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uprobes/x86: Cleanup the single-stepping code

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No functional changes.

Now that default arch_uprobe_enable/disable_step() helpers do nothing,
x86 has no reason to reimplement them. Change arch_uprobe_*_xol() hooks
to do the necessary work and remove the x86-specific hooks.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
This commit is contained in:
Oleg Nesterov 2012-10-28 17:57:30 +01:00
parent 65b2c8f0e5
commit 4dc316c645
1 changed files with 19 additions and 35 deletions

54
arch/x86/kernel/uprobes.c

@ -478,6 +478,11 @@ int arch_uprobe_pre_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)
regs->ip = current->utask->xol_vaddr; regs->ip = current->utask->xol_vaddr;
pre_xol_rip_insn(auprobe, regs, autask); pre_xol_rip_insn(auprobe, regs, autask);
autask->saved_tf = !!(regs->flags & X86_EFLAGS_TF);
regs->flags |= X86_EFLAGS_TF;
if (test_tsk_thread_flag(current, TIF_BLOCKSTEP))
set_task_blockstep(current, false);
return 0; return 0;
} }
@ -603,6 +608,16 @@ int arch_uprobe_post_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)
if (auprobe->fixups & UPROBE_FIX_CALL) if (auprobe->fixups & UPROBE_FIX_CALL)
result = adjust_ret_addr(regs->sp, correction); result = adjust_ret_addr(regs->sp, correction);
/*
* arch_uprobe_pre_xol() doesn't save the state of TIF_BLOCKSTEP
* so we can get an extra SIGTRAP if we do not clear TF. We need
* to examine the opcode to make it right.
*/
if (utask->autask.saved_tf)
send_sig(SIGTRAP, current, 0);
else if (!(auprobe->fixups & UPROBE_FIX_SETF))
regs->flags &= ~X86_EFLAGS_TF;
return result; return result;
} }
@ -647,6 +662,10 @@ void arch_uprobe_abort_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)
current->thread.trap_nr = utask->autask.saved_trap_nr; current->thread.trap_nr = utask->autask.saved_trap_nr;
handle_riprel_post_xol(auprobe, regs, NULL); handle_riprel_post_xol(auprobe, regs, NULL);
instruction_pointer_set(regs, utask->vaddr); instruction_pointer_set(regs, utask->vaddr);
/* clear TF if it was set by us in arch_uprobe_pre_xol() */
if (!utask->autask.saved_tf)
regs->flags &= ~X86_EFLAGS_TF;
} }
/* /*
@ -676,38 +695,3 @@ bool arch_uprobe_skip_sstep(struct arch_uprobe *auprobe, struct pt_regs *regs)
send_sig(SIGTRAP, current, 0); send_sig(SIGTRAP, current, 0);
return ret; return ret;
} }
void arch_uprobe_enable_step(struct arch_uprobe *auprobe)
{
struct task_struct *task = current;
struct arch_uprobe_task *autask = &task->utask->autask;
struct pt_regs *regs = task_pt_regs(task);
autask->saved_tf = !!(regs->flags & X86_EFLAGS_TF);
regs->flags |= X86_EFLAGS_TF;
if (test_tsk_thread_flag(task, TIF_BLOCKSTEP))
set_task_blockstep(task, false);
}
void arch_uprobe_disable_step(struct arch_uprobe *auprobe)
{
struct task_struct *task = current;
struct arch_uprobe_task *autask = &task->utask->autask;
bool trapped = (task->utask->state == UTASK_SSTEP_TRAPPED);
struct pt_regs *regs = task_pt_regs(task);
/*
* The state of TIF_BLOCKSTEP was not saved so we can get an extra
* SIGTRAP if we do not clear TF. We need to examine the opcode to
* make it right.
*/
if (unlikely(trapped)) {
if (!autask->saved_tf)
regs->flags &= ~X86_EFLAGS_TF;
} else {
if (autask->saved_tf)
send_sig(SIGTRAP, task, 0);
else if (!(auprobe->fixups & UPROBE_FIX_SETF))
regs->flags &= ~X86_EFLAGS_TF;
}
}