From bcc6525fb23d2cec7ffdf908d98826a66823bcb2 Mon Sep 17 00:00:00 2001 From: Christian Borntraeger Date: Fri, 13 Nov 2009 15:43:54 +0100 Subject: [S390] s390: fix single stepping on svc0 On s390 there are two ways of specifying the system call number for the svc instruction. The standard way is to use the immediate field in the instruction (or to use EXecute for values unknown during assemble time). This can encode 256 system calls. The kernel ABI also allows to put the system call number in r1 and then execute svc 0 to enable system call numbers > 255. It turns out that single stepping svc 0 is broken, since the PER program check handler uses r1. We have to use a different register. Signed-off-by: Christian Borntraeger Signed-off-by: Martin Schwidefsky --- arch/s390/kernel/entry.S | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'arch/s390/kernel/entry.S') diff --git a/arch/s390/kernel/entry.S b/arch/s390/kernel/entry.S index f43d2ee54464..48215d15762b 100644 --- a/arch/s390/kernel/entry.S +++ b/arch/s390/kernel/entry.S @@ -565,10 +565,10 @@ pgm_svcper: lh %r7,0x8a # get svc number from lowcore l %r9,__LC_THREAD_INFO # load pointer to thread_info struct TRACE_IRQS_OFF - l %r1,__TI_task(%r9) - mvc __THREAD_per+__PER_atmid(2,%r1),__LC_PER_ATMID - mvc __THREAD_per+__PER_address(4,%r1),__LC_PER_ADDRESS - mvc __THREAD_per+__PER_access_id(1,%r1),__LC_PER_ACCESS_ID + l %r8,__TI_task(%r9) + mvc __THREAD_per+__PER_atmid(2,%r8),__LC_PER_ATMID + mvc __THREAD_per+__PER_address(4,%r8),__LC_PER_ADDRESS + mvc __THREAD_per+__PER_access_id(1,%r8),__LC_PER_ACCESS_ID oi __TI_flags+3(%r9),_TIF_SINGLE_STEP # set TIF_SINGLE_STEP TRACE_IRQS_ON stosm __SF_EMPTY(%r15),0x03 # reenable interrupts -- cgit v1.2.3