redonkable/alistair23-linux
redonkable/alistair23-linux
1
0
Fork 0
Code Releases Activity

s390/fpu: add static FPU save area for init_task

Browse source 
Previously, the init task did not have an allocated FPU save area and
saving an FPU state was not possible.  Now if the vector extension is
always enabled, provide a static FPU save area to save FPU states of
vector instructions that can be executed quite early.

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:
Hendrik Brueckner 2015-09-29 17:53:22 +02:00 committed by Martin Schwidefsky
parent b5510d9b68
commit 0ac277790e
3 changed files with 6 additions and 4 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

2
arch/s390/include/asm/processor.h
View file

@ -139,8 +139,10 @@ struct stack_frame {
#define ARCH_MIN_TASKALIGN 8
extern __vector128 init_task_fpu_regs[__NUM_VXRS];
#define INIT_THREAD { \
.ksp = sizeof(init_stack) + (unsigned long) &init_stack, \
.fpu.regs = (void *)&init_task_fpu_regs, \
}
/*

4
arch/s390/kernel/entry.S
View file

@ -762,8 +762,6 @@ ENTRY(save_fpu_regs)
stfpc __THREAD_FPU_fpc(%r2)
.Lsave_fpu_regs_fpc_end:
lg %r3,__THREAD_FPU_regs(%r2)
ltgr %r3,%r3
jz .Lsave_fpu_regs_done # no save area -> set CIF_FPU
tm __LC_MACHINE_FLAGS+5,4 # MACHINE_HAS_VX
jz .Lsave_fpu_regs_fp # no -> store FP regs
.Lsave_fpu_regs_vx_low:
@ -1193,8 +1191,6 @@ cleanup_critical:
stfpc __THREAD_FPU_fpc(%r2)
1: # Load register save area and check if VX is active
lg %r3,__THREAD_FPU_regs(%r2)
ltgr %r3,%r3
jz 5f # no save area -> set CIF_FPU
tm __LC_MACHINE_FLAGS+5,4 # MACHINE_HAS_VX
jz 4f # no VX -> store FP regs
2: # Store vector registers (V0-V15)

4
arch/s390/kernel/process.c
View file

@ -23,6 +23,7 @@
#include <linux/kprobes.h>
#include <linux/random.h>
#include <linux/module.h>
#include <linux/init_task.h>
#include <asm/io.h>
#include <asm/processor.h>
#include <asm/vtimer.h>
@ -36,6 +37,9 @@
asmlinkage void ret_from_fork(void) asm ("ret_from_fork");
/* FPU save area for the init task */
__vector128 init_task_fpu_regs[__NUM_VXRS] __init_task_data;
/*
* Return saved PC of a blocked thread. used in kernel/sched.
* resume in entry.S does not create a new stack frame, it