From nobody Mon Apr 13 20:07:34 2026 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D5464C4332F for ; Wed, 16 Nov 2022 08:08:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238561AbiKPIIP (ORCPT ); Wed, 16 Nov 2022 03:08:15 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41228 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233161AbiKPIHm (ORCPT ); Wed, 16 Nov 2022 03:07:42 -0500 Received: from loongson.cn (mail.loongson.cn [114.242.206.163]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 22E2AC75D for ; Wed, 16 Nov 2022 00:07:34 -0800 (PST) Received: from loongson.cn (unknown [113.200.148.30]) by gateway (Coremail) with SMTP id _____8AxHLZFmnRjPbIHAA--.10526S3; Wed, 16 Nov 2022 16:07:33 +0800 (CST) Received: from localhost.localdomain (unknown [113.200.148.30]) by localhost.localdomain (Coremail) with SMTP id AQAAf8Dx9VY6mnRjQ54UAA--.36317S10; Wed, 16 Nov 2022 16:07:33 +0800 (CST) From: Qing Zhang To: Huacai Chen , Steven Rostedt , Ingo Molnar Cc: loongarch@lists.linux.dev, linux-kernel@vger.kernel.org Subject: [PATCH v8 8/9] LoongArch: modules/ftrace: Initialize PLT at load time Date: Wed, 16 Nov 2022 16:07:21 +0800 Message-Id: <20221116080722.4745-9-zhangqing@loongson.cn> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20221116080722.4745-1-zhangqing@loongson.cn> References: <20221116080722.4745-1-zhangqing@loongson.cn> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-CM-TRANSID: AQAAf8Dx9VY6mnRjQ54UAA--.36317S10 X-CM-SenderInfo: x2kd0wptlqwqxorr0wxvrqhubq/ X-Coremail-Antispam: 1Uk129KBjvJXoWfGF47Jr13WF1UJFW8ZF17GFg_yoWDKF1rpF yqywn5GrWUGFn3Wa4v9wn8ur15GFZ7W342gFW3G34akw42qry5AF10kr90yFyjqws8uFWS ga1fur4j9FW7Xw7anT9S1TB71UUUUjUqnTZGkaVYY2UrUUUUj1kv1TuYvTs0mT0YCTnIWj qI5I8CrVACY4xI64kE6c02F40Ex7xfYxn0WfASr-VFAUDa7-sFnT9fnUUIcSsGvfJTRUUU bakYFVCjjxCrM7AC8VAFwI0_Jr0_Gr1l1xkIjI8I6I8E6xAIw20EY4v20xvaj40_Wr0E3s 1l1IIY67AEw4v_Jrv_JF1l8cAvFVAK0II2c7xJM28CjxkF64kEwVA0rcxSw2x7M28EF7xv wVC0I7IYx2IY67AKxVW7JVWDJwA2z4x0Y4vE2Ix0cI8IcVCY1x0267AKxVWxJVW8Jr1l84 ACjcxK6I8E87Iv67AKxVW8Jr0_Cr1UM28EF7xvwVC2z280aVCY1x0267AKxVWxJr0_GcWl n4kS14v26r1Y6r17M2AIxVAIcxkEcVAq07x20xvEncxIr21l57IF6xkI12xvs2x26I8E6x ACxx1l5I8CrVACY4xI64kE6c02F40Ex7xfMcIj6xIIjxv20xvE14v26rWY6Fy7McIj6I8E 87Iv67AKxVW8Jr0_Cr1UMcvjeVCFs4IE7xkEbVWUJVW8JwACjcxG0xvY0x0EwIxGrwCF04 k20xvY0x0EwIxGrwCFx2IqxVCFs4IE7xkEbVWUJVW8JwCFI7km07C267AKxVWUXVWUAwC2 0s026c02F40E14v26r1j6r18MI8I3I0E7480Y4vE14v26r106r1rMI8E67AF67kF1VAFwI 0_JF0_Jw1lIxkGc2Ij64vIr41lIxAIcVC0I7IYx2IY67AKxVW7JVWDJwCI42IY6xIIjxv2 0xvEc7CjxVAFwI0_Gr0_Cr1lIxAIcVCF04k26cxKx2IYs7xG6r1j6r1xMIIF0xvEx4A2js IE14v26F4j6r4UJwCI42IY6I8E87Iv6xkF7I0E14v26r4j6r4UJbIYCTnIWIevJa73UjIF yTuYvjxUs038UUUUU Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" To Implement ftrace trampiones through plt entry. Tested by forcing ftrace_make_call() to use the module PLT, and then loading up a module after setting up ftrace with: | echo ":mod:" > set_ftrace_filter; | echo function > current_tracer; | modprobe Since FTRACE_ADDR/FTRACE_REGS_ADDR is only defined when CONFIG_DYNAMIC_FTRA= CE is selected, we wrap its use along with most of module_init_ftrace_plt() wi= th ifdeffery rather than using IS_ENABLED(). Signed-off-by: Qing Zhang --- arch/loongarch/include/asm/ftrace.h | 4 ++ arch/loongarch/include/asm/inst.h | 3 + arch/loongarch/include/asm/module.h | 5 +- arch/loongarch/include/asm/module.lds.h | 1 + arch/loongarch/kernel/ftrace_dyn.c | 79 +++++++++++++++++++++++++ arch/loongarch/kernel/inst.c | 11 ++++ arch/loongarch/kernel/module-sections.c | 11 ++++ arch/loongarch/kernel/module.c | 22 +++++++ 8 files changed, 135 insertions(+), 1 deletion(-) diff --git a/arch/loongarch/include/asm/ftrace.h b/arch/loongarch/include/a= sm/ftrace.h index 6c6187a01c68..e8b58d8f99ec 100644 --- a/arch/loongarch/include/asm/ftrace.h +++ b/arch/loongarch/include/asm/ftrace.h @@ -8,6 +8,10 @@ =20 #define GRAPH_FAKE_OFFSET (sizeof(struct pt_regs) - offsetof(struct pt_reg= s, regs[1])) =20 +#define FTRACE_PLT_IDX 0 +#define FTRACE_REGS_PLT_IDX 1 +#define NR_FTRACE_PLTS 2 + #ifdef CONFIG_FUNCTION_TRACER #define MCOUNT_INSN_SIZE 4 /* sizeof mcount call */ =20 diff --git a/arch/loongarch/include/asm/inst.h b/arch/loongarch/include/asm= /inst.h index 59fee75590e9..417d6b8bc43e 100644 --- a/arch/loongarch/include/asm/inst.h +++ b/arch/loongarch/include/asm/inst.h @@ -13,10 +13,12 @@ =20 #define ADDR_IMMMASK_LU52ID 0xFFF0000000000000 #define ADDR_IMMMASK_LU32ID 0x000FFFFF00000000 +#define ADDR_IMMMASK_LU12IW 0x00000000FFFFF000 #define ADDR_IMMMASK_ADDU16ID 0x00000000FFFF0000 =20 #define ADDR_IMMSHIFT_LU52ID 52 #define ADDR_IMMSHIFT_LU32ID 32 +#define ADDR_IMMSHIFT_LU12IW 12 #define ADDR_IMMSHIFT_ADDU16ID 16 =20 #define ADDR_IMM(addr, INSN) ((addr & ADDR_IMMMASK_##INSN) >> ADDR_IMMSHIF= T_##INSN) @@ -361,6 +363,7 @@ u32 larch_insn_gen_or(enum loongarch_gpr rd, enum loong= arch_gpr rj, enum loongarch_gpr rk); u32 larch_insn_gen_move(enum loongarch_gpr rd, enum loongarch_gpr rj); =20 +u32 larch_insn_gen_lu12iw(enum loongarch_gpr rd, int imm); u32 larch_insn_gen_lu32id(enum loongarch_gpr rd, int imm); u32 larch_insn_gen_lu52id(enum loongarch_gpr rd, enum loongarch_gpr rj, in= t imm); u32 larch_insn_gen_jirl(enum loongarch_gpr rd, enum loongarch_gpr rj, unsi= gned long pc, unsigned long dest); diff --git a/arch/loongarch/include/asm/module.h b/arch/loongarch/include/a= sm/module.h index b29b19a46f42..a311cfec2b23 100644 --- a/arch/loongarch/include/asm/module.h +++ b/arch/loongarch/include/asm/module.h @@ -20,6 +20,9 @@ struct mod_arch_specific { struct mod_section got; struct mod_section plt; struct mod_section plt_idx; + + /* for CONFIG_DYNAMIC_FTRACE */ + struct plt_entry *ftrace_trampolines; }; =20 struct got_entry { @@ -49,7 +52,7 @@ static inline struct plt_entry emit_plt_entry(unsigned lo= ng val) { u32 lu12iw, lu32id, lu52id, jirl; =20 - lu12iw =3D (lu12iw_op << 25 | (((val >> 12) & 0xfffff) << 5) | LOONGARCH_= GPR_T1); + lu12iw =3D larch_insn_gen_lu12iw(LOONGARCH_GPR_T1, ADDR_IMM(val, LU12IW)); lu32id =3D larch_insn_gen_lu32id(LOONGARCH_GPR_T1, ADDR_IMM(val, LU32ID)); lu52id =3D larch_insn_gen_lu52id(LOONGARCH_GPR_T1, LOONGARCH_GPR_T1, ADDR= _IMM(val, LU52ID)); jirl =3D larch_insn_gen_jirl(0, LOONGARCH_GPR_T1, 0, (val & 0xfff)); diff --git a/arch/loongarch/include/asm/module.lds.h b/arch/loongarch/inclu= de/asm/module.lds.h index a3d1bc0fcc72..438f09d4ccf4 100644 --- a/arch/loongarch/include/asm/module.lds.h +++ b/arch/loongarch/include/asm/module.lds.h @@ -5,4 +5,5 @@ SECTIONS { .got : { BYTE(0) } .plt : { BYTE(0) } .plt.idx : { BYTE(0) } + .ftrace_trampoline : { BYTE(0) } } diff --git a/arch/loongarch/kernel/ftrace_dyn.c b/arch/loongarch/kernel/ftr= ace_dyn.c index cd64887e26b5..b070ce225989 100644 --- a/arch/loongarch/kernel/ftrace_dyn.c +++ b/arch/loongarch/kernel/ftrace_dyn.c @@ -9,6 +9,7 @@ #include =20 #include +#include =20 static int ftrace_modify_code(unsigned long pc, u32 old, u32 new, bool validate) @@ -72,12 +73,63 @@ int ftrace_init_nop(struct module *mod, struct dyn_ftra= ce *rec) return ftrace_modify_code(pc, old, new, true); } =20 +static inline int __get_mod(struct module **mod, unsigned long addr) +{ + preempt_disable(); + *mod =3D __module_text_address(addr); + preempt_enable(); + + if (WARN_ON(!(*mod))) + return -EINVAL; + + return 0; +} + +static struct plt_entry *get_ftrace_plt(struct module *mod, unsigned long = addr) +{ + struct plt_entry *plt =3D mod->arch.ftrace_trampolines; + + if (addr =3D=3D FTRACE_ADDR) + return &plt[FTRACE_PLT_IDX]; + if (addr =3D=3D FTRACE_REGS_ADDR && + IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_REGS)) + return &plt[FTRACE_REGS_PLT_IDX]; + + return NULL; +} + +static unsigned long get_plt_addr(struct module *mod, unsigned long addr) +{ + struct plt_entry *plt; + + plt =3D get_ftrace_plt(mod, addr); + if (!plt) { + pr_err("ftrace: no module PLT for %ps\n", (void *)addr); + return -EINVAL; + } + + return (unsigned long)plt; +} + int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr) { unsigned long pc; + long offset; u32 old, new; =20 pc =3D rec->ip + LOONGARCH_INSN_SIZE; + offset =3D (long)pc - (long)addr; + + if (offset < -SZ_128M || offset >=3D SZ_128M) { + int ret; + struct module *mod; + + ret =3D __get_mod(&mod, pc); + if (ret) + return ret; + + addr =3D get_plt_addr(mod, addr); + } =20 old =3D larch_insn_gen_nop(); new =3D larch_insn_gen_bl(pc, addr); @@ -89,9 +141,22 @@ int ftrace_make_nop(struct module *mod, struct dyn_ftra= ce *rec, unsigned long addr) { unsigned long pc; + long offset; u32 old, new; =20 pc =3D rec->ip + LOONGARCH_INSN_SIZE; + offset =3D (long)pc - (long)addr; + + if (offset < -SZ_128M || offset >=3D SZ_128M) { + int ret; + struct module *mod; + + ret =3D __get_mod(&mod, pc); + if (ret) + return ret; + + addr =3D get_plt_addr(mod, addr); + } =20 new =3D larch_insn_gen_nop(); old =3D larch_insn_gen_bl(pc, addr); @@ -108,6 +173,20 @@ int ftrace_modify_call(struct dyn_ftrace *rec, unsigne= d long old_addr, u32 old, new; =20 pc =3D rec->ip + LOONGARCH_INSN_SIZE; + offset =3D (long)pc - (long)addr; + + if (offset < -SZ_128M || offset >=3D SZ_128M) { + int ret; + struct module *mod; + + ret =3D __get_mod(&mod, pc); + if (ret) + return ret; + + addr =3D get_plt_addr(mod, addr); + + old_addr =3D get_plt_addr(mod, old_addr); + } =20 old =3D larch_insn_gen_bl(pc, old_addr); new =3D larch_insn_gen_bl(pc, addr); diff --git a/arch/loongarch/kernel/inst.c b/arch/loongarch/kernel/inst.c index 2d2e942eb06a..0d6bd7000ba6 100644 --- a/arch/loongarch/kernel/inst.c +++ b/arch/loongarch/kernel/inst.c @@ -103,6 +103,17 @@ u32 larch_insn_gen_bl(unsigned long pc, unsigned