kernel/linux.git/arch/mips/include/asm/thread_info.h, branch v6.6.132

MIPS: Only use current_stack_pointer on GCC

2022-03-14T14:02:53+00:00

Unfortunately, Clang did not have support for "sp" as a global register definition, and was crashing after the addition of current_stack_pointer. This has been fixed in Clang 14, but earlier Clang versions need to avoid this code, so add a versioned test and revert back to the open-coded asm instances. Fixes Clang build error: fatal error: error in backend: Invalid register name global variable Fixes: 200ed341b864 ("mips: Implement "current_stack_pointer"") Reported-by: Nathan Chancellor Reviewed-by: Nathan Chancellor Link: https://lore.kernel.org/lkml/YikTQRql+il3HbrK@dev-arch.thelio-3990X Cc: Thomas Bogendoerfer Cc: Marc Zyngier Cc: Guenter Roeck Cc: Yanteng Si Cc: linux-mips@vger.kernel.org Signed-off-by: Kees Cook Reviewed-by: Nick Desaulniers Signed-off-by: Thomas Bogendoerfer

mips: Implement "current_stack_pointer"

2022-03-01T15:57:55+00:00

To follow the existing per-arch conventions replace open-coded uses of asm "sp" as "current_stack_pointer". This will let it be used in non-arch places (like HARDENED_USERCOPY). Cc: Thomas Bogendoerfer Cc: Marc Zyngier Cc: Guenter Roeck Cc: Mark Rutland Cc: Yanteng Si Cc: linux-mips@vger.kernel.org Signed-off-by: Kees Cook Signed-off-by: Thomas Bogendoerfer

MIPS: Remove get_fs/set_fs

2021-04-06T13:12:58+00:00

All get_fs/set_fs calls in MIPS code are gone, so remove implementation of it. With the clear separation of user/kernel space access we no longer need the EVA special handling, so get rid of that, too. Signed-off-by: Thomas Bogendoerfer Reviewed-by: Christoph Hellwig

mips: add support for TIF_NOTIFY_SIGNAL

2020-11-09T15:16:55+00:00

Wire up TIF_NOTIFY_SIGNAL handling for mips. Cc: linux-mips@vger.kernel.org Acked-By: Thomas Bogendoerfer Signed-off-by: Jens Axboe

MIPS: Avoid VDSO ABI breakage due to global register variable

2020-01-03T00:41:16+00:00

Declaring __current_thread_info as a global register variable has the effect of preventing GCC from saving & restoring its value in cases where the ABI would typically do so. To quote GCC documentation: > If the register is a call-saved register, call ABI is affected: the > register will not be restored in function epilogue sequences after the > variable has been assigned. Therefore, functions cannot safely return > to callers that assume standard ABI. When our position independent VDSO is built for the n32 or n64 ABIs all functions it exposes should be preserving the value of $gp/$28 for their caller, but in the presence of the __current_thread_info global register variable GCC stops doing so & simply clobbers $gp/$28 when calculating the address of the GOT. In cases where the VDSO returns success this problem will typically be masked by the caller in libc returning & restoring $gp/$28 itself, but that is by no means guaranteed. In cases where the VDSO returns an error libc will typically contain a fallback path which will now fail (typically with a bad memory access) if it attempts anything which relies upon the value of $gp/$28 - eg. accessing anything via the GOT. One fix for this would be to move the declaration of __current_thread_info inside the current_thread_info() function, demoting it from global register variable to local register variable & avoiding inadvertently creating a non-standard calling ABI for the VDSO. Unfortunately this causes issues for clang, which doesn't support local register variables as pointed out by commit fe92da0f355e ("MIPS: Changed current_thread_info() to an equivalent supported by both clang and GCC") which introduced the global register variable before we had a VDSO to worry about. Instead, fix this by continuing to use the global register variable for the kernel proper but declare __current_thread_info as a simple extern variable when building the VDSO. It should never be referenced, and will cause a link error if it is. This resolves the calling convention issue for the VDSO without having any impact upon the build of the kernel itself for either clang or gcc. Signed-off-by: Paul Burton Fixes: ebb5e78cc634 ("MIPS: Initial implementation of a VDSO") Reported-by: Jason A. Donenfeld Reviewed-by: Jason A. Donenfeld Tested-by: Jason A. Donenfeld Cc: Arnd Bergmann Cc: Christian Brauner Cc: Vincenzo Frascino Cc: # v4.4+ Cc: linux-mips@vger.kernel.org Cc: linux-kernel@vger.kernel.org

