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
Subject: [PATCH v3 4/6] x86/alternatives: Add and use text_gen_insn() helper
Date: Mon, 07 Oct 2019 10:17:20 +0200 [thread overview]
Message-ID: <20191007081945.05309765.9@infradead.org> (raw)
In-Reply-To: 20191007081716.07616230.8@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:[~2019-10-07 11:24 UTC|newest]
Thread overview: 128+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-07 9:02 [RESEND] everything text-poke: ftrace, modules, static_call and jump_label Peter Zijlstra
2019-10-07 8:17 ` [PATCH v3 0/6] Rewrite x86/ftrace to use text_poke() Peter Zijlstra
2019-10-07 8:17 ` [PATCH v3 1/6] x86/alternatives: Teach text_poke_bp() to emulate instructions Peter Zijlstra
2019-10-08 14:29 ` Borislav Petkov
2019-10-08 14:40 ` Steven Rostedt
2019-10-08 14:50 ` Borislav Petkov
2019-10-08 14:48 ` Peter Zijlstra
2019-10-08 14:54 ` Borislav Petkov
2019-10-08 15:04 ` Steven Rostedt
2019-10-08 15:24 ` Borislav Petkov
2019-10-09 12:03 ` Daniel Bristot de Oliveira
2019-10-07 8:17 ` [PATCH v3 2/6] x86/alternatives: Update int3_emulate_push() comment Peter Zijlstra
2019-10-07 8:17 ` [PATCH v3 3/6] x86/alternatives,jump_label: Provide better text_poke() batching interface Peter Zijlstra
2019-10-09 12:04 ` Daniel Bristot de Oliveira
2019-10-07 8:17 ` Peter Zijlstra [this message]
2019-10-08 6:23 ` [PATCH v3 4/6] x86/alternatives: Add and use text_gen_insn() helper Masami Hiramatsu
2019-10-08 8:15 ` Peter Zijlstra
2019-10-07 8:17 ` [PATCH v3 5/6] x86/ftrace: Use text_poke() Peter Zijlstra
2019-10-08 14:43 ` Steven Rostedt
2019-10-08 17:11 ` Peter Zijlstra
2019-10-08 17:27 ` Steven Rostedt
2019-10-10 2:41 ` Steven Rostedt
2019-10-10 9:20 ` Peter Zijlstra
2019-10-10 13:19 ` Steven Rostedt
2019-10-10 14:05 ` Peter Zijlstra
2019-10-10 15:54 ` Steven Rostedt
2019-10-10 17:28 ` Peter Zijlstra
2019-10-10 17:48 ` Steven Rostedt
2019-10-11 10:45 ` Peter Zijlstra
2019-10-11 10:47 ` Peter Zijlstra
2019-10-11 10:50 ` Peter Zijlstra
2019-10-11 12:59 ` Peter Zijlstra
2019-10-11 13:33 ` Steven Rostedt
2019-10-11 13:45 ` Peter Zijlstra
2019-10-15 13:07 ` Jessica Yu
2019-10-15 13:56 ` Peter Zijlstra
2019-10-15 14:11 ` Peter Zijlstra
2019-10-15 14:13 ` Miroslav Benes
2019-10-15 15:06 ` Joe Lawrence
2019-10-15 15:31 ` Jessica Yu
2019-10-15 22:17 ` Joe Lawrence
2019-10-15 22:27 ` Steven Rostedt
2019-10-16 7:42 ` Peter Zijlstra
2019-10-16 10:15 ` Miroslav Benes
2019-10-21 15:05 ` Josh Poimboeuf
2020-01-20 16:50 ` Josh Poimboeuf
2020-01-21 8:35 ` Miroslav Benes
2020-01-21 16:10 ` Josh Poimboeuf
2020-01-22 10:09 ` Miroslav Benes
2020-01-22 21:42 ` Josh Poimboeuf
2020-01-28 9:28 ` Miroslav Benes
2020-01-28 15:00 ` Josh Poimboeuf
2020-01-28 15:40 ` Petr Mladek
2020-01-28 17:02 ` Josh Poimboeuf
2020-01-29 0:46 ` Jiri Kosina
2020-01-29 2:17 ` Josh Poimboeuf
2020-01-29 3:14 ` Jiri Kosina
2020-01-29 12:28 ` Miroslav Benes
2020-01-29 15:59 ` Josh Poimboeuf
2020-01-30 9:53 ` Petr Mladek
2020-01-30 14:17 ` Josh Poimboeuf
2020-01-31 7:17 ` Petr Mladek
2020-01-22 12:15 ` Miroslav Benes
2020-01-22 15:05 ` Miroslav Benes
2020-01-22 22:03 ` Josh Poimboeuf
2020-01-23 10:19 ` Martin Jambor
2019-10-16 7:49 ` Peter Zijlstra
2019-10-16 10:20 ` Miroslav Benes
2019-10-16 13:29 ` Miroslav Benes
2019-10-18 13:03 ` Jessica Yu
2019-10-18 13:40 ` Petr Mladek
2019-10-21 14:14 ` Jessica Yu
2019-10-21 15:31 ` Josh Poimboeuf
2019-10-22 8:27 ` Miroslav Benes
2019-10-22 14:31 ` Josh Poimboeuf
2019-10-23 9:04 ` Miroslav Benes
2019-10-16 6:51 ` Miroslav Benes
2019-10-16 9:23 ` Peter Zijlstra
2019-10-16 9:36 ` Jessica Yu
2019-10-16 9:51 ` Peter Zijlstra
