linux/arch/s390
Michael Holzheu 37e37c20ab [S390] Fix stfle() lowcore protection problem
The stfle() function writes into lowcore memory when stfl_fac_list
is initialized with "S390_lowcore.stfl_fac_list = 0". For older
compilers this triggers a lowcore exception. With newer compilers
and "-OXX" compile option the bug does not show up because
the "S390_lowcore.stfl_fac_list" initialization is removed by the
compiler. The reason for thatis the incorrect "=m"
(S390_lowcore.stfl_fac_list) constraint in the stfl inline assembly.

The following shows the disassembly of the stfle() optimized code
that is inlined in the lgr_info_get() function:

000000000011325c <lgr_info_get>:
  11325c:       eb 9f f0 60 00 24       stmg    %r9,%r15,96(%r15)
  113262:       c0 d0 00 29 0e 47       larl    %r13,634ef0 <servi..>
  113268:       a7 f1 3f c0             tml     %r15,16320
  11326c:       b9 04 00 ef             lgr     %r14,%r15
  113270:       a7 84 00 01             je      113272 <lgr_info_g..>
  113274:       a7 fb ff c0             aghi    %r15,-64
  113278:       b9 04 00 c2             lgr     %r12,%r2
  11327c:       a7 29 00 01             lghi    %r2,1
  113280:       e3 e0 f0 98 00 24       stg     %r14,152(%r15)
  113286:       d7 97 c0 00 c0 00       xc      0(152,%r12),0(%r12)
  11328c:       c0 e5 00 28 db 4c       brasl   %r14,62e924 <add_e..>
  113292:       b2 b1 00 00             stfl    0

To fix the problem we now clear the S390_lowcore.stfl_fac_list at
startup in "head.S" for all machine types before lowcore protection
is enabled.

In addition to that the "=m" constraint is replaced by "+m".

Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2012-04-11 14:28:26 +02:00
..
appldata sched/accounting: Change cpustat fields to an array 2011-12-06 09:06:38 +01:00
boot [S390] Remove Kerntypes leftovers 2011-12-27 11:27:12 +01:00
crypto Disintegrate asm/system.h for S390 2012-03-28 18:30:02 +01:00
hypfs switch open-coded instances of d_make_root() to new helper 2012-03-20 21:29:35 -04:00
include/asm [S390] Fix stfle() lowcore protection problem 2012-04-11 14:28:26 +02:00
kernel [S390] Fix stfle() lowcore protection problem 2012-04-11 14:28:26 +02:00
kvm Disintegrate and delete asm/system.h 2012-03-28 15:58:21 -07:00
lib [S390] rework idle code 2012-03-11 11:59:28 -04:00
math-emu s390: change to new flag variable 2011-03-17 14:02:57 +01:00
mm [S390] fix tlb flushing for page table pages 2012-04-11 14:28:24 +02:00
oprofile Disintegrate and delete asm/system.h 2012-03-28 15:58:21 -07:00
defconfig [S390] update default configuration 2012-04-11 14:28:25 +02:00
Kbuild [S390] make arch/s390 subdirectories depend on config option 2011-12-27 11:27:12 +01:00
Kconfig [S390] fix tlb flushing for page table pages 2012-04-11 14:28:24 +02:00
Kconfig.debug [S390] Write protect module text and RO data 2011-03-15 17:08:23 +01:00
Makefile [S390] cleanup entry point definition 2012-01-18 18:03:41 +01:00