Paul Burton [Tue, 21 Aug 2018 19:12:59 +0000 (12:12 -0700)]
MIPS: lib: Provide MIPS64r6 __multi3() for GCC < 7
Some versions of GCC suboptimally generate calls to the __multi3()
intrinsic for MIPS64r6 builds, resulting in link failures due to the
missing function:
LD vmlinux.o
MODPOST vmlinux.o
kernel/bpf/verifier.o: In function `kmalloc_array':
include/linux/slab.h:631: undefined reference to `__multi3'
fs/select.o: In function `kmalloc_array':
include/linux/slab.h:631: undefined reference to `__multi3'
...
We already have a workaround for this in which we provide the
instrinsic, but we do so selectively for GCC 7 only. Unfortunately the
issue occurs with older GCC versions too - it has been observed with
both GCC 5.4.0 & GCC 6.4.0.
MIPSr6 support was introduced in GCC 5, so all major GCC versions prior
to GCC 8 are affected and we extend our workaround accordingly to all
MIPS64r6 builds using GCC versions older than GCC 8.
Signed-off-by: Paul Burton <paul.burton@mips.com> Reported-by: Vladimir Kondratiev <vladimir.kondratiev@intel.com> Fixes: ebabcf17bcd7 ("MIPS: Implement __multi3 for GCC7 MIPS64r6 builds")
Patchwork: https://patchwork.linux-mips.org/patch/20297/ Cc: James Hogan <jhogan@kernel.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Cc: stable@vger.kernel.org # 4.15+
Some versions of GCC for the MIPS architecture suffer from a bug which
can lead to instructions from beyond an unreachable statement being
incorrectly reordered into earlier branch delay slots if the unreachable
statement is the only content of a case in a switch statement. This can
lead to seemingly random behaviour, such as invalid memory accesses from
incorrectly reordered loads or stores, and link failures on microMIPS
builds.
Runtime problems resulting from this bug were initially observed using a
maltasmvp_defconfig v4.4 kernel built using GCC 4.9.2 (from a Codescape
SDK 2015.06-05 toolchain), with the result being an address exception
taken after log messages about the L1 caches (during probe of the L2
cache):
This is early enough that the kernel exception vectors are not in use,
so any further output depends upon the bootloader. This is reproducible
in QEMU where no further output occurs - ie. the system hangs here.
Given the nature of the bug it may potentially be hit with differing
symptoms. The bug is known to affect GCC versions as recent as 7.3, and
it is unclear whether GCC 8 fixed it or just happens not to encounter
the bug in the testcase found at the link above due to differing
optimizations.
This bug can be worked around by placing a volatile asm statement, which
GCC is prevented from reordering past, prior to the
__builtin_unreachable call.
That was actually done already for other reasons by commit 173a3efd3edb
("bug.h: work around GCC PR82365 in BUG()"), but creates problems for
microMIPS builds due to the lack of a .insn directive. The microMIPS ISA
allows for interlinking with regular MIPS32 code by repurposing bit 0 of
the program counter as an ISA mode bit. To switch modes one changes the
value of this bit in the PC. However typical branch instructions encode
their offsets as multiples of 2-byte instruction halfwords, which means
they cannot change ISA mode - this must be done using either an indirect
branch (a jump-register in MIPS terminology) or a dedicated jalx
instruction. In order to ensure that regular branches don't attempt to
target code in a different ISA which they can't actually switch to, the
linker will check that branch targets are code in the same ISA as the
branch.
Unfortunately our empty asm volatile statements don't qualify as code,
and the link for microMIPS builds fails with errors such as:
arch/mips/mm/dma-default.s:3265: Error: branch to a symbol in another ISA mode
arch/mips/mm/dma-default.s:5027: Error: branch to a symbol in another ISA mode
Resolve this by adding a .insn directive within the asm statement which
declares that what comes next is code. This may or may not be true,
since we don't really know what comes next, but as this code is in an
unreachable path anyway that doesn't matter since we won't execute it.
We do this in asm/compiler.h & select CONFIG_HAVE_ARCH_COMPILER_H in
order to have this included by linux/compiler_types.h after
linux/compiler-gcc.h. This will result in asm/compiler.h being included
in all C compilations via the -include linux/compiler_types.h argument
in c_flags, which should be harmless.
Signed-off-by: Paul Burton <paul.burton@mips.com> Fixes: 173a3efd3edb ("bug.h: work around GCC PR82365 in BUG()")
Patchwork: https://patchwork.linux-mips.org/patch/20270/ Cc: James Hogan <jhogan@kernel.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: linux-mips@linux-mips.org
Paul Burton [Mon, 20 Aug 2018 22:36:17 +0000 (15:36 -0700)]
compiler.h: Allow arch-specific asm/compiler.h
We have a need to override the definition of
barrier_before_unreachable() for MIPS, which means we either need to add
architecture-specific code into linux/compiler-gcc.h or we need to allow
the architecture to provide a header that can define the macro before
the generic definition. The latter seems like the better approach.
A straightforward approach to the per-arch header is to make use of
asm-generic to provide a default empty header & adjust architectures
which don't need anything specific to make use of that by adding the
header to generic-y. Unfortunately this doesn't work so well due to
commit 28128c61e08e ("kconfig.h: Include compiler types to avoid missed
struct attributes") which caused linux/compiler_types.h to be included
in the compilation of every C file via the -include linux/kconfig.h flag
in c_flags.
Because the -include flag is present for all C files we compile, we need
the architecture-provided header to be present before any C files are
compiled. If any C files can be compiled prior to the asm-generic header
wrappers being generated then we hit a build failure due to missing
header. Such cases do exist - one pointed out by the kbuild test robot
is the compilation of arch/ia64/kernel/nr-irqs.c, which occurs as part
of the archprepare target [1].
This leaves us with a few options:
1) Use generic-y & fix any build failures we find by enforcing
ordering such that the asm-generic target occurs before any C
compilation, such that linux/compiler_types.h can always include
the generated asm-generic wrapper which in turn includes the empty
asm-generic header. This would rely on us finding all the
problematic cases - I don't know for sure that the ia64 issue is
the only one.
2) Add an actual empty header to each architecture, so that we don't
need the generated asm-generic wrapper. This seems messy.
3) Give up & add #ifdef CONFIG_MIPS or similar to
linux/compiler_types.h. This seems messy too.
4) Include the arch header only when it's actually needed, removing
the need for the asm-generic wrapper for all other architectures.
This patch allows us to use approach 4, by including an asm/compiler.h
header from linux/compiler_types.h after the inclusion of the
compiler-specific linux/compiler-*.h header(s). We do this
conditionally, only when CONFIG_HAVE_ARCH_COMPILER_H is selected, in
order to avoid the need for asm-generic wrappers & the associated build
ordering issue described above. The asm/compiler.h header is included
after the generic linux/compiler-*.h header(s) for consistency with the
way linux/compiler-intel.h & linux/compiler-clang.h are included after
the linux/compiler-gcc.h header that they override.
Paul Burton [Fri, 17 Aug 2018 22:36:24 +0000 (15:36 -0700)]
MIPS: Avoid move psuedo-instruction whilst using MIPS_ISA_LEVEL
MIPS_ISA_LEVEL is always defined as the 64 bit ISA that is a compatible
superset of the ISA that the kernel build is targeting, and is used to
allow us to emit instructions that we may detect support for at runtime.
When we use a .set MIPS_ISA_LEVEL directive & are building a 32-bit
kernel, we therefore are temporarily allowing the assembler to generate
MIPS64 instructions. Using the move pseudo-instruction whilst this is
the case is problematic because the assembler is likely to emit a daddu
instruction which will generate a reserved instruction exception when
executed on a MIPS32 machine.
Unfortunately the combination of commit a0a5ac3ce8fe ("MIPS: Fix delay
slot bug in `atomic*_sub_if_positive' for R10000_LLSC_WAR") and commit 4936084c2ee2 ("MIPS: Cleanup R10000_LLSC_WAR logic in atomic.h") causes
us to do exactly this in atomic_sub_if_positive(), and the result is
MIPS64 daddu instructions in 32-bit kernels.
Fix this by using .set mips0 to restore the default ISA after the ll
instruction, and use .set MIPS_ISA_LEVEL again prior to the sc. This
ensures everything but the ll & sc are assembled using the default ISA
for the kernel build & the move pseudo-instruction is emitted as a
MIPS32 addu instruction.
We appear to have another pre-existing instance of the same issue in our
atomic_fetch_*_relaxed() functions, and fix that up too by moving our
.set move0 such that it occurs prior to use of the move
pseudo-instruction.
Signed-off-by: Paul Burton <paul.burton@mips.com> Fixes: a0a5ac3ce8fe ("MIPS: Fix delay slot bug in `atomic*_sub_if_positive' for R10000_LLSC_WAR") Fixes: 4936084c2ee2 ("MIPS: Cleanup R10000_LLSC_WAR logic in atomic.h")
Patchwork: https://patchwork.linux-mips.org/patch/20253/ Cc: James Hogan <jhogan@kernel.org> Cc: Joshua Kinard <kumba@gentoo.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org
Paul Burton [Fri, 10 Aug 2018 23:03:31 +0000 (16:03 -0700)]
MIPS: Consistently declare TLB functions
Since at least the beginning of the git era we've declared our TLB
exception handling functions inconsistently. They're actually functions,
but we declare them as arrays of u32 where each u32 is an encoded
instruction. This has always been the case for arch/mips/mm/tlbex.c, and
has also been true for arch/mips/kernel/traps.c since commit 86a1708a9d54 ("MIPS: Make tlb exception handler definitions and
declarations match.") which aimed for consistency but did so by
consistently making the our C code inconsistent with our assembly.
