From patchwork Sat Dec 24 11:43:15 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Xim X-Patchwork-Id: 13081361 X-Patchwork-Delegate: palmer@dabbelt.com Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 3C6E2C4332F for ; Sat, 24 Dec 2022 15:21:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=wiBgUXcbILv+AApX34fsPEhzsbYXyZJP+w+BqojEkgM=; b=hMFNeeddrzFXAw oxT30wcb+lLEjJP4J0JN7R7OCN55PvqngHYSxJWRFgqQ2372vxBtm8ACfim70NX1nhH+axQ8vEasx +Fmk4vbE3xYBdmn5C9KsrHzl67MPNOJ5XcrICsKQg5LHHbUK1SEjYApc8XYuur3rP5jZ8BnAwXOwq v3EK39cvP89eD3BUBnKk9nmpvW/sPr3Zm4VzdhOCo+x4xKoerHxNtfS47LP0OWf1JH5Qb9N7ZL3KG KBKZ4fducA4TOFyYMQub7zaDk+ROX3myHRu03o0vG8qu2JV718UOKib257hfNrdv90xJjH97KBMu6 a/2WAQHFY2ln1elawKlA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1p96L6-0012W5-Fz; Sat, 24 Dec 2022 15:21:32 +0000 Received: from smtp23.cstnet.cn ([159.226.251.23] helo=cstnet.cn) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1p92wO-00H5ug-L1 for linux-riscv@lists.infradead.org; Sat, 24 Dec 2022 11:43:53 +0000 Received: from cgk-Precision-3650-Tower.. (unknown [219.141.235.82]) by APP-03 (Coremail) with SMTP id rQCowABXXpbf5aZj9dVkCA--.18955S13; Sat, 24 Dec 2022 19:43:29 +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 , =?utf-8?b?QmrDtnJuIFTDtnBlbA==?= Subject: [PATCH v5 9/9] riscv/kprobe: Search free registers from unused caller-saved ones Date: Sat, 24 Dec 2022 19:43:15 +0800 Message-Id: <20221224114315.850130-10-chenguokai17@mails.ucas.ac.cn> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20221224114315.850130-1-chenguokai17@mails.ucas.ac.cn> References: <20221224114315.850130-1-chenguokai17@mails.ucas.ac.cn> MIME-Version: 1.0 X-CM-TRANSID: rQCowABXXpbf5aZj9dVkCA--.18955S13 X-Coremail-Antispam: 1UD129KBjvJXoWxtF48Kw45tr17Kr4UGr1xZrb_yoW3uw1xpF sxGw4FvrWUJa4kurZrAw1kGr4fKrs8Kr40vFyUtFWSqr4aq39Ivayv93W3Xr1DtF40vr4x ArW5Cry8urW3AFJanT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUQa14x267AKxVWrJVCq3wAFc2x0x2IEx4CE42xK8VAvwI8IcIk0 rVWrJVCq3wAFIxvE14AKwVWUJVWUGwA2048vs2IY020E87I2jVAFwI0_JF0E3s1l82xGYI kIc2x26xkF7I0E14v26ryj6s0DM28lY4IEw2IIxxk0rwA2F7IY1VAKz4vEj48ve4kI8wA2 z4x0Y4vE2Ix0cI8IcVAFwI0_Xr0_Ar1l84ACjcxK6xIIjxv20xvEc7CjxVAFwI0_Gr1j6F 4UJwA2z4x0Y4vEx4A2jsIE14v26F4UJVW0owA2z4x0Y4vEx4A2jsIEc7CjxVAFwI0_Cr1j 6rxdM2vYz4IE04k24VAvwVAKI4IrM2AIxVAIcxkEcVAq07x20xvEncxIr21l5I8CrVACY4 xI64kE6c02F40Ex7xfMcIj6xIIjxv20xvE14v26r1j6r18McIj6I8E87Iv67AKxVWUJVW8 JwAm72CE4IkC6x0Yz7v_Jr0_Gr1lF7xvr2IYc2Ij64vIr41lF7I21c0EjII2zVCS5cI20V AGYxC7M4IIrI8v6xkF7I0E8cxan2IY04v7MxkIecxEwVAFwVW8KwCF04k20xvY0x0EwIxG rwCFx2IqxVCFs4IE7xkEbVWUJVW8JwC20s026c02F40E14v26r1j6r18MI8I3I0E7480Y4 vE14v26r106r1rMI8E67AF67kF1VAFwI0_Jw0_GFylIxkGc2Ij64vIr41lIxAIcVC0I7IY x2IY67AKxVWUCVW8JwCI42IY6xIIjxv20xvEc7CjxVAFwI0_Gr1j6F4UJwCI42IY6xAIw2 0EY4v20xvaj40_Jr0_JF4lIxAIcVC2z280aVAFwI0_Jr0_Gr1lIxAIcVC2z280aVCY1x02 67AKxVW8Jr0_Cr1UYxBIdaVFxhVjvjDU0xZFpf9x0JUSApnUUUUU= X-Originating-IP: [219.141.235.82] X-CM-SenderInfo: xfkh0w5xrntxyrx6ztxlovh3xfdvhtffof0/1tbiAwgKE2OmnOhnMQAAs1 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20221224_034349_159886_F20323EB X-CRM114-Status: GOOD ( 18.34 ) X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org This patch further allows optprobe to use caller-saved registers that is not used across the function being optimized as free registers. Signed-off-by: Chen Guokai Co-developed-by: Liao Chang Signed-off-by: Liao Chang Reported-by: Björn Töpel --- arch/riscv/include/asm/kprobes.h | 1 + arch/riscv/kernel/probes/decode-insn.h | 5 + arch/riscv/kernel/probes/opt.c | 121 ++++++++++++++++++++++--- 3 files