arm64: CPU support

This patch adds AArch64 CPU specific functionality. It assumes that the
implementation is generic to AArch64 and does not require specific
identification. Different CPU implementations may require the setting of
various ACTLR_EL1 bits but such information is not currently available
and it should ideally be pushed to firmware.

Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Tony Lindgren <tony@atomide.com>
Acked-by: Nicolas Pitre <nico@linaro.org>
Acked-by: Olof Johansson <olof@lixom.net>
Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com>

1 files changed, 175 insertions, 0 deletions

diff --git a/arch/arm64/include/asm/processor.h b/arch/arm64/include/asm/processor.h
new file mode 100644
index 00000000000..39a208a392f
--- /dev/null
+++ b/arch/arm64/include/asm/processor.h
@@ -0,0 +1,175 @@
+/*
+ * 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/fpsimd.h>
+#include <asm/hw_breakpoint.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 */
+#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;
+	struct fpsimd_state	fpsimd_state;
+	unsigned long		fault_address;	/* fault info */
+	struct debug_info	debug;		/* debugging */
+};
+
+#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)
+{
+	unsigned long *stack = (unsigned long *)sp;
+
+	start_thread_common(regs, pc);
+	regs->pstate = PSR_MODE_EL0t;
+	regs->sp = sp;
+	regs->regs[2] = stack[2];	/* x2 (envp) */
+	regs->regs[1] = stack[1];	/* x1 (argv) */
+	regs->regs[0] = stack[0];	/* x0 (argc) */
+}
+
+#ifdef CONFIG_COMPAT
+static inline void compat_start_thread(struct pt_regs *regs, unsigned long pc,
+				       unsigned long sp)
+{
+	unsigned int *stack = (unsigned int *)sp;
+
+	start_thread_common(regs, pc);
+	regs->pstate = COMPAT_PSR_MODE_USR;
+	if (pc & 1)
+		regs->pstate |= COMPAT_PSR_T_BIT;
+	regs->compat_sp = sp;
+	regs->regs[2] = stack[2];	/* x2 (envp) */
+	regs->regs[1] = stack[1];	/* x1 (argv) */
+	regs->regs[0] = stack[0];	/* x0 (argc) */
+}
+#endif
+
+/* Forward declaration, a strange C thing */
+struct task_struct;
+
+/* Free all resources held by a thread. */
+extern void release_thread(struct task_struct *);
+
+/* Prepare to copy thread state - unlazy all lazy status */
+#define prepare_to_copy(tsk)	do { } while (0)
+
+unsigned long get_wchan(struct task_struct *p);
+
+#define cpu_relax()			barrier()
+
+/* Thread switching */
+extern struct task_struct *cpu_switch_to(struct task_struct *prev,
+					 struct task_struct *next);
+
+/*
+ * Create a new kernel thread
+ */
+extern int kernel_thread(int (*fn)(void *), void *arg, unsigned long flags);
+
+#define task_pt_regs(p) \
+	((struct pt_regs *)(THREAD_START_SP + task_stack_page(p)) - 1)
+
+#define KSTK_EIP(tsk)	task_pt_regs(tsk)->pc
+#define KSTK_ESP(tsk)	task_pt_regs(tsk)->sp
+
+/*
+ * 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 *x)
+{
+	prefetchw(x);
+}
+
+#define HAVE_ARCH_PICK_MMAP_LAYOUT
+
+#endif
+
+#endif /* __ASM_PROCESSOR_H */