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/*
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* Copyright (c) 2013-2023, Arm Limited and Contributors. All rights reserved.
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*
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* SPDX-License-Identifier: BSD-3-Clause
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*/
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linker_script: move .data section to bl_common.ld.h
Move the data section to the common header.
I slightly tweaked some scripts as follows:
[1] bl1.ld.S has ALIGN(16). I added DATA_ALIGN macro, which is 1
by default, but overridden by bl1.ld.S. Currently, ALIGN(16)
of the .data section is redundant because commit 412865907699
("Fix boot failures on some builds linked with ld.lld.") padded
out the previous section to work around the issue of LLD version
<= 10.0. This will be fixed in the future release of LLVM, so
I am keeping the proper way to align LMA.
[2] bl1.ld.S and bl2_el3.ld.S define __DATA_RAM_{START,END}__ instead
of __DATA_{START,END}__. I put them out of the .data section.
[3] SORT_BY_ALIGNMENT() is missing tsp.ld.S, sp_min.ld.S, and
mediatek/mt6795/bl31.ld.S. This commit adds SORT_BY_ALIGNMENT()
for all images, so the symbol order in those three will change,
but I do not think it is a big deal.
Change-Id: I215bb23c319f045cd88e6f4e8ee2518c67f03692
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
5 years ago
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/*
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* The .data section gets copied from ROM to RAM at runtime. Its LMA should be
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* 16-byte aligned to allow efficient copying of 16-bytes aligned regions in it.
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linker_script: move .data section to bl_common.ld.h
Move the data section to the common header.
I slightly tweaked some scripts as follows:
[1] bl1.ld.S has ALIGN(16). I added DATA_ALIGN macro, which is 1
by default, but overridden by bl1.ld.S. Currently, ALIGN(16)
of the .data section is redundant because commit 412865907699
("Fix boot failures on some builds linked with ld.lld.") padded
out the previous section to work around the issue of LLD version
<= 10.0. This will be fixed in the future release of LLVM, so
I am keeping the proper way to align LMA.
[2] bl1.ld.S and bl2_el3.ld.S define __DATA_RAM_{START,END}__ instead
of __DATA_{START,END}__. I put them out of the .data section.
[3] SORT_BY_ALIGNMENT() is missing tsp.ld.S, sp_min.ld.S, and
mediatek/mt6795/bl31.ld.S. This commit adds SORT_BY_ALIGNMENT()
for all images, so the symbol order in those three will change,
but I do not think it is a big deal.
Change-Id: I215bb23c319f045cd88e6f4e8ee2518c67f03692
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
5 years ago
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* Its VMA must be page-aligned as it marks the first read/write page.
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*/
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#define DATA_ALIGN 16
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#include <common/bl_common.ld.h>
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#include <lib/xlat_tables/xlat_tables_defs.h>
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OUTPUT_FORMAT(PLATFORM_LINKER_FORMAT)
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OUTPUT_ARCH(PLATFORM_LINKER_ARCH)
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ENTRY(bl1_entrypoint)
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MEMORY {
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ROM (rx): ORIGIN = BL1_RO_BASE, LENGTH = BL1_RO_LIMIT - BL1_RO_BASE
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RAM (rwx): ORIGIN = BL1_RW_BASE, LENGTH = BL1_RW_LIMIT - BL1_RW_BASE
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}
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SECTIONS {
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ROM_REGION_START = ORIGIN(ROM);
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ROM_REGION_LENGTH = LENGTH(ROM);
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RAM_REGION_START = ORIGIN(RAM);
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RAM_REGION_LENGTH = LENGTH(RAM);
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. = BL1_RO_BASE;
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ASSERT(. == ALIGN(PAGE_SIZE),
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"BL1_RO_BASE address is not aligned on a page boundary.")
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Introduce SEPARATE_CODE_AND_RODATA build flag
At the moment, all BL images share a similar memory layout: they start
with their code section, followed by their read-only data section.
The two sections are contiguous in memory. Therefore, the end of the
code section and the beginning of the read-only data one might share
a memory page. This forces both to be mapped with the same memory
attributes. As the code needs to be executable, this means that the
read-only data stored on the same memory page as the code are
executable as well. This could potentially be exploited as part of
a security attack.
This patch introduces a new build flag called
SEPARATE_CODE_AND_RODATA, which isolates the code and read-only data
on separate memory pages. This in turn allows independent control of
the access permissions for the code and read-only data.
