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2018-04-02Merge branch 'x86-build-for-linus' of ↵Linus Torvalds1-2/+5
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 build updates from Ingo Molnar: "The biggest change is the forcing of asm-goto support on x86, which effectively increases the GCC minimum supported version to gcc-4.5 (on x86)" * 'x86-build-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/build: Don't pass in -D__KERNEL__ multiple times x86: Remove FAST_FEATURE_TESTS x86: Force asm-goto x86/build: Drop superfluous ALIGN from the linker script
2018-03-31x86/build: Don't pass in -D__KERNEL__ multiple timesCao jin1-2/+1
Some .<target>.cmd files under arch/x86 are showing two instances of -D__KERNEL__, like arch/x86/boot/ and arch/x86/realmode/rm/. __KERNEL__ is already defined in KBUILD_CPPFLAGS in the top Makefile, so it can be dropped safely. Signed-off-by: Cao jin <caoj.fnst@cn.fujitsu.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Masahiro Yamada <yamada.masahiro@socionext.com> Cc: Michal Marek <michal.lkml@markovi.net> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kbuild@vger.kernel.org Link: http://lkml.kernel.org/r/20180316084944.3997-1-caoj.fnst@cn.fujitsu.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-03-20x86: Force asm-gotoPeter Zijlstra1-0/+4
We want to start using asm-goto to guarantee the absence of dynamic branches (and thus speculation). A primary prerequisite for this is of course that the compiler supports asm-goto. This effecively lifts the minimum GCC version to build an x86 kernel to gcc-4.5. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: torvalds@linux-foundation.org Link: https://lkml.kernel.org/r/20180319201327.GJ4043@hirez.programming.kicks-ass.net
2018-03-20x86/build/64: Force the linker to use 2MB page sizeH.J. Lu1-0/+9
Binutils 2.31 will enable -z separate-code by default for x86 to avoid mixing code pages with data to improve cache performance as well as security. To reduce x86-64 executable and shared object sizes, the maximum page size is reduced from 2MB to 4KB. But x86-64 kernel must be aligned to 2MB. Pass -z max-page-size=0x200000 to linker to force 2MB page size regardless of the default page size used by linker. Tested with Linux kernel 4.15.6 on x86-64. Signed-off-by: H.J. Lu <hjl.tools@gmail.com> Cc: Andy Shevchenko <andy.shevchenko@gmail.com> Cc: Eric Biederman <ebiederm@xmission.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Juergen Gross <jgross@suse.com> Cc: Kees Cook <keescook@chromium.org> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/CAMe9rOp4_%3D_8twdpTyAP2DhONOCeaTOsniJLoppzhoNptL8xzA@mail.gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-02-21objtool, retpolines: Integrate objtool with retpoline support more closelyPeter Zijlstra1-7/+3
Disable retpoline validation in objtool if your compiler sucks, and otherwise select the validation stuff for CONFIG_RETPOLINE=y (most builds would already have it set due to ORC). Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Thomas Gleixner <tglx@linutronix.de> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: David Woodhouse <dwmw2@infradead.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-02-20x86/retpoline: Support retpoline builds with ClangDavid Woodhouse1-1/+4
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: arjan.van.de.ven@intel.com Cc: bp@alien8.de Cc: dave.hansen@intel.com Cc: jmattson@google.com Cc: karahmed@amazon.de Cc: kvm@vger.kernel.org Cc: pbonzini@redhat.com Cc: rkrcmar@redhat.com Link: http://lkml.kernel.org/r/1519037457-7643-5-git-send-email-dwmw@amazon.co.uk Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-01-14Merge branch 'x86-pti-for-linus' of ↵Linus Torvalds1-2/+0
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 fixlet from Thomas Gleixner. Remove a warning about lack of compiler support for retpoline that most people can't do anything about, so it just annoys them needlessly. * 'x86-pti-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/retpoline: Remove compile time warning
2018-01-14x86/retpoline: Remove compile time warningThomas Gleixner1-2/+0
Remove the compile time warning when CONFIG_RETPOLINE=y and the compiler does not have retpoline support. Linus rationale for this is: It's wrong because it will just make people turn off RETPOLINE, and the asm updates - and return stack clearing - that are independent of the compiler are likely the most important parts because they are likely the ones easiest to target. And it's annoying because most people won't be able to do anything about it. The number of people building their own compiler? Very small. So if their distro hasn't got a compiler yet (and pretty much nobody does), the warning is just annoying crap. It is already properly reported as part of the sysfs interface. The compile-time warning only encourages bad things. Fixes: 76b043848fd2 ("x86/retpoline: Add initial retpoline support") Requested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: David Woodhouse <dwmw@amazon.co.uk> Cc: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: gnomes@lxorguk.ukuu.org.uk Cc: Rik van Riel <riel@redhat.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: thomas.lendacky@amd.com Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Jiri Kosina <jikos@kernel.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Kees Cook <keescook@google.com> Cc: Tim Chen <tim.c.chen@linux.intel.com> Cc: Greg Kroah-Hartman <gregkh@linux-foundation.org> Link: https://lkml.kernel.org/r/CA+55aFzWgquv4i6Mab6bASqYXg3ErV3XDFEYf=GEcCDQg5uAtw@mail.gmail.com
2018-01-14Merge branch 'x86-pti-for-linus' of ↵Linus Torvalds1-0/+10
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 pti updates from Thomas Gleixner: "This contains: - a PTI bugfix to avoid setting reserved CR3 bits when PCID is disabled. This seems to cause issues on a virtual machine at least and is incorrect according to the AMD manual. - a PTI bugfix which disables the perf BTS facility if PTI is enabled. The BTS AUX buffer is not globally visible and causes the CPU to fault when the mapping disappears on switching CR3 to user space. A full fix which restores BTS on PTI is non trivial and will be worked on. - PTI bugfixes for EFI and trusted boot which make sure that the user space visible page table entries have the NX bit cleared - removal of dead code in the PTI pagetable setup functions - add PTI documentation - add a selftest for vsyscall to verify that the kernel actually implements what it advertises. - a sysfs interface to expose vulnerability and mitigation information so there is a coherent way for users to retrieve the status. - the initial spectre_v2 mitigations, aka retpoline: + The necessary ASM thunk and compiler support + The ASM variants of retpoline and the conversion of affected ASM code + Make LFENCE serializing on AMD so it can be used as speculation trap + The RSB fill after vmexit - initial objtool support for retpoline As I said in the status mail this is the most of the set of patches which should go into 4.15 except two straight forward patches still on hold: - the retpoline add on of LFENCE which waits for ACKs - the RSB fill after context switch Both should be ready to go early next week and with that we'll have covered the major holes of spectre_v2 and go back to normality" * 'x86-pti-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (28 commits) x86,perf: Disable intel_bts when PTI security/Kconfig: Correct the Documentation reference for PTI x86/pti: Fix !PCID and sanitize defines selftests/x86: Add test_vsyscall x86/retpoline: Fill return stack buffer on vmexit x86/retpoline/irq32: Convert assembler indirect jumps x86/retpoline/checksum32: Convert assembler indirect jumps x86/retpoline/xen: Convert Xen hypercall indirect jumps x86/retpoline/hyperv: Convert assembler indirect jumps x86/retpoline/ftrace: Convert ftrace assembler indirect jumps x86/retpoline/entry: Convert entry assembler indirect jumps x86/retpoline/crypto: Convert crypto assembler indirect jumps x86/spectre: Add boot time option to select Spectre v2 mitigation x86/retpoline: Add initial retpoline support objtool: Allow alternatives to be ignored objtool: Detect jumps to retpoline thunks x86/pti: Make unpoison of pgd for trusted boot work for real x86/alternatives: Fix optimize_nops() checking sysfs/cpu: Fix typos in vulnerability documentation x86/cpu/AMD: Use LFENCE_RDTSC in preference to MFENCE_RDTSC ...