Construct init thread stack in the linker script rather than by union

2018-01-09T23:21:02+00:00

Construct the init thread stack in the linker script rather than doing it by means of a union so that ia64's init_task.c can be got rid of. The following symbols are then made available from INIT_TASK_DATA() linker script macro: init_thread_union init_stack INIT_TASK_DATA() also expands the region to THREAD_SIZE to accommodate the size of the init stack. init_thread_union is given its own section so that it can be placed into the stack space in the right order. I'm assuming that the ia64 ordering is correct and that the task_struct is first and the thread_info second. Signed-off-by: David Howells Tested-by: Tony Luck Tested-by: Will Deacon (arm64) Tested-by: Palmer Dabbelt Acked-by: Thomas Gleixner

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

MIPS: Remove r2_emul_return from struct thread_info

2017-01-03T15:34:41+00:00

The r2_emul_return field in struct thread_info was used in order to take an alternate codepath when returning to userland, which (besides not implementing certain features) effectively used the eretnc instruction in place of eret. The difference is that eretnc doesn't clear LLBit, and therefore doesn't cause a linked load & store sequence to fail due to emulation like eret would. The reason eret would usually be used to clear LLBit is so that after context switching we ensure that a load performed by one task doesn't influence another task. However commit 7c151d3d5d7a ("MIPS: Make use of the ERETNC instruction on MIPS R6") which introduced the r2_emul_return field and conditional use of eretnc also for some reason began explicitly clearing LLBit during context switches - despite retaining the use of eret for everything but returns from the pre-r6 instruction emulation code. As LLBit is cleared upon context switches anyway, simplify this by using eretnc unconditionally for MIPSr6 kernels. This allows us to remove the 4 byte r2_emul_return boolean from struct thread_info, simplify the return to user code in entry.S and avoid the overhead of tracking & checking state which we don't need. Signed-off-by: Paul Burton Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/14408/ Signed-off-by: Ralf Baechle

MIPS: Add uprobes support.

2015-09-03T10:08:05+00:00

Signed-off-by: Ralf Baechle

Merge branch 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus

2015-04-17T19:50:54+00:00

Pull MIPS updates from Ralf Baechle: "This is the main pull request for MIPS for Linux 4.1. Most noteworthy: - Add more Octeon-optimized crypto functions - Octeon crypto preemption and locking fixes - Little endian support for Octeon - Use correct CSR to soft reset Octeons - Support LEDs on the Octeon-based DSR-1000N - Fix PCI interrupt mapping for the Octeon-based DSR-1000N - Mark prom_free_prom_memory() as __init for a number of systems - Support for Imagination's Pistachio SOC. This includes arch and CLK bits. I'd like to merge pinctrl bits later - Improve parallelism of csum_partial for certain pipelines - Organize DTB files in subdirs like other architectures - Implement read_sched_clock for all MIPS platforms other than Octeon - Massive series of 38 fixes and cleanups for the FPU emulator / kernel - Further FPU remulator work to support new features. This sits on a separate branch which also has been pulled into the 4.1 KVM branch - Clean up and fixes for the SEAD3 eval board; remove unused file - Various updates for Netlogic platforms - A number of small updates for Loongson 3 platforms - Increase the memory limit for ATH79 platforms to 256MB - A fair number of fixes and updates for BCM47xx platforms - Finish the implementation of XPA support - MIPS FDC support. No, not floppy controller but Fast Debug Channel :) - Detect the R16000 used in SGI legacy platforms - Fix Kconfig dependencies for the SSB bus support" * 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus: (265 commits) MIPS: Makefile: Fix MIPS ASE detection code MIPS: asm: elf: Set O32 default FPU flags MIPS: BCM47XX: Fix detecting Microsoft MN-700 & Asus WL500G MIPS: Kconfig: Disable SMP/CPS for 64-bit MIPS: Hibernate: flush TLB entries earlier MIPS: smp-cps: cpu_set FPU mask if FPU present MIPS: lose_fpu(): Disable FPU when MSA enabled MIPS: ralink: add missing symbol for RALINK_ILL_ACC MIPS: ralink: Fix bad config symbol in PCI makefile. SSB: fix Kconfig dependencies MIPS: Malta: Detect and fix bad memsize values Revert "MIPS: Avoid pipeline stalls on some MIPS32R2 cores." MIPS: Octeon: Delete override of cpu_has_mips_r2_exec_hazard. MIPS: Fix cpu_has_mips_r2_exec_hazard. MIPS: kernel: entry.S: Set correct ISA level for mips_ihb MIPS: asm: spinlock: Fix addiu instruction for R10000_LLSC_WAR case MIPS: r4kcache: Use correct base register for MIPS R6 cache flushes MIPS: Kconfig: Fix typo for the r2-to-r6 emulator kernel parameter MIPS: unaligned: Fix regular load/store instruction emulation for EVA MIPS: unaligned: Surround load/store macros in do {} while statements ...