psw_t psw;
        unsigned long gprs[NUM_GPRS];
        unsigned long orig_gpr2;
-       unsigned short ilc;
-       unsigned short svcnr;
+       unsigned int svc_code;
 };
 
 /*
 #define PTRACE_POKETEXT_AREA         0x5004
 #define PTRACE_POKEDATA_AREA         0x5005
 #define PTRACE_GET_LAST_BREAK        0x5006
+#define PTRACE_PEEK_SYSTEM_CALL       0x5007
+#define PTRACE_POKE_SYSTEM_CALL              0x5008
 
 /*
  * PT_PROT definition is loosely based on hppa bsd definition in
 
 #define _ASM_SYSCALL_H 1
 
 #include <linux/sched.h>
+#include <linux/err.h>
 #include <asm/ptrace.h>
 
 /*
 static inline long syscall_get_nr(struct task_struct *task,
                                  struct pt_regs *regs)
 {
-       return regs->svcnr ? regs->svcnr : -1;
+       return regs->svc_code ? (regs->svc_code & 0xffff) : -1;
 }
 
 static inline void syscall_rollback(struct task_struct *task,
 static inline long syscall_get_error(struct task_struct *task,
                                     struct pt_regs *regs)
 {
-       return (regs->gprs[2] >= -4096UL) ? -regs->gprs[2] : 0;
+       return IS_ERR_VALUE(regs->gprs[2]) ? regs->gprs[2] : 0;
 }
 
 static inline long syscall_get_return_value(struct task_struct *task,
 
        unsigned int            cpu;            /* current CPU */
        int                     preempt_count;  /* 0 => preemptable, <0 => BUG */
        struct restart_block    restart_block;
+       unsigned int            system_call;
        __u64                   user_timer;
        __u64                   system_timer;
        unsigned long           last_break;     /* last breaking-event-address. */
 
        DEFINE(__PT_PSW, offsetof(struct pt_regs, psw));
        DEFINE(__PT_GPRS, offsetof(struct pt_regs, gprs));
        DEFINE(__PT_ORIG_GPR2, offsetof(struct pt_regs, orig_gpr2));
-       DEFINE(__PT_ILC, offsetof(struct pt_regs, ilc));
-       DEFINE(__PT_SVCNR, offsetof(struct pt_regs, svcnr));
+       DEFINE(__PT_SVC_CODE, offsetof(struct pt_regs, svc_code));
        DEFINE(__PT_SIZE, sizeof(struct pt_regs));
        BLANK();
        DEFINE(__SF_BACKCHAIN, offsetof(struct stack_frame, back_chain));
 
                return err;
 
        restore_fp_regs(¤t->thread.fp_regs);
-       regs->svcnr = 0;        /* disable syscall checks */
+       regs->svc_code = 0;     /* disable syscall checks */
        return 0;
 }
 
 
 SP_R14      =  STACK_FRAME_OVERHEAD + __PT_GPRS + 56
 SP_R15      =  STACK_FRAME_OVERHEAD + __PT_GPRS + 60
 SP_ORIG_R2   = STACK_FRAME_OVERHEAD + __PT_ORIG_GPR2
-SP_ILC      =  STACK_FRAME_OVERHEAD + __PT_ILC
-SP_SVCNR     = STACK_FRAME_OVERHEAD + __PT_SVCNR
+SP_SVC_CODE  = STACK_FRAME_OVERHEAD + __PT_SVC_CODE
 SP_SIZE      = STACK_FRAME_OVERHEAD + __PT_SIZE
 
