Commit 450e47da authored Oct 09, 2012 by Martin Schwidefsky

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

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>

parent fc7e48aa

arch/s390/kernel/entry64.S

+1 −1

Original line number	Diff line number	Diff line
		@@ -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