linux/arch/arm64/kernel/entry-fpsimd.S
Julien Grall 9c4b4c701e arm64/sve: Implement a helper to load SVE registers from FPSIMD state
In a follow-up patch, we may save the FPSIMD rather than the full SVE
state when the state has to be zeroed on return to userspace (e.g
during a syscall).

Introduce an helper to load SVE vectors from FPSIMD state and zero the rest
of SVE registers.

Signed-off-by: Julien Grall <julien.grall@arm.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Dave Martin <Dave.Martin@arm.com>
Link: https://lore.kernel.org/r/20200828181155.17745-7-broonie@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
2020-09-21 18:06:33 +01:00

75 lines
1.4 KiB
ArmAsm

/* SPDX-License-Identifier: GPL-2.0-only */
/*
* FP/SIMD state saving and restoring
*
* Copyright (C) 2012 ARM Ltd.
* Author: Catalin Marinas <catalin.marinas@arm.com>
*/
#include <linux/linkage.h>
#include <asm/assembler.h>
#include <asm/fpsimdmacros.h>
/*
* Save the FP registers.
*
* x0 - pointer to struct fpsimd_state
*/
SYM_FUNC_START(fpsimd_save_state)
fpsimd_save x0, 8
ret
SYM_FUNC_END(fpsimd_save_state)
/*
* Load the FP registers.
*
* x0 - pointer to struct fpsimd_state
*/
SYM_FUNC_START(fpsimd_load_state)
fpsimd_restore x0, 8
ret
SYM_FUNC_END(fpsimd_load_state)
#ifdef CONFIG_ARM64_SVE
SYM_FUNC_START(sve_save_state)
sve_save 0, x1, 2
ret
SYM_FUNC_END(sve_save_state)
SYM_FUNC_START(sve_load_state)
sve_load 0, x1, x2, 3, x4
ret
SYM_FUNC_END(sve_load_state)
SYM_FUNC_START(sve_get_vl)
_sve_rdvl 0, 1
ret
SYM_FUNC_END(sve_get_vl)
/*
* Load SVE state from FPSIMD state.
*
* x0 = pointer to struct fpsimd_state
* x1 = VQ - 1
*
* Each SVE vector will be loaded with the first 128-bits taken from FPSIMD
* and the rest zeroed. All the other SVE registers will be zeroed.
*/
SYM_FUNC_START(sve_load_from_fpsimd_state)
sve_load_vq x1, x2, x3
fpsimd_restore x0, 8
_for n, 0, 15, _sve_pfalse \n
_sve_wrffr 0
ret
SYM_FUNC_END(sve_load_from_fpsimd_state)
/* Zero all SVE registers but the first 128-bits of each vector */
SYM_FUNC_START(sve_flush_live)
sve_flush
ret
SYM_FUNC_END(sve_flush_live)
#endif /* CONFIG_ARM64_SVE */