This is all usually harmless, but when using GCC 7 or newer to build a
kernel targeting microMIPS (ie. CONFIG_CPU_MICROMIPS=y) it becomes
problematic. With microMIPS bit 0 of the program counter indicates the
ISA mode. When bit 0 is zero instructions are decoded using the standard
MIPS32 or MIPS64 ISA. When bit 0 is one instructions are decoded using
microMIPS. This means that function pointers become odd - their least
significant bit is one for microMIPS code. We work around this in cases
where we need to access code using loads & stores with our
msk_isa16_mode() macro which simply clears bit 0 of the value it is
given:
#define msk_isa16_mode(x) ((x) & ~0x1)
For example we do this for our TLB load handler in
build_r4000_tlb_load_handler():
We then write code to p, expecting it to be suitably aligned (our LEAF
macro aligns functions on 4 byte boundaries, so (ulong)handle_tlbl will
give a value one greater than a multiple of 4 - ie. the start of a
function on a 4 byte boundary, with the ISA mode bit 0 set).
This worked fine up to GCC 6, but GCC 7 & onwards is smart enough to
presume that handle_tlbl which we declared as an array of u32s must be
aligned sufficiently that bit 0 of its address will never be set, and as
a result optimize out msk_isa16_mode(). This leads to p having an
address with bit 0 set, and when we go on to attempt to store code at
that address we take an address error exception due to the unaligned
memory access.
This leads to an exception prior to the kernel having configured its own
exception handlers, so we jump to whatever handlers the bootloader
configured. In the case of QEMU this results in a silent hang, since it
has no useful general exception vector.
Fix this by consistently declaring our TLB-related functions as
functions. For handle_tlbl(), handle_tlbs() & handle_tlbm() we do this
in asm/tlbex.h & we make use of the existing declaration of
tlbmiss_handler_setup_pgd() in asm/mmu_context.h. Our TLB handler
generation code in arch/mips/mm/tlbex.c is adjusted to deal with these
definitions, in most cases simply by casting the function pointers to
u32 pointers.
This allows us to include asm/mmu_context.h in arch/mips/mm/tlbex.c to
get the definitions of tlbmiss_handler_setup_pgd & pgd_current, removing
some needless duplication. Consistently using msk_isa16_mode() on
function pointers means we no longer need the
tlbmiss_handler_setup_pgd_start symbol so that is removed entirely.
Now that we're declaring our functions as functions GCC stops optimizing
out msk_isa16_mode() & a microMIPS kernel built with either GCC 7.3.0 or
8.1.0 boots successfully.
Paul Burton [Fri, 10 Aug 2018 22:24:39 +0000 (15:24 -0700)]
MIPS: Export tlbmiss_handler_setup_pgd near its definition
We export tlbmiss_handler_setup_pgd in arch/mips/mm/tlbex.c close to a
declaration of it, rather than close to its definition as is standard.
We've supported exporting symbols in assembly code since commit 22823ab419d8 ("EXPORT_SYMBOL() for asm"), so move the export to follow
the function's (stub) definition.
Paul Burton [Thu, 9 Aug 2018 21:43:42 +0000 (14:43 -0700)]
MIPS: Remove remnants of UASM_ISA
Commit 33679a50370d ("MIPS: uasm: Remove needless ISA abstraction")
removed use of the MIPS_ISA preprocessor macro, but left a couple of
unused definitions of it behind.
Paul Burton [Wed, 8 Aug 2018 16:30:56 +0000 (09:30 -0700)]
MIPS: netlogic: xlr: Remove erroneous check in nlm_fmn_send()
In nlm_fmn_send() we have a loop which attempts to send a message
multiple times in order to handle the transient failure condition of a
lack of available credit. When examining the status register to detect
the failure we check for a condition that can never be true, which falls
foul of gcc 8's -Wtautological-compare:
In file included from arch/mips/netlogic/common/irq.c:65:
./arch/mips/include/asm/netlogic/xlr/fmn.h: In function 'nlm_fmn_send':
./arch/mips/include/asm/netlogic/xlr/fmn.h:304:22: error: bitwise
comparison always evaluates to false [-Werror=tautological-compare]
if ((status & 0x2) == 1)
^~
If the path taken if this condition were true all we do is print a
message to the kernel console. Since failures seem somewhat expected
here (making the console message questionable anyway) and the condition
has clearly never evaluated true we simply remove it, rather than
attempting to fix it to check status correctly.
Signed-off-by: Paul Burton <paul.burton@mips.com>
Patchwork: https://patchwork.linux-mips.org/patch/20174/ Cc: Ganesan Ramalingam <ganesanr@broadcom.com> Cc: James Hogan <jhogan@kernel.org> Cc: Jayachandran C <jnair@caviumnetworks.com> Cc: John Crispin <john@phrozen.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org
Paul Burton [Tue, 7 Aug 2018 23:09:56 +0000 (16:09 -0700)]
MIPS: VDSO: Force link endianness
When building the VDSO with clang it appears to invoke ld without
specifying endianness, even though clang itself was provided with a -EB
or -EL flag. This results in the build failing due to a mismatch between
the objects that are the input to ld, and the output it is attempting to
create:
VDSO arch/mips/vdso/vdso.so.dbg.raw
mips-linux-ld: arch/mips/vdso/elf.o: compiled for a big endian system
and target is little endian
mips-linux-ld: arch/mips/vdso/elf.o: endianness incompatible with that
of the selected emulation
mips-linux-ld: failed to merge target specific data of file
arch/mips/vdso/elf.o
...
Work around this problem by explicitly specifying the link endianness
using -Wl,-EB or -Wl,-EL when -EB or -EL are part of KBUILD_CFLAGS. This
resolves the build failure when using clang, and doesn't have any
negative effect on gcc.
Paul Burton [Tue, 7 Aug 2018 23:06:41 +0000 (16:06 -0700)]
MIPS: Always specify -EB or -EL when using clang
When building using clang, always specify -EB or -EL in order to ensure
we target the desired endianness.
Since clang cross compiles using a single compiler build with multiple
targets, our -dumpmachine tests which don't specify clang's --target
argument check output based upon the build machine rather than the
machine our build will target. This means our detection of whether to
specify -EB fails miserably & we never do. Providing the endianness flag
unconditionally for clang resolves this issue & simplifies the clang
path somewhat.
Paul Burton [Tue, 7 Aug 2018 17:15:04 +0000 (10:15 -0700)]
MIPS: Use dins to simplify __write_64bit_c0_split()
The code in __write_64bit_c0_split() is used by MIPS32 kernels running
on MIPS64 CPUs to write a 64-bit value to a 64-bit coprocessor 0
register using a single 64-bit dmtc0 instruction. It does this by
combining the 2x 32-bit registers used to hold the 64-bit value into a
single register, which in the existing code involves three steps:
1) Zero extend register A which holds bits 31:0 of our data, since it
may have previously held a sign-extended value.
2) Shift register B which holds bits 63:32 of our data in bits 31:0
left by 32 bits, such that the bits forming our data are in the
position they'll be in the final 64-bit value & bits 31:0 of the
register are zero.
3) Or the two registers together to form the 64-bit value in one
64-bit register.
From MIPS r2 onwards we have a dins instruction which can effectively
perform all 3 of those steps using a single instruction.
Add a path for MIPS r2 & beyond which uses dins to take bits 31:0 from
register B & insert them into bits 63:32 of register A, giving us our
full 64-bit value in register A with one instruction.
Since we know that MIPS r2 & above support the sel field for the dmtc0
instruction, we don't bother special casing sel==0. Omiting the sel
field would assemble to exactly the same instruction as when we
explicitly specify that it equals zero.
Paul Burton [Tue, 7 Aug 2018 01:29:51 +0000 (18:29 -0700)]
MIPS: Use read-write output operand in __write_64bit_c0_split()
Commit c22c80431055 ("MIPS: Fix input modify in
__write_64bit_c0_split()") modified __write_64bit_c0_split() constraints
such that we have both an input & an output which we hope to assign to
the same registers, and modify the output rather than incorrectly
clobbering an input.
The way in which we use both an output & an input parameter with the
input constrained to share the output registers is a little convoluted &
also problematic for clang, which complains if the input & output values
have different widths. For example:
In file included from kernel/fork.c:98:
./arch/mips/include/asm/mmu_context.h:149:19: error: unsupported
inline asm: input with type 'unsigned long' matching output with
type 'unsigned long long'
write_c0_entryhi(cpu_asid(cpu, next));
~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~
./arch/mips/include/asm/mmu_context.h:93:2: note: expanded from macro
'cpu_asid'
(cpu_context((cpu), (mm)) & cpu_asid_mask(&cpu_data[cpu]))
^
./arch/mips/include/asm/mipsregs.h:1617:65: note: expanded from macro
'write_c0_entryhi'
#define write_c0_entryhi(val) __write_ulong_c0_register($10, 0, val)
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~
./arch/mips/include/asm/mipsregs.h:1430:39: note: expanded from macro
'__write_ulong_c0_register'
__write_64bit_c0_register(reg, sel, val); \
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~
./arch/mips/include/asm/mipsregs.h:1400:41: note: expanded from macro
'__write_64bit_c0_register'
__write_64bit_c0_split(register, sel, value); \
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~
./arch/mips/include/asm/mipsregs.h:1498:13: note: expanded from macro
'__write_64bit_c0_split'
: "r,0" (val)); \
^~~
We can both fix this build failure & simplify the code somewhat by
assigning the __tmp variable with the input value in C prior to our
inline assembly, and then using a single read-write output operand (ie.
a constraint beginning with +) to provide this value to our assembly.
Paul Burton [Tue, 7 Aug 2018 01:18:52 +0000 (18:18 -0700)]
MIPS: Avoid using array as parameter to write_c0_kpgd()
Passing an array (swapper_pg_dir) as the argument to write_c0_kpgd() in
setup_pw() will become problematic if we modify __write_64bit_c0_split()
to cast its val argument to unsigned long long, because for 32-bit
kernel builds the size of a pointer will differ from the size of an
unsigned long long. This would fall foul of gcc's pointer-to-int-cast
diagnostic.
Cast the value to a long, which should be the same width as the pointer
that we ultimately want & will be sign extended if required to the
unsigned long long that __write_64bit_c0_split() ultimately needs.
Paul Burton [Mon, 6 Aug 2018 22:24:27 +0000 (15:24 -0700)]
MIPS: vdso: Allow clang's --target flag in VDSO cflags
The MIPS VDSO code filters out a subset of known-good flags from
KBUILD_CFLAGS to use when building VDSO libraries. When we build using
clang we need to allow the --target flag through, otherwise we'll
generally attempt to build the VDSO for the architecture of the build
machine rather than for MIPS.
