s390: convert to generic entry

This patch converts s390 to use the generic entry infrastructure from
kernel/entry/*.

There are a few special things on s390:

- PIF_PER_TRAP is moved to TIF_PER_TRAP as the generic code doesn't
  know about our PIF flags in exit_to_user_mode_loop().

- The old code had several ways to restart syscalls:

  a) PIF_SYSCALL_RESTART, which was only set during execve to force a
     restart after upgrading a process (usually qemu-kvm) to pgste page
     table extensions.

  b) PIF_SYSCALL, which is set by do_signal() to indicate that the
     current syscall should be restarted. This is changed so that
     do_signal() now also uses PIF_SYSCALL_RESTART. Continuing to use
     PIF_SYSCALL doesn't work with the generic code, and changing it
     to PIF_SYSCALL_RESTART makes PIF_SYSCALL and PIF_SYSCALL_RESTART
     more unique.

- On s390 calling sys_sigreturn or sys_rt_sigreturn is implemented by
executing a svc instruction on the process stack which causes a fault.
While handling that fault the fault code sets PIF_SYSCALL to hand over
processing to the syscall code on exit to usermode.

The patch introduces PIF_SYSCALL_RET_SET, which is set if ptrace sets
a return value for a syscall. The s390x ptrace ABI uses r2 both for the
syscall number and return value, so ptrace cannot set the syscall number +
return value at the same time. The flag makes handling that a bit easier.
do_syscall() will just skip executing the syscall if PIF_SYSCALL_RET_SET
is set.

CONFIG_DEBUG_ASCE was removd in favour of the generic CONFIG_DEBUG_ENTRY.
CR1/7/13 will be checked both on kernel entry and exit to contain the
correct asces.
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

arch/s390/Kconfig

@@ -123,6 +123,7 @@ config S390
 	select GENERIC_ALLOCATOR
 	select GENERIC_CPU_AUTOPROBE
 	select GENERIC_CPU_VULNERABILITIES
+	select GENERIC_ENTRY
 	select GENERIC_FIND_FIRST_BIT
 	select GENERIC_GETTIMEOFDAY
 	select GENERIC_PTDUMP

arch/s390/Kconfig.debug

@@ -6,10 +6,12 @@ config TRACE_IRQFLAGS_SUPPORT
 config EARLY_PRINTK
 	def_bool y
 
-config DEBUG_USER_ASCE
-	bool "Debug User ASCE"
+config DEBUG_ENTRY
+	bool "Debug low-level entry code"
+	depends on DEBUG_KERNEL
 	help
-	  Check on exit to user space that address space control
-	  elements are setup correctly.
+	  This option enables sanity checks in s390 low-level entry code.
+	  Some of these sanity checks may slow down kernel entries and
+	  exits or otherwise impact performance.
 
 	  If unsure, say N.

arch/s390/configs/debug_defconfig

@@ -833,7 +833,6 @@ CONFIG_BPF_KPROBE_OVERRIDE=y
 CONFIG_HIST_TRIGGERS=y
 CONFIG_FTRACE_STARTUP_TEST=y
 # CONFIG_EVENT_TRACE_STARTUP_TEST is not set
-CONFIG_DEBUG_USER_ASCE=y
 CONFIG_NOTIFIER_ERROR_INJECTION=m
 CONFIG_NETDEV_NOTIFIER_ERROR_INJECT=m
 CONFIG_FAULT_INJECTION=y
@@ -857,3 +856,4 @@ CONFIG_PERCPU_TEST=m
 CONFIG_ATOMIC64_SELFTEST=y
 CONFIG_TEST_BITOPS=m
 CONFIG_TEST_BPF=m
+CONFIG_DEBUG_ENTRY=y

arch/s390/configs/defconfig

@@ -781,7 +781,6 @@ CONFIG_FTRACE_SYSCALLS=y
 CONFIG_BLK_DEV_IO_TRACE=y
 CONFIG_BPF_KPROBE_OVERRIDE=y
 CONFIG_HIST_TRIGGERS=y
-CONFIG_DEBUG_USER_ASCE=y
 CONFIG_LKDTM=m
 CONFIG_PERCPU_TEST=m
 CONFIG_ATOMIC64_SELFTEST=y

arch/s390/include/asm/cputime.h

@@ -35,4 +35,6 @@ u64 arch_cpu_idle_time(int cpu);
 
 #define arch_idle_time(cpu) arch_cpu_idle_time(cpu)
 
+void account_idle_time_irq(void);
+
 #endif /* _S390_CPUTIME_H */

arch/s390/include/asm/elf.h

@@ -233,8 +233,7 @@ extern char elf_platform[];
 do {								\
 	set_personality(PER_LINUX |				\
 		(current->personality & (~PER_MASK)));		\
-	current->thread.sys_call_table =			\
-		(unsigned long) &sys_call_table;		\
+	current->thread.sys_call_table = sys_call_table;	\
 } while (0)
 #else /* CONFIG_COMPAT */
 #define SET_PERSONALITY(ex)					\
@@ -245,11 +244,11 @@ do {								\
 	if ((ex).e_ident[EI_CLASS] == ELFCLASS32) {		\
 		set_thread_flag(TIF_31BIT);			\
 		current->thread.sys_call_table =		\
-			(unsigned long)	&sys_call_table_emu;	\
+			sys_call_table_emu;			\
 	} else {						\
 		clear_thread_flag(TIF_31BIT);			\
 		current->thread.sys_call_table =		\
-			(unsigned long) &sys_call_table;	\
+			sys_call_table;				\
 	}							\
 } while (0)
 #endif /* CONFIG_COMPAT */

arch/s390/include/asm/entry-common.h

+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef ARCH_S390_ENTRY_COMMON_H
+#define ARCH_S390_ENTRY_COMMON_H
+
+#include <linux/sched.h>
+#include <linux/audit.h>
+#include <linux/tracehook.h>
+#include <linux/processor.h>
+#include <linux/uaccess.h>
+#include <asm/fpu/api.h>
+
+#define ARCH_EXIT_TO_USER_MODE_WORK (_TIF_GUARDED_STORAGE | _TIF_PER_TRAP)
+
+void do_per_trap(struct pt_regs *regs);
+void do_syscall(struct pt_regs *regs);
+
+typedef void (*pgm_check_func)(struct pt_regs *regs);
+
+extern pgm_check_func pgm_check_table[128];
+
+#ifdef CONFIG_DEBUG_ENTRY
+static __always_inline void arch_check_user_regs(struct pt_regs *regs)
+{
+	debug_user_asce(0);
+}
+
+#define arch_check_user_regs arch_check_user_regs
+#endif /* CONFIG_DEBUG_ENTRY */
+
+static __always_inline void arch_exit_to_user_mode_work(struct pt_regs *regs,
+							unsigned long ti_work)
+{
+	if (ti_work & _TIF_PER_TRAP) {
+		clear_thread_flag(TIF_PER_TRAP);
+		do_per_trap(regs);
+	}
+
+	if (ti_work & _TIF_GUARDED_STORAGE)
+		gs_load_bc_cb(regs);
+}
+
+#define arch_exit_to_user_mode_work arch_exit_to_user_mode_work
+
+static __always_inline void arch_exit_to_user_mode(void)
+{
+	if (test_cpu_flag(CIF_FPU))
+		__load_fpu_regs();
+
+	if (IS_ENABLED(CONFIG_DEBUG_ENTRY))
+		debug_user_asce(1);
+}
+
+#define arch_exit_to_user_mode arch_exit_to_user_mode
+
+static inline bool on_thread_stack(void)
+{
+	return !(((unsigned long)(current->stack) ^ current_stack_pointer()) & ~(THREAD_SIZE - 1));
+}
+
+#endif

