From mboxrd@z Thu Jan 1 00:00:00 1970 From: Paul Gortmaker Subject: Re: [PATCH v2 2/2] arm64: implement live patching Date: Fri, 15 Jul 2016 12:03:08 -0400 Message-ID: References: <20160627151500.2247A68D20@newverein.lst.de> <20160627151722.B81C968D29@newverein.lst.de> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Return-path: In-Reply-To: <20160627151722.B81C968D29@newverein.lst.de> Sender: linux-arch-owner@vger.kernel.org To: Torsten Duwe Cc: Catalin Marinas , Will Deacon , takahiro.akashi@linaro.org, Jungseok Lee , Arnd Bergmann , Li Bin , Steven Rostedt , Ingo Molnar , Christopher Li , Jiri Kosina , andrew.wafaa@arm.com, "linux-arm-kernel@lists.infradead.org" , LKML , live-patching@vger.kernel.org, linux-arch , linux-sparse@vger.kernel.org List-Id: linux-sparse@vger.kernel.org On Mon, Jun 27, 2016 at 11:17 AM, Torsten Duwe wrote: > On top of FTRACE_WITH_REGS and the klp changes that go into v4.7 > this is straightforward. > > Signed-off-by: Torsten Duwe > --- > arch/arm64/Kconfig | 3 +++ > arch/arm64/include/asm/livepatch.h | 37 +++++++++++++++++++++++++++++++++++++ > arch/arm64/kernel/entry-ftrace.S | 13 +++++++++++++ > 3 files changed, 53 insertions(+) > create mode 100644 arch/arm64/include/asm/livepatch.h > > diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig > index 36a0e26..cb5adf3 100644 > --- a/arch/arm64/Kconfig > +++ b/arch/arm64/Kconfig > @@ -80,6 +80,7 @@ config ARM64 > select HAVE_GENERIC_DMA_COHERENT > select HAVE_HW_BREAKPOINT if PERF_EVENTS > select HAVE_IRQ_TIME_ACCOUNTING > + select HAVE_LIVEPATCH > select HAVE_MEMBLOCK > select HAVE_MEMBLOCK_NODE_MAP if NUMA > select HAVE_PATA_PLATFORM > @@ -1042,4 +1043,6 @@ if CRYPTO > source "arch/arm64/crypto/Kconfig" > endif > > +source "kernel/livepatch/Kconfig" > + > source "lib/Kconfig" > diff --git a/arch/arm64/include/asm/livepatch.h b/arch/arm64/include/asm/livepatch.h > new file mode 100644 > index 0000000..6b9a3d1 > --- /dev/null > +++ b/arch/arm64/include/asm/livepatch.h > @@ -0,0 +1,37 @@ > +/* > + * livepatch.h - arm64-specific Kernel Live Patching Core > + * > + * Copyright (C) 2016 SUSE > + * > + * This program is free software; you can redistribute it and/or > + * modify it under the terms of the GNU General Public License > + * as published by the Free Software Foundation; either version 2 > + * of the License, or (at your option) any later version. > + * > + * This program is distributed in the hope that it will be useful, > + * but WITHOUT ANY WARRANTY; without even the implied warranty of > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the > + * GNU General Public License for more details. > + * > + * You should have received a copy of the GNU General Public License > + * along with this program; if not, see . > + */ > +#ifndef _ASM_ARM64_LIVEPATCH_H > +#define _ASM_ARM64_LIVEPATCH_H > + > +#include > +#include These includes don't look right. It would seem all you need is the one for struct pt_regs. Paul. -- > + > +#ifdef CONFIG_LIVEPATCH > +static inline int klp_check_compiler_support(void) > +{ > + return 0; > +} > + > +static inline void klp_arch_set_pc(struct pt_regs *regs, unsigned long ip) > +{ > + regs->pc = ip; > +} > +#endif /* CONFIG_LIVEPATCH */ > + > +#endif /* _ASM_ARM64_LIVEPATCH_H */ > diff --git a/arch/arm64/kernel/entry-ftrace.S b/arch/arm64/kernel/entry-ftrace.S > index 3ebe791..b166cbf 100644 > --- a/arch/arm64/kernel/entry-ftrace.S > +++ b/arch/arm64/kernel/entry-ftrace.S > @@ -204,6 +204,9 @@ ENTRY(ftrace_caller) > str x9, [sp, #S_LR] > /* The program counter just after the ftrace call site */ > str lr, [sp, #S_PC] > +#if defined(CONFIG_LIVEPATCH) && defined(CONFIG_FUNCTION_GRAPH_TRACER) > + mov x19,lr /* remember old return address */ > +#endif > /* The stack pointer as it was on ftrace_caller entry... */ > add x29, sp, #S_FRAME_SIZE+16 /* ...is also our new FP */ > str x29, [sp, #S_SP] > @@ -219,6 +222,16 @@ ftrace_call: > > bl ftrace_stub > > +#if defined(CONFIG_LIVEPATCH) && defined(CONFIG_FUNCTION_GRAPH_TRACER) > + /* Is the trace function a live patcher an has messed with > + * the return address? > + */ > + ldr x9, [sp, #S_PC] > + cmp x9, x19 /* compare with the value we remembered */ > + /* to not call graph tracer's "call" mechanism twice! */ > + b.eq ftrace_regs_return > +#endif > + > #ifdef CONFIG_FUNCTION_GRAPH_TRACER > .global ftrace_graph_call > ftrace_graph_call: // ftrace_graph_caller(); > -- > 2.6.6 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-arch" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html