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linux-next/tools/testing/selftests/powerpc/math/vsx_asm.S
Cyril Bur 65ca668f58 selftests/powerpc: Check for VSX preservation across userspace preemption
Ensure the kernel correctly switches VSX registers correctly. VSX
registers are all volatile, and despite the kernel preserving VSX
across syscalls, it doesn't have to. Test that during interrupts and
timeslices ending the VSX regs remain the same.

Signed-off-by: Cyril Bur <cyrilbur@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-10-04 20:10:09 +11:00

62 lines
1.5 KiB
ArmAsm

/*
* 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 "../vsx_asm.h"
#long check_vsx(vector int *r3);
#This function wraps storeing VSX regs to the end of an array and a
#call to a comparison function in C which boils down to a memcmp()
FUNC_START(check_vsx)
PUSH_BASIC_STACK(32)
std r3,STACK_FRAME_PARAM(0)(sp)
addi r3, r3, 16 * 12 #Second half of array
bl store_vsx
ld r3,STACK_FRAME_PARAM(0)(sp)
bl vsx_memcmp
POP_BASIC_STACK(32)
blr
FUNC_END(check_vsx)
# 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_vsx)
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
bl load_vsx
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_vsx
nop
cmpdi r3,0
bne 3f
ld r4,STACK_FRAME_PARAM(2)(sp)
ld r5,0(r4)
cmpwi r5,0
bne 2b
3: POP_BASIC_STACK(512)
blr
FUNC_END(preempt_vsx)