The following commit has been merged into the x86/cpu branch of tip:
Commit-ID: f034937f5af32188cd1c07865c885b2f171e17bf
Gitweb: https://git.kernel.org/tip/f034937f5af32188cd1c07865c885b2f171e17bf
Author: Brendan Jackman <jackmanb@xxxxxxxxxx>
AuthorDate: Fri, 20 Dec 2024 15:18:31
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitterDate: Fri, 28 Feb 2025 10:57:49 +01:00
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@xxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20241220-force-cpu-bug-v2-1-7dc71bce742a@xxxxxxxxxx
---
arch/x86/kernel/cpu/common.c | 96 ++++++++++++++++++-----------------
1 file changed, 52 insertions(+), 44 deletions(-)
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 76598a9..137d3e0 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -1479,56 +1479,18 @@ static void detect_nopl(void)
#endif
}
-/*
- * We parse cpu parameters early because fpu__init_system() is executed
- * before parse_early_param().
- */
-static void __init cpu_parse_early_param(void)
+static inline void parse_clearcpuid(char *arg)
{
- char arg[128];
- char *argptr = arg, *opt;
- int arglen, taint = 0;
-
-#ifdef CONFIG_X86_32
- if (cmdline_find_option_bool(boot_command_line, "no387"))
-#ifdef CONFIG_MATH_EMULATION
- setup_clear_cpu_cap(X86_FEATURE_FPU);
-#else
- pr_err("Option 'no387' required CONFIG_MATH_EMULATION enabled.\n");
-#endif
-
- if (cmdline_find_option_bool(boot_command_line, "nofxsr"))
- setup_clear_cpu_cap(X86_FEATURE_FXSR);
-#endif
-
- if (cmdline_find_option_bool(boot_command_line, "noxsave"))
- setup_clear_cpu_cap(X86_FEATURE_XSAVE);
-
- 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);
-
- if (cmdline_find_option_bool(boot_command_line, "nousershstk"))
- setup_clear_cpu_cap(X86_FEATURE_USER_SHSTK);
-
- /* Minimize the gap between FRED is available and available but disabled. */
- arglen = cmdline_find_option(boot_command_line, "fred", arg, sizeof(arg));
- if (arglen != 2 || strncmp(arg, "on", 2))
- setup_clear_cpu_cap(X86_FEATURE_FRED);
-
- arglen = cmdline_find_option(boot_command_line, "clearcpuid", arg, sizeof(arg));
- if (arglen <= 0)
- return;
+ char *opt;
+ int taint = 0;
pr_info("Clearing CPUID bits:");
- while (argptr) {
+ while (arg) {
bool found __maybe_unused = false;
unsigned int bit;
- opt = strsep(&argptr, ",");
+ opt = strsep(&arg, ",");
/*
* Handle naked numbers first for feature flags which don't
@@ -1570,10 +1532,56 @@ static void __init cpu_parse_early_param(void)
if (!found)
pr_cont(" (unknown: %s)", opt);
}
- pr_cont("\n");
if (taint)
add_taint(TAINT_CPU_OUT_OF_SPEC, LOCKDEP_STILL_OK);
+
+ pr_cont("\n");
+}
+
+
+/*
+ * We parse cpu parameters early because fpu__init_system() is executed
+ * before parse_early_param().
+ */
+static void __init cpu_parse_early_param(void)
+{
+ char arg[128];
+ int arglen;
+
+#ifdef CONFIG_X86_32
+ if (cmdline_find_option_bool(boot_command_line, "no387"))
+#ifdef CONFIG_MATH_EMULATION
+ setup_clear_cpu_cap(X86_FEATURE_FPU);
+#else
+ pr_err("Option 'no387' required CONFIG_MATH_EMULATION enabled.\n");
+#endif
+
+ if (cmdline_find_option_bool(boot_command_line, "nofxsr"))
+ setup_clear_cpu_cap(X86_FEATURE_FXSR);
+#endif
+
+ if (cmdline_find_option_bool(boot_command_line, "noxsave"))
+ setup_clear_cpu_cap(X86_FEATURE_XSAVE);
+
+ 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);
+
+ if (cmdline_find_option_bool(boot_command_line, "nousershstk"))
+ setup_clear_cpu_cap(X86_FEATURE_USER_SHSTK);
+
+ /* Minimize the gap between FRED is available and available but disabled. */
+ arglen = cmdline_find_option(boot_command_line, "fred", arg, sizeof(arg));
+ if (arglen != 2 || strncmp(arg, "on", 2))
+ setup_clear_cpu_cap(X86_FEATURE_FRED);
+
+ arglen = cmdline_find_option(boot_command_line, "clearcpuid", arg, sizeof(arg));
+ if (arglen <= 0)
+ return;
+ parse_clearcpuid(arg);
}
/*
|