Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
x86/cpu: Create helper function to parse the 'clearcpuid=' boot parameter
This is in preparation for a later commit that will reuse this code, to
make review convenient.
Factor out a helper function which does the full handling for this arg
including printing info to the console.
No functional change intended.
Signed-off-by: Brendan Jackman <jackmanb@google.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20241220-force-cpu-bug-v2-1-7dc71bce742a@google.com
authored by
Brendan Jackman
and committed by
Ingo Molnar
f034937f
a4248ee1
+52
-44
+52
-44
arch/x86/kernel/cpu/common.c
+52
-44
arch/x86/kernel/cpu/common.c
···
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#endif
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}
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/*
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* We parse cpu parameters early because fpu__init_system() is executed
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* before parse_early_param().
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*/
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static void __init cpu_parse_early_param(void)
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+
static inline void parse_clearcpuid(char *arg)
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{
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char arg[128];
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char *argptr = arg, *opt;
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int arglen, taint = 0;
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#ifdef CONFIG_X86_32
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if (cmdline_find_option_bool(boot_command_line, "no387"))
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#ifdef CONFIG_MATH_EMULATION
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setup_clear_cpu_cap(X86_FEATURE_FPU);
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#else
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pr_err("Option 'no387' required CONFIG_MATH_EMULATION enabled.\n");
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#endif
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if (cmdline_find_option_bool(boot_command_line, "nofxsr"))
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setup_clear_cpu_cap(X86_FEATURE_FXSR);
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#endif
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if (cmdline_find_option_bool(boot_command_line, "noxsave"))
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setup_clear_cpu_cap(X86_FEATURE_XSAVE);
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if (cmdline_find_option_bool(boot_command_line, "noxsaveopt"))
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setup_clear_cpu_cap(X86_FEATURE_XSAVEOPT);
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if (cmdline_find_option_bool(boot_command_line, "noxsaves"))
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setup_clear_cpu_cap(X86_FEATURE_XSAVES);
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if (cmdline_find_option_bool(boot_command_line, "nousershstk"))
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setup_clear_cpu_cap(X86_FEATURE_USER_SHSTK);
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/* Minimize the gap between FRED is available and available but disabled. */
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arglen = cmdline_find_option(boot_command_line, "fred", arg, sizeof(arg));
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if (arglen != 2 || strncmp(arg, "on", 2))
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setup_clear_cpu_cap(X86_FEATURE_FRED);
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arglen = cmdline_find_option(boot_command_line, "clearcpuid", arg, sizeof(arg));
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if (arglen <= 0)
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return;
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char *opt;
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int taint = 0;
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pr_info("Clearing CPUID bits:");
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while (argptr) {
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while (arg) {
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bool found __maybe_unused = false;
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unsigned int bit;
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opt = strsep(&argptr, ",");
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opt = strsep(&arg, ",");
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/*
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* Handle naked numbers first for feature flags which don't
···
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if (!found)
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pr_cont(" (unknown: %s)", opt);
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}
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pr_cont("\n");
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if (taint)
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add_taint(TAINT_CPU_OUT_OF_SPEC, LOCKDEP_STILL_OK);
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pr_cont("\n");
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}
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+
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+
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/*
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* We parse cpu parameters early because fpu__init_system() is executed
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* before parse_early_param().
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+
*/
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static void __init cpu_parse_early_param(void)
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{
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char arg[128];
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int arglen;
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+
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#ifdef CONFIG_X86_32
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if (cmdline_find_option_bool(boot_command_line, "no387"))
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#ifdef CONFIG_MATH_EMULATION
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setup_clear_cpu_cap(X86_FEATURE_FPU);
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#else
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pr_err("Option 'no387' required CONFIG_MATH_EMULATION enabled.\n");
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#endif
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+
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if (cmdline_find_option_bool(boot_command_line, "nofxsr"))
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setup_clear_cpu_cap(X86_FEATURE_FXSR);
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#endif
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+
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if (cmdline_find_option_bool(boot_command_line, "noxsave"))
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setup_clear_cpu_cap(X86_FEATURE_XSAVE);
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+
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if (cmdline_find_option_bool(boot_command_line, "noxsaveopt"))
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setup_clear_cpu_cap(X86_FEATURE_XSAVEOPT);
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+
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if (cmdline_find_option_bool(boot_command_line, "noxsaves"))
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setup_clear_cpu_cap(X86_FEATURE_XSAVES);
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+
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if (cmdline_find_option_bool(boot_command_line, "nousershstk"))
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setup_clear_cpu_cap(X86_FEATURE_USER_SHSTK);
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+
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/* Minimize the gap between FRED is available and available but disabled. */
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arglen = cmdline_find_option(boot_command_line, "fred", arg, sizeof(arg));
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if (arglen != 2 || strncmp(arg, "on", 2))
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setup_clear_cpu_cap(X86_FEATURE_FRED);
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+
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arglen = cmdline_find_option(boot_command_line, "clearcpuid", arg, sizeof(arg));
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if (arglen <= 0)
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return;
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parse_clearcpuid(arg);
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}
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/*