In microMIPS kernels, handle_signal() sets the isa16 mode bit in the
vdso address so that the sigreturn trampolines (which are offset from
the VDSO) get executed as microMIPS.
However commit ebb5e78cc6 ("MIPS: Initial implementation of a VDSO")
changed the offsets to come from the VDSO image, which already have the
isa16 mode bit set correctly since they're extracted from the VDSO
shared library symbol table.
Drop the isa16 mode bit handling from handle_signal() to fix sigreturn
for cores which support both microMIPS and normal MIPS. This doesn't fix
microMIPS only cores, since the VDSO is still built for normal MIPS, but
thats a separate problem.
Fixes: ebb5e78cc6 ("MIPS: Initial implementation of a VDSO")
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: <stable@vger.kernel.org> # 4.4.x-
Patchwork: https://patchwork.linux-mips.org/patch/13348/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Avoid an aliasing issue causing a build error in VDSO:
In file included from include/linux/srcu.h:34:0,
from include/linux/notifier.h:15,
from ./arch/mips/include/asm/uprobes.h:9,
from include/linux/uprobes.h:61,
from include/linux/mm_types.h:13,
from ./arch/mips/include/asm/vdso.h:14,
from arch/mips/vdso/vdso.h:27,
from arch/mips/vdso/gettimeofday.c:11:
include/linux/workqueue.h: In function 'work_static':
include/linux/workqueue.h:186:2: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing]
return *work_data_bits(work) & WORK_STRUCT_STATIC;
^
cc1: all warnings being treated as errors
make[2]: *** [arch/mips/vdso/gettimeofday.o] Error 1
with a CONFIG_DEBUG_OBJECTS_WORK configuration and GCC 5.2.0. Include
`-fno-strict-aliasing' along with compiler options used, as required for
kernel code, fixing a problem present since the introduction of VDSO
with commit ebb5e78cc6 ("MIPS: Initial implementation of a VDSO").
Thanks to Tejun for diagnosing this properly!
Signed-off-by: Maciej W. Rozycki <macro@imgtec.com>
Reviewed-by: James Hogan <james.hogan@imgtec.com>
Fixes: ebb5e78cc6 ("MIPS: Initial implementation of a VDSO")
Cc: Tejun Heo <tj@kernel.org>
Cc: linux-mips@linux-mips.org
Cc: stable@vger.kernel.org # v4.3+
Patchwork: https://patchwork.linux-mips.org/patch/13357/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
The Hardware page Table Walker (HTW) is being misconfigured on 64-bit
kernels. The PWSize.PS (pointer size) bit determines whether pointers
within directories are loaded as 32-bit or 64-bit addresses, but was
never being set to 1 for 64-bit kernels where the unsigned long in pgd_t
is 64-bits wide.
This actually reduces rather than improves performance when the HTW is
enabled on P6600 since the HTW is initiated lots, but walks are all
aborted due I think to bad intermediate pointers.
Since we were already taking the width of the PTEs into account by
setting PWSize.PTEW, which is the left shift applied to the page table
index *in addition to* the native pointer size, we also need to reduce
PTEW by 1 when PS=1. This is done by calculating PTEW based on the
relative size of pte_t compared to pgd_t.
Finally in order for the HTW to be used when PS=1, the appropriate
XK/XS/XU bits corresponding to the different 64-bit segments need to be
set in PWCtl. We enable only XU for now to enable walking for XUSeg.
Supporting walking for XKSeg would be a bit more involved so is left for
a future patch. It would either require the use of a per-CPU top level
base directory if supported by the HTW (a bit like pgd_current but with
a second entry pointing at swapper_pg_dir), or the HTW would prepend bit
63 of the address to the global directory index which doesn't really
match how we split user and kernel page directories.
Fixes: cab25bc753 ("MIPS: Extend hardware table walking support to MIPS64")
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/13364/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Simplify the DSP instruction wrapper macros which use explicit encodings
for microMIPS and normal MIPS by using the new encoding macros and
removing duplication.
To me this makes it easier to read since it is much shorter, but it also
ensures .insn is used, preventing objdump disassembling the microMIPS
code as normal MIPS.
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/13314/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Hardcoded MIPS instruction encodings are provided for tlbinvf, mfhc0 &
mthc0 instructions, but microMIPS encodings are missing. I doubt any
microMIPS cores exist at present which support these instructions, but
the microMIPS encodings exist, and microMIPS cores may support them in
the future. Add the missing microMIPS encodings using the new macros.
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/13313/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
When the toolchain doesn't support MSA we encode MSA instructions
explicitly in assembly. Unfortunately we use .word for both MIPS and
microMIPS encodings which is wrong, since 32-bit microMIPS instructions
are made up from a pair of halfwords.
- The most significant halfword always comes first, so for little endian
builds the halves will be emitted in the wrong order.
- 32-bit alignment isn't guaranteed, so the assembler may insert a
16-bit nop instruction to pad the instruction stream to a 32-bit
boundary.
Use the new instruction encoding macros to encode microMIPS MSA
instructions correctly.
Fixes: d96cc3d1ec ("MIPS: Add microMIPS MSA support.")
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paul Burton <Paul.Burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/13312/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Toolchains may be used which support microMIPS but not VZ instructions
(i.e. binutis 2.22 & 2.23), so extend the explicitly encoded versions of
the guest COP0 register & guest TLB access macros to support microMIPS
encodings too, using the new macros.
This prevents non-microMIPS instructions being executed in microMIPS
mode during CPU probe on cores supporting VZ (e.g. M5150), which cause
reserved instruction exceptions early during boot.
Fixes: bad50d7925 ("MIPS: Fix VZ probe gas errors with binutils <2.24")
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/13311/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
To allow simplification of macros which use inline assembly to
explicitly encode instructions, add a few simple abstractions to
mipsregs.h which expand to specific microMIPS or normal MIPS encodings
depending on what type of kernel is being built:
_ASM_INSN_IF_MIPS(_enc) : Emit a 32bit MIPS instruction if microMIPS is
not enabled.
_ASM_INSN32_IF_MM(_enc) : Emit a 32bit microMIPS instruction if enabled.
_ASM_INSN16_IF_MM(_enc) : Emit a 16bit microMIPS instruction if enabled.
The macros can be used one after another since the MIPS / microMIPS
macros are mutually exclusive, for example:
__asm__ __volatile__(
".set push\n\t"
".set noat\n\t"
"# mfgc0 $1, $%1, %2\n\t"
_ASM_INSN_IF_MIPS(0x40610000 | %1 << 11 | %2)
_ASM_INSN32_IF_MM(0x002004fc | %1 << 16 | %2 << 11)
"move %0, $1\n\t"
".set pop"
: "=r" (__res)
: "i" (source), "i" (sel));
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/13310/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Linus Torvalds
Anna-Maria Gleixner
James Hogan
Antony Pavlov
Maciej W. Rozycki
Matt Redfearn
Harvey Hunt
Ralf Baechle
Andrea Gelmini