kernel/linux.git/arch/arm/include/asm/module.h, branch v6.18.21

ARM: 9252/1: module: Teach unwinder about PLTs

2022-11-07T14:18:59+00:00

"unwind: Index not found eef26358" warnings keep popping up on CONFIG_ARM_MODULE_PLTS-enabled systems if the PC points to a PLT veneer. Teach the unwinder how to deal with them, taking into account they don't change state of the stack or register file except loading PC. Link: https://lore.kernel.org/linux-arm-kernel/20200402153845.30985-1-kursad.oney@broadcom.com/ Tested-by: Kursad Oney Reviewed-by: Linus Walleij Signed-off-by: Alexander Sverdlin Signed-off-by: Russell King (Oracle)

ARM: 9204/2: module: Add all unwind tables when load module

2022-05-20T11:34:55+00:00

For EABI stack unwinding, when loading .ko module the EXIDX sections will be added to a unwind_table list. However not all EXIDX sections are added because EXIDX sections are searched by hardcoded section names. For functions in other sections such as .ref.text or .kprobes.text, gcc generates seprated EXIDX sections (such as .ARM.exidx.ref.text or .ARM.exidx.kprobes.text). These extra EXIDX sections are not loaded, so when unwinding functions in these sections, we will failed with: unwind: Index not found xxx To fix that, I refactor the code for searching and adding EXIDX sections: - Check section type to search EXIDX tables (0x70000001) instead of strcmp() the hardcoded names. Then find the corresponding text sections by their section names. - Add a unwind_table list in module->arch to save their own unwind_table instead of the fixed-lenth array. - Save .ARM.exidx.init.text section ptr, because it should be cleaned after module init. Now all EXIDX sections of .ko can be added correctly. Signed-off-by: Chen Zhongjin Acked-by: Linus Walleij Signed-off-by: Russell King (Oracle)

ARM: 9079/1: ftrace: Add MODULE_PLTS support

2021-06-07T11:56:20+00:00

Teach ftrace_make_call() and ftrace_make_nop() about PLTs. Teach PLT code about FTRACE and all its callbacks. Otherwise the following might happen: ------------[ cut here ]------------ WARNING: CPU: 14 PID: 2265 at .../arch/arm/kernel/insn.c:14 __arm_gen_branch+0x83/0x8c() ... Hardware name: LSI Axxia AXM55XX [] (unwind_backtrace) from [] (show_stack+0x11/0x14) [] (show_stack) from [] (dump_stack+0x81/0xa8) [] (dump_stack) from [] (warn_slowpath_common+0x69/0x90) [] (warn_slowpath_common) from [] (warn_slowpath_null+0x17/0x1c) [] (warn_slowpath_null) from [] (__arm_gen_branch+0x83/0x8c) [] (__arm_gen_branch) from [] (ftrace_make_nop+0xf/0x24) [] (ftrace_make_nop) from [] (ftrace_process_locs+0x27b/0x3e8) [] (ftrace_process_locs) from [] (load_module+0x11e9/0x1a44) [] (load_module) from [] (SyS_finit_module+0x59/0x84) [] (SyS_finit_module) from [] (ret_fast_syscall+0x1/0x18) ---[ end trace e1b64ced7a89adcc ]--- ------------[ cut here ]------------ WARNING: CPU: 14 PID: 2265 at .../kernel/trace/ftrace.c:1979 ftrace_bug+0x1b1/0x234() ... Hardware name: LSI Axxia AXM55XX [] (unwind_backtrace) from [] (show_stack+0x11/0x14) [] (show_stack) from [] (dump_stack+0x81/0xa8) [] (dump_stack) from [] (warn_slowpath_common+0x69/0x90) [] (warn_slowpath_common) from [] (warn_slowpath_null+0x17/0x1c) [] (warn_slowpath_null) from [] (ftrace_bug+0x1b1/0x234) [] (ftrace_bug) from [] (ftrace_process_locs+0x285/0x3e8) [] (ftrace_process_locs) from [] (load_module+0x11e9/0x1a44) [] (load_module) from [] (SyS_finit_module+0x59/0x84) [] (SyS_finit_module) from [] (ret_fast_syscall+0x1/0x18) ---[ end trace e1b64ced7a89adcd ]--- ftrace failed to modify [] 0xe9ef7006 actual: 02:f0:3b:fa ftrace record flags: 0 (0) expected tramp: c0314265 Signed-off-by: Alexander Sverdlin Signed-off-by: Russell King

ARM: 9077/1: PLT: Move struct plt_entries definition to header

2021-06-07T11:56:20+00:00

No functional change, later it will be re-used in several files. Signed-off-by: Alexander Sverdlin Signed-off-by: Russell King

arch: split MODULE_ARCH_VERMAGIC definitions out to

2020-04-23T01:50:26+00:00

As the bug report [1] pointed out, must be included after . I believe we should not impose any include order restriction. We often sort include directives alphabetically, but it is just coding style convention. Technically, we can include header files in any order by making every header self-contained. Currently, arch-specific MODULE_ARCH_VERMAGIC is defined in , which is not included from . Hence, the straight-forward fix-up would be as follows: |--- a/include/linux/vermagic.h |+++ b/include/linux/vermagic.h |@@ -1,5 +1,6 @@ | /* SPDX-License-Identifier: GPL-2.0 */ | #include |+#include | | /* Simply sanity version stamp for modules. */ | #ifdef CONFIG_SMP This works enough, but for further cleanups, I split MODULE_ARCH_VERMAGIC definitions into . With this, and will be orthogonal, and the location of MODULE_ARCH_VERMAGIC definitions will be consistent. For arc and ia64, MODULE_PROC_FAMILY is only used for defining MODULE_ARCH_VERMAGIC. I squashed it. For hexagon, nds32, and xtensa, I removed entirely because they contained nothing but MODULE_ARCH_VERMAGIC definition. Kbuild will automatically generate at build-time, wrapping . [1] https://lore.kernel.org/lkml/20200411155623.GA22175@zn.tnic Reported-by: Borislav Petkov Signed-off-by: Masahiro Yamada Acked-by: Jessica Yu

