From: Ross Philipson <ross.philipson@oracle.com>
To: linux-kernel@vger.kernel.org, x86@kernel.org,
linux-integrity@vger.kernel.org, linux-doc@vger.kernel.org,
linux-crypto@vger.kernel.org, iommu@lists.linux-foundation.org,
kexec@lists.infradead.org, linux-efi@vger.kernel.org
Cc: ross.philipson@oracle.com, dpsmith@apertussolutions.com,
tglx@linutronix.de, mingo@redhat.com, bp@alien8.de,
hpa@zytor.com, ardb@kernel.org, mjg59@srcf.ucam.org,
James.Bottomley@hansenpartnership.com, luto@amacapital.net,
nivedita@alum.mit.edu, kanth.ghatraju@oracle.com,
trenchboot-devel@googlegroups.com
Subject: [PATCH v6 01/14] x86/boot: Place kernel_info at a fixed offset
Date: Thu, 4 May 2023 14:50:10 +0000 [thread overview]
Message-ID: <20230504145023.835096-2-ross.philipson@oracle.com> (raw)
In-Reply-To: <20230504145023.835096-1-ross.philipson@oracle.com>
From: Arvind Sankar <nivedita@alum.mit.edu>
There are use cases for storing the offset of a symbol in kernel_info.
For example, the trenchboot series [0] needs to store the offset of the
Measured Launch Environment header in kernel_info.
Since commit (note: commit ID from tip/master)
commit 527afc212231 ("x86/boot: Check that there are no run-time relocations")
run-time relocations are not allowed in the compressed kernel, so simply
using the symbol in kernel_info, as
.long symbol
will cause a linker error because this is not position-independent.
With kernel_info being a separate object file and in a different section
from startup_32, there is no way to calculate the offset of a symbol
from the start of the image in a position-independent way.
To enable such use cases, put kernel_info into its own section which is
placed at a predetermined offset (KERNEL_INFO_OFFSET) via the linker
script. This will allow calculating the symbol offset in a
position-independent way, by adding the offset from the start of
kernel_info to KERNEL_INFO_OFFSET.
Ensure that kernel_info is aligned, and use the SYM_DATA.* macros
instead of bare labels. This stores the size of the kernel_info
structure in the ELF symbol table.
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Cc: Ross Philipson <ross.philipson@oracle.com>
Signed-off-by: Ross Philipson <ross.philipson@oracle.com>
---
arch/x86/boot/compressed/kernel_info.S | 19 +++++++++++++++----
arch/x86/boot/compressed/kernel_info.h | 12 ++++++++++++
arch/x86/boot/compressed/vmlinux.lds.S | 6 ++++++
3 files changed, 33 insertions(+), 4 deletions(-)
create mode 100644 arch/x86/boot/compressed/kernel_info.h
diff --git a/arch/x86/boot/compressed/kernel_info.S b/arch/x86/boot/compressed/kernel_info.S
index f818ee8..c18f071 100644
--- a/arch/x86/boot/compressed/kernel_info.S
+++ b/arch/x86/boot/compressed/kernel_info.S
@@ -1,12 +1,23 @@
/* SPDX-License-Identifier: GPL-2.0 */
+#include <linux/linkage.h>
#include <asm/bootparam.h>
+#include "kernel_info.h"
- .section ".rodata.kernel_info", "a"
+/*
+ * If a field needs to hold the offset of a symbol from the start
+ * of the image, use the macro below, eg
+ * .long rva(symbol)
+ * This will avoid creating run-time relocations, which are not
+ * allowed in the compressed kernel.
