Messages in this thread |  | | Subject | Re: [PATCH v5 21/28] x86/fpu/amx: Initialize child's AMX state | From | Andy Lutomirski <> | Date | Sun, 23 May 2021 20:09:13 -0700 |
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On 5/23/21 12:32 PM, Chang S. Bae wrote: > Assure that a forked child starts AMX registers in the INIT-state. > > Signed-off-by: Chang S. Bae <chang.seok.bae@intel.com> > Reviewed-by: Len Brown <len.brown@intel.com> > Cc: x86@kernel.org > Cc: linux-kernel@vger.kernel.org > --- > Changes from v4: > * Added as a new patch. This was missing on previous versions. > --- > arch/x86/kernel/fpu/core.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c > index 016c3adebec3..cccfeafe81e5 100644 > --- a/arch/x86/kernel/fpu/core.c > +++ b/arch/x86/kernel/fpu/core.c > @@ -285,6 +285,10 @@ int fpu__copy(struct task_struct *dst, struct task_struct *src) > > fpregs_unlock(); > > + /* AMX state is volatile, children do not inherit it. */ > + if (xfeatures_mask_all & XFEATURE_MASK_XTILE) > + dst_fpu->state->xsave.header.xfeatures &= ~(XFEATURE_MASK_XTILE); > + > set_tsk_thread_flag(dst, TIF_NEED_FPU_LOAD); > > trace_x86_fpu_copy_src(src_fpu); >
If we're going to start having different states with different behaviors, let's make them real defines.
#define XFEATURE_MASK_CLEARED_ON_CLONE ...
--Andy
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