linux-dev/arch/arm/kernel/sleep.S, branch linus/master

ARM: mm: switch to swapper_pg_dir early for vmap'ed stack

2022-01-24T19:37:55Z

When onlining a CPU, switch to swapper_pg_dir as soon as possible so that it is guaranteed that the vmap'ed stack is mapped before it is used. Signed-off-by: Ard Biesheuvel

ARM: percpu: add SMP_ON_UP support

2021-12-06T11:49:17Z

Permit the use of the TPIDRPRW system register for carrying the per-CPU offset in generic SMP configurations that also target non-SMP capable ARMv6 cores. This uses the SMP_ON_UP code patching framework to turn all TPIDRPRW accesses into reads/writes of entry #0 in the __per_cpu_offset array. While at it, switch over some existing direct TPIDRPRW accesses in asm code to invocations of a new helper that is patched in the same way when necessary. Note that CPU_V6+SMP without SMP_ON_UP results in a kernel that does not boot on v6 CPUs without SMP extensions, so add this dependency to Kconfig as well. Acked-by: Linus Walleij Acked-by: Nicolas Pitre Signed-off-by: Ard Biesheuvel Tested-by: Marc Zyngier Tested-by: Vladimir Murzin # ARMv7M

ARM: implement support for vmap'ed stacks

2021-12-03T14:11:33Z

Wire up the generic support for managing task stack allocations via vmalloc, and implement the entry code that detects whether we faulted because of a stack overrun (or future stack overrun caused by pushing the pt_regs array) While this adds a fair amount of tricky entry asm code, it should be noted that it only adds a TST + branch to the svc_entry path. The code implementing the non-trivial handling of the overflow stack is emitted out-of-line into the .text section. Since on ARM, we rely on do_translation_fault() to keep PMD level page table entries that cover the vmalloc region up to date, we need to ensure that we don't hit such a stale PMD entry when accessing the stack. So we do a dummy read from the new stack while still running from the old one on the context switch path, and bump the vmalloc_seq counter when PMD level entries in the vmalloc range are modified, so that the MM switch fetches the latest version of the entries. Note that we need to increase the per-mode stack by 1 word, to gain some space to stash a GPR until we know it is safe to touch the stack. However, due to the cacheline alignment of the struct, this does not actually increase the memory footprint of the struct stack array at all. Signed-off-by: Ard Biesheuvel Tested-by: Keith Packard Tested-by: Marc Zyngier Tested-by: Vladimir Murzin # ARMv7M

ARM: sleep.S: use PC-relative insn sequence for sleep_save_sp/mpidr_hash

2020-10-28T16:05:40Z

Replace the open coded PC relative offset calculations with adr_l and ldr_l invocations. This removes some open coded PC relative arithmetic, avoids literal pools on v7+, and slightly reduces the footprint of the code. Note that ALT_SMP() expects a single instruction so move the macro invocation after it. Reviewed-by: Nicolas Pitre Signed-off-by: Ard Biesheuvel

ARM: 8847/1: pm: fix HYP/SVC mode mismatch when MCPM is used

2019-02-26T11:32:54Z

MCPM does a soft reset of the CPUs and uses common cpu_resume() routine to perform low-level platform initialization. This results in a try to install HYP stubs for the second time for each CPU and results in false HYP/SVC mode mismatch detection. The HYP stubs are already installed at the beginning of the kernel initialization on the boot CPU (head.S) or in the secondary_startup() for other CPUs. To fix this issue MCPM code should use a cpu_resume() routine without HYP stubs installation. This change fixes HYP/SVC mode mismatch on Samsung Exynos5422-based Odroid XU3/XU4/HC1 boards. Fixes: 3721924c8154 ("ARM: 8081/1: MCPM: provide infrastructure to allow for MCPM loopback") Signed-off-by: Marek Szyprowski Acked-by: Nicolas Pitre Tested-by: Anand Moon Signed-off-by: Russell King

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

2017-11-02T10:10:55Z

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: align .data section

2017-08-14T15:22:55Z

Robert Jarzmik reports that his PXA25x system fails to boot with 4.12, failing at __flush_whole_cache in arch/arm/mm/proc-xscale.S:215: 0xc0019e20 <+0>: ldr r1, [pc, #788] 0xc0019e24 <+4>: ldr r0, [r1] <== here with r1 containing 0xc06f82cd, which is the address of "clean_addr". Examination of the System.map shows: c06f22c8 D user_pmd_table c06f22cc d __warned.19178 c06f22cd d clean_addr indicating that a .data.unlikely section has appeared just before the .data section from proc-xscale.S. According to objdump -h, it appears that our assembly files default their .data alignment to 2**0, which is bad news if the preceding .data section size is not power-of-2 aligned at link time. Add the appropriate .align directives to all assembly files in arch/arm that are missing them where we require an appropriate alignment. Reported-by: Robert Jarzmik Tested-by: Robert Jarzmik Signed-off-by: Russell King

ARM: fix new BSYM() usage introduced via for-arm-soc branch

2015-06-12T20:19:35Z

Commit 32e55a777f83 ("ARM: 8389/1: Add cpu_resume_arm() for firmwares that resume in ARM state") needed to introduce a new usage of BSYM() to fix a problem with a previous patch. This in turn causes a conflict with the "bsym" branch which removes this symbol, replacing it with a 'badr' assembly macro. Fix this up. Signed-off-by: Russell King

Merge branch 'for-arm-soc' into for-next

2015-06-12T20:18:59Z

ARM: fix EFM32 build breakage caused by cpu_resume_arm

2015-06-12T20:17:37Z

Fix: arch/arm/kernel/sleep.S:121: Error: selected processor does not support ARM opcodes arch/arm/kernel/sleep.S:123: Error: attempt to use an ARM instruction on a Thumb-only processor -- `adr r9,1f+1' arch/arm/kernel/sleep.S:124: Error: attempt to use an ARM instruction on a Thumb-only processor -- `bx r9' Signed-off-by: Russell King