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[PATCH] 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>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Anil S Keshavamurthy 2005-06-23 00:09:34 -07:00 committed by Linus Torvalds
parent 1674eafcbd
commit 708de8f11c
1 changed files with 45 additions and 0 deletions
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45
arch/ia64/kernel/kprobes.c
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@ -119,6 +119,48 @@ static void update_kprobe_inst_flag(uint template, uint slot, uint major_opcode
return; 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 * In this function we check to see if the instruction
* (qp) cmpx.crel.ctype p1,p2=r2,r3 * (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 and major_opcode from the bundle */
get_kprobe_inst(bundle, slot, &kprobe_inst, &major_opcode); 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); prepare_break_inst(template, slot, major_opcode, kprobe_inst, p);
return 0; return 0;