2018-01-12x86/retpoline: Add initial retpoline supportDavid Woodhouse1-0/+10
Enable the use of -mindirect-branch=thunk-extern in newer GCC, and provide the corresponding thunks. Provide assembler macros for invoking the thunks in the same way that GCC does, from native and inline assembler. This adds X86_FEATURE_RETPOLINE and sets it by default on all CPUs. In some circumstances, IBRS microcode features may be used instead, and the retpoline can be disabled. On AMD CPUs if lfence is serialising, the retpoline can be dramatically simplified to a simple "lfence; jmp *\reg". A future patch, after it has been verified that lfence really is serialising in all circumstances, can enable this by setting the X86_FEATURE_RETPOLINE_AMD feature bit in addition to X86_FEATURE_RETPOLINE. Do not align the retpoline in the altinstr section, because there is no guarantee that it stays aligned when it's copied over the oldinstr during alternative patching. [ Andi Kleen: Rename the macros, add CONFIG_RETPOLINE option, export thunks] [ tglx: Put actual function CALL/JMP in front of the macros, convert to symbolic labels ] [ dwmw2: Convert back to numeric labels, merge objtool fixes ] Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Arjan van de Ven <arjan@linux.intel.com> Acked-by: Ingo Molnar <mingo@kernel.org> Cc: gnomes@lxorguk.ukuu.org.uk Cc: Rik van Riel <riel@redhat.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: thomas.lendacky@amd.com Cc: Peter Zijlstra <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Jiri Kosina <jikos@kernel.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Kees Cook <keescook@google.com> Cc: Tim Chen <tim.c.chen@linux.intel.com> Cc: Greg Kroah-Hartman <gregkh@linux-foundation.org> Cc: Paul Turner <pjt@google.com> Link: https://lkml.kernel.org/r/1515707194-20531-4-git-send-email-dwmw@amazon.co.uk
2017-11-15kmemcheck: remove annotationsLevin, Alexander (Sasha Levin)1-5/+0
Patch series "kmemcheck: kill kmemcheck", v2. As discussed at LSF/MM, kill kmemcheck. KASan is a replacement that is able to work without the limitation of kmemcheck (single CPU, slow). KASan is already upstream. We are also not aware of any users of kmemcheck (or users who don't consider KASan as a suitable replacement). The only objection was that since KASAN wasn't supported by all GCC versions provided by distros at that time we should hold off for 2 years, and try again. Now that 2 years have passed, and all distros provide gcc that supports KASAN, kill kmemcheck again for the very same reasons. This patch (of 4): Remove kmemcheck annotations, and calls to kmemcheck from the kernel. [alexander.levin@verizon.com: correctly remove kmemcheck call from dma_map_sg_attrs] Link: http://lkml.kernel.org/r/20171012192151.26531-1-alexander.levin@verizon.com Link: http://lkml.kernel.org/r/20171007030159.22241-2-alexander.levin@verizon.com Signed-off-by: Sasha Levin <alexander.levin@verizon.com> Cc: Alexander Potapenko <glider@google.com> Cc: Eric W. Biederman <ebiederm@xmission.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Pekka Enberg <penberg@kernel.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Tim Hansen <devtimhansen@gmail.com> Cc: Vegard Nossum <vegardno@ifi.uio.no> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-11-02License cleanup: add SPDX GPL-2.0 license identifier to files with no licenseGreg Kroah-Hartman1-0/+1
Many source files in the tree are missing licensing information, which makes it harder for compliance tools to determine the correct license. By default all files without license information are under the default license of the kernel, which is GPL version 2. Update the files which contain no license information with the 'GPL-2.0' SPDX license identifier. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. How this work was done: Patches were generated and checked against linux-4.14-rc6 for a subset of the use cases: - file had no licensing information it it. - file was a */uapi/* one with no licensing information in it, - file was a */uapi/* one with existing licensing information, Further patches will be generated in subsequent months to fix up cases where non-standard license headers were used, and references to license had to be inferred by heuristics based on keywords. The analysis to determine which SPDX License Identifier to be applied to a file was done in a spreadsheet of side by side results from of the output of two independent scanners (ScanCode & Windriver) producing SPDX tag:value files created by Philippe Ombredanne. Philippe prepared the base worksheet, and did an initial spot review of a few 1000 files. The 4.13 kernel was the starting point of the analysis with 60,537 files assessed. Kate Stewart did a file by file comparison of the scanner results in the spreadsheet to determine which SPDX license identifier(s) to be applied to the file. She confirmed any determination that was not immediately clear with lawyers working with the Linux Foundation. Criteria used to select files for SPDX license identifier tagging was: - Files considered eligible had to be source code files. - Make and config files were included as candidates if they contained >5 lines of source - File already had some variant of a license header in it (even if <5 lines). All documentation files were explicitly excluded. The following heuristics were used to determine which SPDX license identifiers to apply. - when both scanners couldn't find any license traces, file was considered to have no license information in it, and the top level COPYING file license applied. For non */uapi/* files that summary was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 11139 and resulted in the first patch in this series. If that file was a */uapi/* path one, it was "GPL-2.0 WITH Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 WITH Linux-syscall-note 930 and resulted in the second patch in this series. - if a file had some form of licensing information in it, and was one of the */uapi/* ones, it was denoted with the Linux-syscall-note if any GPL family license was found in the file or had no licensing in it (per prior point). Results summary: SPDX license identifier # files ---------------------------------------------------|------ GPL-2.0 WITH Linux-syscall-note 270 GPL-2.0+ WITH Linux-syscall-note 169 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17 LGPL-2.1+ WITH Linux-syscall-note 15 GPL-1.0+ WITH Linux-syscall-note 14 ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5 LGPL-2.0+ WITH Linux-syscall-note 4 LGPL-2.1 WITH Linux-syscall-note 3 ((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3 ((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1 and that resulted in the third patch in this series. - when the two scanners agreed on the detected license(s), that became the concluded license(s). - when there was disagreement between the two scanners (one detected a license but