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s390/entry: fix svc number for TIF_SYSCALL system call restart

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The load of the svc number in the TIF_SYSCALL restart path needs to be
done with an instruction that loads all 64 bits of %r1, 'lh' only loads
32 bits. If the upper half of %r1 is not zero and has the msb set,
entry64.S will try to execute an svc with a really large number.
What will be in the upper half of %r1 depends on the code generated by
gcc for the functions on the do_signal() callchain.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
This commit is contained in:
Martin Schwidefsky 2012-10-09 13:33:53 +02:00
parent fc7e48aad3
commit 450e47da67
1 changed files with 1 additions and 1 deletions
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arch/s390/kernel/entry64.S
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@ -295,7 +295,7 @@ sysc_sigpending:
jno sysc_return
lmg %r2,%r7,__PT_R2(%r11) # load svc arguments
lghi %r8,0 # svc 0 returns -ENOSYS
lh %r1,__PT_INT_CODE+2(%r11) # load new svc number
llgh %r1,__PT_INT_CODE+2(%r11) # load new svc number
cghi %r1,NR_syscalls
jnl sysc_nr_ok # invalid svc number -> do svc 0
slag %r8,%r1,2