linux-stable/arch/arm/kernel/vmlinux.lds.S

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License cleanup: add SPDX GPL-2.0 license identifier to files with no license Many source files in the tree are missing licensing information, which makes it harder for compliance tools to determine the correct license. By default all files without license information are under the default license of the kernel, which is GPL version 2. Update the files which contain no license information with the 'GPL-2.0' SPDX license identifier. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. How this work was done: Patches were generated and checked against linux-4.14-rc6 for a subset of the use cases: - file had no licensing information it it. - file was a */uapi/* one with no licensing information in it, - file was a */uapi/* one with existing licensing information, Further patches will be generated in subsequent months to fix up cases where non-standard license headers were used, and references to license had to be inferred by heuristics based on keywords. The analysis to determine which SPDX License Identifier to be applied to a file was done in a spreadsheet of side by side results from of the output of two independent scanners (ScanCode & Windriver) producing SPDX tag:value files created by Philippe Ombredanne. Philippe prepared the base worksheet, and did an initial spot review of a few 1000 files. The 4.13 kernel was the starting point of the analysis with 60,537 files assessed. Kate Stewart did a file by file comparison of the scanner results in the spreadsheet to determine which SPDX license identifier(s) to be applied to the file. She confirmed any determination that was not immediately clear with lawyers working with the Linux Foundation. Criteria used to select files for SPDX license identifier tagging was: - Files considered eligible had to be source code files. - Make and config files were included as candidates if they contained >5 lines of source - File already had some variant of a license header in it (even if <5 lines). All documentation files were explicitly excluded. The following heuristics were used to determine which SPDX license identifiers to apply. - when both scanners couldn't find any license traces, file was considered to have no license information in it, and the top level COPYING file license applied. For non */uapi/* files that summary was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 11139 and resulted in the first patch in this series. If that file was a */uapi/* path one, it was "GPL-2.0 WITH Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 WITH Linux-syscall-note 930 and resulted in the second patch in this series. - if a file had some form of licensing information in it, and was one of the */uapi/* ones, it was denoted with the Linux-syscall-note if any GPL family license was found in the file or had no licensing in it (per prior point). Results summary: SPDX license identifier # files ---------------------------------------------------|------ GPL-2.0 WITH Linux-syscall-note 270 GPL-2.0+ WITH Linux-syscall-note 169 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17 LGPL-2.1+ WITH Linux-syscall-note 15 GPL-1.0+ WITH Linux-syscall-note 14 ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5 LGPL-2.0+ WITH Linux-syscall-note 4 LGPL-2.1 WITH Linux-syscall-note 3 ((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3 ((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1 and that resulted in the third patch in this series. - when the two scanners agreed on the detected license(s), that became the concluded license(s). - when there was disagreement between the two scanners (one detected a license but the other didn't, or they both detected different licenses) a manual inspection of the file occurred. - In most cases a manual inspection of the information in the file resulted in a clear resolution of the license that should apply (and which scanner probably needed to revisit its heuristics). - When it was not immediately clear, the license identifier was confirmed with lawyers working with the Linux Foundation. - If there was any question as to the appropriate license identifier, the file was flagged for further research and to be revisited later in time. In total, over 70 hours of logged manual review was done on the spreadsheet to determine the SPDX license identifiers to apply to the