linux/arch/arm64/include/asm/processor.h
Dave Martin 2d2123bc7c arm64/sve: Add prctl controls for userspace vector length management
This patch adds two arm64-specific prctls, to permit userspace to
control its vector length:

 * PR_SVE_SET_VL: set the thread's SVE vector length and vector
   length inheritance mode.

 * PR_SVE_GET_VL: get the same information.

Although these prctls resemble instruction set features in the SVE
architecture, they provide additional control: the vector length
inheritance mode is Linux-specific and nothing to do with the
architecture, and the architecture does not permit EL0 to set its
own vector length directly.  Both can be used in portable tools
without requiring the use of SVE instructions.

Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Alex Bennée <alex.bennee@linaro.org>
[will: Fixed up prctl constants to avoid clash with PDEATHSIG]
Signed-off-by: Will Deacon <will.deacon@arm.com>
2017-11-03 15:24:19 +00:00

226 lines
5.7 KiB
C

/*
* Based on arch/arm/include/asm/processor.h
*
* Copyright (C) 1995-1999 Russell King
* 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_PROCESSOR_H
#define __ASM_PROCESSOR_H
#define TASK_SIZE_64 (UL(1) << VA_BITS)
#ifndef __ASSEMBLY__
/*
* Default implementation of macro that returns current
* instruction pointer ("program counter").
*/
#define current_text_addr() ({ __label__ _l; _l: &&_l;})
#ifdef __KERNEL__
#include <linux/string.h>
#include <asm/alternative.h>
#include <asm/fpsimd.h>
#include <asm/hw_breakpoint.h>
#include <asm/lse.h>
#include <asm/pgtable-hwdef.h>
#include <asm/ptrace.h>
#include <asm/types.h>
/*
* TASK_SIZE - the maximum size of a user space task.
* TASK_UNMAPPED_BASE - the lower boundary of the mmap VM area.
*/
#ifdef CONFIG_COMPAT
#define TASK_SIZE_32 UL(0x100000000)
#define TASK_SIZE (test_thread_flag(TIF_32BIT) ? \
TASK_SIZE_32 : TASK_SIZE_64)
#define TASK_SIZE_OF(tsk) (test_tsk_thread_flag(tsk, TIF_32BIT) ? \
TASK_SIZE_32 : TASK_SIZE_64)
#else
#define TASK_SIZE TASK_SIZE_64
#endif /* CONFIG_COMPAT */
#define TASK_UNMAPPED_BASE (PAGE_ALIGN(TASK_SIZE / 4))
#define STACK_TOP_MAX TASK_SIZE_64
#ifdef CONFIG_COMPAT
#define AARCH32_VECTORS_BASE 0xffff0000
#define STACK_TOP (test_thread_flag(TIF_32BIT) ? \
AARCH32_VECTORS_BASE : STACK_TOP_MAX)
#else
#define STACK_TOP STACK_TOP_MAX
#endif /* CONFIG_COMPAT */
extern phys_addr_t arm64_dma_phys_limit;
#define ARCH_LOW_ADDRESS_LIMIT (arm64_dma_phys_limit - 1)
struct debug_info {
#ifdef CONFIG_HAVE_HW_BREAKPOINT
/* Have we suspended stepping by a debugger? */
int suspended_step;
/* Allow breakpoints and watchpoints to be disabled for this thread. */
int bps_disabled;
int wps_disabled;
/* Hardware breakpoints pinned to this task. */
struct perf_event *hbp_break[ARM_MAX_BRP];
struct perf_event *hbp_watch[ARM_MAX_WRP];
#endif
};
struct cpu_context {
unsigned long x19;
unsigned long x20;
unsigned long x21;
unsigned long x22;
unsigned long x23;
unsigned long x24;
unsigned long x25;
unsigned long x26;
unsigned long x27;
