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  1. 22 May, 2020 4 commits
    • Serge Semin's avatar
      mips: Add CP0 Write Merge config support · 742318ad
      Serge Semin authored 
      CP0 config register may indicate whether write-through merging
is allowed. Currently there are two types of the merging available:
SysAD Valid and Full modes. Whether each of them are supported by
the core is implementation dependent. Moreover whether the ability
to change the mode also depends on the chip family instance. Taking
into account all of this we created a dedicated mm_config() method
to detect and enable merging if it's supported. It is called for
MIPS-type processors at CPU-probe stage and attempts to detect whether
the write merging is available. If it's known to be supported and
switchable, then switch on the full mode. Otherwise just perform the
CP0.Config.MM field analysis.

In addition there are platforms like InterAptiv/ProAptiv, which do have
the MM bit field set by default, but having write-through cacheing
unsupported makes write-merging also unsupported. In this case we just
ignore the MM field value.
Co-developed-by: default avatarAlexey Malahov <Alexey.Malahov@baikalelectronics.ru>
Signed-off-by: default avatarAlexey Malahov <Alexey.Malahov@baikalelectronics.ru>
Signed-off-by: default avatarSerge Semin <Sergey.Semin@baikalelectronics.ru>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Paul Burton <paulburton@kernel.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: devicetree@vger.kernel.org
Signed-off-by: default avatarThomas Bogendoerfer <tsbogend@alpha.franken.de>
      742318ad
    • Serge Semin's avatar
      mips: Fix cpu_has_mips64r1/2 activation for MIPS32 CPUs · a2ac81c6
      Serge Semin authored 
      Commit 1aeba347 ("MIPS: Hardcode cpu_has_mips* where target ISA
allows") updated the cpu_has_mips* macro to be replaced with a constant
expression where it's possible. By mistake it wasn't done correctly
for cpu_has_mips64r1/cpu_has_mips64r2 macro. They are defined to
be replaced with conditional expression __isa_range_or_flag(), which
means either ISA revision being within the range or the corresponding
CPU options flag was set at the probe stage or both being true at the
same time. But the ISA level value doesn't indicate whether the ISA is
MIPS32 or MIPS64. Due to this if we select MIPS32r1 - MIPS32r5
architectures the __isa_range() macro will activate the
cpu_has_mips64rX flags, which is incorrect. In order to fix the
problem we make sure the 64bits CPU support is enabled by means of
checking the flag cpu_has_64bits aside with proper ISA range and specific
Revision flag being set.

Fixes: 1aeba347 ("MIPS: Hardcode cpu_has_mips* where target ISA allows")
Signed-off-by: default avatarSerge Semin <Sergey.Semin@baikalelectronics.ru>
Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Paul Burton <paulburton@kernel.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: devicetree@vger.kernel.org
Signed-off-by: default avatarThomas Bogendoerfer <tsbogend@alpha.franken.de>
      a2ac81c6
    • Serge Semin's avatar
      mips: Add MIPS Warrior P5600 support · 281e3aea
      Serge Semin authored 
      This is a MIPS32 Release 5 based IP core with XPA, EVA, dual/quad issue
exec pipes, MMU with two-levels TLB, UCA, MSA, MDU core level features
and system level features like up to six P5600 calculation cores, CM2
with L2 cache, IOCU/IOMMU (though might be unused depending on the
system-specific IP core configuration), GIC, CPC, virtualisation module,
eJTAG and PDtrace.

As being MIPS32 Release 5 based core it provides all the features
available by the CPU_MIPS32_R5 config, while adding a few more like
UCA attribute support, availability of CPU-freq (by means of L2/CM
clock ratio setting), EI/VI GIC modes detection at runtime.

