Commit-ID: c1c355ce14c037666fbcb9453d9067c86bbdda5c Gitweb: http://git.kernel.org/tip/c1c355ce14c037666fbcb9453d9067c86bbdda5c Author: Josh Poimboeuf <jpoim...@redhat.com> AuthorDate: Thu, 21 Jan 2016 16:49:28 -0600 Committer: Ingo Molnar <mi...@kernel.org> CommitDate: Wed, 24 Feb 2016 08:35:44 +0100
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 <jpoim...@redhat.com> Acked-by: Masami Hiramatsu <masami.hiramatsu...@hitachi.com> Cc: Ananth N Mavinakayanahalli <ana...@in.ibm.com> Cc: Andrew Morton <a...@linux-foundation.org> Cc: Andy Lutomirski <l...@amacapital.net> Cc: Andy Lutomirski <l...@kernel.org> Cc: Anil S Keshavamurthy <anil.s.keshavamur...@intel.com> Cc: Arnaldo Carvalho de Melo <a...@kernel.org> Cc: Bernd Petrovitsch <be...@petrovitsch.priv.at> Cc: Borislav Petkov <b...@alien8.de> Cc: Brian Gerst <brge...@gmail.com> Cc: Chris J Arges <chris.j.ar...@canonical.com> Cc: David S. Miller <da...@davemloft.net> Cc: Denys Vlasenko <dvlas...@redhat.com> Cc: H. Peter Anvin <h...@zytor.com> Cc: Jiri Slaby <jsl...@suse.cz> Cc: Linus Torvalds <torva...@linux-foundation.org> Cc: Michal Marek <mma...@suse.cz> Cc: Namhyung Kim <namhy...@gmail.com> Cc: Pedro Alves <pal...@redhat.com> Cc: Peter Zijlstra <pet...@infradead.org> Cc: Thomas Gleixner <t...@linutronix.de> Cc: live-patch...@vger.kernel.org Link: http://lkml.kernel.org/r/92d921b102fb865a7c254cfde9e4a0a72b9a781e.1453405861.git.jpoim...@redhat.com Signed-off-by: Ingo Molnar <mi...@kernel.org> --- 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); /*
