Commit graph

8271 commits

Author SHA1 Message Date
Maciej W. Rozycki
fb0c12e677 UPSTREAM: MIPS: Fix FCSR Cause bit handling for correct SIGFPE issue
Sanitize FCSR Cause bit handling, following a trail of past attempts:

* commit 4249548454f7 ("MIPS: ptrace: Fix FP context restoration FCSR
regression"),

* commit 443c44032a ("MIPS: Always clear FCSR cause bits after
emulation"),

* commit 64bedffe49 ("MIPS: Clear [MSA]FPE CSR.Cause after
notify_die()"),

* commit b1442d39fa ("MIPS: Prevent user from setting FCSR cause
bits"),

* commit b54d2901517d ("Properly handle branch delay slots in connection
with signals.").

Specifically do not mask these bits out in ptrace(2) processing and send
a SIGFPE signal instead whenever a matching pair of an FCSR Cause and
Enable bit is seen as execution of an affected context is about to
resume.  Only then clear Cause bits, and even then do not clear any bits
that are set but masked with the respective Enable bits.  Adjust Cause
bit clearing throughout code likewise, except within the FPU emulator
proper where they are set according to IEEE 754 exceptions raised as the
operation emulated executed.  Do so so that any IEEE 754 exceptions
subject to their default handling are recorded like with operations
executed by FPU hardware.

Signed-off-by: Maciej W. Rozycki <macro@imgtec.com>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/14460/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
(cherry picked from commit 5a1aca4469fdccd5b74ba0b4e490173b2b447895)
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
2018-02-05 08:58:31 -08:00
Paul Gortmaker
1c7d67bedb UPSTREAM: MIPS: kernel: Audit and remove any unnecessary uses of module.h
Historically a lot of these existed because we did not have
a distinction between what was modular code and what was providing
support to modules via EXPORT_SYMBOL and friends.  That changed
when we forked out support for the latter into the export.h file.

This means we should be able to reduce the usage of module.h
in code that is obj-y Makefile or bool Kconfig.  The advantage
in doing so is that module.h itself sources about 15 other headers;
adding significantly to what we feed cpp, and it can obscure what
headers we are effectively using.

Since module.h was the source for init.h (for __init) and for
export.h (for EXPORT_SYMBOL) we consider each obj-y/bool instance
for the presence of either and replace as needed.

In the case of the n32/o32 files, we have to get rid of a couple
no-op MODULE_ tags to facilitate the module.h removal.  They piggy
back off the fs/ elf binary support, which is also a bool Kconfig.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/14032/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
(cherry picked from commit d9d5417755eda87db8e370e4dd2175fbd8814acc)
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
2018-02-05 08:58:31 -08:00
James Hogan
98561f4928 UPSTREAM: MIPS: c-r4k: Fix sigtramp SMP call to use kmap
Fix r4k_flush_cache_sigtramp() and local_r4k_flush_cache_sigtramp() to
flush the delay slot emulation trampoline cacheline through a kmap
rather than directly when the active_mm doesn't match that of the task
initiating the flush, a bit like local_r4k_flush_cache_page() does.

This would fix a corner case on SMP systems without hardware globalized
hit cache ops, where a migration to another CPU after the flush, where
that CPU did not have the same mm active at the time of the flush, could
result in stale icache content being executed instead of the trampoline,
e.g. from a previous delay slot emulation with a similar stack pointer.

This case was artificially triggered by replacing the icache flush with
a full indexed flush (not globalized on CM systems) and forcing the SMP
call to take place, with a test program that alternated two FPU delay
slots with a parent process repeatedly changing scheduler affinity.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/13797/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
(cherry picked from commit e523f289fe4d18d509f8827f8a293e8c5e4f51a1)
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
2018-02-05 08:58:31 -08:00
James Hogan
aff62c8fad UPSTREAM: MIPS: c-r4k: Fix protected_writeback_scache_line for EVA
The protected_writeback_scache_line() function is used by
local_r4k_flush_cache_sigtramp() to flush an FPU delay slot emulation
trampoline on the userland stack from the caches so it is visible to
subsequent instruction fetches.

Commit de8974e3f7 ("MIPS: asm: r4kcache: Add EVA cache flushing
functions") updated some protected_ cache flush functions to use EVA
CACHEE instructions via protected_cachee_op(), and commit 83fd43449b
("MIPS: r4kcache: Add EVA case for protected_writeback_dcache_line") did
the same thing for protected_writeback_dcache_line(), but
protected_writeback_scache_line() never got updated. Lets fix that now
to flush the right user address from the secondary cache rather than
some arbitrary kernel unmapped address.

This issue was spotted through code inspection, and it seems unlikely to
be possible to hit this in practice. It theoretically affect EVA kernels
on EVA capable cores with an L2 cache, where the icache fetches straight
from RAM (cpu_icache_snoops_remote_store == 0), running a hard float
userland with FPU disabled (nofpu). That both Malta and Boston platforms
override cpu_icache_snoops_remote_store to 1 suggests that all MIPS
cores fetch instructions into icache straight from L2 rather than RAM.

Fixes: de8974e3f7 ("MIPS: asm: r4kcache: Add EVA cache flushing functions")
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Leonid Yegoshin <leonid.yegoshin@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/13800/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
(cherry picked from commit 0758b116b4080d9a2a2a715bec6eee2cbd828215)
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
2018-02-05 08:58:31 -08:00
Ralf Baechle
66e81bda60 UPSTREAM: MIPS: Spelling fix lets -> let's
As noticed by Sergei in the discussion of Andrea Gelmini's patch series.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Reported-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
(cherry picked from commit 4939788eb8559754a120531c49ffa96bb30fee06)
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
2018-02-05 08:58:31 -08:00
Andrea Gelmini
d552d767e4 UPSTREAM: MIPS: R6: Fix typo
Signed-off-by: Andrea Gelmini <andrea.gelmini@gelma.net>
Cc: macro@imgtec.com
Cc: paul.burton@imgtec.com
Cc: Leonid.Yegoshin@imgtec.com
Cc: trivial@kernel.org
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/13329/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
(cherry picked from commit f5be47f5a4b74ca4bc58348a0b2a6aa4c8cba1be)
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
2018-02-05 08:58:31 -08:00
Maciej W. Rozycki
a8955d815e UPSTREAM: MIPS: traps: Correct the SIGTRAP debug ABI in do_watch' and do_trap_or_bp'
Follow our own rules set in <asm/siginfo.h> for SIGTRAP signals issued
from `do_watch' and `do_trap_or_bp' by setting the signal code to
TRAP_HWBKPT and TRAP_BRKPT respectively, for Watch exceptions and for
those Breakpoint exceptions whose originating BREAK instruction's code
does not have a special meaning.  Keep Trap exceptions unaffected as
these are not debug events.

No existing user software is expected to examine signal codes for these
signals as SI_KERNEL has been always used here.  This change makes the
MIPS port more like other Linux ports, which reduces the complexity and
provides for performance improvement in GDB.

