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| author | Heiko Carstens <hca@linux.ibm.com> | 2021-06-14 14:49:31 +0200 |
|---|---|---|
| committer | Vasily Gorbik <gor@linux.ibm.com> | 2021-06-18 16:41:23 +0200 |
| commit | 88c2510cecb7e2b518e3c4fdf3cf0e13ebe9377c (patch) | |
| tree | 65ecf94b8fad64012b76c139390946b630fa7235 /arch/s390/boot | |
| parent | s390/pci: use register pair instead of register asm (diff) | |
| download | linux-88c2510cecb7e2b518e3c4fdf3cf0e13ebe9377c.tar.xz linux-88c2510cecb7e2b518e3c4fdf3cf0e13ebe9377c.zip | |
s390/ipl_parm: fix program check new psw handling
The __diag308() 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')
| -rw-r--r-- | arch/s390/boot/ipl_parm.c | 19 |
1 files changed, 11 insertions, 8 deletions
diff --git a/arch/s390/boot/ipl_parm.c b/arch/s390/boot/ipl_parm.c index bc1f973e656a..6bf17c623770 100644 --- a/arch/s390/boot/ipl_parm.c +++ b/arch/s390/boot/ipl_parm.c @@ -28,22 +28,25 @@ static inline int __diag308(unsigned long subcode, void *addr) register unsigned long _addr asm("0") = (unsigned long)addr; register unsigned long _rc asm("1") = 0; 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 %[addr],%[subcode],0x308\n" - "1: nopr %%r7\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), [addr] "+d" (_addr), "+d" (_rc) - : [subcode] "d" (subcode) + : [subcode] "d" (subcode), + [psw_old] "a" (&old), + [psw_pgm] "a" (&S390_lowcore.program_new_psw) : "cc", "memory"); - S390_lowcore.program_new_psw = old; return _rc; } |