long = dest) return insn.word; } =20 +u32 larch_insn_gen_lu12iw(enum loongarch_gpr rd, int imm) +{ + union loongarch_instruction insn; + + insn.reg1i20_format.opcode =3D lu12iw_op; + insn.reg1i20_format.rd =3D rd; + insn.reg1i20_format.immediate =3D imm; + + return insn.word; +} + u32 larch_insn_gen_lu32id(enum loongarch_gpr rd, int imm) { union loongarch_instruction insn; diff --git a/arch/loongarch/kernel/module-sections.c b/arch/loongarch/kerne= l/module-sections.c index d296a70b758f..bd1a96691c98 100644 --- a/arch/loongarch/kernel/module-sections.c +++ b/arch/loongarch/kernel/module-sections.c @@ -4,6 +4,7 @@ */ =20 #include +#include #include #include =20 @@ -103,6 +104,7 @@ int module_frob_arch_sections(Elf_Ehdr *ehdr, Elf_Shdr = *sechdrs, char *secstrings, struct module *mod) { unsigned int i, num_plts =3D 0, num_gots =3D 0; + Elf_Shdr *tramp =3D NULL; =20 /* * Find the empty .plt sections. @@ -114,6 +116,8 @@ int module_frob_arch_sections(Elf_Ehdr *ehdr, Elf_Shdr = *sechdrs, mod->arch.plt.shdr =3D sechdrs + i; else if (!strcmp(secstrings + sechdrs[i].sh_name, ".plt.idx")) mod->arch.plt_idx.shdr =3D sechdrs + i; + else if (!strcmp(secstrings + sechdrs[i].sh_name, ".ftrace_trampoline")) + tramp =3D sechdrs + i; } =20 if (!mod->arch.got.shdr) { @@ -166,5 +170,12 @@ int module_frob_arch_sections(Elf_Ehdr *ehdr, Elf_Shdr= *sechdrs, mod->arch.plt_idx.num_entries =3D 0; mod->arch.plt_idx.max_entries =3D num_plts; =20 + if (tramp) { + tramp->sh_type =3D SHT_NOBITS; + tramp->sh_flags =3D SHF_EXECINSTR | SHF_ALLOC; + tramp->sh_addralign =3D __alignof__(struct plt_entry); + tramp->sh_size =3D NR_FTRACE_PLTS * sizeof(struct plt_entry); + } + return 0; } diff --git a/arch/loongarch/kernel/module.c b/arch/loongarch/kernel/module.c index 825fcf77f9e7..8dc6ea0a981e 100644 --- a/arch/loongarch/kernel/module.c +++ b/arch/loongarch/kernel/module.c @@ -10,6 +10,7 @@ =20 #include #include +#include #include #include #include @@ -18,6 +19,7 @@ #include #include #include +#include =20 static int rela_stack_push(s64 stack_value, s64 *rela_stack, size_t *rela_= stack_top) { @@ -458,6 +460,24 @@ void *module_alloc(unsigned long size) GFP_KERNEL, PAGE_KERNEL, 0, NUMA_NO_NODE, __builtin_return_address(0)); } =20 +static int module_init_ftrace_plt(const Elf_Ehdr *hdr, const Elf_Shdr *sec= hdrs, + struct module *mod) +{ +#ifdef CONFIG_DYNAMIC_FTRACE + struct plt_entry *ftrace_plts; + + ftrace_plts =3D (void *)sechdrs->sh_addr; + + ftrace_plts[FTRACE_PLT_IDX] =3D emit_plt_entry(FTRACE_ADDR); + + if (IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_REGS)) + ftrace_plts[FTRACE_REGS_PLT_IDX] =3D emit_plt_entry(FTRACE_REGS_ADDR); + + mod->arch.ftrace_trampolines =3D ftrace_plts; +#endif + return 0; +} + int module_finalize(const Elf_Ehdr *hdr, const Elf_Shdr *sechdrs, struct module *mod) { @@ -467,6 +487,8 @@ int module_finalize(const Elf_Ehdr *hdr, for (s =3D sechdrs, se =3D sechdrs + hdr->e_shnum; s < se; s++) { if (!strcmp(".altinstructions", secstrs + s->sh_name)) apply_alternatives((void *)s->sh_addr, (void *)s->sh_addr + s->sh_size); + if (!strcmp(".ftrace_trampoline", secstrs + s->sh_name)) + module_init_ftrace_plt(hdr, s, mod); } =20 return 0; --=20 2.36.0