From: Marco Elver <elver@google.com> To: Peter Zijlstra <peterz@infradead.org> Cc: Nick Desaulniers <ndesaulniers@google.com>, Sami Tolvanen <samitolvanen@google.com>, Masahiro Yamada <masahiroy@kernel.org>, Will Deacon <will@kernel.org>, Greg Kroah-Hartman <gregkh@linuxfoundation.org>, "Paul E. McKenney" <paulmck@kernel.org>, Kees Cook <keescook@chromium.org>, clang-built-linux <clang-built-linux@googlegroups.com>, Kernel Hardening <kernel-hardening@lists.openwall.com>, linux-arch <linux-arch@vger.kernel.org>, Linux ARM <linux-arm-kernel@lists.infradead.org>, Linux Kbuild mailing list <linux-kbuild@vger.kernel.org>, LKML <linux-kernel@vger.kernel.org>, linux-pci@vger.kernel.org, "maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)" <x86@kernel.org> Subject: Re: [PATCH 00/22] add support for Clang LTO Date: Tue, 30 Jun 2020 21:19:31 +0200 [thread overview] Message-ID: <20200630191931.GA884155@elver.google.com> (raw) In-Reply-To: <20200625085745.GD117543@hirez.programming.kicks-ass.net> I was asked for input on this, and after a few days digging through some history, thought I'd comment. Hope you don't mind. On Thu, Jun 25, 2020 at 10:57AM +0200, Peter Zijlstra wrote: > On Thu, Jun 25, 2020 at 10:24:33AM +0200, Peter Zijlstra wrote: > > On Thu, Jun 25, 2020 at 10:03:13AM +0200, Peter Zijlstra wrote: > > > I'm sure Will will respond, but the basic issue is the trainwreck C11 > > > made of dependent loads. > > > > > > Anyway, here's a link to the last time this came up: > > > > > > https://lore.kernel.org/linux-arm-kernel/20171116174830.GX3624@linux.vnet.ibm.com/ > > > > Another good read: > > > > https://lore.kernel.org/lkml/20150520005510.GA23559@linux.vnet.ibm.com/ [...] > Because now the machine can speculate and load now before seq, breaking > the ordering. First of all, I agree with the concerns, but not because of LTO. To set the stage better, and summarize the fundamental problem again: we're in the unfortunate situation that no compiler today has a way to _efficiently_ deal with C11's memory_order_consume [https://lwn.net/Articles/588300/]. If we did, we could just use that and be done with it. But, sadly, that doesn't seem possible right now -- compilers just say consume==acquire. Will suggests doing the same in the kernel: https://lkml.kernel.org/r/20200630173734.14057-19-will@kernel.org What we're most worried about right now is the existence of compiler transformations that could break data dependencies by e.g. turning them into control dependencies. If this is a real worry, I don't think LTO is the magical feature that will uncover those optimizations. If these compiler transformations are real, they also exist in a normal build! And if we are worried about them, we need to stop relying on dependent load ordering across the board; or switch to -O0 for everything. Clearly, we don't want either. Why do we think LTO is special? With LTO, Clang just emits LLVM bitcode instead of ELF objects, and during the linker stage intermodular optimizations across translation unit boundaries are done that might not be possible otherwise [https://llvm.org/docs/LinkTimeOptimization.html]. From the memory model side of things, if we could fully convey our intent to the compiler (the imaginary consume), there would be no problem, because all optimization stages from bitcode generation to the final machine code generation after LTO know about the intended semantics. (Also, keep in mind that LTO is _not_ doing post link optimization of machine code binaries!) But as far as we can tell, there is no evidence of the dreaded "data dependency to control dependency" conversion with LTO that isn't there in non-LTO builds, if it's even there at all. Has the data to control dependency conversion been encountered in the wild? If not, is the resulting reaction an overreaction? If so, we need to be careful blaming LTO for something that it isn't even guilty of. So, we are probably better off untangling LTO from the story: 1. LTO or no LTO does not matter. The LTO series should not get tangled up with memory model issues. 2. The memory model question and problems need to be answered and addressed separately. Thoughts? Thanks, -- Marco