unsigned long x28;
unsigned long fp;
unsigned long sp;
unsigned long pc;
};
struct thread_struct {
struct cpu_context cpu_context; /* cpu context */
unsigned long tp_value; /* TLS register */
#ifdef CONFIG_COMPAT
unsigned long tp2_value;
#endif
struct fpsimd_state fpsimd_state;
void *sve_state; /* SVE registers, if any */
unsigned int sve_vl; /* SVE vector length */
unsigned int sve_vl_onexec; /* SVE vl after next exec */
unsigned long fault_address; /* fault info */
unsigned long fault_code; /* ESR_EL1 value */
struct debug_info debug; /* debugging */
};
#ifdef CONFIG_COMPAT
#define task_user_tls(t) \
({ \
unsigned long *__tls; \
if (is_compat_thread(task_thread_info(t))) \
__tls = &(t)->thread.tp2_value; \
else \
__tls = &(t)->thread.tp_value; \
__tls; \
})
#else
#define task_user_tls(t) (&(t)->thread.tp_value)
#endif
/* Sync TPIDR_EL0 back to thread_struct for current */
void tls_preserve_current_state(void);
#define INIT_THREAD { }
static inline void start_thread_common(struct pt_regs *regs, unsigned long pc)
{
memset(regs, 0, sizeof(*regs));
forget_syscall(regs);
regs->pc = pc;
}
static inline void start_thread(struct pt_regs *regs, unsigned long pc,
unsigned long sp)
{
start_thread_common(regs, pc);
regs->pstate = PSR_MODE_EL0t;
regs->sp = sp;
}
#ifdef CONFIG_COMPAT
static inline void compat_start_thread(struct pt_regs *regs, unsigned long pc,
unsigned long sp)
{
start_thread_common(regs, pc);
regs->pstate = COMPAT_PSR_MODE_USR;
if (pc & 1)
regs->pstate |= COMPAT_PSR_T_BIT;
#ifdef __AARCH64EB__
regs->pstate |= COMPAT_PSR_E_BIT;
#endif
regs->compat_sp = sp;
}
#endif
/* Forward declaration, a strange C thing */
struct task_struct;
/* Free all resources held by a thread. */
extern void release_thread(struct task_struct *);
unsigned long get_wchan(struct task_struct *p);
static inline void cpu_relax(void)
{
asm volatile("yield" ::: "memory");
}
/* Thread switching */
extern struct task_struct *cpu_switch_to(struct task_struct *prev,
struct task_struct *next);
#define task_pt_regs(p) \
((struct pt_regs *)(THREAD_SIZE + task_stack_page(p)) - 1)
#define KSTK_EIP(tsk) ((unsigned long)task_pt_regs(tsk)->pc)
#define KSTK_ESP(tsk) user_stack_pointer(task_pt_regs(tsk))
/*
* Prefetching support
*/
#define ARCH_HAS_PREFETCH
static inline void prefetch(const void *ptr)
{
asm volatile("prfm pldl1keep, %a0\n" : : "p" (ptr));
}
#define ARCH_HAS_PREFETCHW
static inline void prefetchw(const void *ptr)
{
asm volatile("prfm pstl1keep, %a0\n" : : "p" (ptr));
}
#define ARCH_HAS_SPINLOCK_PREFETCH
static inline void spin_lock_prefetch(const void *ptr)
{
asm volatile(ARM64_LSE_ATOMIC_INSN(
"prfm pstl1strm, %a0",
"nop") : : "p" (ptr));
}
#define HAVE_ARCH_PICK_MMAP_LAYOUT
#endif
int cpu_enable_pan(void *__unused);
int cpu_enable_cache_maint_trap(void *__unused);
/* Userspace interface for PR_SVE_{SET,GET}_VL prctl()s: */
#define SVE_SET_VL(arg) sve_set_current_vl(arg)
#define SVE_GET_VL() sve_get_current_vl()
#endif /* __ASSEMBLY__ */
#endif /* __ASM_PROCESSOR_H */