x86/speculation: Reorder the spec_v2 code

commit 15d6b7aab0793b2de8a05d8a828777dd24db424e upstream

Reorder the code so it is better grouped. No functional change.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: David Woodhouse <dwmw@amazon.co.uk>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Casey Schaufler <casey.schaufler@intel.com>
Cc: Asit Mallick <asit.k.mallick@intel.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Jon Masters <jcm@redhat.com>
Cc: Waiman Long <longman9394@gmail.com>
Cc: Greg KH <gregkh@linuxfoundation.org>
Cc: Dave Stewart <david.c.stewart@intel.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20181125185004.707122879@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c
index ccd08d1..9fea8ff 100644 (file)
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -123,29 +123,6 @@ void __init check_bugs(void)
 #endif
 }
 
-/* The kernel command line selection */
-enum spectre_v2_mitigation_cmd {
-       SPECTRE_V2_CMD_NONE,
-       SPECTRE_V2_CMD_AUTO,
-       SPECTRE_V2_CMD_FORCE,
-       SPECTRE_V2_CMD_RETPOLINE,
-       SPECTRE_V2_CMD_RETPOLINE_GENERIC,
-       SPECTRE_V2_CMD_RETPOLINE_AMD,
-};
-
-static const char *spectre_v2_strings[] = {
-       [SPECTRE_V2_NONE]                       = "Vulnerable",
-       [SPECTRE_V2_RETPOLINE_GENERIC]          = "Mitigation: Full generic retpoline",
-       [SPECTRE_V2_RETPOLINE_AMD]              = "Mitigation: Full AMD retpoline",
-       [SPECTRE_V2_IBRS_ENHANCED]              = "Mitigation: Enhanced IBRS",
-};
-
-#undef pr_fmt
-#define pr_fmt(fmt)     "Spectre V2 : " fmt
-
-static enum spectre_v2_mitigation spectre_v2_enabled __ro_after_init =
-       SPECTRE_V2_NONE;
-
 void
 x86_virt_spec_ctrl(u64 guest_spec_ctrl, u64 guest_virt_spec_ctrl, bool setguest)
 {
@@ -215,6 +192,12 @@ static void x86_amd_ssb_disable(void)
                wrmsrl(MSR_AMD64_LS_CFG, msrval);
 }
 
+#undef pr_fmt
+#define pr_fmt(fmt)     "Spectre V2 : " fmt
+
+static enum spectre_v2_mitigation spectre_v2_enabled __ro_after_init =
+       SPECTRE_V2_NONE;
+
 #ifdef RETPOLINE
 static bool spectre_v2_bad_module;
 
@@ -236,18 +219,6 @@ static inline const char *spectre_v2_module_string(void)
 static inline const char *spectre_v2_module_string(void) { return ""; }
 #endif
 
-static void __init spec2_print_if_insecure(const char *reason)
-{
-       if (boot_cpu_has_bug(X86_BUG_SPECTRE_V2))
-               pr_info("%s selected on command line.\n", reason);
-}
-
-static void __init spec2_print_if_secure(const char *reason)
-{
-       if (!boot_cpu_has_bug(X86_BUG_SPECTRE_V2))
-               pr_info("%s selected on command line.\n", reason);
-}
-
 static inline bool match_option(const char *arg, int arglen, const char *opt)
 {
        int len = strlen(opt);
@@ -255,24 +226,53 @@ static inline bool match_option(const char *arg, int arglen, const char *opt)
        return len == arglen && !strncmp(arg, opt, len);
 }
 
+/* The kernel command line selection for spectre v2 */
+enum spectre_v2_mitigation_cmd {
+       SPECTRE_V2_CMD_NONE,
+       SPECTRE_V2_CMD_AUTO,
+       SPECTRE_V2_CMD_FORCE,
+       SPECTRE_V2_CMD_RETPOLINE,
+       SPECTRE_V2_CMD_RETPOLINE_GENERIC,
+       SPECTRE_V2_CMD_RETPOLINE_AMD,
+};
+
+static const char *spectre_v2_strings[] = {
+       [SPECTRE_V2_NONE]                       = "Vulnerable",
+       [SPECTRE_V2_RETPOLINE_GENERIC]          = "Mitigation: Full generic retpoline",
+       [SPECTRE_V2_RETPOLINE_AMD]              = "Mitigation: Full AMD retpoline",
+       [SPECTRE_V2_IBRS_ENHANCED]              = "Mitigation: Enhanced IBRS",
+};
+
 static const struct {
        const char *option;
        enum spectre_v2_mitigation_cmd cmd;
        bool secure;
 } mitigation_options[] = {
-       { "off",               SPECTRE_V2_CMD_NONE,              false },
-       { "on",                SPECTRE_V2_CMD_FORCE,             true },
-       { "retpoline",         SPECTRE_V2_CMD_RETPOLINE,         false },
-       { "retpoline,amd",     SPECTRE_V2_CMD_RETPOLINE_AMD,     false },
-       { "retpoline,generic", SPECTRE_V2_CMD_RETPOLINE_GENERIC, false },
-       { "auto",              SPECTRE_V2_CMD_AUTO,              false },
+       { "off",                SPECTRE_V2_CMD_NONE,              false },
+       { "on",                 SPECTRE_V2_CMD_FORCE,             true  },
+       { "retpoline",          SPECTRE_V2_CMD_RETPOLINE,         false },
+       { "retpoline,amd",      SPECTRE_V2_CMD_RETPOLINE_AMD,     false },
+       { "retpoline,generic",  SPECTRE_V2_CMD_RETPOLINE_GENERIC, false },
+       { "auto",               SPECTRE_V2_CMD_AUTO,              false },
 };
 