Signed-off-by: Maciej W. Rozycki <macro@imgtec.com>
Cc: Pedro Alves <palves@redhat.com>
Cc: Luis Machado <lgustavo@codesourcery.com>
Cc: linux-mips@linux-mips.org
Cc: gdb@sourceware.org
Patchwork: https://patchwork.linux-mips.org/patch/12758/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
(cherry picked from commit 3b143cca6e1397188f507a6c727f4108861ceb8b)
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
2018-02-05 08:58:31 -08:00
Paul Burton
23080a1ef2 UPSTREAM: MIPS: inst.h: Rename cbcond{0,1}_op to pop{1,3}0_op
The opcodes currently defined in inst.h as cbcond0_op & cbcond1_op are
actually defined in the MIPS base instruction set manuals as pop10 &
pop30 respectively. Rename them as such, for consistency with the
documentation.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Acked-by: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
(cherry picked from commit 1b492600068d5fbd033196ce2bdb28735a23747e)
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
2018-02-05 08:58:31 -08:00
Paul Burton
b1529b8d20 UPSTREAM: MIPS: inst.h: Rename b{eq,ne}zcji[al]c_op to pop{6,7}6_op
The opcodes currently defined in inst.h as beqzcjic_op & bnezcjialc_op
are actually defined in the MIPS base instruction set manuals as pop66 &
pop76 respectively. Rename them as such, for consistency with the
documentation.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Acked-by: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
(cherry picked from commit 1c66b79bb3b11942a98085fd89295cf6cddae41a)
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
2018-02-05 08:58:31 -08:00
Paul Burton
f67d2acc25 UPSTREAM: MIPS: math-emu: Fix m{add,sub}.s shifts
The code in _sp_maddf (formerly ieee754sp_madd) appears to have been
copied verbatim from ieee754sp_add, and although it's adding the
unpacked "r" & "z" floats it kept using macros that operate on "x" &
"y". This led to the addition being carried out incorrectly on some
mismash of the product, accumulator & multiplicand fields. Typically
this would lead to the assertions "ze == re" & "ze <= SP_EMAX" failing
since ze & re hadn't been operated upon.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Fixes: e24c3bec3e ("MIPS: math-emu: Add support for the MIPS R6 MADDF FPU instruction")
Cc: Adam Buchbinder <adam.buchbinder@gmail.com>
Cc: Maciej W. Rozycki <macro@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/13159/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
(cherry picked from commit db57f29d50683afd75c7f8b9908af7669837c3a9)
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
2018-02-05 08:58:30 -08:00
Paul Burton
d3154ef703 UPSTREAM: MIPS: inst: Declare fsel_op for sel.fmt instruction
Declare the opcode for the MIPSr6 sel.fmt instruction, as fsel_op in
order to match other FP op names.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: Maciej W. Rozycki <macro@imgtec.com>
Cc: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/13152/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
(cherry picked from commit b6d5c4eda7a771e72b3640500e026d72c4f64419)
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
2018-02-05 08:58:30 -08:00
Paul Burton
478f521caf UPSTREAM: MIPS: math-emu: Fix code indentation
A line incrementing the re variable was indented a level too deep in
ieee754dp_mul, making the code unclear to read. Fix the indentation.
This appears to have been copied verbatim along with the rest of the
multiplication code to ieee754dp_maddf, now _dp_maddf, too so fix the
indentation there too.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/13158/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
(cherry picked from commit 5c18c936b52ae80db5737849e11f436e79b84b2d)
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
2018-02-05 08:58:30 -08:00
Paul Burton
fb2a789d16 UPSTREAM: MIPS: math-emu: Fix bit-width in ieee754dp_{mul, maddf, msubf} comments
A comment in ieee754dp_mul indicates that the code is about to perform a
32b x 32b multiplication & keep the high 32b of the result. It appears
this was copied from the single-precision multiplication code, since the
code actually goes on to perform a 64b x 64b multiplication & keep the
high 64b of the result. Fix the comment to indicate 64b.

It appears also that this comment was copied verbatim along with the
rest of the multiplication code into ieee754dp_maddf, which has since
been renamed _dp_maddf. Fix the same issue there.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/13157/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
(cherry picked from commit 95bff2410cdccfe2cf4b99f4e86165956767740e)
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
2018-02-05 08:58:30 -08:00
Paul Burton
663009749f UPSTREAM: MIPS: math-emu: Add z argument macros
Introduce macros for handling the "z" argument to maddf & msubf, making
its handling consistent with that of the "x" & "y" arguments rather than
open-coding equivalents.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: Maciej W. Rozycki <macro@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/13156/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
(cherry picked from commit e2d11e1a8398b7447d337add50521a5abc6267fd)
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
2018-02-05 08:58:30 -08:00
Paul Burton
8c50090eae UPSTREAM: MIPS: math-emu: Unify ieee754dp_m{add,sub}f
The code for emulating MIPSr6 madd.d & msub.d instructions has
previously been implemented as 2 different functions, namely
ieee754dp_maddf & ieee754dp_msubf. The difference in behaviour of these
2 instructions is merely the sign of the product, so we can easily share
the code implementing them. Do this for the double precision variant,
removing the original ieee754dp_msubf in favor of reusing the code from
ieee754dp_maddf.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/13155/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
(cherry picked from commit d728f6709bcc49c98097485e3561f1faaf52b4f3)
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
2018-02-05 08:58:30 -08:00
Paul Burton
e6ba769958 UPSTREAM: MIPS: math-emu: Unify ieee754sp_m{add,sub}f
The code for emulating MIPSr6 madd.s & msub.s instructions has
previously been implemented as 2 different functions, namely
ieee754sp_maddf & ieee754sp_msubf. The difference in behaviour of these
2 instructions is merely the sign of the product, so we can easily share
the code implementing them. Do this for the single precision variant,
removing the original ieee754sp_msubf in favor of reusing the code from
ieee754sp_maddf.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/13154/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
(cherry picked from commit 6162051e87f6ea785cb51ad99bdcf8eb0bd9cb07)
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
2018-02-05 08:58:30 -08:00
Paul Burton
476f2f0a48 UPSTREAM: MIPS: math-emu: Emulate MIPSr6 sel.fmt instruction
Add support for emulating the MIPSr6 sel.fmt instruction, which was
previously missing from the FPU emulation code. This instruction selects
its result from 2 possible source registers, based upon bit 0 of the
destination register, and is valid only for S (single) & D (double) data
types.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: Maciej W. Rozycki <macro@imgtec.com>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/13153/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
(cherry picked from commit 4b820d95dc53c15e6e727da964430a3ed60e05ef)
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
2018-02-05 08:58:30 -08:00
Paul Burton
b61e67de1a UPSTREAM: MIPS: math-emu: Fix BC1{EQ,NE}Z emulation
The conditions for branching when emulating the BC1EQZ & BC1NEZ
instructions were backwards, leading to each of those instructions being
treated as the other. Fix this by reversing the conditions, and clear up
the code a little for readability & checkpatch.

Fixes: c909ca718e ("MIPS: math-emu: Emulate missing BC1{EQ,NE}Z instructions")
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Reviewed-by: James Hogan <james.hogan@imgtec.com>
Cc: Maciej W. Rozycki <macro@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/13150/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
(cherry picked from commit 93583e178ebfdd2fadf950eef1547f305cac12ca)
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
2018-02-05 08:58:30 -08:00
Maciej W. Rozycki
9a89fca3bb UPSTREAM: MIPS: math-emu: Always propagate sNaN payload in quieting
Propagate sNaN payload in quieting in the legacy-NaN mode as well.  If
clearing the quiet bit would produce infinity, then set the next lower
trailing significand field bit, matching the SB-1 and BMIPS5000 hardware
implementations.  Some other MIPS FPU hardware implementations do
produce the default qNaN bit pattern instead.

