linux/arch/arm64/include/asm/fpsimd.h
Dave Martin 624835abf9 arm64/sve: Clarify vq map semantics
Currently the meanings of sve_vq_map and the ancillary helpers
__bit_to_vq() and __vq_to_bit() are not clearly explained.

This patch makes the explanatory comment clearer, and removes the
duplicate comment from fpsimd.h.

The WARN_ON() currently present in __bit_to_vq() confuses the
intended use of this helper.  Since these are low-level helpers not
intended for general-purpose use anyway, it is better not to make
guesses about how these functions will be used: rather, this patch
removes the WARN_ON() and relies on callers to use the helpers
sensibly.

Suggested-by: Andrew Jones <drjones@redhat.com>
Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Reviewed-by: Andrew Jones <drjones@redhat.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2019-04-18 17:14:01 +01:00

187 lines
5.4 KiB
C

/*
* Copyright (C) 2012 ARM Ltd.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#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>
#if defined(__KERNEL__) && defined(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_save(void);
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_task_to_cpu(void);
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_flush_cpu_state(void);
extern void sve_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->sve_vl);
}
extern void sve_save_state(void *state, u32 *pfpsr);
extern void sve_load_state(void const *state, u32 const *pfpsr,
unsigned long vq_minus_1);
extern unsigned int sve_get_vl(void);
struct arm64_cpu_capabilities;
extern void sve_kernel_enable(const struct arm64_cpu_capabilities *__unused);
extern u64 read_zcr_features(void);
extern int __ro_after_init sve_max_vl;
extern int __ro_after_init sve_max_virtualisable_vl;
extern __ro_after_init DECLARE_BITMAP(sve_vq_map, SVE_VQ_MAX);
/*
* 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;
}
/* Ensure vq >= SVE_VQ_MIN && vq <= SVE_VQ_MAX before calling this function */
static inline bool sve_vq_available(unsigned int vq)
{
return test_bit(__vq_to_bit(vq), sve_vq_map);
}
#ifdef CONFIG_ARM64_SVE
extern size_t sve_state_size(struct task_struct const *task);
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);
}
/*
* Probing and setup functions.
* Calls to these functions must be serialised with one another.
*/
extern void __init sve_init_vq_map(void);
extern void sve_update_vq_map(void);
extern int sve_verify_vq_map(void);
extern void __init sve_setup(void);
#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_set_current_vl(unsigned long arg)
{
return -EINVAL;
}
static inline int sve_get_current_vl(void)
{
return -EINVAL;
}
static inline void sve_user_disable(void) { BUILD_BUG(); }
static inline void sve_user_enable(void) { BUILD_BUG(); }
static inline void sve_init_vq_map(void) { }
static inline void sve_update_vq_map(void) { }
static inline int sve_verify_vq_map(void) { 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