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, 0 insertions, 102 deletions

diff --git a/arch/s390/kernel/sys_s390.c b/arch/s390/kernel/sys_s390.c
deleted file mode 100644
index 202fa73ac167..000000000000
--- a/arch/s390/kernel/sys_s390.c
+++ /dev/null
@@ -1,102 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-/*
- *  S390 version
- *    Copyright IBM Corp. 1999, 2000
- *    Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com),
- *               Thomas Spatzier (tspat@de.ibm.com)
- *
- *  Derived from "arch/i386/kernel/sys_i386.c"
- *
- *  This file contains various random system calls that
- *  have a non-standard calling sequence on the Linux/s390
- *  platform.
- */
-
-#include <linux/errno.h>
-#include <linux/sched.h>
-#include <linux/mm.h>
-#include <linux/fs.h>
-#include <linux/smp.h>
-#include <linux/sem.h>
-#include <linux/msg.h>
-#include <linux/shm.h>
-#include <linux/stat.h>
-#include <linux/syscalls.h>
-#include <linux/mman.h>
-#include <linux/file.h>
-#include <linux/utsname.h>
-#include <linux/personality.h>
-#include <linux/unistd.h>
-#include <linux/ipc.h>
-#include <linux/uaccess.h>
-#include "entry.h"
-
-/*
- * Perform the mmap() system call. Linux for S/390 isn't able to handle more
- * than 5 system call parameters, so this system call uses a memory block
- * for parameter passing.
- */
-
-struct s390_mmap_arg_struct {
-	unsigned long addr;
-	unsigned long len;
-	unsigned long prot;
-	unsigned long flags;
-	unsigned long fd;
-	unsigned long offset;
-};
-
-SYSCALL_DEFINE1(mmap2, struct s390_mmap_arg_struct __user *, arg)
-{
-	struct s390_mmap_arg_struct a;
-	int error = -EFAULT;
-
-	if (copy_from_user(&a, arg, sizeof(a)))
-		goto out;
-	error = ksys_mmap_pgoff(a.addr, a.len, a.prot, a.flags, a.fd, a.offset);
-out:
-	return error;
-}
-
-#ifdef CONFIG_SYSVIPC
-/*
- * sys_ipc() is the de-multiplexer for the SysV IPC calls.
- */
-SYSCALL_DEFINE5(s390_ipc, uint, call, int, first, unsigned long, second,
-		unsigned long, third, void __user *, ptr)
-{
-	if (call >> 16)
-		return -EINVAL;
-	/* The s390 sys_ipc variant has only five parameters instead of six
-	 * like the generic variant. The only difference is the handling of
-	 * the SEMTIMEDOP subcall where on s390 the third parameter is used
-	 * as a pointer to a struct timespec where the generic variant uses
-	 * the fifth parameter.
-	 * Therefore we can call the generic variant by simply passing the
-	 * third parameter also as fifth parameter.
-	 */
-	return ksys_ipc(call, first, second, third, ptr, third);
-}
-#endif /* CONFIG_SYSVIPC */
-
-SYSCALL_DEFINE1(s390_personality, unsigned int, personality)
-{
-	unsigned int ret = current->personality;
-
-	if (personality(current->personality) == PER_LINUX32 &&
-	    personality(personality) == PER_LINUX)
-		personality |= PER_LINUX32;
-
-	if (personality != 0xffffffff)
-		set_personality(personality);
-
-	if (personality(ret) == PER_LINUX32)
-		ret &= ~PER_LINUX32;
-
-	return ret;
-}
-
-SYSCALL_DEFINE0(ni_syscall)
-{
-	return -ENOSYS;
-}