s390/cpufeature: Convert MACHINE_HAS_GS to cpu_has_gs()

Convert MACHINE_HAS_... to cpu_has_...() which uses test_facility() instead
of testing the machine_flags lowcore member if the feature is present.

test_facility() generates better code since it results in a static branch
without accessing memory. The branch is patched via alternatives by the
decompressor depending on the availability of the required facility.

Reviewed-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

arch/s390/include/asm/cpufeature.h

@@ -22,6 +22,7 @@ enum {
 
 int cpu_have_feature(unsigned int nr);
 
+#define cpu_has_gs()		test_facility(133)
 #define cpu_has_rdp()		test_facility(194)
 #define cpu_has_seq_insn()	test_facility(85)
 

arch/s390/include/asm/setup.h

@@ -30,7 +30,6 @@
 #define MACHINE_FLAG_TLB_LC	BIT(12)
 #define MACHINE_FLAG_TLB_GUEST	BIT(14)
 #define MACHINE_FLAG_NX		BIT(15)
-#define MACHINE_FLAG_GS		BIT(16)
 #define MACHINE_FLAG_SCC	BIT(17)
 #define MACHINE_FLAG_PCI_MIO	BIT(18)
 
@@ -90,7 +89,6 @@ extern unsigned long mio_wb_bit_mask;
 #define MACHINE_HAS_TLB_LC	(get_lowcore()->machine_flags & MACHINE_FLAG_TLB_LC)
 #define MACHINE_HAS_TLB_GUEST	(get_lowcore()->machine_flags & MACHINE_FLAG_TLB_GUEST)
 #define MACHINE_HAS_NX		(get_lowcore()->machine_flags & MACHINE_FLAG_NX)
-#define MACHINE_HAS_GS		(get_lowcore()->machine_flags & MACHINE_FLAG_GS)
 #define MACHINE_HAS_SCC		(get_lowcore()->machine_flags & MACHINE_FLAG_SCC)
 #define MACHINE_HAS_PCI_MIO	(get_lowcore()->machine_flags & MACHINE_FLAG_PCI_MIO)
 

arch/s390/kernel/early.c

@@ -255,8 +255,6 @@ static __init void detect_machine_facilities(void)
 		system_ctl_set_bit(0, CR0_VECTOR_BIT);
 	if (test_facility(130))
 		get_lowcore()->machine_flags |= MACHINE_FLAG_NX;
-	if (test_facility(133))
-		get_lowcore()->machine_flags |= MACHINE_FLAG_GS;
 	if (test_facility(139) && (tod_clock_base.tod >> 63)) {
 		/* Enabled signed clock comparator comparisons */
 		get_lowcore()->machine_flags |= MACHINE_FLAG_SCC;

arch/s390/kernel/guarded_storage.c

@@ -4,6 +4,7 @@
  * Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
  */
 
+#include <linux/cpufeature.h>
 #include <linux/kernel.h>
 #include <linux/syscalls.h>
 #include <linux/signal.h>
@@ -109,7 +110,7 @@ static int gs_broadcast(void)
 SYSCALL_DEFINE2(s390_guarded_storage, int, command,
 		struct gs_cb __user *, gs_cb)
 {
-	if (!MACHINE_HAS_GS)
+	if (!cpu_has_gs())
 		return -EOPNOTSUPP;
 	switch (command) {
 	case GS_ENABLE:

arch/s390/kernel/machine_kexec.c

@@ -13,6 +13,7 @@
 #include <linux/reboot.h>
 #include <linux/ftrace.h>
 #include <linux/debug_locks.h>
+#include <linux/cpufeature.h>
 #include <asm/guarded_storage.h>
 #include <asm/pfault.h>
 #include <asm/cio.h>
@@ -94,7 +95,7 @@ static noinline void __machine_kdump(void *image)
 	mcesa = __va(get_lowcore()->mcesad & MCESA_ORIGIN_MASK);
 	if (cpu_has_vx())
 		save_vx_regs((__vector128 *) mcesa->vector_save_area);
-	if (MACHINE_HAS_GS) {
+	if (cpu_has_gs()) {
 		local_ctl_store(2, &cr2_old.reg);
 		cr2_new = cr2_old;
 		cr2_new.gse = 1;

arch/s390/kernel/nmi.c

@@ -9,6 +9,7 @@
  */
 
 #include <linux/kernel_stat.h>
+#include <linux/cpufeature.h>
 #include <linux/init.h>
 #include <linux/errno.h>
 #include <linux/entry-common.h>
@@ -45,7 +46,7 @@ static DEFINE_PER_CPU(struct mcck_struct, cpu_mcck);
 
 static inline int nmi_needs_mcesa(void)
 {
-	return cpu_has_vx() || MACHINE_HAS_GS;
+	return cpu_has_vx() || cpu_has_gs();
 }
 
 /*
@@ -61,7 +62,7 @@ void __init nmi_alloc_mcesa_early(u64 *mcesad)
 	if (!nmi_needs_mcesa())
 		return;
 	*mcesad = __pa(&boot_mcesa);
-	if (MACHINE_HAS_GS)
+	if (cpu_has_gs())
 		*mcesad |= ilog2(MCESA_MAX_SIZE);
 }
 
@@ -73,14 +74,14 @@ int nmi_alloc_mcesa(u64 *mcesad)
 	*mcesad = 0;
 	if (!nmi_needs_mcesa())
 		return 0;
-	size = MACHINE_HAS_GS ? MCESA_MAX_SIZE : MCESA_MIN_SIZE;
+	size = cpu_has_gs() ? MCESA_MAX_SIZE : MCESA_MIN_SIZE;
 	origin = kmalloc(size, GFP_KERNEL);
 	if (!origin)
 		return -ENOMEM;
 	/* The pointer is stored with mcesa_bits ORed in */
 	kmemleak_not_leak(origin);
 	*mcesad = __pa(origin);
-	if (MACHINE_HAS_GS)
+	if (cpu_has_gs())
 		*mcesad |= ilog2(MCESA_MAX_SIZE);
 	return 0;
 }

arch/s390/kernel/processor.c

@@ -8,6 +8,7 @@
 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
 
 #include <linux/stop_machine.h>
+#include <linux/cpufeature.h>
 #include <linux/bitops.h>
 #include <linux/kernel.h>
 #include <linux/random.h>
@@ -244,7 +245,7 @@ static int __init setup_hwcaps(void)
 		elf_hwcap |= HWCAP_NNPA;
 
 	/* guarded storage */
-	if (MACHINE_HAS_GS)
+	if (cpu_has_gs())
 		elf_hwcap |= HWCAP_GS;
 
 	if (MACHINE_HAS_PCI_MIO)

arch/s390/kernel/ptrace.c

@@ -11,6 +11,7 @@
 #include <linux/kernel.h>
 #include <linux/sched.h>
 #include <linux/sched/task_stack.h>
+#include <linux/cpufeature.h>
 #include <linux/mm.h>
 #include <linux/smp.h>
 #include <linux/errno.h>
@@ -75,7 +76,7 @@ void update_cr_regs(struct task_struct *task)
 		}
 	}
 	/* Take care of enable/disable of guarded storage. */
-	if (MACHINE_HAS_GS) {
+	if (cpu_has_gs()) {
 		cr2_new.gse = 0;
 		if (task->thread.gs_cb)
 			cr2_new.gse = 1;
@@ -1033,7 +1034,7 @@ static int s390_gs_cb_get(struct task_struct *target,
 {
 	struct gs_cb *data = target->thread.gs_cb;
 
-	if (!MACHINE_HAS_GS)
+	if (!cpu_has_gs())
 		return -ENODEV;
 	if (!data)
 		return -ENODATA;
@@ -1050,7 +1051,7 @@ static int s390_gs_cb_set(struct task_struct *target,
 	struct gs_cb gs_cb = { }, *data = NULL;
 	int rc;
 
-	if (!MACHINE_HAS_GS)
+	if (!cpu_has_gs())
 		return -ENODEV;
 	if (!target->thread.gs_cb) {
 		data = kzalloc(sizeof(*data), GFP_KERNEL);
@@ -1087,7 +1088,7 @@ static int s390_gs_bc_get(struct task_struct *target,
 {
 	struct gs_cb *data = target->thread.gs_bc_cb;
 
