This reverts commit 920a42d8b8 which is
commit commit ed914d48b6 upstream.
Commit b2b29d6d01 (mm: account PMD tables like PTE tables) is
introduced between v5.9 and v5.10, so this fix (commit 002d8b395f)
should NOT apply to any pre-5.10 branch.
Signed-off-by: Huang Pei <huangpei@loongson.cn>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit ed914d48b6 ]
This fixes Page Table accounting bug.
MIPS is the ONLY arch just defining __HAVE_ARCH_PMD_ALLOC_ONE alone.
Since commit b2b29d6d01 (mm: account PMD tables like PTE tables),
"pmd_free" in asm-generic with PMD table accounting and "pmd_alloc_one"
in MIPS without PMD table accounting causes PageTable accounting number
negative, which read by global_zone_page_state(), always returns 0.
Signed-off-by: Huang Pei <huangpei@loongson.cn>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 33ae8f801a ]
If multiple threads are accessing the same huge page at the same
time, hugetlb_cow will be called if one thread write the COW huge
page. And function huge_ptep_clear_flush is called to notify other
threads to clear the huge pte tlb entry. The other threads clear
the huge pte tlb entry and reload it from page table, the reload
huge pte entry may be old.
This patch fixes this issue on mips platform, and it clears huge
pte entry before notifying other threads to flush current huge
page entry, it is similar with other architectures.
Signed-off-by: Bibo Mao <maobibo@loongson.cn>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 25ab14cbe9 upstream.
Remove the inline asm with a DIVU instruction from `__div64_32' and use
plain C code for the intended DIVMOD calculation instead. GCC is smart
enough to know that both the quotient and the remainder are calculated
with single DIVU, so with ISAs up to R5 the same instruction is actually
produced with overall similar code.
For R6 compiled code will work, but separate DIVU and MODU instructions
will be produced, which are also interlocked, so scalar implementations
will likely not perform as well as older ISAs with their asynchronous MD
unit. Likely still faster then the generic algorithm though.
This removes a compilation error for R6 however where the original DIVU
instruction is not supported anymore and the MDU accumulator registers
have been removed and consequently GCC complains as to a constraint it
cannot find a register for:
In file included from ./include/linux/math.h:5,
from ./include/linux/kernel.h:13,
from mm/page-writeback.c:15:
./include/linux/math64.h: In function 'div_u64_rem':
./arch/mips/include/asm/div64.h:76:17: error: inconsistent operand constraints in an 'asm'
76 | __asm__("divu $0, %z1, %z2" \
| ^~~~~~~
./include/asm-generic/div64.h:245:25: note: in expansion of macro '__div64_32'
245 | __rem = __div64_32(&(n), __base); \
| ^~~~~~~~~~
./include/linux/math64.h:91:22: note: in expansion of macro 'do_div'
91 | *remainder = do_div(dividend, divisor);
| ^~~~~~
This has passed correctness verification with test_div64 and reduced the
module's average execution time down to 1.0404s from 1.0445s with R3400
@40MHz. The module's MIPS I machine code has also shrunk by 12 bytes or
3 instructions.
Signed-off-by: Maciej W. Rozycki <macro@orcam.me.uk>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit c1d337d45e upstream.
We already check the high part of the divident against zero to avoid the
costly DIVU instruction in that case, needed to reduce the high part of
the divident, so we may well check against the divisor instead and set
the high part of the quotient to zero right away. We need to treat the
high part the divident in that case though as the remainder that would
be calculated by the DIVU instruction we avoided.
This has passed correctness verification with test_div64 and reduced the
module's average execution time down to 1.0445s and 0.2619s from 1.0668s
and 0.2629s respectively for an R3400 CPU @40MHz and a 5Kc CPU @160MHz.
Signed-off-by: Maciej W. Rozycki <macro@orcam.me.uk>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit c49f71f607 upstream.
Our current MIPS platform `__div64_32' handler is inactive, because it
is incorrectly only enabled for 64-bit configurations, for which generic
`do_div' code does not call it anyway.
The handler is not suitable for being called from there though as it
only calculates 32 bits of the quotient under the assumption the 64-bit
divident has been suitably reduced. Code for such reduction used to be
there, however it has been incorrectly removed with commit c21004cd5b
("MIPS: Rewrite <asm/div64.h> to work with gcc 4.4.0."), which should
have only updated an obsoleted constraint for an inline asm involving
$hi and $lo register outputs, while possibly wiring the original MIPS
variant of the `do_div' macro as `__div64_32' handler for the generic
`do_div' implementation
Correct the handler as follows then:
- Revert most of the commit referred, however retaining the current
formatting, except for the final two instructions of the inline asm
sequence, which the original commit missed. Omit the original 64-bit
parts though.
