x86/bugs: Remove default case for fully switched enums

For enum switch statements which handle all possible cases, remove the
default case so a compiler warning gets printed if one of the enums gets
accidentally omitted from the switch statement.

Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Acked-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/fcf6feefab991b72e411c2aed688b18e65e06aed.1693889988.git.jpoimboe@kernel.org

diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c
index 4f1ad2350f4989d344a7091441f3bcad613acfde..941ac94ad0d472f19e0cdbbb4ace76a476fc0a66 100644 (file)
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -1019,7 +1019,6 @@ static void __init retbleed_select_mitigation(void)
 
 do_cmd_auto:
        case RETBLEED_CMD_AUTO:
-       default:
                if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD ||
                    boot_cpu_data.x86_vendor == X86_VENDOR_HYGON) {
                        if (IS_ENABLED(CONFIG_CPU_UNRET_ENTRY))
@@ -1290,6 +1289,8 @@ spectre_v2_user_select_mitigation(void)
 
                spectre_v2_user_ibpb = mode;
                switch (cmd) {
+               case SPECTRE_V2_USER_CMD_NONE:
+                       break;
                case SPECTRE_V2_USER_CMD_FORCE:
                case SPECTRE_V2_USER_CMD_PRCTL_IBPB:
                case SPECTRE_V2_USER_CMD_SECCOMP_IBPB:
@@ -1301,8 +1302,6 @@ spectre_v2_user_select_mitigation(void)
                case SPECTRE_V2_USER_CMD_SECCOMP:
                        static_branch_enable(&switch_mm_cond_ibpb);
                        break;
-               default:
-                       break;
                }
 
                pr_info("mitigation: Enabling %s Indirect Branch Prediction Barrier\n",
@@ -2160,6 +2159,10 @@ static int l1d_flush_prctl_get(struct task_struct *task)
 static int ssb_prctl_get(struct task_struct *task)
 {
        switch (ssb_mode) {
+       case SPEC_STORE_BYPASS_NONE:
+               if (boot_cpu_has_bug(X86_BUG_SPEC_STORE_BYPASS))
+                       return PR_SPEC_ENABLE;
+               return PR_SPEC_NOT_AFFECTED;
        case SPEC_STORE_BYPASS_DISABLE:
                return PR_SPEC_DISABLE;
        case SPEC_STORE_BYPASS_SECCOMP:
@@ -2171,11 +2174,8 @@ static int ssb_prctl_get(struct task_struct *task)
                if (task_spec_ssb_disable(task))
                        return PR_SPEC_PRCTL | PR_SPEC_DISABLE;
                return PR_SPEC_PRCTL | PR_SPEC_ENABLE;
-       default:
-               if (boot_cpu_has_bug(X86_BUG_SPEC_STORE_BYPASS))
-                       return PR_SPEC_ENABLE;
-               return PR_SPEC_NOT_AFFECTED;
        }
+       BUG();
 }
 
 static int ib_prctl_get(struct task_struct *task)
@@ -2504,9 +2504,6 @@ static void __init srso_select_mitigation(void)
                        pr_err("WARNING: kernel not compiled with CPU_SRSO.\n");
                 }
                break;
-
-       default:
-               break;
        }
 
 out: