kernel.git/arch/x86/Makefile, branch linux-4.17.y

Merge branch 'x86-build-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2018-04-02T21:37:03Z

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

x86/build: Don't pass in -DKERNEL multiple times

2018-03-31T06:02:07Z

Some ..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 Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Masahiro Yamada Cc: Michal Marek Cc: Peter Zijlstra Cc: Thomas Gleixner 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

x86: Force asm-goto

2018-03-20T09:58:02Z

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) Signed-off-by: Thomas Gleixner Cc: torvalds@linux-foundation.org Link: https://lkml.kernel.org/r/20180319201327.GJ4043@hirez.programming.kicks-ass.net

x86/build/64: Force the linker to use 2MB page size

2018-03-20T07:03:03Z

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 Cc: Andy Shevchenko Cc: Eric Biederman Cc: H. Peter Anvin Cc: Juergen Gross Cc: Kees Cook Cc: Kirill A. Shutemov Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/CAMe9rOp4_%3D_8twdpTyAP2DhONOCeaTOsniJLoppzhoNptL8xzA@mail.gmail.com Signed-off-by: Ingo Molnar

objtool, retpolines: Integrate objtool with retpoline support more closely

2018-02-21T15:54:32Z

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) Acked-by: Thomas Gleixner Cc: Andy Lutomirski Cc: Arjan van de Ven Cc: Borislav Petkov Cc: Dan Williams Cc: Dave Hansen Cc: David Woodhouse Cc: Greg Kroah-Hartman Cc: Josh Poimboeuf Cc: Linus Torvalds Cc: Peter Zijlstra Signed-off-by: Ingo Molnar

x86/retpoline: Support retpoline builds with Clang

2018-02-20T10:17:58Z

Signed-off-by: David Woodhouse Reviewed-by: Thomas Gleixner Cc: Linus Torvalds Cc: Peter Zijlstra 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

Merge branch 'x86-pti-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2018-01-14T23:30:02Z

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

x86/retpoline: Remove compile time warning

2018-01-14T21:29:36Z

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 Signed-off-by: Thomas Gleixner Cc: David Woodhouse Cc: Peter Zijlstra (Intel) Cc: gnomes@lxorguk.ukuu.org.uk Cc: Rik van Riel Cc: Andi Kleen Cc: Josh Poimboeuf Cc: thomas.lendacky@amd.com Cc: Linus Torvalds Cc: Jiri Kosina Cc: Andy Lutomirski Cc: Dave Hansen Cc: Kees Cook Cc: Tim Chen Cc: Greg Kroah-Hartman Link: https://lkml.kernel.org/r/CA+55aFzWgquv4i6Mab6bASqYXg3ErV3XDFEYf=GEcCDQg5uAtw@mail.gmail.com

Merge branch 'x86-pti-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2018-01-14T17:51:25Z

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 ...

x86/retpoline: Add initial retpoline support

2018-01-11T23:14:28Z

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 Signed-off-by: Thomas Gleixner Acked-by: Arjan van de Ven Acked-by: Ingo Molnar Cc: gnomes@lxorguk.ukuu.org.uk Cc: Rik van Riel Cc: Andi Kleen Cc: Josh Poimboeuf Cc: thomas.lendacky@amd.com Cc: Peter Zijlstra Cc: Linus Torvalds Cc: Jiri Kosina Cc: Andy Lutomirski Cc: Dave Hansen Cc: Kees Cook Cc: Tim Chen Cc: Greg Kroah-Hartman Cc: Paul Turner Link: https://lkml.kernel.org/r/1515707194-20531-4-git-send-email-dwmw@amazon.co.uk