[Patch v4 03/18] x86/speculation: Reorganize cpu_show_common()

[Tim Chen <tim.c.chen@linux.intel.com>]

Extract the logic to show IBPB, STIBP usages in cpu_show_common()
into helper functions.

Later patches will add other userspace Spectre v2 mitigation modes.
This patch makes it easy to show IBPB and STIBP
usage scenario according to the mitigation mode.

Signed-off-by: Tim Chen <tim.c.chen@linux.intel.com>
---
 arch/x86/kernel/cpu/bugs.c | 19 +++++++++++++++++--
 1 file changed, 17 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c
index 6021b17..af456f4 100644
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -851,6 +851,22 @@ static ssize_t l1tf_show_state(char *buf)
 }
 #endif
 
+static char *stibp_state(void)
+{
+	if (x86_spec_ctrl_base & SPEC_CTRL_STIBP)
+		return ", STIBP";
+	else
+		return "";
+}
+
+static char *ibpb_state(void)
+{
+	if (boot_cpu_has(X86_FEATURE_USE_IBPB))
+		return ", IBPB";
+	else
+		return "";
+}
+
 static ssize_t cpu_show_common(struct device *dev, struct device_attribute *attr,
 			       char *buf, unsigned int bug)
 {
@@ -872,9 +888,8 @@ static ssize_t cpu_show_common(struct device *dev, struct device_attribute *attr
 
 	case X86_BUG_SPECTRE_V2:
 		return sprintf(buf, "%s%s%s%s%s%s\n", spectre_v2_strings[spectre_v2_enabled],
-			       boot_cpu_has(X86_FEATURE_USE_IBPB) ? ", IBPB" : "",
 			       boot_cpu_has(X86_FEATURE_USE_IBRS_FW) ? ", IBRS_FW" : "",
-			       (x86_spec_ctrl_base & SPEC_CTRL_STIBP) ? ", STIBP" : "",
+			       ibpb_state(), stibp_state(),
 			       boot_cpu_has(X86_FEATURE_RSB_CTXSW) ? ", RSB filling" : "",
 			       spectre_v2_module_string());
 
-- 
2.9.4