This reverts some changes made for semantics preservation with commit
dc3ddf42 [MIPS: math-emu: Update sNaN quieting handlers], consequently
bringing back most of the semantics from before commit fdffbafb [Lots of
FPU bug fixes from Kjeld Borch Egevang.], except from the qNaN produced
in the infinity case.  Previously the default qNaN bit pattern was
produced in that case.

Signed-off-by: Maciej W. Rozycki <macro@imgtec.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Matthew Fortune <Matthew.Fortune@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/11483/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
(cherry picked from commit acd9e20cd9d0e6af5680e1870a966d8082a1130a)
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
2018-02-05 08:58:30 -08:00
Adam Buchbinder
0c23219c3a UPSTREAM: MIPS: Fix misspellings in comments.
Signed-off-by: Adam Buchbinder <adam.buchbinder@gmail.com>
Cc: linux-mips@linux-mips.org
Cc: trivial@kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/12617/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
(cherry picked from commit 92a76f6d8545efc67f03278009e9a828bdad3419)
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
2018-02-05 08:58:30 -08:00
Maciej W. Rozycki
bb61ba2136 UPSTREAM: MIPS: math-emu: Add IEEE Std 754-2008 NaN encoding emulation
Implement IEEE Std 754-2008 NaN encoding wired to the state of the
FCSR.NAN2008 bit.  Make the interpretation of the quiet bit in NaN data
as follows:

* in the legacy mode originally defined by the MIPS architecture the
  value of 1 denotes an sNaN whereas the value of 0 denotes a qNaN,

* in the 2008 mode introduced with revision 5 of the MIPS architecture
  the value of 0 denotes an sNaN whereas the value of 1 denotes a qNaN,
  following the definition of the preferred NaN encoding introduced with
  IEEE Std 754-2008.

In the 2008 mode, following the requirement of the said standard, quiet
an sNaN where needed by setting the quiet bit to 1 and leaving all the
NaN payload bits unchanged.

Update format conversion operations according to the rules set by IEEE
Std 754-2008 and the MIPS architecture.  Specifically:

* propagate NaN payload bits through conversions between floating-point
  formats such that as much information as possible is preserved and
  specifically a conversion from a narrower format to a wider format and
  then back to the original format does not change a qNaN payload in any
  way,

* conversions from a floating-point to an integer format where the
  source is a NaN, infinity or a value that would convert to an integer
  outside the range of the result format produce, under the default
  exception handling, the respective values defined by the MIPS
  architecture.

In full FPU emulation set the FIR.HAS2008 bit to 1, however do not make
any further FCSR bits writable.

Signed-off-by: Maciej W. Rozycki <macro@imgtec.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Matthew Fortune <Matthew.Fortune@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/11477/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
(cherry picked from commit 90d53a91fbd0c5a0882c29fa4279a3d2d700c76d)
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
2018-02-05 08:58:30 -08:00
Maciej W. Rozycki
71b31a91e3 UPSTREAM: MIPS: math-emu: Add IEEE Std 754-2008 ABS.fmt and NEG.fmt emulation
Implement IEEE Std 754-2008 non-arithmetic ABS.fmt and NEG.fmt emulation
wired to the state of the FCSR.ABS2008 bit.  In the non-arithmetic mode
the sign bit is altered according to the operation requested regardless
of the datum encoded in the input operand, no other bits are changed,
the resulting bit pattern is written to the output operand and no
exception is ever signalled.

Signed-off-by: Maciej W. Rozycki <macro@imgtec.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Matthew Fortune <Matthew.Fortune@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/11476/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
(cherry picked from commit 198f70589e3c0f0f50da646152443787e959228f)
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
2018-02-05 08:58:30 -08:00
Paul Burton
b38614bbdf UPSTREAM: MIPS: non-exec stack & heap when non-exec PT_GNU_STACK is present
The stack and heap have both been executable by default on MIPS until
now. This patch changes the default to be non-executable, but only for
ELF binaries with a non-executable PT_GNU_STACK header present. This
does apply to both the heap & the stack, despite the name PT_GNU_STACK,
and this matches the behaviour of other architectures like ARM & x86.

Current MIPS toolchains do not produce the PT_GNU_STACK header, which
means that we can rely upon this patch not changing the behaviour of
existing binaries. The new default will only take effect for newly
compiled binaries once toolchains are updated to support PT_GNU_STACK,
and since those binaries are newly compiled they can be compiled
expecting the change in default behaviour. Again this matches the way in
which the ARM & x86 architectures handled their implementations of
non-executable memory.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: Leonid Yegoshin <leonid.yegoshin@imgtec.com>
Cc: Maciej Rozycki <maciej.rozycki@imgtec.com>
Cc: Faraz Shahbazker <faraz.shahbazker@imgtec.com>
Cc: Raghu Gandham <raghu.gandham@imgtec.com>
Cc: Matthew Fortune <matthew.fortune@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/13765/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
(cherry picked from commit 1a770b85c1f1c1ee37afd7cef5237ffc4c970f04)
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
2018-02-05 08:58:30 -08:00
Maciej W. Rozycki
39dd84faa5 UPSTREAM: MIPS: Add IEEE Std 754 conformance mode selection
Add an `ieee754=' kernel parameter to control IEEE Std 754 conformance
mode.

Use separate flags copied from the respective CPU feature flags, and
adjusted according to the conformance mode selected, to make binaries
requesting individual NaN encoding modes accepted or rejected as needed.
Update the initial setting for FCSR and, in the full FPU emulation mode,
its read-only mask accordingly.  Accept the mode selection requested for
legacy processors as well.

As with the EF_MIPS_NAN2008 ELF file header flag adjust both ABS2008 and
NAN2008 bits at the same time, to match the choice made for hardware
currently implemented.

Signed-off-by: Maciej W. Rozycki <macro@imgtec.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Matthew Fortune <Matthew.Fortune@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/11481/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
(cherry picked from commit 503943e0e52bd3fbf014aa1d838ced37adb43121)
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
2018-02-05 08:58:30 -08:00
Maciej W. Rozycki
5dd3c3a431 UPSTREAM: MIPS: Determine the presence of IEEE Std 754-2008 features
Determine the presence of and the amount of control available over IEEE
Std 754-2008 features.

In the case of a hardware FPU being used examine the FIR register for
the presence of the HAS2008 bit and then the FCSR register for the
writability of the ABS2008 and NAN2008 bits and the hardwired state of
each of these bits if read-only.  Update the initial FCSR contents used
for threads and the FCSR writability mask accordingly.

For full FPU emulation and MIPS32 or MIPS64 processors make the FCSR
ABS2008 and NAN2008 bits writable.