+ */
+
+#define rva(X) (((X) - kernel_info) + KERNEL_INFO_OFFSET)
- .global kernel_info
+ .section ".rodata.kernel_info", "a"
-kernel_info:
+ .balign 16
+SYM_DATA_START(kernel_info)
/* Header, Linux top (structure). */
.ascii "LToP"
/* Size. */
@@ -19,4 +30,4 @@ kernel_info:
kernel_info_var_len_data:
/* Empty for time being... */
-kernel_info_end:
+SYM_DATA_END_LABEL(kernel_info, SYM_L_LOCAL, kernel_info_end)
diff --git a/arch/x86/boot/compressed/kernel_info.h b/arch/x86/boot/compressed/kernel_info.h
new file mode 100644
index 0000000..c127f84
--- /dev/null
+++ b/arch/x86/boot/compressed/kernel_info.h
@@ -0,0 +1,12 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef BOOT_COMPRESSED_KERNEL_INFO_H
+#define BOOT_COMPRESSED_KERNEL_INFO_H
+
+#ifdef CONFIG_X86_64
+#define KERNEL_INFO_OFFSET 0x500
+#else /* 32-bit */
+#define KERNEL_INFO_OFFSET 0x100
+#endif
+
+#endif /* BOOT_COMPRESSED_KERNEL_INFO_H */
diff --git a/arch/x86/boot/compressed/vmlinux.lds.S b/arch/x86/boot/compressed/vmlinux.lds.S
index b22f34b..265c88f 100644
--- a/arch/x86/boot/compressed/vmlinux.lds.S
+++ b/arch/x86/boot/compressed/vmlinux.lds.S
@@ -7,6 +7,7 @@ OUTPUT_FORMAT(CONFIG_OUTPUT_FORMAT)
#include <asm/cache.h>
#include <asm/page_types.h>
+#include "kernel_info.h"
#ifdef CONFIG_X86_64
OUTPUT_ARCH(i386:x86-64)
@@ -27,6 +28,11 @@ SECTIONS
HEAD_TEXT
_ehead = . ;
}
+ .rodata.kernel_info KERNEL_INFO_OFFSET : {
+ *(.rodata.kernel_info)
+ }
+ ASSERT(ABSOLUTE(kernel_info) == KERNEL_INFO_OFFSET, "kernel_info at bad address!")
+
.rodata..compressed : {
*(.rodata..compressed)
}
--
1.8.3.1
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next prev parent reply other threads:[~2023-05-04 14:51 UTC|newest]
Thread overview: 100+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-05-04 14:50 [PATCH v6 00/14] x86: Trenchboot secure dynamic launch Linux kernel support Ross Philipson
2023-05-04 14:50 ` Ross Philipson [this message]
2023-05-04 14:50 ` [PATCH v6 02/14] Documentation/x86: Secure Launch kernel documentation Ross Philipson
2023-05-05 16:19 ` Simon Horman
2023-05-05 17:32 ` Ross Philipson
2023-05-06 8:48 ` Bagas Sanjaya
2023-05-10 15:41 ` Ross Philipson
2023-05-12 10:47 ` Matthew Garrett
2023-06-16 16:44 ` Daniel P. Smith
2023-06-16 16:54 ` Matthew Garrett
2023-06-16 18:21 ` Daniel P. Smith
2023-05-12 13:19 ` Thomas Gleixner
2023-05-04 14:50 ` [PATCH v6 03/14] x86: Secure Launch Kconfig Ross Philipson
2023-05-04 14:50 ` [PATCH v6 04/14] x86: Secure Launch Resource Table header file Ross Philipson
2023-05-05 16:22 ` Simon Horman
2023-05-05 17:34 ` Ross Philipson
2023-05-10 23:04 ` Jarkko Sakkinen
2023-05-15 20:58 ` Daniel P. Smith
2023-05-12 10:55 ` Matthew Garrett
2023-05-15 21:15 ` Daniel P. Smith
2023-05-15 21:22 ` Matthew Garrett
2023-05-16 0:41 ` Daniel P. Smith
2023-05-16 1:43 ` Matthew Garrett
2023-06-16 20:01 ` Daniel P. Smith
2023-06-16 20:15 ` Matthew Garrett
2023-07-07 19:31 ` Daniel P. Smith
2023-05-04 14:50 ` [PATCH v6 05/14] x86: Secure Launch main " Ross Philipson
2023-05-05 16:25 ` Simon Horman
2023-05-05 17:37 ` Ross Philipson
2023-05-12 11:00 ` Matthew Garrett
