linux/arch/arm64/include/asm/processor.h
Will Deacon cd5e10bdf3 arm64: prefetch: don't provide spin_lock_prefetch with LSE
The LSE atomics rely on us not dirtying data at L1 if we can avoid it,
otherwise many of the potential scalability benefits are lost.

This patch replaces spin_lock_prefetch with a nop when the LSE atomics
are in use, so that users don't shoot themselves in the foot by causing
needless coherence traffic at L1.

Signed-off-by: Will Deacon <will.deacon@arm.com>
Tested-by: Andrew Pinski <apinski@cavium.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2016-02-16 15:12:32 +00:00

195 lines
4.7 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
/*
* 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/pgtable-hwdef.h>
#include <asm/ptrace.h>
#include <asm/types.h>
#ifdef __KERNEL__
#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)
#endif /* __KERNEL__ */
struct debug_info {
/* 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];
};
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;
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
#define INIT_THREAD { }
static inline void start_thread_common(struct pt_regs *regs, unsigned long pc)
{
memset(regs, 0, sizeof(*regs));
regs->syscallno = ~0UL;
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");
}
#define cpu_relax_lowlatency() cpu_relax()
/* 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_START_SP + 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
void cpu_enable_pan(void *__unused);
#endif /* __ASM_PROCESSOR_H */