Re: [PATCH] move i386's enabling of fxsr and xmmxcpt

From: Zwane Mwaikambo
Date: Thu Sep 08 2005 - 12:52:11 EST


On Thu, 8 Sep 2005, Jan Beulich wrote:

> (Note: Patch also attached because the inline version is certain to get
> line wrapped.)
>
> Move some code unrelated to any dealing with hardware bugs from i386's
> bugs.h to a more logical place.
>
> Signed-off-by: Jan Beulich <jbeulich@xxxxxxxxxx>
>
> diff -Npru 2.6.13/arch/i386/kernel/traps.c
> 2.6.13-i386-fxsr/arch/i386/kernel/traps.c
> --- 2.6.13/arch/i386/kernel/traps.c 2005-08-29 01:41:01.000000000
> +0200
> +++ 2.6.13-i386-fxsr/arch/i386/kernel/traps.c 2005-09-07
> 11:46:35.000000000 +0200
> @@ -1098,6 +1098,24 @@ void __init trap_init(void)
> #endif
> set_trap_gate(19,&simd_coprocessor_error);
>
> + if (cpu_has_fxsr) {
> + /*
> + * Verify that the FXSAVE/FXRSTOR data will be 16-byte
> aligned.
> + */
> + struct fxsrAlignAssert {
> + int _:!(offsetof(struct task_struct,
> thread.i387.fxsave) & 15);
> + };
> +
> + printk(KERN_INFO "Enabling fast FPU save and restore...
> ");
> + set_in_cr4(X86_CR4_OSFXSR);
> + printk("done.\n");
> + }
> + if (cpu_has_xmm) {
> + printk(KERN_INFO "Enabling unmasked SIMD FPU exception
> support... ");
> + set_in_cr4(X86_CR4_OSXMMEXCPT);
> + printk("done.\n");
> + }
> +
> set_system_gate(SYSCALL_VECTOR,&system_call);

Hmm doesn't this really belong in identify_cpu()?
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