Commit Graph

1933 Commits

Author SHA1 Message Date
David Daney 151f9148d1 MIPS: Remove unneeded #ifdef __KERNEL__ from asm/processor.h
Signed-off-by: David Daney <david.daney@cavium.com>
Signed-off-by: Aleksey Makarov <aleksey.makarov@auriga.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/8737/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2015-02-20 14:14:52 +01:00
Lars-Peter Clausen fa75da8ecd MIPS: ip22-gio: Remove legacy suspend/resume support
There are currently no gio device drivers that implement suspend/resume
and this patch removes the bus specific legacy suspend and resume callbacks.
This will allow us to eventually remove struct bus_type legacy suspend and
resume support altogether.

gio device drivers wanting to implement suspend and resume can use dev PM
ops which will work out of the box without further modifications necessary.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Acked-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/8920/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2015-02-20 13:30:55 +01:00
Zubair Lutfullah Kakakhel 6fb8a163fc mips: pci: Add ifdef around pci_proc_domain
Without these, there are multiple definitions of pci_proc_domain()
and pci_domain_nr() if linux/pci.h and asm/pci.h are included.

Add #ifdefs around them

Signed-off-by: Zubair Lutfullah Kakakhel <Zubair.Kakakhel@imgtec.com>
Reviewed-by: Markos Chandras <Markos.Chandras@imgtec.com>
Cc: Markos.Chandras@imgtec.com
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/8670/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2015-02-20 13:16:14 +01:00
Steven J. Hill a5770df095 MIPS: Add set/clear CP0 macros for PageGrain register
Build set and clear macros for the PageGrain register.

Signed-off-by: Steven J. Hill <Steven.Hill@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/9289/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2015-02-20 12:55:18 +01:00
Steven J. Hill 05f9883a28 MIPS: Usage and cosmetic cleanups of page table bits.
* Clean up white spaces and tabs.
   * Get rid of remaining hardcoded values for calculating
     shifts and masks.
   * Get rid of redundant macro values.
   * Do not use page table bits directly in #ifdef's.

Signed-off-by: Steven J. Hill <Steven.Hill@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/9287/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2015-02-19 22:15:59 +01:00
Ralf Baechle 661af35e5f Merge branch 'mipsr6-for-3.20' of git://git.linux-mips.org/pub/scm/mchandras/linux into mips-for-linux-next 2015-02-19 16:00:34 +01:00
Petr Malat 8cb48fe169 MIPS: Provide correct siginfo_t.si_stime
Provide correct siginfo_t.si_stime on MIPS64

Bug description:
MIPS version of copy_siginfo() is not aware of alignment on platforms with
64-bit long integers, which leads to an incorrect si_stime passed to signal
handlers, because the last element (si_stime) of _sifields._sigchld is not
copied. If _MIPS_SZLONG is 64, then the _sifields starts at the offset of
4 * sizeof(int).

Patch description:
Use the generic copy_siginfo, which doesn't have this problem.

Signed-off-by: Petr Malat <oss@malat.biz>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/8671/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2015-02-19 13:47:46 +01:00
Markos Chandras 46490b5725 MIPS: kernel: elf: Improve the overall ABI and FPU mode checks
The previous implementation did not cover all possible FPU combinations
and it silently allowed ABI incompatible objects to be loaded with the
wrong ABI. For example, the previous logic would set the FP_64 ABI as
the matching ABI for an FP_XX object combined with an FP_64A object.
This was wrong, and the matching ABI should have been FP_64A.
The previous logic is now replaced with a new one which determines
the appropriate FPU mode to be used rather than the FP ABI. This has
the advantage that the entire logic is much simpler since it is the FPU
mode we are interested in rather than the FP ABI resulting to code
simplifications. This also removes the now obsolete FP32XX_HYBRID_FPRS
option.

Cc: Matthew Fortune <Matthew.Fortune@imgtec.com>
Cc: Paul Burton <paul.burton@imgtec.com>
Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
2015-02-17 15:37:39 +00:00
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
Markos Chandras e0d32f33e6 MIPS: Handle MIPS IV, V and R2 FPU instructions on MIPS R6 as well
MIPS R2 FPU instructions are also present in MIPS R6 so amend the
preprocessor definitions to take MIPS R6 into consideration.