the other didn't, or they both detected different licenses) a manual inspection of the file occurred. - In most cases a manual inspection of the information in the file resulted in a clear resolution of the license that should apply (and which scanner probably needed to revisit its heuristics). - When it was not immediately clear, the license identifier was confirmed with lawyers working with the Linux Foundation. - If there was any question as to the appropriate license identifier, the file was flagged for further research and to be revisited later in time. In total, over 70 hours of logged manual review was done on the spreadsheet to determine the SPDX license identifiers to apply to the source files by Kate, Philippe, Thomas and, in some cases, confirmation by lawyers working with the Linux Foundation. Kate also obtained a third independent scan of the 4.13 code base from FOSSology, and compared selected files where the other two scanners disagreed against that SPDX file, to see if there was new insights. The Windriver scanner is based on an older version of FOSSology in part, so they are related. Thomas did random spot checks in about 500 files from the spreadsheets for the uapi headers and agreed with SPDX license identifier in the files he inspected. For the non-uapi files Thomas did random spot checks in about 15000 files. In initial set of patches against 4.14-rc6, 3 files were found to have copy/paste license identifier errors, and have been fixed to reflect the correct identifier. Additionally Philippe spent 10 hours this week doing a detailed manual inspection and review of the 12,461 patched files from the initial patch version early this week with: - a full scancode scan run, collecting the matched texts, detected license ids and scores - reviewing anything where there was a license detected (about 500+ files) to ensure that the applied SPDX license was correct - reviewing anything where there was no detection but the patch license was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied SPDX license was correct This produced a worksheet with 20 files needing minor correction. This worksheet was then exported into 3 different .csv files for the different types of files to be modified. These .csv files were then reviewed by Greg. Thomas wrote a script to parse the csv files and add the proper SPDX tag to the file, in the format that the file expected. This script was further refined by Greg based on the output to detect more types of files automatically and to distinguish between header and source .c files (which need different comment types.) Finally Greg ran the script using the .csv files to generate the patches. Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-08-21x86/build: Use cc-option to validate stack alignment parameterMatthias Kaehlcke1-3/+3
With the following commit: 8f91869766c0 ("x86/build: Fix stack alignment for CLang") cc-option is only used to determine the name of the stack alignment option supported by the compiler, but not to verify that the actual parameter <option>=N is valid in combination with the other CFLAGS. This causes problems (as reported by the kbuild robot) with older GCC versions which only support stack alignment on a boundary of 16 bytes or higher. Also use (__)cc_option to add the stack alignment option to CFLAGS to make sure only valid options are added. Reported-by: kbuild test robot <fengguang.wu@intel.com> Signed-off-by: Matthias Kaehlcke <mka@chromium.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Bernhard.Rosenkranzer@linaro.org Cc: Greg Hackmann <ghackmann@google.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Masahiro Yamada <yamada.masahiro@socionext.com> Cc: Michael Davidson <md@google.com> Cc: Nick Desaulniers <ndesaulniers@google.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephen Hines <srhines@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: dianders@chromium.org Fixes: 8f91869766c0 ("x86/build: Fix stack alignment for CLang") Link: http://lkml.kernel.org/r/20170817182047.176752-1-mka@chromium.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-08-17x86/build: Fix stack alignment for CLangMatthias Kaehlcke1-6/+8
Commit: d77698df39a5 ("x86/build: Specify stack alignment for clang") intended to use the same stack alignment for clang as with gcc. The two compilers use different options to configure the stack alignment (gcc: -mpreferred-stack-boundary=n, clang: -mstack-alignment=n). The above commit assumes that the clang option uses the same parameter type as gcc, i.e. that the alignment is specified as 2^n. However clang interprets the value of this option literally to use an alignment of n, in consequence the stack remains misaligned. Change the values used with -mstack-alignment to be the actual alignment instead of a power of two. cc-option isn't used here with the typical pattern of KBUILD_CFLAGS += $(call cc-option ...). The reason is that older gcc versions don't support the -mpreferred-stack-boundary option, since cc-option doesn't verify whether the alternative option is valid it would incorrectly select the clang option -mstack-alignment.. Signed-off-by: Matthias Kaehlcke <mka@chromium.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Bernhard.Rosenkranzer@linaro.org Cc: Greg Hackmann <ghackmann@google.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Masahiro Yamada <yamada.masahiro@socionext.com> Cc: Michael Davidson <md@google.com> Cc: Nick Desaulniers <ndesaulniers@google.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephen Hines <srhines@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: dianders@chromium.org Link: http://lkml.kernel.org/r/20170817004740.170588-1-mka@chromium.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-08-10x86/build: Drop unused mflags-yCao jin1-3/+0
Subarchitecture support (mflags-y) was removed from x86 in this commit: 6bda2c8b32fe ("x86: remove subarchitecture support") So drop the mflags-y usage from the Makefile. Signed-off-by: Cao jin <caoj.fnst@cn.fujitsu.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1502105384-23214-1-git-send-email-caoj.fnst@cn.fujitsu.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-07-07Merge tag 'kbuild-v4.13' of ↵Linus Torvalds1-8/+25
git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild Pull Kbuild updates from Masahiro Yamada: - Clean up Makefiles and scripts - Improve clang support - Remove unneeded genhdr-y syntax - Remove unneeded cc-option-align macro - Introduce __cc-option macro and use it to fix x86 boot code compiler flags * tag 'kbuild-v4.13' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: kbuild: improve comments on KBUILD_SRC x86/build: Specify stack alignment for clang x86/build: Use __cc-option for boot code compiler options kbuild: Add __cc-option macro kbuild: remove cc-option-align kbuild: replace genhdr-y with generated-y kbuild: clang: Disable 'address-of-packed-member' warning kbuild: remove duplicated arch/*/include/generated/uapi include path kbuild: speed up checksyscalls.sh kbuild: simplify silent build (-s) detection
