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  1. 28 3月, 2015 11 次提交
    • J
      MIPS: MSA: Fix big-endian FPR_IDX implementation · 1f3a2c6e
      由 James Hogan 提交于 
      The maximum word size is 64-bits since MSA state is saved using st.d
which stores two 64-bit words, therefore reimplement FPR_IDX using xor,
and only within each 64-bit word.
Signed-off-by: NJames Hogan <james.hogan@imgtec.com>
Signed-off-by: NPaul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/9169/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>
      1f3a2c6e
    • J
      Revert "MIPS: Don't assume 64-bit FP registers for context switch" · 466aec5f
      由 James Hogan 提交于 
      This reverts commit 02987633.

The basic premise of the patch was incorrect since MSA context
(including FP state) is saved using st.d which stores two consecutive
64-bit words in memory rather than a single 128-bit word. This means
that even with big endian MSA, the FP state is still in the first 64-bit
word.
Signed-off-by: NJames Hogan <james.hogan@imgtec.com>
Signed-off-by: NPaul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/9168/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>
      466aec5f
    • P
      MIPS: disable FPU if the mode is unsupported · 84ab45b3
      由 Paul Burton 提交于 
      The expected semantics of __enable_fpu are for the FPU to be enabled
in the given mode if possible, otherwise for the FPU to be left
disabled and SIGFPE returned. The FPU was incorrectly being left
enabled in cases where the desired value for FR was unavailable.
Without ensuring the FPU is disabled in this case, it would be
possible for userland to go on to execute further FP instructions
natively in the incorrect mode, rather than those instructions being
trapped & emulated as they need to be.
Signed-off-by: NPaul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/9167/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>
      84ab45b3
    • P
      MIPS: prevent FP context set via ptrace being discarded · ac9ad83b
      由 Paul Burton 提交于 
      If a ptracee has not used the FPU and the ptracer sets its FP context
using PTRACE_POKEUSR, PTRACE_SETFPREGS or PTRACE_SETREGSET then that
context will be discarded upon either the ptracee using the FPU or a
further write to the context via ptrace. Prevent this loss by recording
that the task has "used" math once its FP context has been written to.
The context initialisation code that was present for the PTRACE_POKEUSR
case is reused for the other 2 cases to provide consistent behaviour
for the different ptrace requests.
Signed-off-by: NPaul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/9166/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>
      ac9ad83b
    • P
      MIPS: Ensure FCSR cause bits are clear after invoking FPU emulator · ad70c13a
      由 Paul Burton 提交于 
      When running the emulator to handle an instruction that raised an FP
unimplemented operation exception, the FCSR cause bits were being
cleared. This is done to ensure that the kernel does not take an FP
exception when later restoring FP context to registers. However, this
was not being done when the emulator is invoked in response to a
coprocessor unusable exception. This happens in 2 cases:

  - There is no FPU present in the system. In this case things were
    OK, since the FP context is never restored to hardware registers
    and thus no FP exception may be raised when restoring FCSR.

  - The FPU could not be configured to the mode required by the task.
    In this case it would be possible for the emulator to set cause
    bits which are later restored to hardware if the task migrates
    to a CPU whose associated FPU does support its mode requirements,
    or if the tasks FP mode requirements change.

Consistently clear the cause bits after invoking the emulator, by moving
the clearing to process_fpemu_return and ensuring this is always called
before the tasks FP context is restored. This will make it easier to
catch further paths invoking the emulator in future, as will be
introduced in further patches.
Signed-off-by: NPaul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/9165/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>
      ad70c13a
    • P
      MIPS: clear MSACSR cause bits when handling MSA FP exception · 091be550
      由 Paul Burton 提交于 
      Much like for traditional scalar FP exceptions, the cause bits in the
MSACSR register need to be cleared following an MSA FP exception.
Without doing so the exception will simply be raised again whenever
the kernel restores MSACSR from a tasks saved context, leading to
undesirable spurious exceptions. Clear the cause bits from the
handle_msa_fpe function, mirroring the way handle_fpe clears the
cause bits in FCSR.
Signed-off-by: NPaul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/9164/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>
      091be550
    • P
      MIPS: wrap cfcmsa & ctcmsa accesses for toolchains with MSA support · e1bebbab
      由 Paul Burton 提交于 
      Uses of the cfcmsa & ctcmsa instructions were not being wrapped by a
macro in the case where the toolchain supports MSA, since the arguments
exactly match a typical use of the instructions. However using current
toolchains this leads to errors such as:

  arch/mips/kernel/genex.S:437: Error: opcode not supported on this processor: mips32r2 (mips32r2) `cfcmsa $5,1'

Thus uses of the instructions must be in the context of a ".set msa"
directive, however doing that from the users of the instructions would
be messy due to the possibility that the toolchain does not support
MSA. Fix this by renaming the macros (prepending an underscore) in order
to avoid recursion when attempting to emit the instructions, and provide
implementations for the TOOLCHAIN_SUPPORTS_MSA case which ".set msa" as
appropriate.
Signed-off-by: NPaul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/9163/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>
      e1bebbab
    • P
      MIPS: remove MSA macro recursion · a3a49810
      由 Paul Burton 提交于 
      Recursive macros made the code more concise & worked great for the
case where the toolchain doesn't support MSA. However, with toolchains
which do support MSA they lead to build failures such as:

  arch/mips/kernel/r4k_switch.S: Assembler messages:
  arch/mips/kernel/r4k_switch.S:148: Error: invalid operands `insert.w $w(0+1)[2],$1'
  arch/mips/kernel/r4k_switch.S:148: Error: invalid operands `insert.w $w(0+1)[3],$1'
  arch/mips/kernel/r4k_switch.S:148: Error: invalid operands `insert.w $w((0+1)+1)[2],$1'
  arch/mips/kernel/r4k_switch.S:148: Error: invalid operands `insert.w $w((0+1)+1)[3],$1'
  ...

Drop the recursion from msa_init_all_upper invoking the msa_init_upper
macro explicitly for each vector register.
Signed-off-by: NPaul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/9162/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>
      a3a49810
    • P
      MIPS: assume at as source/dest of MSA copy/insert instructions · f23ce388
      由 Paul Burton 提交于 
      Assuming at ($1) as the source or destination register of copy or
insert instructions:

  - Simplifies the macros providing those instructions for toolchains
    without MSA support.

  - Avoids an unnecessary move instruction when at is used as the source
    or destination register anyway.

  - Is sufficient for the uses to be introduced in the kernel by a
    subsequent patch.

Note that due to a patch ordering snafu on my part this also fixes the
currently broken build with MSA support enabled. The build has been
broken since commit c9017757 "MIPS: init upper 64b of vector
registers when MSA is first used", which this patch should have
preceeded.
Signed-off-by: NPaul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/9161/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>
      f23ce388
    • P
      MIPS: Push .set mips64r* into the functions needing it · 631afc65
      由 Paul Burton 提交于 
      The {save,restore}_fp_context{,32} functions require that the assembler
allows the use of sdc instructions on any FP register, and this is
acomplished by setting the arch to mips64r2 or mips64r6
(using MIPS_ISA_ARCH_LEVEL_RAW).

However this has the effect of enabling the assembler to use mips64
instructions in the expansion of pseudo-instructions. This was done in
the (now-reverted) commit eec43a22 "MIPS: Save/restore MSA context
around signals" which led to my mistakenly believing that there was an
assembler bug, when in reality the assembler was just emitting mips64
instructions. Avoid the issue for future commits which will add code to
r4k_fpu.S by pushing the .set MIPS_ISA_ARCH_LEVEL_RAW directives into
the functions that require it, and remove the spurious assertion
declaring the assembler bug.
Signed-off-by: NPaul Burton <paul.burton@imgtec.com>
[james.hogan@imgtec.com: Rebase on v4.0-rc1 and reword commit message to
 reflect use of MIPS_ISA_ARCH_LEVEL_RAW]
Signed-off-by: NJames Hogan <james.hogan@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/9612/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>
      631afc65
    • J
      MIPS: lose_fpu(): Disable FPU when MSA enabled · acaf6a97
      由 James Hogan 提交于 
      The lose_fpu() function only disables the FPU in CP0_Status.CU1 if the
FPU is in use and MSA isn't enabled.

This isn't necessarily a problem because KSTK_STATUS(current), the
version of CP0_Status stored on the kernel stack on entry from user
mode, does always get updated and gets restored when returning to user
mode, but I don't think it was intended, and it is inconsistent with the
case of only the FPU being in use. Sometimes leaving the FPU enabled may
also mask kernel bugs where FPU operations are executed when the FPU
might not be enabled.

So lets disable the FPU in the MSA case too.

Fixes: 33c771ba ("MIPS: save/disable MSA in lose_fpu")
Signed-off-by: NJames Hogan <james.hogan@imgtec.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/9323/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>
      acaf6a97
  3. 03 3月, 2015 2 次提交
  5. 21 2月, 2015 2 次提交
  7. 20 2月, 2015 24 次提交
  9. 19 2月, 2015 1 次提交