WARNING: multiple messages have this Message-ID (diff)
From: Marco Elver <elver@google.com> To: Peter Zijlstra <peterz@infradead.org> Cc: linux-arch <linux-arch@vger.kernel.org>, "maintainer:X86 ARCHITECTURE \(32-BIT AND 64-BIT\)" <x86@kernel.org>, Kees Cook <keescook@chromium.org>, "Paul E. McKenney" <paulmck@kernel.org>, Kernel Hardening <kernel-hardening@lists.openwall.com>, Greg Kroah-Hartman <gregkh@linuxfoundation.org>, Masahiro Yamada <masahiroy@kernel.org>, Linux Kbuild mailing list <linux-kbuild@vger.kernel.org>, Nick Desaulniers <ndesaulniers@google.com>, LKML <linux-kernel@vger.kernel.org>, clang-built-linux <clang-built-linux@googlegroups.com>, Sami Tolvanen <samitolvanen@google.com>, linux-pci@vger.kernel.org, Will Deacon <will@kernel.org>, Linux ARM <linux-arm-kernel@lists.infradead.org> Subject: Re: [PATCH 00/22] add support for Clang LTO Date: Tue, 30 Jun 2020 21:19:31 +0200 [thread overview] Message-ID: <20200630191931.GA884155@elver.google.com> (raw) In-Reply-To: <20200625085745.GD117543@hirez.programming.kicks-ass.net> I was asked for input on this, and after a few days digging through some history, thought I'd comment. Hope you don't mind. On Thu, Jun 25, 2020 at 10:57AM +0200, Peter Zijlstra wrote: > On Thu, Jun 25, 2020 at 10:24:33AM +0200, Peter Zijlstra wrote: > > On Thu, Jun 25, 2020 at 10:03:13AM +0200, Peter Zijlstra wrote: > > > I'm sure Will will respond, but the basic issue is the trainwreck C11 > > > made of dependent loads. > > > > > > Anyway, here's a link to the last time this came up: > > > > > > https://lore.kernel.org/linux-arm-kernel/20171116174830.GX3624@linux.vnet.ibm.com/ > > > > Another good read: > > > > https://lore.kernel.org/lkml/20150520005510.GA23559@linux.vnet.ibm.com/ [...] > Because now the machine can speculate and load now before seq, breaking > the ordering. First of all, I agree with the concerns, but not because of LTO. To set the stage better, and summarize the fundamental problem again: we're in the unfortunate situation that no compiler today has a way to _efficiently_ deal with C11's memory_order_consume [https://lwn.net/Articles/588300/]. If we did, we could just use that and be done with it. But, sadly, that doesn't seem possible right now -- compilers just say consume==acquire. Will suggests doing the same in the kernel: https://lkml.kernel.org/r/20200630173734.14057-19-will@kernel.org What we're most worried about right now is the existence of compiler transformations that could break data dependencies by e.g. turning them into control dependencies. If this is a real worry, I don't think LTO is the magical feature that will uncover those optimizations. If these compiler transformations are real, they also exist in a normal build! And if we are worried about them, we need to stop relying on dependent load ordering across the board; or switch to -O0 for everything. Clearly, we don't want either. Why do we think LTO is special? With LTO, Clang just emits LLVM bitcode instead of ELF objects, and during the linker stage intermodular optimizations across translation unit boundaries are done that might not be possible otherwise [https://llvm.org/docs/LinkTimeOptimization.html]. From the