linux.git/arch/s390/kernel/entry.h, branch v5.12

s390: convert to generic entry

2021-01-19T11:29:26+00:00

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 
Signed-off-by: Vasily Gorbik

s390/mm: remove set_fs / rework address space handling

2020-11-23T11:01:12+00:00

Remove set_fs support from s390. With doing this rework address space
handling and simplify it. As a result address spaces are now setup
like this:

CPU running in              | %cr1 ASCE | %cr7 ASCE | %cr13 ASCE
----------------------------|-----------|-----------|-----------
user space                  |  user     |  user     |  kernel
kernel, normal execution    |  kernel   |  user     |  kernel
kernel, kvm guest execution |  gmap     |  user     |  kernel

To achieve this the getcpu vdso syscall is removed in order to avoid
secondary address mode and a separate vdso address space in for user
space. The getcpu vdso syscall will be implemented differently with a
subsequent patch.

The kernel accesses user space always via secondary address space.
This happens in different ways:
- with mvcos in home space mode and directly read/write to secondary
  address space
- with mvcs/mvcp in primary space mode and copy from primary space to
  secondary space or vice versa
- with e.g. cs in secondary space mode and access secondary space

Switching translation modes happens with sacf before and after
instructions which access user space, like before.

Lazy handling of control register reloading is removed in the hope to
make everything simpler, but at the cost of making kernel entry and
exit a bit slower. That is: on kernel entry the primary asce is always
changed to contain the kernel asce, and on kernel exit the primary
asce is changed again so it contains the user asce.

In kernel mode there is only one exception to the primary asce: when
kvm guests are executed the primary asce contains the gmap asce (which
describes the guest address space). The primary asce is reset to
kernel asce whenever kvm guest execution is interrupted, so that this
doesn't has to be taken into account for any user space accesses.

Reviewed-by: Sven Schnelle 
Signed-off-by: Heiko Carstens

Merge tag 's390-5.10-1' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux

2020-10-16T19:36:38+00:00

Pull s390 updates from Vasily Gorbik:

 - Remove address space overrides using set_fs()

 - Convert to generic vDSO

 - Convert to generic page table dumper

 - Add ARCH_HAS_DEBUG_WX support

 - Add leap seconds handling support

 - Add NVMe firmware-assisted kernel dump support

 - Extend NVMe boot support with memory clearing control and addition of
   kernel parameters

 - AP bus and zcrypt api code rework. Add adapter configure/deconfigure
   interface. Extend debug features. Add failure injection support

 - Add ECC secure private keys support

 - Add KASan support for running protected virtualization host with
   4-level paging

 - Utilize destroy page ultravisor call to speed up secure guests
   shutdown

 - Implement ioremap_wc() and ioremap_prot() with MIO in PCI code

 - Various checksum improvements

 - Other small various fixes and improvements all over the code

* tag 's390-5.10-1' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: (85 commits)
  s390/uaccess: fix indentation
  s390/uaccess: add default cases for __put_user_fn()/__get_user_fn()
  s390/zcrypt: fix wrong format specifications
  s390/kprobes: move insn_page to text segment
  s390/sie: fix typo in SIGP code description
  s390/lib: fix kernel doc for memcmp()
  s390/zcrypt: Introduce Failure Injection feature
  s390/zcrypt: move ap_msg param one level up the call chain
  s390/ap/zcrypt: revisit ap and zcrypt error handling
  s390/ap: Support AP card SCLP config and deconfig operations
  s390/sclp: Add support for SCLP AP adapter config/deconfig
  s390/ap: add card/queue deconfig state
  s390/ap: add error response code field for ap queue devices
  s390/ap: split ap queue state machine state from device state
  s390/zcrypt: New config switch CONFIG_ZCRYPT_DEBUG
  s390/zcrypt: introduce msg tracking in zcrypt functions
  s390/startup: correct early pgm check info formatting
  s390: remove orphaned extern variables declarations
  s390/kasan: make sure int handler always run with DAT on
  s390/ipl: add support to control memory clearing for nvme re-IPL
  ...

s390/kprobes: move insn_page to text segment

2020-10-09T21:45:30+00:00

Move the in-kernel kprobes insn page to text segment. Rationale:
having that page in rw data segment is suboptimal, since as soon as a
kprobe is set, this will split the 1:1 kernel mapping for a single
page which get new permissions.