changed, 112 insertions(+), 15 deletions(-) diff --git a/arch/riscv/include/asm/kprobes.h b/arch/riscv/include/asm/kprobes.h index e40c837d0a1d..7fecec799077 100644 --- a/arch/riscv/include/asm/kprobes.h +++ b/arch/riscv/include/asm/kprobes.h @@ -86,6 +86,7 @@ struct arch_optimized_insn { kprobe_opcode_t *insn; unsigned long length; int rd; + u32 free_reg; }; #endif /* CONFIG_OPTPROBES */ diff --git a/arch/riscv/kernel/probes/decode-insn.h b/arch/riscv/kernel/probes/decode-insn.h index 785b023a62ea..907b951f2c86 100644 --- a/arch/riscv/kernel/probes/decode-insn.h +++ b/arch/riscv/kernel/probes/decode-insn.h @@ -13,6 +13,11 @@ enum probe_insn { INSN_GOOD, }; +#define NRREG 32 +#define ALL_REG_OCCUPIED 0xffffffffu +/* If a register is not caller-saved, its corresponding bit is set */ +#define NON_CALLER_SAVED_MASK 0xffc031d + enum probe_insn __kprobes riscv_probe_decode_insn(probe_opcode_t *addr, struct arch_probe_insn *asi); diff --git a/arch/riscv/kernel/probes/opt.c b/arch/riscv/kernel/probes/opt.c index 1c0e9d218f6f..884e77d2df4c 100644 --- a/arch/riscv/kernel/probes/opt.c +++ b/arch/riscv/kernel/probes/opt.c @@ -12,6 +12,7 @@ #include #include #include +#include #include "simulate-insn.h" #include "decode-insn.h" @@ -130,7 +131,7 @@ static void prepare_detour_buffer(kprobe_opcode_t *code, kprobe_opcode_t *slot, * as a destination register before any branch or jump instruction. */ static void find_register(unsigned long start, unsigned long end, - unsigned long *write, unsigned long *read) + unsigned long *write, unsigned long *read) { kprobe_opcode_t insn; unsigned long addr, offset = 0UL; @@ -390,16 +391,99 @@ static int search_copied_insn(unsigned long paddr, struct optimized_kprobe *op) return 0; } +static void update_free_reg(unsigned long addr, uint32_t *used_reg) +{ + kprobe_opcode_t insn = *(kprobe_opcode_t *)addr; + unsigned long offset = GET_INSN_LENGTH(insn); + +#ifdef CONFIG_RISCV_ISA_C + if (offset == RVI_INSN_LEN) + goto is_rvi; + + insn &= __COMPRESSED_INSN_MASK; + if (riscv_insn_is_c_jal(insn)) { + *used_reg |= 1 << 1; + } else if (riscv_insn_is_c_jr(insn)) { + *used_reg |= 1 << rvc_r_rs1(insn); + } else if (riscv_insn_is_c_jalr(insn)) { + *used_reg |= 1 << rvc_r_rs1(insn); + } else if (riscv_insn_is_c_beqz(insn) || riscv_insn_is_c_bnez(insn)) { + *used_reg |= 1 << rvc_b_rs(insn); + } else if (riscv_insn_is_c_sub(insn) || riscv_insn_is_c_subw(insn)) { + *used_reg |= 1 << rvc_a_rs1(insn); + *used_reg |= 1 << rvc_a_rs2(insn); + } else if (riscv_insn_is_c_sq(insn) || riscv_insn_is_c_sw(insn) || + riscv_insn_is_c_sd(insn)) { + *used_reg |= 1 << rvc_s_rs1(insn); + *used_reg |= 1 << rvc_s_rs2(insn); + } else if (riscv_insn_is_c_addi16sp(insn) || riscv_insn_is_c_addi(insn) || + riscv_insn_is_c_addiw(insn) || + riscv_insn_is_c_slli(insn)) { + *used_reg |= 1 << rvc_i_rs1(insn); + } else if (riscv_insn_is_c_sri(insn) || + riscv_insn_is_c_andi(insn)) { + *used_reg |= 1 << rvc_b_rs(insn); + } else if (riscv_insn_is_c_sqsp(insn) || riscv_insn_is_c_swsp(insn) || + riscv_insn_is_c_sdsp(insn)) { + *used_reg |= 1 << rvc_ss_rs2(insn); + *used_reg |= 1 << 2; + } else if (riscv_insn_is_c_mv(insn)) { + *used_reg |= 1 << rvc_r_rs2(insn); + } else if (riscv_insn_is_c_addi4spn(insn)) { + *used_reg |= 1 << 2; + } else if (riscv_insn_is_c_lq(insn) || riscv_insn_is_c_lw(insn) || + riscv_insn_is_c_ld(insn)) { + *used_reg |= 1 << rvc_l_rs(insn); + } else if (riscv_insn_is_c_lqsp(insn) || riscv_insn_is_c_lwsp(insn) || + riscv_insn_is_c_ldsp(insn)) { + *used_reg |= 1 << 2; + } + /* li and lui does not have