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    Subject[PATCH v3 07/15] uprobes/x86: Conditionalize the usage of handle_riprel_insn()
    arch_uprobe_analyze_insn() calls handle_riprel_insn() at the start,
    but only "0xff" and "default" cases need the UPROBE_FIX_RIP_ logic.
    Move the callsite into "default" case and change the "0xff" case to
    fall-through.

    We are going to add the various hooks to handle the rip-relative
    jmp/call instructions (and more), we need this change to enforce the
    fact that the new code can not conflict with is_riprel_insn() logic
    which, after this change, can only be used by default_xol_ops.

    Note: arch_uprobe_abort_xol() still calls handle_riprel_post_xol()
    directly. This is fine unless another _xol_ops we may add later will
    need to reuse "UPROBE_FIX_RIP_AX|UPROBE_FIX_RIP_CX" bits in ->fixup.
    In this case we can add uprobe_xol_ops->abort() hook, which (perhaps)
    we will need anyway in the long term.

    Signed-off-by: Oleg Nesterov <oleg@redhat.com>
    Reviewed-by: Jim Keniston <jkenisto@us.ibm.com>
    Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
    ---
    arch/x86/kernel/uprobes.c | 6 ++----
    1 files changed, 2 insertions(+), 4 deletions(-)

    diff --git a/arch/x86/kernel/uprobes.c b/arch/x86/kernel/uprobes.c
    index 6ba6705..f4b436b 100644
    --- a/arch/x86/kernel/uprobes.c
    +++ b/arch/x86/kernel/uprobes.c
    @@ -482,8 +482,6 @@ int arch_uprobe_analyze_insn(struct arch_uprobe *auprobe, struct mm_struct *mm,
    * and annotate arch_uprobe->fixups accordingly. To start with, ->fixups
    * is either zero or it reflects rip-related fixups.
    */
    - handle_riprel_insn(auprobe, &insn);
    -
    switch (OPCODE1(&insn)) {
    case 0x9d: /* popf */
    auprobe->fixups |= UPROBE_FIX_SETF;
    @@ -512,9 +510,9 @@ int arch_uprobe_analyze_insn(struct arch_uprobe *auprobe, struct mm_struct *mm,
    case 4: case 5: /* jmp or ljmp, indirect */
    fix_ip = false;
    }
    - break;
    + /* fall through */
    default:
    - break;
    + handle_riprel_insn(auprobe, &insn);
    }

    if (fix_ip)
    --
    1.5.5.1


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