x86/fsgsbase: Replace static_cpu_has() with boot_cpu_has()

ptrace and prctl() are not really fast paths to warrant the use of
static_cpu_has() and cause alternatives patching for no good reason.
Replace with boot_cpu_has() which is simple and fast enough.

No functional changes.
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20200818103715.32736-1-bp@alien8.de

arch/x86/include/asm/fsgsbase.h

@@ -57,7 +57,7 @@ static inline unsigned long x86_fsbase_read_cpu(void)
 {
 	unsigned long fsbase;
 
-	if (static_cpu_has(X86_FEATURE_FSGSBASE))
+	if (boot_cpu_has(X86_FEATURE_FSGSBASE))
 		fsbase = rdfsbase();
 	else
 		rdmsrl(MSR_FS_BASE, fsbase);
@@ -67,7 +67,7 @@ static inline unsigned long x86_fsbase_read_cpu(void)
 
 static inline void x86_fsbase_write_cpu(unsigned long fsbase)
 {
-	if (static_cpu_has(X86_FEATURE_FSGSBASE))
+	if (boot_cpu_has(X86_FEATURE_FSGSBASE))
 		wrfsbase(fsbase);
 	else
 		wrmsrl(MSR_FS_BASE, fsbase);

arch/x86/kernel/process_64.c

@@ -407,7 +407,7 @@ unsigned long x86_gsbase_read_cpu_inactive(void)
 {
 	unsigned long gsbase;
 
-	if (static_cpu_has(X86_FEATURE_FSGSBASE)) {
+	if (boot_cpu_has(X86_FEATURE_FSGSBASE)) {
 		unsigned long flags;
 
 		local_irq_save(flags);
@@ -422,7 +422,7 @@ unsigned long x86_gsbase_read_cpu_inactive(void)
 
 void x86_gsbase_write_cpu_inactive(unsigned long gsbase)
 {
-	if (static_cpu_has(X86_FEATURE_FSGSBASE)) {
+	if (boot_cpu_has(X86_FEATURE_FSGSBASE)) {
 		unsigned long flags;
 
 		local_irq_save(flags);
@@ -439,7 +439,7 @@ unsigned long x86_fsbase_read_task(struct task_struct *task)
 
 	if (task == current)
 		fsbase = x86_fsbase_read_cpu();
-	else if (static_cpu_has(X86_FEATURE_FSGSBASE) ||
+	else if (boot_cpu_has(X86_FEATURE_FSGSBASE) ||
 		 (task->thread.fsindex == 0))
 		fsbase = task->thread.fsbase;
 	else
@@ -454,7 +454,7 @@ unsigned long x86_gsbase_read_task(struct task_struct *task)
 
 	if (task == current)
 		gsbase = x86_gsbase_read_cpu_inactive();
-	else if (static_cpu_has(X86_FEATURE_FSGSBASE) ||
+	else if (boot_cpu_has(X86_FEATURE_FSGSBASE) ||
 		 (task->thread.gsindex == 0))
 		gsbase = task->thread.gsbase;
 	else