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>

1 files changed, 5 insertions, 7 deletions

diff --git a/arch/s390/kernel/entry.h b/arch/s390/kernel/entry.h
index a16c33b32ab0..3d0c0ac5c20e 100644
--- a/arch/s390/kernel/entry.h
+++ b/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);