+static void __init spec2_print_if_insecure(const char *reason)
+{
+       if (boot_cpu_has_bug(X86_BUG_SPECTRE_V2))
+               pr_info("%s selected on command line.\n", reason);
+}
+
+static void __init spec2_print_if_secure(const char *reason)
+{
+       if (!boot_cpu_has_bug(X86_BUG_SPECTRE_V2))
+               pr_info("%s selected on command line.\n", reason);
+}
+
 static enum spectre_v2_mitigation_cmd __init spectre_v2_parse_cmdline(void)
 {
+       enum spectre_v2_mitigation_cmd cmd = SPECTRE_V2_CMD_AUTO;
        char arg[20];
        int ret, i;
-       enum spectre_v2_mitigation_cmd cmd = SPECTRE_V2_CMD_AUTO;
 
        if (cmdline_find_option_bool(boot_command_line, "nospectre_v2"))
                return SPECTRE_V2_CMD_NONE;
@@ -315,48 +315,6 @@ static enum spectre_v2_mitigation_cmd __init spectre_v2_parse_cmdline(void)
        return cmd;
 }
 
-static bool stibp_needed(void)
-{
-       if (spectre_v2_enabled == SPECTRE_V2_NONE)
-               return false;
-
-       /* Enhanced IBRS makes using STIBP unnecessary. */
-       if (spectre_v2_enabled == SPECTRE_V2_IBRS_ENHANCED)
-               return false;
-
-       if (!boot_cpu_has(X86_FEATURE_STIBP))
-               return false;
-
-       return true;
-}
-
-static void update_stibp_msr(void *info)
-{
-       wrmsrl(MSR_IA32_SPEC_CTRL, x86_spec_ctrl_base);
-}
-
-void arch_smt_update(void)
-{
-       u64 mask;
-
-       if (!stibp_needed())
-               return;
-
-       mutex_lock(&spec_ctrl_mutex);
-
-       mask = x86_spec_ctrl_base & ~SPEC_CTRL_STIBP;
-       if (sched_smt_active())
-               mask |= SPEC_CTRL_STIBP;
-
-       if (mask != x86_spec_ctrl_base) {
-               pr_info("Spectre v2 cross-process SMT mitigation: %s STIBP\n",
-                       mask & SPEC_CTRL_STIBP ? "Enabling" : "Disabling");
-               x86_spec_ctrl_base = mask;
-               on_each_cpu(update_stibp_msr, NULL, 1);
-       }
-       mutex_unlock(&spec_ctrl_mutex);
-}
-
 static void __init spectre_v2_select_mitigation(void)
 {
        enum spectre_v2_mitigation_cmd cmd = spectre_v2_parse_cmdline();
@@ -459,6 +417,48 @@ specv2_set_mode:
        arch_smt_update();
 }
 
+static bool stibp_needed(void)
+{
+       if (spectre_v2_enabled == SPECTRE_V2_NONE)
+               return false;
+
+       /* Enhanced IBRS makes using STIBP unnecessary. */
+       if (spectre_v2_enabled == SPECTRE_V2_IBRS_ENHANCED)
+               return false;
+
+       if (!boot_cpu_has(X86_FEATURE_STIBP))
+               return false;
+
+       return true;
+}
+
+static void update_stibp_msr(void *info)
+{
+       wrmsrl(MSR_IA32_SPEC_CTRL, x86_spec_ctrl_base);
+}
+
+void arch_smt_update(void)
+{
+       u64 mask;
+
+       if (!stibp_needed())
+               return;
+
+       mutex_lock(&spec_ctrl_mutex);
+
+       mask = x86_spec_ctrl_base & ~SPEC_CTRL_STIBP;
+       if (sched_smt_active())
+               mask |= SPEC_CTRL_STIBP;
+
+       if (mask != x86_spec_ctrl_base) {
+               pr_info("Spectre v2 cross-process SMT mitigation: %s STIBP\n",
+                       mask & SPEC_CTRL_STIBP ? "Enabling" : "Disabling");
+               x86_spec_ctrl_base = mask;
+               on_each_cpu(update_stibp_msr, NULL, 1);
+       }
+       mutex_unlock(&spec_ctrl_mutex);
+}
+
 #undef pr_fmt
 #define pr_fmt(fmt)    "Speculative Store Bypass: " fmt