source files by Kate, Philippe, Thomas and, in some cases, confirmation by lawyers working with the Linux Foundation. Kate also obtained a third independent scan of the 4.13 code base from FOSSology, and compared selected files where the other two scanners disagreed against that SPDX file, to see if there was new insights. The Windriver scanner is based on an older version of FOSSology in part, so they are related. Thomas did random spot checks in about 500 files from the spreadsheets for the uapi headers and agreed with SPDX license identifier in the files he inspected. For the non-uapi files Thomas did random spot checks in about 15000 files. In initial set of patches against 4.14-rc6, 3 files were found to have copy/paste license identifier errors, and have been fixed to reflect the correct identifier. Additionally Philippe spent 10 hours this week doing a detailed manual inspection and review of the 12,461 patched files from the initial patch version early this week with: - a full scancode scan run, collecting the matched texts, detected license ids and scores - reviewing anything where there was a license detected (about 500+ files) to ensure that the applied SPDX license was correct - reviewing anything where there was no detection but the patch license was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied SPDX license was correct This produced a worksheet with 20 files needing minor correction. This worksheet was then exported into 3 different .csv files for the different types of files to be modified. These .csv files were then reviewed by Greg. Thomas wrote a script to parse the csv files and add the proper SPDX tag to the file, in the format that the file expected. This script was further refined by Greg based on the output to detect more types of files automatically and to distinguish between header and source .c files (which need different comment types.) Finally Greg ran the script using the .csv files to generate the patches. Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-11-01 14:07:57 +00:00
/* SPDX-License-Identifier: GPL-2.0 */
/* ld script to make ARM Linux kernel
* taken from the i386 version by Russell King
* Written by Martin Mares <mj@atrey.karlin.mff.cuni.cz>
*/
#ifdef CONFIG_XIP_KERNEL
#include "vmlinux-xip.lds.S"
#else
mm: reorder includes after introduction of linux/pgtable.h The replacement of <asm/pgrable.h> with <linux/pgtable.h> made the include of the latter in the middle of asm includes. Fix this up with the aid of the below script and manual adjustments here and there. import sys import re if len(sys.argv) is not 3: print "USAGE: %s <file> <header>" % (sys.argv[0]) sys.exit(1) hdr_to_move="#include <linux/%s>" % sys.argv[2] moved = False in_hdrs = False with open(sys.argv[1], "r") as f: lines = f.readlines() for _line in lines: line = _line.rstrip(' ') if line == hdr_to_move: continue if line.startswith("#include <linux/"): in_hdrs = True elif not moved and in_hdrs: moved = True print hdr_to_move print line Signed-off-by: Mike Rapoport <rppt@linux.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Cain <bcain@codeaurora.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Chris Zankel <chris@zankel.net> Cc: "David S. Miller" <davem@davemloft.net> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Greentime Hu <green.hu@gmail.com> Cc: Greg Ungerer <gerg@linux-m68k.org> Cc: Guan Xuetao <gxt@pku.edu.cn> Cc: Guo Ren <guoren@kernel.org> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Helge Deller <deller@gmx.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Ley Foon Tan <ley.foon.tan@intel.com> Cc: Mark Salter <msalter@redhat.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Matt Turner <mattst88@gmail.com> Cc: Max Filippov <jcmvbkbc@gmail.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Michal Simek <monstr@monstr.eu> Cc: Nick Hu <nickhu@andestech.com> Cc: Paul Walmsley <paul.walmsley@sifive.com> Cc: Richard Weinberger <richard@nod.at> Cc: Rich Felker <dalias@libc.org> Cc: Russell King <linux@armlinux.org.uk> Cc: Stafford Horne <shorne@gmail.com> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tony Luck <tony.luck@intel.com> Cc: Vincent Chen <deanbo422@gmail.com> Cc: Vineet Gupta <vgupta@synopsys.com> Cc: Will Deacon <will@kernel.org> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Link: http://lkml.kernel.org/r/20200514170327.31389-4-rppt@kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-06-09 04:32:42 +00:00
