wireguard-linux/arch/x86/entry/calling.h, branch jd/unified-crypt-queue

context_tracking: Rename context_tracking_is_enabled() => context_tracking_enabled()

2019-10-29T09:01:12Z

Remove the superfluous "is" in the middle of the name. We want to standardize the naming so that it can be expanded through suffixes: context_tracking_enabled() context_tracking_enabled_cpu() context_tracking_enabled_this_cpu() Signed-off-by: Frederic Weisbecker Signed-off-by: Peter Zijlstra (Intel) Cc: Jacek Anaszewski Cc: Linus Torvalds Cc: Pavel Machek Cc: Peter Zijlstra Cc: Rafael J . Wysocki Cc: Rik van Riel Cc: Thomas Gleixner Cc: Viresh Kumar Cc: Wanpeng Li Cc: Yauheni Kaliuta Link: https://lkml.kernel.org/r/20191016025700.31277-6-frederic@kernel.org Signed-off-by: Ingo Molnar

Merge branch master from git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git

2019-07-28T20:22:40Z

Pick up the spectre documentation so the Grand Schemozzle can be added.

x86/paravirt: Make read_cr2() CALLEE_SAVE

2019-07-17T21:17:37Z

The one paravirt read_cr2() implementation (Xen) is actually quite trivial and doesn't need to clobber anything other than the return register. Making read_cr2() CALLEE_SAVE avoids all the PUSH/POP nonsense and allows more convenient use from assembly. Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Thomas Gleixner Reviewed-by: Juergen Gross Cc: bp@alien8.de Cc: rostedt@goodmis.org Cc: luto@kernel.org Cc: torvalds@linux-foundation.org Cc: hpa@zytor.com Cc: dave.hansen@linux.intel.com Cc: zhe.he@windriver.com Cc: joel@joelfernandes.org Cc: devel@etsukata.com Link: https://lkml.kernel.org/r/20190711114335.887392493@infradead.org

x86/speculation: Prepare entry code for Spectre v1 swapgs mitigations

2019-07-09T12:11:45Z

Spectre v1 isn't only about array bounds checks. It can affect any conditional checks. The kernel entry code interrupt, exception, and NMI handlers all have conditional swapgs checks. Those may be problematic in the context of Spectre v1, as kernel code can speculatively run with a user GS. For example: if (coming from user space) swapgs mov %gs:, %reg mov (%reg), %reg1 When coming from user space, the CPU can speculatively skip the swapgs, and then do a speculative percpu load using the user GS value. So the user can speculatively force a read of any kernel value. If a gadget exists which uses the percpu value as an address in another load/store, then the contents of the kernel value may become visible via an L1 side channel attack. A similar attack exists when coming from kernel space. The CPU can speculatively do the swapgs, causing the user GS to get used for the rest of the speculative window. The mitigation is similar to a traditional Spectre v1 mitigation, except: a) index masking isn't possible; because the index (percpu offset) isn't user-controlled; and b) an lfence is needed in both the "from user" swapgs path and the "from kernel" non-swapgs path (because of the two attacks described above). The user entry swapgs paths already have SWITCH_TO_KERNEL_CR3, which has a CR3 write when PTI is enabled. Since CR3 writes are serializing, the lfences can be skipped in those cases. On the other hand, the kernel entry swapgs paths don't depend on PTI. To avoid unnecessary lfences for the user entry case, create two separate features for alternative patching: X86_FEATURE_FENCE_SWAPGS_USER X86_FEATURE_FENCE_SWAPGS_KERNEL Use these features in entry code to patch in lfences where needed. The features aren't enabled yet, so there's no functional change. Signed-off-by: Josh Poimboeuf Signed-off-by: Thomas Gleixner Reviewed-by: Dave Hansen

x86/stackframe: Move ENCODE_FRAME_POINTER to asm/frame.h

2019-06-25T08:23:45Z

In preparation for wider use, move the ENCODE_FRAME_POINTER macros to a common header and provide inline asm versions. These macros are used to encode a pt_regs frame for the unwinder; see unwind_frame.c:decode_frame_pointer(). Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Josh Poimboeuf Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Signed-off-by: Ingo Molnar

jump_label: move 'asm goto' support test to Kconfig

2019-01-06T00:46:51Z

Currently, CONFIG_JUMP_LABEL just means "I _want_ to use jump label". The jump label is controlled by HAVE_JUMP_LABEL, which is defined like this: #if defined(CC_HAVE_ASM_GOTO) && defined(CONFIG_JUMP_LABEL) # define HAVE_JUMP_LABEL #endif We can improve this by testing 'asm goto' support in Kconfig, then make JUMP_LABEL depend on CC_HAS_ASM_GOTO. Ugly #ifdef HAVE_JUMP_LABEL will go away, and CONFIG_JUMP_LABEL will match to the real kernel capability. Signed-off-by: Masahiro Yamada Acked-by: Michael Ellerman (powerpc) Tested-by: Sedat Dilek

Revert "x86/jump-labels: Macrofy inline assembly code to work around GCC inlining bugs"