This has an impact on memory footprint, as padding bytes need to be
introduced between the code and read-only data to ensure the
segragation of the two. To limit the memory cost, the memory layout
of the read-only section has been changed in this case.
- When SEPARATE_CODE_AND_RODATA=0, the layout is unchanged, i.e.
the read-only section still looks like this (padding omitted):
| ... |
+-------------------+
| Exception vectors |
+-------------------+
| Read-only data |
+-------------------+
| Code |
+-------------------+ BLx_BASE
In this case, the linker script provides the limits of the whole
read-only section.
- When SEPARATE_CODE_AND_RODATA=1, the exception vectors and
read-only data are swapped, such that the code and exception
vectors are contiguous, followed by the read-only data. This
gives the following new layout (padding omitted):
| ... |
+-------------------+
| Read-only data |
+-------------------+
| Exception vectors |
+-------------------+
| Code |
+-------------------+ BLx_BASE
In this case, the linker script now exports 2 sets of addresses
instead: the limits of the code and the limits of the read-only
data. Refer to the Firmware Design guide for more details. This
provides platform code with a finer-grained view of the image
layout and allows it to map these 2 regions with the appropriate
access permissions.
Note that SEPARATE_CODE_AND_RODATA applies to all BL images.
Change-Id: I936cf80164f6b66b6ad52b8edacadc532c935a49
8 years ago
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#if SEPARATE_CODE_AND_RODATA
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.text . : {
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__TEXT_START__ = .;
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|
Introduce SEPARATE_CODE_AND_RODATA build flag
At the moment, all BL images share a similar memory layout: they start
with their code section, followed by their read-only data section.
The two sections are contiguous in memory. Therefore, the end of the
code section and the beginning of the read-only data one might share
a memory page. This forces both to be mapped with the same memory
attributes. As the code needs to be executable, this means that the
read-only data stored on the same memory page as the code are
executable as well. This could potentially be exploited as part of
a security attack.
This patch introduces a new build flag called
SEPARATE_CODE_AND_RODATA, which isolates the code and read-only data
on separate memory pages. This in turn allows independent control of
the access permissions for the code and read-only data.
This has an impact on memory footprint, as padding bytes need to be
introduced between the code and read-only data to ensure the
segragation of the two. To limit the memory cost, the memory layout
of the read-only section has been changed in this case.
- When SEPARATE_CODE_AND_RODATA=0, the layout is unchanged, i.e.
the read-only section still looks like this (padding omitted):
| ... |
+-------------------+
| Exception vectors |
+-------------------+
| Read-only data |
+-------------------+
| Code |
+-------------------+ BLx_BASE
In this case, the linker script provides the limits of the whole
read-only section.
- When SEPARATE_CODE_AND_RODATA=1, the exception vectors and
read-only data are swapped, such that the code and exception
vectors are contiguous, followed by the read-only data. This
gives the following new layout (padding omitted):
| ... |
+-------------------+
| Read-only data |
+-------------------+
| Exception vectors |
+-------------------+
| Code |
+-------------------+ BLx_BASE
In this case, the linker script now exports 2 sets of addresses
instead: the limits of the code and the limits of the read-only
data. Refer to the Firmware Design guide for more details. This
provides platform code with a finer-grained view of the image
layout and allows it to map these 2 regions with the appropriate
access permissions.
Note that SEPARATE_CODE_AND_RODATA applies to all BL images.
Change-Id: I936cf80164f6b66b6ad52b8edacadc532c935a49
8 years ago
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*bl1_entrypoint.o(.text*)
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*(SORT_BY_ALIGNMENT(.text*))
|
Introduce SEPARATE_CODE_AND_RODATA build flag
At the moment, all BL images share a similar memory layout: they start
with their code section, followed by their read-only data section.
The two sections are contiguous in memory. Therefore, the end of the
code section and the beginning of the read-only data one might share
a memory page. This forces both to be mapped with the same memory
attributes. As the code needs to be executable, this means that the
read-only data stored on the same memory page as the code are
executable as well. This could potentially be exploited as part of
a security attack.
This patch introduces a new build flag called
SEPARATE_CODE_AND_RODATA, which isolates the code and read-only data
on separate memory pages. This in turn allows independent control of
the access permissions for the code and read-only data.
This has an impact on memory footprint, as padding bytes need to be
introduced between the code and read-only data to ensure the
segragation of the two. To limit the memory cost, the memory layout
of the read-only section has been changed in this case.
