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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 15:07:57 +01:00
/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __ASM_LSE_H
#define __ASM_LSE_H
#include <asm/atomic_ll_sc.h>
#ifdef CONFIG_ARM64_LSE_ATOMICS
arm64: lse: Fix LSE atomics with LLVM Commit e0d5896bd356 ("arm64: lse: fix LSE atomics with LLVM's integrated assembler") broke the build when clang is used in connjunction with the binutils assembler ("-no-integrated-as"). This happens because __LSE_PREAMBLE is defined as ".arch armv8-a+lse", which overrides the version of the CPU architecture passed via the "-march" paramter to gas: $ aarch64-none-linux-gnu-as -EL -I ./arch/arm64/include -I ./arch/arm64/include/generated -I ./include -I ./include -I ./arch/arm64/include/uapi -I ./arch/arm64/include/generated/uapi -I ./include/uapi -I ./include/generated/uapi -I ./init -I ./init -march=armv8.3-a -o init/do_mounts.o /tmp/do_mounts-d7992a.s /tmp/do_mounts-d7992a.s: Assembler messages: /tmp/do_mounts-d7992a.s:1959: Error: selected processor does not support `autiasp' /tmp/do_mounts-d7992a.s:2021: Error: selected processor does not support `paciasp' /tmp/do_mounts-d7992a.s:2157: Error: selected processor does not support `autiasp' /tmp/do_mounts-d7992a.s:2175: Error: selected processor does not support `paciasp' /tmp/do_mounts-d7992a.s:2494: Error: selected processor does not support `autiasp' Fix the issue by replacing ".arch armv8-a+lse" with ".arch_extension lse". Sami confirms that the clang integrated assembler does now support the '.arch_extension' directive, so this change will be fine even for LTO builds in future. Fixes: e0d5896bd356cd ("arm64: lse: fix LSE atomics with LLVM's integrated assembler") Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will@kernel.org> Reported-by: Amit Kachhap <Amit.Kachhap@arm.com> Tested-by: Sami Tolvanen <samitolvanen@google.com> Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com> Signed-off-by: Will Deacon <will@kernel.org>
2020-02-18 16:49:06 +00:00
#define __LSE_PREAMBLE ".arch_extension lse\n"
#include <linux/compiler_types.h>
#include <linux/export.h>
#include <linux/stringify.h>
#include <asm/alternative.h>
arm64: alternatives: add alternative_has_feature_*() Currrently we use a mixture of alternative sequences and static branches to handle features detected at boot time. For ease of maintenance we generally prefer to use static branches in C code, but this has a few downsides: * Each static branch has metadata in the __jump_table section, which is not discarded after features are finalized. This wastes some space, and slows down the patching of other static branches. * The static branches are patched at a different point in time from the alternatives, so changes are not atomic. This leaves a transient period where there could be a mismatch between the behaviour of alternatives and static branches, which could be problematic for some features (e.g. pseudo-NMI). * More (instrumentable) kernel code is executed to patch each static branch, which can be risky when patching certain features (e.g. irqflags management for pseudo-NMI). * When CONFIG_JUMP_LABEL=n, static branches are turned into a load of a flag and a conditional branch. This means it isn't safe to use such static branches in an alternative address space (e.g. the NVHE/PKVM hyp code), where the generated address isn't safe to acccess. To deal with these issues, this patch introduces new alternative_has_feature_*() helpers, which work like static branches but are patched using alternatives. This ensures the patching is performed at the same time as other alternative patching, allows the metadata to be freed after patching, and is safe for use in alternative address spaces. Note that all supported toolchains have asm goto support, and since commit: a0a12c3ed057af57 ("asm goto: eradicate CC_HAS_ASM_GOTO)" ... the CC_HAS_ASM_GOTO Kconfig symbol has been removed, so no feature check is necessary, and we can always make use of asm goto. Additionally, note that: * This has no impact on cpus_have_cap(), which is a dynamic check. * This has no functional impact on cpus_have_const_cap(). The branches are patched slightly later than before this patch, but