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

@@ -47,6 +47,8 @@
 #include <linux/preempt.h>
 
 void save_fpu_regs(void);
+void load_fpu_regs(void);
+void __load_fpu_regs(void);
 
 static inline int test_fp_ctl(u32 fpc)
 {

arch/s390/include/asm/idle.h

@@ -20,11 +20,13 @@ struct s390_idle_data {
 	unsigned long long clock_idle_exit;
 	unsigned long long timer_idle_enter;
 	unsigned long long timer_idle_exit;
+	unsigned long mt_cycles_enter[8];
 };
 
 extern struct device_attribute dev_attr_idle_count;
 extern struct device_attribute dev_attr_idle_time_us;
 
-void psw_idle(struct s390_idle_data *, unsigned long);
+void psw_idle(struct s390_idle_data *data, unsigned long psw_mask);
+void psw_idle_exit(void);
 
 #endif /* _S390_IDLE_H */

arch/s390/include/asm/lowcore.h

@@ -81,8 +81,8 @@ struct lowcore {
 	psw_t	return_mcck_psw;		/* 0x02a0 */
 
 	/* CPU accounting and timing values. */
-	__u64	sync_enter_timer;		/* 0x02b0 */
-	__u64	async_enter_timer;		/* 0x02b8 */
+	__u64	sys_enter_timer;		/* 0x02b0 */
+	__u8	pad_0x02b8[0x02c0-0x02b8];	/* 0x02b8 */
 	__u64	mcck_enter_timer;		/* 0x02c0 */
 	__u64	exit_timer;			/* 0x02c8 */
 	__u64	user_timer;			/* 0x02d0 */

arch/s390/include/asm/nmi.h

@@ -99,6 +99,7 @@ int nmi_alloc_per_cpu(struct lowcore *lc);
 void nmi_free_per_cpu(struct lowcore *lc);
 
 void s390_handle_mcck(void);
+void __s390_handle_mcck(void);
 int s390_do_machine_check(struct pt_regs *regs);
 
 #endif /* __ASSEMBLY__ */

arch/s390/include/asm/processor.h

@@ -38,6 +38,11 @@
 #include <asm/runtime_instr.h>
 #include <asm/fpu/types.h>
 #include <asm/fpu/internal.h>
+#include <asm/irqflags.h>
+
+typedef long (*sys_call_ptr_t)(unsigned long, unsigned long,
+			       unsigned long, unsigned long,
+			       unsigned long, unsigned long);
 
 static inline void set_cpu_flag(int flag)
 {
@@ -107,11 +112,12 @@ struct thread_struct {
 	unsigned long system_timer;		/* task cputime in kernel space */
 	unsigned long hardirq_timer;		/* task cputime in hardirq context */
 	unsigned long softirq_timer;		/* task cputime in softirq context */
-	unsigned long sys_call_table;	/* system call table address */
+	const sys_call_ptr_t *sys_call_table;	/* system call table address */
 	unsigned long gmap_addr;		/* address of last gmap fault. */
 	unsigned int gmap_write_flag;		/* gmap fault write indication */
 	unsigned int gmap_int_code;		/* int code of last gmap fault */
 	unsigned int gmap_pfault;		/* signal of a pending guest pfault */
+
 	/* Per-thread information related to debugging */
 	struct per_regs per_user;		/* User specified PER registers */
 	struct per_event per_event;		/* Cause of the last PER trap */
@@ -184,6 +190,7 @@ static inline void release_thread(struct task_struct *tsk) { }
 
 /* Free guarded storage control block */
 void guarded_storage_release(struct task_struct *tsk);
+void gs_load_bc_cb(struct pt_regs *regs);
 
 unsigned long get_wchan(struct task_struct *p);
 #define task_pt_regs(tsk) ((struct pt_regs *) \
@@ -324,6 +331,11 @@ extern void memcpy_absolute(void *, void *, size_t);
 extern int s390_isolate_bp(void);
 extern int s390_isolate_bp_guest(void);
 
+static __always_inline bool regs_irqs_disabled(struct pt_regs *regs)
+{
+	return arch_irqs_disabled_flags(regs->psw.mask);
+}
+
 #endif /* __ASSEMBLY__ */
 
 #endif /* __ASM_S390_PROCESSOR_H */

arch/s390/include/asm/ptrace.h

@@ -11,13 +11,13 @@
 #include <uapi/asm/ptrace.h>
 
 #define PIF_SYSCALL		0	/* inside a system call */
-#define PIF_PER_TRAP		1	/* deliver sigtrap on return to user */
-#define PIF_SYSCALL_RESTART	2	/* restart the current system call */
+#define PIF_SYSCALL_RESTART	1	/* restart the current system call */
+#define PIF_SYSCALL_RET_SET	2	/* return value was set via ptrace */
 #define PIF_GUEST_FAULT		3	/* indicates program check in sie64a */
 
 #define _PIF_SYSCALL		BIT(PIF_SYSCALL)
-#define _PIF_PER_TRAP		BIT(PIF_PER_TRAP)
 #define _PIF_SYSCALL_RESTART	BIT(PIF_SYSCALL_RESTART)
+#define _PIF_SYSCALL_RET_SET	BIT(PIF_SYSCALL_RET_SET)
 #define _PIF_GUEST_FAULT	BIT(PIF_GUEST_FAULT)
 
 #ifndef __ASSEMBLY__
@@ -68,6 +68,9 @@ enum {
 	&(*(struct psw_bits *)(&(__psw)));	\
 }))
 
+#define PGM_INT_CODE_MASK	0x7f
+#define PGM_INT_CODE_PER	0x80
+
 /*
  * The pt_regs struct defines the way the registers are stored on
  * the stack during a system call.

arch/s390/include/asm/syscall.h

@@ -14,8 +14,8 @@
 #include <linux/err.h>
 #include <asm/ptrace.h>
 
-extern const unsigned long sys_call_table[];
-extern const unsigned long sys_call_table_emu[];
+extern const sys_call_ptr_t sys_call_table[];
+extern const sys_call_ptr_t sys_call_table_emu[];
 
 static inline long syscall_get_nr(struct task_struct *task,
 				  struct pt_regs *regs)
@@ -56,6 +56,7 @@ static inline void syscall_set_return_value(struct task_struct *task,
 					    struct pt_regs *regs,
 					    int error, long val)
 {
+	set_pt_regs_flag(regs, PIF_SYSCALL_RET_SET);
 	regs->gprs[2] = error ? error : val;
 }
 
@@ -97,4 +98,10 @@ static inline int syscall_get_arch(struct task_struct *task)
 #endif
 	return AUDIT_ARCH_S390X;
 }
+
+static inline bool arch_syscall_is_vdso_sigreturn(struct pt_regs *regs)
+{
+	return false;
+}
+
 #endif	/* _ASM_SYSCALL_H */

arch/s390/include/asm/thread_info.h

@@ -36,6 +36,7 @@
  */
 struct thread_info {
 	unsigned long		flags;		/* low level flags */
+	unsigned long		syscall_work;	/* SYSCALL_WORK_ flags */
 };
 
 /*
@@ -68,6 +69,7 @@ void arch_setup_new_exec(void);
 #define TIF_NOTIFY_SIGNAL	7	/* signal notifications exist */
 #define TIF_ISOLATE_BP		8	/* Run process with isolated BP */
 #define TIF_ISOLATE_BP_GUEST	9	/* Run KVM guests with isolated BP */
+#define TIF_PER_TRAP		10	/* Need to handle PER trap on exit to usermode */
 
