kernel.git/arch/s390/kernel/entry64.S, branch linux-2.6.28.y

[S390] fix system call parameter functions.

2008-11-27T10:06:56Z

syscall_get_nr() currently returns a valid result only if the call chain of the traced process includes do_syscall_trace_enter(). But collect_syscall() can be called for any sleeping task, the result of syscall_get_nr() in general is completely bogus. To make syscall_get_nr() work for any sleeping task the traps field in pt_regs is replace with svcnr - the system call number the process is executing. If svcnr == 0 the process is not on a system call path. The syscall_get_arguments and syscall_set_arguments use regs->gprs[2] for the first system call parameter. This is incorrect since gprs[2] may have been overwritten with the system call number if the call chain includes do_syscall_trace_enter. Use regs->orig_gprs2 instead. Signed-off-by: Martin Schwidefsky

[S390] ftrace: fix kernel stack backchain walking

2008-11-14T17:18:53Z

With CONFIG_IRQSOFF_TRACER the trace_hardirqs_off() function includes a call to __builtin_return_address(1). But we calltrace_hardirqs_off() from early entry code. There we have just a single stack frame. So this results in a kernel stack backchain walk that would walk beyond the kernel stack. Following the NULL terminated backchain this results in a lowcore read access. To fix this we simply call trace_hardirqs_off_caller() and pass the current instruction pointer. Signed-off-by: Heiko Carstens Signed-off-by: Martin Schwidefsky

[S390] ptrace changes

2008-10-10T19:33:57Z

* System call parameter and result access functions * Add tracehook calls * Split syscall_trace into two functions do_syscall_trace_enter and do_syscall_trace_exit Signed-off-by: Martin Schwidefsky

[S390] s390-kvm: leave sie context on work. Removes preemption requirement

2008-05-07T07:23:01Z

From: Martin Schwidefsky This patch fixes a bug with cpu bound guest on kvm-s390. Sometimes it was impossible to deliver a signal to a spinning guest. We used preemption as a circumvention. The preemption notifiers called vcpu_load, which checked for pending signals and triggered a host intercept. But even with preemption, a sigkill was not delivered immediately. This patch changes the low level host interrupt handler to check for the SIE instruction, if TIF_WORK is set. In that case we change the instruction pointer of the return PSW to rerun the vcpu_run loop. The kvm code sees an intercept reason 0 if that happens. This patch adds accounting for these types of intercept as well. The advantages: - works with and without preemption - signals are delivered immediately - much better host latencies without preemption Acked-by: Carsten Otte Signed-off-by: Christian Borntraeger Signed-off-by: Martin Schwidefsky

[S390] s390: Optimize user and work TIF check

2008-05-07T07:23:00Z

On return from syscall or interrupt, we have to check if we return to userspace (likely) and if there is work todo (less likely) to decide if we handle the work. We can optimize this check: we first check for the less likely work case and then check for userspace. This patch is also a preparation for an additional patch, that fixes a bug in KVM dealing with cpu bound guests. Signed-off-by: Martin Schwidefsky

signals: s390: renumber TIF_RESTORE_SIGMASK

2008-04-30T15:29:37Z

TIF_RESTORE_SIGMASK no longer needs to be in the _TIF_WORK_* masks. Those low bits are scarce, and are all used up now. Renumber TIF_RESTORE_SIGMASK to free one up. Signed-off-by: Roland McGrath Cc: Oleg Nesterov Cc: Ingo Molnar Cc: Thomas Gleixner Cc: Martin Schwidefsky Cc: Heiko Carstens Cc: "Luck, Tony" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

[S390] kernel: show last breaking-event-address on oops

2008-04-17T05:47:07Z

Newer s390 models have a breaking-event-address-recording register. Each time an instruction causes a break in the sequential instruction execution, the address is saved in that hardware register. On a program interrupt the address is copied to the lowcore address 272-279, which makes it software accessible. This patch changes the program check handler and the stack overflow checker to copy the value into the pt_regs argument. The oops output is enhanced to show the last known breaking address. It might give additional information if the stack trace is corrupted. The feature is only available on 64 bit. The new oops output looks like: [---------snip----------] Modules linked in: vmcp sunrpc qeth_l2 dm_mod qeth ccwgroup CPU: 2 Not tainted 2.6.24zlive-host #8 Process modprobe (pid: 4788, task: 00000000bf3d8718, ksp: 00000000b2b0b8e0) Krnl PSW : 0704200180000000 000003e000020028 (vmcp_init+0x28/0xe4 [vmcp]) R:0 T:1 IO:1 EX:1 Key:0 M:1 W:0 P:0 AS:0 CC:2 PM:0 EA:3 Krnl GPRS: 0000000004000002 000003e000020000 0000000000000000 0000000000000001 000000000015734c ffffffffffffffff 000003e0000b3b00 0000000000000000 000003e00007ca30 00000000b5bb5d40 00000000b5bb5800 000003e0000b3b00 000003e0000a2000 00000000003ecf50 00000000b2b0bd50 00000000b2b0bcb0 Krnl Code: 000003e000020018: c0c000040ff4 larl %r12,3e0000a2000 000003e00002001e: e3e0f0000024 stg %r14,0(%r15) 000003e000020024: a7f40001 brc 15,3e000020026 >000003e000020028: e310c0100004 lg %r1,16(%r12) 000003e00002002e: c020000413dc larl %r2,3e0000a27e6 000003e000020034: c0a00004aee6 larl %r10,3e0000b5e00 000003e00002003a: a7490001 lghi %r4,1 000003e00002003e: a75900f0 lghi %r5,240 Call Trace: ([<000000000014b300>] blocking_notifier_call_chain+0x2c/0x40) [<000000000015735c>] sys_init_module+0x19d8/0x1b08 [<0000000000110afc>] sysc_noemu+0x10/0x16 [<000002000011cda2>] 0x2000011cda2 Last Breaking-Event-Address: [<000003e000020024>] vmcp_init+0x24/0xe4 [vmcp] [---------snip----------] Signed-off-by: Christian Borntraeger Signed-off-by: Martin Schwidefsky Signed-off-by: Heiko Carstens

[S390] Fix couple of section mismatches.

2008-02-05T15:50:56Z

Fix couple of section mismatches. And since we touch the code anyway change the IPL code to use C99 initializers. Cc: Michael Holzheu Signed-off-by: Heiko Carstens Signed-off-by: Martin Schwidefsky

[S390] Fix kernel preemption.

2007-11-20T10:13:46Z

When returning from IRQ handling and TIF_NEED_RESCHED is set we must call preempt_schedule_irq() instead of schedule(). Otherwise the BKL might be unlocked in schedule() and therfore everything that relies on the BKL is broken. Signed-off-by: Heiko Carstens Signed-off-by: Martin Schwidefsky

[S390] Fix irq tracing and lockdep_sys_exit calls.

2007-11-20T10:13:45Z

Current support for TRACE_IRQFLAGS and lockdep_sys_exit is broken. IRQ flag tracing is broken for program checks. Even worse is that the newly introduced calls to lockdep_sys_exit are in the critical section code which is not supposed to call any C functions. In addition the checks if locks are still held are also done when returning to kernel code which is broken as well. Fix all this by disabling interrupts and machine checks at the exit paths and then do the appropriate checks and calls. Signed-off-by: Heiko Carstens Signed-off-by: Martin Schwidefsky