s390/ctlreg: move control register code to separate file

Control register handling has nothing to do with low level SMP code.
Move it to a separate file.

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

arch/s390/boot/vmem.c

@@ -2,6 +2,7 @@
 #include <linux/sched/task.h>
 #include <linux/pgtable.h>
 #include <linux/kasan.h>
+#include <asm/ctl_reg.h>
 #include <asm/pgalloc.h>
 #include <asm/facility.h>
 #include <asm/sections.h>

arch/s390/include/asm/ctl_reg.h

@@ -74,16 +74,18 @@ static __always_inline void __ctl_clear_bit(unsigned int cr, unsigned int bit)
 	__ctl_load(reg, cr, cr);
 }
 
-void smp_ctl_set_clear_bit(int cr, int bit, bool set);
+void ctlreg_lock(void);
+void ctlreg_unlock(void);
+void ctl_set_clear_bit(int cr, int bit, bool set);
 
 static inline void ctl_set_bit(int cr, int bit)
 {
-	smp_ctl_set_clear_bit(cr, bit, true);
+	ctl_set_clear_bit(cr, bit, true);
 }
 
 static inline void ctl_clear_bit(int cr, int bit)
 {
-	smp_ctl_set_clear_bit(cr, bit, false);
+	ctl_set_clear_bit(cr, bit, false);
 }
 
 union ctlreg0 {

arch/s390/include/asm/fpu/internal.h

@@ -10,7 +10,6 @@
 #define _ASM_S390_FPU_INTERNAL_H
 
 #include <linux/string.h>
-#include <asm/ctl_reg.h>
 #include <asm/fpu/types.h>
 
 static inline void save_vx_regs(__vector128 *vxrs)

arch/s390/include/asm/uaccess.h

@@ -15,7 +15,6 @@
  */
 #include <asm/asm-extable.h>
 #include <asm/processor.h>
-#include <asm/ctl_reg.h>
 #include <asm/extable.h>
 #include <asm/facility.h>
 #include <asm-generic/access_ok.h>

arch/s390/kernel/Makefile

@@ -37,7 +37,7 @@ CFLAGS_unwind_bc.o	+= -fno-optimize-sibling-calls
 obj-y	:= head64.o traps.o time.o process.o earlypgm.o early.o setup.o idle.o vtime.o
 obj-y	+= processor.o syscall.o ptrace.o signal.o cpcmd.o ebcdic.o nmi.o
 obj-y	+= debug.o irq.o ipl.o dis.o diag.o vdso.o cpufeature.o
-obj-y	+= sysinfo.o lgr.o os_info.o
+obj-y	+= sysinfo.o lgr.o os_info.o ctlreg.o
 obj-y	+= runtime_instr.o cache.o fpu.o dumpstack.o guarded_storage.o sthyi.o
 obj-y	+= entry.o reipl.o kdebugfs.o alternative.o
 obj-y	+= nospec-branch.o ipl_vmparm.o machine_kexec_reloc.o unwind_bc.o

arch/s390/kernel/ctlreg.c

@@ -0,0 +1,62 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *	Copyright IBM Corp. 1999, 2023
+ */
+
+#include <linux/spinlock.h>
+#include <linux/smp.h>
+#include <asm/abs_lowcore.h>
+#include <asm/ctl_reg.h>
+
+/*
+ * ctl_lock guards access to global control register contents which
+ * are kept in the control register save area within absolute lowcore
+ * at physical address zero.
+ */
+static DEFINE_SPINLOCK(ctl_lock);
+
+void ctlreg_lock(void)
+	__acquires(&ctl_lock)
+{
+	spin_lock(&ctl_lock);
+}
+
+void ctlreg_unlock(void)
+	__releases(&ctl_lock)
+{
+	spin_unlock(&ctl_lock);
+}
+
+struct ctl_bit_parms {
+	unsigned long orval;
+	unsigned long andval;
+	int cr;
+};
+
+static void ctl_bit_callback(void *info)
+{
+	struct ctl_bit_parms *pp = info;
+	unsigned long regs[16];
+
+	__ctl_store(regs, 0, 15);
+	regs[pp->cr] &= pp->andval;
+	regs[pp->cr] |= pp->orval;
+	__ctl_load(regs, 0, 15);
+}
+
+void ctl_set_clear_bit(int cr, int bit, bool set)
+{
+	struct ctl_bit_parms pp = { .cr = cr, };
+	struct lowcore *abs_lc;
+
+	pp.orval  = set ? 1UL << bit : 0;
+	pp.andval = set ? -1UL : ~(1UL << bit);
+	ctlreg_lock();
+	abs_lc = get_abs_lowcore();
+	abs_lc->cregs_save_area[cr] &= pp.andval;
+	abs_lc->cregs_save_area[cr] |= pp.orval;
+	put_abs_lowcore(abs_lc);
+	on_each_cpu(ctl_bit_callback, &pp, 1);
+	ctlreg_unlock();
+}
+EXPORT_SYMBOL(ctl_set_clear_bit);