 #define TIF_31BIT		16	/* 32bit process */
 #define TIF_MEMDIE		17	/* is terminating due to OOM killer */
@@ -91,6 +93,7 @@ void arch_setup_new_exec(void);
 #define _TIF_PATCH_PENDING	BIT(TIF_PATCH_PENDING)
 #define _TIF_ISOLATE_BP		BIT(TIF_ISOLATE_BP)
 #define _TIF_ISOLATE_BP_GUEST	BIT(TIF_ISOLATE_BP_GUEST)
+#define _TIF_PER_TRAP		BIT(TIF_PER_TRAP)
 
 #define _TIF_31BIT		BIT(TIF_31BIT)
 #define _TIF_SINGLE_STEP	BIT(TIF_SINGLE_STEP)

arch/s390/include/asm/uaccess.h

@@ -18,7 +18,7 @@
 #include <asm/extable.h>
 #include <asm/facility.h>
 
-void debug_user_asce(void);
+void debug_user_asce(int exit);
 
 static inline int __range_ok(unsigned long addr, unsigned long size)
 {

arch/s390/include/asm/vtime.h

@@ -4,4 +4,18 @@
 
 #define __ARCH_HAS_VTIME_TASK_SWITCH
 
+static inline void update_timer_sys(void)
+{
+	S390_lowcore.system_timer += S390_lowcore.last_update_timer - S390_lowcore.exit_timer;
+	S390_lowcore.user_timer += S390_lowcore.exit_timer - S390_lowcore.sys_enter_timer;
+	S390_lowcore.last_update_timer = S390_lowcore.sys_enter_timer;
+}
+
+static inline void update_timer_mcck(void)
+{
+	S390_lowcore.system_timer += S390_lowcore.last_update_timer - S390_lowcore.exit_timer;
+	S390_lowcore.user_timer += S390_lowcore.exit_timer - S390_lowcore.mcck_enter_timer;
+	S390_lowcore.last_update_timer = S390_lowcore.mcck_enter_timer;
+}
+
 #endif /* _S390_VTIME_H */

arch/s390/include/uapi/asm/ptrace.h

@@ -180,7 +180,8 @@
 
 
 #define PTRACE_OLDSETOPTIONS		21
-
+#define PTRACE_SYSEMU			31
+#define PTRACE_SYSEMU_SINGLESTEP	32
 #ifndef __ASSEMBLY__
 #include <linux/stddef.h>
 #include <linux/types.h>

arch/s390/kernel/Makefile

@@ -34,7 +34,7 @@ CFLAGS_dumpstack.o	+= -fno-optimize-sibling-calls
 CFLAGS_unwind_bc.o	+= -fno-optimize-sibling-calls
 
 obj-y	:= traps.o time.o process.o base.o early.o setup.o idle.o vtime.o
-obj-y	+= processor.o sys_s390.o ptrace.o signal.o cpcmd.o ebcdic.o nmi.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
 obj-y	+= sysinfo.o lgr.o os_info.o machine_kexec.o pgm_check.o
 obj-y	+= runtime_instr.o cache.o fpu.o dumpstack.o guarded_storage.o sthyi.o

arch/s390/kernel/asm-offsets.c

@@ -26,26 +26,14 @@ int main(void)
 	BLANK();
 	/* thread struct offsets */
 	OFFSET(__THREAD_ksp, thread_struct, ksp);
-	OFFSET(__THREAD_sysc_table,  thread_struct, sys_call_table);
-	OFFSET(__THREAD_last_break, thread_struct, last_break);
-	OFFSET(__THREAD_FPU_fpc, thread_struct, fpu.fpc);
-	OFFSET(__THREAD_FPU_regs, thread_struct, fpu.regs);
-	OFFSET(__THREAD_per_cause, thread_struct, per_event.cause);
-	OFFSET(__THREAD_per_address, thread_struct, per_event.address);
-	OFFSET(__THREAD_per_paid, thread_struct, per_event.paid);
-	OFFSET(__THREAD_trap_tdb, thread_struct, trap_tdb);
 	BLANK();
 	/* thread info offsets */
 	OFFSET(__TI_flags, task_struct, thread_info.flags);
 	BLANK();
 	/* pt_regs offsets */
-	OFFSET(__PT_ARGS, pt_regs, args);
 	OFFSET(__PT_PSW, pt_regs, psw);
 	OFFSET(__PT_GPRS, pt_regs, gprs);
 	OFFSET(__PT_ORIG_GPR2, pt_regs, orig_gpr2);
-	OFFSET(__PT_INT_CODE, pt_regs, int_code);
-	OFFSET(__PT_INT_PARM, pt_regs, int_parm);
-	OFFSET(__PT_INT_PARM_LONG, pt_regs, int_parm_long);
 	OFFSET(__PT_FLAGS, pt_regs, flags);
 	OFFSET(__PT_CR1, pt_regs, cr1);
 	DEFINE(__PT_SIZE, sizeof(struct pt_regs));
@@ -64,6 +52,7 @@ int main(void)
 	OFFSET(__CLOCK_IDLE_EXIT, s390_idle_data, clock_idle_exit);
 	OFFSET(__TIMER_IDLE_ENTER, s390_idle_data, timer_idle_enter);
 	OFFSET(__TIMER_IDLE_EXIT, s390_idle_data, timer_idle_exit);
+	OFFSET(__MT_CYCLES_ENTER, s390_idle_data, mt_cycles_enter);
 	BLANK();
 	/* hardware defined lowcore locations 0x000 - 0x1ff */
 	OFFSET(__LC_EXT_PARAMS, lowcore, ext_params);
@@ -115,13 +104,9 @@ int main(void)
 	OFFSET(__LC_CPU_FLAGS, lowcore, cpu_flags);
 	OFFSET(__LC_RETURN_PSW, lowcore, return_psw);
 	OFFSET(__LC_RETURN_MCCK_PSW, lowcore, return_mcck_psw);
-	OFFSET(__LC_SYNC_ENTER_TIMER, lowcore, sync_enter_timer);
-	OFFSET(__LC_ASYNC_ENTER_TIMER, lowcore, async_enter_timer);
+	OFFSET(__LC_SYS_ENTER_TIMER, lowcore, sys_enter_timer);
 	OFFSET(__LC_MCCK_ENTER_TIMER, lowcore, mcck_enter_timer);
 	OFFSET(__LC_EXIT_TIMER, lowcore, exit_timer);
-	OFFSET(__LC_USER_TIMER, lowcore, user_timer);
-	OFFSET(__LC_SYSTEM_TIMER, lowcore, system_timer);
-	OFFSET(__LC_STEAL_TIMER, lowcore, steal_timer);
 	OFFSET(__LC_LAST_UPDATE_TIMER, lowcore, last_update_timer);
 	OFFSET(__LC_LAST_UPDATE_CLOCK, lowcore, last_update_clock);
 	OFFSET(__LC_INT_CLOCK, lowcore, int_clock);

arch/s390/kernel/compat_signal.c

@@ -118,6 +118,7 @@ static int restore_sigregs32(struct pt_regs *regs,_sigregs32 __user *sregs)
 	fpregs_load((_s390_fp_regs *) &user_sregs.fpregs, &current->thread.fpu);
 
 	clear_pt_regs_flag(regs, PIF_SYSCALL); /* No longer in a system call */
+	clear_pt_regs_flag(regs, PIF_SYSCALL_RESTART);
 	return 0;
 }
 

arch/s390/kernel/entry.h

@@ -17,8 +17,9 @@ void io_int_handler(void);
 void mcck_int_handler(void);
 void restart_int_handler(void);
 
