uprobes/x86: Move UPROBE_FIX_SETF logic from arch_uprobe_post_xol() to default_post_xol_op()
UPROBE_FIX_SETF is only needed to handle "popf" correctly but it is processed by the generic arch_uprobe_post_xol() code. This doesn't allows us to make ->fixups private for default_xol_ops. 1 Change default_post_xol_op(UPROBE_FIX_SETF) to set ->saved_tf = T. "popf" always reads the flags from stack, it doesn't matter if TF was set or not before single-step. Ignoring the naming, this is even more logical, "saved_tf" means "owned by application" and we do not own this flag after "popf". 2. Change arch_uprobe_post_xol() to save ->saved_tf into the local "bool send_sigtrap" before ->post_xol(). 3. Change arch_uprobe_post_xol() to ignore UPROBE_FIX_SETF and just check ->saved_tf after ->post_xol(). With this patch ->fixups and ->rip_rela_target_address are only used by default_xol_ops hooks, we are ready to remove them from the common part of arch_uprobe. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Reviewed-by: Jim Keniston <jkenisto@us.ibm.com>
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@ -441,6 +441,9 @@ static int default_post_xol_op(struct arch_uprobe *auprobe, struct pt_regs *regs
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return -ERESTART;
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return -ERESTART;
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}
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}
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}
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}
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/* popf; tell the caller to not touch TF */
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if (auprobe->fixups & UPROBE_FIX_SETF)
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utask->autask.saved_tf = true;
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return 0;
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return 0;
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}
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}
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@ -757,15 +760,15 @@ bool arch_uprobe_xol_was_trapped(struct task_struct *t)
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int arch_uprobe_post_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)
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int arch_uprobe_post_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)
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{
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{
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struct uprobe_task *utask = current->utask;
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struct uprobe_task *utask = current->utask;
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bool send_sigtrap = utask->autask.saved_tf;
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int err = 0;
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WARN_ON_ONCE(current->thread.trap_nr != UPROBE_TRAP_NR);
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WARN_ON_ONCE(current->thread.trap_nr != UPROBE_TRAP_NR);
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current->thread.trap_nr = utask->autask.saved_trap_nr;
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current->thread.trap_nr = utask->autask.saved_trap_nr;
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if (auprobe->ops->post_xol) {
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if (auprobe->ops->post_xol) {
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int err = auprobe->ops->post_xol(auprobe, regs);
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err = auprobe->ops->post_xol(auprobe, regs);
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if (err) {
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if (err) {
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if (!utask->autask.saved_tf)
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regs->flags &= ~X86_EFLAGS_TF;
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/*
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/*
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* Restore ->ip for restart or post mortem analysis.
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* Restore ->ip for restart or post mortem analysis.
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* ->post_xol() must not return -ERESTART unless this
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* ->post_xol() must not return -ERESTART unless this
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@ -773,8 +776,8 @@ int arch_uprobe_post_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)
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*/
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*/
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regs->ip = utask->vaddr;
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regs->ip = utask->vaddr;
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if (err == -ERESTART)
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if (err == -ERESTART)
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return 0;
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err = 0;
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return err;
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send_sigtrap = false;
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}
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}
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}
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}
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/*
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/*
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@ -782,12 +785,13 @@ int arch_uprobe_post_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)
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* so we can get an extra SIGTRAP if we do not clear TF. We need
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* so we can get an extra SIGTRAP if we do not clear TF. We need
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* to examine the opcode to make it right.
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* to examine the opcode to make it right.
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*/
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*/
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if (utask->autask.saved_tf)
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if (send_sigtrap)
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send_sig(SIGTRAP, current, 0);
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send_sig(SIGTRAP, current, 0);
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else if (!(auprobe->fixups & UPROBE_FIX_SETF))
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if (!utask->autask.saved_tf)
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regs->flags &= ~X86_EFLAGS_TF;
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regs->flags &= ~X86_EFLAGS_TF;
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return 0;
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return err;
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}
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}
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/* callback routine for handling exceptions. */
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/* callback routine for handling exceptions. */
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