x86/fpu: Remove fpu->initialized usage in copy_fpstate_to_sigframe()
With lazy-FPU support the (now named variable) ->initialized was set to true if the CPU's FPU registers were holding a valid state of the FPU registers for the active process. If it was set to false then the FPU state was saved in fpu->state and the FPU was deactivated. With lazy-FPU gone, ->initialized is always true for user threads and kernel threads never call this function so ->initialized is always true in copy_fpstate_to_sigframe(). The using_compacted_format() check is also a leftover from the lazy-FPU time. In the ->initialized == false case copy_to_user() would copy the compacted buffer while userland would expect the non-compacted format instead. So in order to save the FPU state in the non-compacted form it issues XSAVE to save the *current* FPU state. If the FPU is not enabled, the attempt raises the FPU trap, the trap restores the FPU contents and re-enables the FPU and XSAVE is invoked again and succeeds. *This* does not longer work since commit bef8b6da ("x86/fpu: Handle #NM without FPU emulation as an error") Remove the check for ->initialized because it is always true and remove the false condition. Update the comment to reflect that the state is always live. [ bp: Massage. ] Signed-off-by:Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by:
Borislav Petkov <bp@suse.de> Reviewed-by:
Dave Hansen <dave.hansen@intel.com> Reviewed-by:
Thomas Gleixner <tglx@linutronix.de> Cc: Andy Lutomirski <luto@kernel.org> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jann Horn <jannh@google.com> Cc: "Jason A. Donenfeld" <Jason@zx2c4.com> Cc: kvm ML <kvm@vger.kernel.org> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Radim Krčmář <rkrcmar@redhat.com> Cc: Rik van Riel <riel@surriel.com> Cc: x86-ml <x86@kernel.org> Link: https://lkml.kernel.org/r/20190403164156.19645-6-bigeasy@linutronix.de
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