2017-06-25x86/build: Specify stack alignment for clangMatthias Kaehlcke1-5/+21
For gcc stack alignment is configured with -mpreferred-stack-boundary=N, clang has the option -mstack-alignment=N for that purpose. Use the same alignment as with gcc. If the alignment is not specified clang assumes an alignment of 16 bytes, as required by the standard ABI. However as mentioned in d9b0cde91c60 ("x86-64, gcc: Use -mpreferred-stack-boundary=3 if supported") the standard kernel entry on x86-64 leaves the stack on an 8-byte boundary, as a consequence clang will keep the stack misaligned. Signed-off-by: Matthias Kaehlcke <mka@chromium.org> Acked-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2017-06-25x86/build: Use __cc-option for boot code compiler optionsMatthias Kaehlcke1-4/+5
cc-option is used to enable compiler options for the boot code if they are available. The macro uses KBUILD_CFLAGS and KBUILD_CPPFLAGS for the check, however these flags aren't used to build the boot code, in consequence cc-option can yield wrong results. For example -mpreferred-stack-boundary=2 is never set with a 64-bit compiler, since the setting is only valid for 16 and 32-bit binaries. This is also the case for 32-bit kernel builds, because the option -m32 is added to KBUILD_CFLAGS after the assignment of REALMODE_CFLAGS. Use __cc-option instead of cc-option for the boot mode options. The macro receives the compiler options as parameter instead of using KBUILD_C*FLAGS, for the boot code we pass REALMODE_CFLAGS. Also use separate statements for the __cc-option checks instead of performing them in the initial assignment of REALMODE_CFLAGS since the variable is an input of the macro. Signed-off-by: Matthias Kaehlcke <mka@chromium.org> Acked-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2017-06-14x86/mce: Merge mce_amd_inj into mce-injectBorislav Petkov1-2/+0
Reuse mce_amd_inj's debugfs interface so that mce-inject can benefit from it too. The old functionality is still preserved under CONFIG_X86_MCELOG_LEGACY. Tested-by: Yazen Ghannam <yazen.ghannam@amd.com> Signed-off-by: Borislav Petkov <bp@suse.de> Acked-by: Yazen Ghannam <yazen.ghannam@amd.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tony Luck <tony.luck@intel.com> Link: http://lkml.kernel.org/r/20170613162835.30750-4-bp@alien8.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-05-24x86/build: Permit building with old make versionsJan Kiszka1-1/+1
At least Make 3.82 dislikes the tab in front of the $(warning) function: arch/x86/Makefile:162: *** recipe commences before first target. Stop. Let's be gentle. Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com> Acked-by: Thomas Gleixner <tglx@linutronix.de> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/1944fcd8-e3df-d1f7-c0e4-60aeb1917a24@siemens.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-05-09x86/build: Don't add -maccumulate-outgoing-args w/o compiler supportNick Desaulniers1-1/+2
Clang does not support this machine dependent option. Older versions of GCC (pre 3.0) may not support this option, added in 2000, but it's unlikely they can still compile a working kernel. Signed-off-by: Nick Desaulniers <nick.desaulniers@gmail.com> Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20170509032946.20444-1-nick.desaulniers@gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-05-01Merge branch 'x86-build-for-linus' of ↵Linus Torvalds1-2/+2
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 build update from Ingo Molnar: "A single CLang support related fix" * 'x86-build-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/kbuild: Use cc-option to enable -falign-{jumps/loops}
2017-04-19x86/build: convert function graph '-Os' error to warningJosh Poimboeuf1-0/+8
For pre-4.6.0 versions of GCC, which don't have '-mfentry', the '-maccumulate-outgoing-args' option is required for function graph tracing in order to avoid GCC bug 42109. However, GCC ignores '-maccumulate-outgoing-args' when '-Os' is also set. Currently we force a build error to prevent that scenario, but that breaks randconfigs. So change the error to a warning which also disables CONFIG_CC_OPTIMIZE_FOR_SIZE. Reported-by: Andi Kleen <andi@firstfloor.org> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: kbuild test robot <fengguang.wu@intel.com> Cc: kbuild-all@01.org Link: http://lkml.kernel.org/r/20170418214429.o7fbwbmf4nqosezy@treble Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-04-17x86/kbuild: Use cc-option to enable -falign-{jumps/loops}Matthias Kaehlcke1-2/+2
clang currently does not support these optimizations, only enable them when they are available. Signed-off-by: Matthias Kaehlcke <mka@chromium.org> Cc: Greg Hackmann <ghackmann@google.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Masahiro Yamada <yamada.masahiro@socionext.com> Cc: Michael Davidson <md@google.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: grundler@chromium.org Link: http://lkml.kernel.org/r/20170413172609.118122-1-mka@chromium.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-03-30x86/build: Mostly disable '-maccumulate-outgoing-args'Josh Poimboeuf1-4/+31
The GCC '-maccumulate-outgoing-args' flag is enabled for most configs, mostly because of issues which are no longer relevant. For most configs, and with most recent versions of GCC, it's no longer needed. Clarify which cases need it, and only enable it for those cases. Also produce a compile-time error for the ftrace graph + mcount + '-Os' case, which will otherwise cause runtime failures. The main benefit of '-maccumulate-outgoing-args' is that it prevents an ugly prologue for functions which have aligned stacks. But removing the option also has some benefits: more readable argument saves, smaller text size, and (presumably) slightly improved performance. Here are the object size savings for 32-bit and 64-bit defconfig kernels: text data bss dec hex filename 10006710 3543328 1773568 15323606 e9d1d6 vmlinux.x86-32.before 9706358 3547424 1773568 15027350 e54c96 vmlinux.x86-32.after text data bss dec hex filename 10652105 4537576 843776 16033457 f4a6b1 vmlinux.x86-64.before 10639629 4537576 843776 16020981 f475f5 vmlinux.x86-64.after That comes out to a 3% text size improvement on x86-32 and a 0.1% text size improvement on x86-64. Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Andrew Lutomirski <luto@kernel.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Pavel Machek <pavel@ucw.cz> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20170316193133.zrj6gug53766m6nn@treble Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-09-21lib/raid6: Add AVX512 optimized gen_syndrome functionsGayatri Kammela1-2/+3