Signed-off-by: Paul Burton <paul.burton@mips.com>
Patchwork: https://patchwork.linux-mips.org/patch/20154/ Cc: James Hogan <jhogan@kernel.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org
Paul Burton [Mon, 6 Aug 2018 22:24:25 +0000 (15:24 -0700)]
MIPS: genvdso: Remove GOT checks
Our genvdso tool performs some rather paranoid checking that the VDSO
library isn't attempting to make use of a GOT by constraining the number
of entries that the GOT is allowed to contain to the minimum 2 entries
that are always generated by binutils.
Unfortunately lld prior to revision 334390 generates a third entry,
which is unused & thus harmless but falls foul of genvdso's checks &
causes the build to fail.
Since we already check that the VDSO contains no relocations it seems
reasonable to presume that it also doesn't contain use of a GOT, which
would involve relocations. Thus rather than attempting to work around
this issue by allowing 3 GOT entries when using lld, simply remove the
GOT checks which seem overly paranoid.
Signed-off-by: Paul Burton <paul.burton@mips.com>
Patchwork: https://patchwork.linux-mips.org/patch/20152/ Cc: James Hogan <jhogan@kernel.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org
MIPS: Remove obsolete MIPS checks for DST node "chosen@0"
As there is precious little left in any DTS files referring to the
node "/chosen@0" as opposed to "/chosen", remove the two checks for
the former node name.
[paul.burton@mips.com:
The modified yamon-dt code only operates on
arch/mips/boot/dts/mti/sead3.dts right now, and that uses chosen
rather than chosen@0 anyway, so this should have no behavioural
effect.]
Signed-off-by: Robert P. J. Day <rpjday@crashcourse.ca> Signed-off-by: Paul Burton <paul.burton@mips.com>
Patchwork: https://patchwork.linux-mips.org/patch/20131/ Cc: linux-mips@linux-mips.org
Paul Burton [Thu, 2 Aug 2018 16:23:30 +0000 (09:23 -0700)]
MIPS: generic: Remove input symbols from defconfig
generic_defconfig explicitly disables CONFIG_INPUT_MOUSEDEV,
CONFIG_INPUT_KEYBOARD & CONFIG_INPUT_MOUSE which results in warnings
when merging board config fragments if any of them require these
options. This is the case for the ranchu board, which means we've had
the following warning when configuring for generic platform targets
since commit f2d0b0d5c171 ("MIPS: ranchu: Add Ranchu as a new
generic-based board"):
$ make ARCH=mips 32r2el_defconfig
Using ./arch/mips/configs/generic_defconfig as base
Merging arch/mips/configs/generic/32r2.config
Merging arch/mips/configs/generic/el.config
Merging ./arch/mips/configs/generic/board-sead-3.config
Merging ./arch/mips/configs/generic/board-ranchu.config
Value of CONFIG_INPUT_KEYBOARD is redefined by fragment ./arch/mips/configs/generic/board-ranchu.config:
Previous value: # CONFIG_INPUT_KEYBOARD is not set
New value: CONFIG_INPUT_KEYBOARD=y
Merging ./arch/mips/configs/generic/board-ni169445.config
Merging ./arch/mips/configs/generic/board-boston.config
Merging ./arch/mips/configs/generic/board-ocelot.config
Merging ./arch/mips/configs/generic/board-xilfpga.config
scripts/kconfig/conf --olddefconfig Kconfig
#
# configuration written to .config
#
Resolve this by removing mention of the CONFIG_INPUT_* Kconfig symbols
from generic_defconfig, allowing them to take their default values &
allowing board config fragments to enable them without warnings.
This may be problematic if CONFIG_ARCH_MIGHT_HAVE_PC_SERIO is ever
enabled for CONFIG_MIPS_GENERIC=y configurations, but for now that isn't
the case so we can worry about that if & when it happens.
Signed-off-by: Paul Burton <paul.burton@mips.com>
Patchwork: https://patchwork.linux-mips.org/patch/20109/ Cc: James Hogan <jhogan@kernel.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org
Paul Burton [Wed, 1 Aug 2018 20:15:18 +0000 (13:15 -0700)]
MIPS: Delete unused code in linux32.c
The A() & AA() macros have been unused since commit 05e4396651ca
("[MIPS] Use SYSVIPC_COMPAT to fix various problems on N32"), which
switched to the more standard compat_ptr().
RLIM_INFINITY32, RESOURCE32() & struct rlimit32 have been present but
unused since the beginning of the git era.
Remove the dead code.
Signed-off-by: Paul Burton <paul.burton@mips.com>
Patchwork: https://patchwork.linux-mips.org/patch/20108/ Cc: James Hogan <jhogan@kernel.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org
Paul Burton [Wed, 1 Aug 2018 20:15:17 +0000 (13:15 -0700)]
MIPS: Remove unused sys_32_mmap2
The sys_32_mmap2 function has been unused since we started using syscall
wrappers in commit dbda6ac08976 ("MIPS: CVE-2009-0029: Enable syscall
wrappers."), and is indeed identical to the sys_mips_mmap2 function that
replaced it in sys32_call_table.
Remove the dead code.
Signed-off-by: Paul Burton <paul.burton@mips.com>
Patchwork: https://patchwork.linux-mips.org/patch/20107/ Cc: James Hogan <jhogan@kernel.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org
Paul Burton [Wed, 1 Aug 2018 20:12:42 +0000 (13:12 -0700)]
MIPS: Remove nabi_no_regargs
Our sigreturn functions make use of a macro named nabi_no_regargs to
declare 8 dummy arguments to a function, forcing the compiler to expect
a pt_regs structure on the stack rather than in argument registers. This
is an ugly hack which unnecessarily causes these sigreturn functions to
need to care about the calling convention of the ABI the kernel is built
for. Although this is abstracted via nabi_no_regargs, it's still ugly &
unnecessary.
Remove nabi_no_regargs & the struct pt_regs argument from sigreturn
functions, and instead use current_pt_regs() to find the struct pt_regs
on the stack, which works cleanly regardless of ABI.
Signed-off-by: Paul Burton <paul.burton@mips.com>
Patchwork: https://patchwork.linux-mips.org/patch/20106/ Cc: James Hogan <jhogan@kernel.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org
Systems based upon the Loongson 1B & 1C CPUs share the same load
address, as do those based upon Loongson 1A. Unify the definition of
this load address to reduce duplication & avoid the need for an extra
Loongson 1A case in future.
LS232 (Loonson 2-issue 32-bit, also called GS232 (Godson 2-issue 32-bit))
is the CPU core (microarchitecture) of Loongson 1A/1B/1C.
According to "LS232 用户手册 (LS232 User Manual)", LS232 implements the
MIPS32 Release 1 instruction set, and part of the MIPS32 Release 2
instruction set.
In the manual, LS232 implements all of the MIPS32R2 instruction set
except the FPU instructions, and LS232 also implements 5 FPU
instructions of the MIPS32R2 instruction set: CEIL.L.fmt, CVT.L.fmt,
FLOOR.L.fmt, TRUNC.L.fmt, and ROUND.L.fmt.
But a bug of the DI instruction has been found during tests, the DI
instruction can not disable interrupts in arch_local_irq_disable() with
CONFIG_PREEMPT_NONE=y and CFLAGS='-mno-branch-likely' in some cases.
[paul.burton@mips.com:
- Remove the _MIPS_ISA redefinition to match the change made for the
generic MIPSr1 CPUs by commit 344ebf09949c ("MIPS: Always use
-march=<arch>, not -<arch> shortcuts").]
Paul Burton [Sat, 28 Jul 2018 01:23:21 +0000 (18:23 -0700)]
MIPS: generic: Select MIPS_AUTO_PFN_OFFSET
Enable CONFIG_MIPS_AUTO_PFN_OFFSET for the generic platform, allowing
it to avoid wasted book-keeping for pages with addresses lower than the
physical base address of memory.
This has a minimal impact on kernel text size, with 64r6el_defconfig
gaining 0.1% in size as reported by bloat-o-meter:
The gain for systems with large offsets to physical memory & the ability
to continue using generic kernels on such systems seems well worth this
small cost.
Signed-off-by: Paul Burton <paul.burton@mips.com> Suggested-by: Vladimir Kondratiev <vladimir.kondratiev@intel.com>
Patchwork: https://patchwork.linux-mips.org/patch/20049/ Cc: James Hogan <jhogan@kernel.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org
Paul Burton [Sat, 28 Jul 2018 01:23:20 +0000 (18:23 -0700)]
MIPS: Allow auto-dection of ARCH_PFN_OFFSET & PHYS_OFFSET
On systems where physical memory begins at a non-zero address, defining
PHYS_OFFSET (which influences ARCH_PFN_OFFSET) can save us time & memory
by avoiding book-keeping for pages from address zero to the start of
memory.
Some MIPS platforms already make use of this, but with the definition of
PHYS_OFFSET being compile-time constant it hasn't been possible to
enable this optimization for a kernel which may run on systems with
varying physical memory base addresses.
Introduce a new Kconfig option CONFIG_MIPS_AUTO_PFN_OFFSET which, when
enabled, makes ARCH_PFN_OFFSET a variable & detects it from the boot
memory map (which for example may have been populated from DT). The
relationship with PHYS_OFFSET is reversed, with PHYS_OFFSET now being
based on ARCH_PFN_OFFSET. This is because ARCH_PFN_OFFSET is used far
more often, so avoiding the need for runtime calculation gives us a
smaller impact on kernel text size (0.1% rather than 0.15% for
64r6el_defconfig).
Signed-off-by: Paul Burton <paul.burton@mips.com> Suggested-by: Vladimir Kondratiev <vladimir.kondratiev@intel.com>
Patchwork: https://patchwork.linux-mips.org/patch/20048/ Cc: James Hogan <jhogan@kernel.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org
Paul Burton [Sat, 28 Jul 2018 01:23:19 +0000 (18:23 -0700)]
MIPS: Fix ISA virt/bus conversion for non-zero PHYS_OFFSET
isa_virt_to_bus() & isa_bus_to_virt() claim to treat ISA bus addresses
as being identical to physical addresses, but they fail to do so in the
presence of a non-zero PHYS_OFFSET.