#include <linux/pgtable.h>
#include <asm/vmlinux.lds.h>
#include <asm/cache.h>
#include <asm/thread_info.h>
#include <asm/memory.h>
#include <asm/mpu.h>
#include <asm/page.h>
OUTPUT_ARCH(arm)
ENTRY(stext)
#ifndef __ARMEB__
jiffies = jiffies_64;
#else
jiffies = jiffies_64 + 4;
#endif
SECTIONS
{
/*
ARM: fix vmlinux.lds.S discarding sections We are seeing linker errors caused by sections being discarded, despite the linker script trying to keep them. The result is (eg): `.exit.text' referenced in section `.alt.smp.init' of drivers/built-in.o: defined in discarded section `.exit.text' of drivers/built-in.o `.exit.text' referenced in section `.alt.smp.init' of net/built-in.o: defined in discarded section `.exit.text' of net/built-in.o This is the relevent part of the linker script (reformatted to make it clearer): | SECTIONS | { | /* | * unwind exit sections must be discarded before the rest of the | * unwind sections get included. | */ | /DISCARD/ : { | *(.ARM.exidx.exit.text) | *(.ARM.extab.exit.text) | } | ... | .exit.text : { | *(.exit.text) | *(.memexit.text) | } | ... | /DISCARD/ : { | *(.exit.text) | *(.memexit.text) | *(.exit.data) | *(.memexit.data) | *(.memexit.rodata) | *(.exitcall.exit) | *(.discard) | *(.discard.*) | } | } Now, this is what the linker manual says about discarded output sections: | The special output section name `/DISCARD/' may be used to discard | input sections. Any input sections which are assigned to an output | section named `/DISCARD/' are not included in the output file. No questions, no exceptions. It doesn't say "unless they are listed before the /DISCARD/ section." Now, this is what asn-generic/vmlinux.lds.S says: | /* | * Default discarded sections. | * | * Some archs want to discard exit text/data at runtime rather than | * link time due to cross-section references such as alt instructions, | * bug table, eh_frame, etc. DISCARDS must be the last of output | * section definitions so that such archs put those in earlier section | * definitions. | */ And guess what - the list _always_ includes .exit.text etc. Now, what's actually happening is that the linker is reading the script, and it finds the first /DISCARD/ output section at the beginning of the script. It continues reading the script, and finds the 'DISCARD' macro at the end, which having been postprocessed results in another /DISCARD/ output section. As the linker already contains the earlier /DISCARD/ output section, it adds it to that existing section, so it effectively is placed at the start. This can be seen by using the -M option to ld: | Linker script and memory map | | 0xc037c080 jiffies = jiffies_64 | | /DISCARD/ | *(.ARM.exidx.exit.text) | *(.ARM.extab.exit.text) | *(.exit.text) | *(.memexit.text) | *(.exit.data) | *(.memexit.data) | *(.memexit.rodata) | *(.exitcall.exit) | *(.discard) | *(.discard.*) | | 0xc0008000 . = 0xc0008000 | | .head.text 0xc0008000 0x1d0 | 0xc0008000 _text = . | *(.head.text) | .head.text 0xc0008000 0x1d0 arch/arm/kernel/head.o | 0xc0008000 stext | | .text 0xc0008200 0x2d78d0 | 0xc0008200 _stext = . | 0xc0008200 __exception_text_start = . | *(.exception.text) | .exception.text | ... As you can see, all the discarded sections are grouped together - and as a result of it being the first output section, they all appear before any other section. The result is that not only is the unwind information discarded (as intended), but also the .exit.text, despite us wanting to have the .exit.text preserved. We can't move the unwind information elsewhere, because it'll then be included even when we do actually discard the .exit.text (and similar) sections. So, work around this by avoiding the generic DISCARDS macro, and instead conditionalize the sections to be discarded ourselves. This avoids the ambiguity in how the linker assigns input sections to output sections, making our script less dependent on undocumented linker behaviour. Reported-by: Rob Herring <robherring2@gmail.com> Tested-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2011-09-20 22:35:15 +00:00
* XXX: The linker does not define how output sections are
* assigned to input sections when there are multiple statements
* matching the same input section name. There is no documented
* order of matching.
*
* unwind exit sections must be discarded before the rest of the
* unwind sections get included.
