Commit Graph

32 Commits

Author SHA1 Message Date
Paul Burton 9ec55930e0
MIPS: Stub asm/fpu.h functions
Provide stub versions of functions in asm/fpu.h when
CONFIG_MIPS_FP_SUPPORT=n. Two approaches are taken to the functions
provided:

  - Functions which can safely be called when FP is not enabled provide
    stubs which return an error where appropriate or are simple no-ops.

  - Functions which should only ever be called in cases where
    cpu_has_fpu is true or the FPU was successfully enabled are declared
    extern & annotated with __compiletime_error() to detect cases in
    which they are called incorrectly.

Signed-off-by: Paul Burton <paul.burton@mips.com>
Patchwork: https://patchwork.linux-mips.org/patch/21006/
Cc: linux-mips@linux-mips.org
2018-11-09 10:23:15 -08:00
Paul Burton 7d3713a4aa
MIPS: Drop forward declarations of sigcontext in asm/fpu.h
asm/fpu.h contains forward declarations of struct sigcontext & struct
sigcontext32 which appear to have been unused since commit 137f6f3e28
("MIPS: Cleanup signal code initialization"). Remove the dead code.

Signed-off-by: Paul Burton <paul.burton@mips.com>
Patchwork: https://patchwork.linux-mips.org/patch/21015/
Cc: linux-mips@linux-mips.org
2018-11-09 10:23:14 -08:00
Paul Burton cc97ab235f
MIPS: Simplify FP context initialization
MIPS has up until now had 3 different ways for a task's floating point
context to be initialized:

  - If the task's first use of FP involves it gaining ownership of an
    FPU then _init_fpu() is used to initialize the FPU's registers such
    that they all contain ~0, and the FPU registers will be stored to
    struct thread_info later (eg. when context switching).

  - If the task first uses FP on a CPU without an associated FPU then
    fpu_emulator_init_fpu() initializes the task's floating point
    register state in struct thread_info such that all floating point
    register contain the bit pattern 0x7ff800007ff80000, different to
    the _init_fpu() behaviour.

  - If a task's floating point context is first accessed via ptrace then
    init_fp_ctx() initializes the floating point register state in
    struct thread_info to ~0, giving equivalent state to _init_fpu().

The _init_fpu() path has 2 separate implementations - one for r2k/r3k
style systems & one for r4k style systems. The _init_fpu() path also
requires that we be careful to clear & restore the value of the
Config5.FRE bit on modern systems in order to avoid inadvertently
triggering floating point exceptions.

None of this code is in a performance critical hot path - it runs only
the first time a task uses floating point. As such it doesn't seem to
warrant the complications of maintaining the _init_fpu() path.

Remove _init_fpu() & fpu_emulator_init_fpu(), instead using
init_fp_ctx() consistently to initialize floating point register state
in struct thread_info. Upon a task's first use of floating point this
will typically mean that we initialize state in memory & then load it
into FPU registers using _restore_fp() just as we would on a context
switch. For other paths such as __compute_return_epc_for_insn() or
mipsr2_decoder() this results in a significant simplification of the
work to be done.

Signed-off-by: Paul Burton <paul.burton@mips.com>
Patchwork: https://patchwork.linux-mips.org/patch/21002/
Cc: linux-mips@linux-mips.org
2018-11-09 10:23:13 -08:00
Linus Torvalds 977674c06b Merge branch 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus
Pull MIPS fixes from Ralf Baechle:
 "Lantiq:
    - Fix adding xbar resoures causing a panic

  Loongson3:
    - Some Loongson 3A don't identify themselves as having an FTLB so
      hardwire that knowledge into CPU probing.
    - Handle Loongson 3 TLB peculiarities in the fast path of the RDHWR
      emulation.
    - Fix invalid FTLB entries with huge page on VTLB+FTLB platforms
    - Add missing calculation of S-cache and V-cache cache-way size

  Ralink:
    - Fix typos in rt3883 pinctrl data

  Generic:
    - Force o32 fp64 support on 32bit MIPS64r6 kernels
    - Yet another build fix after the linux/sched.h changes
    - Wire up statx system call
    - Fix stack unwinding after introduction of IRQ stack
    - Fix spinlock code to build even for microMIPS with recent binutils