- Rename the original `do_div' macro to `__div64_32'. Use the combined
`x' constraint referring to the MD accumulator as a whole, replacing
the original individual `h' and `l' constraints used for $hi and $lo
registers respectively, of which `h' has been obsoleted with GCC 4.4.
Update surrounding code accordingly.
We have since removed support for GCC versions before 4.9, so no need
for a special arrangement here; GCC has supported the `x' constraint
since forever anyway, or at least going back to 1991.
- Rename the `__base' local variable in `__div64_32' to `__radix' to
avoid a conflict with a local variable in `do_div'.
- Actually enable this code for 32-bit rather than 64-bit configurations
by qualifying it with BITS_PER_LONG being 32 instead of 64. Include
<asm/bitsperlong.h> for this macro rather than <linux/types.h> as we
don't need anything else.
- Finally include <asm-generic/div64.h> last rather than first.
This has passed correctness verification with test_div64 and reduced the
module's average execution time down to 1.0668s and 0.2629s from 2.1529s
and 0.5647s respectively for an R3400 CPU @40MHz and a 5Kc CPU @160MHz.
For a reference 64-bit `do_div' code where we have the DDIVU instruction
available to do the whole calculation right away averages at 0.0660s for
the latter CPU.
Fixes: c21004cd5b ("MIPS: Rewrite <asm/div64.h> to work with gcc 4.4.0.")
Reported-by: Huacai Chen <chenhuacai@kernel.org>
Signed-off-by: Maciej W. Rozycki <macro@orcam.me.uk>
Cc: stable@vger.kernel.org # v2.6.30+
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 1690905240 upstream
There are multiple instances in the kernel where we need to include or
exclude particular instructions based on the ISA revision of the target
processor. For MIPS32 / MIPS64, the compiler exports a __mips_isa_rev
define. However, when targeting MIPS I - V, this define is absent. This
leads to each use of __mips_isa_rev having to check that it is defined
first. To simplify this, introduce the isa-rev.h header which always
exports MIPS_ISA_REV. The name is changed so as to avoid confusion with
the compiler builtin and to avoid accidentally using the builtin.
MIPS_ISA_REV is defined to the compilers builtin if provided, or 0,
which satisfies all current usages.
Suggested-by: Paul Burton <paul.burton@mips.com>
Signed-off-by: Matt Redfearn <matt.redfearn@mips.com>
Reviewed-by: Maciej W. Rozycki <macro@mips.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/18676/
Signed-off-by: James Hogan <jhogan@kernel.org>
Signed-off-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit e393fbe6fa ]
Commit 442e14a2c5 ("MIPS: Add 1074K CPU support explicitly.") split
1074K from the 74K as an unique CPU type, while it missed to add the
'CPU_1074K' in __get_cpu_type(). So let's add it back.
Fixes: 442e14a2c5 ("MIPS: Add 1074K CPU support explicitly.")
Signed-off-by: Wei Li <liwei391@huawei.com>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit bbb5946eb5 ]
Indeed according to the MIPS32 Privileged Resource Architecgture the MAAR
pair register address field either takes [12:31] bits for non-XPA systems
and [12:55] otherwise. In any case the current address mask is just
wrong for 64-bit and 32-bits XPA chips. So lets extend it to 59-bits
of physical address value. This shall cover the 64-bits architecture and
systems with XPA enabled, and won't cause any problem for non-XPA 32-bit
systems, since address values exceeding the architecture specific MAAR
mask will be just truncated with setting zeros in the unsupported upper
bits.
Co-developed-by: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru>
Signed-off-by: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru>
Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Paul Burton <paulburton@kernel.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: devicetree@vger.kernel.org
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit fe2b73dba4 upstream.
The code in decode_config4() of arch/mips/kernel/cpu-probe.c
asid_mask = MIPS_ENTRYHI_ASID;
if (config4 & MIPS_CONF4_AE)
asid_mask |= MIPS_ENTRYHI_ASIDX;
set_cpu_asid_mask(c, asid_mask);
set asid_mask to cpuinfo->asid_mask.
So in order to support variable ASID_MASK, KVM_ENTRYHI_ASID should also
be changed to cpu_asid_mask(&boot_cpu_data).
