linux-toradex.git/arch/mips/kernel/ftrace.c, branch v6.7

MIPS: kernel: Remove not needed set_fs calls

2021-04-06T12:36:56+00:00

flush_icache_range always does flush kernel address ranges, so no
need to do the set_fs dance.

Signed-off-by: Thomas Bogendoerfer 
Reviewed-by: Christoph Hellwig

Revert "MIPS: kernel: {ftrace,kgdb}: Set correct address limit for cache flushes"

2021-02-13T08:53:08+00:00

This reverts commit 6ebda44f366478d1eea180d93154e7d97b591f50.

All icache flushes in this code paths are done via flush_icache_range(),
which only uses normal cache instruction. And this is the correct thing
for EVA mode, too. So no need to do set_fs(KERNEL_DS) here.

Signed-off-by: Thomas Bogendoerfer 
Reviewed-by: Christoph Hellwig

MIPS: ftrace: Remove redundant #ifdef CONFIG_DYNAMIC_FTRACE

2020-08-17T11:00:24+00:00

There exists redundant #ifdef CONFIG_DYNAMIC_FTRACE in ftrace.c, remove it.

Signed-off-by: Zejiang Tang 
Reviewed-by: Steven Rostedt (VMware) 
Signed-off-by: Thomas Bogendoerfer

MIPS: ftrace: Reword prepare_ftrace_return() comment block

2019-06-11T22:46:21+00:00

Improve the comment block for prepare_ftrace_return().

Signed-off-by: Geert Uytterhoeven 
Signed-off-by: Paul Burton 
Cc: Ralf Baechle 
Cc: James Hogan 
Cc: Steven Rostedt 
Cc: Ingo Molnar 
Cc: linux-mips@vger.kernel.org
Cc: linux-kernel@vger.kernel.org

get rid of legacy 'get_ds()' function

2019-03-04T18:50:14+00:00

Every in-kernel use of this function defined it to KERNEL_DS (either as
an actual define, or as an inline function).  It's an entirely
historical artifact, and long long long ago used to actually read the
segment selector valueof '%ds' on x86.

Which in the kernel is always KERNEL_DS.

Inspired by a patch from Jann Horn that just did this for a very small
subset of users (the ones in fs/), along with Al who suggested a script.
I then just took it to the logical extreme and removed all the remaining
gunk.

Roughly scripted with

   git grep -l '(get_ds())' -- :^tools/ | xargs sed -i 's/(get_ds())/(KERNEL_DS)/'
   git grep -lw 'get_ds' -- :^tools/ | xargs sed -i '/^#define get_ds()/d'

plus manual fixups to remove a few unusual usage patterns, the couple of
inline function cases and to fix up a comment that had become stale.

The 'get_ds()' function remains in an x86 kvm selftest, since in user
space it actually does something relevant.

Inspired-by: Jann Horn 
Inspired-by: Al Viro 
Signed-off-by: Linus Torvalds

Merge tag 'mips_4.21' of git://git.kernel.org/pub/scm/linux/kernel/git/mips/linux

2018-12-26T18:45:33+00:00

Pull MIPS updates from Paul Burton:
 "Here's the main MIPS pull for Linux 4.21. Core architecture changes
  include:

   - Syscall tables & definitions for unistd.h are now generated by
     scripts, providing greater consistency with other architectures &
     making it easier to add new syscalls.

   - Support for building kernels with no floating point support, upon
     which any userland attempting to use floating point instructions
     will receive a SIGILL. Mostly useful to shrink the kernel & as
     preparation for nanoMIPS support which does not yet include FP.

   - MIPS SIMD Architecture (MSA) vector register context is now exposed
     by ptrace via a new NT_MIPS_MSA regset.

   - ASIDs are now stored as 64b values even for MIPS32 kernels,
     expanding the ASID version field sufficiently that we don't need to
     worry about overflow & avoiding rare issues with reused ASIDs that
     have been observed in the wild.

   - The branch delay slot "emulation" page is now mapped without write
     permission for the user, preventing its use as a nice location for
     attacks to execute malicious code from.

   - Support for ioremap_prot(), primarily to allow gdb or other ptrace
     users the ability to view their tracee's memory using the same
     cache coherency attribute.

   - Optimizations to more cpu_has_* macros, allowing more to be
     compile-time constant where possible.