  SMP-CPS:
    - Fix retrieval of VPE mask on big endian CPUs"

* 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus:
  MIPS: IRQ Stack: Unwind IRQ stack onto task stack
  MIPS: c-r4k: Fix Loongson-3's vcache/scache waysize calculation
  MIPS: Flush wrong invalid FTLB entry for huge page
  MIPS: Check TLB before handle_ri_rdhwr() for Loongson-3
  MIPS: Add MIPS_CPU_FTLB for Loongson-3A R2
  MIPS: Lantiq: fix missing xbar kernel panic
  MIPS: smp-cps: Fix retrieval of VPE mask on big endian CPUs
  MIPS: Wire up statx system call
  MIPS: Include asm/ptrace.h now linux/sched.h doesn't
  MIPS: ralink: Fix typos in rt3883 pinctrl
  MIPS: End spinlocks with .insn
  MIPS: Force o32 fp64 support on 32bit MIPS64r6 kernels
2017-04-06 13:16:34 -07:00
James Hogan 0c7e2bc87e MIPS: Include asm/ptrace.h now linux/sched.h doesn't
Use of the task_pt_regs() based macros in MIPS' asm/processor.h for
accessing the user context on the kernel stack need the definition of
struct pt_regs from asm/ptrace.h. __own_fpu() in asm/fpu.h uses these
macros but implicitly depended on linux/sched.h to include asm/ptrace.h.

Since commit f780d89a0e ("sched/headers: Remove <asm/ptrace.h> from
<linux/sched.h>") however linux/sched.h no longer includes asm/ptrace.h,
so include it explicitly from asm/fpu.h where it is needed instead.

This fixes build errors such as:

./arch/mips/include/asm/fpu.h: In function '__own_fpu':
./arch/mips/include/asm/processor.h:385:31: error: invalid application of 'sizeof' to incomplete type 'struct pt_regs'
     THREAD_SIZE - 32 - sizeof(struct pt_regs))
                               ^

Fixes: f780d89a0e ("sched/headers: Remove <asm/ptrace.h> from <linux/sched.h>")
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/15386/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2017-03-08 12:08:31 +01:00
Arnd Bergmann fc69910f32 MIPS: Add missing include files
After the split of linux/sched.h, several platforms in arch/mips stopped building.

Add the respective additional #include statements to fix the problem I first
tried adding these into asm/processor.h, but ran into circular header
dependencies with that which I could not figure out.

The commit I listed as causing the problem is the branch merge, as there is
likely a combination of multiple patches in that branch.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-mips@linux-mips.org
Cc: ralf@linux-mips.org
Fixes: 1827adb11a ("Merge branch 'WIP.sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip")
Link: http://lkml.kernel.org/r/20170308072931.3836696-1-arnd@arndb.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-03-08 10:38:06 +01:00
Ingo Molnar 68db0cf106 sched/headers: Prepare for new header dependencies before moving code to <linux/sched/task_stack.h>
We are going to split <linux/sched/task_stack.h> out of <linux/sched.h>, which
will have to be picked up from other headers and a couple of .c files.

Create a trivial placeholder <linux/sched/task_stack.h> file that just
maps to <linux/sched.h> to make this patch obviously correct and
bisectable.

Include the new header in the files that are going to need it.

Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-03-02 08:42:36 +01:00
James Hogan 00fe56dca6 MIPS: Fix FPU disable with preemption
The FPU should not be left enabled after a task context switch. This
isn't usually a problem as the FPU enable bit is updated before
returning to userland, however it can potentially mask kernel bugs, and
in fact KVM assumes it won't happen and won't clear the FPU enable bit
before returning to the guest, which allows the guest to use stale FPU
context.

Interrupts and exceptions save and restore most bits of the CP0 Status
register which contains the FPU enable bit (CU1). When the kernel needs
to enable or disable the FPU (for example due to attempted FPU use by
userland, or the scheduler being invoked) both the actual Status
register and the saved value in the userland context are updated.

However this doesn't work correctly with full kernel preemption enabled,
since the FPU enable bit can be cleared from within an interrupt when
the scheduler is invoked, and only the userland context is updated, not
the interrupt context.