Cc: Stable <stable@vger.kernel.org> #4.9+
Reviewed-by: Aleksandar Markovic <aleksandar.qemu.devel@gmail.com>
Signed-off-by: Xing Li <lixing@loongson.cn>
[Huacai: Change current_cpu_data to boot_cpu_data for optimization]
Signed-off-by: Huacai Chen <chenhc@lemote.com>
Message-Id: <1590220602-3547-2-git-send-email-chenhc@lemote.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 12051b318b ]
The code in question is modifying a variable declared const through
pointer manipulation. Such code is explicitly undefined behavior, and
is the lone issue preventing malta_defconfig from booting when built
with Clang:
If an attempt is made to modify an object defined with a const-qualified
type through use of an lvalue with non-const-qualified type, the
behavior is undefined.
LLVM is removing such assignments. A simple fix is to not declare
variables const that you plan on modifying. Limiting the scope would be
a better method of preventing unwanted writes to such a variable.
Further, the code in question mentions "compiler bugs" without any links
to bug reports, so it is difficult to know if the issue is resolved in
GCC. The patch was authored in 2006, which would have been GCC 4.0.3 or
4.1.1. The minimal supported version of GCC in the Linux kernel is
currently 4.6.
For what its worth, there was UB before the commit in question, it just
added a barrier and got lucky IRT codegen. I don't think there's any
actual compiler bugs related, just runtime bugs due to UB.
Link: https://github.com/ClangBuiltLinux/linux/issues/610
Fixes: 966f4406d9 ("[MIPS] Work around bad code generation for <asm/io.h>.")
Reported-by: Nathan Chancellor <natechancellor@gmail.com>
Debugged-by: Nathan Chancellor <natechancellor@gmail.com>
Suggested-by: Eli Friedman <efriedma@quicinc.com>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
Tested-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Paul Burton <paul.burton@mips.com>
Cc: ralf@linux-mips.org
Cc: jhogan@kernel.org
Cc: Maciej W. Rozycki <macro@linux-mips.org>
Cc: Hassan Naveed <hnaveed@wavecomp.com>
Cc: Stephen Kitt <steve@sk2.org>
Cc: Serge Semin <fancer.lancer@gmail.com>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: linux-mips@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: clang-built-linux@googlegroups.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 682fee8028 ]
Trying to register the DSP platform device results in a null pointer
access:
[ 0.124184] CPU 0 Unable to handle kernel paging request at virtual address 00000000, epc == 804e305c, ra == 804e6f20
[ 0.135208] Oops[#1]:
[ 0.137514] CPU: 0 PID: 1 Comm: swapper Not tainted 4.14.87
...
[ 0.197117] epc : 804e305c bcm63xx_dsp_register+0x80/0xa4
[ 0.202838] ra : 804e6f20 board_register_devices+0x258/0x390
...
This happens because it tries to copy the passed platform data over the
platform_device's unpopulated platform_data.
Since this code has been broken since its submission, no driver was ever
submitted for it, and apparently nobody was using it, just remove it
instead of trying to fix it.
Fixes: e7300d04bd ("MIPS: BCM63xx: Add support for the Broadcom BCM63xx family of SOCs.")
Signed-off-by: Jonas Gorski <jonas.gorski@gmail.com>
Signed-off-by: Paul Burton <paul.burton@mips.com>
Acked-by: Florian Fainelli <f.fainelli@gmail.com>
Cc: linux-mips@linux-mips.org
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: James Hogan <jhogan@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit bbcc5672b0 upstream.
Declaring __current_thread_info as a global register variable has the
effect of preventing GCC from saving & restoring its value in cases
where the ABI would typically do so.
To quote GCC documentation:
> If the register is a call-saved register, call ABI is affected: the
> register will not be restored in function epilogue sequences after the
> variable has been assigned. Therefore, functions cannot safely return
> to callers that assume standard ABI.
When our position independent VDSO is built for the n32 or n64 ABIs all
functions it exposes should be preserving the value of $gp/$28 for their
caller, but in the presence of the __current_thread_info global register
variable GCC stops doing so & simply clobbers $gp/$28 when calculating
the address of the GOT.
In cases where the VDSO returns success this problem will typically be
masked by the caller in libc returning & restoring $gp/$28 itself, but
that is by no means guaranteed. In cases where the VDSO returns an error
libc will typically contain a fallback path which will now fail
(typically with a bad memory access) if it attempts anything which
relies upon the value of $gp/$28 - eg. accessing anything via the GOT.
One fix for this would be to move the declaration of
__current_thread_info inside the current_thread_info() function,
demoting it from global register variable to local register variable &
avoiding inadvertently creating a non-standard calling ABI for the VDSO.
Unfortunately this causes issues for clang, which doesn't support local
register variables as pointed out by commit fe92da0f35 ("MIPS: Changed
current_thread_info() to an equivalent supported by both clang and GCC")
which introduced the global register variable before we had a VDSO to
worry about.
