linux_kernel/arch/powerpc/include/asm/ptrace.h

/*
 * Copyright (C) 2001 PPC64 Team, IBM Corp
 *
 * This struct defines the way the registers are stored on the
 * kernel stack during a system call or other kernel entry.
 *
 * this should only contain volatile regs
 * since we can keep non-volatile in the thread_struct
 * should set this up when only volatiles are saved
 * by intr code.
 *
 * Since this is going on the stack, *CARE MUST BE TAKEN* to insure
 * that the overall structure is a multiple of 16 bytes in length.
 *
 * Note that the offsets of the fields in this struct correspond with
 * the PT_* values below.  This simplifies arch/powerpc/kernel/ptrace.c.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version
 * 2 of the License, or (at your option) any later version.
 */
#ifndef _ASM_POWERPC_PTRACE_H
#define _ASM_POWERPC_PTRACE_H

#include <uapi/asm/ptrace.h>


#ifdef __powerpc64__

/*
 * Size of redzone that userspace is allowed to use below the stack
 * pointer.  This is 288 in the 64-bit big-endian ELF ABI, and 512 in
 * the new ELFv2 little-endian ABI, so we allow the larger amount.
 *
 * For kernel code we allow a 288-byte redzone, in order to conserve
 * kernel stack space; gcc currently only uses 288 bytes, and will
 * hopefully allow explicit control of the redzone size in future.
 */
#define USER_REDZONE_SIZE	512
#define KERNEL_REDZONE_SIZE	288

#define STACK_FRAME_OVERHEAD	112	/* size of minimum stack frame */
#define STACK_FRAME_LR_SAVE	2	/* Location of LR in stack frame */
#define STACK_FRAME_REGS_MARKER	ASM_CONST(0x7265677368657265)
#define STACK_INT_FRAME_SIZE	(sizeof(struct pt_regs) + \
				 STACK_FRAME_OVERHEAD + KERNEL_REDZONE_SIZE)
#define STACK_FRAME_MARKER	12

/* Size of dummy stack frame allocated when calling signal handler. */
#define __SIGNAL_FRAMESIZE	128
#define __SIGNAL_FRAMESIZE32	64

#else /* __powerpc64__ */

#define USER_REDZONE_SIZE	0
#define KERNEL_REDZONE_SIZE	0
#define STACK_FRAME_OVERHEAD	16	/* size of minimum stack frame */
#define STACK_FRAME_LR_SAVE	1	/* Location of LR in stack frame */
#define STACK_FRAME_REGS_MARKER	ASM_CONST(0x72656773)
#define STACK_INT_FRAME_SIZE	(sizeof(struct pt_regs) + STACK_FRAME_OVERHEAD)
#define STACK_FRAME_MARKER	2

/* Size of stack frame allocated when calling signal handler. */
#define __SIGNAL_FRAMESIZE	64

#endif /* __powerpc64__ */

#ifndef __ASSEMBLY__

#define GET_IP(regs)		((regs)->nip)
#define GET_USP(regs)		((regs)->gpr[1])
#define GET_FP(regs)		(0)
#define SET_FP(regs, val)

#ifdef CONFIG_SMP
extern unsigned long profile_pc(struct pt_regs *regs);
#define profile_pc profile_pc
#endif

#include <asm-generic/ptrace.h>

#define kernel_stack_pointer(regs) ((regs)->gpr[1])
static inline int is_syscall_success(struct pt_regs *regs)
{
	return !(regs->ccr & 0x10000000);
}

static inline long regs_return_value(struct pt_regs *regs)
{
	if (is_syscall_success(regs))
		return regs->gpr[3];
	else
		return -regs->gpr[3];
}

#ifdef __powerpc64__
#define user_mode(regs) ((((regs)->msr) >> MSR_PR_LG) & 0x1)
#else
#define user_mode(regs) (((regs)->msr & MSR_PR) != 0)
#endif

#define force_successful_syscall_return()   \
	do { \
		set_thread_flag(TIF_NOERROR); \
	} while(0)

struct task_struct;
extern int ptrace_get_reg(struct task_struct *task, int regno,
			  unsigned long *data);
extern int ptrace_put_reg(struct task_struct *task, int regno,
			  unsigned long data);

#define current_pt_regs() \
	((struct pt_regs *)((unsigned long)current_thread_info() + THREAD_SIZE) - 1)
/*
 * We use the least-significant bit of the trap field to indicate
 * whether we have saved the full set of registers, or only a
 * partial set.  A 1 there means the partial set.
 * On 4xx we use the next bit to indicate whether the exception
 * is a critical exception (1 means it is).
 */
#define FULL_REGS(regs)		(((regs)->trap & 1) == 0)
#ifndef __powerpc64__
#define IS_CRITICAL_EXC(regs)	(((regs)->trap & 2) != 0)
#define IS_MCHECK_EXC(regs)	(((regs)->trap & 4) != 0)
#define IS_DEBUG_EXC(regs)	(((regs)->trap & 8) != 0)
#endif /* ! __powerpc64__ */
#define TRAP(regs)		((regs)->trap & ~0xF)
#ifdef __powerpc64__
#define NV_REG_POISON		0xdeadbeefdeadbeefUL
#define CHECK_FULL_REGS(regs)	BUG_ON(regs->trap & 1)
#else
#define NV_REG_POISON		0xdeadbeef
#define CHECK_FULL_REGS(regs)						      \
do {									      \
	if ((regs)->trap & 1)						      \
		printk(KERN_CRIT "%s: partial register set\n", __func__); \
} while (0)
#endif /* __powerpc64__ */

#define arch_has_single_step()	(1)
#define arch_has_block_step()	(!cpu_has_feature(CPU_FTR_601))
#define ARCH_HAS_USER_SINGLE_STEP_INFO

/*
 * kprobe-based event tracer support
 */

#include <linux/stddef.h>
#include <linux/thread_info.h>
extern int regs_query_register_offset(const char *name);
extern const char *regs_query_register_name(unsigned int offset);
#define MAX_REG_OFFSET (offsetof(struct pt_regs, dsisr))

/**
 * regs_get_register() - get register value from its offset
 * @regs:	   pt_regs from which register value is gotten
 * @offset:    offset number of the register.
 *
 * regs_get_register returns the value of a register whose offset from @regs.
 * The @offset is the offset of the register in struct pt_regs.
 * If @offset is bigger than MAX_REG_OFFSET, this returns 0.
 */
static inline unsigned long regs_get_register(struct pt_regs *regs,
						unsigned int offset)
{
	if (unlikely(offset > MAX_REG_OFFSET))
		return 0;
	return *(unsigned long *)((unsigned long)regs + offset);
}

/**
 * regs_within_kernel_stack() - check the address in the stack
 * @regs:      pt_regs which contains kernel stack pointer.
 * @addr:      address which is checked.
 *
 * regs_within_kernel_stack() checks @addr is within the kernel stack page(s).
 * If @addr is within the kernel stack, it returns true. If not, returns false.
 */

static inline bool regs_within_kernel_stack(struct pt_regs *regs,
						unsigned long addr)
{
	return ((addr & ~(THREAD_SIZE - 1))  ==
		(kernel_stack_pointer(regs) & ~(THREAD_SIZE - 1)));
}

/**
 * regs_get_kernel_stack_nth() - get Nth entry of the stack
 * @regs:	pt_regs which contains kernel stack pointer.
 * @n:		stack entry number.
 *
 * regs_get_kernel_stack_nth() returns @n th entry of the kernel stack which
 * is specified by @regs. If the @n th entry is NOT in the kernel stack,
 * this returns 0.
 */
static inline unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs,
						      unsigned int n)
{
	unsigned long *addr = (unsigned long *)kernel_stack_pointer(regs);
	addr += n;
	if (regs_within_kernel_stack(regs, (unsigned long)addr))
		return *addr;
	else
		return 0;
}

#endif /* __ASSEMBLY__ */

#ifndef __powerpc64__
#else /* __powerpc64__ */
#define PT_FPSCR32 (PT_FPR0 + 2*32 + 1)	/* each FP reg occupies 2 32-bit userspace slots */
#define PT_VR0_32 164	/* each Vector reg occupies 4 slots in 32-bit */
#define PT_VSCR_32 (PT_VR0 + 32*4 + 3)
#define PT_VRSAVE_32 (PT_VR0 + 33*4)
#define PT_VSR0_32 300 	/* each VSR reg occupies 4 slots in 32-bit */
#endif /* __powerpc64__ */
#endif /* _ASM_POWERPC_PTRACE_H */