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linuxdebug/arch/parisc/kernel/ptrace.c

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null pointer error
2024-07-16 15:50:57 +02:00
// SPDX-License-Identifier: GPL-2.0
/*
* Kernel support for the ptrace() and syscall tracing interfaces.
*
* Copyright (C) 2000 Hewlett-Packard Co, Linuxcare Inc.
* Copyright (C) 2000 Matthew Wilcox <matthew@wil.cx>
* Copyright (C) 2000 David Huggins-Daines <dhd@debian.org>
* Copyright (C) 2008-2016 Helge Deller <deller@gmx.de>
*/
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/smp.h>
#include <linux/elf.h>
#include <linux/errno.h>
#include <linux/ptrace.h>
#include <linux/user.h>
#include <linux/personality.h>
#include <linux/regset.h>
#include <linux/security.h>
#include <linux/seccomp.h>
#include <linux/compat.h>
#include <linux/signal.h>
#include <linux/audit.h>
#include <linux/uaccess.h>
#include <asm/processor.h>
#include <asm/asm-offsets.h>
/* PSW bits we allow the debugger to modify */
#define USER_PSW_BITS (PSW_N | PSW_B | PSW_V | PSW_CB)
#define CREATE_TRACE_POINTS
#include <trace/events/syscalls.h>
/*
* These are our native regset flavors.
*/
enum parisc_regset {
REGSET_GENERAL,
REGSET_FP
};
/*
* Called by kernel/ptrace.c when detaching..
*
* Make sure single step bits etc are not set.
*/
void ptrace_disable(struct task_struct *task)
{
clear_tsk_thread_flag(task, TIF_SINGLESTEP);
clear_tsk_thread_flag(task, TIF_BLOCKSTEP);
/* make sure the trap bits are not set */
pa_psw(task)->r = 0;
pa_psw(task)->t = 0;
pa_psw(task)->h = 0;
pa_psw(task)->l = 0;
}
/*
* The following functions are called by ptrace_resume() when
* enabling or disabling single/block tracing.
*/
void user_disable_single_step(struct task_struct *task)
{
ptrace_disable(task);
}
void user_enable_single_step(struct task_struct *task)
{
clear_tsk_thread_flag(task, TIF_BLOCKSTEP);
set_tsk_thread_flag(task, TIF_SINGLESTEP);
if (pa_psw(task)->n) {
/* Nullified, just crank over the queue. */
task_regs(task)->iaoq[0] = task_regs(task)->iaoq[1];
task_regs(task)->iasq[0] = task_regs(task)->iasq[1];
task_regs(task)->iaoq[1] = task_regs(task)->iaoq[0] + 4;
pa_psw(task)->n = 0;
pa_psw(task)->x = 0;
pa_psw(task)->y = 0;
pa_psw(task)->z = 0;
pa_psw(task)->b = 0;
ptrace_disable(task);
/* Don't wake up the task, but let the
parent know something happened. */
force_sig_fault_to_task(SIGTRAP, TRAP_TRACE,
(void __user *) (task_regs(task)->iaoq[0] & ~3),
task);
/* notify_parent(task, SIGCHLD); */
return;
}
/* Enable recovery counter traps. The recovery counter
* itself will be set to zero on a task switch. If the
* task is suspended on a syscall then the syscall return
* path will overwrite the recovery counter with a suitable
* value such that it traps once back in user space. We
* disable interrupts in the tasks PSW here also, to avoid
* interrupts while the recovery counter is decrementing.
*/
pa_psw(task)->r = 1;
pa_psw(task)->t = 0;
pa_psw(task)->h = 0;
pa_psw(task)->l = 0;
}
void user_enable_block_step(struct task_struct *task)
{
clear_tsk_thread_flag(task, TIF_SINGLESTEP);
set_tsk_thread_flag(task, TIF_BLOCKSTEP);
/* Enable taken branch trap. */
pa_psw(task)->r = 0;
pa_psw(task)->t = 1;
pa_psw(task)->h = 0;
pa_psw(task)->l = 0;
}
long arch_ptrace(struct task_struct *child, long request,
unsigned long addr, unsigned long data)
{
unsigned long __user *datap = (unsigned long __user *)data;
unsigned long tmp;
long ret = -EIO;
unsigned long user_regs_struct_size = sizeof(struct user_regs_struct);
#ifdef CONFIG_64BIT
if (is_compat_task())
user_regs_struct_size /= 2;
#endif
switch (request) {
/* Read the word at location addr in the USER area. For ptraced
processes, the kernel saves all regs on a syscall. */
case PTRACE_PEEKUSR:
if ((addr & (sizeof(unsigned long)-1)) ||
addr >= sizeof(struct pt_regs))
break;
tmp = *(unsigned long *) ((char *) task_regs(child) + addr);
ret = put_user(tmp, datap);
break;
/* Write the word at location addr in the USER area. This will need
to change when the kernel no longer saves all regs on a syscall.
