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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>
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e39c289141
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06ee1b687a
@ -45,92 +45,122 @@
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static long *pt_regs_access(struct pt_regs *regs, unsigned long regno)
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{
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BUILD_BUG_ON(offsetof(struct pt_regs, bx) != 0);
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regno >>= 2;
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if (regno > FS)
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--regno;
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return ®s->bx + regno;
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}
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static int putreg(struct task_struct *child,
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unsigned long regno, unsigned long value)
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static u16 get_segment_reg(struct task_struct *task, unsigned long offset)
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{
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struct pt_regs *regs = task_pt_regs(child);
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regno >>= 2;
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switch (regno) {
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case GS:
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if (value && (value & 3) != 3)
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return -EIO;
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child->thread.gs = value;
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if (child == current)
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/*
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* Returning the value truncates it to 16 bits.
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*/
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unsigned int retval;
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if (offset != offsetof(struct user_regs_struct, gs))
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retval = *pt_regs_access(task_pt_regs(task), offset);
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else {
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retval = task->thread.gs;
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if (task == current)
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savesegment(gs, retval);
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}
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return retval;
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}
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static int set_segment_reg(struct task_struct *task,
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unsigned long offset, u16 value)
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{
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/*
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* The value argument was already truncated to 16 bits.
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*/
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if (value && (value & 3) != 3)
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return -EIO;
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if (offset != offsetof(struct user_regs_struct, gs))
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*pt_regs_access(task_pt_regs(task), offset) = value;
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else {
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task->thread.gs = value;
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if (task == current)
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/*
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* The user-mode %gs is not affected by
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* kernel entry, so we must update the CPU.
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*/
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loadsegment(gs, value);
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return 0;
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case DS:
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case ES:
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case FS:
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if (value && (value & 3) != 3)
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return -EIO;
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value &= 0xffff;
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break;
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case SS:
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case CS:
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if ((value & 3) != 3)
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return -EIO;
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value &= 0xffff;
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break;
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case EFL:
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value &= FLAG_MASK;
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/*
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* If the user value contains TF, mark that
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* it was not "us" (the debugger) that set it.
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* If not, make sure it stays set if we had.
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*/
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if (value & X86_EFLAGS_TF)
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clear_tsk_thread_flag(child, TIF_FORCED_TF);
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else if (test_tsk_thread_flag(child, TIF_FORCED_TF))
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value |= X86_EFLAGS_TF;
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value |= regs->flags & ~FLAG_MASK;
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break;
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}
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*pt_regs_access(regs, regno) = value;
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return 0;
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}
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static unsigned long getreg(struct task_struct *child, unsigned long regno)
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static unsigned long get_flags(struct task_struct *task)
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{
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struct pt_regs *regs = task_pt_regs(child);
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unsigned long retval = ~0UL;
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unsigned long retval = task_pt_regs(task)->flags;
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/*
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* If the debugger set TF, hide it from the readout.
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*/
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if (test_tsk_thread_flag(task, TIF_FORCED_TF))
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retval &= ~X86_EFLAGS_TF;
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regno >>= 2;
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switch (regno) {
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case EFL:
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/*
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* If the debugger set TF, hide it from the readout.
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*/
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retval = regs->flags;
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if (test_tsk_thread_flag(child, TIF_FORCED_TF))
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retval &= ~X86_EFLAGS_TF;
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break;
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case GS:
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retval = child->thread.gs;
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if (child == current)
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savesegment(gs, retval);
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break;
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case DS:
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case ES:
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case FS:
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case SS:
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case CS:
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retval = 0xffff;
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/* fall through */
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default:
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retval &= *pt_regs_access(regs, regno);
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}
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return retval;
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}
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static int set_flags(struct task_struct *task, unsigned long value)
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{
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struct pt_regs *regs = task_pt_regs(task);
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/*
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* If the user value contains TF, mark that
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* it was not "us" (the debugger) that set it.
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* If not, make sure it stays set if we had.
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*/
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if (value & X86_EFLAGS_TF)
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clear_tsk_thread_flag(task, TIF_FORCED_TF);
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else if (test_tsk_thread_flag(task, TIF_FORCED_TF))
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value |= X86_EFLAGS_TF;
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regs->flags = (regs->flags & ~FLAG_MASK) | (value & FLAG_MASK);
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return 0;
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}
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static int putreg(struct task_struct *child,
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unsigned long offset, unsigned long value)
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{
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switch (offset) {
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case offsetof(struct user_regs_struct, cs):
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case offsetof(struct user_regs_struct, ds):
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case offsetof(struct user_regs_struct, es):
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case offsetof(struct user_regs_struct, fs):
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case offsetof(struct user_regs_struct, gs):
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case offsetof(struct user_regs_struct, ss):
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return set_segment_reg(child, offset, value);
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case offsetof(struct user_regs_struct, flags):
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return set_flags(child, value);
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}
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*pt_regs_access(task_pt_regs(child), offset) = value;
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return 0;
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}
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static unsigned long getreg(struct task_struct *task, unsigned long offset)
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{
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switch (offset) {
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case offsetof(struct user_regs_struct, cs):
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case offsetof(struct user_regs_struct, ds):
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case offsetof(struct user_regs_struct, es):
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case offsetof(struct user_regs_struct, fs):
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case offsetof(struct user_regs_struct, gs):
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case offsetof(struct user_regs_struct, ss):
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return get_segment_reg(task, offset);
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case offsetof(struct user_regs_struct, flags):
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return get_flags(task);
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}
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return *pt_regs_access(task_pt_regs(task), offset);
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}
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/*
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* This function is trivial and will be inlined by the compiler.
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* Having it separates the implementation details of debug
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