2018-12-19T10:58:10Z

This reverts commit 5bdcd510c2ac9efaf55c4cbd8d46421d8e2320cd. The macro based workarounds for GCC's inlining bugs caused regressions: distcc and other distro build setups broke, and the fixes are not easy nor will they solve regressions on already existing installations. So we are reverting this patch and the 8 followup patches. What makes this revert easier is that GCC9 will likely include the new 'asm inline' syntax that makes inlining of assembly blocks a lot more robust. This is a superior method to any macro based hackeries - and might even be backported to GCC8, which would make all modern distros get the inlining fixes as well. Many thanks to Masahiro Yamada and others for helping sort out these problems. Reported-by: Masahiro Yamada Reviewed-by: Borislav Petkov Reviewed-by: Thomas Gleixner Cc: Juergen Gross Cc: Richard Biener Cc: Kees Cook Cc: Segher Boessenkool Cc: Ard Biesheuvel Cc: Peter Zijlstra Cc: Josh Poimboeuf Cc: Nadav Amit Cc: Linus Torvalds Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar

Merge tag 'stackleak-v4.20-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

2018-11-01T18:46:27Z

Pull stackleak gcc plugin from Kees Cook: "Please pull this new GCC plugin, stackleak, for v4.20-rc1. This plugin was ported from grsecurity by Alexander Popov. It provides efficient stack content poisoning at syscall exit. This creates a defense against at least two classes of flaws: - Uninitialized stack usage. (We continue to work on improving the compiler to do this in other ways: e.g. unconditional zero init was proposed to GCC and Clang, and more plugin work has started too). - Stack content exposure. By greatly reducing the lifetime of valid stack contents, exposures via either direct read bugs or unknown cache side-channels become much more difficult to exploit. This complements the existing buddy and heap poisoning options, but provides the coverage for stacks. The x86 hooks are included in this series (which have been reviewed by Ingo, Dave Hansen, and Thomas Gleixner). The arm64 hooks have already been merged through the arm64 tree (written by Laura Abbott and reviewed by Mark Rutland and Will Deacon). With VLAs having been removed this release, there is no need for alloca() protection, so it has been removed from the plugin" * tag 'stackleak-v4.20-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: arm64: Drop unneeded stackleak_check_alloca() stackleak: Allow runtime disabling of kernel stack erasing doc: self-protection: Add information about STACKLEAK feature fs/proc: Show STACKLEAK metrics in the /proc file system lkdtm: Add a test for STACKLEAK gcc-plugins: Add STACKLEAK plugin for tracking the kernel stack x86/entry: Add STACKLEAK erasing the kernel stack at the end of syscalls

x86/jump-labels: Macrofy inline assembly code to work around GCC inlining bugs

2018-10-06T13:52:17Z

As described in: 77b0bf55bc67: ("kbuild/Makefile: Prepare for using macros in inline assembly code to work around asm() related GCC inlining bugs") GCC's inlining heuristics are broken with common asm() patterns used in kernel code, resulting in the effective disabling of inlining. The workaround is to set an assembly macro and call it from the inline assembly block - which is also a minor cleanup for the jump-label code. As a result the code size is slightly increased, but inlining decisions are better: text data bss dec hex filename 18163528 10226300 2957312 31347140 1de51c4 ./vmlinux before 18163608 10227348 2957312 31348268 1de562c ./vmlinux after (+1128) And functions such as intel_pstate_adjust_policy_max(), kvm_cpu_accept_dm_intr(), kvm_register_readl() are inlined. Tested-by: Kees Cook Signed-off-by: Nadav Amit Acked-by: Peter Zijlstra (Intel) Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Brian Gerst Cc: Denys Vlasenko Cc: Greg Kroah-Hartman Cc: Kate Stewart Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Philippe Ombredanne Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/20181005202718.229565-4-namit@vmware.com Link: https://lore.kernel.org/lkml/20181003213100.189959-11-namit@vmware.com/T/#u Signed-off-by: Ingo Molnar

x86/entry: Add STACKLEAK erasing the kernel stack at the end of syscalls

2018-09-04T17:35:47Z

The STACKLEAK feature (initially developed by PaX Team) has the following benefits: 1. Reduces the information that can be revealed through kernel stack leak bugs. The idea of erasing the thread stack at the end of syscalls is similar to CONFIG_PAGE_POISONING and memzero_explicit() in kernel crypto, which all comply with FDP_RIP.2 (Full Residual Information Protection) of the Common Criteria standard. 2. Blocks some uninitialized stack variable attacks (e.g. CVE-2017-17712, CVE-2010-2963). That kind of bugs should be killed by improving C compilers in future, which might take a long time. This commit introduces the code filling the used part of the kernel stack with a poison value before returning to userspace. Full STACKLEAK feature also contains the gcc plugin which comes in a separate commit. The STACKLEAK feature is ported from grsecurity/PaX. More information at: https://grsecurity.net/ https://pax.grsecurity.net/ This code is modified from Brad Spengler/PaX Team's code in the last public patch of grsecurity/PaX based on our understanding of the code. Changes or omissions from the original code are ours and don't reflect the original grsecurity/PaX code. Performance impact: Hardware: Intel Core i7-4770, 16 GB RAM Test #1: building the Linux kernel on a single core 0.91% slowdown Test #2: hackbench -s 4096 -l 2000 -g 15 -f 25 -P 4.2% slowdown So the STACKLEAK description in Kconfig includes: "The tradeoff is the performance impact: on a single CPU system kernel compilation sees a 1% slowdown, other systems and workloads may vary and you are advised to test this feature on your expected workload before deploying it". Signed-off-by: Alexander Popov Acked-by: Thomas Gleixner Reviewed-by: Dave Hansen Acked-by: Ingo Molnar Signed-off-by: Kees Cook