Optimize RAID6 gen_syndrom functions to take advantage of the 512-bit ZMM integer instructions introduced in AVX512. AVX512 optimized gen_syndrom functions, which is simply based on avx2.c written by Yuanhan Liu and sse2.c written by hpa. The patch was tested and benchmarked before submission on a hardware that has AVX512 flags to support such instructions Cc: H. Peter Anvin <hpa@zytor.com> Cc: Jim Kukunas <james.t.kukunas@linux.intel.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Signed-off-by: Megha Dey <megha.dey@linux.intel.com> Signed-off-by: Gayatri Kammela <gayatri.kammela@intel.com> Reviewed-by: Fenghua Yu <fenghua.yu@intel.com> Signed-off-by: Shaohua Li <shli@fb.com>
2016-07-26kbuild: abort build on bad stack protector flagKees Cook1-8/+0
Before, the stack protector flag was sanity checked before .config had been reprocessed. This meant the build couldn't be aborted early, and only a warning could be emitted followed later by the compiler blowing up with an unknown flag. This has caused a lot of confusion over time, so this splits the flag selection from sanity checking and performs the sanity checking after the make has been restarted from a reprocessed .config, so builds can be aborted as early as possible now. Additionally moves the x86-specific sanity check to the same location, since it suffered from the same warn-then-wait-for-compiler-failure problem. Link: http://lkml.kernel.org/r/20160712223043.GA11664@www.outflux.net Signed-off-by: Kees Cook <keescook@chromium.org> Cc: Michal Marek <mmarek@suse.com> Cc: Ingo Molnar <mingo@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-04-22x86/init: Rename EBDA code fileLuis R. Rodriguez1-1/+1
This makes it clearer what this is. Signed-off-by: Luis R. Rodriguez <mcgrof@kernel.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: andrew.cooper3@citrix.com Cc: andriy.shevchenko@linux.intel.com Cc: bigeasy@linutronix.de Cc: boris.ostrovsky@oracle.com Cc: david.vrabel@citrix.com Cc: ffainelli@freebox.fr Cc: george.dunlap@citrix.com Cc: glin@suse.com Cc: jgross@suse.com Cc: jlee@suse.com Cc: josh@joshtriplett.org Cc: julien.grall@linaro.org Cc: konrad.wilk@oracle.com Cc: kozerkov@parallels.com Cc: lenb@kernel.org Cc: lguest@lists.ozlabs.org Cc: linux-acpi@vger.kernel.org Cc: lv.zheng@intel.com Cc: matt@codeblueprint.co.uk Cc: mbizon@freebox.fr Cc: rjw@rjwysocki.net Cc: robert.moore@intel.com Cc: rusty@rustcorp.com.au Cc: tiwai@suse.de Cc: toshi.kani@hp.com Cc: xen-devel@lists.xensource.com Link: http://lkml.kernel.org/r/1460592286-300-14-git-send-email-mcgrof@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-04-22x86/rtc: Replace paravirt rtc check with platform legacy quirkLuis R. Rodriguez1-0/+1
We have 4 types of x86 platforms that disable RTC: * Intel MID * Lguest - uses paravirt * Xen dom-U - uses paravirt * x86 on legacy systems annotated with an ACPI legacy flag We can consolidate all of these into a platform specific legacy quirk set early in boot through i386_start_kernel() and through x86_64_start_reservations(). This deals with the RTC quirks which we can rely on through the hardware subarch, the ACPI check can be dealt with separately. For Xen things are bit more complex given that the @X86_SUBARCH_XEN x86_hardware_subarch is shared on for Xen which uses the PV path for both domU and dom0. Since the semantics for differentiating between the two are Xen specific we provide a platform helper to help override default legacy features -- x86_platform.set_legacy_features(). Use of this helper is highly discouraged, its only purpose should be to account for the lack of semantics available within your given x86_hardware_subarch. As per 0-day, this bumps the vmlinux size using i386-tinyconfig as follows: TOTAL TEXT init.text x86_early_init_platform_quirks() +70 +62 +62 +43 Only 8 bytes overhead total, as the main increase in size is all removed via __init. Suggested-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Luis R. Rodriguez <mcgrof@kernel.org> Reviewed-by: Juergen Gross <jgross@suse.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: andrew.cooper3@citrix.com Cc: andriy.shevchenko@linux.intel.com Cc: bigeasy@linutronix.de Cc: boris.ostrovsky@oracle.com Cc: david.vrabel@citrix.com Cc: ffainelli@freebox.fr Cc: george.dunlap@citrix.com Cc: glin@suse.com Cc: jlee@suse.com Cc: josh@joshtriplett.org Cc: julien.grall@linaro.org Cc: konrad.wilk@oracle.com Cc: kozerkov@parallels.com Cc: lenb@kernel.org Cc: lguest@lists.ozlabs.org Cc: linux-acpi@vger.kernel.org Cc: lv.zheng@intel.com Cc: matt@codeblueprint.co.uk Cc: mbizon@freebox.fr Cc: rjw@rjwysocki.net Cc: robert.moore@intel.com Cc: rusty@rustcorp.com.au Cc: tiwai@suse.de Cc: toshi.kani@hp.com Cc: xen-devel@lists.xensource.com Link: http://lkml.kernel.org/r/1460592286-300-5-git-send-email-mcgrof@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-11-04Merge branch 'linus' of ↵Linus Torvalds1-2/+4
git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 Pull crypto update from Herbert Xu: "API: - Add support for cipher output IVs in testmgr - Add missing crypto_ahash_blocksize helper - Mark authenc and des ciphers as not allowed under FIPS. Algorithms: - Add CRC support to 842 compression - Add keywrap algorithm - A number of changes to the akcipher interface: + Separate functions for setting public/private keys. + Use SG lists. Drivers: - Add Intel SHA Extension optimised SHA1 and SHA256 - Use dma_map_sg instead of custom functions in crypto drivers - Add support for STM32 RNG - Add support for ST RNG - Add Device Tree support to exynos RNG driver - Add support for mxs-dcp crypto device on MX6SL - Add xts(aes) support to caam - Add ctr(aes) and xts(aes) support to qat - A large set of fixes from Russell King for the marvell/cesa driver" * 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6: (115 commits) crypto: asymmetric_keys - Fix unaligned access in x509_get_sig_params() crypto: akcipher - Don't #include crypto/public_key.h as the contents aren't used hwrng: exynos - Add Device Tree support hwrng: exynos - Fix missing configuration after suspend to RAM hwrng: exynos - Add timeout for waiting on init done dt-bindings: rng: Describe Exynos4 PRNG bindings crypto: marvell/cesa - use __le32 for hardware descriptors crypto: marvell/cesa - fix missing cpu_to_le32() in mv_cesa_dma_add_op() crypto: marvell/cesa - use memcpy_fromio()/memcpy_toio() crypto: marvell/cesa - use gfp_t for gfp flags crypto: marvell/cesa - use dma_addr_t for cur_dma crypto: marvell/cesa - use readl_relaxed()/writel_relaxed() crypto: caam - fix indentation of close braces crypto: caam - only export the state we really need to export crypto: caam - fix non-block aligned hash calculation crypto: caam - avoid needlessly saving and restoring caam_hash_ctx crypto: caam - print errno code when hash registration fails crypto: marvell/cesa - fix memory leak crypto: marvell/cesa - fix first-fragment handling in mv_cesa_ahash_dma_last_req() crypto: marvell/cesa - rearrange handling for sw padded hashes ...
