From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com [148.163.156.1]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 3wD9MB55nrzDqFn for ; Thu, 27 Apr 2017 18:38:14 +1000 (AEST) Received: from pps.filterd (m0098410.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.20/8.16.0.20) with SMTP id v3R8YIKY066325 for ; Thu, 27 Apr 2017 04:38:01 -0400 Received: from e23smtp06.au.ibm.com (e23smtp06.au.ibm.com [202.81.31.148]) by mx0a-001b2d01.pphosted.com with ESMTP id 2a32j3xp7b-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Thu, 27 Apr 2017 04:38:00 -0400 Received: from localhost by e23smtp06.au.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Thu, 27 Apr 2017 18:37:57 +1000 Received: from d23av02.au.ibm.com (d23av02.au.ibm.com [9.190.235.138]) by d23relay09.au.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id v3R8blk051642462 for ; Thu, 27 Apr 2017 18:37:55 +1000 Received: from d23av02.au.ibm.com (localhost [127.0.0.1]) by d23av02.au.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id v3R8bHqP030507 for ; Thu, 27 Apr 2017 18:37:17 +1000 From: "Naveen N. Rao" To: Michael Ellerman Cc: Anton Blanchard , Ananth N Mavinakayanahalli , Masami Hiramatsu , linuxppc-dev@lists.ozlabs.org Subject: [PATCH v2 2/3] powerpc/kprobes: un-blacklist system_call() from kprobes Date: Thu, 27 Apr 2017 14:06:53 +0530 In-Reply-To: References: In-Reply-To: References: Message-Id: List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , It is actually safe to probe system_call() in entry_64.S, but only till .Lsyscall_exit. To allow this, convert .Lsyscall_exit to a non-local symbol __system_call() and blacklist that symbol, rather than system_call(). Reviewed-by: Masami Hiramatsu Signed-off-by: Naveen N. Rao --- arch/powerpc/kernel/entry_64.S | 24 ++++++++++++------------ 1 file changed, 12 insertions(+), 12 deletions(-) diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S index 380361c0bb6a..e030ce34dd66 100644 --- a/arch/powerpc/kernel/entry_64.S +++ b/arch/powerpc/kernel/entry_64.S @@ -176,7 +176,7 @@ system_call: /* label this so stack traces look sane */ mtctr r12 bctrl /* Call handler */ -.Lsyscall_exit: +__system_call: std r3,RESULT(r1) CURRENT_THREAD_INFO(r12, r1) @@ -294,12 +294,12 @@ END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR) blt+ system_call /* Return code is already in r3 thanks to do_syscall_trace_enter() */ - b .Lsyscall_exit + b __system_call .Lsyscall_enosys: li r3,-ENOSYS - b .Lsyscall_exit + b __system_call .Lsyscall_exit_work: #ifdef CONFIG_PPC_BOOK3S @@ -388,7 +388,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR) b . /* prevent speculative execution */ #endif _ASM_NOKPROBE_SYMBOL(system_call_common); -_ASM_NOKPROBE_SYMBOL(system_call); +_ASM_NOKPROBE_SYMBOL(__system_call); /* Save non-volatile GPRs, if not already saved. */ _GLOBAL(save_nvgprs) @@ -413,38 +413,38 @@ _GLOBAL(save_nvgprs) _GLOBAL(ppc_fork) bl save_nvgprs bl sys_fork - b .Lsyscall_exit + b __system_call _GLOBAL(ppc_vfork) bl save_nvgprs bl sys_vfork - b .Lsyscall_exit + b __system_call _GLOBAL(ppc_clone) bl save_nvgprs bl sys_clone - b .Lsyscall_exit + b __system_call _GLOBAL(ppc32_swapcontext) bl save_nvgprs bl compat_sys_swapcontext - b .Lsyscall_exit + b __system_call _GLOBAL(ppc64_swapcontext) bl save_nvgprs bl sys_swapcontext - b .Lsyscall_exit + b __system_call _GLOBAL(ppc_switch_endian) bl save_nvgprs bl sys_switch_endian - b .Lsyscall_exit + b __system_call _GLOBAL(ret_from_fork) bl schedule_tail REST_NVGPRS(r1) li r3,0 - b .Lsyscall_exit + b __system_call _GLOBAL(ret_from_kernel_thread) bl schedule_tail @@ -456,7 +456,7 @@ _GLOBAL(ret_from_kernel_thread) #endif blrl li r3,0 - b .Lsyscall_exit + b __system_call /* * This routine switches between two different tasks. The process -- 2.12.2