   - Enable building the whole kernel with UBSAN instrumentation.

   - Enable building the kernel with link-time dead code & data
     elimination.

  Platform specific changes include:

   - The Boston board gains a workaround for DMA prefetching issues with
     the EG20T Platform Controller Hub that it uses.

   - Cleanups to Cavium Octeon code removing about 20k lines of
     redundant code, mostly unused or duplicate register definitions in
     headers.

   - defconfig updates for the DECstation machines, including new
     defconfigs for r4k & 64b machines.

   - Further work on Loongson 3 support.

   - DMA fixes for SiByte machines"

* tag 'mips_4.21' of git://git.kernel.org/pub/scm/linux/kernel/git/mips/linux: (95 commits)
  MIPS: math-emu: Write-protect delay slot emulation pages
  MIPS: Remove struct mm_context_t fp_mode_switching field
  mips: generate uapi header and system call table files
  mips: add system call table generation support
  mips: remove syscall table entries
  mips: add +1 to __NR_syscalls in uapi header
  mips: rename scall64-64.S to scall64-n64.S
  mips: remove unused macros
  mips: add __NR_syscalls along with __NR_Linux_syscalls
  MIPS: Expand MIPS32 ASIDs to 64 bits
  MIPS: OCTEON: delete redundant register definitions
  MIPS: OCTEON: cvmx_gmxx_inf_mode: use oldest forward compatible definition
  MIPS: OCTEON: cvmx_mio_fus_dat3: use oldest forward compatible definition
  MIPS: OCTEON: cvmx_pko_mem_debug8: use oldest forward compatible definition
  MIPS: OCTEON: octeon-usb: use common gpio_bit definition
  MIPS: OCTEON: enable all OCTEON drivers in defconfig
  mips: annotate implicit fall throughs
  MIPS: Hardcode cpu_has_mips* where target ISA allows
  MIPS: MT: Remove norps command line parameter
  MIPS: Only include mmzone.h when CONFIG_NEED_MULTIPLE_NODES=y
  ...

mips: add +1 to __NR_syscalls in uapi header

2018-12-14T19:19:01+00:00

All other architectures are hold a value for __NR_syscalls will
be equal to the last system call number +1.

But in mips architecture, __NR_syscalls hold the value equal to
total number of system exits in the architecture. One of the
patch in this patch series will genarate uapi header files.

In order to make the implementation common across all architect-
ures, add +1 to __NR_syscalls, which will be equal to the last
system call number +1.

Signed-off-by: Firoz Khan 
Signed-off-by: Paul Burton 
Cc: linux-mips@vger.kernel.org
Cc: Ralf Baechle 
Cc: James Hogan 
Cc: Greg Kroah-Hartman 
Cc: Philippe Ombredanne 
Cc: Thomas Gleixner 
Cc: Kate Stewart 
Cc: y2038@lists.linaro.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-arch@vger.kernel.org
Cc: arnd@arndb.de
Cc: deepa.kernel@gmail.com
Cc: marcin.juszkiewicz@linaro.org

MIPS: function_graph: Simplify with function_graph_enter()

2018-11-28T01:30:36+00:00

The function_graph_enter() function does the work of calling the function
graph hook function and the management of the shadow stack, simplifying the
work done in the architecture dependent prepare_ftrace_return().

Have MIPS use the new code, and remove the shadow stack management as well as
having to set up the trace structure.

This is needed to prepare for a fix of a design bug on how the curr_ret_stack
is used.

Cc: Ralf Baechle 
Cc: Paul Burton 
Cc: James Hogan 
Cc: linux-mips@linux-mips.org
Cc: stable@kernel.org
Fixes: 03274a3ffb449 ("tracing/fgraph: Adjust fgraph depth before calling trace return callback")
Reviewed-by: Masami Hiramatsu 
Signed-off-by: Steven Rostedt (VMware)

MIPS: ftrace: Remove pointer comparison to 0 in prepare_ftrace_return

2018-01-18T21:59:24+00:00

Replace pointer comparison to 0 with NULL in prepare_ftrace_return
to improve code readability. Identified with coccinelle script
'badzero.cocci'.

Signed-off-by: Mathieu Malaterre 
Reviewed-by: James Hogan 
Cc: Ralf Baechle 
Cc: Steven Rostedt 
Cc: Ingo Molnar 
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/18494/
Signed-off-by: James Hogan

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