*/
/DISCARD/ : {
ARM_DISCARD
#ifndef CONFIG_SMP_ON_UP
*(.alt.smp.init)
arm/build: Always handle .ARM.exidx and .ARM.extab sections After turning on warnings for orphan section placement, enabling CONFIG_UNWINDER_FRAME_POINTER instead of CONFIG_UNWINDER_ARM causes thousands of warnings when clang + ld.lld are used: $ scripts/config --file arch/arm/configs/multi_v7_defconfig \ -d CONFIG_UNWINDER_ARM \ -e CONFIG_UNWINDER_FRAME_POINTER $ make -skj"$(nproc)" ARCH=arm CROSS_COMPILE=arm-linux-gnueabi- LLVM=1 defconfig zImage ld.lld: warning: init/built-in.a(main.o):(.ARM.extab) is being placed in '.ARM.extab' ld.lld: warning: init/built-in.a(main.o):(.ARM.extab.init.text) is being placed in '.ARM.extab.init.text' ld.lld: warning: init/built-in.a(main.o):(.ARM.extab.ref.text) is being placed in '.ARM.extab.ref.text' ld.lld: warning: init/built-in.a(do_mounts.o):(.ARM.extab.init.text) is being placed in '.ARM.extab.init.text' ld.lld: warning: init/built-in.a(do_mounts.o):(.ARM.extab) is being placed in '.ARM.extab' ld.lld: warning: init/built-in.a(do_mounts_rd.o):(.ARM.extab.init.text) is being placed in '.ARM.extab.init.text' ld.lld: warning: init/built-in.a(do_mounts_rd.o):(.ARM.extab) is being placed in '.ARM.extab' ld.lld: warning: init/built-in.a(do_mounts_initrd.o):(.ARM.extab.init.text) is being placed in '.ARM.extab.init.text' ld.lld: warning: init/built-in.a(initramfs.o):(.ARM.extab.init.text) is being placed in '.ARM.extab.init.text' ld.lld: warning: init/built-in.a(initramfs.o):(.ARM.extab) is being placed in '.ARM.extab' ld.lld: warning: init/built-in.a(calibrate.o):(.ARM.extab.init.text) is being placed in '.ARM.extab.init.text' ld.lld: warning: init/built-in.a(calibrate.o):(.ARM.extab) is being placed in '.ARM.extab' These sections are handled by the ARM_UNWIND_SECTIONS define, which is only added to the list of sections when CONFIG_ARM_UNWIND is set. CONFIG_ARM_UNWIND is a hidden symbol that is only selected when CONFIG_UNWINDER_ARM is set so CONFIG_UNWINDER_FRAME_POINTER never handles these sections. According to the help text of CONFIG_UNWINDER_ARM, these sections should be discarded so that the kernel image size is not affected. Fixes: 5a17850e251a ("arm/build: Warn on orphan section placement") Link: https://github.com/ClangBuiltLinux/linux/issues/1152 Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: Nathan Chancellor <natechancellor@gmail.com> Review-by: Nick Desaulniers <ndesaulniers@google.com> Tested-by: Nick Desaulniers <ndesaulniers@google.com> [kees: Made the discard slightly more specific] Signed-off-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20200928224854.3224862-1-natechancellor@gmail.com
2020-09-28 22:48:54 +00:00
#endif
#ifndef CONFIG_ARM_UNWIND
*(.ARM.exidx) *(.ARM.exidx.*)
*(.ARM.extab) *(.ARM.extab.*)
#endif
}
. = KERNEL_OFFSET + TEXT_OFFSET;
.head.text : {
_text = .;
HEAD_TEXT
}
#ifdef CONFIG_STRICT_KERNEL_RWX
. = ALIGN(1<<SECTION_SHIFT);
#endif
#ifdef CONFIG_ARM_MPU
. = ALIGN(PMSAv8_MINALIGN);
#endif
.text : { /* Real text segment */
_stext = .; /* Text and read-only data */
ARM_TEXT
}