FIXME. There is a problem at the moment in that r3-r18 are only
saved if the process is ptraced on syscall entry, and even then
those values are overwritten by actual register values on syscall
exit. */
case PTRACE_POKEUSR:
/* Some register values written here may be ignored in
* entry.S:syscall_restore_rfi; e.g. iaoq is written with
* r31/r31+4, and not with the values in pt_regs.
*/
if (addr == PT_PSW) {
/* Allow writing to Nullify, Divide-step-correction,
* and carry/borrow bits.
* BEWARE, if you set N, and then single step, it won't
* stop on the nullified instruction.
*/
data &= USER_PSW_BITS;
task_regs(child)->gr[0] &= ~USER_PSW_BITS;
task_regs(child)->gr[0] |= data;
ret = 0;
break;
}
if ((addr & (sizeof(unsigned long)-1)) ||
addr >= sizeof(struct pt_regs))
break;
if (addr == PT_IAOQ0 || addr == PT_IAOQ1) {
data |= PRIV_USER; /* ensure userspace privilege */
}
if ((addr >= PT_GR1 && addr <= PT_GR31) ||
addr == PT_IAOQ0 || addr == PT_IAOQ1 ||
(addr >= PT_FR0 && addr <= PT_FR31 + 4) ||
addr == PT_SAR) {
*(unsigned long *) ((char *) task_regs(child) + addr) = data;
ret = 0;
}
break;
case PTRACE_GETREGS: /* Get all gp regs from the child. */
return copy_regset_to_user(child,
task_user_regset_view(current),
REGSET_GENERAL,
0, user_regs_struct_size,
datap);
case PTRACE_SETREGS: /* Set all gp regs in the child. */
return copy_regset_from_user(child,
task_user_regset_view(current),
REGSET_GENERAL,
0, user_regs_struct_size,
datap);
case PTRACE_GETFPREGS: /* Get the child FPU state. */
return copy_regset_to_user(child,
task_user_regset_view(current),
REGSET_FP,
0, sizeof(struct user_fp_struct),
datap);
case PTRACE_SETFPREGS: /* Set the child FPU state. */
return copy_regset_from_user(child,
task_user_regset_view(current),
REGSET_FP,
0, sizeof(struct user_fp_struct),
datap);
default:
ret = ptrace_request(child, request, addr, data);
break;
}
return ret;
}
#ifdef CONFIG_COMPAT
/* This function is needed to translate 32 bit pt_regs offsets in to
* 64 bit pt_regs offsets. For example, a 32 bit gdb under a 64 bit kernel
* will request offset 12 if it wants gr3, but the lower 32 bits of
* the 64 bit kernels view of gr3 will be at offset 28 (3*8 + 4).
* This code relies on a 32 bit pt_regs being comprised of 32 bit values
* except for the fp registers which (a) are 64 bits, and (b) follow
* the gr registers at the start of pt_regs. The 32 bit pt_regs should
* be half the size of the 64 bit pt_regs, plus 32*4 to allow for fr[]
* being 64 bit in both cases.
*/
static compat_ulong_t translate_usr_offset(compat_ulong_t offset)
{
compat_ulong_t pos;
if (offset < 32*4) /* gr[0..31] */
pos = offset * 2 + 4;
else if (offset < 32*4+32*8) /* fr[0] ... fr[31] */
pos = (offset - 32*4) + PT_FR0;
else if (offset < sizeof(struct pt_regs)/2 + 32*4) /* sr[0] ... ipsw */
pos = (offset - 32*4 - 32*8) * 2 + PT_SR0 + 4;
else
pos = sizeof(struct pt_regs);
return pos;
}
long compat_arch_ptrace(struct task_struct *child, compat_long_t request,
compat_ulong_t addr, compat_ulong_t data)
{
compat_uint_t tmp;
long ret = -EIO;
switch (request) {
case PTRACE_PEEKUSR:
if (addr & (sizeof(compat_uint_t)-1))
break;
addr = translate_usr_offset(addr);
if (addr >= sizeof(struct pt_regs))
break;
tmp = *(compat_uint_t *) ((char *) task_regs(child) + addr);
ret = put_user(tmp, (compat_uint_t *) (unsigned long) data);
break;
/* Write the word at location addr in the USER area. This will need
to change when the kernel no longer saves all regs on a syscall.
