kernel/linux.git/include/asm-generic/vmlinux.lds.h, branch v4.4.270

vmlinux.lds.h: Add PGO and AutoFDO input sections

2021-01-17T12:55:13+00:00

commit eff8728fe69880d3f7983bec3fb6cea4c306261f upstream. Basically, consider .text.{hot|unlikely|unknown}.* part of .text, too. When compiling with profiling information (collected via PGO instrumentations or AutoFDO sampling), Clang will separate code into .text.hot, .text.unlikely, or .text.unknown sections based on profiling information. After D79600 (clang-11), these sections will have a trailing `.` suffix, ie. .text.hot., .text.unlikely., .text.unknown.. When using -ffunction-sections together with profiling infomation, either explicitly (FGKASLR) or implicitly (LTO), code may be placed in sections following the convention: .text.hot., .text.unlikely., .text.unknown. where , , and are functions. (This produces one section per function; we generally try to merge these all back via linker script so that we don't have 50k sections). For the above cases, we need to teach our linker scripts that such sections might exist and that we'd explicitly like them grouped together, otherwise we can wind up with code outside of the _stext/_etext boundaries that might not be mapped properly for some architectures, resulting in boot failures. If the linker script is not told about possible input sections, then where the section is placed as output is a heuristic-laiden mess that's non-portable between linkers (ie. BFD and LLD), and has resulted in many hard to debug bugs. Kees Cook is working on cleaning this up by adding --orphan-handling=warn linker flag used in ARCH=powerpc to additional architectures. In the case of linker scripts, borrowing from the Zen of Python: explicit is better than implicit. Also, ld.bfd's internal linker script considers .text.hot AND .text.hot.* to be part of .text, as well as .text.unlikely and .text.unlikely.*. I didn't see support for .text.unknown.*, and didn't see Clang producing such code in our kernel builds, but I see code in LLVM that can produce such section names if profiling information is missing. That may point to a larger issue with generating or collecting profiles, but I would much rather be safe and explicit than have to debug yet another issue related to orphan section placement. Reported-by: Jian Cai Suggested-by: Fāng-ruì Sòng Signed-off-by: Nick Desaulniers Signed-off-by: Kees Cook Signed-off-by: Ingo Molnar Tested-by: Luis Lozano Tested-by: Manoj Gupta Acked-by: Kees Cook Cc: linux-arch@vger.kernel.org Cc: stable@vger.kernel.org Link: https://sourceware.org/git/?p=binutils-gdb.git;a=commitdiff;h=add44f8d5c5c05e08b11e033127a744d61c26aee Link: https://sourceware.org/git/?p=binutils-gdb.git;a=commitdiff;h=1de778ed23ce7492c523d5850c6c6dbb34152655 Link: https://reviews.llvm.org/D79600 Link: https://bugs.chromium.org/p/chromium/issues/detail?id=1084760 Link: https://lore.kernel.org/r/20200821194310.3089815-7-keescook@chromium.org Debugged-by: Luis Lozano [nc: Fix conflicts around lack of TEXT_MAIN, NOINSTR_TEXT, and .text..refcount] Signed-off-by: Nathan Chancellor Signed-off-by: Greg Kroah-Hartman

kaiser: cleanups while trying for gold link

2018-01-05T14:44:24+00:00

While trying to get our gold link to work, four cleanups: matched the gdt_page declaration to its definition; in fiddling unsuccessfully with PERCPU_INPUT(), lined up backslashes; lined up the backslashes according to convention in percpu-defs.h; deleted the unused irq_stack_pointer addition to irq_stack_union. Sad to report that aligning backslashes does not appear to help gold align to 8192: but while these did not help, they are worth keeping. Signed-off-by: Hugh Dickins Acked-by: Jiri Kosina Signed-off-by: Greg Kroah-Hartman