memory model side of things, if we could fully convey our intent to the compiler (the imaginary consume), there would be no problem, because all optimization stages from bitcode generation to the final machine code generation after LTO know about the intended semantics. (Also, keep in mind that LTO is _not_ doing post link optimization of machine code binaries!) But as far as we can tell, there is no evidence of the dreaded "data dependency to control dependency" conversion with LTO that isn't there in non-LTO builds, if it's even there at all. Has the data to control dependency conversion been encountered in the wild? If not, is the resulting reaction an overreaction? If so, we need to be careful blaming LTO for something that it isn't even guilty of. So, we are probably better off untangling LTO from the story: 1. LTO or no LTO does not matter. The LTO series should not get tangled up with memory model issues. 2. The memory model question and problems need to be answered and addressed separately. Thoughts? Thanks, -- Marco _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2020-06-30 19:19 UTC|newest] Thread overview: 520+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-06-24 20:31 [PATCH 00/22] add support for Clang LTO Sami Tolvanen 2020-06-24 20:31 ` Sami Tolvanen 2020-06-24 20:31 ` Sami Tolvanen 2020-06-24 20:31 ` [PATCH 01/22] objtool: use sh_info to find the base for .rela sections Sami Tolvanen 2020-06-24 20:31 ` Sami Tolvanen 2020-06-24 20:31 ` Sami Tolvanen 2020-06-24 20:31 ` [PATCH 02/22] kbuild: add support for Clang LTO Sami Tolvanen 2020-06-24 20:31 ` Sami Tolvanen 2020-06-24 20:31 ` Sami Tolvanen 2020-06-24 20:53 ` Nick Desaulniers 2020-06-24 20:53 ` Nick Desaulniers 2020-06-24 20:53 ` Nick Desaulniers 2020-06-24 21:29 ` Sami Tolvanen 2020-06-24 21:29 ` Sami Tolvanen 2020-06-25 2:26 ` Nathan Chancellor 2020-06-25 2:26 ` Nathan Chancellor 2020-06-25 16:13 ` Sami Tolvanen 2020-06-25 16:13 ` Sami Tolvanen 2020-06-24 20:31 ` [PATCH 03/22] kbuild: lto: fix module versioning Sami Tolvanen 2020-06-24 20:31 ` Sami Tolvanen 2020-06-24 20:31 ` Sami Tolvanen 2020-06-24 20:31 ` [PATCH 04/22] kbuild: lto: fix recordmcount Sami Tolvanen 2020-06-24 20:31 ` Sami Tolvanen 2020-06-24 20:31 ` Sami Tolvanen 2020-06-24 21:27 ` Peter Zijlstra 2020-06-24 21:27 ` Peter Zijlstra 2020-06-24 21:45 ` Sami Tolvanen 2020-06-24 21:45 ` Sami Tolvanen 2020-06-25 7:45 ` Peter Zijlstra 2020-06-25 7:45 ` Peter Zijlstra 2020-06-25 16:15 ` Sami Tolvanen 2020-06-25 16:15 ` Sami Tolvanen 2020-06-25 20:02 ` [RFC][PATCH] objtool,x86_64: Replace recordmcount with objtool Peter Zijlstra 2020-06-25 20:02 ` Peter Zijlstra 2020-06-25 20:54 ` Nick Desaulniers 2020-06-25 20:54 ` Nick Desaulniers 2020-06-25 20:54 ` Nick Desaulniers 2020-06-25 22:40 ` Sami Tolvanen 2020-06-25 22:40 ` Sami Tolvanen 2020-06-26 11:29 ` Peter Zijlstra 2020-06-26 11:29 ` Peter Zijlstra 2020-06-26 11:42 ` Peter Zijlstra 2020-06-26 11:42 ` Peter Zijlstra 2020-07-17 17:28 ` Sami Tolvanen 2020-07-17 17:28 ` Sami Tolvanen 2020-07-17 17:28 ` Sami Tolvanen 2020-07-17 17:36 ` Steven Rostedt 2020-07-17 17:36 ` Steven Rostedt 2020-07-17 17:47 ` Sami Tolvanen 2020-07-17 17:47 ` Sami Tolvanen 2020-07-17 17:47 ` Sami Tolvanen 2020-07-17 18:05 ` Steven Rostedt 2020-07-17 18:05 ` Steven Rostedt 2020-07-20 16:52 ` Sami Tolvanen 2020-07-20 16:52 ` Sami Tolvanen 2020-07-20 16:52 ` Sami Tolvanen 2020-07-22 17:58 ` Steven Rostedt 2020-07-22 17:58 ` Steven Rostedt 2020-07-22 18:07 ` Sami Tolvanen 2020-07-22 18:07 ` Sami Tolvanen 2020-07-22 18:07 ` Sami Tolvanen 2020-07-22 17:55 ` Steven Rostedt 2020-07-22 17:55 ` Steven Rostedt 2020-07-22 18:41 ` Peter Zijlstra 2020-07-22 18:41 ` Peter Zijlstra 