On Fri, Jan 16, 2015 at 10:49:46AM +0000, Markos Chandras wrote:
> A prctl() call to set FR=0 for MIPS R6 should not be allowed
> since FR=1 is the only option for R6 cores.
>
> Cc: Paul Burton <paul.burton@xxxxxxxxxx>
> Cc: Matthew Fortune <matthew.fortune@xxxxxxxxxx>
> Signed-off-by: Markos Chandras <markos.chandras@xxxxxxxxxx>
> ---
> arch/mips/include/asm/fpu.h | 3 ++-
> arch/mips/kernel/process.c | 4 ++++
> 2 files changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/arch/mips/include/asm/fpu.h b/arch/mips/include/asm/fpu.h
> index 994d21939676..b96d9d327626 100644
> --- a/arch/mips/include/asm/fpu.h
> +++ b/arch/mips/include/asm/fpu.h
> @@ -68,7 +68,8 @@ static inline int __enable_fpu(enum fpu_mode mode)
> goto fr_common;
>
> case FPU_64BIT:
> -#if !(defined(CONFIG_CPU_MIPS32_R2) || defined(CONFIG_64BIT))
> +#if !(defined(CONFIG_CPU_MIPS32_R2) || defined(CONFIG_CPU_MIPS32_R6) \
> + || defined(CONFIG_64BIT))
Hi Markos,
This change really seems like a separate one, since it has nothing to do
with the prctl or disallowing FR=1, but rather with allowing FR=1 on r6.
Thanks,
Paul
> /* we only have a 32-bit FPU */
> return SIGFPE;
> #endif
> diff --git a/arch/mips/kernel/process.c b/arch/mips/kernel/process.c
> index b732c0ce2e56..41ebd5d0ac30 100644
> --- a/arch/mips/kernel/process.c
> +++ b/arch/mips/kernel/process.c
> @@ -581,6 +581,10 @@ int mips_set_process_fp_mode(struct task_struct *task, unsigned int value)
> if ((value & PR_FP_MODE_FRE) && !cpu_has_fre)
> return -EOPNOTSUPP;
>
> + /* FR = 0 not supported in MIPS R6 */
> + if (!(value & PR_FP_MODE_FR) && cpu_has_fpu && cpu_has_mips_r6)
> + return -EOPNOTSUPP;
> +
> /* Save FP & vector context, then disable FPU & MSA */
> if (task->signal == current->signal)
> lose_fpu(1);
> --
> 2.2.1
>