Correct this by having them use virt_to_phys() & phys_to_virt(), which
consolidates the calculations to one place & ensures that ISA bus
addresses do indeed match physical addresses.
Signed-off-by: Paul Burton <paul.burton@mips.com>
Patchwork: https://patchwork.linux-mips.org/patch/20047/ Cc: James Hogan <jhogan@kernel.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Cc: Vladimir Kondratiev <vladimir.kondratiev@intel.com>
Paul Burton [Sat, 28 Jul 2018 01:23:18 +0000 (18:23 -0700)]
MIPS: Make (UN)CAC_ADDR() PHYS_OFFSET-agnostic
Converting an address between cached & uncached (typically addresses in
(c)kseg0 & (c)kseg1 or 2 xkphys regions) should not depend upon
PHYS_OFFSET in any way - we're converting from a virtual address in one
unmapped region to a virtual address in another unmapped region.
For some reason our CAC_ADDR() & UNCAC_ADDR() macros make use of
PAGE_OFFSET, which typically includes PHYS_OFFSET. This means that
platforms with a non-zero PHYS_OFFSET typically have to workaround
miscalculation by these 2 macros by also defining UNCAC_BASE to a value
that isn't really correct.
It appears that an attempt has previously been made to address this with
commit 3f4579252aa1 ("MIPS: make CAC_ADDR and UNCAC_ADDR account for
PHYS_OFFSET") which was later undone by commit ed3ce16c3d2b ("Revert
"MIPS: make CAC_ADDR and UNCAC_ADDR account for PHYS_OFFSET"") which
also introduced the ar7 workaround. That attempt at a fix was roughly
equivalent, but essentially caused the CAC_ADDR() & UNCAC_ADDR() macros
to cancel out PHYS_OFFSET by adding & then subtracting it again. In his
revert Leonid is correct that using PHYS_OFFSET makes no sense in the
context of these macros, but appears to have missed its inclusion via
PAGE_OFFSET which means PHYS_OFFSET actually had an effect after the
revert rather than before it.
Here we fix this by modifying CAC_ADDR() & UNCAC_ADDR() to stop using
PAGE_OFFSET (& thus PHYS_OFFSET), instead using __pa() & __va() along
with UNCAC_BASE.
For UNCAC_ADDR(), __pa() will convert a cached address to a physical
address which we can simply use as an offset from UNCAC_BASE to obtain
an address in the uncached region.
For CAC_ADDR() we can undo the effect of UNCAC_ADDR() by subtracting
UNCAC_BASE and using __va() on the result.
With this change made, remove definitions of UNCAC_BASE from the ar7 &
pic32 platforms which appear to have defined them only to workaround
this problem.
Signed-off-by: Paul Burton <paul.burton@mips.com>
References: 3f4579252aa1 ("MIPS: make CAC_ADDR and UNCAC_ADDR account for PHYS_OFFSET")
References: ed3ce16c3d2b ("Revert "MIPS: make CAC_ADDR and UNCAC_ADDR account for PHYS_OFFSET"")
Patchwork: https://patchwork.linux-mips.org/patch/20046/ Cc: Florian Fainelli <f.fainelli@gmail.com> Cc: James Hogan <jhogan@kernel.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Cc: Vladimir Kondratiev <vladimir.kondratiev@intel.com>
of_find_compatible_node() returns a device_node pointer with refcount
incremented and must be decremented explicitly.
As this code is using the result only to check presence of the interrupt
controller (!NULL) but not actually using the result otherwise the
refcount can be decremented here immediately again.
Signed-off-by: Nicholas Mc Guire <hofrat@osadl.org> Signed-off-by: Paul Burton <paul.burton@mips.com>
Patchwork: https://patchwork.linux-mips.org/patch/19820/ Cc: Ralf Baechle <ralf@linux-mips.org> Cc: James Hogan <jhogan@kernel.org> Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org
Paul Burton [Tue, 12 Dec 2017 09:57:47 +0000 (09:57 +0000)]
MIPS: VDSO: Prevent use of smp_processor_id()
VDSO code should not be using smp_processor_id(), since it is executed
in user mode.
Introduce a VDSO-specific path which will cause a compile-time
or link-time error (depending upon support for __compiletime_error) if
the VDSO ever incorrectly attempts to use smp_processor_id().
[Matt Redfearn <matt.redfearn@imgtec.com>: Move before change to
smp_processor_id in series]
Signed-off-by: Paul Burton <paul.burton@mips.com> Signed-off-by: Matt Redfearn <matt.redfearn@mips.com>
Patchwork: https://patchwork.linux-mips.org/patch/17932/ Cc: Ralf Baechle <ralf@linux-mips.org> Cc: James Hogan <jhogan@kernel.org> Cc: linux-mips@linux-mips.org
mips_swiotlb_ops differs from the generic swiotlb_dma_ops only in that
it contains a mb() barrier after each operations that maps or syncs
dma memory to the device.
The dma operations are defined to not be memory barriers, but instead
the write* operations to kick the DMA off are supposed to contain them.
For mips this handled by war_io_reorder_wmb(), which evaluates to the
stronger wmb() instead of the pure compiler barrier barrier() for
just those platforms that use swiotlb, so I think we are covered
properly.
[paul.burton@mips.com:
- Include linux/swiotlb.h to fix build failures for configs with
CONFIG_SWIOTLB=y.]
Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Paul Burton <paul.burton@mips.com>
Patchwork: https://patchwork.linux-mips.org/patch/20038/ Cc: David Daney <ddaney@caviumnetworks.com> Cc: Huacai Chen <chenhc@lemote.com> Cc: linux-mips@linux-mips.org Cc: iommu@lists.linux-foundation.org Cc: linux-kernel@vger.kernel.org
Paul Burton [Fri, 25 Nov 2016 18:46:09 +0000 (18:46 +0000)]
MIPS: WARN_ON invalid DMA cache maintenance, not BUG_ON
If a driver causes DMA cache maintenance with a zero length then we
currently BUG and kill the kernel. As this is a scenario that we may
well be able to recover from, WARN & return in the condition instead.
Alban Bedel [Mon, 13 Feb 2017 22:25:46 +0000 (23:25 +0100)]
MIPS: ath79: Fix the USB PHY reset names
The binding for the USB PHY went thru before the driver. However the
new version of the driver now use the PHY core support for reset, and
this expect the reset to be named "phy". So remove the "usb-" prefix
from the the reset names.
Signed-off-by: Alban Bedel <albeu@free.fr> Acked-by: Rob Herring <robh@kernel.org> Signed-off-by: Paul Burton <paul.burton@mips.com>
Patchwork: https://patchwork.linux-mips.org/patch/15282/ Cc: linux-kernel@vger.kernel.org Cc: Rob Herring <robh+dt@kernel.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Antony Pavlov <antonynpavlov@gmail.com> Cc: devicetree@vger.kernel.org Cc: linux-mips@linux-mips.org
There is an additional MIIM (MDIO) bus in this SoC so let's declare it
in the dtsi.
This bus requires GPIO 14 and 15 pins that need to be muxed. There is no
support for internal PHY reset on this bus on the contrary of MIIM0 so
there is only one register address space and not two.
MIPS: mscc: ocelot: fix length of memory address space for MIIM
The length of memory address space for MIIM0 is from 0x7107009c to
0x710700bf included which is 36 bytes long in decimal, or 0x24 bytes in
hexadecimal and not 0x36.
The ar724x pci driver expects the PCIe controller to be brought out of
reset by the bootloader.
At least the AVM Fritz 300E bootloader doesn't take care of releasing
the different PCIe controller related resets which causes an endless
hang as soon as either the PCIE Reset register (0x180f0018) or the PCI
Application Control register (0x180f0000) is read from.
Do the full "PCIE Root Complex Initialization Sequence" if the PCIe
host controller is still in reset during probing.
The QCA u-boot sleeps 10ms after the PCIE Application Control bit is
set to ready. It has been shown that 10ms might not be enough time if
PCIe should be used right after setting the bit. During my tests it
took up to 20ms till the link was up. Giving the link up to 100ms
should work for all cases.
Signed-off-by: Mathias Kresin <dev@kresin.me> Signed-off-by: John Crispin <john@phrozen.org> Signed-off-by: Paul Burton <paul.burton@mips.com>
Patchwork: https://patchwork.linux-mips.org/patch/19916/ Cc: James Hogan <jhogan@kernel.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org
Steven J. Hill [Tue, 5 Jun 2018 05:24:51 +0000 (00:24 -0500)]
MIPS: Octeon: Remove extern declarations.
Get rid of extern declarations in .c functions and included
the necessary header file. Also remove unused UART declares.
Signed-off-by: Steven J. Hill <steven.hill@cavium.com> Signed-off-by: Paul Burton <paul.burton@mips.com>
Patchwork: https://patchwork.linux-mips.org/patch/19477/ Cc: linux-mips@linux-mips.org
Matt Redfearn [Wed, 23 May 2018 13:39:59 +0000 (14:39 +0100)]
MIPS: memset.S: Add comments to fault fixup handlers
It is not immediately obvious what the expected inputs to these fault
handlers is and how they calculate the number of unset bytes. Having
stared deeply at this in order to fix some corner cases, add some
comments to assist those who follow.
Signed-off-by: Matt Redfearn <matt.redfearn@mips.com> Signed-off-by: Paul Burton <paul.burton@mips.com>
Patchwork: https://patchwork.linux-mips.org/patch/19339/ Cc: James Hogan <jhogan@kernel.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: <linux-mips@linux-mips.org> Cc: <linux-kernel@vger.kernel.org>
Matt Redfearn [Wed, 23 May 2018 13:39:58 +0000 (14:39 +0100)]
MIPS: memset.S: Fix byte_fixup for MIPSr6
The __clear_user function is defined to return the number of bytes that
could not be cleared. From the underlying memset / bzero implementation
this means setting register a2 to that number on return. Currently if a
page fault is triggered within the MIPSr6 version of setting of initial
unaligned bytes, the value loaded into a2 on return is meaningless.
