s390: Move CIF flags to struct pcpu

To allow testing flags for offline CPUs, move the CIF flags
to struct pcpu. To avoid having to calculate the array index
for each access, add a pointer to the pcpu member for the current
cpu to lowcore.
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

arch/s390/include/asm/lowcore.h

@@ -97,8 +97,7 @@ struct lowcore {
 	__u64	save_area_async[8];		/* 0x0240 */
 	__u64	save_area_restart[1];		/* 0x0280 */
 
-	/* CPU flags. */
-	__u64	cpu_flags;			/* 0x0288 */
+	__u64	pcpu;				/* 0x0288 */
 
 	/* Return psws. */
 	psw_t	return_psw;			/* 0x0290 */

arch/s390/include/asm/processor.h

@@ -42,21 +42,37 @@
 #include <asm/irqflags.h>
 #include <asm/alternative.h>
 
+struct pcpu {
+	unsigned long ec_mask;		/* bit mask for ec_xxx functions */
+	unsigned long ec_clk;		/* sigp timestamp for ec_xxx */
+	unsigned long flags;		/* per CPU flags */
+	signed char state;		/* physical cpu state */
+	signed char polarization;	/* physical polarization */
+	u16 address;			/* physical cpu address */
+};
+
+DECLARE_PER_CPU(struct pcpu, pcpu_devices);
+
 typedef long (*sys_call_ptr_t)(struct pt_regs *regs);
 
+static __always_inline struct pcpu *this_pcpu(void)
+{
+	return (struct pcpu *)(get_lowcore()->pcpu);
+}
+
 static __always_inline void set_cpu_flag(int flag)
 {
-	get_lowcore()->cpu_flags |= (1UL << flag);
+	this_pcpu()->flags |= (1UL << flag);
 }
 
 static __always_inline void clear_cpu_flag(int flag)
 {
-	get_lowcore()->cpu_flags &= ~(1UL << flag);
+	this_pcpu()->flags &= ~(1UL << flag);
 }
 
 static __always_inline bool test_cpu_flag(int flag)
 {
-	return get_lowcore()->cpu_flags & (1UL << flag);
+	return this_pcpu()->flags & (1UL << flag);
 }
 
 static __always_inline bool test_and_set_cpu_flag(int flag)
@@ -81,9 +97,7 @@ static __always_inline bool test_and_clear_cpu_flag(int flag)
  */
 static __always_inline bool test_cpu_flag_of(int flag, int cpu)
 {
-	struct lowcore *lc = lowcore_ptr[cpu];
-
-	return lc->cpu_flags & (1UL << flag);
+	return per_cpu(pcpu_devices, cpu).flags & (1UL << flag);
 }
 
 #define arch_needs_cpu() test_cpu_flag(CIF_NOHZ_DELAY)

arch/s390/kernel/asm-offsets.c

@@ -114,7 +114,7 @@ int main(void)
 	OFFSET(__LC_SAVE_AREA_SYNC, lowcore, save_area_sync);
 	OFFSET(__LC_SAVE_AREA_ASYNC, lowcore, save_area_async);
 	OFFSET(__LC_SAVE_AREA_RESTART, lowcore, save_area_restart);
-	OFFSET(__LC_CPU_FLAGS, lowcore, cpu_flags);
+	OFFSET(__LC_PCPU, lowcore, pcpu);
 	OFFSET(__LC_RETURN_PSW, lowcore, return_psw);
 	OFFSET(__LC_RETURN_MCCK_PSW, lowcore, return_mcck_psw);
 	OFFSET(__LC_SYS_ENTER_TIMER, lowcore, sys_enter_timer);
@@ -186,5 +186,7 @@ int main(void)
 #endif
 	OFFSET(__FTRACE_REGS_PT_REGS, ftrace_regs, regs);
 	DEFINE(__FTRACE_REGS_SIZE, sizeof(struct ftrace_regs));
+
+	OFFSET(__PCPU_FLAGS, pcpu, flags);
 	return 0;
 }

