x86/boot/compressed/sl_stub.S b/arch/x86/boot/compressed/sl_stub.S
new file mode 100644
index 000000000000..34f5000528e4
--- /dev/null
+++ b/arch/x86/boot/compressed/sl_stub.S
@@ -0,0 +1,28 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+/*
+ * Copyright (c) 2019 Oracle and/or its affiliates. All rights reserved.
+ *
+ * Author(s):
+ *     Ross Philipson <ross.philipson@...cle.com>
+ */
+	.code32
+	.text
+
+	/* The MLE Header per the TXT Specification, section 4.1 */
+	.global	mle_header
+
+mle_header:
+	.long	0x9082ac5a    /* UUID0 */
+	.long	0x74a7476f    /* UUID1 */
+	.long	0xa2555c0f    /* UUID2 */
+	.long	0x42b651cb    /* UUID3 */
+	.long	0x00000034    /* MLE header size */
+	.long	0x00020002    /* MLE version 2.2 */
+	.long	0x01234567    /* Linear entry point of MLE (virt. address) */
+	.long	0x00000000    /* First valid page of MLE */
+	.long	0x00000000    /* Offset within binary of first byte of MLE */
+	.long	0x00000000    /* Offset within binary of last byte + 1 of MLE */
+	.long	0x00000223    /* Bit vector of MLE-supported capabilities */
+	.long	0x00000000    /* Starting linear address of command line */
+	.long	0x00000000    /* Ending linear address of command line */
-- 
2.11.0