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x86: x86 ptrace getreg/putreg cleanup 

This cleans up the getreg/putreg functions to move the special cases
(segment registers and eflags) out into their own subroutines.

Signed-off-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
Roland McGrath 2008-01-30 13:31:01 +01:00 committed by Ingo Molnar
parent e39c289141
commit 06ee1b687a
1 changed files with 96 additions and 66 deletions
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162
arch/x86/kernel/ptrace.c
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@ -45,92 +45,122 @@
static long *pt_regs_access(struct pt_regs *regs, unsigned long regno)
{
BUILD_BUG_ON(offsetof(struct pt_regs, bx) != 0);
regno >>= 2;
if (regno > FS)
--regno;
return &regs->bx + regno;
}
static int putreg(struct task_struct *child,
unsigned long regno, unsigned long value)
static u16 get_segment_reg(struct task_struct *task, unsigned long offset)
{
struct pt_regs *regs = task_pt_regs(child);
regno >>= 2;
switch (regno) {
case GS:
if (value && (value & 3) != 3)
return -EIO;
child->thread.gs = value;
if (child == current)
/*
* Returning the value truncates it to 16 bits.
*/
unsigned int retval;
if (offset != offsetof(struct user_regs_struct, gs))
retval = *pt_regs_access(task_pt_regs(task), offset);
else {
retval = task->thread.gs;
if (task == current)
savesegment(gs, retval);
}
return retval;
}
static int set_segment_reg(struct task_struct *task,
unsigned long offset, u16 value)
{
/*
* The value argument was already truncated to 16 bits.
*/
if (value && (value & 3) != 3)
return -EIO;
if (offset != offsetof(struct user_regs_struct, gs))
*pt_regs_access(task_pt_regs(task), offset) = value;
else {
task->thread.gs = value;
if (task == current)
/*
* The user-mode %gs is not affected by
* kernel entry, so we must update the CPU.
*/
loadsegment(gs, value);
return 0;
case DS:
case ES:
case FS:
if (value && (value & 3) != 3)
return -EIO;
value &= 0xffff;
break;
case SS:
case CS:
if ((value & 3) != 3)
return -EIO;
value &= 0xffff;
break;
case EFL:
value &= FLAG_MASK;
/*
* If the user value contains TF, mark that
* it was not "us" (the debugger) that set it.
* If not, make sure it stays set if we had.
*/
if (value & X86_EFLAGS_TF)
clear_tsk_thread_flag(child, TIF_FORCED_TF);
else if (test_tsk_thread_flag(child, TIF_FORCED_TF))
value |= X86_EFLAGS_TF;
value |= regs->flags & ~FLAG_MASK;
break;
}
*pt_regs_access(regs, regno) = value;
return 0;
}
static unsigned long getreg(struct task_struct *child, unsigned long regno)
static unsigned long get_flags(struct task_struct *task)
{
struct pt_regs *regs = task_pt_regs(child);
unsigned long retval = ~0UL;
unsigned long retval = task_pt_regs(task)->flags;
/*
* If the debugger set TF, hide it from the readout.
*/
if (test_tsk_thread_flag(task, TIF_FORCED_TF))
retval &= ~X86_EFLAGS_TF;
regno >>= 2;
switch (regno) {
case EFL:
/*
* If the debugger set TF, hide it from the readout.
*/
retval = regs->flags;
if (test_tsk_thread_flag(child, TIF_FORCED_TF))
retval &= ~X86_EFLAGS_TF;
break;
case GS:
retval = child->thread.gs;
if (child == current)
savesegment(gs, retval);
break;
case DS:
case ES:
case FS:
case SS:
case CS:
retval = 0xffff;
/* fall through */
default:
retval &= *pt_regs_access(regs, regno);
}
return retval;
}
static int set_flags(struct task_struct *task, unsigned long value)
{
struct pt_regs *regs = task_pt_regs(task);
/*
* If the user value contains TF, mark that
* it was not "us" (the debugger) that set it.
* If not, make sure it stays set if we had.
*/
if (value & X86_EFLAGS_TF)
clear_tsk_thread_flag(task, TIF_FORCED_TF);
else if (test_tsk_thread_flag(task, TIF_FORCED_TF))
value |= X86_EFLAGS_TF;
regs->flags = (regs->flags & ~FLAG_MASK) | (value & FLAG_MASK);
return 0;
}
static int putreg(struct task_struct *child,
unsigned long offset, unsigned long value)
{
switch (offset) {
case offsetof(struct user_regs_struct, cs):
case offsetof(struct user_regs_struct, ds):
case offsetof(struct user_regs_struct, es):
case offsetof(struct user_regs_struct, fs):
case offsetof(struct user_regs_struct, gs):
case offsetof(struct user_regs_struct, ss):
return set_segment_reg(child, offset, value);
case offsetof(struct user_regs_struct, flags):
return set_flags(child, value);
}
*pt_regs_access(task_pt_regs(child), offset) = value;
return 0;
}
static unsigned long getreg(struct task_struct *task, unsigned long offset)
{
switch (offset) {
case offsetof(struct user_regs_struct, cs):
case offsetof(struct user_regs_struct, ds):
case offsetof(struct user_regs_struct, es):
case offsetof(struct user_regs_struct, fs):
case offsetof(struct user_regs_struct, gs):
case offsetof(struct user_regs_struct, ss):
return get_segment_reg(task, offset);
case offsetof(struct user_regs_struct, flags):
return get_flags(task);
}
return *pt_regs_access(task_pt_regs(task), offset);
}
/*
* This function is trivial and will be inlined by the compiler.
* Having it separates the implementation details of debug