FIXME. There is a problem at the moment in that r3-r18 are only
saved if the process is ptraced on syscall entry, and even then
those values are overwritten by actual register values on syscall
exit. */
case PTRACE_POKEUSR:
/* Some register values written here may be ignored in
* entry.S:syscall_restore_rfi; e.g. iaoq is written with
* r31/r31+4, and not with the values in pt_regs.
*/
if (addr == PT_PSW) {
/* Since PT_PSW==0, it is valid for 32 bit processes
* under 64 bit kernels as well.
*/
ret = arch_ptrace(child, request, addr, data);
} else {
if (addr & (sizeof(compat_uint_t)-1))
break;
addr = translate_usr_offset(addr);
if (addr >= sizeof(struct pt_regs))
break;
if (addr == PT_IAOQ0+4 || addr == PT_IAOQ1+4) {
data |= PRIV_USER; /* ensure userspace privilege */
}
if (addr >= PT_FR0 && addr <= PT_FR31 + 4) {
/* Special case, fp regs are 64 bits anyway */
*(__u32 *) ((char *) task_regs(child) + addr) = data;
ret = 0;
}
else if ((addr >= PT_GR1+4 && addr <= PT_GR31+4) ||
addr == PT_IAOQ0+4 || addr == PT_IAOQ1+4 ||
addr == PT_SAR+4) {
/* Zero the top 32 bits */
*(__u32 *) ((char *) task_regs(child) + addr - 4) = 0;
*(__u32 *) ((char *) task_regs(child) + addr) = data;
ret = 0;
}
}
break;
case PTRACE_GETREGS:
case PTRACE_SETREGS:
case PTRACE_GETFPREGS:
case PTRACE_SETFPREGS:
return arch_ptrace(child, request, addr, data);
default:
ret = compat_ptrace_request(child, request, addr, data);
break;
}
return ret;
}
#endif
long do_syscall_trace_enter(struct pt_regs *regs)
{
if (test_thread_flag(TIF_SYSCALL_TRACE)) {
int rc = ptrace_report_syscall_entry(regs);
/*
* As tracesys_next does not set %r28 to -ENOSYS
* when %r20 is set to -1, initialize it here.
*/
regs->gr[28] = -ENOSYS;
if (rc) {
/*
* A nonzero return code from
* ptrace_report_syscall_entry() tells us
* to prevent the syscall execution. Skip
* the syscall call and the syscall restart handling.
*
* Note that the tracer may also just change
* regs->gr[20] to an invalid syscall number,
* that is handled by tracesys_next.
*/
regs->gr[20] = -1UL;
return -1;
}
}
/* Do the secure computing check after ptrace. */
if (secure_computing() == -1)
return -1;
#ifdef CONFIG_HAVE_SYSCALL_TRACEPOINTS
if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT)))
trace_sys_enter(regs, regs->gr[20]);
#endif
#ifdef CONFIG_64BIT
if (!is_compat_task())
audit_syscall_entry(regs->gr[20], regs->gr[26], regs->gr[25],
regs->gr[24], regs->gr[23]);
else
#endif
audit_syscall_entry(regs->gr[20] & 0xffffffff,
regs->gr[26] & 0xffffffff,
regs->gr[25] & 0xffffffff,
regs->gr[24] & 0xffffffff,
regs->gr[23] & 0xffffffff);
/*
* Sign extend the syscall number to 64bit since it may have been
* modified by a compat ptrace call
*/
return (int) ((u32) regs->gr[20]);
}
void do_syscall_trace_exit(struct pt_regs *regs)
{
int stepping = test_thread_flag(TIF_SINGLESTEP) ||
test_thread_flag(TIF_BLOCKSTEP);
audit_syscall_exit(regs);
#ifdef CONFIG_HAVE_SYSCALL_TRACEPOINTS
if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT)))
trace_sys_exit(regs, regs->gr[20]);
#endif
if (stepping || test_thread_flag(TIF_SYSCALL_TRACE))
ptrace_report_syscall_exit(regs, stepping);
}
/*
* regset functions.