In addition to this if P5600 architecture is enabled modern GNU GCC
provides a specific tuning for P5600 processors with respect to the
classic MIPS32 Release 5. First of all branch-likely avoidance is
activated only when the code is compiled with the speed optimization
(avoidance is always enabled for the pure MIPS32 Release 5
architecture). Secondly the madd/msub avoidance is enabled since
madd/msub utilization isn't profitable due to overhead of getting the
result out of the HI/LO registers. Multiply-accumulate instructions are
activated and utilized together with the necessary code reorder when
multiply-add/multiply-subtract statements are met. Finally load/store
bonding is activated by default. All of these optimizations may make
the code relatively faster than if just MIP32 release 5 architecture
was requested.
Co-developed-by: default avatarAlexey Malahov <Alexey.Malahov@baikalelectronics.ru>
Signed-off-by: default avatarAlexey Malahov <Alexey.Malahov@baikalelectronics.ru>
Signed-off-by: default avatarSerge Semin <Sergey.Semin@baikalelectronics.ru>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Paul Burton <paulburton@kernel.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: devicetree@vger.kernel.org
Signed-off-by: default avatarThomas Bogendoerfer <tsbogend@alpha.franken.de>
      281e3aea
    • Serge Semin's avatar
      mips: Add MIPS Release 5 support · ab7c01fd
      Serge Semin authored 
      There are five MIPS32/64 architecture releases currently available:
from 1 to 6 except fourth one, which was intentionally skipped.
Three of them can be called as major: 1st, 2nd and 6th, that not only
have some system level alterations, but also introduced significant
core/ISA level updates. The rest of the MIPS architecture releases are
minor.

Even though they don't have as much ISA/system/core level changes
as the major ones with respect to the previous releases, they still
provide a set of updates (I'd say they were intended to be the
intermediate releases before a major one) that might be useful for the
kernel and user-level code, when activated by the kernel or compiler.
In particular the following features were introduced or ended up being
available at/after MIPS32/64 Release 5 architecture:
+ the last release of the misaligned memory access instructions,
+ virtualisation - VZ ASE - is optional component of the arch,
+ SIMD - MSA ASE - is optional component of the arch,
+ DSP ASE is optional component of the arch,
+ CP0.Status.FR=1 for CP1.FIR.F64=1 (pure 64-bit FPU general registers)
  must be available if FPU is implemented,
+ CP1.FIR.Has2008 support is required so CP1.FCSR.{ABS2008,NAN2008} bits
  are available.
+ UFR/UNFR aliases to access CP0.Status.FR from user-space by means of
  ctc1/cfc1 instructions (enabled by CP0.Config5.UFR),
+ CP0.COnfig5.LLB=1 and eretnc instruction are implemented to without
  accidentally clearing LL-bit when returning from an interrupt,
  exception, or error trap,
+ XPA feature together with extended versions of CPx registers is
  introduced, which needs to have mfhc0/mthc0 instructions available.

So due to these changes GNU GCC provides an extended instructions set
support for MIPS32/64 Release 5 by default like eretnc/mfhc0/mthc0. Even
though the architecture alteration isn't that big, it still worth to be
taken into account by the kernel software. Finally we can't deny that
some optimization/limitations might be found in future and implemented
on some level in kernel or compiler. In this case having even
intermediate MIPS architecture releases support would be more than
useful.

So the most of the changes provided by this commit can be split into
either compile- or runtime configs related. The compile-time related
changes are caused by adding the new CONFIG_CPU_MIPS32_R5/CONFIG_CPU_MIPSR5
configs and concern the code activating MIPSR2 or MIPSR6 already
implemented features (like eretnc/LLbit, mthc0/mfhc0). In addition
CPU_HAS_MSA can be now freely enabled for MIPS32/64 release 5 based
platforms as this is done for CPU_MIPS32_R6 CPUs. The runtime changes
concerns the features which are handled with respect to the MIPS ISA
revision detected at run-time by means of CP0.Config.{AT,AR} bits. Alas
these fields can be used to detect either r1 or r2 or r6 releases.
But since we know which CPUs in fact support the R5 arch, we can manually
set MIPS_CPU_ISA_M32R5/MIPS_CPU_ISA_M64R5 bit of c->isa_level and then
use cpu_has_mips32r5/cpu_has_mips64r5 where it's appropriate.

