arch/arm/include/asm/processor.h

/* SPDX-License-Identifier: GPL-2.0-only */
/*
 *  arch/arm/include/asm/processor.h
 *
 *  Copyright (C) 1995-1999 Russell King
 */

#ifndef __ASM_ARM_PROCESSOR_H
#define __ASM_ARM_PROCESSOR_H

#ifdef __KERNEL__

#include <asm/hw_breakpoint.h>
#include <asm/ptrace.h>
#include <asm/types.h>
#include <asm/unified.h>

#ifdef __KERNEL__
#define STACK_TOP	((current->personality & ADDR_LIMIT_32BIT) ? \
			 TASK_SIZE : TASK_SIZE_26)
#define STACK_TOP_MAX	TASK_SIZE
#endif

struct debug_info {
#ifdef CONFIG_HAVE_HW_BREAKPOINT
	struct perf_event	*hbp[ARM_MAX_HBP_SLOTS];
#endif
};

struct thread_struct {
							/* fault info	  */
	unsigned long		address;
	unsigned long		trap_no;
	unsigned long		error_code;
							/* debugging	  */
	struct debug_info	debug;
};

/*
 * Everything usercopied to/from thread_struct is statically-sized, so
 * no hardened usercopy whitelist is needed.
 */
static inline void arch_thread_struct_whitelist(unsigned long *offset,
						unsigned long *size)
{
	*offset = *size = 0;
}

#define INIT_THREAD  {	}

#define start_thread(regs,pc,sp)					\
({									\
	unsigned long r7, r8, r9;					\
									\
	if (IS_ENABLED(CONFIG_BINFMT_ELF_FDPIC)) {			\
		r7 = regs->ARM_r7;					\
		r8 = regs->ARM_r8;					\
		r9 = regs->ARM_r9;					\
	}								\
	memset(regs->uregs, 0, sizeof(regs->uregs));			\
	if (IS_ENABLED(CONFIG_BINFMT_ELF_FDPIC) &&			\
	    current->personality & FDPIC_FUNCPTRS) {			\
		regs->ARM_r7 = r7;					\
		regs->ARM_r8 = r8;					\
		regs->ARM_r9 = r9;					\
		regs->ARM_r10 = current->mm->start_data;		\
	} else if (!IS_ENABLED(CONFIG_MMU))				\
		regs->ARM_r10 = current->mm->start_data;		\
	if (current->personality & ADDR_LIMIT_32BIT)			\
		regs->ARM_cpsr = USR_MODE;				\
	else								\
		regs->ARM_cpsr = USR26_MODE;				\
	if (elf_hwcap & HWCAP_THUMB && pc & 1)				\
		regs->ARM_cpsr |= PSR_T_BIT;				\
	regs->ARM_cpsr |= PSR_ENDSTATE;					\
	regs->ARM_pc = pc & ~1;		/* pc */			\
	regs->ARM_sp = sp;		/* sp */			\
})

/* 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);

#if __LINUX_ARM_ARCH__ == 6 || defined(CONFIG_ARM_ERRATA_754327)
#define cpu_relax()						\
	do {							\
		smp_mb();					\
		__asm__ __volatile__("nop; nop; nop; nop; nop; nop; nop; nop; nop; nop;");	\
	} while (0)
#else
#define cpu_relax()			barrier()
#endif

#define task_pt_regs(p) \
	((struct pt_regs *)(THREAD_START_SP + task_stack_page(p)) - 1)

#define KSTK_EIP(tsk)	task_pt_regs(tsk)->ARM_pc
#define KSTK_ESP(tsk)	task_pt_regs(tsk)->ARM_sp

#ifdef CONFIG_SMP
#define __ALT_SMP_ASM(smp, up)						\
	"9998:	" smp "\n"						\
	"	.pushsection \".alt.smp.init\", \"a\"\n"		\
	"	.long	9998b\n"					\
	"	" up "\n"						\
	"	.popsection\n"
#else
#define __ALT_SMP_ASM(smp, up)	up
#endif

/*
 * Prefetching support - only ARMv5.
 */
#if __LINUX_ARM_ARCH__ >= 5

#define ARCH_HAS_PREFETCH
static inline void prefetch(const void *ptr)
{
	__asm__ __volatile__(
		"pld\t%a0"
		:: "p" (ptr));
}

#if __LINUX_ARM_ARCH__ >= 7 && defined(CONFIG_SMP)
#define ARCH_HAS_PREFETCHW
static inline void prefetchw(const void *ptr)
{
	__asm__ __volatile__(
		".arch_extension	mp\n"
		__ALT_SMP_ASM(
			"pldw\t%a0",
			"pld\t%a0"
		)
		:: "p" (ptr));
}
#endif
#endif

#endif

#endif /* __ASM_ARM_PROCESSOR_H */