ARM: 8501/1: mm: flip priority of CONFIG_DEBUG_RODATA The use of CONFIG_DEBUG_RODATA is generally seen as an essential part of kernel self-protection: http://www.openwall.com/lists/kernel-hardening/2015/11/30/13 Additionally, its name has grown to mean things beyond just rodata. To get ARM closer to this, we ought to rearrange the names of the configs that control how the kernel protects its memory. What was called CONFIG_ARM_KERNMEM_PERMS is realy doing the work that other architectures call CONFIG_DEBUG_RODATA. This redefines CONFIG_DEBUG_RODATA to actually do the bulk of the ROing (and NXing). In the place of the old CONFIG_DEBUG_RODATA, use CONFIG_DEBUG_ALIGN_RODATA, since that's what the option does: adds section alignment for making rodata explicitly NX, as arm does not split the page tables like arm64 does without _ALIGN_RODATA. Also adds human readable names to the sections so I could more easily debug my typos, and makes CONFIG_DEBUG_RODATA default "y" for CPU_V7. Results in /sys/kernel/debug/kernel_page_tables for each config state: # CONFIG_DEBUG_RODATA is not set # CONFIG_DEBUG_ALIGN_RODATA is not set ---[ Kernel Mapping ]--- 0x80000000-0x80900000 9M RW x SHD 0x80900000-0xa0000000 503M RW NX SHD CONFIG_DEBUG_RODATA=y CONFIG_DEBUG_ALIGN_RODATA=y ---[ Kernel Mapping ]--- 0x80000000-0x80100000 1M RW NX SHD 0x80100000-0x80700000 6M ro x SHD 0x80700000-0x80a00000 3M ro NX SHD 0x80a00000-0xa0000000 502M RW NX SHD CONFIG_DEBUG_RODATA=y # CONFIG_DEBUG_ALIGN_RODATA is not set ---[ Kernel Mapping ]--- 0x80000000-0x80100000 1M RW NX SHD 0x80100000-0x80a00000 9M ro x SHD 0x80a00000-0xa0000000 502M RW NX SHD Signed-off-by: Kees Cook <keescook@chromium.org> Reviewed-by: Laura Abbott <labbott@fedoraproject.org> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2016-01-26 00:19:36 +00:00
#ifdef CONFIG_DEBUG_ALIGN_RODATA
. = ALIGN(1<<SECTION_SHIFT);
#endif
_etext = .; /* End of text section */
RO_DATA(PAGE_SIZE)
. = ALIGN(4);
__ex_table : AT(ADDR(__ex_table) - LOAD_OFFSET) {
__start___ex_table = .;
ARM_MMU_KEEP(*(__ex_table))
__stop___ex_table = .;
}
#ifdef CONFIG_ARM_UNWIND
ARM_UNWIND_SECTIONS
#endif
#ifdef CONFIG_STRICT_KERNEL_RWX
. = ALIGN(1<<SECTION_SHIFT);
#else
. = ALIGN(PAGE_SIZE);
#endif
__init_begin = .;
ARM_VECTORS
INIT_TEXT_SECTION(8)
.exit.text : {
ARM_EXIT_KEEP(EXIT_TEXT)
}
.init.proc.info : {
ARM_CPU_DISCARD(PROC_INFO)
}
.init.arch.info : {
__arch_info_begin = .;
*(.arch.info.init)
__arch_info_end = .;
}
.init.tagtable : {
__tagtable_begin = .;
*(.taglist.init)
__tagtable_end = .;
}
#ifdef CONFIG_SMP_ON_UP
.init.smpalt : {
__smpalt_begin = .;
*(.alt.smp.init)
__smpalt_end = .;
}
#endif
.init.pv_table : {
ARM: P2V: introduce phys_to_virt/virt_to_phys runtime patching This idea came from Nicolas, Eric Miao produced an initial version, which was then rewritten into this. Patch the physical to virtual translations at runtime. As we modify the code, this makes it incompatible with XIP kernels, but allows us to achieve this with minimal loss of performance. As many translations are of the form: physical = virtual + (PHYS_OFFSET - PAGE_OFFSET) virtual = physical - (PHYS_OFFSET - PAGE_OFFSET) we generate an 'add' instruction for __virt_to_phys(), and a 'sub' instruction for __phys_to_virt(). We calculate at run time (PHYS_OFFSET - PAGE_OFFSET) by comparing the address prior to MMU initialization with where it should be once the MMU has been initialized, and place this constant into the above add/sub instructions. Once we have (PHYS_OFFSET - PAGE_OFFSET), we can calculate the real PHYS_OFFSET as PAGE_OFFSET is a build-time constant, and save this for the C-mode PHYS_OFFSET variable definition to use. At present, we are unable to support Realview with Sparsemem enabled as this uses a complex mapping function, and MSM as this requires a constant which will not fit in our math instruction. Add a module version magic string for this feature to prevent incompatible modules being loaded. Tested-by: Tony Lindgren <tony@atomide.com> Reviewed-by: Nicolas Pitre <nicolas.pitre@linaro.org> Tested-by: Nicolas Pitre <nicolas.pitre@linaro.org> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2011-01-04 19:09:43 +00:00