KAISER: Kernel Address Isolation

2018-01-05T14:44:23+00:00

This patch introduces our implementation of KAISER (Kernel Address Isolation to have Side-channels Efficiently Removed), a kernel isolation technique to close hardware side channels on kernel address information. More information about the patch can be found on: https://github.com/IAIK/KAISER From: Richard Fellner From: Daniel Gruss X-Subject: [RFC, PATCH] x86_64: KAISER - do not map kernel in user mode Date: Thu, 4 May 2017 14:26:50 +0200 Link: http://marc.info/?l=linux-kernel&m=149390087310405&w=2 Kaiser-4.10-SHA1: c4b1831d44c6144d3762ccc72f0c4e71a0c713e5 To: To: Cc: Cc: Cc: Michael Schwarz Cc: Richard Fellner Cc: Ingo Molnar Cc: Cc: After several recent works [1,2,3] KASLR on x86_64 was basically considered dead by many researchers. We have been working on an efficient but effective fix for this problem and found that not mapping the kernel space when running in user mode is the solution to this problem [4] (the corresponding paper [5] will be presented at ESSoS17). With this RFC patch we allow anybody to configure their kernel with the flag CONFIG_KAISER to add our defense mechanism. If there are any questions we would love to answer them. We also appreciate any comments! Cheers, Daniel (+ the KAISER team from Graz University of Technology) [1] http://www.ieee-security.org/TC/SP2013/papers/4977a191.pdf [2] https://www.blackhat.com/docs/us-16/materials/us-16-Fogh-Using-Undocumented-CPU-Behaviour-To-See-Into-Kernel-Mode-And-Break-KASLR-In-The-Process.pdf [3] https://www.blackhat.com/docs/us-16/materials/us-16-Jang-Breaking-Kernel-Address-Space-Layout-Randomization-KASLR-With-Intel-TSX.pdf [4] https://github.com/IAIK/KAISER [5] https://gruss.cc/files/kaiser.pdf [patch based also on https://raw.githubusercontent.com/IAIK/KAISER/master/KAISER/0001-KAISER-Kernel-Address-Isolation.patch] Signed-off-by: Richard Fellner Signed-off-by: Moritz Lipp Signed-off-by: Daniel Gruss Signed-off-by: Michael Schwarz Acked-by: Jiri Kosina Signed-off-by: Hugh Dickins Signed-off-by: Greg Kroah-Hartman

vmlinux.lds: account for destructor sections

2016-08-10T09:49:25+00:00

commit e41f501d391265ff568f3e49d6128cc30856a36f upstream. If CONFIG_KASAN is enabled and gcc is configured with --disable-initfini-array and/or gold linker is used, gcc emits .ctors/.dtors and .text.startup/.text.exit sections instead of .init_array/.fini_array. .dtors section is not explicitly accounted in the linker script and messes vvar/percpu layout. We want: ffffffff822bfd80 D _edata ffffffff822c0000 D __vvar_beginning_hack ffffffff822c0000 A __vvar_page ffffffff822c0080 0000000000000098 D vsyscall_gtod_data ffffffff822c1000 A __init_begin ffffffff822c1000 D init_per_cpu__irq_stack_union ffffffff822c1000 A __per_cpu_load ffffffff822d3000 D init_per_cpu__gdt_page We got: ffffffff8279a600 D _edata ffffffff8279b000 A __vvar_page ffffffff8279c000 A __init_begin ffffffff8279c000 D init_per_cpu__irq_stack_union ffffffff8279c000 A __per_cpu_load ffffffff8279e000 D __vvar_beginning_hack ffffffff8279e080 0000000000000098 D vsyscall_gtod_data ffffffff827ae000 D init_per_cpu__gdt_page This happens because __vvar_page and .vvar get different addresses in arch/x86/kernel/vmlinux.lds.S: . = ALIGN(PAGE_SIZE); __vvar_page = .; .vvar : AT(ADDR(.vvar) - LOAD_OFFSET) { /* work around gold bug 13023 */ __vvar_beginning_hack = .; Discard .dtors/.fini_array/.text.exit, since we don't call dtors. Merge .text.startup into init text. Link: http://lkml.kernel.org/r/1467386363-120030-1-git-send-email-dvyukov@google.com Signed-off-by: Dmitry Vyukov Reviewed-by: Andrey Ryabinin Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

