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git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux
Pull s390 updates from Vasily Gorbik:
- Remove restrictions on PAI NNPA and crypto counters, enabling
concurrent per-task and system-wide sampling and counting events
- Switch to GENERIC_CPU_DEVICES by setting up the CPU present mask in
the architecture code and letting the generic code handle CPU
bring-up
- Add support for the diag204 busy indication facility to prevent
undesirable blocking during hypervisor logical CPU utilization
queries. Implement results caching
- Improve the handling of Store Data SCLP events by suppressing
unnecessary warning, preventing buffer release in I/O during
failures, and adding timeout handling for Store Data requests to
address potential firmware issues
- Provide optimized __arch_hweight*() implementations
- Remove the unnecessary CPU KOBJ_CHANGE uevents generated during
topology updates, as they are unused and also not present on other
architectures
- Cleanup atomic_ops, optimize __atomic_set() for small values and
__atomic_cmpxchg_bool() for compilers supporting flag output
constraint
- Couple of cleanups for KVM:
- Move and improve KVM struct definitions for DAT tables from
gaccess.c to a new header
- Pass the asce as parameter to sie64a()
- Make the crdte() and cspg() page table handling wrappers return a
boolean to indicate success, like the other existing "compare and
swap" wrappers
- Add documentation for HWCAP flags
- Switch to obtaining total RAM pages from memblock instead of
totalram_pages() during mm init, to ensure correct calculation of
zero page size, when defer_init is enabled
- Refactor lowcore access and switch to using the get_lowcore()
function instead of the S390_lowcore macro
- Cleanups for PG_arch_1 and folio handling in UV and hugetlb code
- Add missing MODULE_DESCRIPTION() macros
- Fix VM_FAULT_HWPOISON handling in do_exception()
* tag 's390-6.11-1' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: (54 commits)
s390/mm: Fix VM_FAULT_HWPOISON handling in do_exception()
s390/kvm: Move bitfields for dat tables
s390/entry: Pass the asce as parameter to sie64a()
s390/sthyi: Use cached data when diag is busy
s390/sthyi: Move diag operations
s390/hypfs_diag: Diag204 busy loop
s390/diag: Add busy-indication-facility requirements
s390/diag: Diag204 add busy return errno
s390/diag: Return errno's from diag204
s390/sclp: Diag204 busy indication facility detection
s390/atomic_ops: Make use of flag output constraint
s390/atomic_ops: Improve __atomic_set() for small values
s390/atomic_ops: Use symbolic names
s390/smp: Switch to GENERIC_CPU_DEVICES
s390/hwcaps: Add documentation for HWCAP flags
s390/pgtable: Make crdte() and cspg() return a value
s390/topology: Remove CPU KOBJ_CHANGE uevents
s390/sclp: Add timeout to Store Data requests
s390/sclp: Prevent release of buffer in I/O
s390/sclp: Suppress unnecessary Store Data warning
...
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The mmap2() syscall has never been used on 64-bit s390x and should
have been removed as part of 5a79859ae0f3 ("s390: remove 31 bit
support").
Remove it now.
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
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Replace all S390_lowcore usages in arch/s390/ by get_lowcore().
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
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The Breaking-Event-Address-Register (BEAR) stores the address of the
last breaking event instruction. Breaking events are usually instructions
that change the program flow - for example branches, and instructions
that modify the address in the PSW like lpswe. This is useful for debugging
wild branches, because one could easily figure out where the wild branch
was originating from.
What is problematic is that lpswe is considered a breaking event, and
therefore overwrites BEAR on kernel exit. The BEAR enhancement facility
adds new instructions that allow to save/restore BEAR and also an lpswey
instruction that doesn't cause a breaking event. So we can save BEAR on
kernel entry and restore it on exit to user space.
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
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PIF_SYSCALL_RESTART is now only used to restart execve when loading
PGSTE binaries. Rename the flag to reflect that, and avoid people
thinking that this bit has anything to do with generic syscall
restarting.
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
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On s390, execve might have to be restarted for PGSTE binaries
like kvm. In the past this was done via the PIF_SYSCALL_RESTART
bit. However, with the recent changes, syscalls are now restarted
differently. Now that execve() is the only call that might get
restarted via PIF_SYSCALL_RESTART, move the loop to do_syscall().
This also has the advantage that the restart is no longer visible
to userspace.
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
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{rt_}sigreturn is now called from the vdso, so we no longer
need the svc on the stack, and therefore no hack to support that
mechanism on machines with non-executable stack.
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
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with generic entry, there's a bug when it comes to restarting of signals.
The failing sequence is:
a) a signal is coming in, and no handler is registered, so the lower
part of arch_do_signal_or_restart() in arch/s390/kernel/signal.c
sets PIF_SYSCALL_RESTART.
b) a second signal gets pending while the kernel is still in the exit
loop, and for that one, a handler exists.
c) The first part of arch_do_signal_or_restart() is called. That part
calls handle_signal(), which sets up stack + registers for handling
the signal.
d) __do_syscall() in arch/s390/kernel/syscall.c checks for
PIF_SYSCALL_RESTART right before leaving to userspace. If it is set,
it restart's the syscall. However, the registers are already setup
for handling a signal from c). The syscall is now restarted with the
wrong arguments.
Change the code to:
- use vdso for syscall_restart() instead of PIF_SYSCALL_RESTART because
we cannot rewind and go back to userspace on s390 because the system call
number might be encoded in the svc instruction.
- for all other syscalls we rewind the PSW and return to userspace.
Cc: <stable@kernel.org> # v5.12+ d57778feb987: s390/vdso: always enable vdso
Cc: <stable@kernel.org> # v5.12+ 686341f2548b: s390/vdso64: add sigreturn,rt_sigreturn and restart_syscall
Cc: <stable@kernel.org> # v5.12+ 43e1f76b0b69: s390/vdso: rename VDSO64_LBASE to VDSO_LBASE
Cc: <stable@kernel.org> # v5.12+ 779df2248739: s390/vdso: add minimal compat vdso
Cc: <stable@kernel.org> # v5.12+
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
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arch/s390/kernel/syscall.c: In function __do_syscall:
arch/s390/kernel/syscall.c:147:9: warning: memcpy reading 64 bytes from a region of size 0 [-Wstringop-overread]
147 | memcpy(®s->gprs[8], S390_lowcore.save_area_sync, 8 * sizeof(unsigned long));
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
arch/s390/kernel/syscall.c:148:9: warning: memcpy reading 4 bytes from a region of size 0 [-Wstringop-overread]
148 | memcpy(®s->int_code, &S390_lowcore.svc_ilc, sizeof(regs->int_code));
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Fix this by moving the gprs restore from C to assembly, and use a assignment
for int_code instead of memcpy.
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
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This adds support for adding a random offset to the stack while handling
syscalls. The patch uses get_tod_clock_fast() as this is considered good
enough and has much less performance penalty compared to using
get_random_int(). The patch also adds randomization in pgm_check_handler()
as the sigreturn/rt_sigreturn system calls might be called from there.
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Link: https://lore.kernel.org/r/20210429091451.1062594-1-svens@linux.ibm.com
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
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Instead of fetching all registers from struct pt_regs and passing
them to the syscall wrappers, let the system call wrappers only
fetch the values really required.
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
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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>
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