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| author | Heiko Carstens <hca@linux.ibm.com> | 2021-06-14 22:40:43 +0300 |
|---|---|---|
| committer | Vasily Gorbik <gor@linux.ibm.com> | 2021-06-18 17:41:24 +0300 |
| commit | 86807f348f418a84970eebb8f9912a7eea16b497 (patch) | |
| tree | 7d90be771c14b23742ecd8dd4523a85767b147cd /arch/s390/boot/mem_detect.c | |
| parent | d99aea73b4de2357095e1059637ef5427e9473e8 (diff) | |
| download | linux-86807f348f418a84970eebb8f9912a7eea16b497.tar.xz | |
s390/mem_detect: fix diag260() program check new psw handling
The __diag260() inline asm temporarily changes the program check new
psw to redirect a potential program check on the diag instruction.
Restoring of the program check new psw is done in C code behind the
inline asm.
This can be problematic, especially if the function is inlined, since
the compiler can reorder instructions in such a way that a different
instruction, which may result in a program check, might be executed
before the program check new psw has been restored.
To avoid such a scenario move restoring into the inline asm. For
consistency reasons move also saving of the original program check new
psw into the inline asm.
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Diffstat (limited to 'arch/s390/boot/mem_detect.c')
| -rw-r--r-- | arch/s390/boot/mem_detect.c | 19 |
1 files changed, 11 insertions, 8 deletions
diff --git a/arch/s390/boot/mem_detect.c b/arch/s390/boot/mem_detect.c index 40168e59abd3..3f093556dc3b 100644 --- a/arch/s390/boot/mem_detect.c +++ b/arch/s390/boot/mem_detect.c @@ -69,24 +69,27 @@ static int __diag260(unsigned long rx1, unsigned long rx2) register unsigned long _ry asm("4") = 0x10; /* storage configuration */ int rc = -1; /* fail */ unsigned long reg1, reg2; - psw_t old = S390_lowcore.program_new_psw; + psw_t old; asm volatile( + " mvc 0(16,%[psw_old]),0(%[psw_pgm])\n" " epsw %0,%1\n" - " st %0,%[psw_pgm]\n" - " st %1,%[psw_pgm]+4\n" + " st %0,0(%[psw_pgm])\n" + " st %1,4(%[psw_pgm])\n" " larl %0,1f\n" - " stg %0,%[psw_pgm]+8\n" + " stg %0,8(%[psw_pgm])\n" " diag %[rx],%[ry],0x260\n" " ipm %[rc]\n" " srl %[rc],28\n" - "1:\n" + "1: mvc 0(16,%[psw_pgm]),0(%[psw_old])\n" : "=&d" (reg1), "=&a" (reg2), - [psw_pgm] "=Q" (S390_lowcore.program_new_psw), + "+Q" (S390_lowcore.program_new_psw), + "=Q" (old), [rc] "+&d" (rc), [ry] "+d" (_ry) - : [rx] "d" (_rx1), "d" (_rx2) + : [rx] "d" (_rx1), "d" (_rx2), + [psw_old] "a" (&old), + [psw_pgm] "a" (&S390_lowcore.program_new_psw) : "cc", "memory"); - S390_lowcore.program_new_psw = old; return rc == 0 ? _ry : -1; } |