 _TIF_WORK_SVC = (_TIF_SIGPENDING | _TIF_NOTIFY_RESUME | _TIF_NEED_RESCHED | \
        SAVE_ALL_SVC __LC_SVC_OLD_PSW,__LC_SAVE_AREA
        CREATE_STACK_FRAME __LC_SAVE_AREA
        mvc     SP_PSW(8,%r15),__LC_SVC_OLD_PSW
-       mvc     SP_ILC(4,%r15),__LC_SVC_ILC
+       mvc     SP_SVC_CODE(4,%r15),__LC_SVC_ILC
        l       %r12,__LC_THREAD_INFO   # load pointer to thread_info struct
 sysc_vtime:
        UPDATE_VTIME __LC_EXIT_TIMER,__LC_SYNC_ENTER_TIMER,__LC_USER_TIMER
        mvc     __LC_LAST_UPDATE_TIMER(8),__LC_SYNC_ENTER_TIMER
 sysc_do_svc:
        xr      %r7,%r7
-       icm     %r7,3,SP_SVCNR(%r15)    # load svc number and test for svc 0
+       icm     %r7,3,SP_SVC_CODE+2(%r15)# load svc number and test for svc 0
        bnz     BASED(sysc_nr_ok)       # svc number > 0
        # svc 0: system call number in %r1
        cl      %r1,BASED(.Lnr_syscalls)
        bnl     BASED(sysc_nr_ok)
-       sth     %r1,SP_SVCNR(%r15)
+       sth     %r1,SP_SVC_CODE+2(%r15)
        lr      %r7,%r1           # copy svc number to %r7
 sysc_nr_ok:
        sll     %r7,2             # svc number *4
 #
 sysc_restart:
        ni      __TI_flags+3(%r12),255-_TIF_RESTART_SVC # clear TIF_RESTART_SVC
-       l       %r7,SP_R2(%r15)         # load new svc number
-       mvc     SP_R2(4,%r15),SP_ORIG_R2(%r15) # restore first argument
        lm      %r2,%r6,SP_R2(%r15)     # load svc arguments
-       sth     %r7,SP_SVCNR(%r15)
+       xr      %r7,%r7                 # svc 0 returns -ENOSYS
+       clc     SP_SVC_CODE+2(%r15),BASED(.Lnr_syscalls+2)
+       bnl     BASED(sysc_nr_ok)       # invalid svc number -> do svc 0
+       icm     %r7,3,SP_SVC_CODE+2(%r15)# load new svc number
        b       BASED(sysc_nr_ok)       # restart svc
 
 #
 #
 sysc_singlestep:
        ni      __TI_flags+3(%r12),255-_TIF_PER_TRAP # clear TIF_PER_TRAP
-       xc      SP_SVCNR(2,%r15),SP_SVCNR(%r15)         # clear svc number
+       xc      SP_SVC_CODE(4,%r15),SP_SVC_CODE(%r15)   # clear svc code
        la      %r2,SP_PTREGS(%r15)     # address of register-save area
        l       %r1,BASED(.Lhandle_per) # load adr. of per handler
        la      %r14,BASED(sysc_return) # load adr. of system return
        la      %r2,SP_PTREGS(%r15)     # load pt_regs
        la      %r3,0
        xr      %r0,%r0
-       icm     %r0,3,SP_SVCNR(%r15)
+       icm     %r0,3,SP_SVC_CODE(%r15)
        st      %r0,SP_R2(%r15)
        basr    %r14,%r1
        cl      %r2,BASED(.Lnr_syscalls)
        bnz     BASED(pgm_per)          # got per exception -> special case
        SAVE_ALL_PGM __LC_PGM_OLD_PSW,__LC_SAVE_AREA
        CREATE_STACK_FRAME __LC_SAVE_AREA
-       xc      SP_ILC(4,%r15),SP_ILC(%r15)
+       xc      SP_SVC_CODE(4,%r15),SP_SVC_CODE(%r15)
        mvc     SP_PSW(8,%r15),__LC_PGM_OLD_PSW
        l       %r12,__LC_THREAD_INFO   # load pointer to thread_info struct
        tm      SP_PSW+1(%r15),0x01     # interrupting from user ?
        SAVE_ALL_PGM __LC_SVC_OLD_PSW,__LC_SAVE_AREA
        CREATE_STACK_FRAME __LC_SAVE_AREA
        mvc     SP_PSW(8,%r15),__LC_SVC_OLD_PSW
-       mvc     SP_ILC(4,%r15),__LC_SVC_ILC
+       mvc     SP_SVC_CODE(4,%r15),__LC_SVC_ILC
        l       %r12,__LC_THREAD_INFO   # load pointer to thread_info struct
        UPDATE_VTIME __LC_EXIT_TIMER,__LC_SYNC_ENTER_TIMER,__LC_USER_TIMER
        UPDATE_VTIME __LC_LAST_UPDATE_TIMER,__LC_EXIT_TIMER,__LC_SYSTEM_TIMER
 #
 kernel_per:
        REENABLE_IRQS
-       xc      SP_SVCNR(2,%r15),SP_SVCNR(%r15)
+       xc      SP_SVC_CODE(4,%r15),SP_SVC_CODE(%r15)
        la      %r2,SP_PTREGS(%r15)     # address of register-save area
        l       %r1,BASED(.Lhandle_per) # load adr. of per handler
        basr    %r14,%r1                # branch to do_single_step
        st      %r15,12(%r12)
        CREATE_STACK_FRAME __LC_SAVE_AREA
        mvc     SP_PSW(8,%r15),__LC_SVC_OLD_PSW
-       mvc     SP_ILC(4,%r15),__LC_SVC_ILC
+       mvc     SP_SVC_CODE(4,%r15),__LC_SVC_ILC
        mvc     0(4,%r12),__LC_THREAD_INFO
 cleanup_vtime:
        clc     __LC_RETURN_PSW+4(4),BASED(cleanup_system_call_insn+12)
 