- When SEPARATE_CODE_AND_RODATA=0, the layout is unchanged, i.e.
the read-only section still looks like this (padding omitted):
| ... |
+-------------------+
| Exception vectors |
+-------------------+
| Read-only data |
+-------------------+
| Code |
+-------------------+ BLx_BASE
In this case, the linker script provides the limits of the whole
read-only section.
- When SEPARATE_CODE_AND_RODATA=1, the exception vectors and
read-only data are swapped, such that the code and exception
vectors are contiguous, followed by the read-only data. This
gives the following new layout (padding omitted):
| ... |
+-------------------+
| Read-only data |
+-------------------+
| Exception vectors |
+-------------------+
| Code |
+-------------------+ BLx_BASE
In this case, the linker script now exports 2 sets of addresses
instead: the limits of the code and the limits of the read-only
data. Refer to the Firmware Design guide for more details. This
provides platform code with a finer-grained view of the image
layout and allows it to map these 2 regions with the appropriate
access permissions.
Note that SEPARATE_CODE_AND_RODATA applies to all BL images.
Change-Id: I936cf80164f6b66b6ad52b8edacadc532c935a49
8 years ago
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*(.vectors)
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__TEXT_END_UNALIGNED__ = .;
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. = ALIGN(PAGE_SIZE);
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|
Introduce SEPARATE_CODE_AND_RODATA build flag
At the moment, all BL images share a similar memory layout: they start
with their code section, followed by their read-only data section.
The two sections are contiguous in memory. Therefore, the end of the
code section and the beginning of the read-only data one might share
a memory page. This forces both to be mapped with the same memory
attributes. As the code needs to be executable, this means that the
read-only data stored on the same memory page as the code are
executable as well. This could potentially be exploited as part of
a security attack.
This patch introduces a new build flag called
SEPARATE_CODE_AND_RODATA, which isolates the code and read-only data
on separate memory pages. This in turn allows independent control of
the access permissions for the code and read-only data.
This has an impact on memory footprint, as padding bytes need to be
introduced between the code and read-only data to ensure the
segragation of the two. To limit the memory cost, the memory layout
of the read-only section has been changed in this case.
- When SEPARATE_CODE_AND_RODATA=0, the layout is unchanged, i.e.
the read-only section still looks like this (padding omitted):
| ... |
+-------------------+
| Exception vectors |
+-------------------+
| Read-only data |
+-------------------+
| Code |
+-------------------+ BLx_BASE
In this case, the linker script provides the limits of the whole
read-only section.
- When SEPARATE_CODE_AND_RODATA=1, the exception vectors and
read-only data are swapped, such that the code and exception
vectors are contiguous, followed by the read-only data. This
gives the following new layout (padding omitted):
| ... |
+-------------------+
| Read-only data |
+-------------------+
| Exception vectors |
+-------------------+
| Code |
+-------------------+ BLx_BASE
In this case, the linker script now exports 2 sets of addresses
instead: the limits of the code and the limits of the read-only
data. Refer to the Firmware Design guide for more details. This
provides platform code with a finer-grained view of the image
layout and allows it to map these 2 regions with the appropriate
access permissions.
Note that SEPARATE_CODE_AND_RODATA applies to all BL images.
Change-Id: I936cf80164f6b66b6ad52b8edacadc532c935a49
8 years ago
|
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|
__TEXT_END__ = .;
|
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|
|
} >ROM
|
Introduce SEPARATE_CODE_AND_RODATA build flag
At the moment, all BL images share a similar memory layout: they start
with their code section, followed by their read-only data section.
The two sections are contiguous in memory. Therefore, the end of the
code section and the beginning of the read-only data one might share
a memory page. This forces both to be mapped with the same memory
attributes. As the code needs to be executable, this means that the
read-only data stored on the same memory page as the code are
executable as well. This could potentially be exploited as part of
a security attack.
This patch introduces a new build flag called
SEPARATE_CODE_AND_RODATA, which isolates the code and read-only data
on separate memory pages. This in turn allows independent control of
the access permissions for the code and read-only data.
This has an impact on memory footprint, as padding bytes need to be
introduced between the code and read-only data to ensure the
segragation of the two. To limit the memory cost, the memory layout
of the read-only section has been changed in this case.
- When SEPARATE_CODE_AND_RODATA=0, the layout is unchanged, i.e.
the read-only section still looks like this (padding omitted):
| ... |
+-------------------+
| Exception vectors |
+-------------------+
| Read-only data |
+-------------------+
| Code |
+-------------------+ BLx_BASE
In this case, the linker script provides the limits of the whole
read-only section.
