linux-stable.git/arch/mips, branch v5.4.112

MIPS: Drop 32-bit asm string functions

2021-03-07T11:20:43+00:00

commit 3c0be5849259b729580c23549330973a2dd513a2 upstream.

We have assembly implementations of strcpy(), strncpy(), strcmp() &
strncmp() which:

 - Are simple byte-at-a-time loops with no particular optimizations. As
   a comment in the code describes, they're "rather naive".

 - Offer no clear performance advantage over the generic C
   implementations - in microbenchmarks performed by Alexander Lobakin
   the asm functions sometimes win & sometimes lose, but generally not
   by large margins in either direction.

 - Don't support 64-bit kernels, where we already make use of the
   generic C implementations.

 - Tend to bloat kernel code size due to inlining.

 - Don't support CONFIG_FORTIFY_SOURCE.

 - Won't support nanoMIPS without rework.

For all of these reasons, delete the asm implementations & make use of
the generic C implementations for 32-bit kernels just like we already do
for 64-bit kernels.

Signed-off-by: Paul Burton 
URL: https://lore.kernel.org/linux-mips/a2a35f1cf58d6db19eb4af9b4ae21e35@dlink.ru/
Cc: Alexander Lobakin 
Reviewed-by: Philippe Mathieu-Daudé 
Cc: linux-mips@vger.kernel.org
Signed-off-by: Florian Westphal 
Signed-off-by: Greg Kroah-Hartman

MIPS: VDSO: Use CLANG_FLAGS instead of filtering out '--target='

2021-03-07T11:20:41+00:00

commit 76d7fff22be3e4185ee5f9da2eecbd8188e76b2c upstream.

Commit ee67855ecd9d ("MIPS: vdso: Allow clang's --target flag in VDSO
cflags") allowed the '--target=' flag from the main Makefile to filter
through to the vDSO. However, it did not bring any of the other clang
specific flags for controlling the integrated assembler and the GNU
tools locations (--prefix=, --gcc-toolchain=, and -no-integrated-as).
Without these, we will get a warning (visible with tinyconfig):

arch/mips/vdso/elf.S:14:1: warning: DWARF2 only supports one section per
compilation unit
.pushsection .note.Linux, "a",@note ; .balign 4 ; .long 2f - 1f ; .long
4484f - 3f ; .long 0 ; 1:.asciz "Linux" ; 2:.balign 4 ; 3:
^
arch/mips/vdso/elf.S:34:2: warning: DWARF2 only supports one section per
compilation unit
 .section .mips_abiflags, "a"
 ^

All of these flags are bundled up under CLANG_FLAGS in the main Makefile
and exported so that they can be added to Makefiles that set their own
CFLAGS. Use this value instead of filtering out '--target=' so there is
no warning and all of the tools are properly used.

Cc: stable@vger.kernel.org
Fixes: ee67855ecd9d ("MIPS: vdso: Allow clang's --target flag in VDSO cflags")
Link: https://github.com/ClangBuiltLinux/linux/issues/1256
Reported-by: Anders Roxell 
Signed-off-by: Nathan Chancellor 
Tested-by: Anders Roxell 
Signed-off-by: Thomas Bogendoerfer 
[nc: Fix conflict due to lack of 99570c3da96a in 5.4]
Signed-off-by: Nathan Chancellor 
Signed-off-by: Greg Kroah-Hartman

MIPS: properly stop .eh_frame generation

2021-03-04T09:26:21+00:00

[ Upstream commit 894ef530012fb5078466efdfb2c15d8b2f1565cd ]

Commit 866b6a89c6d1 ("MIPS: Add DWARF unwinding to assembly") added
-fno-asynchronous-unwind-tables to KBUILD_CFLAGS to prevent compiler
from emitting .eh_frame symbols.
However, as MIPS heavily uses CFI, that's not enough. Use the
approach taken for x86 (as it also uses CFI) and explicitly put CFI
symbols into the .debug_frame section (except for VDSO).
This allows us to drop .eh_frame from DISCARDS as it's no longer
being generated.

