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[180.150.65.4]) by smtp.gmail.com with ESMTPSA id k4sm465676pgg.88.2020.05.05.20.48.53 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 05 May 2020 20:49:07 -0700 (PDT) From: Jordan Niethe To: linuxppc-dev@lists.ozlabs.org Subject: [PATCH v8 27/30] powerpc/kprobes: Don't allow breakpoints on suffixes Date: Wed, 6 May 2020 13:40:47 +1000 Message-Id: <20200506034050.24806-28-jniethe5@gmail.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200506034050.24806-1-jniethe5@gmail.com> References: <20200506034050.24806-1-jniethe5@gmail.com> X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: alistair@popple.id.au, npiggin@gmail.com, bala24@linux.ibm.com, naveen.n.rao@linux.vnet.ibm.com, Jordan Niethe , dja@axtens.net Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" Do not allow inserting breakpoints on the suffix of a prefix instruction in kprobes. Signed-off-by: Jordan Niethe --- v8: Add this back from v3 --- arch/powerpc/kernel/kprobes.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/arch/powerpc/kernel/kprobes.c b/arch/powerpc/kernel/kprobes.c index 33d54b091c70..227510df8c55 100644 --- a/arch/powerpc/kernel/kprobes.c +++ b/arch/powerpc/kernel/kprobes.c @@ -106,7 +106,9 @@ kprobe_opcode_t *kprobe_lookup_name(const char *name, unsigned int offset) int arch_prepare_kprobe(struct kprobe *p) { int ret = 0; + struct kprobe *prev; struct ppc_inst insn = ppc_inst_read((struct ppc_inst *)p->addr); + struct ppc_inst prefix = ppc_inst_read((struct ppc_inst *)(p->addr - 1)); if ((unsigned long)p->addr & 0x03) { printk("Attempt to register kprobe at an unaligned address\n"); @@ -114,6 +116,17 @@ int arch_prepare_kprobe(struct kprobe *p) } else if (IS_MTMSRD(insn) || IS_RFID(insn) || IS_RFI(insn)) { printk("Cannot register a kprobe on rfi/rfid or mtmsr[d]\n"); ret = -EINVAL; + } else if (ppc_inst_prefixed(prefix)) { + printk("Cannot register a kprobe on the second word of prefixed instruction\n"); + ret = -EINVAL; + } + preempt_disable(); + prev = get_kprobe(p->addr - 1); + preempt_enable_no_resched(); + if (prev && + ppc_inst_prefixed(ppc_inst_read((struct ppc_inst *)prev->ainsn.insn))) { + printk("Cannot register a kprobe on the second word of prefixed instruction\n"); + ret = -EINVAL; } /* insn must be on a special executable page on ppc64. This is -- 2.17.1