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
2015-02-17 15:37:37 +00:00
Markos Chandras 7c151d3d5d MIPS: Make use of the ERETNC instruction on MIPS R6
The ERETNC instruction, introduced in MIPS R5, is similar to the ERET
one, except it does not clear the LLB bit in the LLADDR register.
This feature is necessary to safely emulate R2 LL/SC instructions.
However, on context switches, we need to clear the LLAddr/LLB bit
in order to make sure that an SC instruction from the new thread
will never succeed if it happens to interrupt an LL operation on the
same address from the previous thread.

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
2015-02-17 15:37:37 +00:00
Leonid Yegoshin b0a668fb20 MIPS: kernel: mips-r2-to-r6-emul: Add R2 emulator for MIPS R6
MIPS R6 removed quite a few R2 instructions. However, there
is plenty of <R6 userland code so we add an in-kernel emulator
so we can still be able to execute all R2 userland out there.

The emulator comes with a handy debugfs under /mips/ directory
(r2-emul-stats) to provide some basic statistics of the
instructions that are being emulated.

Below are some statistics from booting a minimal buildroot image:

Instruction     Total   BDslot
------------------------------
movs            236969  0
hilo            56686   0
muls            55279   0
divs            10941   0
dsps            0       0
bops            1       0
traps           0       0
fpus            0       0
loads           214981  17
stores          103364  0
llsc            56898   0
dsemul          150418  0
jr              370158
bltzl           43
bgezl           1594
bltzll          0
bgezll          0
bltzal          39
bgezal          39
beql            14503
bnel            138741
blezl           0
bgtzl           3988

Signed-off-by: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com>
Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
2015-02-17 15:37:37 +00:00
Markos Chandras b55b9e2715 MIPS: asm: mipsregs: Add support for the LLADDR register
If Config5/LLB is set in the core, then software can write the LLB
bit in the LLADDR register.

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
2015-02-17 15:37:36 +00:00
Markos Chandras 5aed9da128 MIPS: Add LLB bit and related feature for the Config 5 CP0 register
The LLBIT (bit 4) in the Config5 CP0 register indicates the software
availability of the Load-Linked bit. This bit is only set by hardware
and it has the following meaning:

0: LLB functionality is not supported
1: LLB functionality is supported. The following feature are also
supported:

- ERETNC instruction. Similar to ERET but it does not clear the LLB
bit in the LLAddr register.
- CP0 LLAddr/LLB bit must be set
- LLbit is software accessible through the LLAddr[0]

This will be used later on to emulate R2 LL/SC instructions.

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
2015-02-17 15:37:36 +00:00
Markos Chandras 28d6f93d20 MIPS: Emulate the new MIPS R6 BNEZC and JIALC instructions
MIPS R6 uses the <R6 sdc2 opcode for the new BNEZC and JIALC instructions

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
2015-02-17 15:37:35 +00:00
Markos Chandras 69b9a2fd05 MIPS: Emulate the new MIPS R6 BEQZC and JIC instructions
MIPS R6 uses the <R6 ldc2 opcode for the new BEQZC and JIC instructions

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
2015-02-17 15:37:35 +00:00
Markos Chandras 84fef63012 MIPS: Emulate the new MIPS R6 BALC instruction
MIPS R6 uses the <R6 swc2 opcode for the new BALC instructions.

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
2015-02-17 15:37:35 +00:00
Markos Chandras 10d962d534 MIPS: Emulate the new MIPS R6 BNVC, BNEC and BNEZLAC instructions
MIPS R6 uses the <R6 DADDI opcode for the new BNVC, BNEC and
BNEZLAC instructions.

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
2015-02-17 15:37:34 +00:00
Markos Chandras c893ce38b2 MIPS: Emulate the new MIPS R6 BOVC, BEQC and BEQZALC instructions
MIPS R6 uses the <R6 ADDI opcode for the new BOVC, BEQC and
BEQZALC instructions.

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
2015-02-17 15:37:34 +00:00
Markos Chandras 8467ca0122 MIPS: Emulate the new MIPS R6 branch compact (BC) instruction
MIPS R6 uses the <R6 LWC2 opcode for the new BC instruction.

