| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Date: Thu, 21 Jan 2016 16:49:28 -0600
From: Josh Poimboeuf <jpoimboe@...hat.com>
To: Thomas Gleixner <tglx@...utronix.de>,
Ingo Molnar <mingo@...hat.com>,
"H. Peter Anvin" <hpa@...or.com>, x86@...nel.org
Cc: linux-kernel@...r.kernel.org, live-patching@...r.kernel.org,
Michal Marek <mmarek@...e.cz>,
Peter Zijlstra <peterz@...radead.org>,
Andy Lutomirski <luto@...nel.org>,
Borislav Petkov <bp@...en8.de>,
Linus Torvalds <torvalds@...ux-foundation.org>,
Andi Kleen <andi@...stfloor.org>,
Pedro Alves <palves@...hat.com>,
Namhyung Kim <namhyung@...il.com>,
Bernd Petrovitsch <bernd@...rovitsch.priv.at>,
Chris J Arges <chris.j.arges@...onical.com>,
Andrew Morton <akpm@...ux-foundation.org>,
Jiri Slaby <jslaby@...e.cz>,
Arnaldo Carvalho de Melo <acme@...nel.org>,
Ananth N Mavinakayanahalli <ananth@...ibm.com>,
Anil S Keshavamurthy <anil.s.keshavamurthy@...el.com>,
"David S. Miller" <davem@...emloft.net>,
Masami Hiramatsu <masami.hiramatsu.pt@...achi.com>
Subject: [PATCH 24/33] x86/kprobes: Get rid of kretprobe_trampoline_holder()
The kretprobe_trampoline_holder() wrapper around kretprobe_trampoline()
isn't used anywhere and adds some unnecessary frame pointer instructions
which never execute. Instead, just make kretprobe_trampoline() a proper
ELF function.
Signed-off-by: Josh Poimboeuf <jpoimboe@...hat.com>
Cc: Ananth N Mavinakayanahalli <ananth@...ibm.com>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@...el.com>
Cc: "David S. Miller" <davem@...emloft.net>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@...achi.com>
---
arch/x86/kernel/kprobes/core.c | 57 +++++++++++++++++++++---------------------
1 file changed, 28 insertions(+), 29 deletions(-)
diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c
index 1deffe6..5b187df 100644
--- a/arch/x86/kernel/kprobes/core.c
+++ b/arch/x86/kernel/kprobes/core.c
@@ -671,38 +671,37 @@ NOKPROBE_SYMBOL(kprobe_int3_handler);
* When a retprobed function returns, this code saves registers and
* calls trampoline_handler() runs, which calls the kretprobe's handler.
*/
-static void __used kretprobe_trampoline_holder(void)
-{
- asm volatile (
- ".global kretprobe_trampoline\n"
- "kretprobe_trampoline: \n"
+asm(
+ ".global kretprobe_trampoline\n"
+ ".type kretprobe_trampoline, @function\n"
+ "kretprobe_trampoline:\n"
#ifdef CONFIG_X86_64
- /* We don't bother saving the ss register */
- " pushq %rsp\n"
- " pushfq\n"
- SAVE_REGS_STRING
- " movq %rsp, %rdi\n"
- " call trampoline_handler\n"
- /* Replace saved sp with true return address. */
- " movq %rax, 152(%rsp)\n"
- RESTORE_REGS_STRING
- " popfq\n"
+ /* We don't bother saving the ss register */
+ " pushq %rsp\n"
+ " pushfq\n"
+ SAVE_REGS_STRING
+ " movq %rsp, %rdi\n"
+ " call trampoline_handler\n"
+ /* Replace saved sp with true return address. */
+ " movq %rax, 152(%rsp)\n"
+ RESTORE_REGS_STRING
+ " popfq\n"
#else
- " pushf\n"
- SAVE_REGS_STRING
- " movl %esp, %eax\n"
- " call trampoline_handler\n"
- /* Move flags to cs */
- " movl 56(%esp), %edx\n"
- " movl %edx, 52(%esp)\n"
- /* Replace saved flags with true return address. */
- " movl %eax, 56(%esp)\n"
- RESTORE_REGS_STRING
- " popf\n"
+ " pushf\n"
+ SAVE_REGS_STRING
+ " movl %esp, %eax\n"
+ " call trampoline_handler\n"
+ /* Move flags to cs */
+ " movl 56(%esp), %edx\n"
+ " movl %edx, 52(%esp)\n"
+ /* Replace saved flags with true return address. */
+ " movl %eax, 56(%esp)\n"
+ RESTORE_REGS_STRING
+ " popf\n"
#endif
- " ret\n");
-}
-NOKPROBE_SYMBOL(kretprobe_trampoline_holder);
+ " ret\n"
+ ".size kretprobe_trampoline, .-kretprobe_trampoline\n"
+);
NOKPROBE_SYMBOL(kretprobe_trampoline);
/*
--
2.4.3
Powered by blists - more mailing lists