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Groups > linux.kernel > #1310460
| From | Yu-cheng Yu <yu-cheng.yu@intel.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [tip:x86/asm] x86/fpu: Fix early FPU command-line parsing |
| Date | 2016-01-15 22:00 +0100 |
| Message-ID | <qRjDs-2R7-15@gated-at.bofh.it> (permalink) |
| References | <qO4Ui-7jF-21@gated-at.bofh.it> <qQ5VV-FV-47@gated-at.bofh.it> <qRjaq-2FM-1@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On Fri, Jan 15, 2016 at 09:28:58PM +0100, Borislav Petkov wrote:
> > +static void __init fpu__init_parse_early_param(void)
> > +{
> > + /*
> > + * No need to check "eagerfpu=auto" again, since it is the
> > + * initial default.
> > + */
> > + if (cmdline_find_option_bool(boot_command_line, "eagerfpu=off"))
> > + eagerfpu = DISABLE;
> > + else if (cmdline_find_option_bool(boot_command_line, "eagerfpu=on"))
> > + eagerfpu = ENABLE;
> > +
> > + if (cmdline_find_option_bool(boot_command_line, "no387"))
> > + setup_clear_cpu_cap(X86_FEATURE_FPU);
> > +
> > + if (cmdline_find_option_bool(boot_command_line, "nofxsr")) {
> > + setup_clear_cpu_cap(X86_FEATURE_FXSR);
> > + setup_clear_cpu_cap(X86_FEATURE_FXSR_OPT);
> > + setup_clear_cpu_cap(X86_FEATURE_XMM);
> > + }
> > +
> > + if (cmdline_find_option_bool(boot_command_line, "noxsave"))
> > + fpu__xstate_clear_all_cpu_caps();
> > +
> > + if (cmdline_find_option_bool(boot_command_line, "noxsaveopt"))
> > + setup_clear_cpu_cap(X86_FEATURE_XSAVEOPT);
> > +
> > + if (cmdline_find_option_bool(boot_command_line, "noxsaves"))
> > + setup_clear_cpu_cap(X86_FEATURE_XSAVES);
>
> This could certainly be improved: we're iterating over the *whole*
> command line each time for each option unconditionally instead of
> iterating word by word and comparing it with all strings.
>
> We'd need something like cmdline_for_each_word() or so, though...
>
That is a good point. I will work on it.
Thanks,
Yu-cheng
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[PATCH 0/4] x86/fpu: FPU init code bugfixes yu-cheng yu <yu-cheng.yu@intel.com> - 2016-01-06 23:40 +0100
[PATCH 2/4] x86/fpu: Disable XGETBV1 when no XSAVE yu-cheng yu <yu-cheng.yu@intel.com> - 2016-01-06 23:40 +0100
[tip:x86/asm] x86/fpu: Disable XGETBV1 when no XSAVE tip-bot for yu-cheng yu <tipbot@zytor.com> - 2016-01-12 13:10 +0100
[PATCH 3/4] x86/fpu: Disable MPX when eagerfpu is off yu-cheng yu <yu-cheng.yu@intel.com> - 2016-01-06 23:40 +0100
[tip:x86/asm] x86/fpu: Disable MPX when eagerfpu is off tip-bot for yu-cheng yu <tipbot@zytor.com> - 2016-01-12 13:10 +0100
[PATCH 4/4] x86/fpu: Disable AVX when eagerfpu is off yu-cheng yu <yu-cheng.yu@intel.com> - 2016-01-06 23:40 +0100
[tip:x86/asm] x86/fpu: Disable AVX when eagerfpu is off tip-bot for yu-cheng yu <tipbot@zytor.com> - 2016-01-12 13:10 +0100
[PATCH 1/4] x86/fpu: Fix early fpu command-line parsing yu-cheng yu <yu-cheng.yu@intel.com> - 2016-01-06 23:40 +0100
[tip:x86/asm] x86/fpu: Fix early FPU command-line parsing tip-bot for yu-cheng yu <tipbot@zytor.com> - 2016-01-12 13:10 +0100
Re: [tip:x86/asm] x86/fpu: Fix early FPU command-line parsing Borislav Petkov <bp@alien8.de> - 2016-01-15 21:30 +0100
Re: [tip:x86/asm] x86/fpu: Fix early FPU command-line parsing Yu-cheng Yu <yu-cheng.yu@intel.com> - 2016-01-15 22:00 +0100
Re: [tip:x86/asm] x86/fpu: Fix early FPU command-line parsing Borislav Petkov <bp@alien8.de> - 2016-01-15 22:10 +0100
Re: [tip:x86/asm] x86/fpu: Fix early FPU command-line parsing Dave Hansen <dave.hansen@linux.intel.com> - 2016-01-15 22:10 +0100
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