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Date: Sat, 17 Jul 2021 08:28:57 -0700 From: "Chang S. Bae" <chang.seok.bae@...el.com> To: bp@...e.de, luto@...nel.org, tglx@...utronix.de, mingo@...nel.org, x86@...nel.org Cc: len.brown@...el.com, dave.hansen@...el.com, thiago.macieira@...el.com, jing2.liu@...el.com, ravi.v.shankar@...el.com, linux-kernel@...r.kernel.org, chang.seok.bae@...el.com Subject: [PATCH v8 20/26] x86/fpu/amx: Initialize child's AMX state Assure that a forked child starts AMX registers in the INIT-state. Signed-off-by: Chang S. Bae <chang.seok.bae@...el.com> Reviewed-by: Len Brown <len.brown@...el.com> Cc: x86@...nel.org Cc: linux-kernel@...r.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 907f11f95330..80bf107d515c 100644 --- a/arch/x86/include/asm/fpu/xstate.h +++ b/arch/x86/include/asm/fpu/xstate.h @@ -80,6 +80,9 @@ 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 541628bfc8c0..387118127f93 100644 --- a/arch/x86/kernel/fpu/core.c +++ b/arch/x86/kernel/fpu/core.c @@ -299,6 +299,9 @@ 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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