__pv_table_begin = .;
*(.pv_table)
ARM: P2V: introduce phys_to_virt/virt_to_phys runtime patching This idea came from Nicolas, Eric Miao produced an initial version, which was then rewritten into this. Patch the physical to virtual translations at runtime. As we modify the code, this makes it incompatible with XIP kernels, but allows us to achieve this with minimal loss of performance. As many translations are of the form: physical = virtual + (PHYS_OFFSET - PAGE_OFFSET) virtual = physical - (PHYS_OFFSET - PAGE_OFFSET) we generate an 'add' instruction for __virt_to_phys(), and a 'sub' instruction for __phys_to_virt(). We calculate at run time (PHYS_OFFSET - PAGE_OFFSET) by comparing the address prior to MMU initialization with where it should be once the MMU has been initialized, and place this constant into the above add/sub instructions. Once we have (PHYS_OFFSET - PAGE_OFFSET), we can calculate the real PHYS_OFFSET as PAGE_OFFSET is a build-time constant, and save this for the C-mode PHYS_OFFSET variable definition to use. At present, we are unable to support Realview with Sparsemem enabled as this uses a complex mapping function, and MSM as this requires a constant which will not fit in our math instruction. Add a module version magic string for this feature to prevent incompatible modules being loaded. Tested-by: Tony Lindgren <tony@atomide.com> Reviewed-by: Nicolas Pitre <nicolas.pitre@linaro.org> Tested-by: Nicolas Pitre <nicolas.pitre@linaro.org> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2011-01-04 19:09:43 +00:00
__pv_table_end = .;
}
INIT_DATA_SECTION(16)
.exit.data : {
ARM_EXIT_KEEP(EXIT_DATA)
}
ARM: 7428/1: Prevent KALLSYM size mismatch on ARM. ARM builds seem to be plagued by an occasional build error: Inconsistent kallsyms data This is a bug - please report about it Try "make KALLSYMS_EXTRA_PASS=1" as a workaround The problem has to do with alignment of some sections by the linker. The kallsyms data is built in two passes by first linking the kernel without it, and then linking the kernel again with the symbols included. Normally, this just shifts the symbols, without changing their order, and the compression used by the kallsyms gives the same result. On non SMP, the per CPU data is empty. Depending on the where the alignment ends up, it can come out as either: +-------------------+ | last text segment | +-------------------+ /* padding */ +-------------------+ <- L1_CACHE_BYTES alignemnt | per cpu (empty) | +-------------------+ __per_cpu_end: /* padding */ __data_loc: +-------------------+ <- THREAD_SIZE alignment | data | +-------------------+ or +-------------------+ | last text segment | +-------------------+ /* padding */ +-------------------+ <- L1_CACHE_BYTES alignemnt | per cpu (empty) | +-------------------+ __per_cpu_end: /* no padding */ __data_loc: +-------------------+ <- THREAD_SIZE alignment | data | +-------------------+ if the alignment satisfies both. Because symbols that have the same address are sorted by 'nm -n', the second case will be in a different order than the first case. This changes the compression, changing the size of the kallsym data, causing the build failure. The KALLSYMS_EXTRA_PASS=1 workaround usually works, but it is still possible to have the alignment change between the second and third pass. It's probably even possible for it to never reach a fixedpoint. The problem only occurs on non-SMP, when the per-cpu data is empty, and when the data segment has alignment (and immediately follows the text segments). Fix this by only including the per_cpu section on SMP, when it is not empty. Signed-off-by: David Brown <davidb@codeaurora.org> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2012-06-20 21:52:24 +00:00
