x86/mm/pkeys: Actually enable Memory Protection Keys in the CPU

[cascardo/linux.git] / arch / x86 / kernel / cpu / common.c

diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 37830de..4fac263 100644 (file)
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -162,6 +162,22 @@ static int __init x86_mpx_setup(char *s)
 }
 __setup("nompx", x86_mpx_setup);
 
+static int __init x86_noinvpcid_setup(char *s)
+{
+       /* noinvpcid doesn't accept parameters */
+       if (s)
+               return -EINVAL;
+
+       /* do not emit a message if the feature is not present */
+       if (!boot_cpu_has(X86_FEATURE_INVPCID))
+               return 0;
+
+       setup_clear_cpu_cap(X86_FEATURE_INVPCID);
+       pr_info("noinvpcid: INVPCID feature disabled\n");
+       return 0;
+}
+early_param("noinvpcid", x86_noinvpcid_setup);
+
 #ifdef CONFIG_X86_32
 static int cachesize_override = -1;
 static int disable_x86_serial_nr = 1;
@@ -287,6 +303,48 @@ static __always_inline void setup_smap(struct cpuinfo_x86 *c)
        }
 }
 
+/*
+ * Protection Keys are not available in 32-bit mode.
+ */
+static bool pku_disabled;
+
+static __always_inline void setup_pku(struct cpuinfo_x86 *c)
+{
+       if (!cpu_has(c, X86_FEATURE_PKU))
+               return;
+       if (pku_disabled)
+               return;
+
+       cr4_set_bits(X86_CR4_PKE);
+       /*
+        * Seting X86_CR4_PKE will cause the X86_FEATURE_OSPKE
+        * cpuid bit to be set.  We need to ensure that we
+        * update that bit in this CPU's "cpu_info".
+        */
+       get_cpu_cap(c);
+}
+
+#ifdef CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS
+static __init int setup_disable_pku(char *arg)
+{
+       /*
+        * Do not clear the X86_FEATURE_PKU bit.  All of the
+        * runtime checks are against OSPKE so clearing the
+        * bit does nothing.
+        *
+        * This way, we will see "pku" in cpuinfo, but not
+        * "ospke", which is exactly what we want.  It shows
+        * that the CPU has PKU, but the OS has not enabled it.
+        * This happens to be exactly how a system would look
+        * if we disabled the config option.
+        */
+       pr_info("x86: 'nopku' specified, disabling Memory Protection Keys\n");
+       pku_disabled = true;
+       return 1;
+}
+__setup("nopku", setup_disable_pku);
+#endif /* CONFIG_X86_64 */
+
 /*
  * Some CPU features depend on higher CPUID levels, which may not always
  * be available due to CPUID level capping or broken virtualization
@@ -611,6 +669,7 @@ void get_cpu_cap(struct cpuinfo_x86 *c)
                c->x86_capability[CPUID_7_0_EBX] = ebx;
 
                c->x86_capability[CPUID_6_EAX] = cpuid_eax(0x00000006);
+               c->x86_capability[CPUID_7_ECX] = ecx;
        }
 
        /* Extended state features: level 0x0000000d */
@@ -943,6 +1002,7 @@ static void identify_cpu(struct cpuinfo_x86 *c)
        init_hypervisor(c);
        x86_init_rdrand(c);
        x86_init_cache_qos(c);
+       setup_pku(c);
 
        /*
         * Clear/Set all flags overriden by options, need do it
@@ -1475,20 +1535,6 @@ void cpu_init(void)
 }
 #endif
 
-#ifdef CONFIG_X86_DEBUG_STATIC_CPU_HAS
-void warn_pre_alternatives(void)
-{
-       WARN(1, "You're using static_cpu_has before alternatives have run!\n");
-}
-EXPORT_SYMBOL_GPL(warn_pre_alternatives);
-#endif
-
-inline bool __static_cpu_has_safe(u16 bit)
-{
-       return boot_cpu_has(bit);
-}
-EXPORT_SYMBOL_GPL(__static_cpu_has_safe);
-
 static void bsp_resume(void)
 {
        if (this_cpu->c_bsp_resume)