Since XPA/EVA provide too complex alterationss and to have them used with
MIPS32 Release 2 charged kernels (for compatibility with current platform
configs) they are left to be setup as a separate kernel configs.
Co-developed-by: default avatarAlexey Malahov <Alexey.Malahov@baikalelectronics.ru>
Signed-off-by: default avatarAlexey Malahov <Alexey.Malahov@baikalelectronics.ru>
Signed-off-by: default avatarSerge Semin <Sergey.Semin@baikalelectronics.ru>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Paul Burton <paulburton@kernel.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: devicetree@vger.kernel.org
Signed-off-by: default avatarThomas Bogendoerfer <tsbogend@alpha.franken.de>
      ab7c01fd
  3. 21 May, 2020 2 commits
  5. 20 May, 2020 2 commits
  7. 19 May, 2020 3 commits
  9. 18 May, 2020 2 commits
  11. 17 May, 2020 6 commits
  13. 15 May, 2020 5 commits
  15. 13 May, 2020 7 commits
  17. 12 May, 2020 6 commits
    • Thomas Bogendoerfer's avatar
      MIPS: Only include the platform file needed · 26bff9eb
      Thomas Bogendoerfer authored 
      Instead of including all Platform files, we simply include the
needed one and avoid clashes with makefile variables.
Signed-off-by: default avatarThomas Bogendoerfer <tsbogend@alpha.franken.de>
      26bff9eb
    • Nathan Chancellor's avatar
      MIPS: VDSO: Allow ld.lld to link the VDSO · 22235ef3
      Nathan Chancellor authored 
      Currently, when linking with ld.lld, this warning pops up:

    arch/mips/vdso/Makefile:70: MIPS VDSO requires binutils >= 2.25

CONFIG_LD_VERSION is set with scripts/ld-version.sh, which is specific
to GNU ld. It returns 0 for ld.lld so CONFIG_MIPS_LD_CAN_LINK_VDSO does
not set.

ld.lld has a completely different versioning scheme (as it follows
LLVM's versioning) and it does not have the issue mentioned in the
comment block so it should be allowed to link the VDSO.

With this patch, the VDSO successfully links and shows P_MIPS_PC32 in
vgettimeofday.o.

$ llvm-objdump -Dr arch/mips/vdso/vgettimeofday.o | grep R_MIPS_PC32
			00000024:  R_MIPS_PC32	_start
			000000b0:  R_MIPS_PC32	_start
			000002bc:  R_MIPS_PC32	_start
			0000036c:  R_MIPS_PC32	_start
			00000468:  R_MIPS_PC32	_start
Reported-by: default avatarDmitry Golovin <dima@golovin.in>
Signed-off-by: default avatarNathan Chancellor <natechancellor@gmail.com>
Link: https://github.com/ClangBuiltLinux/linux/issues/785
Link: https://github.com/llvm/llvm-project/commit/e364e2e9ce50c12eb2bf093560e1a1a8544d455aSigned-off-by: default avatarThomas Bogendoerfer <tsbogend@alpha.franken.de>
      22235ef3
    • Nathan Chancellor's avatar
      MIPS: VDSO: Use $(LD) instead of $(CC) to link VDSO · 2ff90699
      Nathan Chancellor authored 
      Currently, the VDSO is being linked through $(CC). This does not match
how the rest of the kernel links objects, which is through the $(LD)
variable.

When clang is built in a default configuration, it first attempts to use
the target triple's default linker then the system's default linker,
unless told otherwise through -fuse-ld=... We do not use -fuse-ld=
because it can be brittle and we have support for invoking $(LD)
directly. See commit fe00e50b ("ARM: 8858/1: vdso: use $(LD)
instead of $(CC) to link VDSO") and commit 691efbed ("arm64: vdso:
use $(LD) instead of $(CC) to link VDSO") for examples of doing this in
the VDSO.