2023-05-12 16:10 ` Ross Philipson
2023-10-31 21:37 ` ross.philipson
2023-05-04 14:50 ` [PATCH v6 06/14] x86: Add early SHA support for Secure Launch early measurements Ross Philipson
2023-05-05 16:34 ` Simon Horman
2023-05-09 16:09 ` Daniel P. Smith
2023-05-10 1:21 ` Eric Biggers
2023-05-10 22:28 ` Jarkko Sakkinen
2023-05-12 11:04 ` Matthew Garrett
2023-05-12 11:18 ` Ard Biesheuvel
2023-05-12 11:28 ` Matthew Garrett
2023-05-12 11:58 ` Ard Biesheuvel
2023-05-12 12:24 ` Andrew Cooper
2023-05-14 18:18 ` Eric Biggers
2023-05-14 19:11 ` Matthew Garrett
2023-05-12 13:24 ` Thomas Gleixner
2023-05-12 16:13 ` Matthew Garrett
2023-05-12 18:17 ` Thomas Gleixner
2023-05-12 19:12 ` Matthew Garrett
2023-05-12 19:42 ` Andrew Cooper
2023-05-15 21:23 ` Daniel P. Smith
2023-05-11 3:33 ` Herbert Xu
2023-05-16 0:50 ` Daniel P. Smith
2023-05-04 14:50 ` [PATCH v6 07/14] x86: Secure Launch kernel early boot stub Ross Philipson
2023-05-05 17:47 ` Simon Horman
2023-05-05 18:58 ` Ross Philipson
2023-05-05 19:46 ` Simon Horman
2023-05-12 11:26 ` Matthew Garrett
2023-05-12 16:17 ` Ross Philipson
2023-05-12 16:27 ` Matthew Garrett
2023-05-16 1:11 ` Daniel P. Smith
2023-05-16 1:45 ` Matthew Garrett
2023-06-15 18:00 ` Ross Philipson
2023-05-12 18:04 ` Thomas Gleixner
2023-05-15 20:13 ` Ross Philipson
2023-09-20 21:40 ` ross.philipson
2023-05-04 14:50 ` [PATCH v6 08/14] x86: Secure Launch kernel late " Ross Philipson
2023-05-05 17:52 ` Simon Horman
2023-05-05 18:59 ` Ross Philipson
2023-05-10 23:02 ` Jarkko Sakkinen
2023-05-12 15:58 ` Ross Philipson
2023-05-24 2:55 ` Jarkko Sakkinen
2023-05-12 15:44 ` Thomas Gleixner
2023-05-15 20:06 ` Ross Philipson
2023-05-04 14:50 ` [PATCH v6 09/14] x86: Secure Launch SMP bringup support Ross Philipson
2023-05-05 17:54 ` Simon Horman
2023-05-05 18:59 ` Ross Philipson
2023-05-10 22:55 ` Jarkko Sakkinen
2023-05-11 16:21 ` Ross Philipson
2023-05-12 18:02 ` Thomas Gleixner
2023-05-15 20:19 ` Ross Philipson
2023-05-04 14:50 ` [PATCH v6 10/14] kexec: Secure Launch kexec SEXIT support Ross Philipson
2023-05-04 14:50 ` [PATCH v6 11/14] reboot: Secure Launch SEXIT support on reboot paths Ross Philipson
2023-05-12 11:40 ` Matthew Garrett
2023-05-15 18:16 ` Ross Philipson
2023-05-16 1:23 ` Daniel P. Smith
2023-05-04 14:50 ` [PATCH v6 12/14] x86: Secure Launch late initcall platform module Ross Philipson
2023-05-05 19:42 ` Simon Horman
2023-05-08 15:07 ` Ross Philipson
2023-05-10 22:39 ` Jarkko Sakkinen
2023-05-12 15:53 ` Ross Philipson
2023-05-10 22:40 ` Jarkko Sakkinen
2023-05-12 15:54 ` Ross Philipson
2023-05-04 14:50 ` [PATCH v6 13/14] tpm: Allow locality 2 to be set when initializing the TPM for Secure Launch Ross Philipson
2023-05-12 11:43 ` Matthew Garrett
2023-05-12 16:22 ` Ross Philipson
2023-05-16 1:37 ` Daniel P. Smith
2023-05-04 14:50 ` [PATCH v6 14/14] x86: EFI stub DRTM launch support " Ross Philipson
2023-05-05 8:39 ` [PATCH v6 00/14] x86: Trenchboot secure dynamic launch Linux kernel support Bagas Sanjaya
2023-05-05 15:45 ` Ross Philipson
2023-05-06 7:56 ` Bagas Sanjaya
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