Signed-off-by: Maciej W. Rozycki <macro@imgtec.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Matthew Fortune <Matthew.Fortune@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/11480/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
(cherry picked from commit 93adeaf6dadcaed943a51ad9ea2d77e24e6d70a7)
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
2018-02-05 08:58:30 -08:00
Maciej W. Rozycki
d73ca92398 UPSTREAM: MIPS: Define the legacy-NaN and 2008-NaN features
Allocate CPU option bits and define macros for the legacy-NaN and
2008-NaN IEEE Std 754 MIPS architecture features.  Unconditionally mark
the legacy-NaN feature as present across hardware and emulated
floating-point configurations.

Signed-off-by: Maciej W. Rozycki <macro@imgtec.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Matthew Fortune <Matthew.Fortune@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/11475/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
(cherry picked from commit 9519ef37a4a4e9c3c2d7d89ecbecfaf3c839208a)
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
2018-02-05 08:58:30 -08:00
Maciej W. Rozycki
43517cec9f UPSTREAM: MIPS: ELF: Interpret the NAN2008 file header flag
Handle the EF_MIPS_NAN2008 ELF file header flag and refuse execution
where there is no support in the FPU for the NaN encoding mode requested
by a binary invoked.  Ensure that the setting of the bit in the binary
matches one in any intepreter used.  Set the thread's initial FCSR
contents according to the value of the EF_MIPS_NAN2008.

Set the values of the FCSR ABS2008 and NAN2008 bits both to the same
value if possible, to take the approach taken with existing FPU hardware
into account.  As of now all implementations have both bits hardwired to
the same value, that is both are fixed at 0 or both are fixed at 1, even
though the architecture allows for implementations where the amount of
control implemented with each of these two individual bits is
independent of each other.

Signed-off-by: Maciej W. Rozycki <macro@imgtec.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Matthew Fortune <Matthew.Fortune@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/11479/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
(cherry picked from commit 2b5e869ecfcb3112f7e1267cb0328f3ff6d49b18)
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
2018-02-05 08:58:29 -08:00
Maciej W. Rozycki
380f74966e UPSTREAM: ELF: Also pass any interpreter's file header to `arch_check_elf'
Also pass any interpreter's file header to `arch_check_elf' so that any
architecture handler can have a look at it if needed.

Signed-off-by: Maciej W. Rozycki <macro@imgtec.com>
Acked-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Cc: Matthew Fortune <Matthew.Fortune@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/11478/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
(cherry picked from commit eb4bc076ff94b82fce04f6db061de597f71bd129)
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
2018-02-05 08:58:29 -08:00
Maciej W. Rozycki
18e152e051 UPSTREAM: MIPS: Use a union to access the ELF file header
Rewrite `arch_elf_pt_proc' and `arch_check_elf' using a union to access
the ELF file header.

Signed-off-by: Maciej W. Rozycki <macro@imgtec.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Matthew Fortune <Matthew.Fortune@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/11474/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
(cherry picked from commit 2ed02dd415aee71a8bf4c621a9bd65c256642b96)
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
2018-02-05 08:58:29 -08:00
Paul Burton
30bee7f938 UPSTREAM: MIPS: Fix delay slot emulation count in debugfs
Commit 432c6bacbd0c ("MIPS: Use per-mm page to execute branch delay slot
instructions") accidentally removed use of the MIPS_FPU_EMU_INC_STATS
macro from do_dsemulret, leading to the ds_emul file in debugfs always
returning zero even though we perform delay slot emulations.

Fix this by re-adding the use of the MIPS_FPU_EMU_INC_STATS macro.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Fixes: 432c6bacbd0c ("MIPS: Use per-mm page to execute branch delay slot instructions")
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/14301/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
(cherry picked from commit 116e7111c8e3cc65ceef9664741bd593483e9517)
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
2018-02-05 08:58:29 -08:00
Paul Burton
c9cd1837ca UPSTREAM: MIPS: Use per-mm page to execute branch delay slot instructions
In some cases the kernel needs to execute an instruction from the delay
slot of an emulated branch instruction. These cases include:

  - Emulated floating point branch instructions (bc1[ft]l?) for systems
    which don't include an FPU, or upon which the kernel is run with the
    "nofpu" parameter.

  - MIPSr6 systems running binaries targeting older revisions of the
    architecture, which may include branch instructions whose encodings
    are no longer valid in MIPSr6.

Executing instructions from such delay slots is done by writing the
instruction to memory followed by a trap, as part of an "emuframe", and
executing it. This avoids the requirement of an emulator for the entire
MIPS instruction set. Prior to this patch such emuframes are written to
the user stack and executed from there.

This patch moves FP branch delay emuframes off of the user stack and
into a per-mm page. Allocating a page per-mm leaves userland with access
to only what it had access to previously, and compared to other
solutions is relatively simple.

When a thread requires a delay slot emulation, it is allocated a frame.
A thread may only have one frame allocated at any one time, since it may
only ever be executing one instruction at any one time. In order to
ensure that we can free up allocated frame later, its index is recorded
in struct thread_struct. In the typical case, after executing the delay
slot instruction we'll execute a break instruction with the BRK_MEMU
code. This traps back to the kernel & leads to a call to do_dsemulret
which frees the allocated frame & moves the user PC back to the
instruction that would have executed following the emulated branch.
In some cases the delay slot instruction may be invalid, such as a
branch, or may trigger an exception. In these cases the BRK_MEMU break
instruction will not be hit. In order to ensure that frames are freed
this patch introduces dsemul_thread_cleanup() and calls it to free any
allocated frame upon thread exit. If the instruction generated an
exception & leads to a signal being delivered to the thread, or indeed
if a signal simply happens to be delivered to the thread whilst it is
executing from the struct emuframe, then we need to take care to exit
the frame appropriately. This is done by either rolling back the user PC
to the branch or advancing it to the continuation PC prior to signal
delivery, using dsemul_thread_rollback(). If this were not done then a
sigreturn would return to the struct emuframe, and if that frame had
meanwhile been used in response to an emulated branch instruction within
the signal handler then we would execute the wrong user code.

Whilst a user could theoretically place something like a compact branch
to self in a delay slot and cause their thread to become stuck in an
infinite loop with the frame never being deallocated, this would:

  - Only affect the users single process.

  - Be architecturally invalid since there would be a branch in the
    delay slot, which is forbidden.

  - Be extremely unlikely to happen by mistake, and provide a program
    with no more ability to harm the system than a simple infinite loop
    would.

If a thread requires a delay slot emulation & no frame is available to
it (ie. the process has enough other threads that all frames are
currently in use) then the thread joins a waitqueue. It will sleep until
a frame is freed by another thread in the process.

Since we now know whether a thread has an allocated frame due to our
tracking of its index, the cookie field of struct emuframe is removed as
we can be more certain whether we have a valid frame. Since a thread may
only ever have a single frame at any given time, the epc field of struct
emuframe is also removed & the PC to continue from is instead stored in
struct thread_struct. Together these changes simplify & shrink struct
emuframe somewhat, allowing twice as many frames to fit into the page
allocated for them.