*/
static int fpr_get(struct task_struct *target,
const struct user_regset *regset,
struct membuf to)
{
struct pt_regs *regs = task_regs(target);
return membuf_write(&to, regs->fr, ELF_NFPREG * sizeof(__u64));
}
static int fpr_set(struct task_struct *target,
const struct user_regset *regset,
unsigned int pos, unsigned int count,
const void *kbuf, const void __user *ubuf)
{
struct pt_regs *regs = task_regs(target);
const __u64 *k = kbuf;
const __u64 __user *u = ubuf;
__u64 reg;
pos /= sizeof(reg);
count /= sizeof(reg);
if (kbuf)
for (; count > 0 && pos < ELF_NFPREG; --count)
regs->fr[pos++] = *k++;
else
for (; count > 0 && pos < ELF_NFPREG; --count) {
if (__get_user(reg, u++))
return -EFAULT;
regs->fr[pos++] = reg;
}
kbuf = k;
ubuf = u;
pos *= sizeof(reg);
count *= sizeof(reg);
return user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
ELF_NFPREG * sizeof(reg), -1);
}
#define RI(reg) (offsetof(struct user_regs_struct,reg) / sizeof(long))
static unsigned long get_reg(struct pt_regs *regs, int num)
{
switch (num) {
case RI(gr[0]) ... RI(gr[31]): return regs->gr[num - RI(gr[0])];
case RI(sr[0]) ... RI(sr[7]): return regs->sr[num - RI(sr[0])];
case RI(iasq[0]): return regs->iasq[0];
case RI(iasq[1]): return regs->iasq[1];
case RI(iaoq[0]): return regs->iaoq[0];
case RI(iaoq[1]): return regs->iaoq[1];
case RI(sar): return regs->sar;
case RI(iir): return regs->iir;
case RI(isr): return regs->isr;
case RI(ior): return regs->ior;
case RI(ipsw): return regs->ipsw;
case RI(cr27): return regs->cr27;
case RI(cr0): return mfctl(0);
case RI(cr24): return mfctl(24);
case RI(cr25): return mfctl(25);
case RI(cr26): return mfctl(26);
case RI(cr28): return mfctl(28);
case RI(cr29): return mfctl(29);
case RI(cr30): return mfctl(30);
case RI(cr31): return mfctl(31);
case RI(cr8): return mfctl(8);
case RI(cr9): return mfctl(9);
case RI(cr12): return mfctl(12);
case RI(cr13): return mfctl(13);
case RI(cr10): return mfctl(10);
case RI(cr15): return mfctl(15);
default: return 0;
}
}
static void set_reg(struct pt_regs *regs, int num, unsigned long val)
{
switch (num) {
case RI(gr[0]): /*
* PSW is in gr[0].
* Allow writing to Nullify, Divide-step-correction,
* and carry/borrow bits.
* BEWARE, if you set N, and then single step, it won't
* stop on the nullified instruction.
