[S390] cputime: fix overflow on 31 bit systems
The cputime_to_msecs / cputime_to_clock_t and cputime64_to_clock_t
cause fixpoint divide exceptions if the cputime is too large.
On a machine that collected 49.7 days worth of idle time reading
from /proc/stat will generate oopses like this:
Kernel BUG at 001b0c92 [verbose debug info unavailable]
fixpoint divide exception: 0009 [#13] SMP
Modules linked in: ipv6
CPU: 1 Tainted: G D 2.6.27.10 #5
Process cat (pid: 21352, task: 1fb34138, ksp: 1d2a3d98)
Krnl PSW : 070c2000 801b0c92 (show_stat+0x2ca/0x68c)
R:0 T:1 IO:1 EX:1 Key:0 M:1 W:0 P:0 AS:0 CC:2 PM:0
Krnl GPRS: 00000001 00001388 00000bb8 0015d2a1
00000000 00000000 000003e8 0001fd91
00000000 00000000 0000129d eecd2ff0
1cc533b9 0036f780 801b0bce 1d2a3cc0
Krnl Code: 801b0c86: f18890abf198 mvo 171(9,%r9),408(9,%r15)
801b0c8c: 98abf170 lm %r10,%r11,368(%r15)
801b0c90: 1da1 dr %r10,%r1
>801b0c92: 90abf170 stm %r10,%r11,368(%r15)
801b0c96: 98abf190 lm %r10,%r11,400(%r15)
801b0c9a: 1da1 dr %r10,%r1
801b0c9c: 90abf190 stm %r10,%r11,400(%r15)
801b0ca0: 18a3 lr %r10,%r3
Call Trace:
([<00000000001b09f4>] show_stat+0x2c/0x68c)
[<000000000018dcee>] seq_read+0xb2/0x364
[<00000000001a9980>] proc_reg_read+0x68/0x98
[<00000000001705ee>] vfs_read+0x6e/0xe8
[<0000000000170732>] sys_read+0x36/0x78
[<000000000010f750>] sysc_do_restart+0x12/0x16
[<0000000077f3ad6a>] 0x77f3ad6a
<4>---[ end trace 1436ea9559d3de9e ]---
Reported-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
70f5dc514c