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(unknown [219.141.235.82]) by APP-05 (Coremail) with SMTP id zQCowACnrKByhmdj7bRnCA--.7053S5; Sun, 06 Nov 2022 18:03:34 +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 1/8] riscv/kprobe: Prepare the skeleton to implement RISCV OPTPROBES feature Date: Sun, 6 Nov 2022 18:03:09 +0800 Message-Id: <20221106100316.2803176-2-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--.7053S5 X-Coremail-Antispam: 1UD129KBjvJXoW3XF1fuF1xtFWfZw1ktw17GFg_yoW7KFWUpF s5Cwn5WrWkA3s3G3y3Jw1kuFWFqan5Wa17KryDZry5Xw45tr45Awn2grW5XryxGrs0gryf uF1Fvry5Cry3X3DanT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUPE14x267AKxVW5JVWrJwAFc2x0x2IEx4CE42xK8VAvwI8IcIk0 rVWrJVCq3wAFIxvE14AKwVWUJVWUGwA2048vs2IY020E87I2jVAFwI0_Jr4l82xGYIkIc2 x26xkF7I0E14v26r1I6r4UM28lY4IEw2IIxxk0rwA2F7IY1VAKz4vEj48ve4kI8wA2z4x0 Y4vE2Ix0cI8IcVAFwI0_Xr0_Ar1l84ACjcxK6xIIjxv20xvEc7CjxVAFwI0_Gr0_Cr1l84 ACjcxK6I8E87Iv67AKxVW0oVCq3wA2z4x0Y4vEx4A2jsIEc7CjxVAFwI0_GcCE3s1lnxkE FVAIw20F6cxK64vIFxWle2I262IYc4CY6c8Ij28IcVAaY2xG8wAqx4xG64xvF2IEw4CE5I 8CrVC2j2WlYx0E2Ix0cI8IcVAFwI0_Jr0_Jr4lYx0Ex4A2jsIE14v26r1j6r4UMcvjeVCF s4IE7xkEbVWUJVW8JwACjcxG0xvY0x0EwIxGrwACjI8F5VA0II8E6IAqYI8I648v4I1lFI xGxcIEc7CjxVA2Y2ka0xkIwI1l42xK82IYc2Ij64vIr41l4I8I3I0E4IkC6x0Yz7v_Jr0_ Gr1lx2IqxVAqx4xG67AKxVWUJVWUGwC20s026x8GjcxK67AKxVWUGVWUWwC2zVAF1VAY17 CE14v26r1q6r43MIIYrxkI7VAKI48JMIIF0xvE2Ix0cI8IcVAFwI0_Jr0_JF4lIxAIcVC0 I7IYx2IY6xkF7I0E14v26r4j6F4UMIIF0xvE42xK8VAvwI8IcIk0rVWUJVWUCwCI42IY6I 8E87Iv67AKxVWUJVW8JwCI42IY6I8E87Iv6xkF7I0E14v26r4j6r4UJbIYCTnIWIevJa73 UjIFyTuYvjfU5UUUUUUUU X-Originating-IP: [219.141.235.82] X-CM-SenderInfo: xfkh0w5xrntxyrx6ztxlovh3xfdvhtffof0/1tbiBwQCE2NnTgRK2QAAsP X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20221106_020351_698999_164EDF92 X-CRM114-Status: GOOD ( 16.28 ) 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 From: Liao Chang From: Liao Chang Prepare skeleton to implement optimized kprobe on RISCV, it is consist of Makfile, Kconfig and some architecture specific files: kprobe.h and opt.c opt.c include some macro, type definition and functions required by kprobe framework, opt_trampoline.S provide a piece of assembly code template used to construct the detour buffer as the target of long jump instruction(s) for each optimzed kprobe. Since the jump range of PC-relative instruction JAL is +/-2M, that is too small to reach the detour buffer, hence the foudamental idea to address OPTPROBES on RISCV is replace 'EBREAK' with 'AUIPC/JALR'. which means it needs to clobber one more instruction beside the kprobe instruction, furthermore, RISCV supports hybird RVI and RVC in single kernel binary, so in theory a pair of 'AUIPC/JALR' is about to clobber 10 bytes(3 RVC and 1 RVI, 2 bytes is padding for alignment) at worst case. The second hardsome problem is looking for one integer register as the destination of 'AUIPC/JALR' without any side-effect. Signed-off-by: Liao Chang Co-developed-by: Chen Guokai Signed-off-by: Chen Guokai --- arch/riscv/Kconfig | 1 + arch/riscv/include/asm/kprobes.h | 32 ++++++++++++++ arch/riscv/kernel/probes/Makefile | 1 + arch/riscv/kernel/probes/opt.c | 51 +++++++++++++++++++++++ arch/riscv/kernel/probes/opt_trampoline.S | 12 ++++++ 5 files changed, 97 insertions(+) create mode 100644 arch/riscv/kernel/probes/opt.c create mode 100644 arch/riscv/kernel/probes/opt_trampoline.S diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig index 6b48a3ae9843..ca29306c93e2 100644 --- a/arch/riscv/Kconfig +++ b/arch/riscv/Kconfig @@ -99,6 +99,7 @@ config RISCV select HAVE_KPROBES if !XIP_KERNEL select HAVE_KPROBES_ON_FTRACE if !XIP_KERNEL select HAVE_KRETPROBES if !XIP_KERNEL + select HAVE_OPTPROBES if !XIP_KERNEL select HAVE_MOVE_PMD select HAVE_MOVE_PUD select HAVE_PCI diff --git a/arch/riscv/include/asm/kprobes.h b/arch/riscv/include/asm/kprobes.h index 217ef89f22b9..22b73a2fd1fd 100644 --- a/arch/riscv/include/asm/kprobes.h +++ b/arch/riscv/include/asm/kprobes.h @@ -43,5 +43,37 @@ bool kprobe_single_step_handler(struct pt_regs *regs); void __kretprobe_trampoline(void); void __kprobes *trampoline_probe_handler(struct pt_regs *regs); +#ifdef CONFIG_OPTPROBES + +/* optinsn template addresses */ +extern __visible kprobe_opcode_t optprobe_template_entry[]; +extern __visible kprobe_opcode_t optprobe_template_end[]; + +#define MAX_OPTINSN_SIZE \ + ((unsigned long)optprobe_template_end - \ + (unsigned long)optprobe_template_entry) + +/* + * For RVI and RVC hybird encoding kernel, althought long jump just needs + * 2 RVI instructions(AUIPC+JALR), optimized instructions is 10 bytes long + * at most to ensure no RVI would be truncated actually, so it means four + * combinations: + * - 2 RVI + * - 4 RVC + * - 2 RVC + 1 RVI + * - 3 RVC + 1 RVI (truncated, need padding) + */ +#define MAX_COPIED_INSN 4 +#define MAX_OPTIMIZED_LENGTH 10 + +struct arch_optimized_insn { + kprobe_opcode_t copied_insn[MAX_COPIED_INSN]; + /* detour code buffer */ + kprobe_opcode_t *insn; + unsigned long length; + int rd; +}; + +#endif /* CONFIG_OPTPROBES */ #endif /* CONFIG_KPROBES */ #endif /* _ASM_RISCV_KPROBES_H */ diff --git a/arch/riscv/kernel/probes/Makefile b/arch/riscv/kernel/probes/Makefile index 7f0840dcc31b..6255b4600875 100644 --- a/arch/riscv/kernel/probes/Makefile +++ b/arch/riscv/kernel/probes/Makefile @@ -3,4 +3,5 @@ obj-$(CONFIG_KPROBES) += kprobes.o decode-insn.o simulate-insn.o obj-$(CONFIG_KPROBES) += kprobes_trampoline.o obj-$(CONFIG_KPROBES_ON_FTRACE) += ftrace.o obj-$(CONFIG_UPROBES) += uprobes.o decode-insn.o simulate-insn.o +obj-$(CONFIG_OPTPROBES) += opt.o opt_trampoline.o CFLAGS_REMOVE_simulate-insn.o = $(CC_FLAGS_FTRACE) diff --git a/arch/riscv/kernel/probes/opt.c b/arch/riscv/kernel/probes/opt.c new file mode 100644 index 000000000000..56c8a227c857 --- /dev/null +++ b/arch/riscv/kernel/probes/opt.c @@ -0,0 +1,51 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Kernel Probes Jump Optimization (Optprobes) + * + * Copyright (C) Guokai Chen, 2022 + * Author: Guokai Chen chenguokai17@mails.ucas.ac.cn + */ + +#define pr_fmt(fmt) "optprobe: " fmt + +#include +#include + +int arch_prepared_optinsn(struct arch_optimized_insn *optinsn) +{ + return 0; +} + +int arch_check_optimized_kprobe(struct optimized_kprobe *op) +{ + return 0; +} + +int arch_prepare_optimized_kprobe(struct optimized_kprobe *op, + struct kprobe *orig) +{ + return 0; +} + +void arch_remove_optimized_kprobe(struct optimized_kprobe *op) +{ +} + +void arch_optimize_kprobes(struct list_head *oplist) +{ +} + +void arch_unoptimize_kprobes(struct list_head *oplist, + struct list_head *done_list) +{ +} + +void arch_unoptimize_kprobe(struct optimized_kprobe *op) +{ +} + +int arch_within_optimized_kprobe(struct optimized_kprobe *op, + kprobe_opcode_t *addr) +{ + return 0; +} diff --git a/arch/riscv/kernel/probes/opt_trampoline.S b/arch/riscv/kernel/probes/opt_trampoline.S new file mode 100644 index 000000000000..16160c4367ff --- /dev/null +++ b/arch/riscv/kernel/probes/opt_trampoline.S @@ -0,0 +1,12 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Copyright (C) 2022 Guokai Chen + */ + +#include + +#incldue +#include + +SYM_ENTRY(optprobe_template_entry, SYM_L_GLOBAL, SYM_A_NONE) +SYM_ENTRY(optprobe_template_end, SYM_L_GLOBAL, SYM_A_NONE)