2015-10-09x86/asm: Re-add parts of the manual CFI infrastructureAndy Lutomirski1-2/+8
Commit: 131484c8da97 ("x86/debug: Remove perpetually broken, unmaintainable dwarf annotations") removed all the manual DWARF annotations outside the vDSO. It also removed the macros we used for the manual annotations. Re-add these macros so that we can clean up the vDSO annotations. Signed-off-by: Andy Lutomirski <luto@kernel.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Link: http://lkml.kernel.org/r/4c70bb98a8b773c8ccfaabf6745e569ff43e7f65.1444091584.git.luto@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-09-21crypto: x86/sha - Add build support for Intel SHA Extensions optimized SHA1 ↵tim1-2/+4
and SHA256 This patch provides the configuration and build support to include and build the optimized SHA1 and SHA256 update transforms for the kernel's crypto library. Originally-by: Chandramouli Narayanan <mouli_7982@yahoo.com> Signed-off-by: Tim Chen <tim.c.chen@linux.intel.com> Acked-by: David S. Miller <davem@davemloft.net> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2015-09-01Merge branch 'x86-asm-for-linus' of ↵Linus Torvalds1-3/+10
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 asm changes from Ingo Molnar: "The biggest changes in this cycle were: - Revamp, simplify (and in some cases fix) Time Stamp Counter (TSC) primitives. (Andy Lutomirski) - Add new, comprehensible entry and exit handlers written in C. (Andy Lutomirski) - vm86 mode cleanups and fixes. (Brian Gerst) - 32-bit compat code cleanups. (Brian Gerst) The amount of simplification in low level assembly code is already palpable: arch/x86/entry/entry_32.S | 130 +---- arch/x86/entry/entry_64.S | 197 ++----- but more simplifications are planned. There's also the usual laudry mix of low level changes - see the changelog for details" * 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (83 commits) x86/asm: Drop repeated macro of X86_EFLAGS_AC definition x86/asm/msr: Make wrmsrl() a function x86/asm/delay: Introduce an MWAITX-based delay with a configurable timer x86/asm: Add MONITORX/MWAITX instruction support x86/traps: Weaken context tracking entry assertions x86/asm/tsc: Add rdtscll() merge helper selftests/x86: Add syscall_nt selftest selftests/x86: Disable sigreturn_64 x86/vdso: Emit a GNU hash x86/entry: Remove do_notify_resume(), syscall_trace_leave(), and their TIF masks x86/entry/32: Migrate to C exit path x86/entry/32: Remove 32-bit syscall audit optimizations x86/vm86: Rename vm86->v86flags and v86mask x86/vm86: Rename vm86->vm86_info to user_vm86 x86/vm86: Clean up vm86.h includes x86/vm86: Move the vm86 IRQ definitions to vm86.h x86/vm86: Use the normal pt_regs area for vm86 x86/vm86: Eliminate 'struct kernel_vm86_struct' x86/vm86: Move fields from 'struct kernel_vm86_struct' to 'struct vm86' x86/vm86: Move vm86 fields out of 'thread_struct' ...
