Messages in this thread Patch in this message | | | From | "Chang S. Bae" <> | Subject | [PATCH v11 21/29] x86/fpu/amx: Initialize child's AMX state | Date | Fri, 1 Oct 2021 15:37:20 -0700 |
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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 v5: * Introduced a new define. (Andy Lutomirski)
Changes from v4: * Added as a new patch. This was missing on previous versions. --- arch/x86/include/asm/fpu/xstate.h | 3 +++ arch/x86/kernel/fpu/core.c | 3 +++ 2 files changed, 6 insertions(+)
diff --git a/arch/x86/include/asm/fpu/xstate.h b/arch/x86/include/asm/fpu/xstate.h index e3d431e04bbf..0e355dfe711b 100644 --- a/arch/x86/include/asm/fpu/xstate.h +++ b/arch/x86/include/asm/fpu/xstate.h @@ -85,6 +85,9 @@ XFEATURE_MASK_INDEPENDENT | \ XFEATURE_MASK_SUPERVISOR_UNSUPPORTED) +/* Volatile states that a child does not inherit. */ +#define XFEATURE_MASK_CLEARED_ON_CLONE XFEATURE_MASK_XTILE + #ifdef CONFIG_X86_64 #define REX_PREFIX "0x48, " #else diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c index b722360d2a85..fdac0f430af3 100644 --- a/arch/x86/kernel/fpu/core.c +++ b/arch/x86/kernel/fpu/core.c @@ -300,6 +300,9 @@ int fpu_clone(struct task_struct *dst) save_fpregs_to_fpstate(dst_fpu); fpregs_unlock(); + if (xfeatures_mask_all & XFEATURE_MASK_CLEARED_ON_CLONE) + dst_fpu->state->xsave.header.xfeatures &= ~XFEATURE_MASK_CLEARED_ON_CLONE; + set_tsk_thread_flag(dst, TIF_NEED_FPU_LOAD); trace_x86_fpu_copy_src(src_fpu); -- 2.17.1
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