From 708de8f11c2901cc49fd7725baf4a0fbd7264e73 Mon Sep 17 00:00:00 2001 From: Anil S Keshavamurthy Date: Thu, 23 Jun 2005 00:09:34 -0700 Subject: [PATCH] [PATCH] Kprobes IA64: safe register kprobe The current kprobes does not yet handle register kprobes on some of the following kind of instruction which needs to be emulated in a special way. 1) mov r1=ip 2) chk -- Speculation check instruction This patch attempts to fail register_kprobes() when user tries to insert kprobes on the above kind of instruction. Signed-off-by: Anil S Keshavamurthy Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/ia64/kernel/kprobes.c | 45 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 45 insertions(+) diff --git a/arch/ia64/kernel/kprobes.c b/arch/ia64/kernel/kprobes.c index 51bc08bd0466..027d656664d2 100644 --- a/arch/ia64/kernel/kprobes.c +++ b/arch/ia64/kernel/kprobes.c @@ -119,6 +119,48 @@ static void update_kprobe_inst_flag(uint template, uint slot, uint major_opcode return; } +/* + * In this function we check to see if the instruction + * on which we are inserting kprobe is supported. + * Returns 0 if supported + * Returns -EINVAL if unsupported + */ +static int unsupported_inst(uint template, uint slot, uint major_opcode, + unsigned long kprobe_inst, struct kprobe *p) +{ + unsigned long addr = (unsigned long)p->addr; + + if (bundle_encoding[template][slot] == I) { + switch (major_opcode) { + case 0x0: //I_UNIT_MISC_OPCODE: + /* + * Check for Integer speculation instruction + * - Bit 33-35 to be equal to 0x1 + */ + if (((kprobe_inst >> 33) & 0x7) == 1) { + printk(KERN_WARNING + "Kprobes on speculation inst at <0x%lx> not supported\n", + addr); + return -EINVAL; + } + + /* + * IP relative mov instruction + * - Bit 27-35 to be equal to 0x30 + */ + if (((kprobe_inst >> 27) & 0x1FF) == 0x30) { + printk(KERN_WARNING + "Kprobes on \"mov r1=ip\" at <0x%lx> not supported\n", + addr); + return -EINVAL; + + } + } + } + return 0; +} + + /* * In this function we check to see if the instruction * (qp) cmpx.crel.ctype p1,p2=r2,r3 @@ -254,6 +296,9 @@ int arch_prepare_kprobe(struct kprobe *p) /* Get kprobe_inst and major_opcode from the bundle */ get_kprobe_inst(bundle, slot, &kprobe_inst, &major_opcode); + if (unsupported_inst(template, slot, major_opcode, kprobe_inst, p)) + return -EINVAL; + prepare_break_inst(template, slot, major_opcode, kprobe_inst, p); return 0; -- 2.20.1