During the MIPSr6 version of the initial unaligned bytes block, register
a2 contains the number of bytes to be set beyond the initial unaligned
bytes. The t0 register is initally set to the number of unaligned bytes
- STORSIZE, effectively a negative version of the number of unaligned
bytes. This is then incremented before each byte is saved.
The label .Lbyte_fixup\@ is jumped to on page fault. Currently the value
in a2 is incorrectly replaced by 0 - t0 + 1, effectively the number of
unaligned bytes remaining. This leads to the failures being reported by
the following test code:
static int __init test_clear_user(void)
{
int j, k;
Which reports:
[ 3.965439] Testing clear_user
[ 3.973169] clear_user (NULL 8) returned 6
[ 3.976782] clear_user (NULL 9) returned 6
[ 3.980390] clear_user (NULL 10) returned 6
[ 3.984052] clear_user (NULL 11) returned 6
[ 3.987524] clear_user (NULL 12) returned 6
Fix this by subtracting t0 from a2 (rather than $0), effectivey giving:
unset_bytes = (#bytes - (#unaligned bytes)) - (-#unaligned bytes remaining + 1) + 1
a2 = a2 - t0 + 1
This fixes the value returned from __clear user when the number of bytes
to set is > LONGSIZE and the address is invalid and unaligned.
Unfortunately, this breaks the fixup handling for unaligned bytes after
the final long, where register a2 still contains the number of bytes
remaining to be set and the t0 register is to 0 - the number of
unaligned bytes remaining.
Because t0 is now is now subtracted from a2 rather than 0, the number of
bytes unset is reported incorrectly:
static int __init test_clear_user(void)
{
char *test;
int j, k;
pr_info("\n\n\nTesting clear_user\n");
test = vmalloc(PAGE_SIZE);
Paul Burton [Mon, 12 Jun 2017 18:54:23 +0000 (11:54 -0700)]
MIPS: Hardcode cpu_has_* where known at compile time due to ISA
Many architectural features have over time moved from being optional to
either be required or removed by newer architecture releases. This means
that in many cases we can know at compile time whether a feature will be
supported or not purely due to the knowledge we have about the ISA the
kernel build is targeting.
This patch introduces a bunch of utility macros for checking for
supported options, ASEs & combinations of those with ISA revisions. It
then makes use of these in the default definitions of cpu_has_* macros.
The result is that many of the macros become compile-time constant,
allowing more optimisation opportunities for the compiler - particularly
with kernels built for later ISA revisions.
To demonstrate the effect of this patch, the following table shows the
size in bytes of the kernel binary as reported by scripts/bloat-o-meter
for v4.12-rc4 maltasmvp_defconfig kernels with & without this patch. A
variant of maltasmvp_defconfig with CONFIG_CPU_MIPS32_R6 selected is
also shown, to demonstrate that MIPSr6 systems benefit more due to extra
features becoming required by that architecture revision. Builds of
pistachio_defconfig are also shown, as although this is a MIPSr2
platform it doesn't hardcode any features in a machine-specific
cpu-feature-overrides.h, which allows it to gain more from this patch
than the equivalent Malta r2 build.
MIPS: jz4780: DTS: Probe the spi-gpio driver from devicetree
Make use of the spi-gpio driver to provide SPI support on the Ingenic
JZ4780 SoC using the pins that can be used with the SSI0 device as
GPIOs, until such time as we have support for the Ingenic SPI/SSI
controller.
[paul.burton@mips.com: Rewrite commit message.]
Signed-off-by: Mathieu Malaterre <malat@debian.org> Signed-off-by: Paul Burton <paul.burton@mips.com>
Patchwork: https://patchwork.linux-mips.org/patch/19489/ Cc: James Hogan <jhogan@kernel.org> Cc: Rob Herring <robh+dt@kernel.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: devicetree@vger.kernel.org Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org
Thomas Petazzoni [Tue, 24 Jul 2018 11:52:08 +0000 (13:52 +0200)]
mips: use asm-generic version of msi.h
This is necessary to be able to include <linux/msi.h> when
CONFIG_GENERIC_MSI_IRQ_DOMAIN is enabled. Without this, a build with
CONFIG_GENERIC_MSI_IRQ_DOMAIN fails with:
In file included from include/linux/kvm_host.h:20:0,
from arch/mips/kernel/asm-offsets.c:24:
>> include/linux/msi.h:197:10: fatal error: asm/msi.h: No such file or directory
#include <asm/msi.h>
^~~~~~~~~~~
compilation terminated.
make[2]: *** [arch/mips/kernel/asm-offsets.s] Error 1
make[2]: Target '__build' not remade because of errors.
make[1]: *** [prepare0] Error 2
make[1]: Target 'prepare' not remade because of errors.
make: *** [sub-make] Error 2
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com> Signed-off-by: Paul Burton <paul.burton@mips.com>
Patchwork: https://patchwork.linux-mips.org/patch/19986/ Cc: Ralf Baechle <ralf@linux-mips.org> Cc: James Hogan <jhogan@kernel.org> Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Cc: Marc Zyngier <marc.zyngier@arm.com> Cc: Hanna Hawa <hannah@marvell.com>
Paul Cercueil [Sun, 8 Jul 2018 15:07:12 +0000 (17:07 +0200)]
MIPS: jz4740: Bump zload address
Having the zload address at 0x8060.0000 means the size of the
uncompressed kernel cannot be bigger than around 6 MiB, as it is
deflated at address 0x8001.0000.
This limit is too small; a kernel with some built-in drivers and things
like debugfs enabled will already be over 6 MiB in size, and so will
fail to extract properly.
To fix this, we bump the zload address from 0x8060.0000 to 0x8100.0000.
This is fine, as all the boards featuring Ingenic JZ SoCs have at least
32 MiB of RAM, and use u-boot or compatible bootloaders which won't
hardcode the load address but read it from the uImage's header.
Signed-off-by: Paul Cercueil <paul@crapouillou.net> Signed-off-by: Paul Burton <paul.burton@mips.com>
Patchwork: https://patchwork.linux-mips.org/patch/19787/ Cc: Ralf Baechle <ralf@linux-mips.org> Cc: James Hogan <jhogan@kernel.org> Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org
MIPS: Change definition of cpu_relax() for Loongson-3
Linux expects that if a CPU modifies a memory location, then that
modification will eventually become visible to other CPUs in the system.
Loongson 3 CPUs include a Store Fill Buffer (SFB) which sits between a
core & its L1 data cache, queueing memory accesses & allowing for faster
forwarding of data from pending stores to younger loads from the core.
Unfortunately the SFB prioritizes loads such that a continuous stream of
loads may cause a pending write to be buffered indefinitely. This is
problematic if we end up with 2 CPUs which each perform a store that the
other polls for - one or both CPUs may end up with their stores buffered
in the SFB, never reaching cache due to the continuous reads from the
poll loop. Such a deadlock condition has been observed whilst running
qspinlock code.
This patch changes the definition of cpu_relax() to smp_mb() for
Loongson-3, forcing a flush of the SFB on SMP systems which will cause
any pending writes to make it as far as the L1 caches where they will
become visible to other CPUs. If the kernel is not compiled for SMP
support, this will expand to a barrier() as before.
This workaround matches that currently implemented for ARM when
CONFIG_ARM_ERRATA_754327=y, which was introduced by commit 534be1d5a2da
("ARM: 6194/1: change definition of cpu_relax() for ARM11MPCore").
Although the workaround is only required when the Loongson 3 SFB
functionality is enabled, and we only began explicitly enabling that
functionality in v4.7 with commit 1e820da3c9af ("MIPS: Loongson-3:
Introduce CONFIG_LOONGSON3_ENHANCEMENT"), existing or future firmware
may enable the SFB which means we may need the workaround backported to
earlier kernels too.
[paul.burton@mips.com:
- Reword commit message & comment.
- Limit stable backport to v3.15+ where we support Loongson 3 CPUs.]
This macro substitution is the shortcut to map cacheable IO memory
with coherent and write-back attributes. Since it is entirely unused
by kernel, lets just remove it.
Signed-off-by: Serge Semin <fancer.lancer@gmail.com> Signed-off-by: Paul Burton <paul.burton@mips.com> Suggested-by: Christoph Hellwig <hch@infradead.org>
Patchwork: https://patchwork.linux-mips.org/patch/19937/ CC: Paul Burton <paul.burton@mips.com> Cc: James Hogan <jhogan@kernel.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Sinan Kaya <okaya@codeaurora.org> Cc: Huacai Chen <chenhc@lemote.com> Cc: Sergey.Semin@t-platforms.ru Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org
Define an NT_MIPS_FP_MODE core file note and implement a corresponding
regset holding the state handled by PR_SET_FP_MODE and PR_GET_FP_MODE
prctl(2) requests. This lets debug software correctly interpret the
contents of floating-point general registers both in live debugging and
in core files, and also switch floating-point modes of a live process.
[paul.burton@mips.com:
- Changed NT_MIPS_FP_MODE to 0x801 to match first nibble of
NT_MIPS_DSP, which was also changed to avoid a conflict.]
Signed-off-by: Maciej W. Rozycki <macro@mips.com> Signed-off-by: Paul Burton <paul.burton@mips.com>
Patchwork: https://patchwork.linux-mips.org/patch/19331/ Cc: James Hogan <jhogan@kernel.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org
Define an NT_MIPS_DSP core file note type and implement a corresponding
regset holding the DSP ASE register context, following the layout of the
`mips_dsp_state' structure, except for the DSPControl register stored as
a 64-bit rather than 32-bit quantity in a 64-bit note.
The lack of DSP ASE register saving to core files can be considered a
design flaw with commit e50c0a8fa60d ("Support the MIPS32 / MIPS64 DSP
ASE."), leading to an incomplete state being saved. Consequently no DSP
ASE regset has been created with commit 7aeb753b5353 ("MIPS: Implement
task_user_regset_view."), when regset support was added to the MIPS
port.
Additionally there is no way for ptrace(2) to correctly access the DSP
accumulator registers in n32 processes with the existing interfaces.
