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.
See this potential GCC fix for details:
https://gcc.gnu.org/ml/gcc-patches/2015-09/msg00360.html
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):
Initmem setup node 0 [mem 0x0000000080000000-0x000000009fffffff]
VPE topology {2,2} total 4
Primary instruction cache 64kB, VIPT, 4-way, linesize 32 bytes.
Primary data cache 64kB, 4-way, PIPT, no aliases, linesize 32 bytes
<AdEL exception here>
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 173a3efd3e
("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: 173a3efd3e ("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
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 28128c61e0 ("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.
[1] https://lists.01.org/pipermail/kbuild-all/2018-August/051175.html
Signed-off-by: Paul Burton <paul.burton@mips.com>
Reviewed-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Patchwork: https://patchwork.linux-mips.org/patch/20269/
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: James Hogan <jhogan@kernel.org>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-arch@vger.kernel.org
Cc: linux-kbuild@vger.kernel.org
Cc: linux-mips@linux-mips.org
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 a0a5ac3ce8 ("MIPS: Fix delay
slot bug in `atomic*_sub_if_positive' for R10000_LLSC_WAR") and commit
4936084c2e ("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: a0a5ac3ce8 ("MIPS: Fix delay slot bug in `atomic*_sub_if_positive' for R10000_LLSC_WAR")
Fixes: 4936084c2e ("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
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
86a1708a9d ("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():
u32 *p = (u32 *)msk_isa16_mode((ulong)handle_tlbl);
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.
Signed-off-by: Paul Burton <paul.burton@mips.com>
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
22823ab419 ("EXPORT_SYMBOL() for asm"), so move the export to follow
the function's (stub) definition.
Signed-off-by: Paul Burton <paul.burton@mips.com>
Commit 33679a5037 ("MIPS: uasm: Remove needless ISA abstraction")
removed use of the MIPS_ISA preprocessor macro, but left a couple of
unused definitions of it behind.
Remove the dead code.
Signed-off-by: Paul Burton <paul.burton@mips.com>
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
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.
Signed-off-by: Paul Burton <paul.burton@mips.com>
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.
Signed-off-by: Paul Burton <paul.burton@mips.com>
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.
Signed-off-by: Paul Burton <paul.burton@mips.com>
Commit c22c804310 ("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.
Signed-off-by: Paul Burton <paul.burton@mips.com>
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.
Signed-off-by: Paul Burton <paul.burton@mips.com>
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
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
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
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 f2d0b0d5c1 ("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
The A() & AA() macros have been unused since commit 05e4396651
("[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
The sys_32_mmap2 function has been unused since we started using syscall
wrappers in commit dbda6ac089 ("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
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.
[paul.burton@mips.com: Rewrite commit message.]
Signed-off-by: 谢致邦 (XIE Zhibang) <Yeking@Red54.com>
Signed-off-by: Paul Burton <paul.burton@mips.com>
Patchwork: https://patchwork.linux-mips.org/patch/14927/
Cc: linux-mips@linux-mips.org
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 344ebf0994 ("MIPS: Always use
-march=<arch>, not -<arch> shortcuts").]
Signed-off-by: 谢致邦 (XIE Zhibang) <Yeking@Red54.com>
Signed-off-by: Paul Burton <paul.burton@mips.com>
Patchwork: https://patchwork.linux-mips.org/patch/16155/
Cc: linux-mips@linux-mips.org
Cc: ralf@linux-mips.org
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:
add/remove: 4/1 grow/shrink: 345/13 up/down: 9017/-392 (8625)
Function old new delta
pcpu_setup_first_chunk 1444 1780 +336
pcpu_alloc_first_chunk 864 1136 +272
start_kernel 1064 1288 +224
initcall_blacklist 224 372 +148
try_fill_recv 2088 2184 +96
...
Total: Before=8457273, After=8465898, chg +0.10%
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
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
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>
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 ed3ce16c3d ("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: ed3ce16c3d ("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
The call to of_find_node_by_name returns a node pointer with refcount
incremented thus it must be explicitly decremented here after the last
usage.
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/19558/
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
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
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.
Signed-off-by: Paul Burton <paul.burton@mips.com>
Acked-by: Florian Fainelli <f.fainelli@gmail.com>
Patchwork: https://patchwork.linux-mips.org/patch/14623/
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
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
The RTC definitions were moved to the driver, remove them from the platform
header.
[paul.burton@mips.com:
- Also remove the unused tx4939_rtcptr which would use struct
tx4939_rtc_reg if it were ever expanded.]
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Paul Burton <paul.burton@mips.com>
Patchwork: https://patchwork.linux-mips.org/patch/20024/
Cc: James Hogan <jhogan@kernel.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-kernel@vger.kernel.org
Cc: linux-mips@linux-mips.org
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
This patch ensures, that the pinmux register is properly setup for the
boot console UART when early_printk is enabled.
[paul.burton@mips.com:
- s/poinmux/pinmux/
- s/uart/UART/
- Drop extraneous parentheses.]