- When SEPARATE_CODE_AND_RODATA=1, the exception vectors and
read-only data are swapped, such that the code and exception
vectors are contiguous, followed by the read-only data. This
gives the following new layout (padding omitted):
| ... |
+-------------------+
| Read-only data |
+-------------------+
| Exception vectors |
+-------------------+
| Code |
+-------------------+ BLx_BASE
In this case, the linker script now exports 2 sets of addresses
instead: the limits of the code and the limits of the read-only
data. Refer to the Firmware Design guide for more details. This
provides platform code with a finer-grained view of the image
layout and allows it to map these 2 regions with the appropriate
access permissions.
Note that SEPARATE_CODE_AND_RODATA applies to all BL images.
Change-Id: I936cf80164f6b66b6ad52b8edacadc532c935a49
8 years ago
|
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/* .ARM.extab and .ARM.exidx are only added because Clang needs them */
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.ARM.extab . : {
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*(.ARM.extab* .gnu.linkonce.armextab.*)
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} >ROM
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.ARM.exidx . : {
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*(.ARM.exidx* .gnu.linkonce.armexidx.*)
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} >ROM
|
|
|
|
|
Introduce SEPARATE_CODE_AND_RODATA build flag
At the moment, all BL images share a similar memory layout: they start
with their code section, followed by their read-only data section.
The two sections are contiguous in memory. Therefore, the end of the
code section and the beginning of the read-only data one might share
a memory page. This forces both to be mapped with the same memory
attributes. As the code needs to be executable, this means that the
read-only data stored on the same memory page as the code are
executable as well. This could potentially be exploited as part of
a security attack.
This patch introduces a new build flag called
SEPARATE_CODE_AND_RODATA, which isolates the code and read-only data
on separate memory pages. This in turn allows independent control of
the access permissions for the code and read-only data.
This has an impact on memory footprint, as padding bytes need to be
introduced between the code and read-only data to ensure the
segragation of the two. To limit the memory cost, the memory layout
of the read-only section has been changed in this case.
- When SEPARATE_CODE_AND_RODATA=0, the layout is unchanged, i.e.
the read-only section still looks like this (padding omitted):
| ... |
+-------------------+
| Exception vectors |
+-------------------+
| Read-only data |
+-------------------+
| Code |
+-------------------+ BLx_BASE
In this case, the linker script provides the limits of the whole
read-only section.
- When SEPARATE_CODE_AND_RODATA=1, the exception vectors and
read-only data are swapped, such that the code and exception
vectors are contiguous, followed by the read-only data. This
gives the following new layout (padding omitted):
| ... |
+-------------------+
| Read-only data |
+-------------------+
| Exception vectors |
+-------------------+
| Code |
+-------------------+ BLx_BASE
In this case, the linker script now exports 2 sets of addresses
instead: the limits of the code and the limits of the read-only
data. Refer to the Firmware Design guide for more details. This
provides platform code with a finer-grained view of the image
layout and allows it to map these 2 regions with the appropriate
access permissions.
Note that SEPARATE_CODE_AND_RODATA applies to all BL images.
Change-Id: I936cf80164f6b66b6ad52b8edacadc532c935a49
8 years ago
|
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|
.rodata . : {
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__RODATA_START__ = .;
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|
*(SORT_BY_ALIGNMENT(.rodata*))
|
Introduce SEPARATE_CODE_AND_RODATA build flag
At the moment, all BL images share a similar memory layout: they start
with their code section, followed by their read-only data section.
The two sections are contiguous in memory. Therefore, the end of the
code section and the beginning of the read-only data one might share
a memory page. This forces both to be mapped with the same memory
attributes. As the code needs to be executable, this means that the
read-only data stored on the same memory page as the code are
executable as well. This could potentially be exploited as part of
a security attack.
This patch introduces a new build flag called
SEPARATE_CODE_AND_RODATA, which isolates the code and read-only data
on separate memory pages. This in turn allows independent control of
the access permissions for the code and read-only data.
This has an impact on memory footprint, as padding bytes need to be
introduced between the code and read-only data to ensure the
segragation of the two. To limit the memory cost, the memory layout
of the read-only section has been changed in this case.