This is due to 32-bit truncation of data passed with PTRACE_PEEKUSR and
PTRACE_POKEUSR requests, which cannot be avoided owing to how the data
types for ptrace(3) have been defined. This new NT_MIPS_DSP regset
fills the missing interface gap.
[paul.burton@mips.com:
- Change NT_MIPS_DSP to 0x800 to avoid conflict with NT_VMCOREDD
introduced by commit 2724273e8fd0 ("vmcore: add API to collect
hardware dump in second kernel").
- Drop stable tag. Whilst I agree the lack of this functionality can
be considered a flaw in earlier DSP ASE support, it's still new
functionality which doesn't meet up to the requirements set out in
Documentation/process/stable-kernel-rules.rst.]
Signed-off-by: Maciej W. Rozycki <macro@mips.com> Signed-off-by: Paul Burton <paul.burton@mips.com>
References: 7aeb753b5353 ("MIPS: Implement task_user_regset_view.")
Patchwork: https://patchwork.linux-mips.org/patch/19330/ Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: James Hogan <jhogan@kernel.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-fsdevel@vger.kernel.org Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org
MIPS: Correct the 64-bit DSP accumulator register size
Use the `unsigned long' rather than `__u32' type for DSP accumulator
registers, like with the regular MIPS multiply/divide accumulator and
general-purpose registers, as all are 64-bit in 64-bit implementations
and using a 32-bit data type leads to contents truncation on context
saving.
Update `arch_ptrace' and `compat_arch_ptrace' accordingly, removing
casts that are similarly not used with multiply/divide accumulator or
general-purpose register accesses.
Signed-off-by: Maciej W. Rozycki <macro@mips.com> Signed-off-by: Paul Burton <paul.burton@mips.com> Fixes: e50c0a8fa60d ("Support the MIPS32 / MIPS64 DSP ASE.")
Patchwork: https://patchwork.linux-mips.org/patch/19329/ Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: James Hogan <jhogan@kernel.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-fsdevel@vger.kernel.org Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Cc: stable@vger.kernel.org # 2.6.15+
binfmt_elf: Respect error return from `regset->active'
The regset API documented in <linux/regset.h> defines -ENODEV as the
result of the `->active' handler to be used where the feature requested
is not available on the hardware found. However code handling core file
note generation in `fill_thread_core_info' interpretes any non-zero
result from the `->active' handler as the regset requested being active.
Consequently processing continues (and hopefully gracefully fails later
on) rather than being abandoned right away for the regset requested.
Fix the problem then by making the code proceed only if a positive
result is returned from the `->active' handler.
Signed-off-by: Maciej W. Rozycki <macro@mips.com> Signed-off-by: Paul Burton <paul.burton@mips.com> Fixes: 4206d3aa1978 ("elf core dump: notes user_regset")
Patchwork: https://patchwork.linux-mips.org/patch/19332/ Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: James Hogan <jhogan@kernel.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-fsdevel@vger.kernel.org Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org
prom_putchar() is used centrally in early printk infrastructure therefore
at least MIPS should agree on the function return type.
[paul.burton@mips.com:
- Include linux/types.h in asm/setup.h to gain the bool typedef before
we start include asm/setup.h elsewhere.
- Include asm/setup.h in all files that use or define prom_putchar().
- Also standardise on signed rather than unsigned char argument.]
Signed-off-by: Alexander Sverdlin <alexander.sverdlin@nokia.com> Signed-off-by: Paul Burton <paul.burton@mips.com>
Patchwork: https://patchwork.linux-mips.org/patch/19842/ Cc: linux-mips@linux-mips.org Cc: Ralf Baechle <ralf@linux-mips.org> Cc: James Hogan <jhogan@kernel.org> Cc: Jonas Gorski <jonas.gorski@gmail.com> Cc: Florian Fainelli <f.fainelli@gmail.com> Cc: Kate Stewart <kstewart@linuxfoundation.org> Cc: Philippe Ombredanne <pombredanne@nexb.com>
Joshua Kinard [Sun, 19 Nov 2017 04:00:51 +0000 (23:00 -0500)]
MIPS: Cleanup R10000_LLSC_WAR logic in atomic.h
This patch reduces down the conditionals in MIPS atomic code that deal
with a silicon bug in early R10000 cpus that required a workaround of
a branch-likely instruction following a store-conditional in order to
to guarantee the whole ll/sc sequence is atomic. As the only real
difference is a branch-likely instruction (beqzl) over a standard
branch (beqz), the conditional is reduced down to a single preprocessor
check at the top to pick the required instruction.
This requires writing the uses in assembler, thus we discard the
non-R10000 case that uses a mixture of a C do...while loop with
embedded assembler that was added back in commit 7837314d141c ("MIPS:
Get rid of branches to .subsections."). A note found in the git log
for commit 5999eca25c1f ("[MIPS] Improve branch prediction in ll/sc
atomic operations.") is also addressed.
The macro definition for the branch instruction and the code comment
derives from a patch sent in earlier by Paul Burton for various cmpxchg
cleanups.
[paul.burton@mips.com:
- Minor whitespace fix for checkpatch.]
Signed-off-by: Joshua Kinard <kumba@gentoo.org> Signed-off-by: Paul Burton <paul.burton@mips.com>
Patchwork: https://patchwork.linux-mips.org/patch/17736/ Cc: Ralf Baechle <ralf@linux-mips.org> Cc: James Hogan <james.hogan@mips.com> Cc: "Maciej W. Rozycki" <macro@mips.com> Cc: linux-mips@linux-mips.org
Joshua Kinard [Sun, 19 Nov 2017 03:29:56 +0000 (22:29 -0500)]
MIPS: Fix delay slot bug in `atomic*_sub_if_positive' for R10000_LLSC_WAR
This patch fixes an old bug in MIPS ll/sc atomics, in the
`atomic_sub_if_positive' and `atomic64_sub_if_positive' functions, for
the R10000_LLSC_WAR case where the result of the subu/dsubu instruction
would potentially not be made available to the sc/scd instruction due
to being in the delay-slot of the branch-likely (beqzl) instruction.
This also removes the need for the `noreorder' directive, allowing GAS
to use delay slot scheduling as needed.
The same fix is also applied to the standard branch (beqz) case in
preparation for a follow-up patch that will cleanup/merge the
R10000_LLSC_WAR and non-R10K sections together.
Signed-off-by: Joshua Kinard <kumba@gentoo.org> Signed-off-by: Paul Burton <paul.burton@mips.com> Tested-by: Joshua Kinard <kumba@gentoo.org>
Patchwork: https://patchwork.linux-mips.org/patch/17735/ Cc: Ralf Baechle <ralf@linux-mips.org> Cc: James Hogan <james.hogan@mips.com> Cc: "Maciej W. Rozycki" <macro@mips.com> Cc: linux-mips@linux-mips.org
mips/jazz: provide missing dma_mask/coherent_dma_mask
Commit 205e1b7f51e4 ("dma-mapping: warn when there is no
coherent_dma_mask") introduced a warning, if a device is missing a
coherent_dma_mask. ESP and sonic are using dma mapping functions, so
they need dma masks.
[paul.burton@mips.com:
- Wrap commit message.]
Signed-off-by: Thomas Bogendoerfer <tbogendoerfer@suse.de> Signed-off-by: Paul Burton <paul.burton@mips.com>
Patchwork: https://patchwork.linux-mips.org/patch/19828/ Cc: Ralf Baechle <ralf@linux-mips.org> Cc: James Hogan <jhogan@kernel.org> Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org
Adaptive ioremap_wc() method is now available as of commit 9748e33e26c6
("mips: mm: Create UCA-based ioremap_wc() method"). We can use it to
obtain UnCached Accelerated (UCA) mappings safely on all MIPS systems,
and so we don't need the MIPS-specific ioremap_uncached_accelerated()
any longer. This macro hard-coded the UCA Cache Coherency Attribute
(CCA) in a manner that isn't safe for kernels that may run on different
CPUs, and it is also entirely unused so we can trivially remove it.
[paul.burton@mips.com:
- Reword the commit message a little.
- Remove CC stable.]
Modern MIPS cores (like P5600/6600, M5150/6520, end so on) which
got L2-cache on chip also can enable a special type Cache-Coherency
attribute (CCA) named UnCached Accelerated attribute (UCA). In this
way uncached accelerated accesses are treated the same way as
non-accelerated uncached accesses, but uncached stores are gathered
together for more efficient bus utilization. So to speak this CCA
enables uncached transactions to better utilize bus bandwidth via
burst transactions.
This is exactly why ioremap_wc() method has been introduced in Linux.
Alas MIPS-platform code hasn't implemented it so far, instead default
one has been used which was an alias to ioremap_nocache. In order to
fix this we added MIPS-specific ioremap_wc() macro substituted by
generic __ioremap_mode() method call with writecombine CPU-info
field passed. It shall create real ioremap_wc() method if CPU-cache
supports UCA feature and fall-back to _CACHE_UNCACHED attribute
if one doesn't. Additionally platform-specific io.h shall declare
ARCH_HAS_IOREMAP_WC macro as indication of architectural definition
of ioremap_wc() (similar to x86/powerpc).
[paul.burton@mips.com:
- Remove CC stable, this is new functionality.]
Steven J. Hill [Tue, 3 Jul 2018 21:44:25 +0000 (16:44 -0500)]
MIPS: Octeon: Simplify CIU register functions.
Collapse and simplify switch statements in functions.
Signed-off-by: Steven J. Hill <steven.hill@cavium.com> Signed-off-by: Paul Burton <paul.burton@mips.com>
Patchwork: https://patchwork.linux-mips.org/patch/19713/ Cc: linux-mips@linux-mips.org Cc: Chandrakala Chavva <cchavva@caviumnetworks.com>
Steven J. Hill [Tue, 3 Jul 2018 21:44:24 +0000 (16:44 -0500)]
MIPS: Octeon: Create simple macro for CIU registers.
Create new CVMX_CIU_ADDR macro to improve readability.