2020-07-22 19:09 ` Steven Rostedt 2020-07-22 19:09 ` Steven Rostedt 2020-07-22 20:03 ` Sami Tolvanen 2020-07-22 20:03 ` Sami Tolvanen 2020-07-22 20:03 ` Sami Tolvanen 2020-07-22 23:56 ` Peter Zijlstra 2020-07-22 23:56 ` Peter Zijlstra 2020-07-23 0:06 ` Steven Rostedt 2020-07-23 0:06 ` Steven Rostedt 2020-08-06 22:09 ` Sami Tolvanen 2020-08-06 22:09 ` Sami Tolvanen 2020-06-24 20:31 ` [PATCH 05/22] kbuild: lto: postpone objtool Sami Tolvanen 2020-06-24 20:31 ` Sami Tolvanen 2020-06-24 20:31 ` Sami Tolvanen 2020-06-24 21:19 ` Peter Zijlstra 2020-06-24 21:19 ` Peter Zijlstra 2020-06-24 21:49 ` Sami Tolvanen 2020-06-24 21:49 ` Sami Tolvanen 2020-06-25 7:47 ` Peter Zijlstra 2020-06-25 7:47 ` Peter Zijlstra 2020-06-25 16:22 ` Sami Tolvanen 2020-06-25 16:22 ` Sami Tolvanen 2020-06-25 18:33 ` Peter Zijlstra 2020-06-25 18:33 ` Peter Zijlstra 2020-06-25 19:32 ` Sami Tolvanen 2020-06-25 19:32 ` Sami Tolvanen 2020-06-24 20:31 ` [PATCH 06/22] kbuild: lto: limit inlining Sami Tolvanen 2020-06-24 20:31 ` Sami Tolvanen 2020-06-24 20:31 ` Sami Tolvanen 2020-06-24 21:20 ` Peter Zijlstra 2020-06-24 21:20 ` Peter Zijlstra 2020-06-24 23:37 ` Sami Tolvanen 2020-06-24 23:37 ` Sami Tolvanen 2020-06-24 20:31 ` [PATCH 07/22] kbuild: lto: merge module sections Sami Tolvanen 2020-06-24 20:31 ` Sami Tolvanen 2020-06-24 20:31 ` Sami Tolvanen 2020-06-24 21:01 ` Nick Desaulniers 2020-06-24 21:01 ` Nick Desaulniers 2020-06-24 21:01 ` Nick Desaulniers 2020-06-24 21:31 ` Sami Tolvanen 2020-06-24 21:31 ` Sami Tolvanen 2020-06-24 20:31 ` [PATCH 08/22] kbuild: lto: remove duplicate dependencies from .mod files Sami Tolvanen 2020-06-24 20:31 ` Sami Tolvanen 2020-06-24 20:31 ` Sami Tolvanen 2020-06-24 21:13 ` Nick Desaulniers 2020-06-24 21:13 ` Nick Desaulniers 2020-06-24 21:13 ` Nick Desaulniers 2020-06-24 20:31 ` [PATCH 09/22] init: lto: ensure initcall ordering Sami Tolvanen 2020-06-24 20:31 ` Sami Tolvanen 2020-06-24 20:31 ` Sami Tolvanen 2020-06-25 0:58 ` kernel test robot 2020-06-25 0:58 ` kernel test robot 2020-06-25 0:58 ` kernel test robot 2020-06-25 4:19 ` kernel test robot 2020-06-25 4:19 ` kernel test robot 2020-06-25 4:19 ` kernel test robot 2020-06-24 20:31 ` [PATCH 10/22] init: lto: fix PREL32 relocations Sami Tolvanen 2020-06-24 20:31 ` Sami Tolvanen 2020-06-24 20:31 ` Sami Tolvanen 2020-06-24 20:31 ` [PATCH 11/22] pci: " Sami Tolvanen 2020-06-24 20:31 ` Sami Tolvanen 2020-06-24 20:31 ` Sami Tolvanen 2020-06-24 22:49 ` kernel test robot 2020-06-24 22:49 ` kernel test robot 2020-06-24 22:49 ` kernel test robot 2020-06-24 23:03 ` Nick Desaulniers 2020-06-24 23:03 ` Nick Desaulniers 2020-06-24 23:03 ` Nick Desaulniers 2020-06-24 23:03 ` Nick Desaulniers 2020-06-24 23:21 ` Sami Tolvanen 2020-06-24 23:21 ` Sami Tolvanen 2020-06-24 23:21 ` Sami Tolvanen 2020-07-17 20:26 ` Bjorn Helgaas 2020-07-17 20:26 ` Bjorn Helgaas 2020-07-22 18:15 ` Sami Tolvanen 2020-07-22 18:15 ` Sami Tolvanen 2020-07-22 18:15 ` Sami Tolvanen 2020-06-24 20:31 ` [PATCH 12/22] modpost: lto: strip .lto from module names Sami Tolvanen 2020-06-24 20:31 ` Sami Tolvanen 2020-06-24 20:31 ` Sami Tolvanen 2020-06-24 22:05 ` Nick Desaulniers 2020-06-24 22:05 ` Nick Desaulniers 2020-06-24 22:05 ` Nick Desaulniers 2020-06-24 20:31 ` [PATCH 13/22] scripts/mod: disable LTO for empty.c Sami Tolvanen 2020-06-24 20:31 ` Sami Tolvanen 2020-06-24 20:31 ` Sami Tolvanen 2020-06-24 20:57 ` Nick Desaulniers 2020-06-24 20:57 ` Nick Desaulniers 2020-06-24 20:57 ` Nick Desaulniers 2020-06-24 20:31 ` [PATCH 14/22] efi/libstub: disable LTO Sami Tolvanen 2020-06-24 20:31 ` Sami Tolvanen 2020-06-24 20:31 ` Sami Tolvanen 2020-06-24 20:31 ` [PATCH 15/22] drivers/misc/lkdtm: disable LTO for rodata.o Sami Tolvanen 2020-06-24 