these branches are not reachable until caps have been finalised. * It is now invalid to use cpus_have_final_cap() in the window between feature detection and patching. All existing uses are only expected after patching anyway, so this should not be a problem. * The LSE atomics will now be enabled during alternatives patching rather than immediately before. As the LL/SC an LSE atomics are functionally equivalent this should not be problematic. When building defconfig with GCC 12.1.0, the resulting Image is 64KiB smaller: | % ls -al Image-* | -rw-r--r-- 1 mark mark 37108224 Aug 23 09:56 Image-after | -rw-r--r-- 1 mark mark 37173760 Aug 23 09:54 Image-before According to bloat-o-meter.pl: | add/remove: 44/34 grow/shrink: 602/1294 up/down: 39692/-61108 (-21416) | Function old new delta | [...] | Total: Before=16618336, After=16596920, chg -0.13% | add/remove: 0/2 grow/shrink: 0/0 up/down: 0/-1296 (-1296) | Data old new delta | arm64_const_caps_ready 16 - -16 | cpu_hwcap_keys 1280 - -1280 | Total: Before=8987120, After=8985824, chg -0.01% | add/remove: 0/0 grow/shrink: 0/0 up/down: 0/0 (0) | RO Data old new delta | Total: Before=18408, After=18408, chg +0.00% Signed-off-by: Mark Rutland <mark.rutland@arm.com> Cc: Ard Biesheuvel <ardb@kernel.org> Cc: James Morse <james.morse@arm.com> Cc: Joey Gouly <joey.gouly@arm.com> Cc: Marc Zyngier <maz@kernel.org> Cc: Will Deacon <will@kernel.org> Reviewed-by: Ard Biesheuvel <ardb@kernel.org> Link: https://lore.kernel.org/r/20220912162210.3626215-8-mark.rutland@arm.com Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2022-09-12 17:22:09 +01:00
#include <asm/alternative-macros.h>
#include <asm/atomic_lse.h>
#include <asm/cpucaps.h>
arm64: atomics: remove redundant static branch Due to a historical oversight, we emit a redundant static branch for each atomic/atomic64 operation when CONFIG_ARM64_LSE_ATOMICS is selected. We can safely remove this, making the kernel Image reasonably smaller. When CONFIG_ARM64_LSE_ATOMICS is selected, every LSE atomic operation has two preceding static branches with the same target, e.g. b f7c <kernel_init_freeable+0xa4> b f7c <kernel_init_freeable+0xa4> mov w0, #0x1 // #1 ldadd w0, w0, [x19] This is because the __lse_ll_sc_body() wrapper uses system_uses_lse_atomics(), which checks both `arm64_const_caps_ready` and `cpu_hwcap_keys[ARM64_HAS_LSE_ATOMICS]`, each of which emits a static branch. This has been the case since commit: addfc38672c73efd ("arm64: atomics: avoid out-of-line ll/sc atomics") However, there was never a need to check `arm64_const_caps_ready`, which was itself introduced in commit: 63a1e1c95e60e798 ("arm64/cpufeature: don't use mutex in bringup path") ... so that cpus_have_const_cap() could fall back to checking the `cpu_hwcaps` bitmap prior to the static keys for individual caps becoming enabled. As system_uses_lse_atomics() doesn't check `cpu_hwcaps`, and doesn't need to as we can safely use the LL/SC atomics prior to enabling the `ARM64_HAS_LSE_ATOMICS` static key, it doesn't need to check `arm64_const_caps_ready`. This patch removes the `arm64_const_caps_ready` check from system_uses_lse_atomics(). As the arch_atomic_* routines are meant to be safely usable in noinstr code, I've also marked system_uses_lse_atomics() as __always_inline. This results in one fewer static branch per atomic operation, with the prior example becoming: b f78 <kernel_init_freeable+0xa0> mov w0, #0x1 // #1 ldadd w0, w0, [x19] Each static branch consists of the branch itself and an associated __jump_table entry. Removing these has a reasonable impact on the Image size, with a GCC 11.1.0 defconfig v5.17-rc2 Image being reduced by 128KiB: | [mark@lakrids:~/src/linux]% ls -al Image* | -rw-r--r-- 1 mark mark 34619904 Feb 3 18:24 Image.baseline | -rw-r--r-- 1 mark mark 34488832 Feb 3 18:33 Image.onebranch Signed-off-by: Mark Rutland <mark.rutland@arm.com> Cc: Ard Biesheuvel <ardb@kernel.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Suzuki Poulose <suzuki.poulose@arm.com> Cc: Will Deacon <will@kernel.org> Link: https://lore.kernel.org/r/20220204104439.270567-1-mark.rutland@arm.com Signed-off-by: Will Deacon <will@kernel.org>
2022-02-04 10:44:39 +00:00
static __always_inline bool system_uses_lse_atomics(void)