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
2015-02-17 15:37:34 +00:00
Markos Chandras c8a34581ec MIPS: Emulate the BC1{EQ,NE}Z FPU instructions
MIPS R6 introduced the following two branch instructions for COP1:

BC1EQZ: Branch if Cop1 (FPR) Register Bit 0 is Equal to Zero
BC1NEZ: Branch if Cop1 (FPR) Register Bit 0 is Not Equal to Zero

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
2015-02-17 15:37:32 +00:00
Markos Chandras 5f9f41c474 MIPS: kernel: Prepare the JR instruction for emulation on MIPS R6
The MIPS R6 JR instruction is an alias to the JALR one, so it may
need emulation for non-R6 userlands.

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
2015-02-17 15:37:31 +00:00
Leonid Yegoshin 207083b1da MIPS: kernel: r4k_switch: Add support for MIPS R6
Add the MIPS R6 related preprocessor definitions for save/restore
FPU related functions. We also set the appropriate ISA level
so the final return instruction "jr ra" will produce the correct
opcode on R6.

Signed-off-by: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com>
Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
2015-02-17 15:37:27 +00:00
Markos Chandras 515a6393db MIPS: kernel: proc: Add MIPS R6 support to /proc/cpuinfo
Print 'mips64r6' and/or 'mips32r6' if the kernel is running on
a MIPS R6 core.

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
2015-02-17 15:37:26 +00:00
Markos Chandras 82e7ce8149 MIPS: asm: local: Set the appropriate ISA level for MIPS R6
MIPS R6 changed the opcodes for LL/SC instructions so we need to set
the appropriate ISA level.

Cc: Matthew Fortune <Matthew.Fortune@imgtec.com>
Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
2015-02-17 15:37:24 +00:00
Markos Chandras 5753762cbd MIPS: asm: spinlock: Replace "sub" instruction with "addiu"
"sub $reg, imm" is not a real MIPS instruction. The assembler can
replace that with "addi $reg, -imm". However, addi has been removed
from R6, so we replace the "sub" instruction with the "addiu" one.

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
2015-02-17 15:37:23 +00:00
Markos Chandras 1922c356ab MIPS: asm: futex: Set the appropriate ISA level for MIPS R6
MIPS R6 changed the opcodes for LL/SC instructions so we need to set
the appropriate ISA level.

Cc: Matthew Fortune <Matthew.Fortune@imgtec.com>
Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
2015-02-17 15:37:23 +00:00
Markos Chandras 87a927eff4 MIPS: asm: bitops: Update ISA constraints for MIPS R6 support
MIPS R6 changed the opcodes for LL/SC instructions so we need to set
the correct ISA level.

Cc: Matthew Fortune <Matthew.Fortune@imgtec.com>
Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
2015-02-17 15:37:22 +00:00
Markos Chandras 0038df2240 MIPS: asm: atomic: Update ISA constraints for MIPS R6 support
MIPS R6 changed the opcodes for LL/SC instructions so we need to
set the correct ISA level.

Cc: Matthew Fortune <Matthew.Fortune@imgtec.com>
Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
2015-02-17 15:37:22 +00:00
Markos Chandras fa998ebbc0 MIPS: asm: cmpxchg: Update ISA constraints for MIPS R6 support
MIPS R6 changed the opcodes for LL/SC instructions so we need to set
the correct ISA.

Cc: Matthew Fortune <Matthew.Fortune@imgtec.com>
Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
2015-02-17 15:37:22 +00:00
Markos Chandras 123e4b3bbc MIPS: Use the new "ZC" constraint for MIPS R6
GCC versions supporting MIPS R6 use the ZC constraint to enforce a
9-bit offset for MIPS R6. We will use that for all MIPS R6 LL/SC
instructions.

Cc: Matthew Fortune <Matthew.Fortune@imgtec.com>
Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
2015-02-17 15:37:21 +00:00
Markos Chandras 94bfb75ace MIPS: asm: Rename GCC_OFF12_ASM to GCC_OFF_SMALL_ASM
The GCC_OFF12_ASM macro is used for 12-bit immediate constrains
but we will also use it for 9-bit constrains on MIPS R6 so we
rename it to something more appropriate.

