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path: root/arch/mips/include/asm/switch_to.h
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2015-09-03MIPS: Tidy up FPU context switchingPaul Burton1-17/+4
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>
2015-09-03MIPS: Get rid of finish_arch_switch().Ralf Baechle1-25/+23
MIPS was using finish_arch_switch() as a hook to restore and initialize CPU context for all threads, even newly created kernel and user threads. This is however entirely solvable within switch_to() so get rid of finish_arch_switch() which is in the way of scheduler cleanups. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2015-06-10MIPS: MSA: bugfix - disable MSA correctly for new threads/processes.Ralf Baechle1-1/+1
Due to the slightly odd way that new threads and processes start execution when scheduled for the very first time they were bypassing the required disable_msa call. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2015-02-17MIPS: Make use of the ERETNC instruction on MIPS R6Markos Chandras1-3/+6
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>
2014-08-26MIPS: COP2: CPP macro safety fixes.Ralf Baechle1-2/+2
- Don't pass things to macros that couldn't be dereferences if that macro was actually a function. - Don't use empty function-like macros. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2014-03-27MIPS: Basic MSA context switching supportPaul Burton1-5/+17
This patch adds support for context switching the MSA vector registers. These 128 bit vector registers are aliased with the FP registers - an FP register accesses the least significant bits of the vector register with which it is aliased (ie. the register with the same index). Due to both this & the requirement that the scalar FPU must be 64-bit (FR=1) if enabled at the same time as MSA the kernel will enable MSA & scalar FP at the same time for tasks which use MSA. If we restore the MSA vector context then we might as well enable the scalar FPU since the reason it was left disabled was to allow for lazy FP context restoring - but we just restored the FP context as it's a subset of the vector context. If we restore the FP context and have previously used MSA then we have to restore the whole vector context anyway (see comment in enable_restore_fp_context for details) so similarly we might as well enable MSA. Thus if a task does not use MSA then it will continue to behave as without this patch - the scalar FP context will be saved & restored as usual. But if a task executes an MSA instruction then it will save & restore the vector context forever more. Signed-off-by: Paul Burton <paul.burton@imgtec.com> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/6431/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2014-01-25MIPS: clean up resume declarationPaul Burton1-4/+12
This patch cleans up the declaration of the resume function by replacing void pointers with their correct types. The irrelevant & incorrect comment preceeding the resume function is replaced by one documenting its function. Signed-off-by: Paul Burton <paul.burton@imgtec.com> Reviewed-by: Qais Yousef <qais.yousef@imgtec.com> Signed-off-by: John Crispin <blogic@openwrt.org> Patchwork: http://patchwork.linux-mips.org/patch/6146/
2013-06-13MIPS: Move cop2 save/restore to switch_to()Jayachandran C1-1/+18
Move the common code for saving and restoring platform specific COP2 registers to switch_to(). This will make supporting new platforms (like Netlogic XLP) easier. The platform specific COP2 definitions are to be specified in asm/processor.h and in asm/cop2.h. Signed-off-by: Jayachandran C <jchandra@broadcom.com> Cc: linux-mips@linux-mips.org Cc: ddaney.cavm@gmail.com Patchwork: https://patchwork.linux-mips.org/patch/5411/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2013-02-01MIPS: Whitespace cleanup.Ralf Baechle1-2/+2
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>
2012-07-19MIPS: Fix race condition with FPU thread task flag during context switch.Leonid Yegoshin1-2/+4
[ralf@linux-mips.org: Cosmetic changes; also fixed up r2300_switch.S and octeon_switch.S which needed similar modifications.] Signed-off-by: Leonid Yegoshin <yegoshin@mips.com> Signed-off-by: Steven J. Hill <sjhill@mips.com> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/3784/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2012-03-28Disintegrate asm/system.h for MIPSDavid Howells1-0/+85
Disintegrate asm/system.h for MIPS. Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Ralf Baechle <ralf@linux-mips.org> cc: linux-mips@linux-mips.org