-asmlinkage long do_syscall_trace_enter(struct pt_regs *regs);
-asmlinkage void do_syscall_trace_exit(struct pt_regs *regs);
+void __ret_from_fork(struct task_struct *prev, struct pt_regs *regs);
+void __do_pgm_check(struct pt_regs *regs);
+void __do_syscall(struct pt_regs *regs, int per_trap);
 
 void do_protection_exception(struct pt_regs *regs);
 void do_dat_exception(struct pt_regs *regs);
@@ -48,9 +49,7 @@ void translation_exception(struct pt_regs *regs);
 void vector_exception(struct pt_regs *regs);
 void monitor_event_exception(struct pt_regs *regs);
 
-void do_per_trap(struct pt_regs *regs);
 void do_report_trap(struct pt_regs *regs, int si_signo, int si_code, char *str);
-void syscall_trace(struct pt_regs *regs, int entryexit);
 void kernel_stack_overflow(struct pt_regs * regs);
 void do_signal(struct pt_regs *regs);
 void handle_signal32(struct ksignal *ksig, sigset_t *oldset,
@@ -58,7 +57,8 @@ void handle_signal32(struct ksignal *ksig, sigset_t *oldset,
 void do_notify_resume(struct pt_regs *regs);
 
 void __init init_IRQ(void);
-void do_IRQ(struct pt_regs *regs, int irq);
+void do_io_irq(struct pt_regs *regs);
+void do_ext_irq(struct pt_regs *regs);
 void do_restart(void);
 void __init startup_init(void);
 void die(struct pt_regs *regs, const char *str);
@@ -82,8 +82,6 @@ long sys_s390_sthyi(unsigned long function_code, void __user *buffer, u64 __user
 
 DECLARE_PER_CPU(u64, mt_cycles[8]);
 
-void gs_load_bc_cb(struct pt_regs *regs);
-
 unsigned long stack_alloc(void);
 void stack_free(unsigned long stack);
 

arch/s390/kernel/fpu.c

@@ -175,3 +175,91 @@ void __kernel_fpu_end(struct kernel_fpu *state, u32 flags)
 		: "1", "cc");
 }
 EXPORT_SYMBOL(__kernel_fpu_end);
+
+void __load_fpu_regs(void)
+{
+	struct fpu *state = &current->thread.fpu;
+	unsigned long *regs = current->thread.fpu.regs;
+
+	asm volatile("lfpc %0" : : "Q" (state->fpc));
+	if (likely(MACHINE_HAS_VX)) {
+		asm volatile("lgr	1,%0\n"
+			     "VLM	0,15,0,1\n"
+			     "VLM	16,31,256,1\n"
+			     :
+			     : "d" (regs)
+			     : "1", "cc", "memory");
+	} else {
+		asm volatile("ld 0,%0" : : "Q" (regs[0]));
+		asm volatile("ld 1,%0" : : "Q" (regs[1]));
+		asm volatile("ld 2,%0" : : "Q" (regs[2]));
+		asm volatile("ld 3,%0" : : "Q" (regs[3]));
+		asm volatile("ld 4,%0" : : "Q" (regs[4]));
+		asm volatile("ld 5,%0" : : "Q" (regs[5]));
+		asm volatile("ld 6,%0" : : "Q" (regs[6]));
+		asm volatile("ld 7,%0" : : "Q" (regs[7]));
+		asm volatile("ld 8,%0" : : "Q" (regs[8]));
+		asm volatile("ld 9,%0" : : "Q" (regs[9]));
+		asm volatile("ld 10,%0" : : "Q" (regs[10]));
+		asm volatile("ld 11,%0" : : "Q" (regs[11]));
+		asm volatile("ld 12,%0" : : "Q" (regs[12]));
+		asm volatile("ld 13,%0" : : "Q" (regs[13]));
+		asm volatile("ld 14,%0" : : "Q" (regs[14]));
+		asm volatile("ld 15,%0" : : "Q" (regs[15]));
+	}
+	clear_cpu_flag(CIF_FPU);
+}
+EXPORT_SYMBOL(__load_fpu_regs);
+
+void load_fpu_regs(void)
+{
+	raw_local_irq_disable();
+	__load_fpu_regs();
+	raw_local_irq_enable();
+}
+EXPORT_SYMBOL(load_fpu_regs);
+
+void save_fpu_regs(void)
+{
+	unsigned long flags, *regs;
+	struct fpu *state;
+
+	local_irq_save(flags);
+
+	if (test_cpu_flag(CIF_FPU))
+		goto out;
+
+	state = &current->thread.fpu;
+	regs = current->thread.fpu.regs;
+
+	asm volatile("stfpc %0" : "=Q" (state->fpc));
+	if (likely(MACHINE_HAS_VX)) {
+		asm volatile("lgr	1,%0\n"
+			     "VSTM	0,15,0,1\n"
+			     "VSTM	16,31,256,1\n"
+			     :
+			     : "d" (regs)
+			     : "1", "cc", "memory");
+	} else {
+		asm volatile("std 0,%0" : "=Q" (regs[0]));
+		asm volatile("std 1,%0" : "=Q" (regs[1]));
+		asm volatile("std 2,%0" : "=Q" (regs[2]));
+		asm volatile("std 3,%0" : "=Q" (regs[3]));
+		asm volatile("std 4,%0" : "=Q" (regs[4]));
+		asm volatile("std 5,%0" : "=Q" (regs[5]));
+		asm volatile("std 6,%0" : "=Q" (regs[6]));
+		asm volatile("std 7,%0" : "=Q" (regs[7]));
+		asm volatile("std 8,%0" : "=Q" (regs[8]));
+		asm volatile("std 9,%0" : "=Q" (regs[9]));
+		asm volatile("std 10,%0" : "=Q" (regs[10]));
+		asm volatile("std 11,%0" : "=Q" (regs[11]));
+		asm volatile("std 12,%0" : "=Q" (regs[12]));
+		asm volatile("std 13,%0" : "=Q" (regs[13]));
+		asm volatile("std 14,%0" : "=Q" (regs[14]));
+		asm volatile("std 15,%0" : "=Q" (regs[15]));
+	}
+	set_cpu_flag(CIF_FPU);
+out:
+	local_irq_restore(flags);
+}
+EXPORT_SYMBOL(save_fpu_regs);

arch/s390/kernel/idle.c

@@ -14,12 +14,36 @@
 #include <linux/cpu.h>
 #include <linux/sched/cputime.h>
 #include <trace/events/power.h>
+#include <asm/cpu_mf.h>
 #include <asm/nmi.h>
 #include <asm/smp.h>
 #include "entry.h"
 
 static DEFINE_PER_CPU(struct s390_idle_data, s390_idle);
 
+void account_idle_time_irq(void)
+{
+	struct s390_idle_data *idle = this_cpu_ptr(&s390_idle);
+	u64 cycles_new[8];
+	int i;
+
+	clear_cpu_flag(CIF_ENABLED_WAIT);
+	if (smp_cpu_mtid) {
+		stcctm(MT_DIAG, smp_cpu_mtid, cycles_new);
+		for (i = 0; i < smp_cpu_mtid; i++)
+			this_cpu_add(mt_cycles[i], cycles_new[i] - idle->mt_cycles_enter[i]);
+	}
+
+	idle->clock_idle_exit = S390_lowcore.int_clock;
+	idle->timer_idle_exit = S390_lowcore.sys_enter_timer;
+
+	S390_lowcore.steal_timer += idle->clock_idle_enter - S390_lowcore.last_update_clock;
+	S390_lowcore.last_update_clock = idle->clock_idle_exit;
+
+	S390_lowcore.system_timer += S390_lowcore.last_update_timer - idle->timer_idle_enter;
+	S390_lowcore.last_update_timer = idle->timer_idle_exit;
+}
+
 void arch_cpu_idle(void)
 {
 	struct s390_idle_data *idle = this_cpu_ptr(&s390_idle);

arch/s390/kernel/irq.c

@@ -21,6 +21,7 @@
 #include <linux/init.h>
 #include <linux/cpu.h>
 #include <linux/irq.h>
+#include <linux/entry-common.h>
 #include <asm/irq_regs.h>
 #include <asm/cputime.h>
 #include <asm/lowcore.h>
@@ -95,19 +96,97 @@ static const struct irq_class irqclass_sub_desc[] = {
 	{.irq = CPU_RST,    .name = "RST", .desc = "[CPU] CPU Restart"},
 };
 