Cc: Maciej W. Rozycki <macro@linux-mips.org>
Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
2015-02-17 15:37:21 +00:00
Markos Chandras a7e07b1ae5 MIPS: asm: spram: Add new symbol for MIPS scratch pad storage
MIPS R6, just like MIPS R2, have scratch pad storage, so add a new
symbol which is selected by MIPS R2 and R6.

Link: http://www.linux-mips.org/archives/linux-mips/2015-01/msg00389.html
Cc: Maciej W. Rozycki <macro@linux-mips.org>
Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
2015-02-17 15:37:20 +00:00
Markos Chandras 934c79231c MIPS: asm: r4kcache: Add MIPS R6 cache unroll functions
MIPS R6 changed the 'cache' instruction opcode and reduced the
offset field to 8 bits. This means we now have to adjust the
base register every 256 bytes and as a result of which we can
no longer use the previous cache functions.

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
2015-02-17 15:37:20 +00:00
Markos Chandras 8716a76356 MIPS: asm: irqflags: Add MIPS R6 related definitions
Add the MIPS R6 related definitions to the IRQ related macros

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
2015-02-17 15:37:20 +00:00
Markos Chandras f52fca9713 MIPS: asm: hazards: Add MIPSR6 definitions
Add the MIPSR6 related definitions to MIPS hazards

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
2015-02-17 15:37:19 +00:00
Leonid Yegoshin 34c56fc1c1 MIPS: asm: cpu: Add MIPSR6 ISA definitions
Add MIPS R6 to the ISA definitions

Signed-off-by: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com>
Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
2015-02-17 15:37:19 +00:00
Markos Chandras 4e0748f5be MIPS: Use generic checksum functions for MIPS R6
The following instructions have been removed from MIPS R6

ulw, ulh, swl, lwr, lwl, swr.

However, all of them are used in the MIPS specific checksum implementation.
As a result of which, we will use the generic checksum on MIPS R6

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
2015-02-17 15:37:19 +00:00
Markos Chandras 98a833c1fa MIPS: asm: asmmacro: Replace "add" instructions with "addu"
The "add" instruction is actually a macro in binutils and depending on
the size of the immediate it can expand to an "addi" instruction.
However, the "addi" instruction traps on overflows which is not
something we want on address calculation.

Link: http://www.linux-mips.org/archives/linux-mips/2015-01/msg00121.html
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: Maciej W. Rozycki <macro@linux-mips.org>
Cc: <stable@vger.kernel.org> # v3.15+
Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
2015-02-17 15:37:18 +00:00
Leonid Yegoshin 226da55f48 MIPS: asm: asmmacro: Add MIPS R6 support to the simple EI/DI variants
EI/DI instructions are available in MIPS R6 so add the needed
definitions.

Signed-off-by: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com>
Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
2015-02-17 15:37:18 +00:00
Leonid Yegoshin 6a0e9865b9 MIPS: asm: stackframe: Do not preserve the HI/LO registers on MIPS R6
The HI/LO registers have been removed from MIPS R6. Instructions
such as MULT and DIV have been replaced with a new pair of
instructions for the HI/LO operations for example:

MULT -> MUL, MUH
DIV -> DIV, MOD

So we avoid preserving the pre-R6 HI/LO registers in MIPS R6

Signed-off-by: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com>
Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
2015-02-17 15:37:17 +00:00
Leonid Yegoshin b840a82c54 MIPS: asm: module: define MODULE_PROC_FAMILY for MIPS R6
Define the MODULE_PROC_FAMILY for the MIPS R6 ISA.

Signed-off-by: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com>
Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
2015-02-17 15:37:17 +00:00
Markos Chandras be5136988e MIPS: asm: compiler: Add new macros to set ISA and arch asm annotations
There are certain places where the code uses .set mips32 or .set mips64
or .set arch=r4000. In preparation of MIPS R6 support, and in order to
use as less #ifdefs as possible, we define new macros to set similar
annotations for MIPS R6.