Instead, fix this by continuing to use the global register variable for
the kernel proper but declare __current_thread_info as a simple extern
variable when building the VDSO. It should never be referenced, and will
cause a link error if it is. This resolves the calling convention issue
for the VDSO without having any impact upon the build of the kernel
itself for either clang or gcc.
Signed-off-by: Paul Burton <paulburton@kernel.org>
Fixes: ebb5e78cc6 ("MIPS: Initial implementation of a VDSO")
Reported-by: Jason A. Donenfeld <Jason@zx2c4.com>
Reviewed-by: Jason A. Donenfeld <Jason@zx2c4.com>
Tested-by: Jason A. Donenfeld <Jason@zx2c4.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Christian Brauner <christian.brauner@canonical.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: <stable@vger.kernel.org> # v4.4+
Cc: linux-mips@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 3ed6751bb8 ]
With CONFIG_MIPS_VA_BITS_48=y the build fails miserably:
CC arch/mips/kernel/asm-offsets.s
In file included from arch/mips/include/asm/pgtable.h:644,
from include/linux/mm.h:99,
from arch/mips/kernel/asm-offsets.c:15:
include/asm-generic/pgtable.h:16:2: error: #error CONFIG_PGTABLE_LEVELS is not consistent with __PAGETABLE_{P4D,PUD,PMD}_FOLDED
#error CONFIG_PGTABLE_LEVELS is not consistent with __PAGETABLE_{P4D,PUD,PMD}_FOLDED
^~~~~
include/asm-generic/pgtable.h:390:28: error: unknown type name 'p4d_t'; did you mean 'pmd_t'?
static inline int p4d_same(p4d_t p4d_a, p4d_t p4d_b)
^~~~~
pmd_t
[ ... more such errors ... ]
scripts/Makefile.build:99: recipe for target 'arch/mips/kernel/asm-offsets.s' failed
make[2]: *** [arch/mips/kernel/asm-offsets.s] Error 1
This happens because when CONFIG_MIPS_VA_BITS_48 enables 4th level of the
page tables, but neither pgtable-nop4d.h nor 5level-fixup.h are included to
cope with the 5th level.
Replace #ifdef conditions around includes of the pgtable-nop{m,u}d.h with
explicit CONFIG_PGTABLE_LEVELS and add include of 5level-fixup.h for the
case when CONFIG_PGTABLE_LEVELS==4
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Paul Burton <paulburton@kernel.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: James Hogan <jhogan@kernel.org>
Cc: linux-mips@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-mm@kvack.org
Cc: Mike Rapoport <rppt@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 1c6121c396 ]
cn58xx is compatible with cn50xx, so use the latter.
Signed-off-by: Aaro Koskinen <aaro.koskinen@iki.fi>
[paul.burton@mips.com: s/cn52xx/cn50xx/ in commit message.]
Signed-off-by: Paul Burton <paul.burton@mips.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: James Hogan <jhogan@kernel.org>
Cc: linux-mips@vger.kernel.org
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit e4f5cb1a9b ]
The vectors span more than one byte, so mark them as arrays.
Fixes the following build error when building when using GCC 8.3:
In file included from ./include/linux/string.h:19,
from ./include/linux/bitmap.h:9,
from ./include/linux/cpumask.h:12,
from ./arch/mips/include/asm/processor.h:15,
from ./arch/mips/include/asm/thread_info.h:16,
from ./include/linux/thread_info.h:38,
from ./include/asm-generic/preempt.h:5,
from ./arch/mips/include/generated/asm/preempt.h:1,
from ./include/linux/preempt.h:81,
from ./include/linux/spinlock.h:51,
from ./include/linux/mmzone.h:8,
from ./include/linux/bootmem.h:8,
from arch/mips/bcm63xx/prom.c:10:
arch/mips/bcm63xx/prom.c: In function 'prom_init':
./arch/mips/include/asm/string.h:162:11: error: '__builtin_memcpy' forming offset [2, 32] is out of the bounds [0, 1] of object 'bmips_smp_movevec' with type 'char' [-Werror=array-bounds]
__ret = __builtin_memcpy((dst), (src), __len); \
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
arch/mips/bcm63xx/prom.c:97:3: note: in expansion of macro 'memcpy'
memcpy((void *)0xa0000200, &bmips_smp_movevec, 0x20);
^~~~~~
In file included from arch/mips/bcm63xx/prom.c:14:
./arch/mips/include/asm/bmips.h:80:13: note: 'bmips_smp_movevec' declared here
extern char bmips_smp_movevec;
Fixes: 18a1eef92d ("MIPS: BMIPS: Introduce bmips.h")
Signed-off-by: Jonas Gorski <jonas.gorski@gmail.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Paul Burton <paulburton@kernel.org>
Cc: linux-mips@vger.kernel.org
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: James Hogan <jhogan@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 88356d0990 ]
Commit ac7c3e4ff4 ("compiler: enable CONFIG_OPTIMIZE_INLINING
forcibly") allows compiler to uninline functions marked as 'inline'.