Do the same thing here. Replace the custom linking logic with $(cmd_ld)
and ldflags-y so that $(LD) is respected. We need to explicitly add two
flags to the linker that were implicitly passed by the compiler:
-G 0 (which comes from ccflags-vdso) and --eh-frame-hdr.

Before this patch (generated by adding '-v' to VDSO_LDFLAGS):

<gcc_prefix>/libexec/gcc/mips64-linux/9.3.0/collect2 \
-plugin <gcc_prefix>/libexec/gcc/mips64-linux/9.3.0/liblto_plugin.so \
-plugin-opt=<gcc_prefix>/libexec/gcc/mips64-linux/9.3.0/lto-wrapper \
-plugin-opt=-fresolution=/tmp/ccGEi5Ka.res \
--eh-frame-hdr \
-G 0 \
-EB \
-mips64r2 \
-shared \
-melf64btsmip \
-o arch/mips/vdso/vdso.so.dbg.raw \
-L<gcc_prefix>/lib/gcc/mips64-linux/9.3.0/64 \
-L<gcc_prefix>/lib/gcc/mips64-linux/9.3.0 \
-L<gcc_prefix>/lib/gcc/mips64-linux/9.3.0/../../../../mips64-linux/lib \
-Bsymbolic \
--no-undefined \
-soname=linux-vdso.so.1 \
-EB \
--hash-style=sysv \
--build-id \
-T arch/mips/vdso/vdso.lds \
arch/mips/vdso/elf.o \
arch/mips/vdso/vgettimeofday.o \
arch/mips/vdso/sigreturn.o

After this patch:

<gcc_prefix>/bin/mips64-linux-ld \
-m elf64btsmip \
-Bsymbolic \
--no-undefined \
-soname=linux-vdso.so.1 \
-EB \
-nostdlib \
-shared \
-G 0 \
--eh-frame-hdr \
--hash-style=sysv \
--build-id \
-T  arch/mips/vdso/vdso.lds \
arch/mips/vdso/elf.o \
arch/mips/vdso/vgettimeofday.o
arch/mips/vdso/sigreturn.o \
-o arch/mips/vdso/vdso.so.dbg.raw

Note that we leave behind -mips64r2. Turns out that ld ignores it (see
get_emulation in ld/ldmain.c). This is true of current trunk and 2.23,
which is the minimum supported version for the kernel:

https://sourceware.org/git/?p=binutils-gdb.git;a=blob;f=ld/ldmain.c;hb=aa4209e7b679afd74a3860ce25659e71cc4847d5#l593
https://sourceware.org/git/?p=binutils-gdb.git;a=blob;f=ld/ldmain.c;hb=a55e30b51bc6227d8d41f707654d0a5620978dcf#l641

Before this patch, LD=ld.lld did nothing:

$ llvm-readelf -p.comment arch/mips/vdso/vdso.so.dbg | sed 's/(.*//'
String dump of section '.comment':
[     0] ClangBuiltLinux clang version 11.0.0

After this patch, it does:

$ llvm-readelf -p.comment arch/mips/vdso/vdso.so.dbg | sed 's/(.*//'
String dump of section '.comment':
[     0] Linker: LLD 11.0.0
[    62] ClangBuiltLinux clang version 11.0.0

Link: https://github.com/ClangBuiltLinux/linux/issues/785Signed-off-by: default avatarNathan Chancellor <natechancellor@gmail.com>
Signed-off-by: default avatarThomas Bogendoerfer <tsbogend@alpha.franken.de>
      2ff90699
    • Nathan Chancellor's avatar
      MIPS: Unconditionally specify '-EB' or '-EL' · fd9d0ca2
      Nathan Chancellor authored 
      This was all done to work around a GCC bug that has been fixed after
4.2. The kernel requires GCC 4.6 or newer so remove all of these hacks
and just use the traditional flags.