2015-08-13x86/ras: Move AMD MCE injector to arch/x86/ras/Borislav Petkov1-0/+2
This is an x86-specific module and would benefit from being closer to the arch code. Move it there. Update copyright while at it. Signed-off-by: Borislav Petkov <bp@suse.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tony Luck <tony.luck@intel.com> Link: http://lkml.kernel.org/r/1439396985-12812-14-git-send-email-bp@alien8.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-07-22x86/build: Fix detection of GCC -mpreferred-stack-boundary supportAndy Lutomirski1-3/+10
As per: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53383 GCC only allows -mpreferred-stack-boundary=3 on x86_64 if -mno-sse is set. That means that cc-option will not detect -mpreferred-stack-boundary=3 support, because we test for it before setting -mno-sse. Fix it by reordering the Makefile bits. Compile-tested only. This should help avoid code generation issues such as the one that was worked around in: b96fecbfa8c8 ("x86/fpu: Fix boot crash in the early FPU code") I'm a bit concerned that we could still have problems on older GCC versions given that our asm code does not respect GCC's idea of the ABI-required stack alignment. Signed-off-by: Andy Lutomirski <luto@kernel.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Jan Kara <jack@suse.cz> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/f5297c192969adfa0d28b84cf8a22d59573db26d.1436126872.git.luto@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-06-04x86/asm/entry: Move the arch/x86/syscalls/ definitions to ↵Ingo Molnar1-1/+1
arch/x86/entry/syscalls/ The build time generated syscall definitions are entry code related, move them into the arch/x86/entry/ directory. Cc: Borislav Petkov <bp@alien8.de> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Brian Gerst <brgerst@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-06-03x86/asm/entry, x86/vdso: Move the vDSO code to arch/x86/entry/vdso/Ingo Molnar1-1/+1
Cc: Borislav Petkov <bp@alien8.de> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Brian Gerst <brgerst@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-06-02x86/debug: Remove perpetually broken, unmaintainable dwarf annotationsIngo Molnar1-8/+2
So the dwarf2 annotations in low level assembly code have become an increasing hindrance: unreadable, messy macros mixed into some of the most security sensitive code paths of the Linux kernel. These debug info annotations don't even buy the upstream kernel anything: dwarf driven stack unwinding has caused problems in the past so it's out of tree, and the upstream kernel only uses the much more robust framepointers based stack unwinding method. In addition to that there's a steady, slow bitrot going on with these annotations, requiring frequent fixups. There's no tooling and no functionality upstream that keeps it correct. So burn down the sick forest, allowing new, healthier growth: 27 files changed, 350 insertions(+), 1101 deletions(-) Someone who has the willingness and time to do this properly can attempt to reintroduce dwarf debuginfo in x86 assembly code plus dwarf unwinding from first principles, with the following conditions: - it should be maximally readable, and maximally low-key to 'ordinary' code reading and maintenance. - find a build time method to insert dwarf annotations automatically in the most common cases, for pop/push instructions that manipulate the stack pointer. This could be done for example via a preprocessing step that just looks for common patterns - plus special annotations for the few cases where we want to depart from the default. We have hundreds of CFI annotations, so automating most of that makes sense. - it should come with build tooling checks that ensure that CFI annotations are sensible. We've seen such efforts from the framepointer side, and there's no reason it couldn't be done on the dwarf side. Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Frédéric Weisbecker <fweisbec@gmail.com Cc: H. Peter Anvin <hpa@zytor.com> Cc: Jan Beulich <JBeulich@suse.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-05-17x86: Pack loops tightly as wellIngo Molnar1-0/+3
Packing loops tightly (-falign-loops=1) is beneficial to code size: text data bss dec filename 12566391 1617840 1089536 15273767 vmlinux.align.16-byte 12224951 1617840 1089536 14932327 vmlinux.align.1-byte 11976567 1617840 1089536 14683943 vmlinux.align.1-byte.funcs-1-byte 11903735 1617840 1089536 14611111 vmlinux.align.1-byte.funcs-1-byte.loops-1-byte Which reduces the size of the kernel by another 0.6%, so the the total combined size reduction of the alignment-packing patches is ~5.5%. The x86 decoder bandwidth and caching arguments laid out in: be6cb02779ca ("x86: Align jump targets to 1-byte boundaries") apply to loop alignment as well. Furtermore, modern CPU uarchs have a loop cache/buffer that is a L0 cache before even any uop cache, covering a few dozen most recently executed instructions. This loop cache generally does not have the 16-byte alignment restrictions of the uop cache. Now loop alignment can still be beneficial if: - a loop is cache-hot and its surroundings are not. - if the loop is so cache hot that the instruction flow becomes x86 decoder bandwidth limited But loop alignment is harmful if: - a loop is cache-cold - a loop's surroundings are cache-hot as well - two cache-hot loops are close to each other - if the loop fits into the loop cache - if the code flow is not decoder bandwidth limited and I'd argue that the latter five scenarios are much more common in the kernel, as our hottest loops are typically: - pointer chasing: this should fit into the loop cache in most cases and is typically data cache and address generation limited - generic memory ops (memset, memcpy, etc.): these generally fit into the loop cache as well, and are likewise data cache limited. So this patch packs loop addresses tightly as well. Acked-by: Denys Vlasenko <dvlasenk@redhat.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Aswin Chandramouleeswaran <aswin@hp.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Jason Low <jason.low2@hp.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tim Chen <tim.c.chen@linux.intel.com> Link: http://lkml.kernel.org/r/20150410123017.GB19918@gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-05-15x86: Align jump targets to 1-byte boundariesIngo Molnar1-0/+3
The following NOP in a hot function caught my attention: > 5a: 66 0f 1f 44 00 00 nopw 0x0(%rax,%rax,1) That's a dead NOP that bloats the function a bit, added for the default 16-byte alignment that GCC applies for jump targets. I realize that x86 CPU manufacturers recommend 16-byte jump target alignments (it's in the Intel optimization manual), to help their relatively narrow decoder prefetch alignment and uop cache constraints, but the cost of that is very significant: text data bss dec filename 12566391 1617840 1089536 15273767 vmlinux.align.16-byte 12224951 1617840 1089536 14932327 vmlinux.align.1-byte By using 1-byte jump target alignment (i.e. no alignment at all) we get an almost 3% reduction in kernel size (!) - and a probably similar reduction in I$ footprint. Now, the usual justification for jump target alignment is the following: - modern decoders tend to have 16-byte (effective) decoder prefetch windows. (AMD documents it higher but measurements suggest the effective prefetch window on curretn uarchs is still around 16 bytes) - on Intel there's also the uop-cache with cachelines that have 16-byte granularity and limited associativity. - older x86 uarchs had a penalty for decoder fetches that crossed 16-byte boundaries. These limits are mostly gone from recent uarchs. So if a forward jump target is aligned to cacheline boundary then prefetches will start from a new prefetch-cacheline and there's higher chance for decoding in fewer steps and packing tightly. But I think that argument is flawed for typical optimized kernel code flows: forward jumps often go to 