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/*
* Copyright 2015, Cyril Bur, IBM Corp.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#include "basic_asm.h"
#include "vmx_asm.h"
# Should be safe from C, only touches r4, r5 and v0,v1,v2
FUNC_START(check_vmx)
PUSH_BASIC_STACK(32)
mr r4,r3
li r3,1 # assume a bad result
li r5,0
lvx v0,r5,r4
vcmpequd. v1,v0,v20
vmr v2,v1
addi r5,r5,16
lvx v0,r5,r4
vcmpequd. v1,v0,v21
vand v2,v2,v1
addi r5,r5,16
lvx v0,r5,r4
vcmpequd. v1,v0,v22
vand v2,v2,v1
addi r5,r5,16
lvx v0,r5,r4
vcmpequd. v1,v0,v23
vand v2,v2,v1
addi r5,r5,16
lvx v0,r5,r4
vcmpequd. v1,v0,v24
vand v2,v2,v1
addi r5,r5,16
lvx v0,r5,r4
vcmpequd. v1,v0,v25
vand v2,v2,v1
addi r5,r5,16
lvx v0,r5,r4
vcmpequd. v1,v0,v26
vand v2,v2,v1
addi r5,r5,16
lvx v0,r5,r4
vcmpequd. v1,v0,v27
vand v2,v2,v1
addi r5,r5,16
lvx v0,r5,r4
vcmpequd. v1,v0,v28
vand v2,v2,v1
addi r5,r5,16
lvx v0,r5,r4
vcmpequd. v1,v0,v29
vand v2,v2,v1
addi r5,r5,16
lvx v0,r5,r4
vcmpequd. v1,v0,v30
vand v2,v2,v1
addi r5,r5,16
lvx v0,r5,r4
vcmpequd. v1,v0,v31
vand v2,v2,v1
li r5,STACK_FRAME_LOCAL(0,0)
stvx v2,r5,sp
ldx r0,r5,sp
cmpdi r0,0xffffffffffffffff
bne 1f
li r3,0
1: POP_BASIC_STACK(32)
blr
FUNC_END(check_vmx)
# Safe from C
FUNC_START(test_vmx)
# r3 holds pointer to where to put the result of fork
# r4 holds pointer to the pid
# v20-v31 are non-volatile
PUSH_BASIC_STACK(512)
std r3,STACK_FRAME_PARAM(0)(sp) # Address of varray
std r4,STACK_FRAME_PARAM(1)(sp) # address of pid
PUSH_VMX(STACK_FRAME_LOCAL(2,0),r4)
bl load_vmx
nop
li r0,__NR_fork
sc
# Pass the result of fork back to the caller
ld r9,STACK_FRAME_PARAM(1)(sp)
std r3,0(r9)
ld r3,STACK_FRAME_PARAM(0)(sp)
bl check_vmx
nop
POP_VMX(STACK_FRAME_LOCAL(2,0),r4)
POP_BASIC_STACK(512)
blr
FUNC_END(test_vmx)
# int preempt_vmx(vector int *varray, int *threads_starting, int *running)
# On starting will (atomically) decrement threads_starting as a signal that
# the VMX have been loaded with varray. Will proceed to check the validity of
# the VMX registers while running is not zero.
FUNC_START(preempt_vmx)
PUSH_BASIC_STACK(512)
std r3,STACK_FRAME_PARAM(0)(sp) # vector int *varray
std r4,STACK_FRAME_PARAM(1)(sp) # int *threads_starting
std r5,STACK_FRAME_PARAM(2)(sp) # int *running
# VMX need to write to 16 byte aligned addresses, skip STACK_FRAME_LOCAL(3,0)
PUSH_VMX(STACK_FRAME_LOCAL(4,0),r4)
bl load_vmx
nop
sync
# Atomic DEC
ld r3,STACK_FRAME_PARAM(1)(sp)
1: lwarx r4,0,r3
addi r4,r4,-1
stwcx. r4,0,r3
bne- 1b
2: ld r3,STACK_FRAME_PARAM(0)(sp)
bl check_vmx
nop
cmpdi r3,0
bne 3f
ld r4,STACK_FRAME_PARAM(2)(sp)
ld r5,0(r4)
cmpwi r5,0
bne 2b
3: POP_VMX(STACK_FRAME_LOCAL(4,0),r4)
POP_BASIC_STACK(512)
blr
FUNC_END(preempt_vmx)
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