[S390] vdso: clock_gettime of CLOCK_THREAD_CPUTIME_ID with noexec=on
The combination of noexec=on and a clock_gettime call with clock id CLOCK_THREAD_CPUTIME_ID is broken. The vdso code switches to the access register mode to get access to the per-cpu data structure to execute the magic ectg instruction. After the ectg instruction the code always switches back to the primary mode but for noexec=on the correct mode is the secondary mode. The effect of the bug is that the user space program looses the access to all mappings without PROT_EXEC, e.g. the stack. The problem is fixed by restoring the mode that has been active before the switch to the access register mode. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
This commit is contained in:
parent
3a6ba4600d
commit
1277580fe5
1 changed files with 9 additions and 2 deletions
|
@ -88,10 +88,17 @@ __kernel_clock_gettime:
|
||||||
llilh %r4,0x0100
|
llilh %r4,0x0100
|
||||||
sar %a4,%r4
|
sar %a4,%r4
|
||||||
lghi %r4,0
|
lghi %r4,0
|
||||||
|
epsw %r5,0
|
||||||
sacf 512 /* Magic ectg instruction */
|
sacf 512 /* Magic ectg instruction */
|
||||||
.insn ssf,0xc80100000000,__VDSO_ECTG_BASE(4),__VDSO_ECTG_USER(4),4
|
.insn ssf,0xc80100000000,__VDSO_ECTG_BASE(4),__VDSO_ECTG_USER(4),4
|
||||||
sacf 0
|
tml %r5,0x4000
|
||||||
sar %a4,%r2
|
jo 11f
|
||||||
|
tml %r5,0x8000
|
||||||
|
jno 10f
|
||||||
|
sacf 256
|
||||||
|
j 11f
|
||||||
|
10: sacf 0
|
||||||
|
11: sar %a4,%r2
|
||||||
algr %r1,%r0 /* r1 = cputime as TOD value */
|
algr %r1,%r0 /* r1 = cputime as TOD value */
|
||||||
mghi %r1,1000 /* convert to nanoseconds */
|
mghi %r1,1000 /* convert to nanoseconds */
|
||||||
srlg %r1,%r1,12 /* r1 = cputime in nanosec */
|
srlg %r1,%r1,12 /* r1 = cputime in nanosec */
|
||||||
|
|
Reference in a new issue