Note: there is always at least one kprobe present for the kretprobe
trampoline; so the mapping will always be split into smaller 4k
mappings because of this.

Moving the kprobes insn page into text segment makes sure that the
page is mapped RO/X in any case, and avoids that the 1:1 mapping is
split.

The kprobe insn_page is defined as a dummy function which is filled
with "br %r14" instructions.

Signed-off-by: Heiko Carstens 
Signed-off-by: Vasily Gorbik

s390: remove orphaned extern variables declarations

2020-10-02T12:40:48+00:00

arch/s390/kernel/entry.h: suspend_zero_pages - only declaration left
after commit 394216275c7d ("s390: remove broken hibernate / power
management support")

arch/s390/include/asm/setup.h: vmhalt_cmd - only declaration left after
commit 99ca4e582d4a ("[S390] kernel: Shutdown Actions Interface")

arch/s390/include/asm/setup.h: vmpoff_cmd - only declaration left after
commit 99ca4e582d4a ("[S390] kernel: Shutdown Actions Interface")

Signed-off-by: Vasily Gorbik

s390: remove orphaned function declarations

2020-09-30T10:09:54+00:00

arch/s390/pci/pci_bus.h: zpci_bus_init - only declaration left after
commit 05bc1be6db4b ("s390/pci: create zPCI bus")

arch/s390/include/asm/gmap.h: gmap_pte_notify - only declaration left
after commit 4be130a08420 ("s390/mm: add shadow gmap support")

arch/s390/include/asm/pgalloc.h: rcu_table_freelist_finish - only
declaration left after commit 36409f6353fc ("[S390] use generic RCU
page-table freeing code")

arch/s390/include/asm/tlbflush.h: smp_ptlb_all - only declaration left
after commit 5a79859ae0f3 ("s390: remove 31 bit support")

arch/s390/include/asm/vtimer.h: init_cpu_vtimer - only declaration left
after commit b5f87f15e200 ("s390/idle: consolidate idle functions and
definitions")

arch/s390/include/asm/pci.h: zpci_debug_info - only declaration left
after commit 386aa051fb4b ("s390/pci: remove per device debug attribute")

arch/s390/include/asm/vdso.h: vdso_alloc_boot_cpu - only declaration
left after commit 4bff8cb54502 ("s390: convert to GENERIC_VDSO")

arch/s390/include/asm/smp.h: smp_vcpu_scheduled - only declaration left
after commit 67626fadd269 ("s390: enforce CONFIG_SMP")

arch/s390/kernel/entry.h: restart_call_handler - only declaration left
after commit 8b646bd75908 ("[S390] rework smp code")

arch/s390/kernel/entry.h: startup_init_nobss - only declaration left
after commit 2e83e0eb85ca ("s390: clean .bss before running uncompressed
kernel")

arch/s390/kernel/entry.h: s390_early_resume - only declaration left after
commit 394216275c7d ("s390: remove broken hibernate / power management
support")

drivers/s390/char/raw3270.h: raw3270_request_alloc_bootmem - only
declaration left after commit 33403dcfcdfd ("[S390] 3270 console:
convert from bootmem to slab")

drivers/s390/cio/device.h: ccw_device_schedule_sch_unregister - only
declaration left after commit 37de53bb5290 ("[S390] cio: introduce ccw
device todos")

drivers/s390/char/tape.h: tape_hotplug_event - has only declaration
since recorded git history.

drivers/s390/char/tape.h: tape_oper_handler - has only declaration since
recorded git history.

drivers/s390/char/tape.h: tape_noper_handler - has only declaration
since recorded git history.

drivers/s390/char/tape_std.h: tape_std_check_locate - only declaration
left after commit 161beff8f40d ("s390/tape: remove tape block leftovers")

drivers/s390/char/tape_std.h: tape_std_default_handler - has only
declaration since recorded git history.

drivers/s390/char/tape_std.h: tape_std_unexpect_uchk_handler - has only
declaration since recorded git history.

drivers/s390/char/tape_std.h: tape_std_irq - has only declaration since
recorded git history.

drivers/s390/char/tape_std.h: tape_std_error_recovery - has only
declaration since recorded git history.

drivers/s390/char/tape_std.h: tape_std_error_recovery_has_failed -
has only declaration since recorded git history.

drivers/s390/char/tape_std.h: tape_std_error_recovery_succeded - has
only declaration since recorded git history.

drivers/s390/char/tape_std.h: tape_std_error_recovery_do_retry - has
only declaration since recorded git history.

drivers/s390/char/tape_std.h: tape_std_error_recovery_read_opposite -
has only declaration since recorded git history.

drivers/s390/char/tape_std.h: tape_std_error_recovery_HWBUG - has only
declaration since recorded git history.