arch/s390/kernel/entry.S

@@ -480,7 +480,8 @@ SYM_CODE_START(mcck_int_handler)
 	clgrjl	%r9,%r14, 4f
 	larl	%r14,.Lsie_leave
 	clgrjhe	%r9,%r14, 4f
-	oi	__LC_CPU_FLAGS+7, _CIF_MCCK_GUEST
+	lg	%r10,__LC_PCPU
+	oi	__PCPU_FLAGS+7(%r10), _CIF_MCCK_GUEST
 4:	BPENTER	__SF_SIE_FLAGS(%r15),_TIF_ISOLATE_BP_GUEST
 	SIEEXIT __SF_SIE_CONTROL(%r15)
 #endif

arch/s390/kernel/setup.c

@@ -406,6 +406,7 @@ static void __init setup_lowcore(void)
 		panic("%s: Failed to allocate %zu bytes align=%zx\n",
 		      __func__, sizeof(*lc), sizeof(*lc));
 
+	lc->pcpu = (unsigned long)per_cpu_ptr(&pcpu_devices, 0);
 	lc->restart_psw.mask = PSW_KERNEL_BITS & ~PSW_MASK_DAT;
 	lc->restart_psw.addr = __pa(restart_int_handler);
 	lc->external_new_psw.mask = PSW_KERNEL_BITS;

arch/s390/kernel/smp.c

@@ -74,16 +74,8 @@ enum {
 	CPU_STATE_CONFIGURED,
 };
 
-struct pcpu {
-	unsigned long ec_mask;		/* bit mask for ec_xxx functions */
-	unsigned long ec_clk;		/* sigp timestamp for ec_xxx */
-	signed char state;		/* physical cpu state */
-	signed char polarization;	/* physical polarization */
-	u16 address;			/* physical cpu address */
-};
-
 static u8 boot_core_type;
-static DEFINE_PER_CPU(struct pcpu, pcpu_devices);
+DEFINE_PER_CPU(struct pcpu, pcpu_devices);
 /*
  * Pointer to the pcpu area of the boot CPU. This is required when a restart
  * interrupt is triggered on an offline CPU. For that case accessing percpu
@@ -264,6 +256,7 @@ static void pcpu_prepare_secondary(struct pcpu *pcpu, int cpu)
 	cpumask_set_cpu(cpu, &init_mm.context.cpu_attach_mask);
 	cpumask_set_cpu(cpu, mm_cpumask(&init_mm));
 	lc->cpu_nr = cpu;
+	lc->pcpu = (unsigned long)pcpu;
 	lc->restart_flags = RESTART_FLAG_CTLREGS;
 	lc->spinlock_lockval = arch_spin_lockval(cpu);
 	lc->spinlock_index = 0;
@@ -924,6 +917,7 @@ void __cpu_die(unsigned int cpu)
 	pcpu_free_lowcore(pcpu, cpu);
 	cpumask_clear_cpu(cpu, mm_cpumask(&init_mm));
 	cpumask_clear_cpu(cpu, &init_mm.context.cpu_attach_mask);
+	pcpu->flags = 0;
 }
 
 void __noreturn cpu_die(void)
@@ -959,10 +953,13 @@ void __init smp_prepare_cpus(unsigned int max_cpus)
 
 void __init smp_prepare_boot_cpu(void)
 {
+	struct lowcore *lc = get_lowcore();
+
 	WARN_ON(!cpu_present(0) || !cpu_online(0));
+	lc->percpu_offset = __per_cpu_offset[0];
 	ipl_pcpu = per_cpu_ptr(&pcpu_devices, 0);
 	ipl_pcpu->state = CPU_STATE_CONFIGURED;
-	get_lowcore()->percpu_offset = __per_cpu_offset[0];
+	lc->pcpu = (unsigned long)ipl_pcpu;
 	smp_cpu_set_polarization(0, POLARIZATION_UNKNOWN);
 }