{
arm64: alternatives: add alternative_has_feature_*() Currrently we use a mixture of alternative sequences and static branches to handle features detected at boot time. For ease of maintenance we generally prefer to use static branches in C code, but this has a few downsides: * Each static branch has metadata in the __jump_table section, which is not discarded after features are finalized. This wastes some space, and slows down the patching of other static branches. * The static branches are patched at a different point in time from the alternatives, so changes are not atomic. This leaves a transient period where there could be a mismatch between the behaviour of alternatives and static branches, which could be problematic for some features (e.g. pseudo-NMI). * More (instrumentable) kernel code is executed to patch each static branch, which can be risky when patching certain features (e.g. irqflags management for pseudo-NMI). * When CONFIG_JUMP_LABEL=n, static branches are turned into a load of a flag and a conditional branch. This means it isn't safe to use such static branches in an alternative address space (e.g. the NVHE/PKVM hyp code), where the generated address isn't safe to acccess. To deal with these issues, this patch introduces new alternative_has_feature_*() helpers, which work like static branches but are patched using alternatives. This ensures the patching is performed at the same time as other alternative patching, allows the metadata to be freed after patching, and is safe for use in alternative address spaces. Note that all supported toolchains have asm goto support, and since commit: a0a12c3ed057af57 ("asm goto: eradicate CC_HAS_ASM_GOTO)" ... the CC_HAS_ASM_GOTO Kconfig symbol has been removed, so no feature check is necessary, and we can always make use of asm goto. Additionally, note that: * This has no impact on cpus_have_cap(), which is a dynamic check. * This has no functional impact on cpus_have_const_cap(). The branches are patched slightly later than before this patch, but these branches are not reachable until caps have been finalised. * It is now invalid to use cpus_have_final_cap() in the window between feature detection and patching. All existing uses are only expected after patching anyway, so this should not be a problem. * The LSE atomics will now be enabled during alternatives patching rather than immediately before. As the LL/SC an LSE atomics are functionally equivalent this should not be problematic. When building defconfig with GCC 12.1.0, the resulting Image is 64KiB smaller: | % ls -al Image-* | -rw-r--r-- 1 mark mark 37108224 Aug 23 09:56 Image-after | -rw-r--r-- 1 mark mark 37173760 Aug 23 09:54 Image-before According to bloat-o-meter.pl: | add/remove: 44/34 grow/shrink: 602/1294 up/down: 39692/-61108 (-21416) | Function old new delta | [...] | Total: Before=16618336, After=16596920, chg -0.13% | add/remove: 0/2 grow/shrink: 0/0 up/down: 0/-1296 (-1296) | Data old new delta | arm64_const_caps_ready 16 - -16 | cpu_hwcap_keys 1280 - -1280 | Total: Before=8987120, After=8985824, chg -0.01% | add/remove: 0/0 grow/shrink: 0/0 up/down: 0/0 (0) | RO Data old new delta | Total: Before=18408, After=18408, chg +0.00% Signed-off-by: Mark Rutland <mark.rutland@arm.com> Cc: Ard Biesheuvel <ardb@kernel.org> Cc: James Morse <james.morse@arm.com> Cc: Joey Gouly <joey.gouly@arm.com> Cc: Marc Zyngier <maz@kernel.org> Cc: Will Deacon <will@kernel.org> Reviewed-by: Ard Biesheuvel <ardb@kernel.org> Link: https://lore.kernel.org/r/20220912162210.3626215-8-mark.rutland@arm.com Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2022-09-12 17:22:09 +01:00
return alternative_has_feature_likely(ARM64_HAS_LSE_ATOMICS);
}
#define __lse_ll_sc_body(op, ...) \
({ \
system_uses_lse_atomics() ? \
__lse_##op(__VA_ARGS__) : \
__ll_sc_##op(__VA_ARGS__); \
})
/* In-line patching at runtime */
#define ARM64_LSE_ATOMIC_INSN(llsc, lse) \
ALTERNATIVE(llsc, __LSE_PREAMBLE lse, ARM64_HAS_LSE_ATOMICS)
#else /* CONFIG_ARM64_LSE_ATOMICS */
static inline bool system_uses_lse_atomics(void) { return false; }
#define __lse_ll_sc_body(op, ...) __ll_sc_##op(__VA_ARGS__)
#define ARM64_LSE_ATOMIC_INSN(llsc, lse) llsc
#endif /* CONFIG_ARM64_LSE_ATOMICS */
#endif /* __ASM_LSE_H */