linux/arch/s390
Sven Schnelle 56e62a7370 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>
2021-01-19 12:29:26 +01:00
..
appldata s390/appldata: use struct_size() helper 2020-06-29 16:32:34 +02:00
boot kasan, x86, s390: update undef CONFIG_KASAN 2020-12-22 12:55:08 -08:00
configs s390: convert to generic entry 2021-01-19 12:29:26 +01:00
crypto - Add support for the hugetlb_cma command line option to allocate gigantic 2020-12-14 16:22:26 -08:00
hypfs fs_parse: fold fs_parameter_desc/fs_parameter_spec 2020-02-07 14:48:37 -05:00
include s390: convert to generic entry 2021-01-19 12:29:26 +01:00
kernel s390: convert to generic entry 2021-01-19 12:29:26 +01:00
kvm s390: convert to generic entry 2021-01-19 12:29:26 +01:00
lib s390: convert to generic entry 2021-01-19 12:29:26 +01:00
mm s390: convert to generic entry 2021-01-19 12:29:26 +01:00
net s390/bpf: Fix multiple tail calls 2020-09-14 18:21:31 -07:00
oprofile s390/unwind: introduce stack unwind API 2019-05-02 13:54:11 +02:00
pci mm: simplify follow_pte{,pmd} 2020-12-15 22:46:19 -08:00
purgatory - Add support for the hugetlb_cma command line option to allocate gigantic 2020-12-14 16:22:26 -08:00
tools .gitignore: add SPDX License Identifier 2020-03-25 11:50:48 +01:00
Kbuild s390/numa: move code to arch/s390/kernel 2020-08-11 18:16:55 +02:00
Kconfig s390: convert to generic entry 2021-01-19 12:29:26 +01:00
Kconfig.debug s390: convert to generic entry 2021-01-19 12:29:26 +01:00
Makefile s390/decompressor: add stacktrace support 2020-11-20 19:19:11 +01:00