20:31 ` Sami Tolvanen 2020-06-24 20:31 ` Sami Tolvanen 2020-06-24 20:31 ` [PATCH 16/22] arm64: export CC_USING_PATCHABLE_FUNCTION_ENTRY Sami Tolvanen 2020-06-24 20:31 ` Sami Tolvanen 2020-06-24 20:31 ` Sami Tolvanen 2020-06-24 20:31 ` [PATCH 17/22] arm64: vdso: disable LTO Sami Tolvanen 2020-06-24 20:31 ` Sami Tolvanen 2020-06-24 20:31 ` Sami Tolvanen 2020-06-24 20:58 ` Nick Desaulniers 2020-06-24 20:58 ` Nick Desaulniers 2020-06-24 20:58 ` Nick Desaulniers 2020-06-24 21:09 ` Nick Desaulniers 2020-06-24 21:09 ` Nick Desaulniers 2020-06-24 21:09 ` Nick Desaulniers 2020-06-24 23:51 ` Andi Kleen 2020-06-24 23:51 ` Andi Kleen 2020-06-24 21:52 ` Sami Tolvanen 2020-06-24 21:52 ` Sami Tolvanen 2020-06-24 23:05 ` Nick Desaulniers 2020-06-24 23:05 ` Nick Desaulniers 2020-06-24 23:05 ` Nick Desaulniers 2020-06-24 23:39 ` Sami Tolvanen 2020-06-24 23:39 ` Sami Tolvanen 2020-06-24 20:31 ` [PATCH 18/22] arm64: allow LTO_CLANG and THINLTO to be selected Sami Tolvanen 2020-06-24 20:31 ` Sami Tolvanen 2020-06-24 20:31 ` Sami Tolvanen 2020-06-24 20:31 ` [PATCH 19/22] x86, vdso: disable LTO only for vDSO Sami Tolvanen 2020-06-24 20:31 ` Sami Tolvanen 2020-06-24 20:31 ` Sami Tolvanen 2020-06-24 20:31 ` [PATCH 20/22] x86, ftrace: disable recordmcount for ftrace_make_nop Sami Tolvanen 2020-06-24 20:31 ` Sami Tolvanen 2020-06-24 20:31 ` Sami Tolvanen 2020-06-24 20:31 ` [PATCH 21/22] x86, relocs: Ignore L4_PAGE_OFFSET relocations Sami Tolvanen 2020-06-24 20:31 ` Sami Tolvanen 2020-06-24 20:31 ` Sami Tolvanen 2020-06-24 20:32 ` [PATCH 22/22] x86, build: allow LTO_CLANG and THINLTO to be selected Sami Tolvanen 2020-06-24 20:32 ` Sami Tolvanen 2020-06-24 20:32 ` Sami Tolvanen 2020-06-24 21:15 ` [PATCH 00/22] add support for Clang LTO Peter Zijlstra 2020-06-24 21:15 ` Peter Zijlstra 2020-06-24 21:30 ` Sami Tolvanen 2020-06-24 21:30 ` Sami Tolvanen 2020-06-25 8:27 ` Will Deacon 2020-06-25 8:27 ` Will Deacon 2020-06-24 21:31 ` Nick Desaulniers 2020-06-24 21:31 ` Nick Desaulniers 2020-06-24 21:31 ` Nick Desaulniers 2020-06-25 8:03 ` Peter Zijlstra 2020-06-25 8:03 ` Peter Zijlstra 2020-06-25 8:24 ` Peter Zijlstra 2020-06-25 8:24 ` Peter Zijlstra 2020-06-25 8:57 ` Peter Zijlstra 2020-06-25 8:57 ` Peter Zijlstra 2020-06-30 19:19 ` Marco Elver [this message] 2020-06-30 19:19 ` Marco Elver 2020-06-30 20:12 ` Peter Zijlstra 2020-06-30 20:12 ` Peter Zijlstra 2020-06-30 20:30 ` Paul E. McKenney 2020-06-30 20:30 ` Paul E. McKenney 2020-07-01 9:10 ` Peter Zijlstra 2020-07-01 9:10 ` Peter Zijlstra 2020-07-01 14:20 ` David Laight 2020-07-01 14:20 ` David Laight 2020-07-01 16:06 ` Paul E. McKenney 2020-07-01 16:06 ` Paul E. McKenney 2020-07-02 9:37 ` David Laight 2020-07-02 9:37 ` David Laight 2020-07-02 18:00 ` Paul E. McKenney 2020-07-02 18:00 ` Paul E. McKenney 2020-07-01 9:41 ` Marco Elver 2020-07-01 9:41 ` Marco Elver 2020-07-01 9:41 ` Marco Elver 2020-07-01 10:03 ` Will Deacon 2020-07-01 10:03 ` Will Deacon 2020-07-01 11:40 ` Peter Zijlstra 2020-07-01 11:40 ` Peter Zijlstra 2020-07-01 14:06 ` Paul E. McKenney 2020-07-01 14:06 ` Paul E. McKenney 2020-07-01 15:05 ` Peter Zijlstra 2020-07-01 15:05 ` Peter Zijlstra 2020-07-01 16:03 ` Paul E. McKenney 2020-07-01 16:03 ` Paul E. McKenney 2020-07-02 8:20 ` Peter Zijlstra 2020-07-02 8:20 ` Peter Zijlstra 2020-07-02 17:59 ` Paul E. McKenney 2020-07-02 17:59 ` Paul E. McKenney 2020-07-03 13:13 ` Peter Zijlstra 2020-07-03 13:13 ` Peter Zijlstra 2020-07-03 13:25 ` Peter Zijlstra 2020-07-03 13:25 ` Peter Zijlstra 2020-07-03 14:51 ` Paul E. McKenney 2020-07-03 14:51 ` Paul E. McKenney 2020-07-03 14:42 ` Paul E. McKenney 2020-07-03 14:42 ` Paul E. McKenney 2020-07-06 16:26 ` Paul E. McKenney 2020-07-06 16:26 ` Paul E. McKenney 