linux.git/arch/s390/kernel, branch v5.14

s390/vdso: add .got.plt in vdso linker script

2021-07-30T15:08:21+00:00

KCFLAGS="-mno-pic-data-is-text-relative" make leads to bfd assertion
error in s390_got_pointer():

LD      arch/s390/kernel/vdso64/vdso64.so.dbg
ld: BFD version 2.35-18.fc33 assertion fail elf-s390-common.c:74

readelf -Wr vdso64_generic.o | grep GOT
0000000000000032  000000110000001a R_390_GOTENT 0000000000000000 _vdso_data + 2
(...)

Add .got.plt in linker script to avoid this.

Suggested-by: Ilya Leoshkevich 
Signed-off-by: Sumanth Korikkar 
Signed-off-by: Heiko Carstens

Merge tag 's390-5.14-3' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux

2021-07-21T20:51:26+00:00

Pull s390 updates from Heiko Carstens:

 - fix / add expoline usage in "DMA" code

 - fix compat vdso Makefile to avoid permanent rebuild

 - fix ftrace_update_ftrace_func to avoid NULL pointer dereference

 - update defconfigs

 - trivial coding style fix

* tag 's390-5.14-3' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux:
  s390: update defconfigs
  s390/cpumf: fix semicolon.cocci warnings
  s390/boot: fix use of expolines in the DMA code
  s390/ftrace: fix ftrace_update_ftrace_func implementation
  s390/defconfig: allow early device mapper disks
  s390/vdso32: add vdso32.lds to targets

s390/cpumf: fix semicolon.cocci warnings

2021-07-20T15:59:40+00:00

arch/s390/kernel/perf_cpum_cf.c:748:2-3: Unneeded semicolon

 Remove unneeded semicolon.

Generated by: scripts/coccinelle/misc/semicolon.cocci

Fixes: a029a4eab39e ("s390/cpumf: Allow concurrent access for CPU Measurement Counter Facility")
CC: Thomas Richter 
Reported-by: kernel test robot 
Signed-off-by: kernel test robot 
Signed-off-by: Heiko Carstens

s390/ftrace: fix ftrace_update_ftrace_func implementation

2021-07-15T10:54:58+00:00

s390 enforces DYNAMIC_FTRACE if FUNCTION_TRACER is selected.
At the same time implementation of ftrace_caller is not compliant with
HAVE_DYNAMIC_FTRACE since it doesn't provide implementation of
ftrace_update_ftrace_func() and calls ftrace_trace_function() directly.

The subtle difference is that during ftrace code patching ftrace
replaces function tracer via ftrace_update_ftrace_func() and activates
it back afterwards. Unexpected direct calls to ftrace_trace_function()
during ftrace code patching leads to nullptr-dereferences when tracing
is activated for one of functions which are used during code patching.
Those function currently are:
copy_from_kernel_nofault()
copy_from_kernel_nofault_allowed()
preempt_count_sub() [with debug_defconfig]
preempt_count_add() [with debug_defconfig]

Corresponding KASAN report:
 BUG: KASAN: nullptr-dereference in function_trace_call+0x316/0x3b0
 Read of size 4 at addr 0000000000001e08 by task migration/0/15

 CPU: 0 PID: 15 Comm: migration/0 Tainted: G B 5.13.0-41423-g08316af3644d
 Hardware name: IBM 3906 M04 704 (LPAR)
 Stopper: multi_cpu_stop+0x0/0x3e0 <- stop_machine_cpuslocked+0x1e4/0x218
 Call Trace:
  [<0000000001f77caa>] show_stack+0x16a/0x1d0
  [<0000000001f8de42>] dump_stack+0x15a/0x1b0
  [<0000000001f81d56>] print_address_description.constprop.0+0x66/0x2e0
  [<000000000082b0ca>] kasan_report+0x152/0x1c0
  [<00000000004cfd8e>] function_trace_call+0x316/0x3b0
  [<0000000001fb7082>] ftrace_caller+0x7a/0x7e
  [<00000000006bb3e6>] copy_from_kernel_nofault_allowed+0x6/0x10
  [<00000000006bb42e>] copy_from_kernel_nofault+0x3e/0xd0
  [<000000000014605c>] ftrace_make_call+0xb4/0x1f8
  [<000000000047a1b4>] ftrace_replace_code+0x134/0x1d8
  [<000000000047a6e0>] ftrace_modify_all_code+0x120/0x1d0
  [<000000000047a7ec>] __ftrace_modify_code+0x5c/0x78
  [<000000000042395c>] multi_cpu_stop+0x224/0x3e0
  [<0000000000423212>] cpu_stopper_thread+0x33a/0x5a0
  [<0000000000243ff2>] smpboot_thread_fn+0x302/0x708
  [<00000000002329ea>] kthread+0x342/0x408
  [<00000000001066b2>] __ret_from_fork+0x92/0xf0
  [<0000000001fb57fa>] ret_from_fork+0xa/0x30

 The buggy address belongs to the page:
 page:(____ptrval____) refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1
 flags: 0x1ffff00000001000(reserved|node=0|zone=0|lastcpupid=0x1ffff)
 raw: 1ffff00000001000 0000040000000048 0000040000000048 0000000000000000
 raw: 0000000000000000 0000000000000000 ffffffff00000001 0000000000000000
 page dumped because: kasan: bad access detected

 Memory state around the buggy address:
  0000000000001d00: f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7
  0000000000001d80: f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7
 >0000000000001e00: f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7
                       ^
  0000000000001e80: f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7
  0000000000001f00: f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7
 ==================================================================

To fix that introduce ftrace_func callback to be called from
ftrace_caller and update it in ftrace_update_ftrace_func().

