diff options
| author | Vineet Gupta <vgupta@synopsys.com> | 2017-04-20 15:36:51 -0700 |
|---|---|---|
| committer | Vineet Gupta <vgupta@synopsys.com> | 2017-04-20 15:37:49 -0700 |
| commit | 3d5e80125a6e5649c6bdad8d5780e39ea422c67d (patch) | |
| tree | 5db65bfac17a6dbbff36d055b0292e9addeb8d90 /arch/arc/Kconfig | |
| parent | 6492f09e864417d382e22b922ae30693a7ce2982 (diff) | |
ARCv2: entry: save Accumulator register pair (r58:59) if present
Accumulator is present in configs with FPU and/or DSP MPY (mpy > 6)
Instead of doing this in pt_regs (and thus every kernel entry/exit),
this could have been done in context switch (and for user task only) as
currently kernel doesn't clobber these registers for its own accord.
However we will soon start using 64-bit multiply instructions for kernel
which can clobber these. Also gcc folks also plan to start using these
as GPRs, hence better to always save/restore them
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Diffstat (limited to 'arch/arc/Kconfig')
| -rw-r--r-- | arch/arc/Kconfig | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/arch/arc/Kconfig b/arch/arc/Kconfig index c9f30f4763ab..5d7fb3e7cb97 100644 --- a/arch/arc/Kconfig +++ b/arch/arc/Kconfig @@ -406,6 +406,14 @@ config ARC_HAS_DIV_REM bool "Insn: div, divu, rem, remu" default y +config ARC_HAS_ACCL_REGS + bool "Reg Pair ACCL:ACCH (FPU and/or MPY > 6)" + default n + help + Depending on the configuration, CPU can contain accumulator reg-pair + (also referred to as r58:r59). These can also be used by gcc as GPR so + kernel needs to save/restore per process + endif # ISA_ARCV2 endmenu # "ARC CPU Configuration" |