[PATCH 6/7] uprobes/x86: move the UPROBE_FIX_{RIP,IP,CALL} code at the end of pre/post hooks

[Oleg Nesterov]

No functional changes. Preparation to simplify the review of the next
change. Just reorder the code in arch_uprobe_pre/post_xol() functions
so that UPROBE_FIX_{RIP_*,IP,CALL} logic goes to the end.

Also change arch_uprobe_pre_xol() to use utask instead of autask, to
make the code more symmetrical with arch_uprobe_post_xol().

Signed-off-by: Oleg Nesterov <o...@redhat.com>
---
 arch/x86/kernel/uprobes.c |   30 ++++++++++++++----------------
 1 files changed, 14 insertions(+), 16 deletions(-)

diff --git a/arch/x86/kernel/uprobes.c b/arch/x86/kernel/uprobes.c
index e8d7b38..7dd65dc 100644
--- a/arch/x86/kernel/uprobes.c
+++ b/arch/x86/kernel/uprobes.c
@@ -472,19 +472,18 @@ int arch_uprobe_analyze_insn(struct arch_uprobe *auprobe, 
struct mm_struct *mm,
  */
 int arch_uprobe_pre_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)
 {
-       struct arch_uprobe_task *autask;
+       struct uprobe_task *utask = current->utask;
 
-       autask = &current->utask->autask;
-       autask->saved_trap_nr = current->thread.trap_nr;
+       regs->ip = utask->xol_vaddr;
+       utask->autask.saved_trap_nr = current->thread.trap_nr;
        current->thread.trap_nr = UPROBE_TRAP_NR;
-       regs->ip = current->utask->xol_vaddr;
-       pre_xol_rip_insn(auprobe, regs, autask);
 
-       autask->saved_tf = !!(regs->flags & X86_EFLAGS_TF);
+       utask->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);
 
+       pre_xol_rip_insn(auprobe, regs, &utask->autask);
        return 0;
 }
 
@@ -558,22 +557,13 @@ bool arch_uprobe_xol_was_trapped(struct task_struct *t)
  */
 int arch_uprobe_post_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)
 {
-       struct uprobe_task *utask;
+       struct uprobe_task *utask = current->utask;
        long correction;
        int result = 0;
 
        WARN_ON_ONCE(current->thread.trap_nr != UPROBE_TRAP_NR);
 
-       utask = current->utask;
        current->thread.trap_nr = utask->autask.saved_trap_nr;
-       correction = (long)(utask->vaddr - utask->xol_vaddr);
-       handle_riprel_post_xol(auprobe, regs, &correction);
-       if (auprobe->fixups & UPROBE_FIX_IP)
-               regs->ip += correction;
-
-       if (auprobe->fixups & UPROBE_FIX_CALL)
-               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
@@ -584,6 +574,14 @@ int arch_uprobe_post_xol(struct arch_uprobe *auprobe, 
struct pt_regs *regs)
        else if (!(auprobe->fixups & UPROBE_FIX_SETF))
                regs->flags &= ~X86_EFLAGS_TF;
 
+       correction = (long)(utask->vaddr - utask->xol_vaddr);
+       handle_riprel_post_xol(auprobe, regs, &correction);
+       if (auprobe->fixups & UPROBE_FIX_IP)
+               regs->ip += correction;
+
+       if (auprobe->fixups & UPROBE_FIX_CALL)
+               result = adjust_ret_addr(regs->sp, correction);
+
        return result;
 }
 
-- 
1.5.5.1

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