kernel.git/arch/s390/kernel/smp.c, branch linux-3.19.y

s390/ftrace,kprobes: allow to patch first instruction

2014-10-27T12:27:27Z

If the function tracer is enabled, allow to set kprobes on the first instruction of a function (which is the function trace caller): If no kprobe is set handling of enabling and disabling function tracing of a function simply patches the first instruction. Either it is a nop (right now it's an unconditional branch, which skips the mcount block), or it's a branch to the ftrace_caller() function. If a kprobe is being placed on a function tracer calling instruction we encode if we actually have a nop or branch in the remaining bytes after the breakpoint instruction (illegal opcode). This is possible, since the size of the instruction used for the nop and branch is six bytes, while the size of the breakpoint is only two bytes. Therefore the first two bytes contain the illegal opcode and the last four bytes contain either "0" for nop or "1" for branch. The kprobes code will then execute/simulate the correct instruction. Instruction patching for kprobes and function tracer is always done with stop_machine(). Therefore we don't have any races where an instruction is patched concurrently on a different cpu. Besides that also the program check handler which executes the function trace caller instruction won't be executed concurrently to any stop_machine() execution. This allows to keep full fault based kprobes handling which generates correct pt_regs contents automatically. Signed-off-by: Heiko Carstens Signed-off-by: Martin Schwidefsky

s390/kdump: add support for vector extension

2014-10-09T07:14:16Z

With this patch for kdump the s390 vector registers are stored into the prepared save areas in the old kernel and into the REGSET_VX_LOW and REGSET_VX_HIGH ELF notes for /proc/vmcore in the new kernel. The NT_S390_VXRS_LOW note contains the lower halves of the first 16 vector registers 0-15. The higher halves are stored in the floating point register ELF note. The NT_S390_VXRS_HIGH contains the full vector registers 16-31. The kernel provides a save area for storing vector register in case of machine checks. A pointer to this save are is stored in the CPU lowcore at offset 0x11b0. This save area is also used to save the registers for kdump. In case of a dumped crashed kdump those areas are used to extract the registers of the production system. The vector registers for remote CPUs are stored using the "store additional status at address" SIGP. For the dump CPU the vector registers are stored with the VSTM instruction. With this patch also zfcpdump stores the vector registers. Reviewed-by: Heiko Carstens Signed-off-by: Michael Holzheu Signed-off-by: Martin Schwidefsky

s390: add support for vector extension

2014-10-09T07:14:13Z

The vector extension introduces 32 128-bit vector registers and a set of instruction to operate on the vector registers. The kernel can control the use of vector registers for the problem state program with a bit in control register 0. Once enabled for a process the kernel needs to retain the content of the vector registers on context switch. The signal frame is extended to include the vector registers. Two new register sets NT_S390_VXRS_LOW and NT_S390_VXRS_HIGH are added to the regset interface for the debugger and core dumps. Signed-off-by: Martin Schwidefsky

s390/idle: consolidate idle functions and definitions

2014-10-09T07:14:03Z

Move the C functions and definitions related to the idle state handling to arch/s390/include/asm/idle.h and arch/s390/kernel/idle.c. The function s390_get_idle_time is renamed to arch_cpu_idle_time and vtime_stop_cpu to enabled_wait. Signed-off-by: Martin Schwidefsky

s390/nohz: use a per-cpu flag for arch_needs_cpu

2014-10-09T07:14:02Z

Move the nohz_delay bit from the s390_idle data structure to the per-cpu flags. Clear the nohz delay flag in __cpu_disable and remove the cpu hotplug notifier that used to do this. Signed-off-by: Martin Schwidefsky

s390/rwlock: use directed yield for write-locked rwlocks

2014-09-25T08:52:05Z

Add an owner field to the arch_rwlock_t to be able to pass the timeslice of a virtual CPU with diagnose 0x9c to the lock owner in case the rwlock is write-locked. The undirected yield in case the rwlock is acquired writable but the lock is read-locked is removed. Signed-off-by: Martin Schwidefsky

s390/smp: Avoid busy loop after halt and "begin" on z/VM

2014-05-20T06:58:45Z

Currently the smp_stop_cpu() function for SMP kernels enters a busy loop when "begin" is entered on the z/VM console after Linux is halted. To avoid this behavior, use the non-SMP variant of smp_stop_cpu() which stops the CPU again after "begin" is entered. As a side effect we now have consistent behavior for SMP and non-SMP Linux. Signed-off-by: Michael Holzheu Signed-off-by: Martin Schwidefsky

s390/dump: Remove CONFIG_ZFCPDUMP

2014-05-20T06:58:43Z

Currently there are two s390 kernel dump config options "CONFIG_ZFCPDUMP" and "CONFIG_CRASH_DUMP". In order to keep things simple and because the "CONFIG_ZFCPDUMP" option already has a dependency to "CONFIG_CRASH_DUMP" remove the CONFIG_ZFCPDUMP option. Signed-off-by: Michael Holzheu Reviewed-by: Eric Farman Signed-off-by: Martin Schwidefsky

s390/spinlock: optimize spinlock code sequence

2014-05-20T06:58:42Z

Use lowcore constant to improve the code generated for spinlocks. [ Martin Schwidefsky: patch breakdown and code beautification ] Signed-off-by: Philipp Hachtmann Signed-off-by: Martin Schwidefsky

s390/smp: fix smp_stop_cpu() for !CONFIG_SMP

2014-04-09T08:19:12Z

smp_stop_cpu() should stop the current cpu even for !CONFIG_SMP. Otherwise machine_halt() will return and and the machine generates a panic instread of simply stopping the current cpu: Kernel panic - not syncing: Attempted to kill init! exitcode=0x00000000 CPU: 0 PID: 1 Comm: systemd-shutdow Not tainted 3.14.0-01527-g2b6ef16a6bc5 #10 [...] Call Trace: ([<0000000000110db0>] show_trace+0xf8/0x158) [<0000000000110e7a>] show_stack+0x6a/0xe8 [<000000000074dba8>] panic+0xe4/0x268 [<0000000000140570>] do_exit+0xa88/0xb2c [<000000000016e12c>] SyS_reboot+0x1f0/0x234 [<000000000075da70>] sysc_nr_ok+0x22/0x28 [<000000007d5a09b4>] 0x7d5a09b4 Signed-off-by: Heiko Carstens Signed-off-by: Martin Schwidefsky