tools/testing/selftests/arm64/fp/fpsimd-test.S

Source file repositories/reference/linux-study-clean/tools/testing/selftests/arm64/fp/fpsimd-test.S

File Facts

System
Linux kernel
Corpus path
tools/testing/selftests/arm64/fp/fpsimd-test.S
Extension
.S
Size
5793 bytes
Lines
333
Domain
Support Tooling And Documentation
Bucket
tools
Inferred role
Support Tooling And Documentation: tools
Status
atlas-only

Why This File Exists

Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.

Dependency Surface

Detected Declarations

Annotated Snippet

// SPDX-License-Identifier: GPL-2.0-only
// Copyright (C) 2015-2019 ARM Limited.
// Original author: Dave Martin <Dave.Martin@arm.com>
//
// Simple FPSIMD context switch test
// Repeatedly writes unique test patterns into each FPSIMD register
// and reads them back to verify integrity.
//
// for x in `seq 1 NR_CPUS`; do fpsimd-test & pids=$pids\ $! ; done
// (leave it running for as long as you want...)
// kill $pids

#include <asm/unistd.h>
#include "assembler.h"
#include "asm-offsets.h"

#define NVR	32
#define MAXVL_B	(128 / 8)

.macro _vldr Vn:req, Xt:req
	ld1	{v\Vn\().2d}, [x\Xt]
.endm

.macro _vstr Vn:req, Xt:req
	st1	{v\Vn\().2d}, [x\Xt]
.endm

// Generate accessor functions to read/write programmatically selected
// FPSIMD registers.
// x0 is the register index to access
// x1 is the memory address to read from (getv,setp) or store to (setv,setp)
// All clobber x0-x2
define_accessor setv, NVR, _vldr
define_accessor getv, NVR, _vstr

// Declare some storate space to shadow the SVE register contents:
.pushsection .text
.data
.align 4
vref:
	.space	MAXVL_B * NVR
scratch:
	.space	MAXVL_B
.popsection

// Generate a test pattern for storage in SVE registers
// x0: pid	(16 bits)
// x1: register number (6 bits)
// x2: generation (4 bits)
function pattern
	orr	w1, w0, w1, lsl #16
	orr	w2, w1, w2, lsl #28

	ldr	x0, =scratch
	mov	w1, #MAXVL_B / 4

0:	str	w2, [x0], #4
	add	w2, w2, #(1 << 22)
	subs	w1, w1, #1
	bne	0b

	ret
endfunction

// Get the address of shadow data for FPSIMD V-register V<xn>
.macro _adrv xd, xn, nrtmp
	ldr	\xd, =vref
	mov	x\nrtmp, #16
	madd	\xd, x\nrtmp, \xn, \xd
.endm

Annotation

Implementation Notes