talos-op-linux/arch/xtensa/kernel, branch master

Merge tag 'xtensa-20200206' of git://github.com/jcmvbkbc/linux-xtensa

2020-02-07T20:22:29+00:00

Pull xtensa updates from Max Filippov: - reorganize exception vectors placement - small cleanups (drop unused functions/headers/defconfig entries, spelling fixes) * tag 'xtensa-20200206' of git://github.com/jcmvbkbc/linux-xtensa: xtensa: ISS: improve simcall assembly xtensa: reorganize vectors placement xtensa: separate SMP and XIP support xtensa: move fast exception handlers close to vectors arch/xtensa: fix Kconfig typos for HAVE_SMP xtensa: clean up optional XCHAL_* definitions xtensa: drop unused function fast_coprocessor_double xtensa: drop empty platform_* functions from platforms xtensa: clean up platform headers xtensa: drop set_except_vector declaration xtensa: configs: Cleanup old Kconfig IO scheduler options

xtensa: reorganize vectors placement

2020-02-05T05:57:02+00:00

Allow vectors to be either merged into the kernel .text or put at a fixed virtual address independently of XIP option. Drop option that puts vectors at a fixed offset from the kernel text. Add choice to Kconfig. Vectors at fixed virtual address may be useful for XIP-aware MTD support and for noMMU configurations with available IRAM. Configurations without VECBASE register must put their vectors at specific locations regardless of the selected option. All other configurations should happily use merged vectors. Signed-off-by: Max Filippov

xtensa: separate SMP and XIP support

2020-02-05T05:56:15+00:00

There's no real dependency between SMP and XIP, allow them to be selected together. Always define 2- and 4-argument SECTION_VECTOR macros, always use 4-argument macro for the secondary reset vector and always define relocation entry for it. Signed-off-by: Max Filippov

xtensa: move fast exception handlers close to vectors

2020-02-05T05:53:39+00:00

On XIP kernels it makes sense to have exception vectors and fast exception handlers together (in a fast memory). In addition, with MTD XIP support both vectors and fast exception handlers must be outside of the FLASH. Add section .exception.text and move fast exception handlers to it. Put it together with vectors when vectors are outside of the .text. Signed-off-by: Max Filippov

xtensa: drop unused function fast_coprocessor_double

2020-02-01T08:42:35+00:00

fast_coprocessor_double is not used since commit c658eac628aa ("[XTENSA] Add support for configurable registers and coprocessors"). Remove it. There should be no coprocessor exceptions generated in the exception handling paths while PS.EXCM is set. Signed-off-by: Max Filippov

xtensa: drop empty platform_* functions from platforms

2020-01-31T20:17:28+00:00

Provide missing default implementation for platform_init and drop copies of default platform_init, platform_setup and platform_heartbeet from platforms/*/setup.c Signed-off-by: Max Filippov

xtensa: clean up platform headers

2020-01-31T20:17:25+00:00

Drop include directives for irrelevant headers in asm/platform.h and its users. Sort remaining headers. Signed-off-by: Max Filippov

