diff options
| author | Maneesh Soni <manesoni@cisco.com> | 2011-11-08 11:35:35 (GMT) |
|---|---|---|
| committer | Ralf Baechle <ralf@linux-mips.org> | 2011-12-07 22:04:03 (GMT) |
| commit | 9233c1ee71bdd3c8a918c8e17026cf3f7d99c90b (patch) | |
| tree | 9c653068e63cda169569796ce721af418670db5d /arch/mips/kernel | |
| parent | 41dde781f50c39cddc8032fc04d6a7d538237737 (diff) | |
| download | linux-9233c1ee71bdd3c8a918c8e17026cf3f7d99c90b.tar.xz | |
MIPS Kprobes: Deny probes on ll/sc instructions
As ll/sc instruction are for atomic read-modify-write operations, allowing
probes on top of these insturctions is a bad idea.
Signed-off-by: Victor Kamensky <kamensky@cisco.com>
Signed-off-by: Maneesh Soni <manesoni@cisco.com>
Cc: David Daney <david.daney@cavium.com>
Cc: ananth@in.ibm.com
Cc: linux-kernel@vger.kernel.org
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/2912/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Diffstat (limited to 'arch/mips/kernel')
| -rw-r--r-- | arch/mips/kernel/kprobes.c | 31 |
1 files changed, 31 insertions, 0 deletions
diff --git a/arch/mips/kernel/kprobes.c b/arch/mips/kernel/kprobes.c index 9fb1876..0ab1a5f 100644 --- a/arch/mips/kernel/kprobes.c +++ b/arch/mips/kernel/kprobes.c @@ -113,6 +113,30 @@ insn_ok: return 0; } +/* + * insn_has_ll_or_sc function checks whether instruction is ll or sc + * one; putting breakpoint on top of atomic ll/sc pair is bad idea; + * so we need to prevent it and refuse kprobes insertion for such + * instructions; cannot do much about breakpoint in the middle of + * ll/sc pair; it is upto user to avoid those places + */ +static int __kprobes insn_has_ll_or_sc(union mips_instruction insn) +{ + int ret = 0; + + switch (insn.i_format.opcode) { + case ll_op: + case lld_op: + case sc_op: + case scd_op: + ret = 1; + break; + default: + break; + } + return ret; +} + int __kprobes arch_prepare_kprobe(struct kprobe *p) { union mips_instruction insn; @@ -121,6 +145,13 @@ int __kprobes arch_prepare_kprobe(struct kprobe *p) insn = p->addr[0]; + if (insn_has_ll_or_sc(insn)) { + pr_notice("Kprobes for ll and sc instructions are not" + "supported\n"); + ret = -EINVAL; + goto out; + } + if (insn_has_delayslot(insn)) { pr_notice("Kprobes for branch and jump instructions are not" "supported\n"); |