linux.git/arch/s390/kernel, branch v5.3.2

s390/vdso: map vdso also for statically linked binaries

2019-08-09T09:03:28+00:00

s390 does not map the vdso for statically linked binaries, assuming
that this doesn't make sense. See commit fc5243d98ac2 ("[S390]
arch_setup_additional_pages arguments").

However with glibc commit d665367f596d ("linux: Enable vDSO for static
linking as default (BZ#19767)") and commit 5e855c895401 ("s390: Enable
VDSO for static linking") the vdso is also used for statically linked
binaries - if the kernel would make it available.

Therefore map the vdso always, just like all other architectures.

Reported-by: Stefan Liebler 
Signed-off-by: Heiko Carstens 
Signed-off-by: Vasily Gorbik

s390: put _stext and _etext into .text section

2019-08-06T11:58:35+00:00

Perf relies on _etext and _stext symbols being one of 't', 'T', 'v' or
'V'. Put them into .text section to guarantee that.

Also moves padding to page boundary inside .text which has an effect that
.text section is now padded with nops rather than 0's, which apparently
has been the initial intention for specifying 0x0700 fill expression.

Reported-by: Thomas Richter 
Tested-by: Thomas Richter 
Suggested-by: Andreas Krebbel 
Signed-off-by: Vasily Gorbik

s390/head64: cleanup unused labels

2019-08-06T11:58:35+00:00

Cleanup labels in head64 some of which are not being used since git
recorded history.

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

s390/unwind: remove stack recursion warning

2019-08-06T11:58:35+00:00

Remove pointless stack recursion on stack type ... warning, which
only confuses people. There is no way to make backchain unwinder 100%
reliable. When a task is interrupted in-between stack frame allocation
and backchain write instructions new stack frame backchain pointer is
left uninitialized (there are also sometimes additional instruction
in-between stack frame allocation and backchain write instructions due
to gcc shrink-wrapping). In attempt to unwind such stack the unwinder
would still try to use that invalid backchain value and perform all kind
of sanity checks on it to make sure we are not pointed out of stack. In
some cases that invalid backchain value would be 0 and we would falsely
treat next stackframe as pt_regs and again gprs[15] in those pt_regs
might happen to point at some address within the task's stack.

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

s390/setup: adjust start_code of init_mm to _text

2019-08-06T11:58:34+00:00

After some investigation it doesn't look like init_mm fields
start_code/end_code are used anywhere besides potentially in dump_mm for
debugging purposes. Originally the value of 0 for start_code reflected
the presence of lowcore and early boot code. But with kaslr in place
start_code/end_code range should not span over unoccupied by the code
segment memory. So, adjust init_mm start_code to point at the beginning
of the code segment like other architectures do it.

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

s390/protvirt: avoid memory sharing for diag 308 set/store

2019-08-06T11:58:34+00:00

This reverts commit db9492cef45e ("s390/protvirt: add memory sharing for
diag 308 set/store") which due to ultravisor implementation change is
not needed after all.

Fixes: db9492cef45e ("s390/protvirt: add memory sharing for diag 308 set/store")
Reviewed-by: Janosch Frank 
Signed-off-by: Vasily Gorbik

s390/kexec: add missing include to machine_kexec_reloc.c

2019-07-29T16:05:03+00:00

Include  into machine_kexec_reloc.c to expose
arch_kexec_do_relocs declaration and avoid the following sparse warnings:
arch/s390/kernel/machine_kexec_reloc.c:4:5: warning: symbol 'arch_kexec_do_relocs' was not declared. Should it be static?
arch/s390/boot/../kernel/machine_kexec_reloc.c:4:5: warning: symbol 'arch_kexec_do_relocs' was not declared. Should it be static?

Signed-off-by: Vasily Gorbik

s390/perf: make cf_diag_csd static

2019-07-29T16:05:02+00:00

Since there is really no reason for cf_diag_csd per cpu variable to be
globally visible make it static to avoid the following sparse warning:
arch/s390/kernel/perf_cpum_cf_diag.c:37:1: warning: symbol 'cf_diag_csd' was not declared. Should it be static?

Signed-off-by: Vasily Gorbik

s390: wire up clone3 system call

2019-07-23T08:45:53+00:00

Tested (64-bit and compat mode) using program from
http://lkml.kernel.org/r/20190604212930.jaaztvkent32b7d3@brauner.io
with the following:
       return syscall(__NR_clone, flags, 0, pidfd, 0, 0);
changed to:
       return syscall(__NR_clone, 0, flags, pidfd, 0, 0);
due to CLONE_BACKWARDS2.

Signed-off-by: Vasily Gorbik 
Acked-by: Christian Borntraeger 
Signed-off-by: Heiko Carstens

proc/sysctl: add shared variables for range check

2019-07-19T00:08:07+00:00

In the sysctl code the proc_dointvec_minmax() function is often used to
validate the user supplied value between an allowed range.  This
function uses the extra1 and extra2 members from struct ctl_table as
minimum and maximum allowed value.

On sysctl handler declaration, in every source file there are some
readonly variables containing just an integer which address is assigned
to the extra1 and extra2 members, so the sysctl range is enforced.

The special values 0, 1 and INT_MAX are very often used as range
boundary, leading duplication of variables like zero=0, one=1,
int_max=INT_MAX in different source files:

    $ git grep -E '\.extra[12].*&(zero|one|int_max)' |wc -l
    248

Add a const int array containing the most commonly used values, some
macros to refer more easily to the correct array member, and use them
instead of creating a local one for every object file.

This is the bloat-o-meter output comparing the old and new binary
compiled with the default Fedora config:

    # scripts/bloat-o-meter -d vmlinux.o.old vmlinux.o
    add/remove: 2/2 grow/shrink: 0/2 up/down: 24/-188 (-164)
    Data                                         old     new   delta
    sysctl_vals                                    -      12     +12
    __kstrtab_sysctl_vals                          -      12     +12
    max                                           14      10      -4
    int_max                                       16       -     -16
    one                                           68       -     -68
    zero                                         128      28    -100
    Total: Before=20583249, After=20583085, chg -0.00%

[mcroce@redhat.com: tipc: remove two unused variables]
  Link: http://lkml.kernel.org/r/20190530091952.4108-1-mcroce@redhat.com
[akpm@linux-foundation.org: fix net/ipv6/sysctl_net_ipv6.c]
[arnd@arndb.de: proc/sysctl: make firmware loader table conditional]
  Link: http://lkml.kernel.org/r/20190617130014.1713870-1-arnd@arndb.de
[akpm@linux-foundation.org: fix fs/eventpoll.c]
Link: http://lkml.kernel.org/r/20190430180111.10688-1-mcroce@redhat.com
Signed-off-by: Matteo Croce 
Signed-off-by: Arnd Bergmann 
Acked-by: Kees Cook 
Reviewed-by: Aaron Tomlin 
Cc: Matthew Wilcox 
Cc: Stephen Rothwell 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds