xref: /linux/arch/arm64/include/asm/fpsimd.h

/* SPDX-License-Identifier: GPL-2.0-only */
/*
 * Copyright (C) 2012 ARM Ltd.
 */
#ifndef __ASM_FP_H
#define __ASM_FP_H

#include <asm/errno.h>
#include <asm/ptrace.h>
#include <asm/processor.h>
#include <asm/sigcontext.h>
#include <asm/sysreg.h>

#ifndef __ASSEMBLY__

#include <linux/bitmap.h>
#include <linux/build_bug.h>
#include <linux/bug.h>
#include <linux/cache.h>
#include <linux/init.h>
#include <linux/stddef.h>
#include <linux/types.h>

#ifdef CONFIG_COMPAT
/* Masks for extracting the FPSR and FPCR from the FPSCR */
#define VFP_FPSCR_STAT_MASK	0xf800009f
#define VFP_FPSCR_CTRL_MASK	0x07f79f00
/*
 * The VFP state has 32x64-bit registers and a single 32-bit
 * control/status register.
 */
#define VFP_STATE_SIZE		((32 * 8) + 4)
#endif

struct task_struct;

extern void fpsimd_save_state(struct user_fpsimd_state *state);
extern void fpsimd_load_state(struct user_fpsimd_state *state);

extern void fpsimd_thread_switch(struct task_struct *next);
extern void fpsimd_flush_thread(void);

extern void fpsimd_signal_preserve_current_state(void);
extern void fpsimd_preserve_current_state(void);
extern void fpsimd_restore_current_state(void);
extern void fpsimd_update_current_state(struct user_fpsimd_state const *state);

extern void fpsimd_bind_state_to_cpu(struct user_fpsimd_state *state,
				     void *sve_state, unsigned int sve_vl);

extern void fpsimd_flush_task_state(struct task_struct *target);
extern void fpsimd_save_and_flush_cpu_state(void);

/* Maximum VL that SVE VL-agnostic software can transparently support */
#define SVE_VL_ARCH_MAX 0x100

/* Offset of FFR in the SVE register dump */
static inline size_t sve_ffr_offset(int vl)
{
	return SVE_SIG_FFR_OFFSET(sve_vq_from_vl(vl)) - SVE_SIG_REGS_OFFSET;
}

static inline void *sve_pffr(struct thread_struct *thread)
{
	return (char *)thread->sve_state + sve_ffr_offset(thread_get_sve_vl(thread));
}

extern void sve_save_state(void *state, u32 *pfpsr, int save_ffr);
extern void sve_load_state(void const *state, u32 const *pfpsr,
			   int restore_ffr);
extern void sve_flush_live(bool flush_ffr, unsigned long vq_minus_1);
extern unsigned int sve_get_vl(void);
extern void sve_set_vq(unsigned long vq_minus_1);

struct arm64_cpu_capabilities;
extern void sve_kernel_enable(const struct arm64_cpu_capabilities *__unused);

extern u64 read_zcr_features(void);

/*
 * Helpers to translate bit indices in sve_vq_map to VQ values (and
 * vice versa).  This allows find_next_bit() to be used to find the
 * _maximum_ VQ not exceeding a certain value.
 */
static inline unsigned int __vq_to_bit(unsigned int vq)
{
	return SVE_VQ_MAX - vq;
}

static inline unsigned int __bit_to_vq(unsigned int bit)
{
	return SVE_VQ_MAX - bit;
}


struct vl_info {
	enum vec_type type;
	const char *name;		/* For display purposes */

	/* Minimum supported vector length across all CPUs */
	int min_vl;

	/* Maximum supported vector length across all CPUs */
	int max_vl;
	int max_virtualisable_vl;

	/*
	 * Set of available vector lengths,
	 * where length vq encoded as bit __vq_to_bit(vq):
	 */
	DECLARE_BITMAP(vq_map, SVE_VQ_MAX);

	/* Set of vector lengths present on at least one cpu: */
	DECLARE_BITMAP(vq_partial_map, SVE_VQ_MAX);
};

