BMC/Intel-BMC/linux.git/arch/s390/include/asm/processor.h, branch dev-4.3

s390/sclp: convert early sclp console code to C

2015-07-29T07:11:39+00:00

The 31-bit assembler code for the early sclp console is error prone as git commit fde24b54d976cc123506695c17db01438a11b673 "s390/sclp: clear upper register halves in _sclp_print_early" has shown. Convert the assembler code to C. Signed-off-by: Martin Schwidefsky

s390/kernel: lazy restore fpu registers

2015-07-22T07:58:01+00:00

Improve the save and restore behavior of FPU register contents to use the vector extension within the kernel. The kernel does not use floating-point or vector registers and, therefore, saving and restoring the FPU register contents are performed for handling signals or switching processes only. To prepare for using vector instructions and vector registers within the kernel, enhance the save behavior and implement a lazy restore at return to user space from a system call or interrupt. To implement the lazy restore, the save_fpu_regs() sets a CPU information flag, CIF_FPU, to indicate that the FPU registers must be restored. Saving and setting CIF_FPU is performed in an atomic fashion to be interrupt-safe. When the kernel wants to use the vector extension or wants to change the FPU register state for a task during signal handling, the save_fpu_regs() must be called first. The CIF_FPU flag is also set at process switch. At return to user space, the FPU state is restored. In particular, the FPU state includes the floating-point or vector register contents, as well as, vector-enablement and floating-point control. The FPU state restore and clearing CIF_FPU is also performed in an atomic fashion. For KVM, the restore of the FPU register state is performed when restoring the general-purpose guest registers before the SIE instructions is started. Because the path towards the SIE instruction is interruptible, the CIF_FPU flag must be checked again right before going into SIE. If set, the guest registers must be reloaded again by re-entering the outer SIE loop. This is the same behavior as if the SIE critical section is interrupted. Signed-off-by: Hendrik Brueckner Signed-off-by: Martin Schwidefsky

s390/kernel: introduce fpu-internal.h with fpu helper functions

2015-07-22T07:58:00+00:00

Introduce a new structure to manage FP and VX registers. Refactor the save and restore of floating point and vector registers with a set of helper functions in fpu-internal.h. Signed-off-by: Hendrik Brueckner Signed-off-by: Martin Schwidefsky

s390/kernel: move EX_TABLE macros to linkage.h header file

2015-07-22T07:57:59+00:00

Move the EX_TABLE macro definitions from the processor.h to the linkage.h header file. It helps to reduce circular header file dependencies. Signed-off-by: Hendrik Brueckner Signed-off-by: Martin Schwidefsky

s390: remove 31 bit support

2015-03-25T10:49:33+00:00

Remove the 31 bit support in order to reduce maintenance cost and effectively remove dead code. Since a couple of years there is no distribution left that comes with a 31 bit kernel. The 31 bit kernel also has been broken since more than a year before anybody noticed. In addition I added a removal warning to the kernel shown at ipl for 5 minutes: a960062e5826 ("s390: add 31 bit warning message") which let everybody know about the plan to remove 31 bit code. We didn't get any response. Given that the last 31 bit only machine was introduced in 1999 let's remove the code. Anybody with 31 bit user space code can still use the compat mode. Signed-off-by: Heiko Carstens Signed-off-by: Martin Schwidefsky

s390: reintroduce diag 44 calls for cpu_relax()

2015-01-29T08:19:16+00:00

Christian Borntraeger reported that the now missing diag 44 calls (voluntary time slice end) does cause a performance regression for stop_machine() calls if a machine has more virtual cpus than the host has physical cpus. This patch mainly reverts 57f2ffe14fd125c2 ("s390: remove diag 44 calls from cpu_relax()") with the exception that we still do not issue diag 44 calls if running with smt enabled. Due to group scheduling algorithms when running in LPAR this would lead to significant latencies. However, when running in LPAR we do not have more virtual than physical cpus. Reported-and-tested-by: Christian Borntraeger Signed-off-by: Heiko Carstens Signed-off-by: Martin Schwidefsky

s390: remove diag 44 calls from cpu_relax()

2014-11-28T08:47:49+00:00

Simplify cpu_relax() to a simple barrier(). Performance wise this doesn't seem to make any big difference anymore, since nearly all lock variants have directed yield semantics in the meantime. Also this makes s390 behave like all other architectures. Signed-off-by: Heiko Carstens Signed-off-by: Martin Schwidefsky

s390: add support for vector extension

2014-10-09T07:14:13+00:00

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

2014-10-09T07:14:03+00:00

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

2014-10-09T07:14:02+00:00

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