2020-07-06 18:29 ` Peter Zijlstra 2020-07-06 18:29 ` Peter Zijlstra 2020-07-06 18:39 ` Paul E. McKenney 2020-07-06 18:39 ` Paul E. McKenney 2020-07-06 19:40 ` Peter Zijlstra 2020-07-06 19:40 ` Peter Zijlstra 2020-07-06 23:41 ` Paul E. McKenney 2020-07-06 23:41 ` Paul E. McKenney 2020-06-28 16:56 ` Masahiro Yamada 2020-06-28 16:56 ` Masahiro Yamada 2020-06-28 16:56 ` Masahiro Yamada 2020-06-29 23:20 ` Sami Tolvanen 2020-06-29 23:20 ` Sami Tolvanen 2020-07-07 15:51 ` Sami Tolvanen 2020-07-07 15:51 ` Sami Tolvanen 2020-07-07 16:05 ` Sami Tolvanen 2020-07-07 16:05 ` Sami Tolvanen 2020-07-07 16:56 ` Jakub Kicinski 2020-07-07 16:56 ` Jakub Kicinski 2020-07-07 17:17 ` Nick Desaulniers 2020-07-07 17:17 ` Nick Desaulniers 2020-07-07 17:17 ` Nick Desaulniers 2020-07-07 17:30 ` Jakub Kicinski 2020-07-07 17:30 ` Jakub Kicinski 2020-07-11 16:32 ` Paul Menzel 2020-07-11 16:32 ` Paul Menzel 2020-07-11 16:32 ` Paul Menzel 2020-07-12 8:59 ` Sedat Dilek 2020-07-12 8:59 ` Sedat Dilek 2020-07-12 8:59 ` Sedat Dilek 2020-07-12 18:40 ` Nathan Chancellor 2020-07-12 18:40 ` Nathan Chancellor 2020-07-14 9:44 ` Sedat Dilek 2020-07-14 9:44 ` Sedat Dilek 2020-07-14 9:44 ` Sedat Dilek 2020-07-14 17:54 ` Nick Desaulniers 2020-07-14 17:54 ` Nick Desaulniers 2020-07-14 17:54 ` Nick Desaulniers 2020-07-12 23:34 ` Sami Tolvanen 2020-07-12 23:34 ` Sami Tolvanen 2020-07-12 23:34 ` Sami Tolvanen 2020-07-14 12:16 ` Paul Menzel 2020-07-14 12:16 ` Paul Menzel 2020-07-14 12:35 ` Sedat Dilek 2020-07-14 12:35 ` Sedat Dilek 2020-07-14 12:35 ` Sedat Dilek 2020-07-14 13:40 ` Paul Menzel 2020-09-03 20:30 ` [PATCH v2 00/28] Add " Sami Tolvanen 2020-09-03 20:30 ` Sami Tolvanen 2020-09-03 20:30 ` Sami Tolvanen 2020-09-03 20:30 ` [PATCH v2 01/28] x86/boot/compressed: Disable relocation relaxation Sami Tolvanen 2020-09-03 20:30 ` Sami Tolvanen 2020-09-03 20:30 ` Sami Tolvanen 2020-09-03 21:44 ` Kees Cook 2020-09-03 21:44 ` Kees Cook 2020-09-03 23:42 ` Arvind Sankar 2020-09-03 23:42 ` Arvind Sankar 2020-09-04 7:14 ` Nathan Chancellor 2020-09-04 7:14 ` Nathan Chancellor 2020-09-06 3:16 ` Sasha Levin 2020-09-03 20:30 ` [PATCH v2 02/28] x86/asm: Replace __force_order with memory clobber Sami Tolvanen 2020-09-03 20:30 ` Sami Tolvanen 2020-09-03 20:30 ` Sami Tolvanen 2020-09-03 21:45 ` Kees Cook 2020-09-03 21:45 ` Kees Cook 2020-09-03 20:30 ` [PATCH v2 03/28] lib/string.c: implement stpcpy Sami Tolvanen 2020-09-03 20:30 ` Sami Tolvanen 2020-09-03 20:30 ` Sami Tolvanen 2020-09-03 21:47 ` Kees Cook 2020-09-03 21:47 ` Kees Cook 2020-09-06 3:16 ` Sasha Levin 2020-09-03 20:30 ` [PATCH v2 04/28] RAS/CEC: Fix cec_init() prototype Sami Tolvanen 2020-09-03 20:30 ` Sami Tolvanen 2020-09-03 20:30 ` Sami Tolvanen 2020-09-03 21:50 ` Kees Cook 2020-09-03 21:50 ` Kees Cook 2020-09-03 20:30 ` [PATCH v2 05/28] objtool: Add a pass for generating __mcount_loc Sami Tolvanen 2020-09-03 20:30 ` Sami Tolvanen 2020-09-03 20:30 ` Sami Tolvanen 2020-09-03 21:51 ` Kees Cook 2020-09-03 21:51 ` Kees Cook 2020-09-03 22:03 ` Sami Tolvanen 2020-09-03 22:03 ` Sami Tolvanen 2020-09-03 22:03 ` Sami Tolvanen 2020-09-04 9:31 ` peterz 2020-09-04 9:31 ` peterz 2020-09-10 18:29 ` Kees Cook 2020-09-10 18:29 ` Kees Cook 2020-09-03 20:30 ` [PATCH v2 06/28] objtool: Don't autodetect vmlinux.o Sami Tolvanen 2020-09-03 20:30 ` Sami Tolvanen 2020-09-03 20:30 ` Sami Tolvanen 2020-09-03 21:52 ` Kees Cook 2020-09-03 21:52 ` Kees Cook 2020-09-03 20:30 ` [PATCH v2 07/28] kbuild: add support for objtool mcount Sami Tolvanen 2020-09-03 20:30 ` Sami Tolvanen 2020-09-03 20:30 ` Sami Tolvanen 2020-09-03 21:56 ` Kees Cook 2020-09-03 21:56 ` Kees Cook 2020-09-03 20:30 ` [PATCH v2 08/28] x86, build: use " Sami Tolvanen 2020-09-03 20:30 ` Sami Tolvanen 