#ifdef CONFIG_ARM64_SVE

extern void sve_alloc(struct task_struct *task);
extern void fpsimd_release_task(struct task_struct *task);
extern void fpsimd_sync_to_sve(struct task_struct *task);
extern void sve_sync_to_fpsimd(struct task_struct *task);
extern void sve_sync_from_fpsimd_zeropad(struct task_struct *task);

extern int sve_set_vector_length(struct task_struct *task,
				 unsigned long vl, unsigned long flags);

extern int sve_set_current_vl(unsigned long arg);
extern int sve_get_current_vl(void);

static inline void sve_user_disable(void)
{
	sysreg_clear_set(cpacr_el1, CPACR_EL1_ZEN_EL0EN, 0);
}

static inline void sve_user_enable(void)
{
	sysreg_clear_set(cpacr_el1, 0, CPACR_EL1_ZEN_EL0EN);
}

#define sve_cond_update_zcr_vq(val, reg)		\
	do {						\
		u64 __zcr = read_sysreg_s((reg));	\
		u64 __new = __zcr & ~ZCR_ELx_LEN_MASK;	\
		__new |= (val) & ZCR_ELx_LEN_MASK;	\
		if (__zcr != __new)			\
			write_sysreg_s(__new, (reg));	\
	} while (0)

/*
 * Probing and setup functions.
 * Calls to these functions must be serialised with one another.
 */
enum vec_type;

extern void __init vec_init_vq_map(enum vec_type type);
extern void vec_update_vq_map(enum vec_type type);
extern int vec_verify_vq_map(enum vec_type type);
extern void __init sve_setup(void);

extern __ro_after_init struct vl_info vl_info[ARM64_VEC_MAX];

static inline void write_vl(enum vec_type type, u64 val)
{
	u64 tmp;

	switch (type) {
#ifdef CONFIG_ARM64_SVE
	case ARM64_VEC_SVE:
		tmp = read_sysreg_s(SYS_ZCR_EL1) & ~ZCR_ELx_LEN_MASK;
		write_sysreg_s(tmp | val, SYS_ZCR_EL1);
		break;
#endif
	default:
		WARN_ON_ONCE(1);
		break;
	}
}

static inline int vec_max_vl(enum vec_type type)
{
	return vl_info[type].max_vl;
}

static inline int vec_max_virtualisable_vl(enum vec_type type)
{
	return vl_info[type].max_virtualisable_vl;
}

static inline int sve_max_vl(void)
{
	return vec_max_vl(ARM64_VEC_SVE);
}

static inline int sve_max_virtualisable_vl(void)
{
	return vec_max_virtualisable_vl(ARM64_VEC_SVE);
}

/* Ensure vq >= SVE_VQ_MIN && vq <= SVE_VQ_MAX before calling this function */
static inline bool vq_available(enum vec_type type, unsigned int vq)
{
	return test_bit(__vq_to_bit(vq), vl_info[type].vq_map);
}

static inline bool sve_vq_available(unsigned int vq)
{
	return vq_available(ARM64_VEC_SVE, vq);
}

#else /* ! CONFIG_ARM64_SVE */

static inline void sve_alloc(struct task_struct *task) { }
static inline void fpsimd_release_task(struct task_struct *task) { }
static inline void sve_sync_to_fpsimd(struct task_struct *task) { }
static inline void sve_sync_from_fpsimd_zeropad(struct task_struct *task) { }

static inline int sve_max_virtualisable_vl(void)
{
	return 0;
}

static inline int sve_set_current_vl(unsigned long arg)
{
	return -EINVAL;
}

static inline int sve_get_current_vl(void)
{
	return -EINVAL;
}

static inline int sve_max_vl(void)
{
	return -EINVAL;
}

static inline bool sve_vq_available(unsigned int vq) { return false; }

static inline void sve_user_disable(void) { BUILD_BUG(); }
static inline void sve_user_enable(void) { BUILD_BUG(); }

#define sve_cond_update_zcr_vq(val, reg) do { } while (0)

static inline void vec_init_vq_map(enum vec_type t) { }
static inline void vec_update_vq_map(enum vec_type t) { }
static inline int vec_verify_vq_map(enum vec_type t) { return 0; }
static inline void sve_setup(void) { }

#endif /* ! CONFIG_ARM64_SVE */

/* For use by EFI runtime services calls only */
extern void __efi_fpsimd_begin(void);
extern void __efi_fpsimd_end(void);

#endif

#endif