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s390/cpumf: rework program parameter setting to detect guest samples

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The program parameter can be used to mark hardware samples with
some token.  Previously, it was used to mark guest samples only.

Improve the program parameter doubleword by combining two parts,
the leftmost LPP part and the rightmost PID part.  Set the PID
part for processes by using the task PID.
To distinguish host and guest samples for the kernel (PID part
is zero), the guest must always set the program paramater to a
non-zero value.  Use the leftmost bit in the LPP part of the
program parameter to be able to detect guest kernel samples.

[brueckner@linux.vnet.ibm.com]: Split __LC_CURRENT and introduced
__LC_LPP. Corrected __LC_CURRENT users and adjusted assembler parts.
And updated the commit message accordingly.

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
This commit is contained in:
Christian Borntraeger
2015-10-06 18:06:15 +02:00
committed by Martin Schwidefsky
parent 6a62b485ea
commit e22cf8ca6f
8 changed files with 40 additions and 24 deletions
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2
arch/s390/kernel/smp.c
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@@ -262,6 +262,8 @@ static void pcpu_attach_task(struct pcpu *pcpu, struct task_struct *tsk)
+ THREAD_SIZE - STACK_FRAME_OVERHEAD - sizeof(struct pt_regs);
lc->thread_info = (unsigned long) task_thread_info(tsk);
lc->current_task = (unsigned long) tsk;
lc->lpp = LPP_MAGIC;
lc->current_pid = tsk->pid;
lc->user_timer = ti->user_timer;
lc->system_timer = ti->system_timer;
lc->steal_timer = 0;