From e4b8b3f33fcaa0ed6e6b5482a606091d8cd20beb Mon Sep 17 00:00:00 2001 From: Jan Glauber Date: Tue, 31 Jul 2012 10:52:05 +0200 Subject: s390: add support for runtime instrumentation Allow user-space threads to use runtime instrumentation (RI). To enable RI for a thread there is a new s390 specific system call, sys_s390_runtime_instr, that takes as parameter a realtime signal number. If the RI facility is available the system call sets up a control block for the calling thread with the appropriate permissions for the thread to modify the control block. The user-space thread can then use the store and modify RI instructions to alter the control block and start/stop the instrumentation via RION/RIOFF. If the user specified program buffer runs full RI triggers an external interrupt. The external interrupt is translated to a real-time signal that is delivered to the thread that enabled RI on that CPU. The number of the real-time signal is the number specified in the RI system call. So, user-space can select any available real-time signal number in case the application itself uses real-time signals for other purposes. The kernel saves the RI control blocks on task switch only if the running thread was enabled for RI. Therefore, the performance impact on task switch should be negligible if RI is not used. RI is only enabled for user-space mode and is disabled for the supervisor state. Reviewed-by: Heiko Carstens Signed-off-by: Jan Glauber Signed-off-by: Martin Schwidefsky --- arch/s390/kernel/process.c | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'arch/s390/kernel/process.c') diff --git a/arch/s390/kernel/process.c b/arch/s390/kernel/process.c index 733175373a4c..cb4328e49c75 100644 --- a/arch/s390/kernel/process.c +++ b/arch/s390/kernel/process.c @@ -30,6 +30,7 @@ #include #include #include +#include #include "entry.h" asmlinkage void ret_from_fork(void) asm ("ret_from_fork"); @@ -132,6 +133,7 @@ EXPORT_SYMBOL(kernel_thread); */ void exit_thread(void) { + exit_thread_runtime_instr(); } void flush_thread(void) @@ -170,6 +172,11 @@ int copy_thread(unsigned long clone_flags, unsigned long new_stackp, /* Save access registers to new thread structure. */ save_access_regs(&p->thread.acrs[0]); + /* Don't copy runtime instrumentation info */ + p->thread.ri_cb = NULL; + p->thread.ri_signum = 0; + frame->childregs.psw.mask &= ~PSW_MASK_RI; + #ifndef CONFIG_64BIT /* * save fprs to current->thread.fp_regs to merge them with -- cgit v1.2.3 From f6e38691a2f410e3333941e535c7b20352f98ddb Mon Sep 17 00:00:00 2001 From: Heiko Carstens Date: Fri, 14 Sep 2012 13:45:24 +0200 Subject: s390/process: add missing header include Add appropriate header file: arch/s390/kernel/process.c:327:15: warning: symbol 'arch_align_stack' was not declared. Signed-off-by: Heiko Carstens Signed-off-by: Martin Schwidefsky --- arch/s390/kernel/process.c | 1 + 1 file changed, 1 insertion(+) (limited to 'arch/s390/kernel/process.c') diff --git a/arch/s390/kernel/process.c b/arch/s390/kernel/process.c index cb4328e49c75..5024be27df44 100644 --- a/arch/s390/kernel/process.c +++ b/arch/s390/kernel/process.c @@ -26,6 +26,7 @@ #include #include #include +#include #include #include #include -- cgit v1.2.3