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>

6 files changed, 34 insertions, 20 deletions

diff --git a/arch/s390/include/asm/lowcore.h b/arch/s390/include/asm/lowcore.h
index c724e71e1785..bce3a69ab2a3 100644
--- a/arch/s390/include/asm/lowcore.h
+++ b/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 */
diff --git a/arch/s390/include/asm/processor.h b/arch/s390/include/asm/processor.h
index c87cf2b8e81a..5debb12614ad 100644
--- a/arch/s390/include/asm/processor.h
+++ b/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)
diff --git a/arch/s390/kernel/asm-offsets.c b/arch/s390/kernel/asm-offsets.c
index 26bb45d0e6f1..58fc6b93b475 100644
--- a/arch/s390/kernel/asm-offsets.c
+++ b/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;
 }
diff --git a/arch/s390/kernel/entry.S b/arch/s390/kernel/entry.S
index 454b6b92c7f8..fa58bd2c48c9 100644
--- a/arch/s390/kernel/entry.S
+++ b/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
diff --git a/arch/s390/kernel/setup.c b/arch/s390/kernel/setup.c
index 1faba11d5f0b..178daf4e3563 100644
--- a/arch/s390/kernel/setup.c
+++ b/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;
diff --git a/arch/s390/kernel/smp.c b/arch/s390/kernel/smp.c
index b36b089b9a26..fbba37ec53cf 100644
--- a/arch/s390/kernel/smp.c
+++ b/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);
 }