*/
val &= USER_PSW_BITS;
regs->gr[0] &= ~USER_PSW_BITS;
regs->gr[0] |= val;
return;
case RI(gr[1]) ... RI(gr[31]):
regs->gr[num - RI(gr[0])] = val;
return;
case RI(iaoq[0]):
case RI(iaoq[1]):
/* set 2 lowest bits to ensure userspace privilege: */
regs->iaoq[num - RI(iaoq[0])] = val | PRIV_USER;
return;
case RI(sar): regs->sar = val;
return;
default: return;
#if 0
/* do not allow to change any of the following registers (yet) */
case RI(sr[0]) ... RI(sr[7]): return regs->sr[num - RI(sr[0])];
case RI(iasq[0]): return regs->iasq[0];
case RI(iasq[1]): return regs->iasq[1];
case RI(iir): return regs->iir;
case RI(isr): return regs->isr;
case RI(ior): return regs->ior;
case RI(ipsw): return regs->ipsw;
case RI(cr27): return regs->cr27;
case cr0, cr24, cr25, cr26, cr27, cr28, cr29, cr30, cr31;
case cr8, cr9, cr12, cr13, cr10, cr15;
#endif
}
}
static int gpr_get(struct task_struct *target,
const struct user_regset *regset,
struct membuf to)
{
struct pt_regs *regs = task_regs(target);
unsigned int pos;
for (pos = 0; pos < ELF_NGREG; pos++)
membuf_store(&to, get_reg(regs, pos));
return 0;
}
static int gpr_set(struct task_struct *target,
const struct user_regset *regset,
unsigned int pos, unsigned int count,
const void *kbuf, const void __user *ubuf)
{
struct pt_regs *regs = task_regs(target);
const unsigned long *k = kbuf;
const unsigned long __user *u = ubuf;
unsigned long reg;
pos /= sizeof(reg);
count /= sizeof(reg);
if (kbuf)
for (; count > 0 && pos < ELF_NGREG; --count)
set_reg(regs, pos++, *k++);
else
for (; count > 0 && pos < ELF_NGREG; --count) {
if (__get_user(reg, u++))
return -EFAULT;
set_reg(regs, pos++, reg);
}
kbuf = k;
ubuf = u;
pos *= sizeof(reg);
count *= sizeof(reg);
return user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
ELF_NGREG * sizeof(reg), -1);
}
static const struct user_regset native_regsets[] = {
[REGSET_GENERAL] = {
.core_note_type = NT_PRSTATUS, .n = ELF_NGREG,
.size = sizeof(long), .align = sizeof(long),
.regset_get = gpr_get, .set = gpr_set
},
[REGSET_FP] = {
.core_note_type = NT_PRFPREG, .n = ELF_NFPREG,
.size = sizeof(__u64), .align = sizeof(__u64),
.regset_get = fpr_get, .set = fpr_set
}
};
static const struct user_regset_view user_parisc_native_view = {
.name = "parisc", .e_machine = ELF_ARCH, .ei_osabi = ELFOSABI_LINUX,
.regsets = native_regsets, .n = ARRAY_SIZE(native_regsets)
};
#ifdef CONFIG_64BIT
static int gpr32_get(struct task_struct *target,
const struct user_regset *regset,
struct membuf to)
{
struct pt_regs *regs = task_regs(target);
unsigned int pos;
for (pos = 0; pos < ELF_NGREG; pos++)
membuf_store(&to, (compat_ulong_t)get_reg(regs, pos));
return 0;
}
static int gpr32_set(struct task_struct *target,
const struct user_regset *regset,
unsigned int pos, unsigned int count,
const void *kbuf, const void __user *ubuf)
{
struct pt_regs *regs = task_regs(target);
const compat_ulong_t *k = kbuf;
const compat_ulong_t __user *u = ubuf;
compat_ulong_t reg;
pos /= sizeof(reg);
count /= sizeof(reg);
if (kbuf)
for (; count > 0 && pos < ELF_NGREG; --count)
set_reg(regs, pos++, *k++);
else
for (; count > 0 && pos < ELF_NGREG; --count) {
if (__get_user(reg, u++))
return -EFAULT;
set_reg(regs, pos++, reg);
}
kbuf = k;
ubuf = u;
pos *= sizeof(reg);
count *= sizeof(reg);
return user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
ELF_NGREG * sizeof(reg), -1);
}
/*
* These are the regset flavors matching the 32bit native set.
