On Tue, Dec 29, 2020 at 01:30:31PM -0800, Yu-cheng Yu wrote:
> @@ -895,6 +903,12 @@ static void init_speculation_control(struct cpuinfo_x86 *c)
> }
> }
>
> +static void init_cet_features(struct cpuinfo_x86 *c)
> +{
> + if (cpu_has(c, X86_FEATURE_SHSTK) || cpu_has(c, X86_FEATURE_IBT))
> + set_cpu_cap(c, X86_FEATURE_CET);
> +}
No need for that function - just add this two-liner to bsp_init_intel()
and not in get_cpu_cap().
> +static void adjust_combined_cpu_features(void)
> +{
> +#ifdef CONFIG_X86_CET_USER
> + if (test_bit(X86_FEATURE_SHSTK, (unsigned long *)cpu_caps_cleared) &&
> + test_bit(X86_FEATURE_IBT, (unsigned long *)cpu_caps_cleared))
> + setup_clear_cpu_cap(X86_FEATURE_CET);
> +#endif
There's no need for this function...
> +}
> +
> /*
> * We parse cpu parameters early because fpu__init_system() is executed
> * before parse_early_param().
> @@ -1252,9 +1276,19 @@ static void __init cpu_parse_early_param(void)
> if (cmdline_find_option_bool(boot_command_line, "noxsaves"))
> setup_clear_cpu_cap(X86_FEATURE_XSAVES);
>
> + /*
> + * CET states are XSAVES states and options must be parsed early.
> + */
> +#ifdef CONFIG_X86_CET_USER
> + if (cmdline_find_option_bool(boot_command_line, "no_user_shstk"))
> + setup_clear_cpu_cap(X86_FEATURE_SHSTK);
... when you can do
setup_clear_cpu_cap(X86_FEATURE_CET);
here and...
> + if (cmdline_find_option_bool(boot_command_line, "no_user_ibt"))
> + setup_clear_cpu_cap(X86_FEATURE_IBT);
... here.
Thx.
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette