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
2015-02-17 15:37:14 +00:00
Leonid Yegoshin a168b8f1cd MIPS: mm: Add MIPS R6 instruction encodings
MIPS R6 defines new opcodes for ll, sc, cache and pref instructions
so we need to take these into consideration in the micro-assembler.

Signed-off-by: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com>
Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
2015-02-16 14:02:50 +00:00
Leonid Yegoshin 4695089f03 MIPS: Add cases for CPU_QEMU_GENERIC
Add a CPU_QEMU_GENERIC case to various switch statements.

Signed-off-by: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com>
Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
2015-02-16 10:01:24 +00:00
Leonid Yegoshin aca5721e95 MIPS: Add generic QEMU PRid and cpu type identifiers
Latest versions of QEMU added support for mips32r6-generic and
mips64r6-generic cpu types so add related definitions in preparation
of MIPS R6 support. This is also used for QEMU R2 generic cpus.

Signed-off-by: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com>
Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
2015-02-16 10:01:24 +00:00
Markos Chandras ed4cbc81ad MIPS: HTW: Prevent accidental HTW start due to nested htw_{start, stop}
activate_mm() and switch_mm() call get_new_mmu_context() which in turn
can enable the HTW before the entryhi is changed with the new ASID.
Since the latter will enable the HTW in local_flush_tlb_all(),
then there is a small timing window where the HTW is running with the
new ASID but with an old pgd since the TLBMISS_HANDLER_SETUP_PGD
hasn't assigned a new one yet. In order to prevent that, we introduce a
simple htw counter to avoid starting HTW accidentally due to nested
htw_{start,stop}() sequences. Moreover, since various IPI calls can
enforce TLB flushing operations on a different core, such an operation
may interrupt another htw_{stop,start} in progress leading inconsistent
updates of the htw_seq variable. In order to avoid that, we disable the
interrupts whenever we update that variable.

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Cc: <stable@vger.kernel.org> # 3.17+
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/9118/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2015-02-16 10:55:26 +01:00
Markos Chandras fde3538a8a MIPS: asm: pgtable: Prevent HTW race when updating PTEs
Whenever we modify a page table entry, we need to ensure that the HTW
will not fetch a stable entry. And for that to happen we need to ensure
that HTW is stopped before we modify the said entry otherwise the HTW
may already be in the process of reading that entry and fetching the
old information. As a result of which, we replace the htw_reset() calls
with htw_{stop,start} in more appropriate places. This also removes the
remaining users of htw_reset() and as a result we drop that macro

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Cc: <stable@vger.kernel.org> # 3.17+
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/9116/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2015-02-16 10:55:26 +01:00
Markos Chandras 461d1597ff MIPS: asm: pgtable: Add c0 hazards on HTW start/stop sequences
When we use htw_{start,stop}() outside of htw_reset(), we need
to ensure that c0 changes have been propagated properly before
we attempt to continue with subsequence memory operations.

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Cc: <stable@vger.kernel.org> # 3.17+
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/9114/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2015-02-16 10:55:26 +01:00
Paul Burton 9791554b45 MIPS,prctl: add PR_[GS]ET_FP_MODE prctl options for MIPS
Userland code may be built using an ABI which permits linking to objects
that have more restrictive floating point requirements. For example,
userland code may be built to target the O32 FPXX ABI. Such code may be
linked with other FPXX code, or code built for either one of the more
restrictive FP32 or FP64. When linking with more restrictive code, the
overall requirement of the process becomes that of the more restrictive
code. The kernel has no way to know in advance which mode the process
will need to be executed in, and indeed it may need to change during
execution. The dynamic loader is the only code which will know the
overall required mode, and so it needs to have a means to instruct the
kernel to switch the FP mode of the process.

This patch introduces 2 new options to the prctl syscall which provide
such a capability. The FP mode of the process is represented as a
simple bitmask combining a number of mode bits mirroring those present
in the hardware. Userland can either retrieve the current FP mode of
the process:

  mode = prctl(PR_GET_FP_MODE);

or modify the current FP mode of the process:

  err = prctl(PR_SET_FP_MODE, new_mode);

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: Matthew Fortune <matthew.fortune@imgtec.com>
Cc: Markos Chandras <markos.chandras@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/8899/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2015-02-12 12:30:29 +01:00