In cace of cmpxchg this would cause to reference function
__cmpxchg_called_with_bad_pointer, which is a error case
for catching bugs and will not happen for correct code, if
__cmpxchg is inlined.
Signed-off-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
[paul.burton@mips.com: s/__cmpxchd/__cmpxchg in subject]
Signed-off-by: Paul Burton <paul.burton@mips.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: James Hogan <jhogan@kernel.org>
Cc: linux-mips@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 02eec6c9fc ]
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
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 47c25036b6 upstream.
Insert Branch instruction instead of NOP to make sure assembler don't
patch code in forbidden slot. In jump label function, it might
be possible to patch Control Transfer Instructions(CTIs) into
forbidden slot, which will generate Reserved Instruction exception
in MIPS release 6.
Signed-off-by: Archer Yan <ayan@wavecomp.com>
Reviewed-by: Paul Burton <paul.burton@mips.com>
[paul.burton@mips.com:
- Add MIPS prefix to subject.
- Mark for stable from v4.0, which introduced r6 support, onwards.]
Signed-off-by: Paul Burton <paul.burton@mips.com>
Cc: linux-mips@vger.kernel.org
Cc: stable@vger.kernel.org # v4.0+
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 152482580a upstream.
kvm_arch_memslots_updated() is at this point in time an x86-specific
hook for handling MMIO generation wraparound. x86 stashes 19 bits of
the memslots generation number in its MMIO sptes in order to avoid
full page fault walks for repeat faults on emulated MMIO addresses.
Because only 19 bits are used, wrapping the MMIO generation number is
possible, if unlikely. kvm_arch_memslots_updated() alerts x86 that
the generation has changed so that it can invalidate all MMIO sptes in
case the effective MMIO generation has wrapped so as to avoid using a
stale spte, e.g. a (very) old spte that was created with generation==0.
Given that the purpose of kvm_arch_memslots_updated() is to prevent
consuming stale entries, it needs to be called before the new generation
is propagated to memslots. Invalidating the MMIO sptes after updating
memslots means that there is a window where a vCPU could dereference
the new memslots generation, e.g. 0, and incorrectly reuse an old MMIO
spte that was created with (pre-wrap) generation==0.
Fixes: e59dbe09f8 ("KVM: Introduce kvm_arch_memslots_updated()")
Cc: <stable@vger.kernel.org>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 66a4059ba7 upstream.
MIPS' asm/mmzone.h includes the machine/platform mmzone.h
unconditionally, but since commit bb53fdf395 ("MIPS: c-r4k: Add
r4k_blast_scache_node for Loongson-3") is included by asm/rk4cache.h for
all r4k-style configs regardless of CONFIG_NEED_MULTIPLE_NODES.
This is problematic when CONFIG_NEED_MULTIPLE_NODES=n because both the
loongson3 & ip27 mmzone.h headers unconditionally define the NODE_DATA
preprocessor macro which is aready defined by linux/mmzone.h, resulting
in the following build error:
In file included from ./arch/mips/include/asm/mmzone.h:10,
from ./arch/mips/include/asm/r4kcache.h:23,
from arch/mips/mm/c-r4k.c:33:
./arch/mips/include/asm/mach-loongson64/mmzone.h:48: error: "NODE_DATA" redefined [-Werror]
#define NODE_DATA(n) (&__node_data[(n)]->pglist)
In file included from ./include/linux/topology.h:32,
from ./include/linux/irq.h:19,
from ./include/asm-generic/hardirq.h:13,
from ./arch/mips/include/asm/hardirq.h:16,
from ./include/linux/hardirq.h:9,
from arch/mips/mm/c-r4k.c:11:
./include/linux/mmzone.h:907: note: this is the location of the previous definition
#define NODE_DATA(nid) (&contig_page_data)
Resolve this by only including the machine mmzone.h when
CONFIG_NEED_MULTIPLE_NODES=y, which also removes the need for the empty
mach-generic version of the header which we delete.
Signed-off-by: Paul Burton <paul.burton@mips.com>
Fixes: bb53fdf395 ("MIPS: c-r4k: Add r4k_blast_scache_node for Loongson-3")
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit ff4dd232ec upstream.