- When SEPARATE_CODE_AND_RODATA=0, the layout is unchanged, i.e.
the read-only section still looks like this (padding omitted):
| ... |
+-------------------+
| Exception vectors |
+-------------------+
| Read-only data |
+-------------------+
| Code |
+-------------------+ BLx_BASE
In this case, the linker script provides the limits of the whole
read-only section.
- When SEPARATE_CODE_AND_RODATA=1, the exception vectors and
read-only data are swapped, such that the code and exception
vectors are contiguous, followed by the read-only data. This
gives the following new layout (padding omitted):
| ... |
+-------------------+
| Read-only data |
+-------------------+
| Exception vectors |
+-------------------+
| Code |
+-------------------+ BLx_BASE
In this case, the linker script now exports 2 sets of addresses
instead: the limits of the code and the limits of the read-only
data. Refer to the Firmware Design guide for more details. This
provides platform code with a finer-grained view of the image
layout and allows it to map these 2 regions with the appropriate
access permissions.
Note that SEPARATE_CODE_AND_RODATA applies to all BL images.
Change-Id: I936cf80164f6b66b6ad52b8edacadc532c935a49
8 years ago
|
|
|
|
|
|
|
RODATA_COMMON
|
Introduce SEPARATE_CODE_AND_RODATA build flag
At the moment, all BL images share a similar memory layout: they start
with their code section, followed by their read-only data section.
The two sections are contiguous in memory. Therefore, the end of the
code section and the beginning of the read-only data one might share
a memory page. This forces both to be mapped with the same memory
attributes. As the code needs to be executable, this means that the
read-only data stored on the same memory page as the code are
executable as well. This could potentially be exploited as part of
a security attack.
This patch introduces a new build flag called
SEPARATE_CODE_AND_RODATA, which isolates the code and read-only data
on separate memory pages. This in turn allows independent control of
the access permissions for the code and read-only data.
This has an impact on memory footprint, as padding bytes need to be
introduced between the code and read-only data to ensure the
segragation of the two. To limit the memory cost, the memory layout
of the read-only section has been changed in this case.
- When SEPARATE_CODE_AND_RODATA=0, the layout is unchanged, i.e.
the read-only section still looks like this (padding omitted):
| ... |
+-------------------+
| Exception vectors |
+-------------------+
| Read-only data |
+-------------------+
| Code |
+-------------------+ BLx_BASE
In this case, the linker script provides the limits of the whole
read-only section.
- When SEPARATE_CODE_AND_RODATA=1, the exception vectors and
read-only data are swapped, such that the code and exception
vectors are contiguous, followed by the read-only data. This
gives the following new layout (padding omitted):
| ... |
+-------------------+
| Read-only data |
+-------------------+
| Exception vectors |
+-------------------+
| Code |
+-------------------+ BLx_BASE
In this case, the linker script now exports 2 sets of addresses
instead: the limits of the code and the limits of the read-only
data. Refer to the Firmware Design guide for more details. This
provides platform code with a finer-grained view of the image
layout and allows it to map these 2 regions with the appropriate
access permissions.
Note that SEPARATE_CODE_AND_RODATA applies to all BL images.
Change-Id: I936cf80164f6b66b6ad52b8edacadc532c935a49
8 years ago
|
|
|
|
|
|
|
/*
|
|
|
|
* No need to pad out the .rodata section to a page boundary. Next is
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|
|
|
* the .data section, which can mapped in ROM with the same memory
|
|
|
|
* attributes as the .rodata section.
|
|
|
|
*
|
|
|
|
* Pad out to 16 bytes though as .data section needs to be 16-byte
|
|
|
|
* aligned and lld does not align the LMA to the alignment specified
|
|
|
|
* on the .data section.
|
Introduce SEPARATE_CODE_AND_RODATA build flag
At the moment, all BL images share a similar memory layout: they start
with their code section, followed by their read-only data section.
The two sections are contiguous in memory. Therefore, the end of the
code section and the beginning of the read-only data one might share
a memory page. This forces both to be mapped with the same memory
attributes. As the code needs to be executable, this means that the
read-only data stored on the same memory page as the code are
executable as well. This could potentially be exploited as part of
a security attack.
This patch introduces a new build flag called
SEPARATE_CODE_AND_RODATA, which isolates the code and read-only data
on separate memory pages. This in turn allows independent control of
the access permissions for the code and read-only data.
This has an impact on memory footprint, as padding bytes need to be
introduced between the code and read-only data to ensure the
segragation of the two. To limit the memory cost, the memory layout
of the read-only section has been changed in this case.