arch/s390/kernel/smp.c

@@ -37,6 +37,7 @@
 #include <linux/crash_dump.h>
 #include <linux/kprobes.h>
 #include <asm/asm-offsets.h>
+#include <asm/ctl_reg.h>
 #include <asm/pfault.h>
 #include <asm/diag.h>
 #include <asm/switch_to.h>
@@ -567,54 +568,6 @@ void arch_irq_work_raise(void)
 }
 #endif
 
-/*
- * parameter area for the set/clear control bit callbacks
- */
-struct ec_creg_mask_parms {
-	unsigned long orval;
-	unsigned long andval;
-	int cr;
-};
-
-/*
- * callback for setting/clearing control bits
- */
-static void smp_ctl_bit_callback(void *info)
-{
-	struct ec_creg_mask_parms *pp = info;
-	unsigned long cregs[16];
-
-	__ctl_store(cregs, 0, 15);
-	cregs[pp->cr] = (cregs[pp->cr] & pp->andval) | pp->orval;
-	__ctl_load(cregs, 0, 15);
-}
-
-static DEFINE_SPINLOCK(ctl_lock);
-
-void smp_ctl_set_clear_bit(int cr, int bit, bool set)
-{
-	struct ec_creg_mask_parms parms = { .cr = cr, };
-	struct lowcore *abs_lc;
-	u64 ctlreg;
-
-	if (set) {
-		parms.orval = 1UL << bit;
-		parms.andval = -1UL;
-	} else {
-		parms.orval = 0;
-		parms.andval = ~(1UL << bit);
-	}
-	spin_lock(&ctl_lock);
-	abs_lc = get_abs_lowcore();
-	ctlreg = abs_lc->cregs_save_area[cr];
-	ctlreg = (ctlreg & parms.andval) | parms.orval;
-	abs_lc->cregs_save_area[cr] = ctlreg;
-	put_abs_lowcore(abs_lc);
-	on_each_cpu(smp_ctl_bit_callback, &parms, 1);
-	spin_unlock(&ctl_lock);
-}
-EXPORT_SYMBOL(smp_ctl_set_clear_bit);
-
 #ifdef CONFIG_CRASH_DUMP
 
 int smp_store_status(int cpu)
@@ -935,14 +888,14 @@ int __cpu_up(unsigned int cpu, struct task_struct *tidle)
 	 * Make sure global control register contents do not change
 	 * until new CPU has initialized control registers.
 	 */
-	spin_lock(&ctl_lock);
+	ctlreg_lock();
 	pcpu_prepare_secondary(pcpu, cpu);
 	pcpu_attach_task(pcpu, tidle);
 	pcpu_start_fn(pcpu, smp_start_secondary, NULL);
 	/* Wait until cpu puts itself in the online & active maps */
 	while (!cpu_online(cpu))
 		cpu_relax();
-	spin_unlock(&ctl_lock);
+	ctlreg_unlock();
 	return 0;
 }
 

arch/s390/lib/uaccess.c

@@ -12,6 +12,7 @@
 #include <linux/export.h>
 #include <linux/mm.h>
 #include <asm/asm-extable.h>
+#include <asm/ctl_reg.h>
 
 #ifdef CONFIG_DEBUG_ENTRY
 void debug_user_asce(int exit)

arch/s390/mm/vmem.c

@@ -14,6 +14,7 @@
 #include <linux/sort.h>
 #include <asm/cacheflush.h>
 #include <asm/nospec-branch.h>
+#include <asm/ctl_reg.h>
 #include <asm/pgalloc.h>
 #include <asm/setup.h>
 #include <asm/tlbflush.h>

drivers/s390/char/sclp_early_core.c

@@ -6,6 +6,7 @@
 
 #include <linux/kernel.h>
 #include <asm/processor.h>
+#include <asm/ctl_reg.h>
 #include <asm/lowcore.h>
 #include <asm/ebcdic.h>
 #include <asm/irq.h>