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(unknown [219.141.235.82]) by APP-05 (Coremail) with SMTP id zQCowACnrKByhmdj7bRnCA--.7053S12; Sun, 06 Nov 2022 18:03:35 +0800 (CST) From: Chen Guokai To: paul.walmsley@sifive.com, palmer@dabbelt.com, aou@eecs.berkeley.edu, rostedt@goodmis.org, mingo@redhat.com, sfr@canb.auug.org.au Cc: linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, liaochang1@huawei.com, Chen Guokai Subject: [PATCH v4 8/8] riscv/kprobe: Patch AUIPC/JALR pair to optimize kprobe Date: Sun, 6 Nov 2022 18:03:16 +0800 Message-Id: <20221106100316.2803176-9-chenguokai17@mails.ucas.ac.cn> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20221106100316.2803176-1-chenguokai17@mails.ucas.ac.cn> References: <20221106100316.2803176-1-chenguokai17@mails.ucas.ac.cn> MIME-Version: 1.0 X-CM-TRANSID: zQCowACnrKByhmdj7bRnCA--.7053S12 X-Coremail-Antispam: 1UD129KBjvJXoW3XF1fGry3ur45uw15Cw45Jrb_yoW7CF4kpF s8G3ZxJrWYkFn2grZxAws5ur1rKwsYyay3K34DGrWfAr47Jrs8Wwnakwn8ZF15GF1Fgr13 ArnYkryruay7JFJanT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUmI14x267AKxVWrJVCq3wAFc2x0x2IEx4CE42xK8VAvwI8IcIk0 rVWrJVCq3wAFIxvE14AKwVWUJVWUGwA2048vs2IY020E87I2jVAFwI0_JF0E3s1l82xGYI kIc2x26xkF7I0E14v26ryj6s0DM28lY4IEw2IIxxk0rwA2F7IY1VAKz4vEj48ve4kI8wA2 z4x0Y4vE2Ix0cI8IcVAFwI0_Xr0_Ar1l84ACjcxK6xIIjxv20xvEc7CjxVAFwI0_Gr1j6F 4UJwA2z4x0Y4vEx4A2jsIE14v26rxl6s0DM28EF7xvwVC2z280aVCY1x0267AKxVW0oVCq 3wAac4AC62xK8xCEY4vEwIxC4wAS0I0E0xvYzxvE52x082IY62kv0487Mc02F40EFcxC0V AKzVAqx4xG6I80ewAv7VC0I7IYx2IY67AKxVWUJVWUGwAv7VC2z280aVAFwI0_Jr0_Gr1l Ox8S6xCaFVCjc4AY6r1j6r4UM4x0Y48IcxkI7VAKI48JM4x0x7Aq67IIx4CEVc8vx2IErc IFxwACI402YVCY1x02628vn2kIc2xKxwCF04k20xvY0x0EwIxGrwCFx2IqxVCFs4IE7xkE bVWUJVW8JwC20s026c02F40E14v26r1j6r18MI8I3I0E7480Y4vE14v26r106r1rMI8E67 AF67kF1VAFwI0_Jw0_GFylIxkGc2Ij64vIr41lIxAIcVC0I7IYx2IY67AKxVWUCVW8JwCI 42IY6xIIjxv20xvEc7CjxVAFwI0_Cr0_Gr1UMIIF0xvE42xK8VAvwI8IcIk0rVWUJVWUCw CI42IY6I8E87Iv67AKxVW8JVWxJwCI42IY6I8E87Iv6xkF7I0E14v26r4j6r4UJbIYCTnI WIevJa73UjIFyTuYvjfUOOzVUUUUU X-Originating-IP: [219.141.235.82] X-CM-SenderInfo: xfkh0w5xrntxyrx6ztxlovh3xfdvhtffof0/1tbiBwQCE2NnTgRK3AAAsK X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00,SPF_HELO_PASS, SPF_PASS autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1748740719760596200?= X-GMAIL-MSGID: =?utf-8?q?1748740719760596200?= From: Liao Chang From: Liao Chang The patch optimize 'EBREAK' with 'AUIPC/JALR', introduce new patching function to modify multiple instructions. Signed-off-by: Liao Chang Co-developed-by: Chen Guokai Signed-off-by: Chen Guokai --- arch/riscv/include/asm/patch.h | 1 + arch/riscv/kernel/patch.c | 22 +++++++++--- arch/riscv/kernel/probes/opt.c | 63 ++++++++++++++++++++++++++++++++-- 3 files changed, 80 insertions(+), 6 deletions(-) diff --git a/arch/riscv/include/asm/patch.h b/arch/riscv/include/asm/patch.h index 9a7d7346001e..ee31539de65f 100644 --- a/arch/riscv/include/asm/patch.h +++ b/arch/riscv/include/asm/patch.h @@ -8,5 +8,6 @@ int patch_text_nosync(void *addr, const void *insns, size_t len); int patch_text(void *addr, u32 insn); +int patch_text_batch(void *addr, const void *insn, size_t size); #endif /* _ASM_RISCV_PATCH_H */ diff --git a/arch/riscv/kernel/patch.c b/arch/riscv/kernel/patch.c index 765004b60513..02c43bb1fad3 100644 --- a/arch/riscv/kernel/patch.c +++ b/arch/riscv/kernel/patch.c @@ -15,7 +15,8 @@ struct patch_insn { void *addr; - u32 insn; + const void *insn; + size_t size; atomic_t cpu_count; }; @@ -106,8 +107,7 @@ static int patch_text_cb(void *data) if (atomic_inc_return(&patch->cpu_count) == num_online_cpus()) { ret = - patch_text_nosync(patch->addr, &patch->insn, - GET_INSN_LENGTH(patch->insn)); + patch_text_nosync(patch->addr, patch->insn, patch->size); atomic_inc(&patch->cpu_count); } else { while (atomic_read(&patch->cpu_count) <= num_online_cpus()) @@ -123,7 +123,8 @@ int patch_text(void *addr, u32 insn) { struct patch_insn patch = { .addr = addr, - .insn = insn, + .insn = &insn, + .size = GET_INSN_LENGTH(insn), .cpu_count = ATOMIC_INIT(0), }; @@ -131,3 +132,17 @@ int patch_text(void *addr, u32 insn) &patch, cpu_online_mask); } NOKPROBE_SYMBOL(patch_text); + +int patch_text_batch(void *addr, const void *insn, size_t size) +{ + struct patch_insn patch = { + .addr = addr, + .insn = insn, + .size = size, + .cpu_count = ATOMIC_INIT(0), + }; + + return stop_machine_cpuslocked(patch_text_cb, &patch, cpu_online_mask); +} + +NOKPROBE_SYMBOL(patch_text_batch); diff --git a/arch/riscv/kernel/probes/opt.c b/arch/riscv/kernel/probes/opt.c index 77248ed7d4e8..947bc015da7e 100644 --- a/arch/riscv/kernel/probes/opt.c +++ b/arch/riscv/kernel/probes/opt.c @@ -448,11 +448,19 @@ static bool can_optimize(unsigned long paddr, struct optimized_kprobe *op) int arch_prepared_optinsn(struct arch_optimized_insn *optinsn) { - return 0; + return optinsn->length; } int arch_check_optimized_kprobe(struct optimized_kprobe *op) { + unsigned long i; + struct kprobe *p; + + for (i = RVC_INSN_LEN; i < op->optinsn.length; i += RVC_INSN_LEN) { + p = get_kprobe(op->kp.addr + i); + if (p && !kprobe_disabled(p)) + return -EEXIST; + } return 0; } @@ -521,23 +529,74 @@ int arch_prepare_optimized_kprobe(struct optimized_kprobe *op, void arch_remove_optimized_kprobe(struct optimized_kprobe *op) { + if (op->optinsn.insn) { + free_optinsn_slot(op->optinsn.insn, 1); + op->optinsn.insn = NULL; + op->optinsn.length = 0; + } } void arch_optimize_kprobes(struct list_head *oplist) { + long offs; + kprobe_opcode_t insn[3]; + struct optimized_kprobe *op, *tmp; + + list_for_each_entry_safe(op, tmp, oplist, list) { + WARN_ON(kprobe_disabled(&op->kp)); + + /* Backup instructions which will be replaced by jump address */ + memcpy(op->optinsn.copied_insn, + DETOUR_ADDR(op->kp.addr, GET_INSN_LENGTH(op->kp.opcode)), + op->optinsn.length - GET_INSN_LENGTH(op->kp.opcode)); + + /* + * After patch, it should be: + * auipc free_register, %hi(detour_buffer) + * jalr free_register, free_register, %lo(detour_buffer) + * where free_register will eventually save the return address + */ + offs = (unsigned long)op->optinsn.insn - + (unsigned long)op->kp.addr; + insn[0] = rv_auipc(op->optinsn.rd, (offs + (1 << 11)) >> 12); + insn[1] = rv_jalr(op->optinsn.rd, op->optinsn.rd, offs & 0xFFF); + /* For 3 RVC + 1 RVI scenario, need C.NOP for padding */ + if (op->optinsn.length > 2 * RVI_INSN_LEN) + insn[2] = rvc_addi(0, 0); + + patch_text_batch(op->kp.addr, insn, op->optinsn.length); + if (memcmp(op->kp.addr, insn, op->optinsn.length)) + continue; + + list_del_init(&op->list); + } } void arch_unoptimize_kprobes(struct list_head *oplist, struct list_head *done_list) { + struct optimized_kprobe *op, *tmp; + + list_for_each_entry_safe(op, tmp, oplist, list) { + arch_unoptimize_kprobe(op); + list_move(&op->list, done_list); + } } void arch_unoptimize_kprobe(struct optimized_kprobe *op) { + kprobe_opcode_t buf[MAX_COPIED_INSN]; + unsigned long offset = GET_INSN_LENGTH(op->kp.opcode); + + buf[0] = (offset == RVI_INSN_LEN) ? __BUG_INSN_32 : __BUG_INSN_16; + memcpy(DETOUR_ADDR(buf, offset), op->optinsn.copied_insn, + op->optinsn.length - offset); + patch_text_batch(op->kp.addr, buf, op->optinsn.length); } int arch_within_optimized_kprobe(struct optimized_kprobe *op, kprobe_opcode_t *addr) { - return 0; + return (op->kp.addr <= addr && + op->kp.addr + op->optinsn.length > addr); }