source reg */ + return; +is_rvi: +#endif + if (riscv_insn_is_arith_ri(insn) || riscv_insn_is_load(insn)) { + *used_reg |= 1 << rvi_rs1(insn); + } else if (riscv_insn_is_arith_rr(insn) || riscv_insn_is_store(insn) || + riscv_insn_is_amo(insn)) { + *used_reg |= 1 << rvi_rs1(insn); + *used_reg |= 1 << rvi_rs2(insn); + } else if (riscv_insn_is_branch(insn)) { + *used_reg |= 1 << rvi_rs1(insn); + *used_reg |= 1 << rvi_rs2(insn); + } else if (riscv_insn_is_jalr(insn)) { + *used_reg |= 1 << rvi_rs1(insn); + } +} + +static bool scan_code(unsigned long *addr, unsigned long paddr, + struct optimized_kprobe *op, uint32_t *used_reg) +{ + if (insn_jump_into_range(*addr, paddr + RVC_INSN_LEN, + paddr + op->optinsn.length)) + return false; + if (search_exception_tables(*addr)) + return false; + update_free_reg(*addr, used_reg); + *addr += GET_INSN_LENGTH(*(kprobe_opcode_t *)addr); + return true; +} + /* * The kprobe can be optimized when no in-function jump reaches to the * instructions replaced by optimized jump instructions(AUIPC/JALR). */ -static bool can_optimize(unsigned long paddr, struct optimized_kprobe *op) +static bool can_optimize(unsigned long paddr, struct optimized_kprobe *op, uint32_t *used_reg) { int ret; unsigned long addr, size = 0, offset = 0; struct kprobe *kp = get_kprobe((kprobe_opcode_t *)paddr); + /* + * All callee + */ + *used_reg = NON_CALLER_SAVED_MASK; + /* * Skip optimization if kprobe has been disarmed or instrumented * instruction support XOI. @@ -429,18 +513,14 @@ static bool can_optimize(unsigned long paddr, struct optimized_kprobe *op) */ addr = paddr - offset; while (addr < paddr) { - if (insn_jump_into_range(addr, paddr + RVC_INSN_LEN, - paddr + op->optinsn.length)) + if (!scan_code(&addr, paddr, op, used_reg)) return false; - addr += GET_INSN_LENGTH(*(kprobe_opcode_t *)addr); } - - addr = paddr + op->optinsn.length; + update_free_reg((unsigned long)&kp->opcode, used_reg); + addr = paddr + GET_INSN_LENGTH(*(kprobe_opcode_t *)&kp->opcode); while (addr < paddr - offset + size) { - if (insn_jump_into_range(addr, paddr + RVC_INSN_LEN, - paddr + op->optinsn.length)) + if (!scan_code(&addr, paddr, op, used_reg)) return false; - addr += GET_INSN_LENGTH(*(kprobe_opcode_t *)addr); } return true; @@ -469,10 +549,13 @@ int arch_prepare_optimized_kprobe(struct optimized_kprobe *op, { long rel; int rd, ra, ret; + u32 used_reg; kprobe_opcode_t *code = NULL, *slot = NULL; - if (!can_optimize((unsigned long)orig->addr, op)) + if (!can_optimize((unsigned long)orig->addr, op, &used_reg)) { + op->optinsn.rd = -1; return -EILSEQ; + } code = kzalloc(MAX_OPTINSN_SIZE, GFP_KERNEL); slot = get_optinsn_slot(); @@ -497,11 +580,17 @@ int arch_prepare_optimized_kprobe(struct optimized_kprobe *op, } /* - * Search two free registers, rd is used as to form AUIPC/JALR jumping - * to detour buffer, ra is used as to form JR jumping back from detour - * buffer. + * Search two free registers if no unused ones, rd is used as to form + * AUIPC/JALR jumping to detour buffer, ra is used as to form JR jumping + * back from detour buffer. */ - find_free_registers(orig, op, &rd, &ra); + if (used_reg == ALL_REG_OCCUPIED) { + find_free_registers(orig, op, &rd, &ra); + } else { + rd = ffz(used_reg); + ra = rd; + } + if (rd == 0 || ra == 0) { ret = -EILSEQ; goto on_error; @@ -545,6 +634,8 @@ void arch_optimize_kprobes(struct list_head *oplist) list_for_each_entry_safe(op, tmp, oplist, list) { WARN_ON(kprobe_disabled(&op->kp)); + if (op->optinsn.rd < 0) + continue; /* 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)),