-void do_IRQ(struct pt_regs *regs, int irq)
+static void do_IRQ(struct pt_regs *regs, int irq)
 {
-	struct pt_regs *old_regs;
-
-	old_regs = set_irq_regs(regs);
-	irq_enter();
 	if (tod_after_eq(S390_lowcore.int_clock,
 			 S390_lowcore.clock_comparator))
 		/* Serve timer interrupts first. */
 		clock_comparator_work();
 	generic_handle_irq(irq);
+}
+
+static int on_async_stack(void)
+{
+	unsigned long frame = current_frame_address();
+
+	return !!!((S390_lowcore.async_stack - frame) >> (PAGE_SHIFT + THREAD_SIZE_ORDER));
+}
+
+static void do_irq_async(struct pt_regs *regs, int irq)
+{
+	if (on_async_stack())
+		do_IRQ(regs, irq);
+	else
+		CALL_ON_STACK(do_IRQ, S390_lowcore.async_stack, 2, regs, irq);
+}
+
+static int irq_pending(struct pt_regs *regs)
+{
+	int cc;
+
+	asm volatile("tpi 0\n"
+		     "ipm %0" : "=d" (cc) : : "cc");
+	return cc >> 28;
+}
+
+void noinstr do_io_irq(struct pt_regs *regs)
+{
+	irqentry_state_t state = irqentry_enter(regs);
+	struct pt_regs *old_regs = set_irq_regs(regs);
+	int from_idle;
+
+	irq_enter();
+
+	if (user_mode(regs))
+		update_timer_sys();
+
+	from_idle = !user_mode(regs) && regs->psw.addr == (unsigned long)psw_idle_exit;
+	if (from_idle)
+		account_idle_time_irq();
+
+	do {
+		memcpy(&regs->int_code, &S390_lowcore.subchannel_id, 12);
+		if (S390_lowcore.io_int_word & BIT(31))
+			do_irq_async(regs, THIN_INTERRUPT);
+		else
+			do_irq_async(regs, IO_INTERRUPT);
+	} while (MACHINE_IS_LPAR && irq_pending(regs));
+
+	irq_exit();
+	set_irq_regs(old_regs);
+	irqentry_exit(regs, state);
+
+	if (from_idle)
+		regs->psw.mask &= ~(PSW_MASK_EXT | PSW_MASK_IO | PSW_MASK_WAIT);
+}
+
+void noinstr do_ext_irq(struct pt_regs *regs)
+{
+	irqentry_state_t state = irqentry_enter(regs);
+	struct pt_regs *old_regs = set_irq_regs(regs);
+	int from_idle;
+
+	irq_enter();
+
+	if (user_mode(regs))
+		update_timer_sys();
+
+	memcpy(&regs->int_code, &S390_lowcore.ext_cpu_addr, 4);
+	regs->int_parm = S390_lowcore.ext_params;
+	regs->int_parm_long = *(unsigned long *)S390_lowcore.ext_params2;
+
+	from_idle = !user_mode(regs) && regs->psw.addr == (unsigned long)psw_idle_exit;
+	if (from_idle)
+		account_idle_time_irq();
+
+	do_irq_async(regs, EXT_INTERRUPT);
+
 	irq_exit();
 	set_irq_regs(old_regs);
+	irqentry_exit(regs, state);
+
+	if (from_idle)
+		regs->psw.mask &= ~(PSW_MASK_EXT | PSW_MASK_IO | PSW_MASK_WAIT);
 }
 
 static void show_msi_interrupt(struct seq_file *p, int irq)

arch/s390/kernel/nmi.c

@@ -131,12 +131,11 @@ static notrace void s390_handle_damage(void)
 NOKPROBE_SYMBOL(s390_handle_damage);
 
 /*
- * Main machine check handler function. Will be called with interrupts enabled
- * or disabled and machine checks enabled or disabled.
+ * Main machine check handler function. Will be called with interrupts disabled
+ * and machine checks enabled.
  */
-void s390_handle_mcck(void)
+void __s390_handle_mcck(void)
 {
-	unsigned long flags;
 	struct mcck_struct mcck;
 
 	/*
@@ -144,12 +143,10 @@ void s390_handle_mcck(void)
 	 * machine checks. Afterwards delete the old state and enable machine
 	 * checks again.
 	 */
-	local_irq_save(flags);
 	local_mcck_disable();
 	mcck = *this_cpu_ptr(&cpu_mcck);
 	memset(this_cpu_ptr(&cpu_mcck), 0, sizeof(mcck));
 	local_mcck_enable();
-	local_irq_restore(flags);
 
 	if (mcck.channel_report)
 		crw_handle_channel_report();
@@ -181,8 +178,13 @@ void s390_handle_mcck(void)
 		do_exit(SIGSEGV);
 	}
 }
-EXPORT_SYMBOL_GPL(s390_handle_mcck);
 
+void noinstr s390_handle_mcck(void)
+{
+	trace_hardirqs_off();
+	__s390_handle_mcck();
+	trace_hardirqs_on();
+}
 /*
  * returns 0 if all required registers are available
  * returns 1 otherwise
@@ -344,6 +346,9 @@ int notrace s390_do_machine_check(struct pt_regs *regs)
 	int mcck_pending = 0;
 
 	nmi_enter();
+
+	if (user_mode(regs))
+		update_timer_mcck();
 	inc_irq_stat(NMI_NMI);
 	mci.val = S390_lowcore.mcck_interruption_code;
 	mcck = this_cpu_ptr(&cpu_mcck);

arch/s390/kernel/process.c

@@ -29,6 +29,7 @@
 #include <linux/random.h>
 #include <linux/export.h>
 #include <linux/init_task.h>
+#include <linux/entry-common.h>
 #include <asm/cpu_mf.h>
 #include <asm/io.h>
 #include <asm/processor.h>
@@ -43,9 +44,22 @@
 #include <asm/unwind.h>
 #include "entry.h"
 
-asmlinkage void ret_from_fork(void) asm ("ret_from_fork");
+void ret_from_fork(void) asm("ret_from_fork");
 
-extern void kernel_thread_starter(void);
+void __ret_from_fork(struct task_struct *prev, struct pt_regs *regs)
+{
+	void (*func)(void *arg);
+
+	schedule_tail(prev);
+
+	if (!user_mode(regs)) {
+		/* Kernel thread */
+		func = (void *)regs->gprs[9];
+		func((void *)regs->gprs[10]);
+	}
+	clear_pt_regs_flag(regs, PIF_SYSCALL);
+	syscall_exit_to_user_mode(regs);
+}
 
 void flush_thread(void)
 {
@@ -108,10 +122,12 @@ int copy_thread(unsigned long clone_flags, unsigned long new_stackp,
 	p->thread.last_break = 1;
 
 	frame->sf.back_chain = 0;
+	frame->sf.gprs[5] = (unsigned long)frame + sizeof(struct stack_frame);
+	frame->sf.gprs[6] = (unsigned long)p;
 	/* new return point is ret_from_fork */
-	frame->sf.gprs[8] = (unsigned long) ret_from_fork;
+	frame->sf.gprs[8] = (unsigned long)ret_from_fork;
 	/* fake return stack for resume(), don't go back to schedule */
-	frame->sf.gprs[9] = (unsigned long) frame;
+	frame->sf.gprs[9] = (unsigned long)frame;
 