The primary benefit of this patch is that we are now free to mark the
user stack non-executable where that is possible.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: Leonid Yegoshin <leonid.yegoshin@imgtec.com>
Cc: Maciej Rozycki <maciej.rozycki@imgtec.com>
Cc: Faraz Shahbazker <faraz.shahbazker@imgtec.com>
Cc: Raghu Gandham <raghu.gandham@imgtec.com>
Cc: Matthew Fortune <matthew.fortune@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/13764/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
(cherry picked from commit 432c6bacbd0c16ec210c43da411ccc3855c4c010)
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
2018-02-05 08:58:29 -08:00
Jiri Slaby
3ebefa7840 BACKPORT: exit_thread: remove empty bodies
Define HAVE_EXIT_THREAD for archs which want to do something in
exit_thread. For others, let's define exit_thread as an empty inline.

This is a cleanup before we change the prototype of exit_thread to
accept a task parameter.

[akpm@linux-foundation.org: fix mips]
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: Aurelien Jacquiot <a-jacquiot@ti.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chen Liqin <liqin.linux@gmail.com>
Cc: Chris Metcalf <cmetcalf@mellanox.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: David Howells <dhowells@redhat.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Guan Xuetao <gxt@mprc.pku.edu.cn>
Cc: Haavard Skinnemoen <hskinnemoen@gmail.com>
Cc: Hans-Christian Egtvedt <egtvedt@samfundet.no>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Jesper Nilsson <jesper.nilsson@axis.com>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Koichi Yasutake <yasutake.koichi@jp.panasonic.com>
Cc: Lennox Wu <lennox.wu@gmail.com>
Cc: Ley Foon Tan <lftan@altera.com>
Cc: Mark Salter <msalter@redhat.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Mikael Starvik <starvik@axis.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Rich Felker <dalias@libc.org>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Richard Kuo <rkuo@codeaurora.org>
Cc: Richard Weinberger <richard@nod.at>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Steven Miao <realmz6@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

(cherry picked from commit 5f56a5dfdb9bcb3bca03df59980d4d2f012cbb53)

Conflicts:
	arch/powerpc/kernel/process.c
	arch/xtensa/Kconfig
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
2018-02-05 08:58:29 -08:00
Ralf Baechle
5ea4150e17 UPSTREAM: MIPS: Make flush_thread
Avoids function calls to an empty function.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
(cherry picked from commit 04cc89d120f94131de89a6e20da27016db4782ce)
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
2018-02-05 08:58:29 -08:00
James Hogan
1e9d84070a UPSTREAM: MIPS: Properly disable FPU in start_thread()
start_thread() (called for execve(2)) clears the TIF_USEDFPU flag
without atomically disabling the FPU. With a preemptive kernel, an
unfortunately timed preemption after this could result in another
task (or KVM guest) being scheduled in with the FPU still enabled, since
lose_fpu_inatomic() only turns it off if TIF_USEDFPU is set.

Use lose_fpu(0) instead of the separate FPU / MSA management, which
should do the right thing (drop FPU properly and atomically without
saving state) and will be more future proof.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Reviewed-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/12302/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
(cherry picked from commit 76e5846d3bdf59eb1010d5607003da2dc3910bb1)
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
2018-02-05 08:58:29 -08:00
David Daney
cb7c7f371e UPSTREAM: MIPS: Select CONFIG_HANDLE_DOMAIN_IRQ and make it work.
Per the subject, always select HANDLE_DOMAIN_IRQ, and implement
set_irq_regs() so that it actually works.

Signed-off-by: David Daney <david.daney@cavium.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/12496/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
(cherry picked from commit 1d2753a66acbb101a0ec495cd13b9031ac1b171f)
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
2018-02-05 08:58:29 -08:00
Andrea Gelmini
afcd2b8978 UPSTREAM: MIPS: math-emu: Fix typo
Signed-off-by: Andrea Gelmini <andrea.gelmini@gelma.net>
Cc: macro@imgtec.com
Cc: trivial@kernel.org
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/13333/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
(cherry picked from commit e7e3346cc64fff306694bdc41908283d195339c1)
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
2018-02-05 08:58:29 -08:00
Maciej W. Rozycki
883f4325f6 UPSTREAM: MIPS: math-emu: dsemul: Remove an unused bit in ADDIUPC emulation
Avoid a reader's confusion, as the calculation is correct either way.

Signed-off-by: Maciej W. Rozycki <macro@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/12283/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
(cherry picked from commit 036aff91c30a6f15d5bf25f22827abc26b6d06c1)
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
2018-02-05 08:58:29 -08:00
Maciej W. Rozycki
c56de74165 UPSTREAM: MIPS: math-emu: dsemul: Reduce `get_isa16_mode' clutter
Signed-off-by: Maciej W. Rozycki <macro@imgtec.com>
Cc: Aurelien Jarno <aurelien@aurel32.net>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/12178/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
(cherry picked from commit 6d7b14151d7510ed434f2e587cdae9eca82fc123)
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
2018-02-05 08:58:28 -08:00
Maciej W. Rozycki
caeae55e45 UPSTREAM: MIPS: math-emu: dsemul: Correct description of the emulation frame
Remove irrelevant content from the description of the emulation frame in
`mips_dsemul', referring to bare-metal configurations.  Update the text,
reflecting the change made with commit ba3049ed40 ("MIPS: Switch FPU
emulator trap to BREAK instruction."), where we switched from using an
address error exception on an unaligned access to the use of a BREAK 514
instruction causing a breakpoint exception instead.

Signed-off-by: Maciej W. Rozycki <macro@imgtec.com>
Cc: Aurelien Jarno <aurelien@aurel32.net>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/12176/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
(cherry picked from commit 6e1715f7c34d00dc94f3cecb2526ae3ff0b0649f)
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
2018-02-05 08:58:28 -08:00
Maciej W. Rozycki
a589481cd8 UPSTREAM: MIPS: math-emu: Correct the emulation of microMIPS ADDIUPC instruction
Emulate the microMIPS ADDIUPC instruction directly in `mips_dsemul'.  If
executed in the emulation frame, this instruction produces an incorrect
result, because the value of the PC there is not the same as where the
instruction originated.

Reshape code so as to handle all microMIPS cases together.

Signed-off-by: Maciej W. Rozycki <macro@imgtec.com>
Cc: Aurelien Jarno <aurelien@aurel32.net>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/12175/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
(cherry picked from commit 69a1e6cbdf1f40d5dcae84c5a538d390b6d2c307)
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
2018-02-05 08:58:28 -08:00
Maciej W. Rozycki
e415d7547a UPSTREAM: MIPS: math-emu: Make microMIPS branch delay slot emulation work
Complement commit 102cedc32a ("MIPS: microMIPS: Floating point
support.") which introduced microMIPS FPU emulation, but did not adjust
the encoding of the BREAK instruction used to terminate the branch delay
slot emulation frame.  Consequently the execution of any such frame is
indeterminate and, depending on CPU configuration, will result in random
code execution or an offending program being terminated with SIGILL.

This is because the regular MIPS BREAK instruction is encoded with the 0
major and the 0xd minor opcode, however in the microMIPS instruction set
this major/minor opcode pair denotes an encoding reserved for the DSP
ASE.  Instead the microMIPS BREAK instruction is encoded with the 0
major and the 0x7 minor opcode.

Use the correct BREAK encoding for microMIPS FPU emulation then.