 SP_R14      =  STACK_FRAME_OVERHEAD + __PT_GPRS + 112
 SP_R15      =  STACK_FRAME_OVERHEAD + __PT_GPRS + 120
 SP_ORIG_R2   = STACK_FRAME_OVERHEAD + __PT_ORIG_GPR2
-SP_ILC      =  STACK_FRAME_OVERHEAD + __PT_ILC
-SP_SVCNR      =        STACK_FRAME_OVERHEAD + __PT_SVCNR
+SP_SVC_CODE  = STACK_FRAME_OVERHEAD + __PT_SVC_CODE
 SP_SIZE      = STACK_FRAME_OVERHEAD + __PT_SIZE
 
 STACK_SHIFT = PAGE_SHIFT + THREAD_ORDER
        SAVE_ALL_SVC __LC_SVC_OLD_PSW,__LC_SAVE_AREA
        CREATE_STACK_FRAME __LC_SAVE_AREA
        mvc     SP_PSW(16,%r15),__LC_SVC_OLD_PSW
-       mvc     SP_ILC(4,%r15),__LC_SVC_ILC
+       mvc     SP_SVC_CODE(4,%r15),__LC_SVC_ILC
        lg      %r12,__LC_THREAD_INFO   # load pointer to thread_info struct
 sysc_vtime:
        UPDATE_VTIME __LC_EXIT_TIMER,__LC_SYNC_ENTER_TIMER,__LC_USER_TIMER
        mvc     __LC_LAST_UPDATE_TIMER(8),__LC_SYNC_ENTER_TIMER
        LAST_BREAK
 sysc_do_svc:
-       llgh    %r7,SP_SVCNR(%r15)
+       llgh    %r7,SP_SVC_CODE+2(%r15)
        slag    %r7,%r7,2       # shift and test for svc 0
        jnz     sysc_nr_ok
        # svc 0: system call number in %r1
        llgfr   %r1,%r1         # clear high word in r1
        cghi    %r1,NR_syscalls
        jnl     sysc_nr_ok
-       sth     %r1,SP_SVCNR(%r15)
+       sth     %r1,SP_SVC_CODE+2(%r15)
        slag    %r7,%r1,2       # shift and test for svc 0
 sysc_nr_ok:
        larl    %r10,sys_call_table
 #
 sysc_restart:
        ni      __TI_flags+7(%r12),255-_TIF_RESTART_SVC # clear TIF_RESTART_SVC
-       lg      %r7,SP_R2(%r15)         # load new svc number
-       mvc     SP_R2(8,%r15),SP_ORIG_R2(%r15) # restore first argument
        lmg     %r2,%r6,SP_R2(%r15)     # load svc arguments
-       sth     %r7,SP_SVCNR(%r15)
-       slag    %r7,%r7,2
+       lghi    %r7,0                   # svc 0 returns -ENOSYS
+       lh      %r1,SP_SVC_CODE+2(%r15) # load new svc number
+       cghi    %r1,NR_syscalls
+       jnl     sysc_nr_ok              # invalid svc number -> do svc 0
+       slag    %r7,%r1,2
        j       sysc_nr_ok              # restart svc
 