 	/* Store access registers to kernel stack of new process. */
 	if (unlikely(p->flags & PF_KTHREAD)) {
@@ -120,10 +136,10 @@ int copy_thread(unsigned long clone_flags, unsigned long new_stackp,
 		frame->childregs.psw.mask = PSW_KERNEL_BITS | PSW_MASK_DAT |
 				PSW_MASK_IO | PSW_MASK_EXT | PSW_MASK_MCHECK;
 		frame->childregs.psw.addr =
-				(unsigned long) kernel_thread_starter;
+				(unsigned long)__ret_from_fork;
 		frame->childregs.gprs[9] = new_stackp; /* function */
 		frame->childregs.gprs[10] = arg;
-		frame->childregs.gprs[11] = (unsigned long) do_exit;
+		frame->childregs.gprs[11] = (unsigned long)do_exit;
 		frame->childregs.orig_gpr2 = -1;
 
 		return 0;
@@ -153,7 +169,7 @@ int copy_thread(unsigned long clone_flags, unsigned long new_stackp,
 	return 0;
 }
 
-asmlinkage void execve_tail(void)
+void execve_tail(void)
 {
 	current->thread.fpu.fpc = 0;
 	asm volatile("sfpc %0" : : "d" (0));

arch/s390/kernel/ptrace.c

@@ -7,6 +7,7 @@
  *               Martin Schwidefsky (schwidefsky@de.ibm.com)
  */
 
+#include "asm/ptrace.h"
 #include <linux/kernel.h>
 #include <linux/sched.h>
 #include <linux/sched/task_stack.h>
@@ -37,9 +38,6 @@
 #include "compat_ptrace.h"
 #endif
 
-#define CREATE_TRACE_POINTS
-#include <trace/events/syscalls.h>
-
 void update_cr_regs(struct task_struct *task)
 {
 	struct pt_regs *regs = task_pt_regs(task);
@@ -140,7 +138,7 @@ void ptrace_disable(struct task_struct *task)
 	memset(&task->thread.per_user, 0, sizeof(task->thread.per_user));
 	memset(&task->thread.per_event, 0, sizeof(task->thread.per_event));
 	clear_tsk_thread_flag(task, TIF_SINGLE_STEP);
-	clear_pt_regs_flag(task_pt_regs(task), PIF_PER_TRAP);
+	clear_tsk_thread_flag(task, TIF_PER_TRAP);
 	task->thread.per_flags = 0;
 }
 
@@ -322,25 +320,6 @@ static inline void __poke_user_per(struct task_struct *child,
 		child->thread.per_user.end = data;
 }
 
-static void fixup_int_code(struct task_struct *child, addr_t data)
-{
-	struct pt_regs *regs = task_pt_regs(child);
-	int ilc = regs->int_code >> 16;
-	u16 insn;
-
-	if (ilc > 6)
-		return;
-
-	if (ptrace_access_vm(child, regs->psw.addr - (regs->int_code >> 16),
-			&insn, sizeof(insn), FOLL_FORCE) != sizeof(insn))
-		return;
-
-	/* double check that tracee stopped on svc instruction */
-	if ((insn >> 8) != 0xa)
-		return;
-
-	regs->int_code = 0x20000 | (data & 0xffff);
-}
 /*
  * Write a word to the user area of a process at location addr. This
  * operation does have an additional problem compared to peek_user.
@@ -374,10 +353,12 @@ static int __poke_user(struct task_struct *child, addr_t addr, addr_t data)
 		}
 
 		if (test_pt_regs_flag(regs, PIF_SYSCALL) &&
-			addr == offsetof(struct user, regs.gprs[2]))
-			fixup_int_code(child, data);
-		*(addr_t *)((addr_t) &regs->psw + addr) = data;
+			addr == offsetof(struct user, regs.gprs[2])) {
+			struct pt_regs *regs = task_pt_regs(child);
 
+			regs->int_code = 0x20000 | (data & 0xffff);
+		}
+		*(addr_t *)((addr_t) &regs->psw + addr) = data;
 	} else if (addr < (addr_t) (&dummy->regs.orig_gpr2)) {
 		/*
 		 * access registers are stored in the thread structure
@@ -742,10 +723,12 @@ static int __poke_user_compat(struct task_struct *child,
 			regs->psw.mask = (regs->psw.mask & ~PSW_MASK_BA) |
 				(__u64)(tmp & PSW32_ADDR_AMODE);
 		} else {
-
 			if (test_pt_regs_flag(regs, PIF_SYSCALL) &&
-				addr == offsetof(struct compat_user, regs.gprs[2]))
-				fixup_int_code(child, data);
+				addr == offsetof(struct compat_user, regs.gprs[2])) {
+				struct pt_regs *regs = task_pt_regs(child);
+
+				regs->int_code = 0x20000 | (data & 0xffff);
+			}
 			/* gpr 0-15 */
 			*(__u32*)((addr_t) &regs->psw + addr*2 + 4) = tmp;
 		}
@@ -862,82 +845,6 @@ long compat_arch_ptrace(struct task_struct *child, compat_long_t request,
 }
 #endif
 
-asmlinkage long do_syscall_trace_enter(struct pt_regs *regs)
-{
-	unsigned long mask = -1UL;
-	long ret = -1;
-
-	if (is_compat_task())
-		mask = 0xffffffff;
-
-	/*
-	 * The sysc_tracesys code in entry.S stored the system
-	 * call number to gprs[2].
-	 */
-	if (test_thread_flag(TIF_SYSCALL_TRACE) &&
-	    tracehook_report_syscall_entry(regs)) {
-		/*
-		 * Tracing decided this syscall should not happen. Skip
-		 * the system call and the system call restart handling.
-		 */
-		goto skip;
-	}
-
-#ifdef CONFIG_SECCOMP
-	/* Do the secure computing check after ptrace. */
-	if (unlikely(test_thread_flag(TIF_SECCOMP))) {
-		struct seccomp_data sd;
-
-		if (is_compat_task()) {
-			sd.instruction_pointer = regs->psw.addr & 0x7fffffff;
-			sd.arch = AUDIT_ARCH_S390;
-		} else {
-			sd.instruction_pointer = regs->psw.addr;
-			sd.arch = AUDIT_ARCH_S390X;
-		}
-
-		sd.nr = regs->int_code & 0xffff;
-		sd.args[0] = regs->orig_gpr2 & mask;
-		sd.args[1] = regs->gprs[3] & mask;
-		sd.args[2] = regs->gprs[4] & mask;
-		sd.args[3] = regs->gprs[5] & mask;
-		sd.args[4] = regs->gprs[6] & mask;
-		sd.args[5] = regs->gprs[7] & mask;
-
-		if (__secure_computing(&sd) == -1)
-			goto skip;
-	}
-#endif /* CONFIG_SECCOMP */
-
-	if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT)))
-		trace_sys_enter(regs, regs->int_code & 0xffff);
-
-
-	audit_syscall_entry(regs->int_code & 0xffff, regs->orig_gpr2 & mask,
-			    regs->gprs[3] &mask, regs->gprs[4] &mask,
-			    regs->gprs[5] &mask);
-
-	if ((signed long)regs->gprs[2] >= NR_syscalls) {
-		regs->gprs[2] = -ENOSYS;
-		ret = -ENOSYS;
-	}
-	return regs->gprs[2];
-skip:
-	clear_pt_regs_flag(regs, PIF_SYSCALL);
-	return ret;
-}
-
-asmlinkage void do_syscall_trace_exit(struct pt_regs *regs)
-{
-	audit_syscall_exit(regs);
-
-	if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT)))
-		trace_sys_exit(regs, regs->gprs[2]);
-
-	if (test_thread_flag(TIF_SYSCALL_TRACE))
-		tracehook_report_syscall_exit(regs, 0);
-}
-
 /*
  * user_regset definitions.
  */