Signed-off-by: Maciej W. Rozycki <macro@imgtec.com>
Cc: Aurelien Jarno <aurelien@aurel32.net>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/12174/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
(cherry picked from commit 733b8bc183f491e8263009edf8ef184fb44a6882)
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
2018-02-05 08:58:28 -08:00
Maciej W. Rozycki
0aa09660cf UPSTREAM: MIPS: math-emu: dsemul: Fix ill formatting of microMIPS part
Correct formatting breakage introduced with commit 102cedc32a ("MIPS:
microMIPS: Floating point support."), so that further changes to this
code can be consistent.

Signed-off-by: Maciej W. Rozycki <macro@imgtec.com>
Cc: Aurelien Jarno <aurelien@aurel32.net>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/12173/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
(cherry picked from commit a87265cfedce49fa362030ae3e6ef047e08bc12c)
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
2018-02-05 08:58:28 -08:00
Maciej W. Rozycki
eeb8a2dda8 UPSTREAM: MIPS: math-emu: Correctly handle NOP emulation
Fix an issue introduced with commit 9ab4471c9f ("MIPS: math-emu:
Correct delay-slot exception propagation") where the emulation of a NOP
instruction signals the need to terminate the emulation loop.  This in
turn, if the PC has not changed from the entry to the loop, will cause
the kernel to terminate the program with SIGILL.

Consider this program:

static double div(double d)
{
	do
		d /= 2.0;
	while (d > .5);
	return d;
}

int main(int argc, char **argv)
{
	return div(argc);
}

which gets compiled to the following binary code:

00400490 <main>:
  400490:	44840000 	mtc1	a0,$f0
  400494:	3c020040 	lui	v0,0x40
  400498:	d44207f8 	ldc1	$f2,2040(v0)
  40049c:	46800021 	cvt.d.w	$f0,$f0
  4004a0:	46220002 	mul.d	$f0,$f0,$f2
  4004a4:	4620103c 	c.lt.d	$f2,$f0
  4004a8:	4501fffd 	bc1t	4004a0 <main+0x10>
  4004ac:	00000000 	nop
  4004b0:	4620000d 	trunc.w.d	$f0,$f0
  4004b4:	03e00008 	jr	ra
  4004b8:	44020000 	mfc1	v0,$f0
  4004bc:	00000000 	nop

Where the FPU emulator is used, depending on the number of command-line
arguments this code will either run to completion or terminate with
SIGILL.

If no arguments are specified, then BC1T will not be taken, NOP will not
be emulated and code will complete successfully.

If one argument is specified, then BC1T will be taken once and NOP will
be emulated.  At this point the entry PC value will be 0x400498 and the
new PC value, set by `mips_dsemul' will be 0x4004a0, the target of BC1T.
The emulation loop will terminate, but SIGILL will not be issued,
because the PC has changed.  The FPU emulator will be entered again and
on the second execution BC1T will not be taken, NOP will not be emulated
and code will complete successfully.

If two or more arguments are specified, then the first execution of BC1T
will proceed as above.  Upon reentering the FPU emulator the emulation
loop will continue to BC1T, at which point the branch will be taken and
NOP emulated again.  At this point however the entry PC value will be
0x4004a0, the same as the target of BC1T.  This will make the emulator
conclude that execution has not advanced and therefore an unsupported
FPU instruction has been encountered, and SIGILL will be sent to the
process.

Fix the problem by extending the internal API of `mips_dsemul', making
it return -1 if no delay slot emulation frame has been made, the
instruction has been handled and execution of the emulation loop needs
to continue as if nothing happened.  Remove code from `mips_dsemul' to
reproduce steps made by the emulation loop at the conclusion of each
iteration, as those will be reached normally now.  Adjust call sites
accordingly.  Document the API.

Signed-off-by: Maciej W. Rozycki <macro@imgtec.com>
Cc: Aurelien Jarno <aurelien@aurel32.net>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/12172/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
(cherry picked from commit e4553573b37c3f72533683cb5f3a1ad300b18d37)
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
2018-02-05 08:58:28 -08:00
Greg Kroah-Hartman
ef588ef53d This is the 4.4.113 stable release
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Merge 4.4.113 into android-4.4

Changes in 4.4.113
	gcov: disable for COMPILE_TEST
	x86/cpu/AMD: Make LFENCE a serializing instruction
	x86/cpu/AMD: Use LFENCE_RDTSC in preference to MFENCE_RDTSC
	x86/mm/32: Move setup_clear_cpu_cap(X86_FEATURE_PCID) earlier
	x86/asm: Use register variable to get stack pointer value
	x86/kbuild: enable modversions for symbols exported from asm
	x86/asm: Make asm/alternative.h safe from assembly
	EXPORT_SYMBOL() for asm
	kconfig.h: use __is_defined() to check if MODULE is defined
	x86/retpoline: Add initial retpoline support
	x86/spectre: Add boot time option to select Spectre v2 mitigation
	x86/retpoline/crypto: Convert crypto assembler indirect jumps
	x86/retpoline/entry: Convert entry assembler indirect jumps
	x86/retpoline/ftrace: Convert ftrace assembler indirect jumps
	x86/retpoline/hyperv: Convert assembler indirect jumps
	x86/retpoline/xen: Convert Xen hypercall indirect jumps
	x86/retpoline/checksum32: Convert assembler indirect jumps
	x86/retpoline/irq32: Convert assembler indirect jumps
	x86/retpoline: Fill return stack buffer on vmexit
	x86/retpoline: Remove compile time warning
	scsi: sg: disable SET_FORCE_LOW_DMA
	futex: Prevent overflow by strengthen input validation
	ALSA: pcm: Remove yet superfluous WARN_ON()
	ALSA: hda - Apply headphone noise quirk for another Dell XPS 13 variant
	ALSA: hda - Apply the existing quirk to iMac 14,1
	af_key: fix buffer overread in verify_address_len()
	af_key: fix buffer overread in parse_exthdrs()
	scsi: hpsa: fix volume offline state
	sched/deadline: Zero out positive runtime after throttling constrained tasks
	x86/retpoline: Add LFENCE to the retpoline/RSB filling RSB macros
	module: Add retpoline tag to VERMAGIC
	pipe: avoid round_pipe_size() nr_pages overflow on 32-bit
	x86/apic/vector: Fix off by one in error path
	Input: 88pm860x-ts - fix child-node lookup
	Input: twl6040-vibra - fix DT node memory management
	Input: twl6040-vibra - fix child-node lookup
	Input: twl4030-vibra - fix sibling-node lookup
	tracing: Fix converting enum's from the map in trace_event_eval_update()
	phy: work around 'phys' references to usb-nop-xceiv devices
	ARM: dts: kirkwood: fix pin-muxing of MPP7 on OpenBlocks A7
	can: peak: fix potential bug in packet fragmentation
	libata: apply MAX_SEC_1024 to all LITEON EP1 series devices
	dm btree: fix serious bug in btree_split_beneath()
	dm thin metadata: THIN_MAX_CONCURRENT_LOCKS should be 6
	arm64: KVM: Fix SMCCC handling of unimplemented SMC/HVC calls
	x86/cpu, x86/pti: Do not enable PTI on AMD processors
	kbuild: modversions for EXPORT_SYMBOL() for asm
	x86/mce: Make machine check speculation protected
	retpoline: Introduce start/end markers of indirect thunk
	kprobes/x86: Blacklist indirect thunk functions for kprobes
	kprobes/x86: Disable optimizing on the function jumps to indirect thunk
	x86/pti: Document fix wrong index
	x86/retpoline: Optimize inline assembler for vmexit_fill_RSB
	MIPS: AR7: ensure the port type's FCR value is used
	Linux 4.4.113

Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
2018-01-23 20:01:24 +01:00
Jonas Gorski
38bc402237 MIPS: AR7: ensure the port type's FCR value is used
commit 0a5191efe06b5103909206e4fbcff81d30283f8e upstream.