Merge tag 'threads-v5.6' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux

2020-01-30T03:38:34+00:00

Pull thread management updates from Christian Brauner: "Sargun Dhillon over the last cycle has worked on the pidfd_getfd() syscall. This syscall allows for the retrieval of file descriptors of a process based on its pidfd. A task needs to have ptrace_may_access() permissions with PTRACE_MODE_ATTACH_REALCREDS (suggested by Oleg and Andy) on the target. One of the main use-cases is in combination with seccomp's user notification feature. As a reminder, seccomp's user notification feature was made available in v5.0. It allows a task to retrieve a file descriptor for its seccomp filter. The file descriptor is usually handed of to a more privileged supervising process. The supervisor can then listen for syscall events caught by the seccomp filter of the supervisee and perform actions in lieu of the supervisee, usually emulating syscalls. pidfd_getfd() is needed to expand its uses. There are currently two major users that wait on pidfd_getfd() and one future user: - Netflix, Sargun said, is working on a service mesh where users should be able to connect to a dns-based VIP. When a user connects to e.g. 1.2.3.4:80 that runs e.g. service "foo" they will be redirected to an envoy process. This service mesh uses seccomp user notifications and pidfd to intercept all connect calls and instead of connecting them to 1.2.3.4:80 connects them to e.g. 127.0.0.1:8080. - LXD uses the seccomp notifier heavily to intercept and emulate mknod() and mount() syscalls for unprivileged containers/processes. With pidfd_getfd() more uses-cases e.g. bridging socket connections will be possible. - The patchset has also seen some interest from the browser corner. Right now, Firefox is using a SECCOMP_RET_TRAP sandbox managed by a broker process. In the future glibc will start blocking all signals during dlopen() rendering this type of sandbox impossible. Hence, in the future Firefox will switch to a seccomp-user-nofication based sandbox which also makes use of file descriptor retrieval. The thread for this can be found at https://sourceware.org/ml/libc-alpha/2019-12/msg00079.html With pidfd_getfd() it is e.g. possible to bridge socket connections for the supervisee (binding to a privileged port) and taking actions on file descriptors on behalf of the supervisee in general. Sargun's first version was using an ioctl on pidfds but various people pushed for it to be a proper syscall which he duely implemented as well over various review cycles. Selftests are of course included. I've also added instructions how to deal with merge conflicts below. There's also a small fix coming from the kernel mentee project to correctly annotate struct sighand_struct with __rcu to fix various sparse warnings. We've received a few more such fixes and even though they are mostly trivial I've decided to postpone them until after -rc1 since they came in rather late and I don't want to risk introducing build warnings. Finally, there's a new prctl() command PR_{G,S}ET_IO_FLUSHER which is needed to avoid allocation recursions triggerable by storage drivers that have userspace parts that run in the IO path (e.g. dm-multipath, iscsi, etc). These allocation recursions deadlock the device. The new prctl() allows such privileged userspace components to avoid allocation recursions by setting the PF_MEMALLOC_NOIO and PF_LESS_THROTTLE flags. The patch carries the necessary acks from the relevant maintainers and is routed here as part of prctl() thread-management." * tag 'threads-v5.6' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux: prctl: PR_{G,S}ET_IO_FLUSHER to support controlling memory reclaim sched.h: Annotate sighand_struct with __rcu test: Add test for pidfd getfd arch: wire up pidfd_getfd syscall pid: Implement pidfd_getfd syscall vfs, fdtable: Add fget_task helper

