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

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 <oleg@redhat.com>
Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Reviewed-by: Jim Keniston <jkenisto@us.ibm.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>

1 files changed, 14 insertions, 16 deletions

diff --git a/arch/x86/kernel/uprobes.c b/arch/x86/kernel/uprobes.c
index c52c30fa7871..3bb4198aa588 100644
--- a/arch/x86/kernel/uprobes.c
+++ b/arch/x86/kernel/uprobes.c
@@ -474,19 +474,18 @@ 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;
 }
 
@@ -560,22 +559,13 @@ 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
@@ -586,6 +576,14 @@ 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;
 }