Signed-off-by: Steven J. Hill <steven.hill@cavium.com> Signed-off-by: Paul Burton <paul.burton@mips.com>
Patchwork: https://patchwork.linux-mips.org/patch/19712/ Cc: linux-mips@linux-mips.org Cc: Chandrakala Chavva <cchavva@caviumnetworks.com>
Steven J. Hill [Tue, 3 Jul 2018 21:44:23 +0000 (16:44 -0500)]
MIPS: Octeon: Remove all unused CIU macros.
Get rid of all unused CIU macros and sort them. Verified with
'make allyesconfig' build test.
[paul.burton@mips.com:
- Also checked via convoluted grep invocation for use of all removed
macros within arch/mips/ & drivers/.]
Signed-off-by: Steven J. Hill <steven.hill@cavium.com> Signed-off-by: Paul Burton <paul.burton@mips.com>
Patchwork: https://patchwork.linux-mips.org/patch/19710/ Cc: linux-mips@linux-mips.org Cc: Chandrakala Chavva <cchavva@caviumnetworks.com>
Steven J. Hill [Tue, 3 Jul 2018 21:44:22 +0000 (16:44 -0500)]
MIPS: Octeon: Convert CIU types to use bitfields.
Convert remaining structures to use __BITFIELD_FIELD macro. Also
straighten up the description text and whitespace.
Signed-off-by: Steven J. Hill <steven.hill@cavium.com> Signed-off-by: Paul Burton <paul.burton@mips.com>
Patchwork: https://patchwork.linux-mips.org/patch/19709/ Cc: linux-mips@linux-mips.org Cc: Chandrakala Chavva <cchavva@caviumnetworks.com>
Steven J. Hill [Tue, 3 Jul 2018 21:44:21 +0000 (16:44 -0500)]
MIPS: Octeon: Unify QLM data types in CIU header.
Data types 'cvmx_ciu_qlm0' and 'cvmx_ciu_qlm1' are identical in
their usage and structure. Combine them and update the PCIe code.
Signed-off-by: Steven J. Hill <steven.hill@cavium.com> Signed-off-by: Paul Burton <paul.burton@mips.com>
Patchwork: https://patchwork.linux-mips.org/patch/19708/ Cc: linux-mips@linux-mips.org Cc: Chandrakala Chavva <cchavva@caviumnetworks.com>
Steven J. Hill [Tue, 3 Jul 2018 21:44:20 +0000 (16:44 -0500)]
MIPS: Octeon: Remove unused CIU types.
Remove all unused data types. Verified with a 'make allyesconfig'
and Cavium platform.
[paul.burton@mips.com:
- Also checked via convoluted grep invocation for use of all removed
structs & unions within arch/mips/ & drivers/.]
Signed-off-by: Steven J. Hill <steven.hill@cavium.com> Signed-off-by: Paul Burton <paul.burton@mips.com>
Patchwork: https://patchwork.linux-mips.org/patch/19711/ Cc: linux-mips@linux-mips.org Cc: Chandrakala Chavva <cchavva@caviumnetworks.com>
Coldfire still provides its own variant of the clk API rather than using
the generic COMMON_CLK API. This generally works, but it causes some
link errors with drivers using the clk_round_rate(), clk_set_rate(),
clk_set_parent(), or clk_get_parent() functions when a platform lacks
those interfaces.
This adds empty stub implementations for each of them, and I don't even
try to do something useful here but instead just print a WARN() message
to make it obvious what is going on if they ever end up being called.
The drivers that call these won't be used on these platforms (otherwise
we'd get a link error today), so the added code is harmless bloat and
will warn about accidental use.
Based on commit bd7fefe1f06ca6cc ("ARM: w90x900: normalize clk API").
Paul Burton [Tue, 19 Jun 2018 00:37:59 +0000 (17:37 -0700)]
MIPS: Always use -march=<arch>, not -<arch> shortcuts
The VDSO Makefile filters CFLAGS to select a subset which it uses whilst
building the VDSO ELF. One of the flags it allows through is the -march=
flag that selects the architecture/ISA to target.
Unfortunately in cases where CONFIG_CPU_MIPS32_R{1,2}=y and the
toolchain defaults to building for MIPS64, the main MIPS Makefile ends
up using the short-form -<arch> flags in cflags-y. This is because the
calls to cc-option always fail to use the long-form -march=<arch> flag
due to the lack of an -mabi=<abi> flag in KBUILD_CFLAGS at the point
where the cc-option function is executed. The resulting GCC invocation
is something like:
$ mips64-linux-gcc -Werror -march=mips32r2 -c -x c /dev/null -o tmp
cc1: error: '-march=mips32r2' is not compatible with the selected ABI
These short-form -<arch> flags are dropped by the VDSO Makefile's
filtering, and so we attempt to build the VDSO without specifying any
architecture. This results in an attempt to build the VDSO using
whatever the compiler's default architecture is, regardless of whether
that is suitable for the kernel configuration.
One encountered build failure resulting from this mismatch is a
rejection of the sync instruction if the kernel is configured for a
MIPS32 or MIPS64 r1 or r2 target but the toolchain defaults to an older
architecture revision such as MIPS1 which did not include the sync
instruction:
CC arch/mips/vdso/gettimeofday.o
/tmp/ccGQKoOj.s: Assembler messages:
/tmp/ccGQKoOj.s:273: Error: opcode not supported on this processor: mips1 (mips1) `sync'
/tmp/ccGQKoOj.s:329: Error: opcode not supported on this processor: mips1 (mips1) `sync'
/tmp/ccGQKoOj.s:520: Error: opcode not supported on this processor: mips1 (mips1) `sync'
/tmp/ccGQKoOj.s:714: Error: opcode not supported on this processor: mips1 (mips1) `sync'
/tmp/ccGQKoOj.s:1009: Error: opcode not supported on this processor: mips1 (mips1) `sync'
/tmp/ccGQKoOj.s:1066: Error: opcode not supported on this processor: mips1 (mips1) `sync'
/tmp/ccGQKoOj.s:1114: Error: opcode not supported on this processor: mips1 (mips1) `sync'
/tmp/ccGQKoOj.s:1279: Error: opcode not supported on this processor: mips1 (mips1) `sync'
/tmp/ccGQKoOj.s:1334: Error: opcode not supported on this processor: mips1 (mips1) `sync'
/tmp/ccGQKoOj.s:1374: Error: opcode not supported on this processor: mips1 (mips1) `sync'
/tmp/ccGQKoOj.s:1459: Error: opcode not supported on this processor: mips1 (mips1) `sync'
/tmp/ccGQKoOj.s:1514: Error: opcode not supported on this processor: mips1 (mips1) `sync'
/tmp/ccGQKoOj.s:1814: Error: opcode not supported on this processor: mips1 (mips1) `sync'
/tmp/ccGQKoOj.s:2002: Error: opcode not supported on this processor: mips1 (mips1) `sync'
/tmp/ccGQKoOj.s:2066: Error: opcode not supported on this processor: mips1 (mips1) `sync'
make[2]: *** [scripts/Makefile.build:318: arch/mips/vdso/gettimeofday.o] Error 1
make[1]: *** [scripts/Makefile.build:558: arch/mips/vdso] Error 2
make[1]: *** Waiting for unfinished jobs....
This can be reproduced for example by attempting to build
pistachio_defconfig using Arnd's GCC 8.1.0 mips64 toolchain from
kernel.org:
Resolve this problem by using the long-form -march=<arch> in all cases,
which makes it through the arch/mips/vdso/Makefile's filtering & is thus
consistently used to build both the kernel proper & the VDSO.
The use of cc-option to prefer the long-form & fall back to the
short-form flags makes no sense since the short-form is just an
abbreviation for the also-supported long-form in all GCC versions that
we support building with. This means there is no case in which we have
to use the short-form -<arch> flags, so we can simply remove them.
The manual redefinition of _MIPS_ISA is removed naturally along with the
use of the short-form flags that it accompanied, and whilst here we
remove the separate assembler ISA selection. I suspect that both of
these were only required due to the mips32 vs mips2 mismatch that was
introduced by commit 59b3e8e9aac6 ("[MIPS] Makefile crapectomy.") and
fixed but not cleaned up by commit 9200c0b2a07c ("[MIPS] Fix Makefile
bugs for MIPS32/MIPS64 R1 and R2.").
I've marked this for backport as far as v4.4 where the MIPS VDSO was
introduced. In earlier kernels there should be no ill effect to using
the short-form flags.
Signed-off-by: Paul Burton <paul.burton@mips.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Cc: stable@vger.kernel.org # v4.4+ Reviewed-by: James Hogan <jhogan@kernel.org>
Patchwork: https://patchwork.linux-mips.org/patch/19579/
Paul Burton [Fri, 22 Jun 2018 17:55:47 +0000 (10:55 -0700)]
MIPS: Annotate cpu_wait implementations with __cpuidle
Annotate cpu_wait implementations using the __cpuidle macro which
places these functions in the .cpuidle.text section. This allows
cpu_in_idle() to return true for PC values which fall within these
functions, allowing nmi_backtrace() to produce cleaner output for CPUs
running idle functions. For example:
Without this we get register value & backtrace output from all CPUs,
which is generally useless for those running the idle function & serves
only to overwhelm & obfuscate the meaningful output from non-idle CPUs.
Signed-off-by: Paul Burton <paul.burton@mips.com> Cc: James Hogan <jhogan@kernel.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Huacai Chen <chenhc@lemote.com> Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/19598/
Paul Burton [Mon, 19 Sep 2016 21:21:31 +0000 (22:21 +0100)]
MIPS: Malta: Use PIIX4 poweroff driver to power down
Remove the platform code used to power down the system, instead relying
upon the new PIIX4 poweroff driver. This reduces the amount of platform
code required for the Malta board in preparation for allowing it to be
part of a more generic kernel.
Signed-off-by: Paul Burton <paul.burton@mips.com>
Patchwork: https://patchwork.linux-mips.org/patch/14282/
Paul Burton [Fri, 2 Sep 2016 15:10:06 +0000 (16:10 +0100)]
MIPS: Malta: Cleanup DMA coherence #ifdefs
DMA coherence is not user-selectable in Kconfig, and Malta selects
CONFIG_DMA_MAYBE_COHERENT which in turn selects CONFIG_DMA_NONCOHERENT.
