If user space is running in primary mode it can switch to secondary
or access register mode, this is used e.g. in the clock_gettime code
of the vdso. If a signal is delivered to the user space process while
it has been running in access register mode the signal handler is
executed in access register mode as well which will result in a crash
most of the time.
Set the address space control bits in the PSW to the default for the
execution of the signal handler and make sure that the previous
address space control is restored on signal return. Take care
that user space can not switch to the kernel address space by
modifying the registers in the signal frame.
Cc: stable@vger.kernel.org
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
It turns out that S390 shouldn't use uapi/asm-generic/kvm_para.h since it
defines the functions in its non-UAPI kvm_para.h file.
#including <asm-generic/kvm_para.h> will first pick up
include/asm-generic/kvm_para.h, which defines conflicting functions.
Instead, partially revert commit 0420c87e64,
ungenericising this file and just inserting a comment to prevent the patch
program from deleting it.
cc: Yuanhan Liu <yuanhan.liu@intel.com>
cc: fengguang.wu@intel.com
Reported-by: Yuanhan Liu <yuanhan.liu@intel.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Add back a hunk from "4dcc2a4 s390/chsc: make headers usable"
which was lost during the merge of the UAPI patch.
Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Make uapi/asm-generic/kvm_para.h non-empty by addition of a comment to stop
the patch program from deleting it when it creates it.
Then delete empty arch-specific uapi/asm/kvm_para.h files and tell the Kbuild
files to use the generic instead.
Should this perhaps instead be a #warning or #error that the facility is
unsupported on this arch?
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Arnd Bergmann <arnd@arndb.de>
cc: Avi Kivity <avi@redhat.com>
cc: Marcelo Tosatti <mtosatti@redhat.com>
cc: kvm@vger.kernel.org
git://git.infradead.org/users/dhowells/linux-headers
Pull UAPI patchset from David Howells:
"Can you merge the following branch into the s390 tree please.
This is to complete part of the UAPI disintegration for which the
preparatory patches were pulled recently."
Conflicts:
arch/s390/include/asm/chpid.h
