From mboxrd@z Thu Jan 1 00:00:00 1970 From: Anil S Keshavamurthy Date: Mon, 06 Jun 2005 17:36:55 +0000 Subject: [patch 3/3] Kprobes IA64 safe register kprobe Message-Id: <20050606174059.177392000@csdlinux-2.jf.intel.com> List-Id: References: <20050606173652.059047000@csdlinux-2.jf.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: akpm@osdl.org Cc: linux-kernel@vger.kernel.org, linux-ia64@vger.kernel.org, systemtap@sources.redhat.com, rusty.lynch@intel.com, davidm@napali.hpl.hp.com, alen.brunelle@hp.com, anil.s.keshavamurthy@intel.com 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 ================================= arch/ia64/kernel/kprobes.c | 45 +++++++++++++++++++++++++++++++++++++++++++++ 1 files changed, 45 insertions(+) Index: linux-2.6.12-rc5/arch/ia64/kernel/kprobes.c =================================--- linux-2.6.12-rc5.orig/arch/ia64/kernel/kprobes.c +++ linux-2.6.12-rc5/arch/ia64/kernel/kprobes.c @@ -98,6 +98,48 @@ static inline void set_current_kprobe(st current_kprobe = p; } +/* + * 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 * is IP relative instruction and update the kprobe @@ -270,6 +312,9 @@ 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); --