Remove #ifdefs whose conditions can therefore never be true for Malta.
This removes a significant amount of code from bonito_quirks_setup(),
but the code is duplicated in plat_enable_iocoherency() anyway so we
lose nothing but duplication.
Signed-off-by: Paul Burton <paul.burton@mips.com>
Patchwork: https://patchwork.linux-mips.org/patch/14188/
Paul Burton [Fri, 2 Jun 2017 22:17:25 +0000 (15:17 -0700)]
MIPS: Set MIPS_IC_SNOOPS_REMOTE for systems with CM
In systems that include a MIPS Coherency Manager, the icache always
fills from a cache which is coherent across all CPUs. In I6400 & I6500
systems the icache fills from the dcache which is coherent across all
CPUs. In all other CM-based systems the icache fills from the L2 cache
which is shared between all cores.
This means that an icache will always see stores from remote CPUs
without needing to write them back any further than that L2, which is
what the cpu_icache_snoops_remote_store feature is used to test. In
order for it to return 1 without needing a per-platform override (which
is what Malta has relied upon so far) set the MIPS_IC_SNOOPS_REMOTE flag
when a CM is present.
Joshua Kinard [Tue, 17 Oct 2017 18:26:12 +0000 (14:26 -0400)]
MIPS: Use !pci_is_root_bus(bus) in ops-bridge.c
This is a manual cherrypick of commit c7ddc3d137b7 from Alastair
Bridgewater's IP35 tree that replaces two cases of
"if (bus->number > 0)" with a more correct "if (!pci_is_root_bus(bus))"
in arch/mips/pci/ops-bridge.c.
Paul Burton [Tue, 19 Dec 2017 23:11:08 +0000 (15:11 -0800)]
MIPS: Schedule on CPUs we need to lose FPU for a mode switch
Commit 6b8322576e9d ("MIPS: Force CPUs to lose FP context during mode
switches") ensures that we react to PR_SET_FP_MODE prctl syscalls
quickly by broadcasting an IPI in order to cause CPUs to lose FPU access
when necessary. Whilst it achieves that, unfortunately it causes all
sorts of strange race conditions because:
1) The IPI may arrive at a point where the FPU is in the process of
being enabled, but that process is not yet complete leading to a
state we aren't prepared to handle. For example:
2) The IPI may arrive during kernel use of the FPU, since we generally
only disable preemption around use of the FPU & leave interrupts
enabled. This can lead to us unexpectedly losing access to the FPU
in places where it previously had not been possible. For example:
At first glance a simple fix may seem to be to disable interrupts around
kernel use of the FPU rather than merely preemption, however this would
introduce further overhead outside of the mode switch path & doesn't
solve the third problem:
3) The IPI may arrive whilst the kernel is running code that will lead
to a preempt_disable() call & FPU usage soon. If this happens then
the IPI will be serviced & we'll proceed to enable an FPU whilst the
mode switch is in progress, leading to strange & inconsistent
behaviour.
Further to all of this is a separate but related problem:
4) There are various paths through which we may enable the FPU without
the user having triggered a coprocessor 1 disabled exception. These
paths are those in which we emulate instructions & then enable the
FPU with the expectation that the user might execute an FP
instruction shortly afterwards. However these paths have not
previously checked whether an FP mode switch is underway for the
task, and therefore could enable the FPU whilst such a mode switch
is in progress leading to strange & inconsistent behaviour for user
code.
This patch fixes all of the above by taking a step back & re-examining
our approach to FP mode switches. Up until now we have taken these basic
steps:
a) Prevent any threads that are part of the affected process from being
able to obtain ownership of the FPU.
b) Cause any threads that are part of the affected process and already
have ownership of an FPU to lose it.
c) Set the thread flags for each thread that is part of the affected
process to reflect the new FP mode.
d) Allow threads to obtain ownership of the FPU again.
This approach is however more complex than necessary. All that we really
require is that the mode switch has occurred for all threads that are
part of the affected process before mips_set_process_fp_mode(), and thus
the PR_SET_FP_MODE prctl() syscall, returns. This doesn't require that
we stop threads from owning or using an FPU whilst a mode switch occurs,
only that we force them to relinquish it after the mode switch has
occurred such that they next own an FPU with the correct mode
configured. Our basic steps therefore simplify to:
A) Set the thread flags for each thread that is part of the affected
process to reflect the new FP mode.
B) Cause any threads that are part of the affected process and already
have ownership of an FPU to lose it.
We implement B) by forcing each CPU which might be running a thread
which is part of the affected process to schedule a no-op function,
which causes the affected thread to lose its FPU ownership when it is
descheduled.
The end result is simpler FP mode switching with less overhead in the
FPU enable path (ie. enable_restore_fp_context()) and fewer moving
parts.
Signed-off-by: Paul Burton <paul.burton@mips.com> Fixes: 9791554b45a2 ("MIPS,prctl: add PR_[GS]ET_FP_MODE prctl options for MIPS") Fixes: 6b8322576e9d ("MIPS: Force CPUs to lose FP context during mode switches") Cc: James Hogan <jhogan@kernel.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Cc: stable <stable@vger.kernel.org> # v4.0+
The DT core will call of_platform_default_populate, so it is not necessary
for arch specific code to call it unless there are custom match entries,
auxdata or parent device. Neither of those apply here, so remove the call.
Cc: John Crispin <john@phrozen.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul Burton <paul.burton@mips.com> Cc: James Hogan <jhogan@kernel.org> Cc: linux-mips@linux-mips.org Signed-off-by: Rob Herring <robh@kernel.org>
Patchwork: https://patchwork.linux-mips.org/patch/19592/ Signed-off-by: Paul Burton <paul.burton@mips.com> Cc: linux-kernel@vger.kernel.org
The DT core will call of_platform_populate, so it is not necessary for
arch specific code to call it unless there are custom match entries,
auxdata or parent device. Neither of those apply here, so remove the call.
Cc: Paul Burton <paul.burton@mips.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: James Hogan <jhogan@kernel.org> Cc: linux-mips@linux-mips.org Signed-off-by: Rob Herring <robh@kernel.org>
Patchwork: https://patchwork.linux-mips.org/patch/19591/ Signed-off-by: Paul Burton <paul.burton@mips.com> Cc: linux-kernel@vger.kernel.org
Rob Herring [Tue, 19 Jun 2018 21:47:08 +0000 (15:47 -0600)]
MIPS: bmips: remove unnecessary call to register "simple-bus"
The DT core will register "simple-bus" by default, so it is not necessary
for arch specific code to do so unless there are custom match entries,
auxdata or parent device. Neither of those apply here, so remove the call.
Cc: Kevin Cernekee <cernekee@gmail.com> Cc: Florian Fainelli <f.fainelli@gmail.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul Burton <paul.burton@mips.com> Cc: James Hogan <jhogan@kernel.org> Cc: linux-mips@linux-mips.org Signed-off-by: Rob Herring <robh@kernel.org>
Patchwork: https://patchwork.linux-mips.org/patch/19590/ Signed-off-by: Paul Burton <paul.burton@mips.com> Cc: linux-kernel@vger.kernel.org
The DT core code will probe "simple-bus" by default, so remove
the Netlogic specific call. The probing of simple-bus happens at
arch_initcall_sync, so the call being removed here is already a nop.
Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul Burton <paul.burton@mips.com> Cc: James Hogan <jhogan@kernel.org> Cc: linux-mips@linux-mips.org Signed-off-by: Rob Herring <robh@kernel.org>
Patchwork: https://patchwork.linux-mips.org/patch/19589/ Signed-off-by: Paul Burton <paul.burton@mips.com> Cc: linux-kernel@vger.kernel.org
Rob Herring [Tue, 19 Jun 2018 21:47:06 +0000 (15:47 -0600)]
MIPS: octeon: use of_platform_populate to probe devices
of_platform_bus_probe is deprecated in favor of of_platform_populate.
of_platform_populate is stricter requiring compatible properties for
matching rather than name or type. Octeon uses compatible strings for
matching, so convert it to of_platform_populate.
Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul Burton <paul.burton@mips.com> Cc: James Hogan <jhogan@kernel.org> Cc: linux-mips@linux-mips.org Signed-off-by: Rob Herring <robh@kernel.org>
Patchwork: https://patchwork.linux-mips.org/patch/19588/ Signed-off-by: Paul Burton <paul.burton@mips.com> Cc: linux-kernel@vger.kernel.org
Heiher [Mon, 11 Jun 2018 09:01:10 +0000 (17:01 +0800)]
MIPS: Fix ejtag handler on SMP
On SMP systems, the shared ejtag debug buffer may be overwritten by
other cores, because every cores can generate ejtag exception at
same time.
Unfortunately, in that context, it's difficult to relax more registers
to access per cpu buffers. so use ll/sc to serialize the access.
[paul.burton@mips.com:
This could in theory be backported at least as far back as the
beginning of the git era, however in general it's exceedingly rare
that anyone would hit this without further changes, so it doesn't seem
worthwhile marking for backport.]
MIPS: boot: merge build rules of vmlinux.*.itb by using pattern rule
Merge the build rule of vmlinux.{gz,bz2,lzma,lzo}.itb, and also move
'targets' close to the related code.
[paul.burton@mips.com:
- Remove leading tabs from assignments to itb_addr_cells, since after
this patch moves the additions to the 'targets' variable the
assignments to itb_addr_cells wound up being treated as part of the
uImage rule above them, causing the .its to incorrectly be generated
with empty ADDR_CELLS.]
As Documentation/kbuild/makefile.txt says, it is a typical mistake
to forget the FORCE prerequisite for the rule invoked by if_changed.
Add the FORCE to the prerequisite, but it must be filtered-out from
the files passed to the 'cat' command. Because this rule generates
.vmlinux.its.S.cmd, vmlinux.its.S must be specified as targets so
that the .cmd file is included.
MIPS: boot: do not include $(cpp_flags) for preprocessing ITS
$(CPP) is used here to perform macro replacement in ITS. Do not
pass $(cpp_flags) because it pulls in more options for dependency
file generation etc. but none of which is necessary here. ITS files
do not include any header file, so $(call if_change,...) is enough.
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