Commit 3241d3eb authored by Heiko Carstens's avatar Heiko Carstens Committed by Martin Schwidefsky
Browse files

s390: rework __switch_to() to allow larger task_struct offsets 



If GCC_PLUGIN_RANDSTRUCT is enabled the members of task_struct will be
shuffled around. The offsets of the "pid" and "stack" members within
task_struct may not necessarily fit into 12 bits anymore, which causes
compile errors within __switch_to, since instructions are used, which
only have a 12 bit displacement field.

Therefore rework __switch_to, to allow for larger offsets.

Signed-off-by: default avatarHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent 38389ec8

arch/s390/kernel/entry.S

+7 −8
Original line number Diff line number Diff line
@@ -180,18 +180,17 @@ _PIF_WORK = (_PIF_PER_TRAP | _PIF_SYSCALL_RESTART) 
 */

ENTRY(__switch_to)

	stmg	%r6,%r15,__SF_GPRS(%r15)	# store gprs of prev task

	lgr	%r1,%r2

	aghi	%r1,__TASK_thread		# thread_struct of prev task

	lg	%r5,__TASK_stack(%r3)		# start of kernel stack of next

	stg	%r15,__THREAD_ksp(%r1)		# store kernel stack of prev

	lgr	%r1,%r3

	aghi	%r1,__TASK_thread		# thread_struct of next task

	lghi	%r4,__TASK_stack

	lghi	%r1,__TASK_thread

	lg	%r5,0(%r4,%r3)			# start of kernel stack of next

	stg	%r15,__THREAD_ksp(%r1,%r2)	# store kernel stack of prev

	lgr	%r15,%r5

	aghi	%r15,STACK_INIT			# end of kernel stack of next

	stg	%r3,__LC_CURRENT		# store task struct of next

	stg	%r15,__LC_KERNEL_STACK		# store end of kernel stack

	lg	%r15,__THREAD_ksp(%r1)		# load kernel stack of next

	mvc	__LC_CURRENT_PID(4,%r0),__TASK_pid(%r3) # store pid of next

	lg	%r15,__THREAD_ksp(%r1,%r3)	# load kernel stack of next

	aghi	%r3,__TASK_pid

	mvc	__LC_CURRENT_PID(4,%r0),0(%r3)	# store pid of next

	lmg	%r6,%r15,__SF_GPRS(%r15)	# load gprs of next task

	TSTMSK	__LC_MACHINE_FLAGS,MACHINE_FLAG_LPP

	bzr	%r14

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