 #
 #
 sysc_singlestep:
        ni      __TI_flags+7(%r12),255-_TIF_PER_TRAP    # clear TIF_PER_TRAP
-       xc      SP_SVCNR(2,%r15),SP_SVCNR(%r15)         # clear svc number
+       xc      SP_SVC_CODE(4,%r15),SP_SVC_CODE(%r15)   # clear svc code
        la      %r2,SP_PTREGS(%r15)     # address of register-save area
        larl    %r14,sysc_return        # load adr. of system return
        jg      do_per_trap
 sysc_tracesys:
        la      %r2,SP_PTREGS(%r15)     # load pt_regs
        la      %r3,0
-       llgh    %r0,SP_SVCNR(%r15)
+       llgh    %r0,SP_SVC_CODE+2(%r15)
        stg     %r0,SP_R2(%r15)
        brasl   %r14,do_syscall_trace_enter
        lghi    %r0,NR_syscalls
        jnz     pgm_per                  # got per exception -> special case
        SAVE_ALL_PGM __LC_PGM_OLD_PSW,__LC_SAVE_AREA
        CREATE_STACK_FRAME __LC_SAVE_AREA
-       xc      SP_ILC(4,%r15),SP_ILC(%r15)
+       xc      SP_SVC_CODE(4,%r15),SP_SVC_CODE(%r15)
        mvc     SP_PSW(16,%r15),__LC_PGM_OLD_PSW
        lg      %r12,__LC_THREAD_INFO   # load pointer to thread_info struct
        HANDLE_SIE_INTERCEPT
        SAVE_ALL_PGM __LC_SVC_OLD_PSW,__LC_SAVE_AREA
        CREATE_STACK_FRAME __LC_SAVE_AREA
        mvc     SP_PSW(16,%r15),__LC_SVC_OLD_PSW
-       mvc     SP_ILC(4,%r15),__LC_SVC_ILC
+       mvc     SP_SVC_CODE(4,%r15),__LC_SVC_ILC
        lg      %r12,__LC_THREAD_INFO   # load pointer to thread_info struct
        UPDATE_VTIME __LC_EXIT_TIMER,__LC_SYNC_ENTER_TIMER,__LC_USER_TIMER
        UPDATE_VTIME __LC_LAST_UPDATE_TIMER,__LC_EXIT_TIMER,__LC_SYSTEM_TIMER
 #
 kernel_per:
        REENABLE_IRQS
-       xc      SP_SVCNR(2,%r15),SP_SVCNR(%r15) # clear svc number
+       xc      SP_SVC_CODE(4,%r15),SP_SVC_CODE(%r15)   # clear svc number
        la      %r2,SP_PTREGS(%r15)     # address of register-save area
        brasl   %r14,do_per_trap
        j       pgm_exit
        stg     %r11,0(%r12)
        CREATE_STACK_FRAME __LC_SAVE_AREA
        mvc     SP_PSW(16,%r15),__LC_SVC_OLD_PSW
-       mvc     SP_ILC(4,%r15),__LC_SVC_ILC
+       mvc     SP_SVC_CODE(4,%r15),__LC_SVC_ILC
        mvc     8(8,%r12),__LC_THREAD_INFO
 cleanup_vtime:
        clc     __LC_RETURN_PSW+8(8),BASED(cleanup_system_call_insn+24)
 
        REGSET_GENERAL,
        REGSET_FP,
        REGSET_LAST_BREAK,
+       REGSET_SYSTEM_CALL,
        REGSET_GENERAL_EXTENDED,
 };
 
                           high order bit but older gdb's rely on it */
                        data |= PSW_ADDR_AMODE;
 #endif
+               if (addr == (addr_t) &dummy->regs.psw.addr)
+                       /*
+                        * The debugger changed the instruction address,
+                        * reset system call restart, see signal.c:do_signal
+                        */
+                       task_thread_info(child)->system_call = 0;
+
                *(addr_t *)((addr_t) &task_pt_regs(child)->psw + addr) = data;
 
