From: Peter Zijlstra <peterz@infradead.org> To: x86@kernel.org Cc: peterz@infradead.org, linux-kernel@vger.kernel.org, rostedt@goodmis.org, mhiramat@kernel.org, bristot@redhat.com, jbaron@akamai.com, torvalds@linux-foundation.org, tglx@linutronix.de, mingo@kernel.org, namit@vmware.com, hpa@zytor.com, luto@kernel.org, ard.biesheuvel@linaro.org, jpoimboe@redhat.com, jeyu@kernel.org Subject: [PATCH v4 04/16] x86/alternatives: Add and use text_gen_insn() helper Date: Fri, 18 Oct 2019 09:35:29 +0200 [thread overview] Message-ID: <20191018074634.170477322@infradead.org> (raw) In-Reply-To: <20191018073525.768931536@infradead.org> Provide a simple helper function to create common instruction encodings. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Daniel Bristot de Oliveira <bristot@redhat.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> --- arch/x86/include/asm/text-patching.h | 2 + arch/x86/kernel/alternative.c | 36 +++++++++++++++++++++++++++++++++++ arch/x86/kernel/jump_label.c | 31 ++++++++++-------------------- arch/x86/kernel/kprobes/opt.c | 7 ------ 4 files changed, 50 insertions(+), 26 deletions(-) --- a/arch/x86/include/asm/text-patching.h +++ b/arch/x86/include/asm/text-patching.h @@ -49,6 +49,8 @@ extern void text_poke_bp(void *addr, con extern void text_poke_queue(void *addr, const void *opcode, size_t len, const void *emulate); extern void text_poke_finish(void); +extern void *text_gen_insn(u8 opcode, const void *addr, const void *dest); + extern int after_bootmem; extern __ro_after_init struct mm_struct *poking_mm; extern __ro_after_init unsigned long poking_addr; --- a/arch/x86/kernel/alternative.c +++ b/arch/x86/kernel/alternative.c @@ -1237,3 +1237,39 @@ void text_poke_bp(void *addr, const void text_poke_loc_init(&tp, addr, opcode, len, emulate); text_poke_bp_batch(&tp, 1); } + +union text_poke_insn { + u8 text[POKE_MAX_OPCODE_SIZE]; + struct { + u8 opcode; + s32 disp; + } __attribute__((packed)); +}; + +void *text_gen_insn(u8 opcode, const void *addr, const void *dest) +{ + static union text_poke_insn insn; /* text_mutex */ + int size = 0; + + lockdep_assert_held(&text_mutex); + + insn.opcode = opcode; + +#define __CASE(insn) \ + case insn##_INSN_OPCODE: size = insn##_INSN_SIZE; break + + switch(opcode) { + __CASE(INT3); + __CASE(CALL); + __CASE(JMP32); + __CASE(JMP8); + } + + if (size > 1) { + insn.disp = (long)dest - (long)(addr + size); + if (size == 2) + BUG_ON((insn.disp >> 31) != (insn.disp >> 7)); + } + + return &insn.text; +} --- a/arch/x86/kernel/jump_label.c +++ b/arch/x86/kernel/jump_label.c @@ -16,15 +16,7 @@ #include <asm/alternative.h> #include <asm/text-patching.h> -union jump_code_union { - char code[JUMP_LABEL_NOP_SIZE]; - struct { - char jump; - int offset; - } __attribute__((packed)); -}; - -static void bug_at(unsigned char *ip, int line) +static void