 $ mips64-linux-gcc --version | head -n1
 mips64-linux-gcc (GCC) 4.6.3

 $ mips64-linux-gcc -EB -dM -E -C -x c /dev/null | grep MIPSE
 #define MIPSEB 1
 #define __MIPSEB__ 1
 #define _MIPSEB 1
 #define __MIPSEB 1

 $ mips64-linux-gcc -EL -dM -E -C -x c /dev/null | grep MIPSE
 #define __MIPSEL__ 1
 #define MIPSEL 1
 #define _MIPSEL 1
 #define __MIPSEL 1

This is necessary when converting the MIPS VDSO to use $(LD) instead of
$(CC) to link because the OUTPUT_FORMAT is defaulted to little endian
and only flips to big endian when '-EB' is set on the command line.
There is no issue currently because the compiler explicitly passes
'-EB' or '-EL' to the linker regardless of whether or not it was
provided by the user. Passing '-v' to VDSO_LDFLAGS shows:

<gcc_prefix>/libexec/gcc/mips64-linux/9.3.0/collect2 ... -EB ...

even though '-EB' is nowhere to be found in KBUILD_CFLAGS. The VDSO
Makefile already supports getting '-EB' or '-EL' from KBUILD_CFLAGS
through a filter directive but '-EB' or '-EL' is not always present.

If we do not do this, we will see the following error when compiling
for big endian:

$ make -j$(nproc) ARCH=mips CROSS_COMPILE=mips64-linux- \
  64r2el_defconfig arch/mips/vdso/
...
mips64-linux-ld: arch/mips/vdso/elf.o: compiled for a big endian system
and target is little endian
mips64-linux-ld: arch/mips/vdso/elf.o: endianness incompatible with that
of the selected emulation
mips64-linux-ld: failed to merge target specific data of file
arch/mips/vdso/elf.o
...

Remove this legacy hack and just use '-EB' and '-EL' unconditionally.
Reported-by: default avatarThomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: default avatarNathan Chancellor <natechancellor@gmail.com>
Signed-off-by: default avatarThomas Bogendoerfer <tsbogend@alpha.franken.de>
      fd9d0ca2
    • Nathan Chancellor's avatar
      MIPS: VDSO: Move disabling the VDSO logic to Kconfig · e91946d6
      Nathan Chancellor authored 
      After commit 9553d16f ("init/kconfig: Add LD_VERSION Kconfig"), we
have access to GNU ld's version at configuration time. As a result, we
can make it clearer under what configuration circumstances the MIPS VDSO
needs to be disabled.

This is a prerequisite for getting rid of the MIPS VDSO binutils
warning and linking the VDSO when LD is ld.lld. Wrapping the call to
ld-ifversion with CONFIG_LD_IS_LLD does not work because the config
values are wiped away during 'make clean'.
Signed-off-by: default avatarNathan Chancellor <natechancellor@gmail.com>
Signed-off-by: default avatarThomas Bogendoerfer <tsbogend@alpha.franken.de>
      e91946d6
    • Sami Tolvanen's avatar
      kbuild: add CONFIG_LD_IS_LLD · b744b43f
      Sami Tolvanen authored 
      Similarly to the CC_IS_CLANG config, add LD_IS_LLD to avoid GNU ld
specific logic such as ld-version or ld-ifversion and gain the
ability to select potential features that depend on the linker at
configuration time such as LTO.
Signed-off-by: default avatarSami Tolvanen <samitolvanen@google.com>
Acked-by: default avatarMasahiro Yamada <masahiroy@kernel.org>
[nc: Reword commit message]
Signed-off-by: default avatarNathan Chancellor <natechancellor@gmail.com>
Tested-by: default avatarSedat Dilek <sedat.dilek@gmail.com>
Reviewed-by: default avatarSedat Dilek <sedat.dilek@gmail.com>
Signed-off-by: default avatarThomas Bogendoerfer <tsbogend@alpha.franken.de>
      b744b43f
  19. 11 May, 2020 1 commit
  21. 09 May, 2020 2 commits
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