Reviewed-by: Sven Schnelle 
Signed-off-by: Vasily Gorbik

s390: add 3f program exception handler

2020-09-14T08:08:07+00:00

Program exception 3f (secure storage violation) can only be detected
when the CPU is running in SIE with a format 4 state description,
e.g. running a protected guest. Because of this and because user
space partly controls the guest memory mapping and can trigger this
exception, we want to send a SIGSEGV to the process running the guest
and not panic the kernel.

Signed-off-by: Janosch Frank 
Cc:  # 5.7
Fixes: 084ea4d611a3 ("s390/mm: add (non)secure page access exceptions handlers")
Reviewed-by: Claudio Imbrenda 
Reviewed-by: Cornelia Huck 
Acked-by: Christian Borntraeger 
Signed-off-by: Heiko Carstens 
Signed-off-by: Vasily Gorbik

s390/mm: add (non)secure page access exceptions handlers

2020-02-27T18:44:40+00:00

Add exceptions handlers performing transparent transition of non-secure
pages to secure (import) upon guest access and secure pages to
non-secure (export) upon hypervisor access.

Signed-off-by: Vasily Gorbik 
[frankja@linux.ibm.com: adding checks for failures]
Signed-off-by: Janosch Frank 
[imbrenda@linux.ibm.com:  adding a check for gmap fault]
Signed-off-by: Claudio Imbrenda 
Acked-by: David Hildenbrand 
Acked-by: Cornelia Huck 
Reviewed-by: Christian Borntraeger 
[borntraeger@de.ibm.com: patch merging, splitting, fixing]
Signed-off-by: Christian Borntraeger

s390: fix __EMIT_BUG() macro

2020-01-22T12:05:35+00:00

Setting a kprobe on getname_flags() failed:

$ echo 'p:tmr1 getname_flags +0(%r2):ustring' > kprobe_events
-bash: echo: write error: Invalid argument

Debugging the kprobes code showed that the address of
getname_flags() is contained in the __bug_table. Kprobes
doesn't allow to set probes at BUG() locations.

$ objdump -j  __bug_table -x build/fs/namei.o
[..]
0000000000000108 R_390_PC32        .text+0x00000000000075a8
000000000000010c R_390_PC32        .L223+0x0000000000000004

I was expecting getname_flags() to start with a BUG(), but:

7598:       e3 20 10 00 00 04       lg      %r2,0(%r1)
759e:       c0 f4 00 00 00 00       jg      759e 
75a0: R_390_PLT32DBL    kmem_cache_free+0x2
75a4:       a7 f4 00 01             j       75a6 

00000000000075a8 :
75a8:       c0 04 00 00 00 00       brcl    0,75a8 
75ae:       eb 6f f0 48 00 24       stmg    %r6,%r15,72(%r15)
75b4:       b9 04 00 ef             lgr     %r14,%r15
75b8:       e3 f0 ff a8 ff 71       lay     %r15,-88(%r15)

So the BUG() is actually the last opcode of the previous function.
Fix this by switching to using the MONITOR CALL (MC) instruction,
and set the entry in __bug_table to the beginning of that MC.

Reviewed-by: Heiko Carstens 
Signed-off-by: Sven Schnelle 
Signed-off-by: Vasily Gorbik

PM: hibernate: powerpc: Expose pfn_is_nosave() prototype

2019-06-14T08:48:56+00:00

The declaration for pfn_is_nosave is only available in
kernel/power/power.h. Since this function can be override in arch,
expose it globally. Having a prototype will make sure to avoid warning
(sometime treated as error with W=1) such as:

  arch/powerpc/kernel/suspend.c:18:5: error: no previous prototype for 'pfn_is_nosave' [-Werror=missing-prototypes]

This moves the declaration into a globally visible header file and add
missing include to avoid a warning on powerpc.

Also remove the duplicated prototypes since not required anymore.

Signed-off-by: Mathieu Malaterre 
Acked-by: Michael Ellerman  (powerpc)
Signed-off-by: Rafael J. Wysocki