        } else if (addr < (addr_t) (&dummy->regs.orig_gpr2)) {
                        /* Build a 64 bit psw address from 31 bit address. */
                        task_pt_regs(child)->psw.addr =
                                (__u64) tmp & PSW32_ADDR_INSN;
+                       /*
+                        * The debugger changed the instruction address,
+                        * reset system call restart, see signal.c:do_signal
+                        */
+                       task_thread_info(child)->system_call = 0;
                } else {
                        /* gpr 0-15 */
                        *(__u32*)((addr_t) &task_pt_regs(child)->psw
                 * debugger stored an invalid system call number. Skip
                 * the system call and the system call restart handling.
                 */
-               regs->svcnr = 0;
+               regs->svc_code = 0;
                ret = -1;
        }
 
 
 #endif
 
+static int s390_system_call_get(struct task_struct *target,
+                               const struct user_regset *regset,
+                               unsigned int pos, unsigned int count,
+                               void *kbuf, void __user *ubuf)
+{
+       unsigned int *data = &task_thread_info(target)->system_call;
+       return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
+                                  data, 0, sizeof(unsigned int));
+}
+
+static int s390_system_call_set(struct task_struct *target,
+                               const struct user_regset *regset,
+                               unsigned int pos, unsigned int count,
+                               const void *kbuf, const void __user *ubuf)
+{
+       unsigned int *data = &task_thread_info(target)->system_call;
+       return user_regset_copyin(&pos, &count, &kbuf, &ubuf,
+                                 data, 0, sizeof(unsigned int));
+}
+
 static const struct user_regset s390_regsets[] = {
        [REGSET_GENERAL] = {
                .core_note_type = NT_PRSTATUS,
                .get = s390_last_break_get,
        },
 #endif
+       [REGSET_SYSTEM_CALL] = {
+               .core_note_type = NT_S390_SYSTEM_CALL,
+               .n = 1,
+               .size = sizeof(unsigned int),
+               .align = sizeof(unsigned int),
+               .get = s390_system_call_get,
+               .set = s390_system_call_set,
+       },
 };
 
 static const struct user_regset_view user_s390_view = {
                .align = sizeof(long),
                .get = s390_compat_last_break_get,
        },
+       [REGSET_SYSTEM_CALL] = {
+               .core_note_type = NT_S390_SYSTEM_CALL,
+               .n = 1,
+               .size = sizeof(compat_uint_t),
+               .align = sizeof(compat_uint_t),
+               .get = s390_system_call_get,
+               .set = s390_system_call_set,
+       },
        [REGSET_GENERAL_EXTENDED] = {
                .core_note_type = NT_S390_HIGH_GPRS,
                .n = sizeof(s390_compat_regs_high) / sizeof(compat_long_t),
 
 #include <asm/ucontext.h>
 #include <asm/uaccess.h>
 #include <asm/lowcore.h>
+#include <asm/compat.h>
 #include "entry.h"
 
 #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
        current->thread.fp_regs.fpc &= FPC_VALID_MASK;
 
        restore_fp_regs(¤t->thread.fp_regs);
-       regs->svcnr = 0;        /* disable syscall checks */
+       regs->svc_code = 0;     /* disable syscall checks */
        return 0;
 }
 
  */
 void do_signal(struct pt_regs *regs)
 {
-       unsigned long retval = 0, continue_addr = 0, restart_addr = 0;
        siginfo_t info;
        int signr;
        struct k_sigaction ka;
        else
                oldset = ¤t->blocked;
 
-       /* Are we from a system call? */
-       if (regs->svcnr) {
-               continue_addr = regs->psw.addr;
-               restart_addr = continue_addr - regs->ilc;
-               retval = regs->gprs[2];
-
-               /* Prepare for system call restart.  We do this here so that a
-                  debugger will see the already changed PSW. */
-               switch (retval) {
-               case -ERESTARTNOHAND:
-               case -ERESTARTSYS:
-               case -ERESTARTNOINTR:
-                       regs->gprs[2] = regs->orig_gpr2;
-                       regs->psw.addr = restart_addr;
-                       break;
-               case -ERESTART_RESTARTBLOCK:
-                       regs->gprs[2] = -EINTR;
-               }
-               regs->svcnr = 0;        /* Don't deal with this again. */
-       }
-
-       /* Get signal to deliver.  When running under ptrace, at this point
-          the debugger may change all our registers ... */
+       /*
+        * Get signal to deliver. When running under ptrace, at this point
+        * the debugger may change all our registers, including the system
+        * call information.
+        */
+       current_thread_info()->system_call = regs->svc_code;
        signr = get_signal_to_deliver(&info, &ka, regs, NULL);
-
-       /* Depending on the signal settings we may need to revert the
-          decision to restart the system call. */
-       if (signr > 0 && regs->psw.addr == restart_addr) {
-               if (retval == -ERESTARTNOHAND
-                   || (retval == -ERESTARTSYS
-                        && !(current->sighand->action[signr-1].sa.sa_flags
-                             & SA_RESTART))) {
-                       regs->gprs[2] = -EINTR;
-                       regs->psw.addr = continue_addr;
-               }
-       }
+       regs->svc_code = current_thread_info()->system_call;
 
