linux-stable.git/arch/mips/fw/lib, branch master

MIPS: Fix big-endian stack argument fetching in o32 wrapper

2026-05-26T14:35:36+00:00

Fix an issue in call_o32() where the upper 32-bit half of incoming n64
stack arguments is fetched and used for outgoing o32 stack arguments on
big-endian platforms.

This code was adapted from arch/mips/dec/prom/call_o32.S which was meant
for a little-endian platform only and therefore using 32-bit loads from
64-bit stack slot locations holding incoming stack arguments resulted in
correct values being retrieved for data that is expected to be 32-bit.

This works on little-endian platforms where the lower 32-bit half of the
64-bit value is located at every 64-bit stack slot location.  However on
big-endian platforms the lower 32-bit half is instead located at offset
4 from every 64-bit stack slot location.

So to fix the issue the offset of 4 would have to be used on big-endian
platforms only, or alternatively a 64-bit load from the 64-bit stack
slot location can be used across the board, as the subsequent 32-bit
store to the corresponding outgoing stack argument slot will correctly
truncate the value and cause no unpredictable result.  We already take
advantage of this architectural feature for the incoming arguments held
in $a6 and $a7 registers, since the o32 wrapper does not know how many
incoming arguments there are and consequently propagates incoming data
which may not be 32-bit.

Since this code is generally supposed to be used with the stack located
in cached memory there is no extra overhead expected for 64-bit loads as
opposed to 32-bit ones, so pick this variant for code simplicity.

Fixes: 231a35d37293 ("[MIPS] RM: Collected changes")
Signed-off-by: Maciej W. Rozycki 
Signed-off-by: Thomas Bogendoerfer

MIPS: fw: Allow firmware to pass a empty env

2023-04-12T13:07:36+00:00

fw_getenv will use env entry to determine style of env,
however it is legal for firmware to just pass a empty list.

Check if first entry exist before running strchr to avoid
null pointer dereference.

Cc: stable@vger.kernel.org
Link: https://github.com/clbr/n64bootloader/issues/5
Signed-off-by: Jiaxun Yang 
Signed-off-by: Thomas Bogendoerfer

MIPS: do not compile generic functions for CONFIG_CAVIUM_OCTEON_SOC

2020-03-25T15:07:13+00:00

MIPS provides multiple definitions for the following functions:

  fw_init_cmdline
  __delay
  __udelay
  __ndelay
  memmove
  __rmemcpy
  memcpy
  __copy_user

The generic ones are defined in lib-y objects, which are overridden by
the Octeon ones when CONFIG_CAVIUM_OCTEON_SOC is enabled.

The use of EXPORT_SYMBOL in static libraries potentially causes a
problem for the llvm linker [1]. So, I want to forcibly link lib-y
objects to vmlinux when CONFIG_MODULES=y.

As a groundwork, we must fix multiple definitions that have previously
been hidden by lib-y.

If you look at lib/string.c, arch can define __HAVE_ARCH_* to opt out
the generic implementation.

Similarly, this commit adds CONFIG_HAVE_PLAT_* to allow a platform
to opt out the MIPS generic code.

[1]: https://github.com/ClangBuiltLinux/linux/issues/515

Reported-by: kbuild test robot 
Signed-off-by: Masahiro Yamada 
Signed-off-by: Thomas Bogendoerfer

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152

2019-05-30T18:26:32+00:00

Based on 1 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license as published by
  the free software foundation either version 2 of the license or at
  your option any later version

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 3029 file(s).

Signed-off-by: Thomas Gleixner 
Reviewed-by: Allison Randal 
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de
Signed-off-by: Greg Kroah-Hartman

treewide: Add SPDX license identifier - Makefile/Kconfig

2019-05-21T08:50:46+00:00

Add SPDX license identifiers to all Make/Kconfig files which:

 - Have no license information of any form

These files fall under the project license, GPL v2 only. The resulting SPDX
license identifier is:

  GPL-2.0-only

Signed-off-by: Thomas Gleixner 
Signed-off-by: Greg Kroah-Hartman

MIPS: FW: Use kstrtoul() to parse unsigned long from the fw environment

2014-11-24T06:45:26+00:00

Fix some value corruptions with values that can't be represented in a
signed long.

Signed-off-by: Alban Bedel 
Cc: linux-kernel@vger.kernel.org
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/8358/
Signed-off-by: Ralf Baechle

MIPS: FW: Fix parsing u-boot environment

2014-11-24T06:45:25+00:00

When reading u-boot's key=value pairs it should skip the '=' and not
use the next argument.

Signed-off-by: Alban Bedel 
Cc: linux-kernel@vger.kernel.org
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/8357/
Signed-off-by: Ralf Baechle

MIPS: DEC/SNI: O32 wrapper stack switching fixes

2014-05-12T22:29:35+00:00

Commit 231a35d37293ab88d325a9cb94e5474c156282c0 [[MIPS] RM: Collected
changes] broke DECstation support by introducing an incompatible copy of
arch/mips/dec/prom/call_o32.S in arch/mips/fw/lib/, built unconditionally.
The copy happens to land earlier of the two among the modules used in the
link and is therefore chosen for the DECstation rather than the intended
original.  As a result random kernel data is corrupted because a pointer
to the "%s" formatted output template is used as a temporary stack pointer
rather than being passed down to prom_printf.  This also explains why
prom_printf still works, up to a point -- the next argument is the actual
string to output so it works just fine as the output template until enough
kernel data has been corrupted to cause a crash.

This change adjusts the modified wrapper in arch/mips/fw/lib/call_o32.S to
let callers request no stack switching by passing a null temporary stack
pointer in $a1, reworks the DECstation callers to work with the updated
interface and removes the old copy from arch/mips/dec/prom/call_o32.S.  A
few minor readability adjustments are included as well, most importantly
O32_SZREG is now used throughout where applicable rather than hardcoded
multiplies of 4 and $fp is used to access the argument save area as a more
usual register to operate the stack with rather than $s0.

Finally an update is made to the temporary stack space used by the SNI
platform to guarantee 8-byte alignment as per o32 requirements.

Signed-off-by: Maciej W. Rozycki 
Cc: Thomas Bogendoerfer 
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6668/
Signed-off-by: Ralf Baechle

MIPS: FW: Add environment variable processing.

2013-05-08T10:30:09+00:00

Add parsing of the environment and command line variables passed to
the kernel to the firmware library.

Signed-off-by: Steven J. Hill

MIPS: Whitespace cleanup.

2013-02-01T09:00:22+00:00

Having received another series of whitespace patches I decided to do this
once and for all rather than dealing with this kind of patches trickling
in forever.

Signed-off-by: Ralf Baechle