Commit 6cc5e7ff authored by Oleg Nesterov's avatar Oleg Nesterov

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: default avatarJonathan Lebon <jlebon@redhat.com>
Signed-off-by: default avatarOleg Nesterov <oleg@redhat.com>
Reviewed-by: default avatarJim Keniston <jkenisto@us.ibm.com>
parent 8f95505b
...@@ -599,6 +599,14 @@ static int branch_setup_xol_ops(struct arch_uprobe *auprobe, struct insn *insn) ...@@ -599,6 +599,14 @@ static int branch_setup_xol_ops(struct arch_uprobe *auprobe, struct insn *insn)
branch_clear_offset(auprobe, insn); branch_clear_offset(auprobe, insn);
break; 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: default:
if (!is_cond_jmp_opcode(opc1)) if (!is_cond_jmp_opcode(opc1))
return -ENOSYS; return -ENOSYS;
......
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