ASIDs have always been stored as unsigned longs, ie. 32 bits on MIPS32
kernels. This is problematic because it is feasible for the ASID version
to overflow & wrap around to zero.
We currently attempt to handle this overflow by simply setting the ASID
version to 1, using asid_first_version(), but we make no attempt to
account for the fact that there may be mm_structs with stale ASIDs that
have versions which we now reuse due to the overflow & wrap around.
Encountering this requires that:
1) A struct mm_struct X is active on CPU A using ASID (V,n).
2) That mm is not used on CPU A for the length of time that it takes
for CPU A's asid_cache to overflow & wrap around to the same
version V that the mm had in step 1. During this time tasks using
the mm could either be sleeping or only scheduled on other CPUs.
3) Some other mm Y becomes active on CPU A and is allocated the same
ASID (V,n).
4) mm X now becomes active on CPU A again, and now incorrectly has the
same ASID as mm Y.
Where struct mm_struct ASIDs are represented above in the format
(version, EntryHi.ASID), and on a typical MIPS32 system version will be
24 bits wide & EntryHi.ASID will be 8 bits wide.
The length of time required in step 2 is highly dependent upon the CPU &
workload, but for a hypothetical 2GHz CPU running a workload which
generates a new ASID every 10000 cycles this period is around 248 days.
Due to this long period of time & the fact that tasks need to be
scheduled in just the right (or wrong, depending upon your inclination)
way, this is obviously a difficult bug to encounter but it's entirely
possible as evidenced by reports.
In order to fix this, simply extend ASIDs to 64 bits even on MIPS32
builds. This will extend the period of time required for the
hypothetical system above to encounter the problem from 28 days to
around 3 trillion years, which feels safely outside of the realms of
possibility.
The cost of this is slightly more generated code in some commonly
executed paths, but this is pretty minimal:
| Code Size Gain | Percentage
-----------------------|----------------|-------------
decstation_defconfig | +270 | +0.00%
32r2el_defconfig | +652 | +0.01%
32r6el_defconfig | +1000 | +0.01%
I have been unable to measure any change in performance of the LMbench
lat_ctx or lat_proc tests resulting from the 64b ASIDs on either
32r2el_defconfig+interAptiv or 32r6el_defconfig+I6500 systems.
Signed-off-by: Paul Burton <paul.burton@mips.com>
Suggested-by: James Hogan <jhogan@kernel.org>
References: https://lore.kernel.org/linux-mips/80B78A8B8FEE6145A87579E8435D78C30205D5F3@fzex.ruijie.com.cn/
References: https://lore.kernel.org/linux-mips/1488684260-18867-1-git-send-email-jiwei.sun@windriver.com/
Cc: Jiwei Sun <jiwei.sun@windriver.com>
Cc: Yu Huabing <yhb@ruijie.com.cn>
Cc: stable@vger.kernel.org # 2.6.12+
Cc: linux-mips@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 906d441feb ]
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
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit ea7e0480a4 upstream.
When using the legacy mmap layout, for example triggered using ulimit -s
unlimited, get_unmapped_area() fills memory from bottom to top starting
from a fairly low address near TASK_UNMAPPED_BASE.
This placement is suboptimal if the user application wishes to allocate
large amounts of heap memory using the brk syscall. With the VDSO being
located low in the user's virtual address space, the amount of space
available for access using brk is limited much more than it was prior to
the introduction of the VDSO.
For example:
# ulimit -s unlimited; cat /proc/self/maps
00400000-004ec000 r-xp 00000000 08:00 71436 /usr/bin/coreutils
004fc000-004fd000 rwxp 000ec000 08:00 71436 /usr/bin/coreutils
004fd000-0050f000 rwxp 00000000 00:00 0
00cc3000-00ce4000 rwxp 00000000 00:00 0 [heap]
2ab96000-2ab98000 r--p 00000000 00:00 0 [vvar]
2ab98000-2ab99000 r-xp 00000000 00:00 0 [vdso]
2ab99000-2ab9d000 rwxp 00000000 00:00 0
...
Resolve this by adjusting STACK_TOP to reserve space for the VDSO &
providing an address hint to get_unmapped_area() causing it to use this
space even when using the legacy mmap layout.
We reserve enough space for the VDSO, plus 1MB or 256MB for 32 bit & 64
bit systems respectively within which we randomize the VDSO base
address. Previously this randomization was taken care of by the mmap
base address randomization performed by arch_mmap_rnd(). The 1MB & 256MB
sizes are somewhat arbitrary but chosen such that we have some
randomization without taking up too much of the user's virtual address
space, which is often in short supply for 32 bit systems.