#ifdef CONFIG_SMP
PERCPU_SECTION(L1_CACHE_BYTES)
ARM: 7428/1: Prevent KALLSYM size mismatch on ARM. ARM builds seem to be plagued by an occasional build error: Inconsistent kallsyms data This is a bug - please report about it Try "make KALLSYMS_EXTRA_PASS=1" as a workaround The problem has to do with alignment of some sections by the linker. The kallsyms data is built in two passes by first linking the kernel without it, and then linking the kernel again with the symbols included. Normally, this just shifts the symbols, without changing their order, and the compression used by the kallsyms gives the same result. On non SMP, the per CPU data is empty. Depending on the where the alignment ends up, it can come out as either: +-------------------+ | last text segment | +-------------------+ /* padding */ +-------------------+ <- L1_CACHE_BYTES alignemnt | per cpu (empty) | +-------------------+ __per_cpu_end: /* padding */ __data_loc: +-------------------+ <- THREAD_SIZE alignment | data | +-------------------+ or +-------------------+ | last text segment | +-------------------+ /* padding */ +-------------------+ <- L1_CACHE_BYTES alignemnt | per cpu (empty) | +-------------------+ __per_cpu_end: /* no padding */ __data_loc: +-------------------+ <- THREAD_SIZE alignment | data | +-------------------+ if the alignment satisfies both. Because symbols that have the same address are sorted by 'nm -n', the second case will be in a different order than the first case. This changes the compression, changing the size of the kallsym data, causing the build failure. The KALLSYMS_EXTRA_PASS=1 workaround usually works, but it is still possible to have the alignment change between the second and third pass. It's probably even possible for it to never reach a fixedpoint. The problem only occurs on non-SMP, when the per-cpu data is empty, and when the data segment has alignment (and immediately follows the text segments). Fix this by only including the per_cpu section on SMP, when it is not empty. Signed-off-by: David Brown <davidb@codeaurora.org> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2012-06-20 21:52:24 +00:00
#endif
#ifdef CONFIG_HAVE_TCM
ARM_TCM
#endif
#ifdef CONFIG_STRICT_KERNEL_RWX
. = ALIGN(1<<SECTION_SHIFT);
#else
. = ALIGN(THREAD_SIZE);
#endif
__init_end = .;
_sdata = .;
RW_DATA(L1_CACHE_BYTES, PAGE_SIZE, THREAD_SIZE)
_edata = .;
BSS_SECTION(0, 0, 0)
#ifdef CONFIG_ARM_MPU
. = ALIGN(PMSAv8_MINALIGN);
#endif
_end = .;
STABS_DEBUG
DWARF_DEBUG
ARM_DETAILS
ARM_ASSERTS
}
#ifdef CONFIG_STRICT_KERNEL_RWX
/*
* Without CONFIG_DEBUG_ALIGN_RODATA, __start_rodata_section_aligned will
* be the first section-aligned location after __start_rodata. Otherwise,
* it will be equal to __start_rodata.
*/
__start_rodata_section_aligned = ALIGN(__start_rodata, 1 << SECTION_SHIFT);
#endif
/*
* These must never be empty
* If you have to comment these two assert statements out, your
* binutils is too old (for other reasons as well)
*/
ASSERT((__proc_info_end - __proc_info_begin), "missing CPU support")
ASSERT((__arch_info_end - __arch_info_begin), "no machine record defined")
#endif /* CONFIG_XIP_KERNEL */