- When SEPARATE_CODE_AND_RODATA=0, the layout is unchanged, i.e.
the read-only section still looks like this (padding omitted):
| ... |
+-------------------+
| Exception vectors |
+-------------------+
| Read-only data |
+-------------------+
| Code |
+-------------------+ BLx_BASE
In this case, the linker script provides the limits of the whole
read-only section.
- When SEPARATE_CODE_AND_RODATA=1, the exception vectors and
read-only data are swapped, such that the code and exception
vectors are contiguous, followed by the read-only data. This
gives the following new layout (padding omitted):
| ... |
+-------------------+
| Read-only data |
+-------------------+
| Exception vectors |
+-------------------+
| Code |
+-------------------+ BLx_BASE
In this case, the linker script now exports 2 sets of addresses
instead: the limits of the code and the limits of the read-only
data. Refer to the Firmware Design guide for more details. This
provides platform code with a finer-grained view of the image
layout and allows it to map these 2 regions with the appropriate
access permissions.
Note that SEPARATE_CODE_AND_RODATA applies to all BL images.
Change-Id: I936cf80164f6b66b6ad52b8edacadc532c935a49
8 years ago
|
|
|
*/
|
|
|
|
__RODATA_END_UNALIGNED__ = .;
|
Introduce SEPARATE_CODE_AND_RODATA build flag
At the moment, all BL images share a similar memory layout: they start
with their code section, followed by their read-only data section.
The two sections are contiguous in memory. Therefore, the end of the
code section and the beginning of the read-only data one might share
a memory page. This forces both to be mapped with the same memory
attributes. As the code needs to be executable, this means that the
read-only data stored on the same memory page as the code are
executable as well. This could potentially be exploited as part of
a security attack.
This patch introduces a new build flag called
SEPARATE_CODE_AND_RODATA, which isolates the code and read-only data
on separate memory pages. This in turn allows independent control of
the access permissions for the code and read-only data.
This has an impact on memory footprint, as padding bytes need to be
introduced between the code and read-only data to ensure the
segragation of the two. To limit the memory cost, the memory layout
of the read-only section has been changed in this case.
- When SEPARATE_CODE_AND_RODATA=0, the layout is unchanged, i.e.
the read-only section still looks like this (padding omitted):
| ... |
+-------------------+
| Exception vectors |
+-------------------+
| Read-only data |
+-------------------+
| Code |
+-------------------+ BLx_BASE
In this case, the linker script provides the limits of the whole
read-only section.
- When SEPARATE_CODE_AND_RODATA=1, the exception vectors and
read-only data are swapped, such that the code and exception
vectors are contiguous, followed by the read-only data. This
gives the following new layout (padding omitted):
| ... |
+-------------------+
| Read-only data |
+-------------------+
| Exception vectors |
+-------------------+
| Code |
+-------------------+ BLx_BASE
In this case, the linker script now exports 2 sets of addresses
instead: the limits of the code and the limits of the read-only
data. Refer to the Firmware Design guide for more details. This
provides platform code with a finer-grained view of the image
layout and allows it to map these 2 regions with the appropriate
access permissions.
Note that SEPARATE_CODE_AND_RODATA applies to all BL images.
Change-Id: I936cf80164f6b66b6ad52b8edacadc532c935a49
8 years ago
|
|
|
__RODATA_END__ = .;
|
|
|
|
|
|
|
|
. = ALIGN(16);
|
Introduce SEPARATE_CODE_AND_RODATA build flag
At the moment, all BL images share a similar memory layout: they start
with their code section, followed by their read-only data section.
The two sections are contiguous in memory. Therefore, the end of the
code section and the beginning of the read-only data one might share
a memory page. This forces both to be mapped with the same memory
attributes. As the code needs to be executable, this means that the
read-only data stored on the same memory page as the code are
executable as well. This could potentially be exploited as part of
a security attack.
This patch introduces a new build flag called
SEPARATE_CODE_AND_RODATA, which isolates the code and read-only data
on separate memory pages. This in turn allows independent control of
the access permissions for the code and read-only data.
This has an impact on memory footprint, as padding bytes need to be
introduced between the code and read-only data to ensure the
segragation of the two. To limit the memory cost, the memory layout
of the read-only section has been changed in this case.