        if (signr > 0) {
                /* Whee!  Actually deliver the signal.  */
-               int ret;
-#ifdef CONFIG_COMPAT
-               if (is_compat_task()) {
-                       ret = handle_signal32(signr, &ka, &info, oldset, regs);
-               }
-               else
-#endif
-                       ret = handle_signal(signr, &ka, &info, oldset, regs);
-               if (!ret) {
+               if (regs->svc_code > 0) {
+                       /* Check for system call restarting. */
+                       switch (regs->gprs[2]) {
+                       case -ERESTART_RESTARTBLOCK:
+                       case -ERESTARTNOHAND:
+                               regs->gprs[2] = -EINTR;
+                               break;
+                       case -ERESTARTSYS:
+                               if (!(ka.sa.sa_flags & SA_RESTART)) {
+                                       regs->gprs[2] = -EINTR;
+                                       break;
+                               }
+                       /* fallthrough */
+                       case -ERESTARTNOINTR:
+                               regs->gprs[2] = regs->orig_gpr2;
+                               regs->psw.addr = regs->psw.addr -
+                                       (regs->svc_code >> 16);
+                               break;
+                       }
+                       /* No longer in a system call */
+                       regs->svc_code = 0;
+               }
+
+               if ((is_compat_task() ?
+                    handle_signal32(signr, &ka, &info, oldset, regs) :
+                    handle_signal(signr, &ka, &info, oldset, regs)) == 0) {
                        /*
                         * A signal was successfully delivered; the saved
                         * sigmask will have been stored in the signal frame,
                         * Let tracing know that we've done the handler setup.
                         */
                        tracehook_signal_handler(signr, &info, &ka, regs,
-                                       test_thread_flag(TIF_SINGLE_STEP));
+                                        test_thread_flag(TIF_SINGLE_STEP));
                }
                return;
        }
 
+       /* No handlers present - check for system call restart */
+       if (regs->svc_code > 0) {
+               switch (regs->gprs[2]) {
+               case -ERESTART_RESTARTBLOCK:
+                       /* Restart with sys_restart_syscall */
+                       regs->svc_code = __NR_restart_syscall;
+               /* fallthrough */
+               case -ERESTARTNOHAND:
+               case -ERESTARTSYS:
+               case -ERESTARTNOINTR:
+                       /* Restart system call with magic TIF bit. */
+                       regs->gprs[2] = regs->orig_gpr2;
+                       set_thread_flag(TIF_RESTART_SVC);
+                       break;
+               }
+       }
+
        /*
         * If there's no signal to deliver, we just put the saved sigmask back.
         */
                clear_thread_flag(TIF_RESTORE_SIGMASK);
                sigprocmask(SIG_SETMASK, ¤t->saved_sigmask, NULL);
        }
-
-       /* Restart a different system call. */
-       if (retval == -ERESTART_RESTARTBLOCK
-           && regs->psw.addr == continue_addr) {
-               regs->gprs[2] = __NR_restart_syscall;
-               set_thread_flag(TIF_RESTART_SVC);
-       }
 }
 
 void do_notify_resume(struct pt_regs *regs)
 
 #define NT_S390_CTRS   0x304           /* s390 control registers */
 #define NT_S390_PREFIX 0x305           /* s390 prefix register */
 #define NT_S390_LAST_BREAK     0x306   /* s390 breaking event address */
+#define NT_S390_SYSTEM_CALL    0x307   /* s390 system call restart data */
 #define NT_ARM_VFP     0x400           /* ARM VFP/NEON registers */