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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 08/16] x86/ftrace: Use text_gen_insn()
Date: Fri, 18 Oct 2019 09:35:33 +0200	[thread overview]
Message-ID: <20191018074634.400398363@infradead.org> (raw)
In-Reply-To: <20191018073525.768931536@infradead.org>

Replace the ftrace_code_union with the generic text_gen_insn() helper,
which does exactly this.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
 arch/x86/include/asm/text-patching.h |   25 ++++++++++++++++++++++++-
 arch/x86/kernel/alternative.c        |   26 --------------------------
 arch/x86/kernel/ftrace.c             |   32 +++++++-------------------------
 3 files changed, 31 insertions(+), 52 deletions(-)

--- a/arch/x86/include/asm/text-patching.h
+++ b/arch/x86/include/asm/text-patching.h
@@ -80,7 +80,30 @@ static inline int text_opcode_size(u8 op
 	return size;
 }
 
-extern void *text_gen_insn(u8 opcode, const void *addr, const void *dest);
+union text_poke_insn {
+	u8 text[POKE_MAX_OPCODE_SIZE];
+	struct {
+		u8 opcode;
+		s32 disp;
+	} __attribute__((packed));
+};
+
+static __always_inline
+void *text_gen_insn(u8 opcode, const void *addr, const void *dest)
+{
+	static union text_poke_insn insn; /* per instance */
+	int size = text_opcode_size(opcode);
+
+	insn.opcode = opcode;
+
+	if (size > 1) {
+		insn.disp = (long)dest - (long)(addr + size);
+		if (size == 2)
+			BUG_ON((insn.disp >> 31) != (insn.disp >> 7));
+	}
+
+	return &insn.text;
+}
 
 extern int after_bootmem;
 extern __ro_after_init struct mm_struct *poking_mm;
--- a/arch/x86/kernel/alternative.c
+++ b/arch/x86/kernel/alternative.c
@@ -1247,29 +1247,3 @@ void __ref text_poke_bp(void *addr, cons
 	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 = text_opcode_size(opcode);
-
-	lockdep_assert_held(&text_mutex);
-
-	insn.opcode = opcode;
-
-	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/ftrace.c
+++ b/arch/x86/kernel/ftrace.c
@@ -58,24 +58,6 @@ int ftrace_arch_code_modify_post_process
 	return 0;
 }
 
-union ftrace_code_union {
-	char code[MCOUNT_INSN_SIZE];
-	struct {
-		char op;
-		int offset;
-	} __attribute__((packed));
-};
-
-static const char *ftrace_text_replace(char op, unsigned long ip, unsigned long addr)
-{
-	static union ftrace_code_union calc;
-
-	calc.op = op;
-	calc.offset = (int)(addr - (ip + MCOUNT_INSN_SIZE));
-
-	return calc.code;
-}
-
 static const char *ftrace_nop_replace(void)
 {
 	return ideal_nops[NOP_ATOMIC5];
@@ -83,7 +65,7 @@ static const char *ftrace_nop_replace(vo
 
 static const char *ftrace_call_replace(unsigned long ip, unsigned long addr)
 {
-	return ftrace_text_replace(CALL_INSN_OPCODE, ip, addr);
+	return text_gen_insn(CALL_INSN_OPCODE, (void *)ip, (void *)addr);
 }
 
 static int ftrace_verify_code(unsigned long ip, const char *old_code)
@@ -475,20 +457,20 @@ void arch_ftrace_update_trampoline(struc
 /* Return the address of the function the trampoline calls */
 static void *addr_from_call(void *ptr)
 {
-	union ftrace_code_union calc;
+	union text_poke_insn call;
 	int ret;
 
-	ret = probe_kernel_read(&calc, ptr, MCOUNT_INSN_SIZE);
+	ret = probe_kernel_read(&call, ptr, CALL_INSN_SIZE);
 	if (WARN_ON_ONCE(ret < 0))
 		return NULL;
 
 	/* Make sure this is a call */
-	if (WARN_ON_ONCE(calc.op != 0xe8)) {
-		pr_warn("Expected e8, got %x\n", calc.op);
+	if (WARN_ON_ONCE(call.opcode != CALL_INSN_OPCODE)) {
+		pr_warn("Expected E8, got %x\n", call.opcode);
 		return NULL;
 	}
 
-	return ptr + MCOUNT_INSN_SIZE + calc.offset;
+	return ptr + CALL_INSN_SIZE + call.disp;
 }
 
 void prepare_ftrace_return(unsigned long self_addr, unsigned long *parent,
@@ -557,7 +539,7 @@ extern void ftrace_graph_call(void);
 
 static const char *ftrace_jmp_replace(unsigned long ip, unsigned long addr)
 {
-	return ftrace_text_replace(JMP32_INSN_OPCODE, ip, addr);
+	return text_gen_insn(JMP32_INSN_OPCODE, (void *)ip, (void *)addr);
 }
 
 static int ftrace_mod_jmp(unsigned long ip, void *func)



  parent reply	other threads:[~2019-10-18  7:51 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 ` [PATCH v4 04/16] x86/alternatives: Add and use text_gen_insn() helper Peter Zijlstra
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 ` Peter Zijlstra [this message]
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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