- When SEPARATE_CODE_AND_RODATA=0, the layout is unchanged, i.e.
the read-only section still looks like this (padding omitted):
| ... |
+-------------------+
| Exception vectors |
+-------------------+
| Read-only data |
+-------------------+
| Code |
+-------------------+ BLx_BASE
In this case, the linker script provides the limits of the whole
read-only section.
- When SEPARATE_CODE_AND_RODATA=1, the exception vectors and
read-only data are swapped, such that the code and exception
vectors are contiguous, followed by the read-only data. This
gives the following new layout (padding omitted):
| ... |
+-------------------+
| Read-only data |
+-------------------+
| Exception vectors |
+-------------------+
| Code |
+-------------------+ BLx_BASE
In this case, the linker script now exports 2 sets of addresses
instead: the limits of the code and the limits of the read-only
data. Refer to the Firmware Design guide for more details. This
provides platform code with a finer-grained view of the image
layout and allows it to map these 2 regions with the appropriate
access permissions.
Note that SEPARATE_CODE_AND_RODATA applies to all BL images.
Change-Id: I936cf80164f6b66b6ad52b8edacadc532c935a49
8 years ago
|
|
|
} >ROM
|
|
|
|
#else /* SEPARATE_CODE_AND_RODATA */
|
|
|
|
.ro . : {
|
|
|
|
__RO_START__ = .;
|
|
|
|
|
|
|
|
*bl1_entrypoint.o(.text*)
|
|
|
|
*(SORT_BY_ALIGNMENT(.text*))
|
|
|
|
*(SORT_BY_ALIGNMENT(.rodata*))
|
|
|
|
|
|
|
|
RODATA_COMMON
|
|
|
|
|
|
|
|
*(.vectors)
|
|
|
|
|
|
|
|
__RO_END__ = .;
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Pad out to 16 bytes as the .data section needs to be 16-byte aligned
|
|
|
|
* and lld does not align the LMA to the alignment specified on the
|
|
|
|
* .data section.
|
|
|
|
*/
|
|
|
|
. = ALIGN(16);
|
|
|
|
} >ROM
|
|
|
|
#endif /* SEPARATE_CODE_AND_RODATA */
|
|
|
|
|
|
|
|
ASSERT(__CPU_OPS_END__ > __CPU_OPS_START__,
|
|
|
|
"cpu_ops not defined for this platform.")
|
|
|
|
|
|
|
|
ROM_REGION_END = .;
|
|
|
|
. = BL1_RW_BASE;
|
|
|
|
|
|
|
|
ASSERT(BL1_RW_BASE == ALIGN(PAGE_SIZE),
|
|
|
|
"BL1_RW_BASE address is not aligned on a page boundary.")
|
|
|
|
|
linker_script: move .data section to bl_common.ld.h
Move the data section to the common header.
I slightly tweaked some scripts as follows:
[1] bl1.ld.S has ALIGN(16). I added DATA_ALIGN macro, which is 1
by default, but overridden by bl1.ld.S. Currently, ALIGN(16)
of the .data section is redundant because commit 412865907699
("Fix boot failures on some builds linked with ld.lld.") padded
out the previous section to work around the issue of LLD version
<= 10.0. This will be fixed in the future release of LLVM, so
I am keeping the proper way to align LMA.
[2] bl1.ld.S and bl2_el3.ld.S define __DATA_RAM_{START,END}__ instead
of __DATA_{START,END}__. I put them out of the .data section.
[3] SORT_BY_ALIGNMENT() is missing tsp.ld.S, sp_min.ld.S, and
mediatek/mt6795/bl31.ld.S. This commit adds SORT_BY_ALIGNMENT()
for all images, so the symbol order in those three will change,
but I do not think it is a big deal.
Change-Id: I215bb23c319f045cd88e6f4e8ee2518c67f03692
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
5 years ago
|
|
|
DATA_SECTION >RAM AT>ROM
|
|
|
|
|
linker_script: move .data section to bl_common.ld.h
Move the data section to the common header.
I slightly tweaked some scripts as follows:
[1] bl1.ld.S has ALIGN(16). I added DATA_ALIGN macro, which is 1
by default, but overridden by bl1.ld.S. Currently, ALIGN(16)
of the .data section is redundant because commit 412865907699
("Fix boot failures on some builds linked with ld.lld.") padded
out the previous section to work around the issue of LLD version
<= 10.0. This will be fixed in the future release of LLVM, so
I am keeping the proper way to align LMA.
[2] bl1.ld.S and bl2_el3.ld.S define __DATA_RAM_{START,END}__ instead
of __DATA_{START,END}__. I put them out of the .data section.
