x86/cpu: Allow feature bit names from /proc/cpuinfo in clearcpuid=

[sfrench/cifs-2.6.git] / arch / x86 / kernel / cpu / common.c

diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index ed4417500700416768b6096a905e3e5d090b4d98..69c7ea84b00546088354688d1fe9325ddf23e40b 100644 (file)
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -1368,8 +1368,8 @@ static void detect_nopl(void)
 static void __init cpu_parse_early_param(void)
 {
        char arg[128];
-       char *argptr = arg;
-       int arglen, res, bit;
+       char *argptr = arg, *opt;
+       int arglen, taint = 0;
 
 #ifdef CONFIG_X86_32
        if (cmdline_find_option_bool(boot_command_line, "no387"))
@@ -1397,21 +1397,61 @@ static void __init cpu_parse_early_param(void)
                return;
 
        pr_info("Clearing CPUID bits:");
-       do {
-               res = get_option(&argptr, &bit);
-               if (res == 0 || res == 3)
-                       break;
 
-               /* If the argument was too long, the last bit may be cut off */
-               if (res == 1 && arglen >= sizeof(arg))
-                       break;
+       while (argptr) {
+               bool found __maybe_unused = false;
+               unsigned int bit;
+
+               opt = strsep(&argptr, ",");
+
+               /*
+                * Handle naked numbers first for feature flags which don't
+                * have names.
+                */
+               if (!kstrtouint(opt, 10, &bit)) {
+                       if (bit < NCAPINTS * 32) {
+
+#ifdef CONFIG_X86_FEATURE_NAMES
+                               /* empty-string, i.e., ""-defined feature flags */
+                               if (!x86_cap_flags[bit])
+                                       pr_cont(" " X86_CAP_FMT_NUM, x86_cap_flag_num(bit));
+                               else
+#endif
+                                       pr_cont(" " X86_CAP_FMT, x86_cap_flag(bit));
+
+                               setup_clear_cpu_cap(bit);
+                               taint++;
+                       }
+                       /*
+                        * The assumption is that there are no feature names with only
+                        * numbers in the name thus go to the next argument.
+                        */
+                       continue;
+               }
+
+#ifdef CONFIG_X86_FEATURE_NAMES
+               for (bit = 0; bit < 32 * NCAPINTS; bit++) {
+                       if (!x86_cap_flag(bit))
+                               continue;
 
-               if (bit >= 0 && bit < NCAPINTS * 32) {
-                       pr_cont(" " X86_CAP_FMT, x86_cap_flag(bit));
+                       if (strcmp(x86_cap_flag(bit), opt))
+                               continue;
+
+                       pr_cont(" %s", opt);
                        setup_clear_cpu_cap(bit);
+                       taint++;
+                       found = true;
+                       break;
                }
-       } while (res == 2);
+
+               if (!found)
+                       pr_cont(" (unknown: %s)", opt);
+#endif
+       }
        pr_cont("\n");
+
+       if (taint)
+               add_taint(TAINT_CPU_OUT_OF_SPEC, LOCKDEP_STILL_OK);
 }
 
 /*