For example:
1) Enter kernel with FPU already enabled, TIF_USEDFPU=1, Status.CU1=1
   saved.
2) Take a timer interrupt while in kernel mode, Status.CU1=1 saved.
3) Timer interrupt invokes scheduler to preempt the task, which clears
   TIF_USEDFPU, disables the FPU in Status register (Status.CU1=0), and
   the value stored in user context from step (1), but not the interrupt
   context from step (2).
4) When the process is scheduled back in again Status.CU1=0.
5) The interrupt context from step (2) is restored, which sets
   Status.CU1=1. So from user context point of view, preemption has
   re-enabled FPU!
6) If the scheduler is invoked again (via preemption or voluntarily)
   before returning to userland, TIF_USEDFPU=0 so the FPU is not
   disabled before the task context switch.
7) The next task resumes from the context switch with FPU enabled!

The restoring of the Status register on return from interrupt/exception
is already selective about which bits to restore, leaving the interrupt
mask bits alone so enabling/disabling of CPU interrupt lines can
persist. Extend this to also leave both the CU1 bit (FPU enable) and the
FR bit (which specifies the FPU mode and gets changed with CU1). This
prevents a stale Status value being restored in step (5) above and
persisting through subsequent context switches.

Also switch to the use of definitions from asm/mipsregs.h while we're at
it.

Since this change also affects the restoration of Status register on the
path back to userland, it increases the sensitivity of the kernel to the
problem of the FPU being left enabled, allowing it to propagate to
userland, therefore a warning is also added to lose_fpu_inatomic() to
point out any future reoccurances before they do any damage.

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/12303/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2016-02-01 23:36:38 +01:00
Paul Burton 1a3d59579b MIPS: Tidy up FPU context switching
Rather than saving the scalar FP or vector context in the assembly
resume function, reuse the existing C code we have in fpu.h to do
exactly that. This reduces duplication, results in a much easier to read
resume function & should allow the compiler to optimise out more MSA
code due to is_msa_enabled()/cpu_has_msa being known-zero at compile
time for kernels without MSA support.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com>
Cc: Maciej W. Rozycki <macro@linux-mips.org>
Cc: linux-kernel@vger.kernel.org
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Markos Chandras <markos.chandras@imgtec.com>
Cc: Manuel Lauss <manuel.lauss@gmail.com>
Patchwork: https://patchwork.linux-mips.org/patch/10830/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2015-09-03 12:08:05 +02:00
Markos Chandras fcc53b5f6c MIPS: fpu.h: Allow 64-bit FPU on a 64-bit MIPS R6 CPU
Commit 6134d94923 ("MIPS: asm: fpu: Allow 64-bit FPU on MIPS32 R6")
added support for 64-bit FPU on a 32-bit MIPS R6 processor but it missed
the 64-bit CPU case leading to FPU failures when requesting FR=1 mode
(which is always the case for MIPS R6 userland) when running a 32-bit
kernel on a 64-bit CPU. We also fix the MIPS R2 case.

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Fixes: 6134d94923 ("MIPS: asm: fpu: Allow 64-bit FPU on MIPS32 R6")
Reviewed-by: Paul Burton <paul.burton@imgtec.com>
Cc: <stable@vger.kernel.org> # 4.0+
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/10734/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2015-07-19 11:31:24 +02:00
Ralf Baechle 98b0429b7a Merge branch '4.1-fp' into mips-for-linux-next 2015-04-13 16:01:37 +02:00
Maciej W. Rozycki 9b26616c8d MIPS: Respect the ISA level in FCSR handling
Define the central place the default FCSR value is set from, initialised
in `cpu_probe'.  Determine the FCSR mask applied to values written to
the register with CTC1 in the full emulation mode and via ptrace(2),
according to the ISA level of processor hardware or the writability of
bits 31:18 if actual FPU hardware is used.

Software may rely on FCSR bits whose functions our emulator does not
implement, so it should not allow them to be set or software may get
confused.  For ptrace(2) it's just sanity.

[ralf@linux-mips.org: Fixed double inclusion of <asm/current.h>.]

Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/9711/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2015-04-08 01:10:37 +02:00
Paul Burton 84ab45b338 MIPS: disable FPU if the mode is unsupported
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: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/9167/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2015-03-27 19:42:47 +01:00
James Hogan acaf6a97d6 MIPS: lose_fpu(): Disable FPU when MSA enabled
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: 33c771ba5c ("MIPS: save/disable MSA in lose_fpu")
Signed-off-by: James 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: Ralf Baechle <ralf@linux-mips.org>
2015-03-27 19:39:42 +01:00
Linus Torvalds a135c717d5 Merge branch 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus
Pull MIPS updates from Ralf Baechle:
 "This is the main pull request for MIPS:

   - a number of fixes that didn't make the 3.19 release.

   - a number of cleanups.

   - preliminary support for Cavium's Octeon 3 SOCs which feature up to
     48 MIPS64 R3 cores with FPU and hardware virtualization.

   - support for MIPS R6 processors.

     Revision 6 of the MIPS architecture is a major revision of the MIPS
     architecture which does away with many of original sins of the
     architecture such as branch delay slots.  This and other changes in
     R6 require major changes throughout the entire MIPS core
     architecture code and make up for the lion share of this pull
     request.

   - finally some preparatory work for eXtendend Physical Address
     support, which allows support of up to 40 bit of physical address
     space on 32 bit processors"

     [ Ahh, MIPS can't leave the PAE brain damage alone.  It's like
       every CPU architect has to make that mistake, but pee in the snow
       by changing the TLA.  But whether it's called PAE, LPAE or XPA,
       it's horrid crud   - Linus ]

* 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus: (114 commits)
  MIPS: sead3: Corrected get_c0_perfcount_int
  MIPS: mm: Remove dead macro definitions
  MIPS: OCTEON: irq: add CIB and other fixes
  MIPS: OCTEON: Don't do acknowledge operations for level triggered irqs.
  MIPS: OCTEON: More OCTEONIII support
  MIPS: OCTEON: Remove setting of processor specific CVMCTL icache bits.
  MIPS: OCTEON: Core-15169 Workaround and general CVMSEG cleanup.
  MIPS: OCTEON: Update octeon-model.h code for new SoCs.
  MIPS: OCTEON: Implement DCache errata workaround for all CN6XXX
  MIPS: OCTEON: Add little-endian support to asm/octeon/octeon.h
  MIPS: OCTEON: Implement the core-16057 workaround
  MIPS: OCTEON: Delete unused COP2 saving code
  MIPS: OCTEON: Use correct instruction to read 64-bit COP0 register
  MIPS: OCTEON: Save and restore CP2 SHA3 state
  MIPS: OCTEON: Fix FP context save.
  MIPS: OCTEON: Save/Restore wider multiply registers in OCTEON III CPUs
  MIPS: boot: Provide more uImage options
  MIPS: Remove unneeded #ifdef __KERNEL__ from asm/processor.h
  MIPS: ip22-gio: Remove legacy suspend/resume support
  mips: pci: Add ifdef around pci_proc_domain
  ...
2015-02-21 19:41:38 -08:00
Markos Chandras 6134d94923 MIPS: asm: fpu: Allow 64-bit FPU on MIPS32 R6
MIPS32 R6 has a 64-bit FPU so add the necessary MIPS R6
definition.

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
2015-02-17 15:37:38 +00:00
Ralf Baechle d33e6fe3ca MIPS: FRE: Use set/clear_c0_config5 instead of open coded sequences.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2015-01-13 15:53:08 +01:00
Ralf Baechle b0c34f6155 MIPS: Do not fiddle with FRE unless FRE is actually available.
Commit 4227a2d4ef (MIPS: Support for hybrid
FPRs) changes the kernel to execute read_c0_config5() even on processors
that don't have a Config5 register.  According to the arch spec the
behaviour of trying to read or write this register is UNDEFINED where this
register doesn't exist, that is merely looking at this register is
already cruel because that might kill a kitten.

In case of Qemu older than v2.2 Qemu has elected to implement this
UNDEFINED behaviour by taking a RI exception - which then fries the
kernel:

[...]
Freeing YAMON memory: 956k freed
Freeing unused kernel memory: 240K (80674000 - 806b0000)
Reserved instruction in kernel code[#1]:
CPU: 0 PID: 1 Comm: init Not tainted 3.18.0-rc6-00058-g4227a2d #26
task: 86047588 ti: 86048000 task.ti: 86048000
$ 0   : 00000000 77a638cc 00000000 00000000
[...]