2019-10-16 12:39 ` Peter Zijlstra
2019-10-22 8:45 ` Miroslav Benes
2019-10-15 14:42 ` Peter Zijlstra
2019-10-15 18:31 ` Peter Zijlstra
2019-10-15 15:51 ` Jessica Yu
2019-10-15 13:28 ` Steven Rostedt
2019-10-15 13:42 ` Peter Zijlstra
2019-10-15 16:09 ` Jessica Yu
2019-10-07 8:17 ` [PATCH v3 6/6] x86/mm: Remove set_kernel_text_r[ow]() Peter Zijlstra
2019-10-08 15:07 ` [PATCH v3 0/6] Rewrite x86/ftrace to use text_poke() Steven Rostedt
2019-10-07 8:25 ` [PATCH v2 0/4] Propagate module notifier errors Peter Zijlstra
2019-10-07 8:25 ` [PATCH v2 1/4] notifier: Fix broken error handling pattern Peter Zijlstra
2019-10-10 22:01 ` Rafael J. Wysocki
2019-10-07 8:25 ` [PATCH v2 2/4] module: Fix up module_notifier return values Peter Zijlstra
2019-10-23 19:25 ` Steven Rostedt
2019-10-07 8:25 ` [PATCH v2 3/4] module: Properly propagate MODULE_STATE_COMING failure Peter Zijlstra
2019-10-08 13:08 ` Miroslav Benes
2019-10-07 8:25 ` [PATCH v2 4/4] jump_label,module: Fix module lifetime for __jump_label_mod_text_reserved Peter Zijlstra
2019-10-23 19:29 ` Steven Rostedt
2019-10-07 8:27 ` [PATCH v2 00/13] Add static_call() Peter Zijlstra
2019-10-07 8:27 ` [PATCH v2 01/13] compiler.h: Make __ADDRESSABLE() symbol truly unique Peter Zijlstra
2019-10-07 8:27 ` [PATCH v2 02/13] static_call: Add basic static call infrastructure Peter Zijlstra
2019-10-07 11:33 ` Peter Zijlstra
2019-10-07 8:27 ` [PATCH v2 03/13] static_call: Add inline " Peter Zijlstra
2019-10-07 8:27 ` [PATCH v2 04/13] static_call: Avoid kprobes on inline static_call()s Peter Zijlstra
2019-10-07 8:27 ` [PATCH v2 05/13] x86/static_call: Add out-of-line static call implementation Peter Zijlstra
2019-10-07 8:27 ` [PATCH v2 06/13] x86/static_call: Add inline static call implementation for x86-64 Peter Zijlstra
2019-10-07 8:27 ` [PATCH v2 07/13] static_call: Simple self-test Peter Zijlstra
2019-10-07 8:27 ` [PATCH v2 08/13] tracepoints: Use static_call Peter Zijlstra
2019-10-07 8:27 ` [PATCH v2 09/13] x86/alternatives: Teach text_poke_bp() to emulate RET Peter Zijlstra
2019-10-07 8:27 ` [PATCH v2 10/13] static_call: Add static_cond_call() Peter Zijlstra
2019-10-07 8:27 ` [PATCH v2 11/13] static_call: Handle tail-calls Peter Zijlstra
2019-10-07 8:27 ` [PATCH v2 12/13] static_call: Allow early init Peter Zijlstra
2019-10-07 8:27 ` [RFC][PATCH v2 13/13] x86/perf, static_call: Optimize x86_pmu methods Peter Zijlstra
2019-10-07 11:33 ` [PATCH v2 00/13] Add static_call() Peter Zijlstra
2019-10-07 8:44 ` [RFC][PATCH 0/9] Variable size jump_label support Peter Zijlstra
2019-10-07 8:44 ` [RFC][PATCH 1/9] jump_label, x86: Strip ASM " Peter Zijlstra
2019-10-07 8:44 ` [RFC][PATCH 2/9] jump_label, x86: Factor out the __jump_table generation Peter Zijlstra
2019-10-07 8:44 ` [RFC][PATCH 3/9] jump_label, x86: Remove init NOP optimization Peter Zijlstra
2019-10-07 8:44 ` [RFC][PATCH 4/9] jump_label, x86: Improve error when we fail expected text Peter Zijlstra
2019-10-07 8:44 ` [RFC][PATCH 5/9] jump_label, x86: Introduce jump_entry_size() Peter Zijlstra
2019-10-07 8:44 ` [RFC][PATCH 6/9] jump_label, x86: Add variable length patching support Peter Zijlstra
2019-10-07 8:44 ` [RFC][PATCH 7/9] jump_label,objtool: Validate variable size jump labels Peter Zijlstra
2019-10-07 8:44 ` [RFC][PATCH 8/9] jump_label,objtool: Generate possible statistics Peter Zijlstra
2019-10-07 8:44 ` [RFC][PATCH 9/9] jump_label, x86: Enable JMP8/NOP2 support Peter Zijlstra
2019-10-07 12:07 ` [RFC][PATCH 0/9] Variable size jump_label support Peter Zijlstra
2019-10-07 12:55 ` Ingo Molnar
2019-10-07 15:08 ` Steven Rostedt
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