[3] SORT_BY_ALIGNMENT() is missing tsp.ld.S, sp_min.ld.S, and
mediatek/mt6795/bl31.ld.S. This commit adds SORT_BY_ALIGNMENT()
for all images, so the symbol order in those three will change,
but I do not think it is a big deal.
Change-Id: I215bb23c319f045cd88e6f4e8ee2518c67f03692
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
5 years ago
|
|
|
__DATA_RAM_START__ = __DATA_START__;
|
|
|
|
__DATA_RAM_END__ = __DATA_END__;
|
|
|
|
|
|
|
|
STACK_SECTION >RAM
|
linker_script: move bss section to bl_common.ld.h
Move the bss section to the common header. This adds BAKERY_LOCK_NORMAL
and PMF_TIMESTAMP, which previously existed only in BL31. This is not
a big deal because unused data should not be compiled in the first
place. I believe this should be controlled by BL*_SOURCES in Makefiles,
not by linker scripts.
I investigated BL1, BL2, BL2U, BL31 for plat=fvp, and BL2-AT-EL3,
BL31, BL31 for plat=uniphier. I did not see any more unexpected
code addition.
The bss section has bigger alignment. I added BSS_ALIGN for this.
Currently, SORT_BY_ALIGNMENT() is missing in sp_min.ld.S, and with this
change, the BSS symbols in SP_MIN will be sorted by the alignment.
This is not a big deal (or, even better in terms of the image size).
Change-Id: I680ee61f84067a559bac0757f9d03e73119beb33
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
5 years ago
|
|
|
BSS_SECTION >RAM
|
|
|
|
XLAT_TABLE_SECTION >RAM
|
|
|
|
|
|
|
|
#if USE_COHERENT_MEM
|
|
|
|
/*
|
|
|
|
* The base address of the coherent memory section must be page-aligned to
|
|
|
|
* guarantee that the coherent data are stored on their own pages and are
|
|
|
|
* not mixed with normal data. This is required to set up the correct memory
|
|
|
|
* attributes for the coherent data page tables.
|
|
|
|
*/
|
|
|
|
.coherent_ram (NOLOAD) : ALIGN(PAGE_SIZE) {
|
|
|
|
__COHERENT_RAM_START__ = .;
|
|
|
|
*(.tzfw_coherent_mem)
|
|
|
|
__COHERENT_RAM_END_UNALIGNED__ = .;
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Memory page(s) mapped to this section will be marked as device
|
|
|
|
* memory. No other unexpected data must creep in. Ensure the rest of
|
|
|
|
* the current memory page is unused.
|
|
|
|
*/
|
|
|
|
. = ALIGN(PAGE_SIZE);
|
|
|
|
|
|
|
|
__COHERENT_RAM_END__ = .;
|
|
|
|
} >RAM
|
|
|
|
#endif /* USE_COHERENT_MEM */
|
|
|
|
|
|
|
|
__BL1_RAM_START__ = ADDR(.data);
|
|
|
|
__BL1_RAM_END__ = .;
|
|
|
|
|
|
|
|
__DATA_ROM_START__ = LOADADDR(.data);
|
|
|
|
__DATA_SIZE__ = SIZEOF(.data);
|
|
|
|
|
|
|
|
/*
|
|
|
|
* The .data section is the last PROGBITS section so its end marks the end
|
|
|
|
* of BL1's actual content in Trusted ROM.
|
|
|
|
*/
|
|
|
|
__BL1_ROM_END__ = __DATA_ROM_START__ + __DATA_SIZE__;
|
|
|
|
|
|
|
|
ASSERT(__BL1_ROM_END__ <= BL1_RO_LIMIT,
|
|
|
|
"BL1's ROM content has exceeded its limit.")
|
|
|
|
|
|
|
|
__BSS_SIZE__ = SIZEOF(.bss);
|
|
|
|
|
|
|
|
#if USE_COHERENT_MEM
|
|
|
|
__COHERENT_RAM_UNALIGNED_SIZE__ =
|
|
|
|
__COHERENT_RAM_END_UNALIGNED__ - __COHERENT_RAM_START__;
|
|
|
|
#endif /* USE_COHERENT_MEM */
|
|
|
|
|
|
|
|
ASSERT(. <= BL1_RW_LIMIT, "BL1's RW section has exceeded its limit.")
|
|
|
|
RAM_REGION_END = .;
|
|
|
|
}
|