Messages in this thread Patch in this message | | | Date | Mon, 06 Jun 2005 10:36:55 -0700 | From | Anil S Keshavamurthy <> | Subject | [patch 3/3] Kprobes IA64 safe register kprobe |
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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 <anil.s.keshavamurthy@intel.com> =================================================================== 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); --
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