With this the VDSO is always mapped at a high address, leaving lots of
space for statically linked programs to make use of brk:
# ulimit -s unlimited; cat /proc/self/maps
00400000-004ec000 r-xp 00000000 08:00 71436 /usr/bin/coreutils
004fc000-004fd000 rwxp 000ec000 08:00 71436 /usr/bin/coreutils
004fd000-0050f000 rwxp 00000000 00:00 0
00c28000-00c49000 rwxp 00000000 00:00 0 [heap]
...
7f67c000-7f69d000 rwxp 00000000 00:00 0 [stack]
7f7fc000-7f7fd000 rwxp 00000000 00:00 0
7fcf1000-7fcf3000 r--p 00000000 00:00 0 [vvar]
7fcf3000-7fcf4000 r-xp 00000000 00:00 0 [vdso]
Signed-off-by: Paul Burton <paul.burton@mips.com>
Reported-by: Huacai Chen <chenhc@lemote.com>
Fixes: ebb5e78cc6 ("MIPS: Initial implementation of a VDSO")
Cc: Huacai Chen <chenhc@lemote.com>
Cc: linux-mips@linux-mips.org
Cc: stable@vger.kernel.org # v4.4+
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit a307188689 upstream.
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 534be1d5a2
("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 1e820da3c9 ("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.]
Signed-off-by: Huacai Chen <chenhc@lemote.com>
Signed-off-by: Paul Burton <paul.burton@mips.com>
References: 534be1d5a2 ("ARM: 6194/1: change definition of cpu_relax() for ARM11MPCore")
References: 1e820da3c9 ("MIPS: Loongson-3: Introduce CONFIG_LOONGSON3_ENHANCEMENT")
Patchwork: https://patchwork.linux-mips.org/patch/19830/
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: James Hogan <jhogan@kernel.org>
Cc: linux-mips@linux-mips.org
Cc: Fuxin Zhang <zhangfx@lemote.com>
Cc: Zhangjin Wu <wuzhangjin@gmail.com>
Cc: Huacai Chen <chenhuacai@gmail.com>
Cc: stable@vger.kernel.org # v3.15+
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit d5ea019f8a ]
This reverts commit 2a027b47db ("MIPS: BCM47XX: Enable 74K Core
ExternalSync for PCIe erratum").
Enabling ExternalSync caused a regression for BCM4718A1 (used e.g. in
Netgear E3000 and ASUS RT-N16): it simply hangs during PCIe
initialization. It's likely that BCM4717A1 is also affected.
I didn't notice that earlier as the only BCM47XX devices with PCIe I
own are:
1) BCM4706 with 2 x 14e4:4331
2) BCM4706 with 14e4:4360 and 14e4:4331
it appears that BCM4706 is unaffected.
While BCM5300X-ES300-RDS.pdf seems to document that erratum and its
workarounds (according to quotes provided by Tokunori) it seems not even
Broadcom follows them.
According to the provided info Broadcom should define CONF7_ES in their
SDK's mipsinc.h and implement workaround in the si_mips_init(). Checking
both didn't reveal such code. It *could* mean Broadcom also had some
problems with the given workaround.
Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
Signed-off-by: Paul Burton <paul.burton@mips.com>
Reported-by: Michael Marley <michael@michaelmarley.com>
Patchwork: https://patchwork.linux-mips.org/patch/20032/
URL: https://bugs.openwrt.org/index.php?do=details&task_id=1688
Cc: Tokunori Ikegami <ikegami@allied-telesis.co.jp>
Cc: Hauke Mehrtens <hauke@hauke-m.de>
Cc: Chris Packham <chris.packham@alliedtelesis.co.nz>
Cc: James Hogan <jhogan@kernel.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 2a027b47db upstream.
The erratum and workaround are described by BCM5300X-ES300-RDS.pdf as
below.
R10: PCIe Transactions Periodically Fail
Description: The BCM5300X PCIe does not maintain transaction ordering.
This may cause PCIe transaction failure.
Fix Comment: Add a dummy PCIe configuration read after a PCIe
configuration write to ensure PCIe configuration access
ordering. Set ES bit of CP0 configu7 register to enable
sync function so that the sync instruction is functional.
Resolution: hndpci.c: extpci_write_config()
hndmips.c: si_mips_init()
mipsinc.h CONF7_ES
This is fixed by the CFE MIPS bcmsi chipset driver also for BCM47XX.
Also the dummy PCIe configuration read is already implemented in the
Linux BCMA driver.
Enable ExternalSync in Config7 when CONFIG_BCMA_DRIVER_PCI_HOSTMODE=y
too so that the sync instruction is externalised.
