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Diffstat (limited to 'arch/x86/kernel/cpu/common.c')
-rw-r--r--arch/x86/kernel/cpu/common.c55
1 files changed, 55 insertions, 0 deletions
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index c5d6f17d9b9d..3c7519398ad5 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -23,6 +23,7 @@
#include <linux/syscore_ops.h>
#include <linux/pgtable.h>
+#include <asm/cmdline.h>
#include <asm/stackprotector.h>
#include <asm/perf_event.h>
#include <asm/mmu_context.h>
@@ -1221,6 +1222,59 @@ static void detect_nopl(void)
}
/*
+ * 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];
+ char *argptr = arg;
+ int arglen, res, bit;
+
+#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);
+
+ arglen = cmdline_find_option(boot_command_line, "clearcpuid", arg, sizeof(arg));
+ if (arglen <= 0)
+ 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;
+
+ if (bit >= 0 && bit < NCAPINTS * 32) {
+ pr_cont(" " X86_CAP_FMT, x86_cap_flag(bit));
+ setup_clear_cpu_cap(bit);
+ }
+ } while (res == 2);
+ pr_cont("\n");
+}
+
+/*
* Do minimum CPU detection early.
* Fields really needed: vendor, cpuid_level, family, model, mask,
* cache alignment.
@@ -1255,6 +1309,7 @@ static void __init early_identify_cpu(struct cpuinfo_x86 *c)
get_cpu_cap(c);
get_cpu_address_sizes(c);
setup_force_cpu_cap(X86_FEATURE_CPUID);
+ cpu_parse_early_param();
if (this_cpu->c_early_init)
this_cpu->c_early_init(c);