'cold' (uncommon) pieces of code, and aligning cold code to cache lines does not bring a lot of advantages (they are uncommon), while it causes collateral damage: - their alignment 'spreads out' the cache footprint, it shifts followup hot code further out - plus it slows down even 'cold' code that immediately follows 'hot' code (like in the above case), which could have benefited from the partial cacheline that comes off the end of hot code. But even in the cache-hot case the 16 byte alignment brings disadvantages: - it spreads out the cache footprint, possibly making the code fall out of the L1 I$. - On Intel CPUs, recent microarchitectures have plenty of uop cache (typically doubling every 3 years) - while the size of the L1 cache grows much less aggressively. So workloads are rarely uop cache limited. The only situation where alignment might matter are tight loops that could fit into a single 16 byte chunk - but those are pretty rare in the kernel: if they exist they tend to be pointer chasing or generic memory ops, which both tend to be cache miss (or cache allocation) intensive and are not decoder bandwidth limited. So the balance of arguments strongly favors packing kernel instructions tightly versus maximizing for decoder bandwidth: this patch changes the jump target alignment from 16 bytes to 1 byte (tightly packed, unaligned). Acked-by: Denys Vlasenko <dvlasenk@redhat.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Aswin Chandramouleeswaran <aswin@hp.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Jason Low <jason.low2@hp.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tim Chen <tim.c.chen@linux.intel.com> Link: http://lkml.kernel.org/r/20150410120846.GA17101@gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-05-08Merge branch 'linus' into x86/asm, before applying dependent patchIngo Molnar1-1/+1
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-05-06x86/asm: Use -mskip-rax-setup if supportedH.J. Lu1-0/+3
GCC 5 added a compiler option, -mskip-rax-setup, for x86-64. It skips setting up the RAX register when SSE is disabled and there are no variable arguments passed in vector registers. (According to the x86_64 ABI, %al is used as a hidden register containing the number of vector registers used). Since the kernel doesn't pass vector registers to functions with variable arguments, this option can be used to optimize the x86-64 kernel. This GCC feature was suggested by Rasmus Villemoes <linux@rasmusvillemoes.dk>. This is the corresponding kernel change using it. For kernel v3.17: text data bss dec filename 11455921 2204048 5853184 19513153 vmlinux #with -mskip-rax-setup 11480079 2204048 5853184 19537311 vmlinux For Kernel v4.0+ - custom config: text data bss dec filename 10231778 3479800 16617472 30329050 vmlinux-gcc5+-mskip-rax-setup 10268797 3547448 16621568 30437813 vmlinux Signed-off-by: H.J. Lu <hjl.tools@gmail.com> Signed-off-by: Borislav Petkov <bp@suse.de> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-04-02kbuild: use relative path more to include MakefileMasahiro Yamada1-1/+1
Prior to this commit, it was impossible to use relative path to include Makefiles from the top level Makefile because the option "--include-dir=$(srctree)" becomes effective when Make enters into sub Makefiles. To use relative path in any places, this commit moves the option above the "sub-make" target. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Signed-off-by: Michal Marek <mmarek@suse.cz>
2015-02-04x86/raid6: correctly check for assembler capabilitiesJan Beulich1-0/+1
Just like for AVX2 (which simply needs an #if -> #ifdef conversion), SSSE3 assembler support should be checked for before using it. Signed-off-by: Jan Beulich <jbeulich@suse.com> Cc: Jim Kukunas <james.t.kukunas@linux.intel.com> Acked-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: NeilBrown <neilb@suse.de>
2014-10-13Merge branch 'x86-build-for-linus' of ↵Linus Torvalds1-6/+2
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 build update from Ingo Molnar: "A single commit that simplifies the no-FPU-ops build options" * 'x86-build-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/kbuild: Eliminate duplicate command line options
2014-10-07Merge tag 'tiny/for-3.18' of ↵Linus Torvalds1-7/+0
git://git.kernel.org/pub/scm/linux/kernel/git/josh/linux Pull "tinification" patches from Josh Triplett. Work on making smaller kernels. * tag 'tiny/for-3.18' of git://git.kernel.org/pub/scm/linux/kernel/git/josh/linux: bloat-o-meter: Ignore syscall aliases SyS_ and compat_SyS_ mm: Support compiling out madvise and fadvise x86: Support compiling out human-friendly processor feature names x86: Drop support for /proc files when !CONFIG_PROC_FS x86, boot: Don't compile early_serial_console.c when !CONFIG_EARLY_PRINTK x86, boot: Don't compile aslr.c when !CONFIG_RANDOMIZE_BASE x86, boot: Use the usual -y -n mechanism for objects in vmlinux x86: Add "make tinyconfig" to configure the tiniest possible kernel x86, platform, kconfig: move kvmconfig functionality to a helper
2014-09-22Merge branches 'tiny/bloat-o-meter-no-SyS', 'tiny/more-procless', ↵Josh Triplett1-7/+0
'tiny/no-advice', 'tiny/tinyconfig' and 'tiny/x86-boot-compressed-use-yn' into tiny/next
2014-09-16x86/kbuild: Eliminate duplicate command line optionsRasmus Villemoes1-6/+2
The options -mno-mmx and -mno-sse are unconditionally added to KBUILD_CFLAGS in both branches of an ifeq and through a $(cc-option) further down. We can safely remove the first instances. In fact, since the -mno-mmx and -mno-sse options were introduced simultaneous with the other two options in the $(cc-option) [according to http://www.gnu.org/software/gcc/gcc-3.1/changes.html], and since the former were unconditionally used, one can deduce that only gcc versions knowing about all four are supported. So also eliminate the $(cc-option) wrap. Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk> Acked-by: Peter Foley <pefoley2@pefoley.com> Link: http://lkml.kernel.org/r/1410365139-24440-1-git-send-email-linux@rasmusvillemoes.dk Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-08-29kexec: purgatory: add clean-up for purgatory directoryMichael Welling1-0/+1
Without this patch the kexec-purgatory.c and purgatory.ro files are not removed after make mrproper. Signed-off-by: Michael Welling <mwelling@ieee.org> Acked-by: Vivek Goyal <vgoyal@redhat.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-08-29kexec: create a new config option CONFIG_KEXEC_FILE for new syscallVivek Goyal1-4/+1
Currently new system call kexec_file_load() and all the associated code compiles if CONFIG_KEXEC=y. But new syscall also compiles purgatory code which currently uses gcc option -mcmodel=large. This option seems to be available only gcc 4.4 onwards. Hiding new functionality behind a new config option will not break existing users of old gcc. Those who wish to enable new functionality will require new gcc. Having said that, I am trying to figure out how can I move away from using -mcmodel=large but that can take a while. I think there are other advantages of introducing this new config option. As this option will be enabled only on x86_64, other arches don't have to compile generic kexec code which will never be used. This new code selects CRYPTO=y and CRYPTO_SHA256=y. And all other arches had to do this for CONFIG_KEXEC. Now with introduction of new config option, we can remove crypto dependency from other arches. Now CONFIG_KEXEC_FILE is available only on x86_64. So whereever I had CONFIG_X86_64 defined, I got rid of that. For CONFIG_KEXEC_FILE, instead of doing select CRYPTO=y, I changed it to "depends on CRYPTO=y". This should be safer as "select" is not recursive. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Cc: Eric Biederman <ebiederm@xmission.com> Cc: H. Peter Anvin <hpa@zytor.com> Tested-by: Shaun Ruffell <sruffell@digium.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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