Signed-off-by: Tokunori Ikegami <ikegami@allied-telesis.co.jp>
Reviewed-by: Paul Burton <paul.burton@mips.com>
Acked-by: Hauke Mehrtens <hauke@hauke-m.de>
Cc: Chris Packham <chris.packham@alliedtelesis.co.nz>
Cc: Rafał Miłecki <zajec5@gmail.com>
Cc: linux-mips@linux-mips.org
Cc: stable@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/19461/
Signed-off-by: James Hogan <jhogan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit a1cc7034e3 ]
While a barrier is present in the writeX() functions before the register
write, a similar barrier is missing in the readX() functions after the
register read. This could allow memory accesses following readX() to
observe stale data.
Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
Reported-by: Arnd Bergmann <arnd@arndb.de>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Paul Burton <paul.burton@mips.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/19069/
[jhogan@kernel.org: Tidy commit message]
Signed-off-by: James Hogan <jhogan@kernel.org>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit f6b7aeee8f ]
writeX() has strong ordering semantics with respect to memory updates.
In the absence of a write barrier or a compiler barrier, the compiler
can reorder register and memory update instructions. This breaks the
writeX() API.
Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Paul Burton <paul.burton@mips.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/18997/
[jhogan@kernel.org: Tidy commit message]
Signed-off-by: James Hogan <jhogan@kernel.org>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 9a9ab3078e ]
We now have a platform (Ranchu) in the "generic" platform which matches
based on the FDT compatible string using mips_machine_is_compatible(),
however that function doesn't stop at a blank struct
of_device_id::compatible as that is an array in the struct, not a
pointer to a string.
Fix the loop completion to check the first byte of the compatible array
rather than the address of the compatible array in the struct.
Fixes: eed0eabd12 ("MIPS: generic: Introduce generic DT-based board support")
Signed-off-by: James Hogan <jhogan@kernel.org>
Reviewed-by: Paul Burton <paul.burton@mips.com>
Reviewed-by: Matt Redfearn <matt.redfearn@mips.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/18580/
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 6ae1756fad upstream.
MIPS' struct compat_flock doesn't match the 32-bit struct flock, as it
has an extra short __unused before pad[4], which combined with alignment
increases the size to 40 bytes compared with struct flock's 36 bytes.
Since commit 8c6657cb50 ("Switch flock copyin/copyout primitives to
copy_{from,to}_user()"), put_compat_flock() writes the full compat_flock
struct to userland, which results in corruption of the userland word
after the struct flock when running 32-bit userlands on 64-bit kernels.
This was observed to cause a bus error exception when starting Firefox
on Debian 8 (Jessie).
Reported-by: Peter Mamonov <pmamonov@gmail.com>
Signed-off-by: James Hogan <jhogan@kernel.org>
Tested-by: Peter Mamonov <pmamonov@gmail.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-mips@linux-mips.org
Cc: <stable@vger.kernel.org> # 4.13+
Patchwork: https://patchwork.linux-mips.org/patch/18646/
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 4d2dc2cc76 upstream.
Currently, we're capping the values too low in the F_GETLK64 case. The
fields in that structure are 64-bit values, so we shouldn't need to do
any sort of fixup there.
Make sure we check that assumption at build time in the future however
by ensuring that the sizes we're copying will fit.
With this, we no longer need COMPAT_LOFF_T_MAX either, so remove it.
Fixes: 94073ad77f (fs/locks: don't mess with the address limit in compat_fcntl64)
Reported-by: Vitaly Lipatov <lav@etersoft.ru>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Reviewed-by: David Howells <dhowells@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit c8ec2041f5 upstream.
Add a custom serial.h header for MIPS, allowing platforms to override
the asm-generic version if required.
The generic platform uses this header to set BASE_BAUD to 0. The
generic platform supports multiple boards, which may have different
UART clocks. Also one of the boards supported is the Boston FPGA board,
where the UART clock depends on the loaded FPGA bitfile. As such there
is no way that the generic kernel can set a compile time default
BASE_BAUD.
Commit 31cb9a8575 ("earlycon: initialise baud field of earlycon device
structure") changed the behavior of of_setup_earlycon such that any baud
rate set in the device tree is now set in the earlycon structure. The
UART driver will then calculate a divisor based on BASE_BAUD and set it.
With MIPS generic kernels this resulted in garbage output due to the
incorrect uart clock rate being used to calculate a divisor. This
commit, combined with "serial: 8250_early: Only set divisor if valid clk
& baud" prevents the earlycon code setting a bad divisor and restores
earlycon output.
Fixes: 31cb9a8575 ("earlycon: initialise baud field of earlycon device structure")
Signed-off-by: Matt Redfearn <matt.redfearn@mips.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Huang Pei