Merge tag 's390-6.16-1' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux

Pull s390 updates from Heiko Carstens:

- Large rework of the protected key crypto code to allow for
asynchron

Merge tag 's390-6.16-1' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux

Pull s390 updates from Heiko Carstens:

- Large rework of the protected key crypto code to allow for
asynchronous handling without memory allocation

- Speed up system call entry/exit path by re-implementing lazy ASCE
handling

- Add module autoload support for the diag288_wdt watchdog device
driver

- Get rid of s390 specific strcpy() and strncpy() implementations, and
switch all remaining users to strscpy() when possible

- Various other small fixes and improvements

* tag 's390-6.16-1' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: (51 commits)
s390/pci: Serialize device addition and removal
s390/pci: Allow re-add of a reserved but not yet removed device
s390/pci: Prevent self deletion in disable_slot()
s390/pci: Remove redundant bus removal and disable from zpci_release_device()
s390/crypto: Extend protected key conversion retry loop
s390/pci: Fix __pcilg_mio_inuser() inline assembly
s390/ptrace: Always inline regs_get_kernel_stack_nth() and regs_get_register()
s390/thread_info: Cleanup header includes
s390/extmem: Add workaround for DCSS unload diag
s390/crypto: Rework protected key AES for true asynch support
s390/cpacf: Rework cpacf_pcc() to return condition code
s390/mm: Fix potential use-after-free in __crst_table_upgrade()
s390/mm: Add mmap_assert_write_locked() check to crst_table_upgrade()
s390/string: Remove strcpy() implementation
s390/con3270: Use strscpy() instead of strcpy()
s390/boot: Use strspcy() instead of strcpy()
s390: Simple strcpy() to strscpy() conversions
s390/pkey/crypto: Introduce xflags param for pkey in-kernel API
s390/pkey: Provide and pass xflags within pkey and zcrypt layers
s390/uv: Remove uv_get_secret_metadata function
...

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s390/mm: Reimplement lazy ASCE handling

Reduce system call overhead time (round trip time for invoking a
non-existent system call) by 25%.

With the removal of set_fs() [1] lazy control register han

s390/mm: Reimplement lazy ASCE handling

Reduce system call overhead time (round trip time for invoking a
non-existent system call) by 25%.

With the removal of set_fs() [1] lazy control register handling was removed
in order to keep kernel entry and exit simple. However this made system
calls slower.

With the conversion to generic entry [2] and numerous follow up changes
which simplified the entry code significantly, adding support for lazy asce
handling doesn't add much complexity to the entry code anymore.

In particular this means:

- On kernel entry the primary asce is not modified and contains the user
asce

- Kernel accesses which require secondary-space mode (for example futex
operations) are surrounded by enable_sacf_uaccess() and
disable_sacf_uaccess() calls. enable_sacf_uaccess() sets the primary asce
to kernel asce so that the sacf instruction can be used to switch to
secondary-space mode. The primary asce is changed back to user asce with
disable_sacf_uaccess().

The state of the control register which contains the primary asce is
reflected with a new TIF_ASCE_PRIMARY bit. This is required on context
switch so that the correct asce is restored for the scheduled in process.

In result address spaces are now setup like this:

CPU running in | %cr1 ASCE | %cr7 ASCE | %cr13 ASCE
-----------------------------|-----------|-----------|-----------
user space | user | user | kernel
kernel (no sacf) | user | user | kernel
kernel (during sacf uaccess) | kernel | user | kernel
kernel (kvm guest execution) | guest | user | kernel

In result cr1 control register content is not changed except for:
- futex system calls
- legacy s390 PCI system calls
- the kvm specific cmpxchg_user_key() uaccess helper

This leads to faster system call execution.

[1] 87d598634521 ("s390/mm: remove set_fs / rework address space handling")
[2] 56e62a737028 ("s390: convert to generic entry")

Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

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