Fixes: 866b6a89c6d1 ("MIPS: Add DWARF unwinding to assembly")
Suggested-by: Kees Cook 
Signed-off-by: Alexander Lobakin 
Reviewed-by: Kees Cook 
Reviewed-by: Nathan Chancellor 
Signed-off-by: Thomas Bogendoerfer 
Signed-off-by: Sasha Levin

MIPS: lantiq: Explicitly compare LTQ_EBU_PCC_ISTAT against 0

2021-03-04T09:26:20+00:00

[ Upstream commit c6f2a9e17b9bef7677caddb1626c2402f3e9d2bd ]

When building xway_defconfig with clang:

arch/mips/lantiq/irq.c:305:48: error: use of logical '&&' with constant
operand [-Werror,-Wconstant-logical-operand]
        if ((irq == LTQ_ICU_EBU_IRQ) && (module == 0) && LTQ_EBU_PCC_ISTAT)
                                                      ^ ~~~~~~~~~~~~~~~~~
arch/mips/lantiq/irq.c:305:48: note: use '&' for a bitwise operation
        if ((irq == LTQ_ICU_EBU_IRQ) && (module == 0) && LTQ_EBU_PCC_ISTAT)
                                                      ^~
                                                      &
arch/mips/lantiq/irq.c:305:48: note: remove constant to silence this
warning
        if ((irq == LTQ_ICU_EBU_IRQ) && (module == 0) && LTQ_EBU_PCC_ISTAT)
                                                     ~^~~~~~~~~~~~~~~~~~~~
1 error generated.

Explicitly compare the constant LTQ_EBU_PCC_ISTAT against 0 to fix the
warning. Additionally, remove the unnecessary parentheses as this is a
simple conditional statement and shorthand '== 0' to '!'.

Fixes: 3645da0276ae ("OF: MIPS: lantiq: implement irq_domain support")
Link: https://github.com/ClangBuiltLinux/linux/issues/807
Reported-by: Dmitry Golovin 
Signed-off-by: Nathan Chancellor 
Signed-off-by: Thomas Bogendoerfer 
Signed-off-by: Sasha Levin

MIPS: c-r4k: Fix section mismatch for loongson2_sc_init

2021-03-04T09:26:19+00:00

[ Upstream commit c58734eee6a2151ba033c0dcb31902c89e310374 ]

When building with clang, the following section mismatch warning occurs:

WARNING: modpost: vmlinux.o(.text+0x24490): Section mismatch in
reference from the function r4k_cache_init() to the function
.init.text:loongson2_sc_init()

This should have been fixed with commit ad4fddef5f23 ("mips: fix Section
mismatch in reference") but it was missed. Remove the improper __init
annotation like that commit did.

Fixes: 078a55fc824c ("MIPS: Delete __cpuinit/__CPUINIT usage from MIPS code")
Link: https://github.com/ClangBuiltLinux/linux/issues/787
Signed-off-by: Nathan Chancellor 
Reviewed-by: Huacai Chen 
Signed-off-by: Thomas Bogendoerfer 
Signed-off-by: Sasha Levin

MIPS: vmlinux.lds.S: add missing PAGE_ALIGNED_DATA() section

2021-03-04T09:26:10+00:00

commit 8ac7c87acdcac156670f9920c8acbd84308ff4b1 upstream.

MIPS uses its own declaration of rwdata, and thus it should be kept
in sync with the asm-generic one. Currently PAGE_ALIGNED_DATA() is
missing from the linker script, which emits the following ld
warnings:

mips-alpine-linux-musl-ld: warning: orphan section
`.data..page_aligned' from `arch/mips/kernel/vdso.o' being placed
in section `.data..page_aligned'
mips-alpine-linux-musl-ld: warning: orphan section
`.data..page_aligned' from `arch/mips/vdso/vdso-image.o' being placed
in section `.data..page_aligned'

Add the necessary declaration, so the mentioned structures will be
placed in vmlinux as intended:

ffffffff80630580 D __end_once
ffffffff80630580 D __start___dyndbg
ffffffff80630580 D __start_once
ffffffff80630580 D __stop___dyndbg
ffffffff80634000 d mips_vdso_data
ffffffff80638000 d vdso_data
ffffffff80638580 D _gp
ffffffff8063c000 T __init_begin
ffffffff8063c000 D _edata
ffffffff8063c000 T _sinittext

->

ffffffff805a4000 D __end_init_task
ffffffff805a4000 D __nosave_begin
ffffffff805a4000 D __nosave_end
ffffffff805a4000 d mips_vdso_data
ffffffff805a8000 d vdso_data
ffffffff805ac000 D mmlist_lock
ffffffff805ac080 D tasklist_lock

Fixes: ebb5e78cc634 ("MIPS: Initial implementation of a VDSO")
Signed-off-by: Alexander Lobakin 
Reviewed-by: Kees Cook 
Reviewed-by: Nathan Chancellor 
Cc: stable@vger.kernel.org # 4.4+
Signed-off-by: Thomas Bogendoerfer 
Signed-off-by: Greg Kroah-Hartman

MIPS: relocatable: fix possible boot hangup with KASLR enabled

2021-01-19T17:26:12+00:00

commit 69e976831cd53f9ba304fd20305b2025ecc78eab upstream.