Fixes: 4cc9bed034d1 ("[S390] cleanup ftrace backend functions")
Cc: stable@vger.kernel.org
Reviewed-by: Heiko Carstens 
Signed-off-by: Vasily Gorbik 
Signed-off-by: Heiko Carstens

s390: Fix fall-through warnings for Clang

2021-07-13T19:43:09+00:00

Fix the following fallthrough warnings:

drivers/s390/net/ctcm_fsms.c:1457:2: warning: unannotated fall-through between switch labels [-Wimplicit-fallthrough]
drivers/s390/net/qeth_l3_main.c:437:3: warning: unannotated fall-through between switch labels [-Wimplicit-fallthrough]
drivers/s390/char/tape_char.c:374:4: warning: unannotated fall-through between switch labels [-Wimplicit-fallthrough]
arch/s390/kernel/uprobes.c:129:2: warning: unannotated fall-through between switch labels [-Wimplicit-fallthrough]

Reported-by: Nathan Chancellor 
Signed-off-by: Gustavo A. R. Silva

s390/vdso32: add vdso32.lds to targets

2021-07-12T12:33:53+00:00

This fixes a permanent rebuild of the 32 bit vdso. The RPM build process
was first calling 'make bzImage' and 'make modules' as a second step.
This caused a recompilation of vdso32.so, which in turn also changed
the build-id of vmlinux.

Fixes: 779df2248739 ("s390/vdso: add minimal compat vdso")
Signed-off-by: Sven Schnelle 
Reviewed-by: Alexander Gordeev 
Signed-off-by: Heiko Carstens

Merge tag 's390-5.14-2' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux

2021-07-10T17:46:14+00:00

Pull more s390 updates from Vasily Gorbik:

 - Fix preempt_count initialization.

 - Rework call_on_stack() macro to add proper type handling and avoid
   possible register corruption.

 - More error prone "register asm" removal and fixes.

 - Fix syscall restarting when multiple signals are coming in. This adds
   minimalistic trampolines to vdso so we can return from signal without
   using the stack which requires pgm check handler hacks when NX is
   enabled.

 - Remove HAVE_IRQ_EXIT_ON_IRQ_STACK since this is no longer true after
   switch to generic entry.

 - Fix protected virtualization secure storage access exception
   handling.

 - Make machine check C handler always enter with DAT enabled and move
   register validation to C code.

 - Fix tinyconfig boot problem by avoiding MONITOR CALL without
   CONFIG_BUG.

 - Increase asm symbols alignment to 16 to make it consistent with
   compilers.

 - Enable concurrent access to the CPU Measurement Counter Facility.

 - Add support for dynamic AP bus size limit and rework ap_dqap to deal
   with messages greater than recv buffer.

* tag 's390-5.14-2' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: (41 commits)
  s390: preempt: Fix preempt_count initialization
  s390/linkage: increase asm symbols alignment to 16
  s390: rename CALL_ON_STACK_NORETURN() to call_on_stack_noreturn()
  s390: add type checking to CALL_ON_STACK_NORETURN() macro
  s390: remove old CALL_ON_STACK() macro
  s390/softirq: use call_on_stack() macro
  s390/lib: use call_on_stack() macro
  s390/smp: use call_on_stack() macro
  s390/kexec: use call_on_stack() macro
  s390/irq: use call_on_stack() macro
  s390/mm: use call_on_stack() macro
  s390: introduce proper type handling call_on_stack() macro
  s390/irq: simplify on_async_stack()
  s390/irq: inline do_softirq_own_stack()
  s390/irq: simplify do_softirq_own_stack()
  s390/ap: get rid of register asm in ap_dqap()
  s390: rename PIF_SYSCALL_RESTART to PIF_EXECVE_PGSTE_RESTART
  s390: move restart of execve() syscall
  s390/signal: remove sigreturn on stack
  s390/signal: switch to using vdso for sigreturn and syscall restart
  ...

s390: preempt: Fix preempt_count initialization

2021-07-08T20:12:18+00:00

S390's init_idle_preempt_count(p, cpu) doesn't actually let us initialize the
preempt_count of the requested CPU's idle task: it unconditionally writes
to the current CPU's. This clearly conflicts with idle_threads_init(),
which intends to initialize *all* the idle tasks, including their
preempt_count (or their CPU's, if the arch uses a per-CPU preempt_count).

Unfortunately, it seems the way s390 does things doesn't let us initialize
every possible CPU's preempt_count early on, as the pages where this
resides are only allocated when a CPU is brought up and are freed when it
is brought down.

Let the arch-specific code set a CPU's preempt_count when its lowcore is
allocated, and turn init_idle_preempt_count() into an empty stub.

Fixes: f1a0a376ca0c ("sched/core: Initialize the idle task with preemption disabled")
Reported-by: Guenter Roeck 
Signed-off-by: Valentin Schneider 
Tested-by: Guenter Roeck 
Reviewed-by: Heiko Carstens 
Link: https://lore.kernel.org/r/20210707163338.1623014-1-valentin.schneider@arm.com
Signed-off-by: Vasily Gorbik

s390: rename CALL_ON_STACK_NORETURN() to call_on_stack_noreturn()

2021-07-08T20:12:18+00:00

Lower case matches the call_on_stack() macro and is easier to read.

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

s390/smp: use call_on_stack() macro

2021-07-08T20:12:18+00:00

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