From mboxrd@z Thu Jan 1 00:00:00 1970 From: panand@redhat.com (Pratyush Anand) Date: Mon, 12 Jan 2015 10:34:58 +0530 Subject: [RFC 8/8] ARM64: Add uprobe support In-Reply-To: <20150109175936.GB13161@redhat.com> References: <0694af6935f9c6873ef8d25ad51630a40a74a116.1420038188.git.panand@redhat.com> <20150109175936.GB13161@redhat.com> Message-ID: <54B355FA.60702@redhat.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Friday 09 January 2015 11:29 PM, Oleg Nesterov wrote: > On 12/31, Pratyush Anand wrote: >> >> +int arch_uprobe_analyze_insn(struct arch_uprobe *auprobe, struct mm_struct *mm, >> + unsigned long addr) >> +{ >> + probe_opcode_t insn; >> + >> + insn = *(probe_opcode_t *)(&auprobe->insn[0]); >> + >> + switch (arm_probe_decode_insn(insn, &auprobe->ainsn)) { >> + case INSN_REJECTED: >> + return -EINVAL; >> + >> + case INSN_GOOD_NO_SLOT: >> + auprobe->simulate = true; >> + if (auprobe->ainsn.prepare) >> + auprobe->ainsn.prepare(insn, &auprobe->ainsn); >> + break; >> + >> + case INSN_GOOD: >> + default: >> + break; >> + } >> + >> + return 0; >> +} > > forgot to mention... shouldn't it also check IS_ALIGNED(addr, AARCH64_INSN_SIZE) ? > > I do not know if unaligned insn address is valid on arm64 or not, but please AARCH64 instructions are always of fixed lenght ie 4 bytes. I do not see possibility of addr being unaligned. Please let me know, if I am missing something. > note that at least it should not cross the page boundary, set_swbp() needs to > write AARCH64_INSN_SIZE == UPROBE_SWBP_INSN bytes and it assumes that this > should fit the single page. So, again I do not see the possibility of crossing of page boundary for any instruction address. ~Pratyush