linux-stable/arch/arm64/kernel/entry-fpsimd.S
Mark Brown b42990d3bf arm64/sme: Identify supported SME vector lengths at boot
The vector lengths used for SME are controlled through a similar set of
registers to those for SVE and enumerated using a similar algorithm with
some slight differences due to the fact that unlike SVE there are no
restrictions on which combinations of vector lengths can be supported
nor any mandatory vector lengths which must be implemented.  Add a new
vector type and implement support for enumerating it.

One slightly awkward feature is that we need to read the current vector
length using a different instruction (or enter streaming mode which
would have the same issue and be higher cost).  Rather than add an ops
structure we add special cases directly in the otherwise generic
vec_probe_vqs() function, this is a bit inelegant but it's the only
place where this is an issue.

Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20220419112247.711548-10-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2022-04-22 18:50:51 +01:00

98 lines
1.8 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
/*
* Save the SVE state
*
* x0 - pointer to buffer for state
* x1 - pointer to storage for FPSR
* x2 - Save FFR if non-zero
*/
SYM_FUNC_START(sve_save_state)
sve_save 0, x1, x2, 3
ret
SYM_FUNC_END(sve_save_state)
/*
* Load the SVE state
*
* x0 - pointer to buffer for state
* x1 - pointer to storage for FPSR
* x2 - Restore FFR if non-zero
*/
SYM_FUNC_START(sve_load_state)
sve_load 0, x1, x2, 4
ret
SYM_FUNC_END(sve_load_state)
SYM_FUNC_START(sve_get_vl)
_sve_rdvl 0, 1
ret
SYM_FUNC_END(sve_get_vl)
SYM_FUNC_START(sve_set_vq)
sve_load_vq x0, x1, x2
ret
SYM_FUNC_END(sve_set_vq)
/*
* Zero all SVE registers but the first 128-bits of each vector
*
* VQ must already be configured by caller, any further updates of VQ
* will need to ensure that the register state remains valid.
*
* x0 = include FFR?
* x1 = VQ - 1
*/
SYM_FUNC_START(sve_flush_live)
cbz x1, 1f // A VQ-1 of 0 is 128 bits so no extra Z state
sve_flush_z
1: sve_flush_p
tbz x0, #0, 2f
sve_flush_ffr
2: ret
SYM_FUNC_END(sve_flush_live)
#endif /* CONFIG_ARM64_SVE */
#ifdef CONFIG_ARM64_SME
SYM_FUNC_START(sme_get_vl)
_sme_rdsvl 0, 1
ret
SYM_FUNC_END(sme_get_vl)
#endif /* CONFIG_ARM64_SME */