bug_at(const void *ip, int line) { /* * The location is not an op that we were expecting. @@ -38,33 +30,32 @@ static void bug_at(unsigned char *ip, in static const void * __jump_label_set_jump_code(struct jump_entry *entry, enum jump_label_type type, int init) { - static union jump_code_union code; /* relies on text_mutex */ const unsigned char default_nop[] = { STATIC_KEY_INIT_NOP }; const unsigned char *ideal_nop = ideal_nops[NOP_ATOMIC5]; - const void *expect; + const void *expect, *code; + const void *addr, *dest; int line; - lockdep_assert_held(&text_mutex); + addr = (void *)jump_entry_code(entry); + dest = (void *)jump_entry_target(entry); - code.jump = JMP32_INSN_OPCODE; - code.offset = jump_entry_target(entry) - - (jump_entry_code(entry) + JUMP_LABEL_NOP_SIZE); + code = text_gen_insn(JMP32_INSN_OPCODE, addr, dest); if (init) { expect = default_nop; line = __LINE__; } else if (type == JUMP_LABEL_JMP) { expect = ideal_nop; line = __LINE__; } else { - expect = code.code; line = __LINE__; + expect = code; line = __LINE__; } - if (memcmp((void *)jump_entry_code(entry), expect, JUMP_LABEL_NOP_SIZE)) - bug_at((void *)jump_entry_code(entry), line); + if (memcmp(addr, expect, JUMP_LABEL_NOP_SIZE)) + bug_at(addr, line); if (type == JUMP_LABEL_NOP) - memcpy(&code, ideal_nop, JUMP_LABEL_NOP_SIZE); + code = ideal_nop; - return &code; + return code; } static void inline __jump_label_transform(struct jump_entry *entry, --- a/arch/x86/kernel/kprobes/opt.c +++ b/arch/x86/kernel/kprobes/opt.c @@ -447,18 +447,13 @@ void arch_optimize_kprobes(struct list_h void arch_unoptimize_kprobe(struct optimized_kprobe *op) { u8 insn_buff[RELATIVEJUMP_SIZE]; - u8 emulate_buff[RELATIVEJUMP_SIZE]; /* Set int3 to first byte for kprobes */ insn_buff[0] = BREAKPOINT_INSTRUCTION; memcpy(insn_buff + 1, op->optinsn.copied_insn, RELATIVE_ADDR_SIZE); - emulate_buff[0] = RELATIVEJUMP_OPCODE; - *(s32 *)(&emulate_buff[1]) = (s32)((long)op->optinsn.insn - - ((long)op->kp.addr + RELATIVEJUMP_SIZE)); - text_poke_bp(op->kp.addr, insn_buff, RELATIVEJUMP_SIZE, - emulate_buff); + text_gen_insn(JMP32_INSN_OPCODE, op->kp.addr, op->optinsn.insn)); } /*
next prev parent reply other threads:[~2019-10-18 7:53 UTC|newest] Thread overview: 70+ messages / expand[flat|nested] mbox.gz Atom feed top 2019-10-18 7:35 [PATCH v4 00/16] Rewrite x86/ftrace to use text_poke (and more) Peter Zijlstra 2019-10-18 7:35 ` [PATCH v4 01/16] x86/alternatives: Teach text_poke_bp() to emulate instructions Peter Zijlstra 2019-10-18 7:35 ` [PATCH v4 02/16] x86/alternatives: Update int3_emulate_push() comment Peter Zijlstra 2019-10-18 7:35 ` [PATCH v4 03/16] x86/alternatives,jump_label: Provide better text_poke() batching interface Peter Zijlstra 2019-10-21 8:48 ` Ingo Molnar 2019-10-21 9:21 ` Peter Zijlstra 2019-10-18 7:35 ` Peter Zijlstra [this message] 2019-10-18 7:35 ` [PATCH v4 05/16] x86/ftrace: Use text_poke() Peter Zijlstra 2019-10-18 7:35 ` [PATCH v4 06/16] x86/mm: Remove set_kernel_text_r[ow]() Peter Zijlstra 2019-10-18 7:35 ` [PATCH v4 07/16] x86/alternative: Add text_opcode_size() Peter Zijlstra 2019-10-18 7:35 ` [PATCH v4 08/16] x86/ftrace: Use text_gen_insn() Peter Zijlstra 2019-10-18 7:35 ` [PATCH v4 09/16] x86/alternative: Remove text_poke_loc::len Peter Zijlstra 2019-10-21 8:58 ` Ingo Molnar 2019-10-21 9:02 ` Ingo Molnar 2019-10-18 7:35 ` [PATCH v4 10/16] x86/alternative: Shrink text_poke_loc Peter Zijlstra 2019-10-21 9:01 ` Ingo Molnar 2019-10-21 9:25 ` Peter Zijlstra 2019-10-21 9:33 ` Ingo Molnar 2019-10-18 7:35 ` [PATCH v4 11/16] x86/kprobes: Convert to text-patching.h Peter Zijlstra 2019-10-21 14:57 ` Masami Hiramatsu 2019-10-18 7:35 ` [PATCH v4 12/16] x86/kprobes: Fix ordering Peter Zijlstra 2019-10-22 1:35 ` Masami Hiramatsu 2019-10-22 10:31 ` Peter Zijlstra 2019-10-18 7:35 ` [PATCH v4 13/16] arm/ftrace: Use __patch_text_real() Peter Zijlstra 2019-10-28 16:25 ` Will Deacon 2019-10-28 16:34 ` Peter Zijlstra 2019-10-28 16:35 ` Peter Zijlstra 2019-10-28 16:47 ` Will Deacon 2019-10-28 16:55 ` Peter Zijlstra 2019-10-18 7:35 ` [PATCH v4 14/16] module: Remove set_all_modules_text_*() Peter Zijlstra 2019-10-18 7:35 ` [PATCH v4 15/16] module: Move where we mark modules RO,X Peter Zijlstra 2019-10-21 13:53 ` Josh Poimboeuf 2019-10-21 14:14 ` Peter Zijlstra 2019-10-21 15:34 ` Peter Zijlstra 2019-10-21 15:44 ` Peter Zijlstra 2019-10-21 16:11 ` Peter Zijlstra 2019-10-22 11:31 ` Heiko Carstens 2019-10-22 12:31 ` Peter Zijlstra 2019-10-23 11:48 ` Peter Zijlstra 2019-10-23 15:16 ` Peter Zijlstra 2019-10-23 17:15 ` Josh Poimboeuf 2019-10-24 10:59 ` Peter Zijlstra 2019-10-24 18:31 ` Josh Poimboeuf 2019-10-24 20:33 ` Peter Zijlstra 2019-10-23 17:00 ` Josh Poimboeuf 2019-10-24 13:16 ` Peter Zijlstra 2019-10-25 6:44 ` Petr Mladek 2019-10-25 8:43 ` Peter Zijlstra 2019-10-25 10:06 ` Peter Zijlstra 2019-10-25 13:50 ` Josh Poimboeuf 2019-10-26 1:17 ` Josh Poimboeuf 2019-10-28 10:07 ` Peter Zijlstra 2019-10-28 10:43 ` Peter Zijlstra 2019-10-25 9:16 ` Peter Zijlstra 2019-10-22 2:21 ` Steven Rostedt 2019-10-22 20:24 ` Peter Zijlstra 2019-10-22 20:40 ` Steven Rostedt 2019-10-23 9:07 ` Peter Zijlstra 2019-10-23 18:52 ` Steven Rostedt 2019-10-24 10:16 ` Peter Zijlstra 2019-10-24 10:18 ` Peter Zijlstra 2019-10-24 15:00 ` Steven Rostedt 2019-10-24 16:43 ` Peter Zijlstra 2019-10-24 18:17 ` Steven Rostedt 2019-10-24 20:24 ` Peter Zijlstra 2019-10-24 20:28 ` Steven Rostedt 2019-10-18 7:35 ` [PATCH v4 16/16] ftrace: Merge ftrace_module_{init,enable}() Peter Zijlstra 2019-10-18 8:20 ` Peter Zijlstra 2019-10-21 9:09 ` [PATCH v4 00/16] Rewrite x86/ftrace to use text_poke (and more) Ingo Molnar 2019-10-21 13:38 ` Steven Rostedt
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