clocksource / ACPI: Add probing infrastructure for ACPI-based clocksources

2015-10-01T00:18:38+00:00

DT enjoys a rather nice probing infrastructure for clocksources, while ACPI is so far stuck into a very distant past. This patch introduces a declarative API, allowing clocksources to be self-contained and be called when parsing the GTDT table. Signed-off-by: Marc Zyngier Acked-by: Thomas Gleixner Tested-by: Hanjun Guo Signed-off-by: Rafael J. Wysocki

irqchip / ACPI: Add probing infrastructure for ACPI-based irqchips

2015-10-01T00:18:38+00:00

DT enjoys a rather nice probing infrastructure for irqchips, while ACPI is so far stuck into a very distant past. This patch introduces a declarative API, allowing irqchips to be self-contained and be called when a particular entry is matched in the MADT table. Signed-off-by: Marc Zyngier Acked-by: Catalin Marinas Reviewed-by: Hanjun Guo Acked-by: Thomas Gleixner Tested-by: Hanjun Guo Signed-off-by: Rafael J. Wysocki

ACPI: Add early device probing infrastructure

2015-10-01T00:18:38+00:00

IRQ controllers and timers are the two types of device the kernel requires before being able to use the device driver model. ACPI so far lacks a proper probing infrastructure similar to the one we have with DT, where we're able to declare IRQ chips and clocksources inside the driver code, and let the core code pick it up and call us back on a match. This leads to all kind of really ugly hacks all over the arm64 code and even in the ACPI layer. In order to allow some basic probing based on the ACPI tables, introduce "struct acpi_probe_entry" which contains just enough data and callbacks to match a table, an optional subtable, and call a probe function. A driver can, at build time, register itself and expect being called if the right entry exists in the ACPI table. A acpi_probe_device_table() is provided, taking an identifier for a set of acpi_prove_entries, and iterating over the registered entries. Signed-off-by: Marc Zyngier Reviewed-by: Lorenzo Pieralisi Reviewed-by: Hanjun Guo Acked-by: Thomas Gleixner Tested-by: Hanjun Guo Signed-off-by: Rafael J. Wysocki

kbuild: Fix .text.unlikely placement

2015-08-20T12:55:54+00:00

When building a kernel with .text.unlikely text the unlikely text for each translation unit was put next to the main .text code in the final vmlinux. The problem is that the linker doesn't allow more specific submatches of a section name in a different linker script statement after the main match. So we need to move them all into one line. With that change .text.unlikely is at the end of everything again. I also moved .text.hot into the same statement though, even though that's not strictly needed. Signed-off-by: Andi Kleen Signed-off-by: Michal Marek

Merge tag 'tty-4.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty

2015-04-21T16:33:10+00:00

Pull tty/serial updates from Greg KH: "Here's the big tty/serial driver update for 4.1-rc1. It was delayed for a bit due to some questions surrounding some of the console command line parsing changes that are in here. There's still one tiny regression for people who were previously putting multiple console command lines and expecting them all to be ignored for some odd reason, but Peter is working on fixing that. If not, I'll send a revert for the offending patch, but I have faith that Peter can address it. Other than the console work here, there's the usual serial driver updates and changes, and a buch of 8250 reworks to try to make that driver easier to maintain over time, and have it support more devices in the future. All of these have been in linux-next for a while" * tag 'tty-4.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (119 commits) n_gsm: Drop unneeded cast on netdev_priv sc16is7xx: expose RTS inversion in RS-485 mode serial: 8250_pci: port failed after wakeup from S3 earlycon: 8250: Document kernel command line options earlycon: 8250: Fix command line regression earlycon: Fix __earlycon_table stride tty: clean up the tty time logic a bit serial: 8250_dw: only get the clock rate in one place serial: 8250_dw: remove useless ACPI ID check dmaengine: hsu: move memory allocation to GFP_NOWAIT dmaengine: hsu: remove redundant pieces of code serial: 8250_pci: add Intel Tangier support dmaengine: hsu: add Intel Tangier PCI ID serial: 8250_pci: replace switch-case by formula for Intel MID serial: 8250_pci: replace switch-case by formula tty: cpm_uart: replace CONFIG_8xx by CONFIG_CPM1 serial: jsm: some off by one bugs serial: xuartps: Fix check in console_setup(). serial: xuartps: Get rid of register access macros. serial: xuartps: Fix iobase use. ...