-	if (!MACHINE_HAS_GS)
+	if (!cpu_has_gs())
 		return -ENODEV;
 	if (!data)
 		return -ENODATA;
@@ -1101,7 +1102,7 @@ static int s390_gs_bc_set(struct task_struct *target,
 {
 	struct gs_cb *data = target->thread.gs_bc_cb;
 
-	if (!MACHINE_HAS_GS)
+	if (!cpu_has_gs())
 		return -ENODEV;
 	if (!data) {
 		data = kzalloc(sizeof(*data), GFP_KERNEL);

arch/s390/kernel/smp.c

@@ -18,6 +18,7 @@
 #define KMSG_COMPONENT "cpu"
 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
 
+#include <linux/cpufeature.h>
 #include <linux/workqueue.h>
 #include <linux/memblock.h>
 #include <linux/export.h>
@@ -561,10 +562,10 @@ int smp_store_status(int cpu)
 	if (__pcpu_sigp_relax(pcpu->address, SIGP_STORE_STATUS_AT_ADDRESS,
 			      pa) != SIGP_CC_ORDER_CODE_ACCEPTED)
 		return -EIO;
-	if (!cpu_has_vx() && !MACHINE_HAS_GS)
+	if (!cpu_has_vx() && !cpu_has_gs())
 		return 0;
 	pa = lc->mcesad & MCESA_ORIGIN_MASK;
-	if (MACHINE_HAS_GS)
+	if (cpu_has_gs())
 		pa |= lc->mcesad & MCESA_LC_MASK;
 	if (__pcpu_sigp_relax(pcpu->address, SIGP_STORE_ADDITIONAL_STATUS,
 			      pa) != SIGP_CC_ORDER_CODE_ACCEPTED)

arch/s390/kvm/interrupt.c

@@ -10,6 +10,7 @@
 #define KMSG_COMPONENT "kvm-s390"
 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
 
+#include <linux/cpufeature.h>
 #include <linux/interrupt.h>
 #include <linux/kvm_host.h>
 #include <linux/hrtimer.h>
@@ -577,7 +578,7 @@ static int __write_machine_check(struct kvm_vcpu *vcpu,
 	/* take care of lazy register loading */
 	kvm_s390_fpu_store(vcpu->run);
 	save_access_regs(vcpu->run->s.regs.acrs);
-	if (MACHINE_HAS_GS && vcpu->arch.gs_enabled)
+	if (cpu_has_gs() && vcpu->arch.gs_enabled)
 		save_gs_cb(current->thread.gs_cb);
 
 	/* Extended save area */

arch/s390/kvm/kvm-s390.c

@@ -23,6 +23,7 @@
 #include <linux/mman.h>
 #include <linux/module.h>
 #include <linux/moduleparam.h>
+#include <linux/cpufeature.h>
 #include <linux/random.h>
 #include <linux/slab.h>
 #include <linux/timer.h>
@@ -5171,7 +5172,7 @@ static void sync_regs_fmt2(struct kvm_vcpu *vcpu)
 		vcpu->arch.sie_block->fpf &= ~FPF_BPBC;
 		vcpu->arch.sie_block->fpf |= kvm_run->s.regs.bpbc ? FPF_BPBC : 0;
 	}
-	if (MACHINE_HAS_GS) {
+	if (cpu_has_gs()) {
 		preempt_disable();
 		local_ctl_set_bit(2, CR2_GUARDED_STORAGE_BIT);
 		if (current->thread.gs_cb) {
@@ -5237,7 +5238,7 @@ static void store_regs_fmt2(struct kvm_vcpu *vcpu)
 	kvm_run->s.regs.gbea = vcpu->arch.sie_block->gbea;
 	kvm_run->s.regs.bpbc = (vcpu->arch.sie_block->fpf & FPF_BPBC) == FPF_BPBC;
 	kvm_run->s.regs.diag318 = vcpu->arch.diag318_info.val;
-	if (MACHINE_HAS_GS) {
+	if (cpu_has_gs()) {
 		preempt_disable();
 		local_ctl_set_bit(2, CR2_GUARDED_STORAGE_BIT);
 		if (vcpu->arch.gs_enabled)