For qemu v2.2.0 commit f31b035a9f10dc9b57f01c426110af845d453ce2
(target-mips: correctly handle access to unimplemented CP0 register)
changed the behaviour to returning zero on read and ignoring writes
which more matches how typical hardware implementations actually behave.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2015-01-13 15:53:08 +01:00
Paul Burton 4227a2d4ef MIPS: Support for hybrid FPRs
Hybrid FPRs is a scheme where scalar FP registers are 64b wide, but
accesses to odd indexed single registers use bits 63:32 of the
preceeding even indexed 64b register. In this mode all FP code
except that built for the plain FP64 ABI can execute correctly. Most
notably a combination of FP64A & FP32 code can execute correctly,
allowing for existing FP32 binaries to be linked with new FP64A binaries
that can make use of 64 bit FP & MSA.

Hybrid FPRs are implemented by setting both the FR & FRE bits, trapping
& emulating single precision FP instructions (via Reserved Instruction
exceptions) whilst allowing others to execute natively. It therefore has
a penalty in terms of execution speed, and should only be used when no
fully native mode can be. As more binaries are recompiled to use either
the FPXX or FP64(A) ABIs, the need for hybrid FPRs should diminish.
However in the short to mid term it allows for a gradual transition
towards that world, rather than a complete ABI break which is not
feasible for some users & not desirable for many.

A task will be executed using the hybrid FPR scheme when its
TIF_HYBRID_FPREGS flag is set & TIF_32BIT_FPREGS is clear. A further
patch will set the flags as necessary, this patch simply adds the
infrastructure necessary for the hybrid FPR mode to work.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/7683/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2014-11-24 07:45:07 +01:00
Manuel Lauss 842dfc11ea MIPS: Fix build with binutils 2.24.51+
Starting with version 2.24.51.20140728 MIPS binutils complain loudly
about mixing soft-float and hard-float object files, leading to this
build failure since GCC is invoked with "-msoft-float" on MIPS:

{standard input}: Warning: .gnu_attribute 4,3 requires `softfloat'
  LD      arch/mips/alchemy/common/built-in.o
mipsel-softfloat-linux-gnu-ld: Warning: arch/mips/alchemy/common/built-in.o
 uses -msoft-float (set by arch/mips/alchemy/common/prom.o),
 arch/mips/alchemy/common/sleeper.o uses -mhard-float

To fix this, we detect if GAS is new enough to support "-msoft-float" command
option, and if it does, we can let GCC pass it to GAS;  but then we also need
to sprinkle the files which make use of floating point registers with the
necessary ".set hardfloat" directives.

Signed-off-by: Manuel Lauss <manuel.lauss@gmail.com>
Cc: Linux-MIPS <linux-mips@linux-mips.org>
Cc: Matthew Fortune <Matthew.Fortune@imgtec.com>
Cc: Markos Chandras <Markos.Chandras@imgtec.com>
Cc: Maciej W. Rozycki <macro@linux-mips.org>
Patchwork: https://patchwork.linux-mips.org/patch/8355/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2014-11-07 15:07:36 +01:00
Paul Burton 762a1f4388 MIPS: disable preemption whilst initialising MSA
Preemption must be disabled throughout the process of enabling the FPU,
enabling MSA & initialising the vector registers. Without doing so it
is possible to lose the FPU or MSA whilst initialising them causing
that initialisation to fail.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/7307/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2014-08-02 00:06:44 +02:00
Paul Burton 33c771ba5c MIPS: save/disable MSA in lose_fpu
The kernel depends upon MSA never being enabled when the FPU is not, a
condition which is currently violated in a few places (whilst saving
sigcontext, following mips_cpu_save). Catch all the problem cases by
disabling MSA in lose_fpu, after saving context if necessary.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/7302/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2014-08-02 00:06:43 +02:00
Ralf Baechle e0cc3a42eb MIPS: math-emu: Inline fpu_emulator_init_fpu()
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2014-05-23 15:12:37 +02:00
Ralf Baechle ade63aada7 Merge branch '3.14-fixes' into mips-for-linux-next 2014-03-31 18:17:33 +02:00
Paul Burton bbd426f542 MIPS: Simplify FP context access
This patch replaces the fpureg_t typedef with a "union fpureg" enabling
easier access to 32 & 64 bit values. This allows the access macros used
in cp1emu.c to be simplified somewhat. It will also make it easier to
expand the width of the FP registers as will be done in a future
patch in order to support the 128 bit registers introduced with MSA.

No behavioural change is intended by this patch.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Reviewed-by: Qais Yousef <qais.yousef@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6532/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2014-03-26 23:09:09 +01:00
Paul Bolle f5868f05dc MIPS: Replace CONFIG_MIPS64 and CONFIG_MIPS32_R2
Commit 597ce1723e ("MIPS: Support for 64-bit FP with O32 binaries")
introduced references to two undefined Kconfig macros. CONFIG_MIPS32_R2
should clearly be replaced with CONFIG_CPU_MIPS32_R2. And CONFIG_MIPS64
should be replaced with CONFIG_64BIT.

Signed-off-by: Paul Bolle <pebolle@tiscali.nl>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/6522/
Tested-by: Aaro Koskinen <aaro.koskinen@iki.fi>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2014-03-14 17:49:16 +01:00
Aaro Koskinen 97b8b16bfc MIPS: fpu.h: Fix build when CONFIG_BUG is not set
__enable_fpu produces a build failure when CONFIG_BUG is not set:

In file included from arch/mips/kernel/cpu-probe.c:24:0:
arch/mips/include/asm/fpu.h: In function '__enable_fpu':
arch/mips/include/asm/fpu.h:77:1: error: control reaches end of non-void function [-Werror=return-type]

This is regression introduced in 3.14-rc1. Fix that.

Signed-off-by: Aaro Koskinen <aaro.koskinen@iki.fi>
Acked-by: Paul Burton <paul.burton@imgtec.com>
Cc: John Crispin <blogic@openwrt.org>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6504/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2014-02-06 13:42:43 +01:00
Paul Burton 597ce1723e MIPS: Support for 64-bit FP with O32 binaries
CPUs implementing MIPS32 R2 may include a 64-bit FPU, just as MIPS64 CPUs
do. In order to preserve backwards compatibility a 64-bit FPU will act
like a 32-bit FPU (by accessing doubles from the least significant 32
bits of an even-odd pair of FP registers) when the Status.FR bit is
zero, again just like a mips64 CPU. The standard O32 ABI is defined
expecting a 32-bit FPU, however recent toolchains support use of a
64-bit FPU from an O32 MIPS32 executable. When an ELF executable is
built to use a 64-bit FPU a new flag (EF_MIPS_FP64) is set in the ELF
header.

With this patch the kernel will check the EF_MIPS_FP64 flag when
executing an O32 binary, and set Status.FR accordingly. The addition
of O32 64-bit FP support lessens the opportunity for optimisation in
the FPU emulator, so a CONFIG_MIPS_O32_FP64_SUPPORT Kconfig option is
introduced to allow this support to be disabled for those that don't
require it.

Inspired by an earlier patch by Leonid Yegoshin, but implemented more
cleanly & correctly.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: Paul Burton <paul.burton@imgtec.com>
Patchwork: https://patchwork.linux-mips.org/patch/6154/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2014-01-13 23:40:56 +01:00
Paul Burton 56a22d21bf MIPS: Remove unused {en,dis}able_fpu macros
These macros are not used anywhere in the kernel. Remove them.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6111/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2014-01-13 23:40:56 +01:00
Ralf Baechle 7034228792 MIPS: Whitespace cleanup.
Having received another series of whitespace patches I decided to do this
once and for all rather than dealing with this kind of patches trickling
in forever.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2013-02-01 10:00:22 +01:00
Ralf Baechle 137f6f3e28 MIPS: Cleanup signal code initialization
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Patchwork: http://patchwork.linux-mips.org/patch/709/
2009-12-17 01:57:32 +00:00
Ralf Baechle 384740dc49 MIPS: Move headfiles to new location below arch/mips/include
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2008-10-11 16:18:52 +01:00