linux-toradex.git/arch/s390, branch v5.4

s390/idle: fix cpu idle time calculation

2019-10-31T16:26:48+00:00

The idle time reported in /proc/stat sometimes incorrectly contains
huge values on s390. This is caused by a bug in arch_cpu_idle_time().

The kernel tries to figure out when a different cpu entered idle by
accessing its per-cpu data structure. There is an ordering problem: if
the remote cpu has an idle_enter value which is not zero, and an
idle_exit value which is zero, it is assumed it is idle since
"now". The "now" timestamp however is taken before the idle_enter
value is read.

Which in turn means that "now" can be smaller than idle_enter of the
remote cpu. Unconditionally subtracting idle_enter from "now" can thus
lead to a negative value (aka large unsigned value).

Fix this by moving the get_tod_clock() invocation out of the
loop. While at it also make the code a bit more readable.

A similar bug also exists for show_idle_time(). Fix this is as well.

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

s390/unwind: fix mixing regs and sp

2019-10-31T16:26:48+00:00

unwind_for_each_frame stops after the first frame if regs->gprs[15] <=
sp.

The reason is that in case regs are specified, the first frame should be
regs->psw.addr and the second frame should be sp->gprs[8]. However,
currently the second frame is regs->gprs[15], which confuses
outside_of_stack().

Fix by introducing a flag to distinguish this special case from
unwinding the interrupt handler, for which the current behavior is
appropriate.

Fixes: 78c98f907413 ("s390/unwind: introduce stack unwind API")
Signed-off-by: Ilya Leoshkevich 
Cc: stable@vger.kernel.org # v5.2+
Reviewed-by: Heiko Carstens 
Signed-off-by: Vasily Gorbik

s390/cmm: fix information leak in cmm_timeout_handler()

2019-10-31T16:26:48+00:00

The problem is that we were putting the NUL terminator too far:

	buf[sizeof(buf) - 1] = '\0';

If the user input isn't NUL terminated and they haven't initialized the
whole buffer then it leads to an info leak.  The NUL terminator should
be:

	buf[len - 1] = '\0';

Signed-off-by: Yihui Zeng 
Cc: stable@vger.kernel.org
Signed-off-by: Dan Carpenter 
[heiko.carstens@de.ibm.com: keep semantics of how *lenp and *ppos are handled]
Signed-off-by: Heiko Carstens 
Signed-off-by: Vasily Gorbik

s390/kaslr: add support for R_390_GLOB_DAT relocation type

2019-10-22T15:55:51+00:00

Commit "bpf: Process in-kernel BTF" in linux-next introduced an undefined
__weak symbol, which results in an R_390_GLOB_DAT relocation type. That
is not yet handled by the KASLR relocation code, and the kernel stops with
the message "Unknown relocation type".

Add code to detect and handle R_390_GLOB_DAT relocation types and undefined
symbols.

Fixes: 805bc0bc238f ("s390/kernel: build a relocatable kernel")
Cc:  # v5.2+
Acked-by: Heiko Carstens 
Signed-off-by: Gerald Schaefer 
Signed-off-by: Vasily Gorbik

s390/uaccess: avoid (false positive) compiler warnings

2019-10-11T10:27:25+00:00

Depending on inlining decisions by the compiler, __get/put_user_fn
might become out of line. Then the compiler is no longer able to tell
that size can only be 1,2,4 or 8 due to the check in __get/put_user
resulting in false positives like

./arch/s390/include/asm/uaccess.h: In function ‘__put_user_fn’:
./arch/s390/include/asm/uaccess.h:113:9: warning: ‘rc’ may be used uninitialized in this function [-Wmaybe-uninitialized]
  113 |  return rc;
      |         ^~
./arch/s390/include/asm/uaccess.h: In function ‘__get_user_fn’:
./arch/s390/include/asm/uaccess.h:143:9: warning: ‘rc’ may be used uninitialized in this function [-Wmaybe-uninitialized]
  143 |  return rc;
      |         ^~

These functions are supposed to be always inlined. Mark it as such.

Signed-off-by: Christian Borntraeger 
Signed-off-by: Vasily Gorbik

KVM: s390: mark __insn32_query() as __always_inline

2019-10-05T11:51:22+00:00

__insn32_query() will not compile if the compiler decides to not
inline it, since it contains an inline assembly with an "i" constraint
with variable contents.

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

KVM: s390: fix __insn32_query() inline assembly

2019-10-05T11:51:18+00:00

The inline assembly constraints of __insn32_query() tell the compiler
that only the first byte of "query" is being written to. Intended was
probably that 32 bytes are written to.

Fix and simplify the code and just use a "memory" clobber.

Fixes: d668139718a9 ("KVM: s390: provide query function for instructions returning 32 byte")
Cc: stable@vger.kernel.org # v5.2+
Acked-by: Christian Borntraeger 
Signed-off-by: Heiko Carstens 
Signed-off-by: Vasily Gorbik

s390: update defconfigs

2019-10-04T14:37:33+00:00

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

s390/pci: mark function(s) __always_inline

2019-10-04T14:37:33+00:00

Always inline asm inlines with variable operands for "i" constraints,
since they won't compile if the compiler would decide to not inline
them.

Reported-by: Michal Kubecek 
Signed-off-by: Heiko Carstens 
Signed-off-by: Vasily Gorbik

s390/mm: mark function(s) __always_inline

2019-10-04T14:37:33+00:00

Always inline asm inlines with variable operands for "i" constraints,
since they won't compile if the compiler would decide to not inline
them.

Reported-by: Michal Kubecek 
Signed-off-by: Heiko Carstens 
Signed-off-by: Vasily Gorbik