/usr/share/systemtap/runtime
Edit: /usr/share/systemtap/runtime/regs.c (4280B)
/* -*- linux-c -*-
* Functions to access the members of pt_regs struct
* Copyright (C) 2005, 2007 Red Hat Inc.
* Copyright (C) 2005 Intel Corporation.
* Copyright (C) 2007 Quentin Barnes.
*
* This file is part of systemtap, and is free software. You can
* redistribute it and/or modify it under the terms of the GNU General
* Public License (GPL); either version 2, or (at your option) any
* later version.
*/
#ifndef _REGS_C_
#define _REGS_C_
#include "regs.h"
#if defined(__KERNEL__)
#include "linux/regs.c"
#elif defined(__DYNINST__)
#include "dyninst/regs.c"
#endif
/* Function arguments */
#define _STP_REGPARM 0x8000
#define _STP_REGPARM_MASK ((_STP_REGPARM) - 1)
/*
* x86_64 and i386 are especially ugly because:
* 1) the pt_reg member names changed as part of the x86 merge. We use
* either the pre-merge name or the post-merge name, as needed.
* 2) -m32 apps on x86_64 look like i386 apps, so we need to support
* those semantics on both i386 and x86_64.
*/
#ifdef __i386__
static long _stp_get_sp(struct pt_regs *regs)
{
if (!user_mode(regs))
return (long) &EREG(sp, regs);
return EREG(sp, regs);
}
#endif /* __i386__ */
#ifdef __x86_64__
static long _stp_get_sp(struct pt_regs *regs)
{
return RREG(sp, regs);
}
#endif /* __x86_64__ */
#if defined(__x86_64__) || defined(__ia64__) || defined(__i386__)
/* Ensure that the upper 32 bits of val are a sign-extension of the lower 32. */
static int64_t __stp_sign_extend32(int64_t val)
{
int32_t *val_ptr32 = (int32_t*) &val;
return *val_ptr32;
}
/* Ensure that the upper 48 bits of val are a sign-extension of the lower 16. */
static int64_t __stp_sign_extend16(int64_t val)
{
int16_t *val_ptr16 = (int16_t*) &val;
return *val_ptr16;
}
/* Ensure that the upper 56 bits of val are a sign-extension of the lower 8. */
static int64_t __stp_sign_extend8(int64_t val)
{
int8_t *val_ptr8 = (int8_t*) &val;
return *val_ptr8;
}
#endif /* __x86_64__ || __ia64__ || __i386__ */
#if defined(__i386__) || defined(__x86_64__)
/*
* Use this for i386 kernel and apps, and for 32-bit apps running on x86_64.
* Does arch-specific work for fetching function arg #argnum (1 = first arg).
* nr_regargs is the number of arguments that reside in registers (e.g.,
* 3 for fastcall functions).
* Returns:
* 0 if the arg resides in a register. *val contains its value.
* 1 if the arg resides on the kernel stack. *val contains its address.
* 2 if the arg resides on the user stack. *val contains its address.
* -1 if the arg number is invalid.
* We assume that the regs pointer is valid.
*/
#if defined(__i386__)
#define ERREG(nm, regs) EREG(nm, regs)
#else /* x86_64 */
#define ERREG(nm, regs) RREG(nm, regs)
#endif
static int _stp_get_arg32_by_number(int n, int nr_regargs,
struct pt_regs *regs, long *val)
{
if (nr_regargs < 0)
return -1;
if (n > nr_regargs) {
/*
* The typical case: arg n is on the stack.
* stack[0] = return address
*/
int stack_index = n - nr_regargs;
int32_t *stack = (int32_t*) _stp_get_sp(regs);
*val = (long) &stack[stack_index];
return (user_mode(regs) ? 2 : 1);
} else {
switch (n) {
case 1: *val = (int32_t)(ERREG(ax, regs)); break;
case 2: *val = (int32_t)(ERREG(dx, regs)); break;
case 3: *val = (int32_t)(ERREG(cx, regs)); break;
default:
/* gcc rejects regparm values > 3. */
return -1;
}
return 0;
}
}
#endif /* __i386__ || __x86_64__ */
#ifdef __x86_64__
/* See _stp_get_arg32_by_number(). */
static int _stp_get_arg64_by_number(int n, int nr_regargs,
struct pt_regs *regs, unsigned long *val)
{
if (nr_regargs < 0)
return -1;
if (n > nr_regargs) {
/* arg n is on the stack. stack[0] = return address */
int stack_index = n - nr_regargs;
unsigned long *stack = (unsigned long*) _stp_get_sp(regs);
*val = (unsigned long) &stack[stack_index];
return (user_mode(regs) ? 2 : 1);
} else {
switch (n) {
case 1: *val = RREG(di, regs); break;
case 2: *val = RREG(si, regs); break;
case 3: *val = RREG(dx, regs); break;
case 4: *val = RREG(cx, regs); break;
case 5: *val = regs->r8; break;
case 6: *val = regs->r9; break;
default:
/* gcc rejects regparm values > 6. */
return -1;
}
return 0;
}
}
#endif /* __x86_64__ */
/** @} */
#endif /* _REGS_C_ */