Re: [PATCH v17 04/26] x86/cpufeatures: Introduce X86_FEATURE_CET and setup functions
From: Borislav Petkov <bp@alien8.de>
Date: 2021-01-11 17:57:41
Also in:
linux-arch, linux-doc, linux-mm, lkml
On Tue, Dec 29, 2020 at 01:30:31PM -0800, Yu-cheng Yu wrote:
quoted hunk ↗ jump to hunk
@@ -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);
+#endifThere's no need for this function...
quoted hunk ↗ jump to hunk
+} + /* * 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.
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