arch/s390/kernel/setup.c

@@ -411,8 +411,7 @@ static void __init setup_lowcore_dat_off(void)
 	memcpy(lc->alt_stfle_fac_list, S390_lowcore.alt_stfle_fac_list,
 	       sizeof(lc->alt_stfle_fac_list));
 	nmi_alloc_boot_cpu(lc);
-	lc->sync_enter_timer = S390_lowcore.sync_enter_timer;
-	lc->async_enter_timer = S390_lowcore.async_enter_timer;
+	lc->sys_enter_timer = S390_lowcore.sys_enter_timer;
 	lc->exit_timer = S390_lowcore.exit_timer;
 	lc->user_timer = S390_lowcore.user_timer;
 	lc->system_timer = S390_lowcore.system_timer;

arch/s390/kernel/signal.c

@@ -170,6 +170,7 @@ static int restore_sigregs(struct pt_regs *regs, _sigregs __user *sregs)
 	fpregs_load(&user_sregs.fpregs, &current->thread.fpu);
 
 	clear_pt_regs_flag(regs, PIF_SYSCALL); /* No longer in a system call */
+	clear_pt_regs_flag(regs, PIF_SYSCALL_RESTART);
 	return 0;
 }
 
@@ -459,7 +460,8 @@ static void handle_signal(struct ksignal *ksig, sigset_t *oldset,
  * the kernel can handle, and then we build all the user-level signal handling
  * stack-frames in one go after that.
  */
-void do_signal(struct pt_regs *regs)
+
+void arch_do_signal_or_restart(struct pt_regs *regs, bool has_signal)
 {
 	struct ksignal ksig;
 	sigset_t *oldset = sigmask_to_save();
@@ -472,7 +474,7 @@ void do_signal(struct pt_regs *regs)
 	current->thread.system_call =
 		test_pt_regs_flag(regs, PIF_SYSCALL) ? regs->int_code : 0;
 
-	if (test_thread_flag(TIF_SIGPENDING) && get_signal(&ksig)) {
+	if (has_signal && get_signal(&ksig)) {
 		/* Whee!  Actually deliver the signal.  */
 		if (current->thread.system_call) {
 			regs->int_code = current->thread.system_call;
@@ -498,6 +500,7 @@ void do_signal(struct pt_regs *regs)
 		}
 		/* No longer in a system call */
 		clear_pt_regs_flag(regs, PIF_SYSCALL);
+		clear_pt_regs_flag(regs, PIF_SYSCALL_RESTART);
 		rseq_signal_deliver(&ksig, regs);
 		if (is_compat_task())
 			handle_signal32(&ksig, oldset, regs);
@@ -508,6 +511,7 @@ void do_signal(struct pt_regs *regs)
 
 	/* No handlers present - check for system call restart */
 	clear_pt_regs_flag(regs, PIF_SYSCALL);
+	clear_pt_regs_flag(regs, PIF_SYSCALL_RESTART);
 	if (current->thread.system_call) {
 		regs->int_code = current->thread.system_call;
 		switch (regs->gprs[2]) {
@@ -520,9 +524,9 @@ void do_signal(struct pt_regs *regs)
 		case -ERESTARTNOINTR:
 			/* Restart system call with magic TIF bit. */
 			regs->gprs[2] = regs->orig_gpr2;
-			set_pt_regs_flag(regs, PIF_SYSCALL);
+			set_pt_regs_flag(regs, PIF_SYSCALL_RESTART);
 			if (test_thread_flag(TIF_SINGLE_STEP))
-				clear_pt_regs_flag(regs, PIF_PER_TRAP);
+				clear_thread_flag(TIF_PER_TRAP);
 			break;
 		}
 	}

arch/s390/kernel/smp.c

@@ -499,7 +499,7 @@ static void smp_handle_ext_call(void)
 	if (test_bit(ec_call_function_single, &bits))
 		generic_smp_call_function_single_interrupt();
 	if (test_bit(ec_mcck_pending, &bits))
-		s390_handle_mcck();
+		__s390_handle_mcck();
 }
 
 static void do_ext_call_interrupt(struct ext_code ext_code,

arch/s390/kernel/sys_s390.c → arch/s390/kernel/syscall.c

@@ -29,6 +29,13 @@
 #include <linux/unistd.h>
 #include <linux/ipc.h>
 #include <linux/uaccess.h>
+#include <linux/string.h>
+#include <linux/thread_info.h>
+#include <linux/entry-common.h>
+
+#include <asm/ptrace.h>
+#include <asm/vtime.h>
+
 #include "entry.h"
 
 /*
@@ -100,3 +107,66 @@ SYSCALL_DEFINE0(ni_syscall)
 {
 	return -ENOSYS;
 }
+
+void do_syscall(struct pt_regs *regs)
+{
+	unsigned long nr;
+
+	nr = regs->int_code & 0xffff;
+	if (!nr) {
+		nr = regs->gprs[1] & 0xffff;
+		regs->int_code &= ~0xffffUL;
+		regs->int_code |= nr;
+	}
+
+	regs->gprs[2] = nr;
+
+	nr = syscall_enter_from_user_mode_work(regs, nr);
+
+	/*
+	 * In the s390 ptrace ABI, both the syscall number and the return value
+	 * use gpr2. However, userspace puts the syscall number either in the
+	 * svc instruction itself, or uses gpr1. To make at least skipping syscalls
+	 * work, the ptrace code sets PIF_SYSCALL_RET_SET, which is checked here
+	 * and if set, the syscall will be skipped.
+	 */
+	if (!test_pt_regs_flag(regs, PIF_SYSCALL_RET_SET)) {
+		regs->gprs[2] = -ENOSYS;
+		if (likely(nr < NR_syscalls)) {
+			regs->gprs[2] = current->thread.sys_call_table[nr](
+					regs->orig_gpr2, regs->gprs[3],
+					regs->gprs[4], regs->gprs[5],
+					regs->gprs[6], regs->gprs[7]);
+		}
+	} else {
+		clear_pt_regs_flag(regs, PIF_SYSCALL_RET_SET);
+	}
+	syscall_exit_to_user_mode_work(regs);
+}
+
+void noinstr __do_syscall(struct pt_regs *regs, int per_trap)
+{
+	enter_from_user_mode(regs);
+
+	memcpy(&regs->gprs[8], S390_lowcore.save_area_sync, 8 * sizeof(unsigned long));
+	memcpy(&regs->int_code, &S390_lowcore.svc_ilc, sizeof(regs->int_code));
+	regs->psw = S390_lowcore.svc_old_psw;
+
+	update_timer_sys();
+
+	local_irq_enable();
+	regs->orig_gpr2 = regs->gprs[2];
+
+	if (per_trap)
+		set_thread_flag(TIF_PER_TRAP);
+
+	for (;;) {
+		regs->flags = 0;
+		set_pt_regs_flag(regs, PIF_SYSCALL);
+		do_syscall(regs);
+		if (!test_pt_regs_flag(regs, PIF_SYSCALL_RESTART))
+			break;
+		local_irq_enable();
+	}
+	exit_to_user_mode();
+}

