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Commit 176b1803 authored by Martin Schwidefsky's avatar Martin Schwidefsky Committed by Martin Schwidefsky
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[S390] fix io_return critical section cleanup 



If a machine check interrupts the io interrupt handler on one of the
instructions between io_return and io_leave the critical section
cleanup code will move the return psw to io_work_loop. By doing that
the switch from the asynchronous interrupt stack to the process stack
is skipped. If e.g. TIF_NEED_RESCHED is set things break because
the scheduler is called with the asynchronous interrupts stack.
Moving the psw back to io_return instead fixes the problem.

Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent 35ac734f

arch/s390/kernel/entry.S

+7 −1
Original line number Diff line number Diff line
@@ -964,7 +964,7 @@ cleanup_critical: 
	clc	4(4,%r12),BASED(cleanup_table_io_work_loop)

	bl	BASED(0f)

	clc	4(4,%r12),BASED(cleanup_table_io_work_loop+4)

	bl	BASED(cleanup_io_return)

	bl	BASED(cleanup_io_work_loop)

0:

	br	%r14
@@ -1038,6 +1038,12 @@ cleanup_sysc_leave_insn: 
	.long	sysc_done - 8 + 0x80000000



cleanup_io_return:

	mvc	__LC_RETURN_PSW(4),0(%r12)

	mvc	__LC_RETURN_PSW+4(4),BASED(cleanup_table_io_return)

	la	%r12,__LC_RETURN_PSW

	br	%r14



cleanup_io_work_loop:

	mvc	__LC_RETURN_PSW(4),0(%r12)

	mvc	__LC_RETURN_PSW+4(4),BASED(cleanup_table_io_work_loop)

	la	%r12,__LC_RETURN_PSW

arch/s390/kernel/entry64.S

+7 −1
Original line number Diff line number Diff line
@@ -946,7 +946,7 @@ cleanup_critical: 
	clc	8(8,%r12),BASED(cleanup_table_io_work_loop)

	jl	0f

	clc	8(8,%r12),BASED(cleanup_table_io_work_loop+8)

	jl	cleanup_io_return

	jl	cleanup_io_work_loop

0:

	br	%r14
@@ -1020,6 +1020,12 @@ cleanup_sysc_leave_insn: 
	.quad	sysc_done - 16



cleanup_io_return:

	mvc	__LC_RETURN_PSW(8),0(%r12)

	mvc	__LC_RETURN_PSW+8(8),BASED(cleanup_table_io_return)

	la	%r12,__LC_RETURN_PSW

	br	%r14



cleanup_io_work_loop:

	mvc	__LC_RETURN_PSW(8),0(%r12)

	mvc	__LC_RETURN_PSW+8(8),BASED(cleanup_table_io_work_loop)

	la	%r12,__LC_RETURN_PSW