[PATCH v7 0/5] riscv: Add support to no-FPU systems

Alan Kao alankao at andestech.com
Wed Oct 3 22:30:42 PDT 2018


On Thu, Sep 06, 2018 at 02:45:04AM -0700, Palmer Dabbelt wrote:
> On Sun, 26 Aug 2018 18:07:50 PDT (-0700), alankao at andestech.com wrote:
> >This patchset adds an option, CONFIG_FPU, to enable/disable floating-
> >point procedures.
> >
> >Kernel's new behavior will be as follows:
> >
> >* with CONFIG_FPU=y
> >  All FPU codes are reserved.  If no FPU is found during booting, a
> >  global flag will be set, and those functions will be bypassed with
> >  condition check to that flag.
> >
> >* with CONFIG_FPU=n
> >  No floating-point instructions in kernel and all related settings
> >  are excluded.
> >
> >Changes in v7:
> > - Remove "fd" attribute from KBUILD_CFLAGS.
> >
> >Changes in v6 (PATCH 0005 only):
> > - Make the flag checking neater.
> >
> >Changes in v5:
> > - Invert the polarity of checking flag from no_fpu to has_fpu.
> >
> >Changes in v4:
> > - Append a new patch to detect existence of FPU and followups.
> > - Add SPDX header to newly created fpu.S.
> > - Fix a build error, sorry for that.
> > - Fix wording, style, etc.
> >
> >Changes in v3:
> > - Refactor the whole patch into independent ones.
> >
> >Changes in v2:
> > - Various code cleanups and style fixes.
> >
> >
> >Alan Kao (5):
> >  Extract FPU context operations from entry.S
> >  Refactor FPU code in signal setup/return procedures
> >  Cleanup ISA string setting
> >  Allow to disable FPU support
> >  Auto-detect whether a FPU exists
> >
> > arch/riscv/Kconfig                 |   9 +++
> > arch/riscv/Makefile                |  19 +++---
> > arch/riscv/include/asm/switch_to.h |  12 +++-
> > arch/riscv/kernel/Makefile         |   1 +
> > arch/riscv/kernel/cpufeature.c     |   8 +++
> > arch/riscv/kernel/entry.S          |  87 -----------------------
> > arch/riscv/kernel/fpu.S            | 106 +++++++++++++++++++++++++++++
> > arch/riscv/kernel/process.c        |   6 +-
> > arch/riscv/kernel/signal.c         |  75 ++++++++++++--------
> > 9 files changed, 196 insertions(+), 127 deletions(-)
> > create mode 100644 arch/riscv/kernel/fpu.S
> 
> Thanks!  I'll add this to our for-next branch.

Any updates?



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