*/
static const struct user_regset compat_regsets[] = {
[REGSET_GENERAL] = {
.core_note_type = NT_PRSTATUS, .n = ELF_NGREG,
.size = sizeof(compat_long_t), .align = sizeof(compat_long_t),
.regset_get = gpr32_get, .set = gpr32_set
},
[REGSET_FP] = {
.core_note_type = NT_PRFPREG, .n = ELF_NFPREG,
.size = sizeof(__u64), .align = sizeof(__u64),
.regset_get = fpr_get, .set = fpr_set
}
};
static const struct user_regset_view user_parisc_compat_view = {
.name = "parisc", .e_machine = EM_PARISC, .ei_osabi = ELFOSABI_LINUX,
.regsets = compat_regsets, .n = ARRAY_SIZE(compat_regsets)
};
#endif /* CONFIG_64BIT */
const struct user_regset_view *task_user_regset_view(struct task_struct *task)
{
BUILD_BUG_ON(sizeof(struct user_regs_struct)/sizeof(long) != ELF_NGREG);
BUILD_BUG_ON(sizeof(struct user_fp_struct)/sizeof(__u64) != ELF_NFPREG);
#ifdef CONFIG_64BIT
if (is_compat_task())
return &user_parisc_compat_view;
#endif
return &user_parisc_native_view;
}
/* HAVE_REGS_AND_STACK_ACCESS_API feature */
struct pt_regs_offset {
const char *name;
int offset;
};
#define REG_OFFSET_NAME(r) {.name = #r, .offset = offsetof(struct pt_regs, r)}
#define REG_OFFSET_INDEX(r,i) {.name = #r#i, .offset = offsetof(struct pt_regs, r[i])}
#define REG_OFFSET_END {.name = NULL, .offset = 0}
static const struct pt_regs_offset regoffset_table[] = {
REG_OFFSET_INDEX(gr,0),
REG_OFFSET_INDEX(gr,1),
REG_OFFSET_INDEX(gr,2),
REG_OFFSET_INDEX(gr,3),
REG_OFFSET_INDEX(gr,4),
REG_OFFSET_INDEX(gr,5),
REG_OFFSET_INDEX(gr,6),
REG_OFFSET_INDEX(gr,7),
REG_OFFSET_INDEX(gr,8),
REG_OFFSET_INDEX(gr,9),
REG_OFFSET_INDEX(gr,10),
REG_OFFSET_INDEX(gr,11),
REG_OFFSET_INDEX(gr,12),
REG_OFFSET_INDEX(gr,13),
REG_OFFSET_INDEX(gr,14),
REG_OFFSET_INDEX(gr,15),
REG_OFFSET_INDEX(gr,16),
REG_OFFSET_INDEX(gr,17),
REG_OFFSET_INDEX(gr,18),
REG_OFFSET_INDEX(gr,19),
REG_OFFSET_INDEX(gr,20),
REG_OFFSET_INDEX(gr,21),
REG_OFFSET_INDEX(gr,22),
REG_OFFSET_INDEX(gr,23),
REG_OFFSET_INDEX(gr,24),
REG_OFFSET_INDEX(gr,25),
REG_OFFSET_INDEX(gr,26),
REG_OFFSET_INDEX(gr,27),
REG_OFFSET_INDEX(gr,28),
REG_OFFSET_INDEX(gr,29),
REG_OFFSET_INDEX(gr,30),
REG_OFFSET_INDEX(gr,31),
REG_OFFSET_INDEX(sr,0),
REG_OFFSET_INDEX(sr,1),
REG_OFFSET_INDEX(sr,2),
REG_OFFSET_INDEX(sr,3),
REG_OFFSET_INDEX(sr,4),
REG_OFFSET_INDEX(sr,5),
REG_OFFSET_INDEX(sr,6),
REG_OFFSET_INDEX(sr,7),
REG_OFFSET_INDEX(iasq,0),
REG_OFFSET_INDEX(iasq,1),
REG_OFFSET_INDEX(iaoq,0),
REG_OFFSET_INDEX(iaoq,1),
REG_OFFSET_NAME(cr27),
REG_OFFSET_NAME(ksp),
REG_OFFSET_NAME(kpc),
REG_OFFSET_NAME(sar),
REG_OFFSET_NAME(iir),
REG_OFFSET_NAME(isr),
REG_OFFSET_NAME(ior),
REG_OFFSET_NAME(ipsw),
REG_OFFSET_END,
};
/**
* regs_query_register_offset() - query register offset from its name
* @name: the name of a register
*
* regs_query_register_offset() returns the offset of a register in struct
* pt_regs from its name. If the name is invalid, this returns -EINVAL;
*/
int regs_query_register_offset(const char *name)
{
const struct pt_regs_offset *roff;
for (roff = regoffset_table; roff->name != NULL; roff++)
if (!strcmp(roff->name, name))
return roff->offset;
return -EINVAL;
}
/**
* regs_query_register_name() - query register name from its offset
* @offset: the offset of a register in struct pt_regs.
*
* regs_query_register_name() returns the name of a register from its
* offset in struct pt_regs. If the @offset is invalid, this returns NULL;
*/
const char *regs_query_register_name(unsigned int offset)
{
const struct pt_regs_offset *roff;
for (roff = regoffset_table; roff->name != NULL; roff++)
if (roff->offset == offset)
return roff->name;
return NULL;
}
/**
* 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.
*/
int 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.
*/
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 0;
return *addr;
}