Signed-off-by: Gabor Juhos <juhosg@openwrt.org>
Signed-off-by: John Crispin <john@phrozen.org>
Signed-off-by: Paul Burton <paul.burton@mips.com>
Cc: James Hogan <jhogan@kernel.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
This patch adds a few additional cpu feature overrides so that they do not
need to be probed at runtime.
Signed-off-by: Felix Fietkau <nbd@nbd.name>
Signed-off-by: John Crispin <john@phrozen.org>
Signed-off-by: Paul Burton <paul.burton@mips.com>
Patchwork: https://patchwork.linux-mips.org/patch/19914/
Cc: James Hogan <jhogan@kernel.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
This patch disables irq on reboot to fix hang issues that were observed
due to pending interrupts.
Signed-off-by: Felix Fietkau <nbd@nbd.name>
Signed-off-by: John Crispin <john@phrozen.org>
Signed-off-by: Paul Burton <paul.burton@mips.com>
Patchwork: https://patchwork.linux-mips.org/patch/19913/
Cc: James Hogan <jhogan@kernel.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
The pinmux on QCA SoCs is controlled by a single register. The
"pinctrl-single" driver can be used but requires the target
to select PINCTRL.
Signed-off-by: John Crispin <john@phrozen.org>
Signed-off-by: Paul Burton <paul.burton@mips.com>
Patchwork: https://patchwork.linux-mips.org/patch/19909/
Cc: James Hogan <jhogan@kernel.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
This patch adds support for 2 new types of QCA silicon. TP9343 is
essentially the same as the QCA956X but is licensed by TPLink.
Signed-off-by: Weijie Gao <hackpascal@gmail.com>
Signed-off-by: Matthias Schiffer <mschiffer@universe-factory.net>
Signed-off-by: John Crispin <john@phrozen.org>
Signed-off-by: Paul Burton <paul.burton@mips.com>
Patchwork: https://patchwork.linux-mips.org/patch/19911/
Cc: James Hogan <jhogan@kernel.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
This patch adds many new registers for various QCA MIPS SoCs. The patch is
an aggragate of many contributions made to OpenWrt.
Signed-off-by: Gabor Juhos <juhosg@openwrt.org>
Signed-off-by: Henryk Heisig <hyniu@o2.pl>
Signed-off-by: Matthias Schiffer <mschiffer@universe-factory.net>
Signed-off-by: Weijie Gao <hackpascal@gmail.com>
Signed-off-by: Felix Fietkau <nbd@nbd.name>
Signed-off-by: Julien Dusser <julien.dusser@free.fr>
Signed-off-by: John Crispin <john@phrozen.org>
Signed-off-by: Paul Burton <paul.burton@mips.com>
Patchwork: https://patchwork.linux-mips.org/patch/19910/
Cc: James Hogan <jhogan@kernel.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Ocelot now has a u-boot port, allow building FIT images instead of relying
on the legacy detection and builtin DTB.
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Reviewed-by: James Hogan <jhogan@kernel.org>
Signed-off-by: Paul Burton <paul.burton@mips.com>
Patchwork: https://patchwork.linux-mips.org/patch/19632/
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
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
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>
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;
pr_info("\n\n\nTesting clear_user\n");
for (j = 0; j < 512; j++) {
if ((k = clear_user(NULL+3, j)) != j) {
pr_err("clear_user (NULL %d) returned %d\n", j, k);
}
}
return 0;
}
late_initcall(test_clear_user);
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);
for (j = 256; j < 512; j++) {
if ((k = clear_user(test + PAGE_SIZE - 254, j)) != j - 254) {
pr_err("clear_user (%px %d) returned %d\n",
test + PAGE_SIZE - 254, j, k);
}
}
return 0;
}
late_initcall(test_clear_user);
[ 3.976775] clear_user (c00000000000df02 256) returned 4
[ 3.981957] clear_user (c00000000000df02 257) returned 6
[ 3.986425] clear_user (c00000000000df02 258) returned 8
[ 3.990850] clear_user (c00000000000df02 259) returned 10
[ 3.995332] clear_user (c00000000000df02 260) returned 12
[ 3.999815] clear_user (c00000000000df02 261) returned 14
Fix this by ensuring that a2 is set to 0 during the set of final
unaligned bytes.
Signed-off-by: Matt Redfearn <matt.redfearn@mips.com>
Signed-off-by: Paul Burton <paul.burton@mips.com>
Fixes: 8c56208aff ("MIPS: lib: memset: Add MIPS R6 support")
Patchwork: https://patchwork.linux-mips.org/patch/19338/
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
Cc: stable@vger.kernel.org # v4.0+
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.
Config | Before | After | Change
----------------|---------|---------|---------
maltasmvp | 7248316 | 7247714 | -602
maltasmvp + r6 | 6955595 | 6950777 | -4818
pistachio | 8650977 | 8363898 | -287079
Signed-off-by: Paul Burton <paul.burton@mips.com>
Patchwork: https://patchwork.linux-mips.org/patch/16360/
Cc: Joshua Kinard <kumba@gentoo.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