arch/s390/kernel/traps.c

@@ -13,6 +13,8 @@
  * 'Traps.c' handles hardware traps and faults after we have saved some
  * state in 'asm.s'.
  */
+#include "asm/irqflags.h"
+#include "asm/ptrace.h"
 #include <linux/kprobes.h>
 #include <linux/kdebug.h>
 #include <linux/extable.h>
@@ -23,7 +25,9 @@
 #include <linux/slab.h>
 #include <linux/uaccess.h>
 #include <linux/cpu.h>
+#include <linux/entry-common.h>
 #include <asm/fpu/api.h>
+#include <asm/vtime.h>
 #include "entry.h"
 
 static inline void __user *get_trap_ip(struct pt_regs *regs)
@@ -288,3 +292,64 @@ void __init trap_init(void)
 	local_mcck_enable();
 	test_monitor_call();
 }
+
+void noinstr __do_pgm_check(struct pt_regs *regs)
+{
+	unsigned long last_break = S390_lowcore.breaking_event_addr;
+	unsigned int trapnr, syscall_redirect = 0;
+	irqentry_state_t state;
+
+	regs->int_code = *(u32 *)&S390_lowcore.pgm_ilc;
+	regs->int_parm_long = S390_lowcore.trans_exc_code;
+
+	state = irqentry_enter(regs);
+
+	if (user_mode(regs)) {
+		update_timer_sys();
+		if (last_break < 4096)
+			last_break = 1;
+		current->thread.last_break = last_break;
+		regs->args[0] = last_break;
+	}
+
+	if (S390_lowcore.pgm_code & 0x0200) {
+		/* transaction abort */
+		memcpy(&current->thread.trap_tdb, &S390_lowcore.pgm_tdb, 256);
+	}
+
+	if (S390_lowcore.pgm_code & PGM_INT_CODE_PER) {
+		if (user_mode(regs)) {
+			struct per_event *ev = &current->thread.per_event;
+
+			set_thread_flag(TIF_PER_TRAP);
+			ev->address = S390_lowcore.per_address;
+			ev->cause = *(u16 *)&S390_lowcore.per_code;
+			ev->paid = S390_lowcore.per_access_id;
+		} else {
+			/* PER event in kernel is kprobes */
+			__arch_local_irq_ssm(regs->psw.mask & ~PSW_MASK_PER);
+			do_per_trap(regs);
+			goto out;
+		}
+	}
+
+	if (!irqs_disabled_flags(regs->psw.mask))
+		trace_hardirqs_on();
+	__arch_local_irq_ssm(regs->psw.mask & ~PSW_MASK_PER);
+
+	trapnr = regs->int_code & PGM_INT_CODE_MASK;
+	if (trapnr)
+		pgm_check_table[trapnr](regs);
+	syscall_redirect = user_mode(regs) && test_pt_regs_flag(regs, PIF_SYSCALL);
+out:
+	local_irq_disable();
+	irqentry_exit(regs, state);
+
+	if (syscall_redirect) {
+		enter_from_user_mode(regs);
+		local_irq_enable();
+		regs->orig_gpr2 = regs->gprs[2];
+		do_syscall(regs);
+		exit_to_user_mode();
+	}
+}

arch/s390/kernel/uprobes.c

@@ -32,7 +32,7 @@ int arch_uprobe_pre_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)
 		return -EINVAL;
 	if (!is_compat_task() && psw_bits(regs->psw).eaba == PSW_BITS_AMODE_31BIT)
 		return -EINVAL;
-	clear_pt_regs_flag(regs, PIF_PER_TRAP);
+	clear_thread_flag(TIF_PER_TRAP);
 	auprobe->saved_per = psw_bits(regs->psw).per;
 	auprobe->saved_int_code = regs->int_code;
 	regs->int_code = UPROBE_TRAP_NR;
@@ -103,7 +103,7 @@ int arch_uprobe_post_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)
 		/* fix per address */
 		current->thread.per_event.address = utask->vaddr;
 		/* trigger per event */
-		set_pt_regs_flag(regs, PIF_PER_TRAP);
+		set_thread_flag(TIF_PER_TRAP);
 	}
 	return 0;
 }
@@ -259,7 +259,7 @@ static void sim_stor_event(struct pt_regs *regs, void *addr, int len)
 		return;
 	current->thread.per_event.address = regs->psw.addr;
 	current->thread.per_event.cause = PER_EVENT_STORE >> 16;
-	set_pt_regs_flag(regs, PIF_PER_TRAP);
+	set_thread_flag(TIF_PER_TRAP);
 }
 
 /*

arch/s390/kvm/kvm-s390.c

@@ -45,6 +45,7 @@
 #include <asm/timex.h>
 #include <asm/ap.h>
 #include <asm/uv.h>
+#include <asm/fpu/api.h>
 #include "kvm-s390.h"
 #include "gaccess.h"
 
@@ -4147,6 +4148,8 @@ static int __vcpu_run(struct kvm_vcpu *vcpu)
 			       vcpu->run->s.regs.gprs,
 			       sizeof(sie_page->pv_grregs));
 		}
+		if (test_cpu_flag(CIF_FPU))
+			load_fpu_regs();
 		exit_reason = sie64a(vcpu->arch.sie_block,
 				     vcpu->run->s.regs.gprs);
 		if (kvm_s390_pv_cpu_is_protected(vcpu)) {

arch/s390/kvm/vsie.c

@@ -18,6 +18,7 @@
 #include <asm/sclp.h>
 #include <asm/nmi.h>
 #include <asm/dis.h>
+#include <asm/fpu/api.h>
 #include "kvm-s390.h"
 #include "gaccess.h"
 
@@ -1028,6 +1029,8 @@ static int do_vsie_run(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
 	 */
 	vcpu->arch.sie_block->prog0c |= PROG_IN_SIE;
 	barrier();
+	if (test_cpu_flag(CIF_FPU))
+		load_fpu_regs();
 	if (!kvm_s390_vcpu_sie_inhibited(vcpu))
 		rc = sie64a(scb_s, vcpu->run->s.regs.gprs);
 	barrier();

arch/s390/lib/uaccess.c

@@ -16,8 +16,8 @@
 #include <asm/mmu_context.h>
 #include <asm/facility.h>
 
-#ifdef CONFIG_DEBUG_USER_ASCE
-void debug_user_asce(void)
+#ifdef CONFIG_DEBUG_ENTRY
+void debug_user_asce(int exit)
 {
 	unsigned long cr1, cr7;
 
@@ -25,12 +25,14 @@ void debug_user_asce(void)
 	__ctl_store(cr7, 7, 7);
 	if (cr1 == S390_lowcore.kernel_asce && cr7 == S390_lowcore.user_asce)
 		return;
-	panic("incorrect ASCE on kernel exit\n"
+	panic("incorrect ASCE on kernel %s\n"
 	      "cr1:    %016lx cr7:  %016lx\n"
 	      "kernel: %016llx user: %016llx\n",
-	      cr1, cr7, S390_lowcore.kernel_asce, S390_lowcore.user_asce);
+	      exit ? "exit" : "entry", cr1, cr7,
+	      S390_lowcore.kernel_asce, S390_lowcore.user_asce);
+
 }
-#endif /*CONFIG_DEBUG_USER_ASCE */
+#endif /*CONFIG_DEBUG_ENTRY */
 
 #ifndef CONFIG_HAVE_MARCH_Z10_FEATURES
 static DEFINE_STATIC_KEY_FALSE(have_mvcos);

arch/s390/mm/fault.c

@@ -385,7 +385,7 @@ static inline vm_fault_t do_exception(struct pt_regs *regs, int access)
 	 * The instruction that caused the program check has
 	 * been nullified. Don't signal single step via SIGTRAP.
 	 */
-	clear_pt_regs_flag(regs, PIF_PER_TRAP);
+	clear_thread_flag(TIF_PER_TRAP);
 
 	if (kprobe_page_fault(regs, 14))
 		return 0;