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authorHendrik Brueckner <brueckner@linux.vnet.ibm.com>2015-09-29 17:53:22 +0200
committerMartin Schwidefsky <schwidefsky@de.ibm.com>2015-10-14 14:32:08 +0200
commit0ac277790ec938087c9047bc7b1b4f30a65406cd (patch)
tree40b6d35e57e82258dbf1c6cafe8469b8b16dc375 /arch/s390
parentb5510d9b68c33964abd938148f407ad3789e369f (diff)
s390/fpu: add static FPU save area for init_task
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>
Diffstat (limited to 'arch/s390')
-rw-r--r--arch/s390/include/asm/processor.h2
-rw-r--r--arch/s390/kernel/entry.S4
-rw-r--r--arch/s390/kernel/process.c4
3 files changed, 6 insertions, 4 deletions
diff --git a/arch/s390/include/asm/processor.h b/arch/s390/include/asm/processor.h
index 085fb0d3c54e..5900877bb19c 100644
--- a/arch/s390/include/asm/processor.h
+++ b/arch/s390/include/asm/processor.h
@@ -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, \
}
/*
diff --git a/arch/s390/kernel/entry.S b/arch/s390/kernel/entry.S
index b78babf9a417..3f23185c9173 100644
--- a/arch/s390/kernel/entry.S
+++ b/arch/s390/kernel/entry.S
@@ -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)
diff --git a/arch/s390/kernel/process.c b/arch/s390/kernel/process.c
index b63787156a19..cd5568608744 100644
--- a/arch/s390/kernel/process.c
+++ b/arch/s390/kernel/process.c
@@ -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