Since commit aef9a7bd9b ("serial/uart/8250: Add tunable RX interrupt
trigger I/F of FIFO buffers"), the port's default FCR value isn't used
in serial8250_do_set_termios anymore, but copied over once in
serial8250_config_port and then modified as needed.

Unfortunately, serial8250_config_port will never be called if the port
is shared between kernel and userspace, and the port's flag doesn't have
UPF_BOOT_AUTOCONF, which would trigger a serial8250_config_port as well.

This causes garbled output from userspace:

[    5.220000] random: procd urandom read with 49 bits of entropy available
ers
   [kee

Fix this by forcing it to be configured on boot, resulting in the
expected output:

[    5.250000] random: procd urandom read with 50 bits of entropy available
Press the [f] key and hit [enter] to enter failsafe mode
Press the [1], [2], [3] or [4] key and hit [enter] to select the debug level

Fixes: aef9a7bd9b ("serial/uart/8250: Add tunable RX interrupt trigger I/F of FIFO buffers")
Signed-off-by: Jonas Gorski <jonas.gorski@gmail.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Yoshihiro YUNOMAE <yoshihiro.yunomae.ez@hitachi.com>
Cc: Florian Fainelli <f.fainelli@gmail.com>
Cc: Nicolas Schichan <nschichan@freebox.fr>
Cc: linux-mips@linux-mips.org
Cc: linux-serial@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/17544/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Cc: James Hogan <jhogan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-01-23 19:50:18 +01:00
Greg Kroah-Hartman
5f6325b148 This is the 4.4.112 stable release
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Merge 4.4.112 into android-4.4

Changes in 4.4.112
	dm bufio: fix shrinker scans when (nr_to_scan < retain_target)
	KVM: Fix stack-out-of-bounds read in write_mmio
	can: gs_usb: fix return value of the "set_bittiming" callback
	IB/srpt: Disable RDMA access by the initiator
	MIPS: Validate PR_SET_FP_MODE prctl(2) requests against the ABI of the task
	MIPS: Factor out NT_PRFPREG regset access helpers
	MIPS: Guard against any partial write attempt with PTRACE_SETREGSET
	MIPS: Consistently handle buffer counter with PTRACE_SETREGSET
	MIPS: Fix an FCSR access API regression with NT_PRFPREG and MSA
	MIPS: Also verify sizeof `elf_fpreg_t' with PTRACE_SETREGSET
	MIPS: Disallow outsized PTRACE_SETREGSET NT_PRFPREG regset accesses
	net/mac80211/debugfs.c: prevent build failure with CONFIG_UBSAN=y
	kvm: vmx: Scrub hardware GPRs at VM-exit
	x86/vsdo: Fix build on PARAVIRT_CLOCK=y, KVM_GUEST=n
	x86/acpi: Handle SCI interrupts above legacy space gracefully
	iommu/arm-smmu-v3: Don't free page table ops twice
	ALSA: pcm: Remove incorrect snd_BUG_ON() usages
	ALSA: pcm: Add missing error checks in OSS emulation plugin builder
	ALSA: pcm: Abort properly at pending signal in OSS read/write loops
	ALSA: pcm: Allow aborting mutex lock at OSS read/write loops
	ALSA: aloop: Release cable upon open error path
	ALSA: aloop: Fix inconsistent format due to incomplete rule
	ALSA: aloop: Fix racy hw constraints adjustment
	x86/acpi: Reduce code duplication in mp_override_legacy_irq()
	mm/compaction: fix invalid free_pfn and compact_cached_free_pfn
	mm/compaction: pass only pageblock aligned range to pageblock_pfn_to_page
	mm/page-writeback: fix dirty_ratelimit calculation
	mm/zswap: use workqueue to destroy pool
	zswap: don't param_set_charp while holding spinlock
	locks: don't check for race with close when setting OFD lock
	futex: Replace barrier() in unqueue_me() with READ_ONCE()
	locking/mutex: Allow next waiter lockless wakeup
	usbvision fix overflow of interfaces array
	usb: musb: ux500: Fix NULL pointer dereference at system PM
	r8152: fix the wake event
	r8152: use test_and_clear_bit
	r8152: adjust ALDPS function
	lan78xx: use skb_cow_head() to deal with cloned skbs
	sr9700: use skb_cow_head() to deal with cloned skbs
	smsc75xx: use skb_cow_head() to deal with cloned skbs
	cx82310_eth: use skb_cow_head() to deal with cloned skbs
	x86/mm/pat, /dev/mem: Remove superfluous error message
	hwrng: core - sleep interruptible in read
	sysrq: Fix warning in sysrq generated crash.
	xhci: Fix ring leak in failure path of xhci_alloc_virt_device()
	Revert "userfaultfd: selftest: vm: allow to build in vm/ directory"
	x86/pti/efi: broken conversion from efi to kernel page table
	8021q: fix a memory leak for VLAN 0 device
	ip6_tunnel: disable dst caching if tunnel is dual-stack
	net: core: fix module type in sock_diag_bind
	RDS: Heap OOB write in rds_message_alloc_sgs()
	RDS: null pointer dereference in rds_atomic_free_op
	sh_eth: fix TSU resource handling
	sh_eth: fix SH7757 GEther initialization
	net: stmmac: enable EEE in MII, GMII or RGMII only
	ipv6: fix possible mem leaks in ipv6_make_skb()
	crypto: algapi - fix NULL dereference in crypto_remove_spawns()
	rbd: set max_segments to USHRT_MAX
	x86/microcode/intel: Extend BDW late-loading with a revision check
	KVM: x86: Add memory barrier on vmcs field lookup
	drm/vmwgfx: Potential off by one in vmw_view_add()
	kaiser: Set _PAGE_NX only if supported
	bpf: add bpf_patch_insn_single helper
	bpf: don't (ab)use instructions to store state
	bpf: move fixup_bpf_calls() function
	bpf: refactor fixup_bpf_calls()
	bpf: adjust insn_aux_data when patching insns
	bpf: prevent out-of-bounds speculation
	bpf, array: fix overflow in max_entries and undefined behavior in index_mask
	iscsi-target: Make TASK_REASSIGN use proper se_cmd->cmd_kref
	target: Avoid early CMD_T_PRE_EXECUTE failures during ABORT_TASK
	USB: serial: cp210x: add IDs for LifeScan OneTouch Verio IQ
	USB: serial: cp210x: add new device ID ELV ALC 8xxx
	usb: misc: usb3503: make sure reset is low for at least 100us
	USB: fix usbmon BUG trigger
	usbip: remove kernel addresses from usb device and urb debug msgs
	staging: android: ashmem: fix a race condition in ASHMEM_SET_SIZE ioctl
	Bluetooth: Prevent stack info leak from the EFS element.
	uas: ignore UAS for Norelsys NS1068(X) chips
	e1000e: Fix e1000_check_for_copper_link_ich8lan return value.
	x86/Documentation: Add PTI description
	x86/cpu: Factor out application of forced CPU caps
	x86/cpufeatures: Make CPU bugs sticky
	x86/cpufeatures: Add X86_BUG_CPU_INSECURE
	x86/pti: Rename BUG_CPU_INSECURE to BUG_CPU_MELTDOWN
	x86/cpufeatures: Add X86_BUG_SPECTRE_V[12]
	x86/cpu: Merge bugs.c and bugs_64.c
	sysfs/cpu: Add vulnerability folder
	x86/cpu: Implement CPU vulnerabilites sysfs functions
	sysfs/cpu: Fix typos in vulnerability documentation
	x86/alternatives: Fix optimize_nops() checking
	x86/alternatives: Add missing '\n' at end of ALTERNATIVE inline asm
	selftests/x86: Add test_vsyscall
	Linux 4.4.112

Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
2018-01-17 10:14:26 +01:00
Maciej W. Rozycki
f2c131d05d MIPS: Disallow outsized PTRACE_SETREGSET NT_PRFPREG regset accesses
commit c8c5a3a24d395b14447a9a89d61586a913840a3b upstream.

Complement commit c23b3d1a53 ("MIPS: ptrace: Change GP regset to use
correct core dump register layout") and also reject outsized
PTRACE_SETREGSET requests to the NT_PRFPREG regset, like with the
NT_PRSTATUS regset.

Signed-off-by: Maciej W. Rozycki <macro@mips.com>
Fixes: c23b3d1a53 ("MIPS: ptrace: Change GP regset to use correct core dump register layout")
Cc: James Hogan <james.hogan@mips.com>
Cc: Paul Burton <Paul.Burton@mips.com>
Cc: Alex Smith <alex@alex-smith.me.uk>
Cc: Dave Martin <Dave.Martin@arm.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/17930/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-01-17 09:35:25 +01:00
Maciej W. Rozycki
725679dc78 MIPS: Also verify sizeof `elf_fpreg_t' with PTRACE_SETREGSET
commit 006501e039eec411842bb3150c41358867d320c2 upstream.

Complement commit d614fd58a283 ("mips/ptrace: Preserve previous
registers for short regset write") and like with the PTRACE_GETREGSET
ptrace(2) request also apply a BUILD_BUG_ON check for the size of the
`elf_fpreg_t' type in the PTRACE_SETREGSET request handler.

Signed-off-by: Maciej W. Rozycki <macro@mips.com>
Fixes: d614fd58a283 ("mips/ptrace: Preserve previous registers for short regset write")
Cc: James Hogan <james.hogan@mips.com>
Cc: Paul Burton <Paul.Burton@mips.com>
Cc: Alex Smith <alex@alex-smith.me.uk>
Cc: Dave Martin <Dave.Martin@arm.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/17929/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-01-17 09:35:25 +01:00
Maciej W. Rozycki
9584ae52bd MIPS: Fix an FCSR access API regression with NT_PRFPREG and MSA
commit be07a6a1188372b6d19a3307ec33211fc9c9439d upstream.

Fix a commit 72b22bbad1 ("MIPS: Don't assume 64-bit FP registers for
FP regset") public API regression, then activated by commit 1db1af84d6
("MIPS: Basic MSA context switching support"), that caused the FCSR
register not to be read or written for CONFIG_CPU_HAS_MSA kernel
configurations (regardless of actual presence or absence of the MSA
feature in a given processor) with ptrace(2) PTRACE_GETREGSET and
PTRACE_SETREGSET requests nor recorded in core dumps.

This is because with !CONFIG_CPU_HAS_MSA configurations the whole of
`elf_fpregset_t' array is bulk-copied as it is, which includes the FCSR
in one half of the last, 33rd slot, whereas with CONFIG_CPU_HAS_MSA
configurations array elements are copied individually, and then only the
leading 32 FGR slots while the remaining slot is ignored.

Correct the code then such that only FGR slots are copied in the
respective !MSA and MSA helpers an then the FCSR slot is handled
separately in common code.  Use `ptrace_setfcr31' to update the FCSR
too, so that the read-only mask is respected.

Retrieving a correct value of FCSR is important in debugging not only
for the human to be able to get the right interpretation of the
situation, but for correct operation of GDB as well.  This is because
the condition code bits in FSCR are used by GDB to determine the
location to place a breakpoint at when single-stepping through an FPU
branch instruction.  If such a breakpoint is placed incorrectly (i.e.
with the condition reversed), then it will be missed, likely causing the
debuggee to run away from the control of GDB and consequently breaking
the process of investigation.

Fortunately GDB continues using the older PTRACE_GETFPREGS ptrace(2)
request which is unaffected, so the regression only really hits with
post-mortem debug sessions using a core dump file, in which case
execution, and consequently single-stepping through branches is not
possible.  Of course core files created by buggy kernels out there will
have the value of FCSR recorded clobbered, but such core files cannot be
corrected and the person using them simply will have to be aware that
the value of FCSR retrieved is not reliable.

Which also means we can likely get away without defining a replacement
API which would ensure a correct value of FSCR to be retrieved, or none
at all.

This is based on previous work by Alex Smith, extensively rewritten.

Signed-off-by: Alex Smith <alex@alex-smith.me.uk>
Signed-off-by: James Hogan <james.hogan@mips.com>
Signed-off-by: Maciej W. Rozycki <macro@mips.com>
Fixes: 72b22bbad1 ("MIPS: Don't assume 64-bit FP registers for FP regset")
Cc: Paul Burton <Paul.Burton@mips.com>
Cc: Dave Martin <Dave.Martin@arm.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/17928/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-01-17 09:35:25 +01:00
Maciej W. Rozycki
a6972f8bd2 MIPS: Consistently handle buffer counter with PTRACE_SETREGSET
commit 80b3ffce0196ea50068885d085ff981e4b8396f4 upstream.

Update commit d614fd58a283 ("mips/ptrace: Preserve previous registers
for short regset write") bug and consistently consume all data supplied
to `fpr_set_msa' with the ptrace(2) PTRACE_SETREGSET request, such that
a zero data buffer counter is returned where insufficient data has been
given to fill a whole number of FP general registers.

In reality this is not going to happen, as the caller is supposed to
only supply data covering a whole number of registers and it is verified
in `ptrace_regset' and again asserted in `fpr_set', however structuring
code such that the presence of trailing partial FP general register data
causes `fpr_set_msa' to return with a non-zero data buffer counter makes
it appear that this trailing data will be used if there are subsequent
writes made to FP registers, which is going to be the case with the FCSR
once the missing write to that register has been fixed.

Fixes: d614fd58a283 ("mips/ptrace: Preserve previous registers for short regset write")
Signed-off-by: Maciej W. Rozycki <macro@mips.com>
Cc: James Hogan <james.hogan@mips.com>
Cc: Paul Burton <Paul.Burton@mips.com>
Cc: Alex Smith <alex@alex-smith.me.uk>
Cc: Dave Martin <Dave.Martin@arm.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/17927/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-01-17 09:35:25 +01:00