LLVM-built Linux triggered a boot hangup with KASLR enabled.

arch/mips/kernel/relocate.c:get_random_boot() uses linux_banner,
which is a string constant, as a random seed, but accesses it
as an array of unsigned long (in rotate_xor()).
When the address of linux_banner is not aligned to sizeof(long),
such access emits unaligned access exception and hangs the kernel.

Use PTR_ALIGN() to align input address to sizeof(long) and also
align down the input length to prevent possible access-beyond-end.

Fixes: 405bc8fd12f5 ("MIPS: Kernel: Implement KASLR using CONFIG_RELOCATABLE")
Cc: stable@vger.kernel.org # 4.7+
Signed-off-by: Alexander Lobakin 
Tested-by: Nathan Chancellor 
Reviewed-by: Kees Cook 
Signed-off-by: Thomas Bogendoerfer 
Signed-off-by: Greg Kroah-Hartman

MIPS: boot: Fix unaligned access with CONFIG_MIPS_RAW_APPENDED_DTB

2021-01-19T17:26:12+00:00

commit 4d4f9c1a17a3480f8fe523673f7232b254d724b7 upstream.

The compressed payload is not necesarily 4-byte aligned, at least when
compiling with Clang. In that case, the 4-byte value appended to the
compressed payload that corresponds to the uncompressed kernel image
size must be read using get_unaligned_le32().

This fixes Clang-built kernels not booting on MIPS (tested on a Ingenic
JZ4770 board).

Fixes: b8f54f2cde78 ("MIPS: ZBOOT: copy appended dtb to the end of the kernel")
Cc:  # v4.7
Signed-off-by: Paul Cercueil 
Reviewed-by: Nick Desaulniers 
Reviewed-by: Philippe Mathieu-Daudé 
Signed-off-by: Thomas Bogendoerfer 
Signed-off-by: Greg Kroah-Hartman

mips: lib: uncached: fix non-standard usage of variable 'sp'

2021-01-19T17:26:12+00:00

commit 5b058973d3205578aa6c9a71392e072a11ca44ef upstream.

When building mips tinyconfig with clang the following warning show up:

arch/mips/lib/uncached.c:45:6: warning: variable 'sp' is uninitialized when used here [-Wuninitialized]
        if (sp >= (long)CKSEG0 && sp < (long)CKSEG2)
            ^~
arch/mips/lib/uncached.c:40:18: note: initialize the variable 'sp' to silence this warning
        register long sp __asm__("$sp");
                        ^
                         = 0
1 warning generated.

Rework to make an explicit inline move, instead of the non-standard use
of specifying registers for local variables. This is what's written
from the gcc-10 manual [1] about specifying registers for local
variables:

"6.47.5.2 Specifying Registers for Local Variables
.................................................
[...]

"The only supported use for this feature is to specify registers for
input and output operands when calling Extended 'asm' (*note Extended
Asm::).  [...]".

[1] https://docs.w3cub.com/gcc~10/local-register-variables
Signed-off-by: Anders Roxell 
Reported-by: Nathan Chancellor 
Reported-by: Naresh Kamboju 
Reviewed-by: Nick Desaulniers 
Signed-off-by: Thomas Bogendoerfer 
Signed-off-by: Greg Kroah-Hartman

mips: fix Section mismatch in reference

2021-01-19T17:26:12+00:00

commit ad4fddef5f2345aa9214e979febe2f47639c10d9 upstream.

When building mips tinyconfig with clang the following error show up:

WARNING: modpost: vmlinux.o(.text+0x1940c): Section mismatch in reference from the function r4k_cache_init() to the function .init.text:loongson3_sc_init()
The function r4k_cache_init() references
the function __init loongson3_sc_init().
This is often because r4k_cache_init lacks a __init
annotation or the annotation of loongson3_sc_init is wrong.

Remove marked __init from function loongson3_sc_init(),
mips_sc_probe_cm3(), and mips_sc_probe().

Signed-off-by: Anders Roxell 
Reviewed-by: Nick Desaulniers 
Signed-off-by: Thomas Bogendoerfer 
Signed-off-by: Greg Kroah-Hartman