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    Subject[PATCH v3 15/15] uprobes/x86: Emulate relative conditional "near" jmp's
    Change branch_setup_xol_ops() to simply use opc1 = OPCODE2(insn) - 0x10
    if OPCODE1() == 0x0f; this matches the "short" jmp which checks the same
    condition.

    Thanks to lib/insn.c, it does the rest correctly. branch->ilen/offs are
    correct no matter if this jmp is "near" or "short".

    Reported-by: Jonathan Lebon <jlebon@redhat.com>
    Signed-off-by: Oleg Nesterov <oleg@redhat.com>
    Reviewed-by: Jim Keniston <jkenisto@us.ibm.com>
    ---
    arch/x86/kernel/uprobes.c | 8 ++++++++
    1 files changed, 8 insertions(+), 0 deletions(-)

    diff --git a/arch/x86/kernel/uprobes.c b/arch/x86/kernel/uprobes.c
    index b5f2fa4..d7e9d04 100644
    --- a/arch/x86/kernel/uprobes.c
    +++ b/arch/x86/kernel/uprobes.c
    @@ -599,6 +599,14 @@ static int branch_setup_xol_ops(struct arch_uprobe *auprobe, struct insn *insn)
    branch_clear_offset(auprobe, insn);
    break;

    + case 0x0f:
    + if (insn->opcode.nbytes != 2)
    + return -ENOSYS;
    + /*
    + * If it is a "near" conditional jmp, OPCODE2() - 0x10 matches
    + * OPCODE1() of the "short" jmp which checks the same condition.
    + */
    + opc1 = OPCODE2(insn) - 0x10;
    default:
    if (!is_cond_jmp_opcode(opc1))
    return -ENOSYS;
    --
    1.5.5.1


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