Merge branch 'for-linus' of git://ftp.arm.linux.org.uk/~rmk/linux-arm

2015-04-15T04:03:26+00:00

Pull ARM updates from Russell King: "Included in this update are both some long term fixes and some new features. Fixes: - An integer overflow in the calculation of ELF_ET_DYN_BASE. - Avoiding OOMs for high-order IOMMU allocations - SMP requires the data cache to be enabled for synchronisation primitives to work, so prevent the CPU_DCACHE_DISABLE option being visible on SMP builds. - A bug going back 10+ years in the noMMU ARM94* CPU support code, where it corrupts registers. Found by folk getting Linux running on their cameras. - Versatile Express needs an errata workaround enabled for CPU hot-unplug to work. Features: - Clean up module linker by handling out of range relocations separately from relocation cases we don't handle. - Fix a long term bug in the pci_mmap_page_range() code, which we hope won't impact userspace (we hope there's no users of the existing broken interface.) - Don't map DMA coherent allocations when we don't have a MMU. - Drop experimental status for SMP_ON_UP. - Warn when DT doesn't specify ePAPR mandatory cache properties. - Add documentation concerning how we find the start of physical memory for AUTO_ZRELADDR kernels, detailing why we have chosen the mask and the implications of changing it. - Updates from Ard Biesheuvel to address some issues with large kernels (such as allyesconfig) failing to link. - Allow hibernation to work on modern (ARMv7) CPUs - this appears to have never worked in the past on these CPUs. - Enable IRQ_SHOW_LEVEL, which changes the /proc/interrupts output format (hopefully without userspace breaking... let's hope that if it causes someone a problem, they tell us.) - Fix tegra-ahb DT offsets. - Rework ARM errata 643719 code (and ARMv7 flush_cache_louis()/ flush_dcache_all()) code to be more efficient, and enable this errata workaround by default for ARMv7+SMP CPUs. This complements the Versatile Express fix above. - Rework ARMv7 context code for errata 430973, so that only Cortex A8 CPUs are impacted by the branch target buffer flush when this errata is enabled. Also update the help text to indicate that all r1p* A8 CPUs are impacted. - Switch ARM to the generic show_mem() implementation, it conveys all the information which we were already reporting. - Prevent slow timer sources being used for udelay() - timers running at less than 1MHz are not useful for this, and can cause udelay() to return immediately, without any wait. Using such a slow timer is silly. - VDSO support for 32-bit ARM, mainly for gettimeofday() using the ARM architected timer. - Perf support for Scorpion performance monitoring units" vdso semantic conflict fixed up as per linux-next. * 'for-linus' of git://ftp.arm.linux.org.uk/~rmk/linux-arm: (52 commits) ARM: update errata 430973 documentation to cover Cortex A8 r1p* ARM: ensure delay timer has sufficient accuracy for delays ARM: switch to use the generic show_mem() implementation ARM: proc-v7: avoid errata 430973 workaround for non-Cortex A8 CPUs ARM: enable ARM errata 643719 workaround by default ARM: cache-v7: optimise test for Cortex A9 r0pX devices ARM: cache-v7: optimise branches in v7_flush_cache_louis ARM: cache-v7: consolidate initialisation of cache level index ARM: cache-v7: shift CLIDR to extract appropriate field before masking ARM: cache-v7: use movw/movt instructions ARM: allow 16-bit instructions in ALT_UP() ARM: proc-arm94*.S: fix setup function ARM: vexpress: fix CPU hotplug with CT9x4 tile. ARM: 8276/1: Make CPU_DCACHE_DISABLE depend on !SMP ARM: 8335/1: Documentation: DT bindings: Tegra AHB: document the legacy base address ARM: 8334/1: amba: tegra-ahb: detect and correct bogus base address ARM: 8333/1: amba: tegra-ahb: fix register offsets in the macros ARM: 8339/1: Enable CONFIG_GENERIC_IRQ_SHOW_LEVEL ARM: 8338/1: kexec: Relax SMP validation to improve DT compatibility ARM: 8337/1: mm: Do not invoke OOM for higher order IOMMU DMA allocations ...