Merge branch 'work.openat2' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

2020-01-29T19:20:24+00:00

Pull openat2 support from Al Viro: "This is the openat2() series from Aleksa Sarai. I'm afraid that the rest of namei stuff will have to wait - it got zero review the last time I'd posted #work.namei, and there had been a leak in the posted series I'd caught only last weekend. I was going to repost it on Monday, but the window opened and the odds of getting any review during that... Oh, well. Anyway, openat2 part should be ready; that _did_ get sane amount of review and public testing, so here it comes" From Aleksa's description of the series: "For a very long time, extending openat(2) with new features has been incredibly frustrating. This stems from the fact that openat(2) is possibly the most famous counter-example to the mantra "don't silently accept garbage from userspace" -- it doesn't check whether unknown flags are present[1]. This means that (generally) the addition of new flags to openat(2) has been fraught with backwards-compatibility issues (O_TMPFILE has to be defined as __O_TMPFILE|O_DIRECTORY|[O_RDWR or O_WRONLY] to ensure old kernels gave errors, since it's insecure to silently ignore the flag[2]). All new security-related flags therefore have a tough road to being added to openat(2). Furthermore, the need for some sort of control over VFS's path resolution (to avoid malicious paths resulting in inadvertent breakouts) has been a very long-standing desire of many userspace applications. This patchset is a revival of Al Viro's old AT_NO_JUMPS[3] patchset (which was a variant of David Drysdale's O_BENEATH patchset[4] which was a spin-off of the Capsicum project[5]) with a few additions and changes made based on the previous discussion within [6] as well as others I felt were useful. In line with the conclusions of the original discussion of AT_NO_JUMPS, the flag has been split up into separate flags. However, instead of being an openat(2) flag it is provided through a new syscall openat2(2) which provides several other improvements to the openat(2) interface (see the patch description for more details). The following new LOOKUP_* flags are added: LOOKUP_NO_XDEV: Blocks all mountpoint crossings (upwards, downwards, or through absolute links). Absolute pathnames alone in openat(2) do not trigger this. Magic-link traversal which implies a vfsmount jump is also blocked (though magic-link jumps on the same vfsmount are permitted). LOOKUP_NO_MAGICLINKS: Blocks resolution through /proc/$pid/fd-style links. This is done by blocking the usage of nd_jump_link() during resolution in a filesystem. The term "magic-links" is used to match with the only reference to these links in Documentation/, but I'm happy to change the name. It should be noted that this is different to the scope of ~LOOKUP_FOLLOW in that it applies to all path components. However, you can do openat2(NO_FOLLOW|NO_MAGICLINKS) on a magic-link and it will *not* fail (assuming that no parent component was a magic-link), and you will have an fd for the magic-link. In order to correctly detect magic-links, the introduction of a new LOOKUP_MAGICLINK_JUMPED state flag was required. LOOKUP_BENEATH: Disallows escapes to outside the starting dirfd's tree, using techniques such as ".." or absolute links. Absolute paths in openat(2) are also disallowed. Conceptually this flag is to ensure you "stay below" a certain point in the filesystem tree -- but this requires some additional to protect against various races that would allow escape using "..". Currently LOOKUP_BENEATH implies LOOKUP_NO_MAGICLINKS, because it can trivially beam you around the filesystem (breaking the protection). In future, there might be similar safety checks done as in LOOKUP_IN_ROOT, but that requires more discussion. In addition, two new flags are added that expand on the above ideas: LOOKUP_NO_SYMLINKS: Does what it says on the tin. No symlink resolution is allowed at all, including magic-links. Just as with LOOKUP_NO_MAGICLINKS this can still be used with NOFOLLOW to open an fd for the symlink as long as no parent path had a symlink component. LOOKUP_IN_ROOT: This is an extension of LOOKUP_BENEATH that, rather than blocking attempts to move past the root, forces all such movements to be scoped to the starting point. This provides chroot(2)-like protection but without the cost of a chroot(2) for each filesystem operation, as well as being safe against race attacks that chroot(2) is not. If a race is detected (as with LOOKUP_BENEATH) then an error is generated, and similar to LOOKUP_BENEATH it is not permitted to cross magic-links with LOOKUP_IN_ROOT. The primary need for this is from container runtimes, which currently need to do symlink scoping in userspace[7] when opening paths in a potentially malicious container. There is a long list of CVEs that could have bene mitigated by having RESOLVE_THIS_ROOT (such as CVE-2017-1002101, CVE-2017-1002102, CVE-2018-15664, and CVE-2019-5736, just to name a few). In order to make all of the above more usable, I'm working on libpathrs[8] which is a C-friendly library for safe path resolution. It features a userspace-emulated backend if the kernel doesn't support openat2(2). Hopefully we can get userspace to switch to using it, and thus get openat2(2) support for free once it's ready. Future work would include implementing things like RESOLVE_NO_AUTOMOUNT and possibly a RESOLVE_NO_REMOTE (to allow programs to be sure they don't hit DoSes though stale NFS handles)" * 'work.openat2' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: Documentation: path-lookup: include new LOOKUP flags selftests: add openat2(2) selftests open: introduce openat2(2) syscall namei: LOOKUP_{IN_ROOT,BENEATH}: permit limited ".." resolution namei: LOOKUP_IN_ROOT: chroot-like scoped resolution namei: LOOKUP_BENEATH: O_BENEATH-like scoped resolution namei: LOOKUP_NO_XDEV: block mountpoint crossing namei: LOOKUP_NO_MAGICLINKS: block magic-link resolution namei: LOOKUP_NO_SYMLINKS: block symlink resolution namei: allow set_root() to produce errors namei: allow nd_jump_link() to produce errors nsfs: clean-up ns_get_path() signature to return int namei: only return -ECHILD from follow_dotdot_rcu()

Merge tag 'tty-5.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty

2020-01-29T18:13:27+00:00

Pull tty/serial driver updates from Greg KH: "Here are the big set of tty and serial driver updates for 5.6-rc1 Included in here are: - dummy_con cleanups (touches lots of arch code) - sysrq logic cleanups (touches lots of serial drivers) - samsung driver fixes (wasn't really being built) - conmakeshash move to tty subdir out of scripts - lots of small tty/serial driver updates All of these have been in linux-next for a while with no reported issues" * tag 'tty-5.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (140 commits) tty: n_hdlc: Use flexible-array member and struct_size() helper tty: baudrate: SPARC supports few more baud rates tty: baudrate: Synchronise baud_table[] and baud_bits[] tty: serial: meson_uart: Add support for kernel debugger serial: imx: fix a race condition in receive path serial: 8250_bcm2835aux: Document struct bcm2835aux_data serial: 8250_bcm2835aux: Use generic remapping code serial: 8250_bcm2835aux: Allocate uart_8250_port on stack serial: 8250_bcm2835aux: Suppress register_port error on -EPROBE_DEFER serial: 8250_bcm2835aux: Suppress clk_get error on -EPROBE_DEFER serial: 8250_bcm2835aux: Fix line mismatch on driver unbind serial_core: Remove unused member in uart_port vt: Correct comment documenting do_take_over_console() vt: Delete comment referencing non-existent unbind_con_driver() arch/xtensa/setup: Drop dummy_con initialization arch/x86/setup: Drop dummy_con initialization arch/unicore32/setup: Drop dummy_con initialization arch/sparc/setup: Drop dummy_con initialization arch/sh/setup: Drop dummy_con initialization arch/s390/setup: Drop dummy_con initialization ...