2020-09-03 20:30 ` Sami Tolvanen 2020-09-03 21:58 ` Kees Cook 2020-09-03 21:58 ` Kees Cook 2020-09-03 22:11 ` Sami Tolvanen 2020-09-03 22:11 ` Sami Tolvanen 2020-09-03 22:11 ` Sami Tolvanen 2020-09-03 20:30 ` [PATCH v2 09/28] kbuild: add support for Clang LTO Sami Tolvanen 2020-09-03 20:30 ` Sami Tolvanen 2020-09-03 20:30 ` Sami Tolvanen 2020-09-03 22:08 ` Kees Cook 2020-09-03 22:08 ` Kees Cook 2020-09-08 17:02 ` Sami Tolvanen 2020-09-08 17:02 ` Sami Tolvanen 2020-09-05 19:36 ` Masahiro Yamada 2020-09-05 19:36 ` Masahiro Yamada 2020-09-08 17:10 ` Sami Tolvanen 2020-09-08 17:10 ` Sami Tolvanen 2020-09-05 20:17 ` Masahiro Yamada 2020-09-05 20:17 ` Masahiro Yamada 2020-09-08 17:14 ` Sami Tolvanen 2020-09-08 17:14 ` Sami Tolvanen 2020-09-07 15:30 ` Masahiro Yamada 2020-09-07 15:30 ` Masahiro Yamada 2020-09-08 17:30 ` Sami Tolvanen 2020-09-08 17:30 ` Sami Tolvanen 2020-09-03 20:30 ` [PATCH v2 10/28] kbuild: lto: fix module versioning Sami Tolvanen 2020-09-03 20:30 ` Sami Tolvanen 2020-09-03 20:30 ` Sami Tolvanen 2020-09-03 22:11 ` Kees Cook 2020-09-03 22:11 ` Kees Cook 2020-09-08 18:23 ` Sami Tolvanen 2020-09-08 18:23 ` Sami Tolvanen 2020-09-03 20:30 ` [PATCH v2 11/28] kbuild: lto: postpone objtool Sami Tolvanen 2020-09-03 20:30 ` Sami Tolvanen 2020-09-03 20:30 ` Sami Tolvanen 2020-09-03 22:19 ` Kees Cook 2020-09-03 22:19 ` Kees Cook 2020-09-08 20:56 ` Sami Tolvanen 2020-09-08 20:56 ` Sami Tolvanen 2020-09-03 20:30 ` [PATCH v2 12/28] kbuild: lto: limit inlining Sami Tolvanen 2020-09-03 20:30 ` Sami Tolvanen 2020-09-03 20:30 ` Sami Tolvanen 2020-09-03 22:20 ` Kees Cook 2020-09-03 22:20 ` Kees Cook 2020-09-03 20:30 ` [PATCH v2 13/28] kbuild: lto: merge module sections Sami Tolvanen 2020-09-03 20:30 ` Sami Tolvanen 2020-09-03 20:30 ` Sami Tolvanen 2020-09-03 22:23 ` Kees Cook 2020-09-03 22:23 ` Kees Cook 2020-09-07 15:25 ` Masahiro Yamada 2020-09-07 15:25 ` Masahiro Yamada 2020-09-08 21:07 ` Sami Tolvanen 2020-09-08 21:07 ` Sami Tolvanen 2020-09-03 20:30 ` [PATCH v2 14/28] kbuild: lto: remove duplicate dependencies from .mod files Sami Tolvanen 2020-09-03 20:30 ` Sami Tolvanen 2020-09-03 20:30 ` Sami Tolvanen 2020-09-03 22:29 ` Kees Cook 2020-09-03 22:29 ` Kees Cook 2020-09-03 20:30 ` [PATCH v2 15/28] init: lto: ensure initcall ordering Sami Tolvanen 2020-09-03 20:30 ` Sami Tolvanen 2020-09-03 20:30 ` Sami Tolvanen 2020-09-03 22:40 ` Kees Cook 2020-09-03 22:40 ` Kees Cook 2020-09-08 21:16 ` Sami Tolvanen 2020-09-08 21:16 ` Sami Tolvanen 2020-09-10 9:25 ` David Woodhouse 2020-09-10 9:25 ` David Woodhouse 2020-09-10 9:25 ` David Woodhouse 2020-09-10 15:07 ` Sami Tolvanen 2020-09-10 15:07 ` Sami Tolvanen 2020-09-03 20:30 ` [PATCH v2 16/28] init: lto: fix PREL32 relocations Sami Tolvanen 2020-09-03 20:30 ` Sami Tolvanen 2020-09-03 20:30 ` Sami Tolvanen 2020-09-03 22:41 ` Kees Cook 2020-09-03 22:41 ` Kees Cook 2020-09-06 3:16 ` Sasha Levin 2020-09-03 20:30 ` [PATCH v2 17/28] PCI: Fix PREL32 relocations for LTO Sami Tolvanen 2020-09-03 20:30 ` Sami Tolvanen 2020-09-03 20:30 ` Sami Tolvanen 2020-09-03 22:42 ` Kees Cook 2020-09-03 22:42 ` Kees Cook 2020-09-03 20:30 ` [PATCH v2 18/28] modpost: lto: strip .lto from module names Sami Tolvanen 2020-09-03 20:30 ` Sami Tolvanen 2020-09-03 20:30 ` Sami Tolvanen 2020-09-03 22:42 ` Kees Cook 2020-09-03 22:42 ` Kees Cook 2020-09-03 20:30 ` [PATCH v2 19/28] scripts/mod: disable LTO for empty.c Sami Tolvanen 2020-09-03 20:30 ` Sami Tolvanen 2020-09-03 20:30 ` Sami Tolvanen 2020-09-03 22:43 ` Kees Cook 2020-09-03 22:43 ` Kees Cook 2020-09-03 20:30 ` [PATCH v2 20/28] efi/libstub: disable LTO Sami Tolvanen 2020-09-03 20:30 ` Sami Tolvanen 2020-09-03 20:30 ` Sami Tolvanen 2020-09-03 22:43 ` Kees Cook 2020-09-03 