ARM: module: Fix function kallsyms on Thumb-2

2018-12-14T19:27:29+00:00

Thumb-2 functions have the lowest bit set in the symbol value in the symtab. When kallsyms are generated for the vmlinux, the kallsyms are generated from the output of nm, and nm clears the lowest bit. $ arm-linux-gnueabihf-readelf -a vmlinux | grep show_interrupts 95947: 8015dc89 686 FUNC GLOBAL DEFAULT 2 show_interrupts $ arm-linux-gnueabihf-nm vmlinux | grep show_interrupts 8015dc88 T show_interrupts $ cat /proc/kallsyms | grep show_interrupts 8015dc88 T show_interrupts However, for modules, the kallsyms uses the values in the symbol table without modification, so for functions in modules, the lowest bit is set in kallsyms. $ arm-linux-gnueabihf-readelf -a drivers/net/tun.ko | grep tun_get_socket 333: 00002d4d 36 FUNC GLOBAL DEFAULT 1 tun_get_socket $ arm-linux-gnueabihf-nm drivers/net/tun.ko | grep tun_get_socket 00002d4c T tun_get_socket $ cat /proc/kallsyms | grep tun_get_socket 7f802d4d t tun_get_socket [tun] Because of this, the symbol+offset of the crashing instruction shown in oopses is incorrect when the crash is in a module. For example, given a tun_get_socket which starts like this, 00002d4c : 2d4c: 6943 ldr r3, [r0, #20] 2d4e: 4a07 ldr r2, [pc, #28] 2d50: 4293 cmp r3, r2 a crash when tun_get_socket is called with NULL results in: PC is at tun_xdp+0xa3/0xa4 [tun] pc : [<7f802d4c>] As can be seen, the "PC is at" line reports the wrong symbol name, and the symbol+offset will point to the wrong source line if it is passed to gdb. To solve this, add a way for archs to fixup the reading of these module kallsyms values, and use that to clear the lowest bit for function symbols on Thumb-2. After the fix: # cat /proc/kallsyms | grep tun_get_socket 7f802d4c t tun_get_socket [tun] PC is at tun_get_socket+0x0/0x24 [tun] pc : [<7f802d4c>] Signed-off-by: Vincent Whitchurch Signed-off-by: Jessica Yu

ARM: module: fix modsign build error

2018-07-09T18:29:49+00:00

The asm/module.h header file can not be included standalone, which breaks the module signing code after a recent change: In file included from kernel/module-internal.h:13, from kernel/module_signing.c:17: arch/arm/include/asm/module.h:37:27: error: 'struct module' declared inside parameter list will not be visible outside of this definition or declaration [-Werror] u32 get_module_plt(struct module *mod, unsigned long loc, Elf32_Addr val); This adds a forward declaration of struct module to make it all work. Fixes: f314dfea16a0 ("modsign: log module name in the event of an error") Signed-off-by: Arnd Bergmann Acked-by: Russell King Signed-off-by: Jessica Yu

License cleanup: add SPDX GPL-2.0 license identifier to files with no license

2017-11-02T10:10:55+00:00

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 Reviewed-by: Philippe Ombredanne Reviewed-by: Thomas Gleixner Signed-off-by: Greg Kroah-Hartman

ARM: 8662/1: module: split core and init PLT sections

2017-03-17T10:01:28+00:00

Since commit 35fa91eed817 ("ARM: kernel: merge core and init PLTs"), the ARM module PLT code allocates all PLT entries in a single core section, since the overhead of having a separate init PLT section is not justified by the small number of PLT entries usually required for init code. However, the core and init module regions are allocated independently, and there is a corner case where the core region may be allocated from the VMALLOC region if the dedicated module region is exhausted, but the init region, being much smaller, can still be allocated from the module region. This puts the PLT entries out of reach of the relocated branch instructions, defeating the whole purpose of PLTs. So split the core and init PLT regions, and name the latter ".init.plt" so it gets allocated along with (and sufficiently close to) the .init sections that it serves. Also, given that init PLT entries may need to be emitted for branches that target the core module, modify the logic that disregards defined symbols to only disregard symbols that are defined in the same section. Fixes: 35fa91eed817 ("ARM: kernel: merge core and init PLTs") Cc: # v4.9+ Reported-by: Angus Clark Tested-by: Angus Clark Signed-off-by: Ard Biesheuvel Signed-off-by: Russell King

ARM: kernel: merge core and init PLTs

2016-08-30T16:45:34+00:00

The PLT code uses a separate .init.plt section to allocate PLT entries for jump and call instructions in __init code. However, even for fairly sizable modules like mac80211.ko, we only end up with a couple of PLT entries in the .init section, and so we can simplify the code significantly by emitting all PLT entries into the same section. Tested-by: Jongsung Kim Signed-off-by: Ard Biesheuvel