22:43 ` Kees Cook 2020-09-03 20:30 ` [PATCH v2 21/28] drivers/misc/lkdtm: disable LTO for rodata.o Sami Tolvanen 2020-09-03 20:30 ` Sami Tolvanen 2020-09-03 20:30 ` Sami Tolvanen 2020-09-03 20:30 ` [PATCH v2 22/28] arm64: export CC_USING_PATCHABLE_FUNCTION_ENTRY Sami Tolvanen 2020-09-03 20:30 ` Sami Tolvanen 2020-09-03 20:30 ` Sami Tolvanen 2020-09-03 22:44 ` Kees Cook 2020-09-03 22:44 ` Kees Cook 2020-09-08 21:23 ` Sami Tolvanen 2020-09-08 21:23 ` Sami Tolvanen 2020-09-03 20:30 ` [PATCH v2 23/28] arm64: vdso: disable LTO Sami Tolvanen 2020-09-03 20:30 ` Sami Tolvanen 2020-09-03 20:30 ` Sami Tolvanen 2020-09-03 22:45 ` Kees Cook 2020-09-03 22:45 ` Kees Cook 2020-09-03 20:30 ` [PATCH v2 24/28] KVM: arm64: disable LTO for the nVHE directory Sami Tolvanen 2020-09-03 20:30 ` Sami Tolvanen 2020-09-03 20:30 ` Sami Tolvanen 2020-09-03 22:45 ` Kees Cook 2020-09-03 22:45 ` Kees Cook 2020-09-03 20:30 ` [PATCH v2 25/28] arm64: allow LTO_CLANG and THINLTO to be selected Sami Tolvanen 2020-09-03 20:30 ` Sami Tolvanen 2020-09-03 20:30 ` Sami Tolvanen 2020-09-03 22:45 ` Kees Cook 2020-09-03 22:45 ` Kees Cook 2020-09-03 20:30 ` [PATCH v2 26/28] x86, vdso: disable LTO only for vDSO Sami Tolvanen 2020-09-03 20:30 ` Sami Tolvanen 2020-09-03 20:30 ` Sami Tolvanen 2020-09-03 22:46 ` Kees Cook 2020-09-03 22:46 ` Kees Cook 2020-09-03 20:30 ` [PATCH v2 27/28] x86, relocs: Ignore L4_PAGE_OFFSET relocations Sami Tolvanen 2020-09-03 20:30 ` Sami Tolvanen 2020-09-03 20:30 ` Sami Tolvanen 2020-09-03 22:47 ` Kees Cook 2020-09-03 22:47 ` Kees Cook 2020-09-08 23:28 ` Sami Tolvanen 2020-09-08 23:28 ` Sami Tolvanen 2020-09-03 20:30 ` [PATCH v2 28/28] x86, build: allow LTO_CLANG and THINLTO to be selected Sami Tolvanen 2020-09-03 20:30 ` Sami Tolvanen 2020-09-03 20:30 ` Sami Tolvanen 2020-09-03 22:48 ` Kees Cook 2020-09-03 22:48 ` Kees Cook 2020-09-03 23:34 ` [PATCH v2 00/28] Add support for Clang LTO Kees Cook 2020-09-03 23:34 ` Kees Cook 2020-09-04 4:45 ` Nathan Chancellor 2020-09-04 4:45 ` Nathan Chancellor 2020-09-03 23:38 ` Kees Cook 2020-09-03 23:38 ` Kees Cook 2020-09-04 7:53 ` Sedat Dilek 2020-09-04 7:53 ` Sedat Dilek 2020-09-04 7:53 ` Sedat Dilek 2020-09-04 8:55 ` peterz 2020-09-04 8:55 ` peterz 2020-09-04 9:08 ` Sedat Dilek 2020-09-04 9:08 ` Sedat Dilek 2020-09-04 9:08 ` Sedat Dilek 2020-09-06 0:24 ` Masahiro Yamada 2020-09-06 0:24 ` Masahiro Yamada 2020-09-08 23:46 ` Sami Tolvanen 2020-09-08 23:46 ` Sami Tolvanen 2020-09-10 1:18 ` Masahiro Yamada 2020-09-10 1:18 ` Masahiro Yamada 2020-09-10 15:17 ` Sami Tolvanen 2020-09-10 15:17 ` Sami Tolvanen 2020-09-10 18:18 ` Kees Cook 2020-09-10 18:18 ` Kees Cook 2020-09-10 17:46 ` Nick Desaulniers 2020-09-10 18:07 ` Masahiro Yamada 2020-09-22 16:27 ` [EXTERNAL] " Ian Bearman 2020-09-22 17:52 ` Nick Desaulniers
Reply instructions: You may reply publicly to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --in-reply-to=20200630191931.GA884155@elver.google.com \ --to=elver@google.com \ --cc=clang-built-linux@googlegroups.com \ --cc=gregkh@linuxfoundation.org \ --cc=keescook@chromium.org \ --cc=kernel-hardening@lists.openwall.com \ --cc=linux-arch@vger.kernel.org \ --cc=linux-arm-kernel@lists.infradead.org \ --cc=linux-kbuild@vger.kernel.org \ --cc=linux-kernel@vger.kernel.org \ --cc=linux-pci@vger.kernel.org \ --cc=masahiroy@kernel.org \ --cc=ndesaulniers@google.com \ --cc=paulmck@kernel.org \ --cc=peterz@infradead.org \ --cc=samitolvanen@google.com \ --cc=will@kernel.org \ --cc=x86@kernel.org \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: linkBe sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes, see mirroring instructions on how to clone and mirror all data and code used by this external index.