Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.
code
Clone this repository
https://tangled.org/tjh.dev/kernel
git@gordian.tjh.dev:tjh.dev/kernel
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Pull timer update from Thomas Gleixner:
"New defines for the compat time* types so they can be shared between
32bit and 64bit builds. Not used yet, but merging them now allows the
actual conversions to be merged through different maintainer trees
without dependencies
We still have compat interfaces for 32bit on 64bit even with the new
2038 safe timespec/val variants because pointer size is different. And
for the old style timespec/val interfaces we need yet another 'compat'
interface for both 32bit native and 32bit on 64bit"
* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
y2038: Provide aliases for compat helpers
Pull IDA updates from Matthew Wilcox:
"A better IDA API:
id = ida_alloc(ida, GFP_xxx);
ida_free(ida, id);
rather than the cumbersome ida_simple_get(), ida_simple_remove().
The new IDA API is similar to ida_simple_get() but better named. The
internal restructuring of the IDA code removes the bitmap
preallocation nonsense.
I hope the net -200 lines of code is convincing"
* 'ida-4.19' of git://git.infradead.org/users/willy/linux-dax: (29 commits)
ida: Change ida_get_new_above to return the id
ida: Remove old API
test_ida: check_ida_destroy and check_ida_alloc
test_ida: Convert check_ida_conv to new API
test_ida: Move ida_check_max
test_ida: Move ida_check_leaf
idr-test: Convert ida_check_nomem to new API
ida: Start new test_ida module
target/iscsi: Allocate session IDs from an IDA
iscsi target: fix session creation failure handling
drm/vmwgfx: Convert to new IDA API
dmaengine: Convert to new IDA API
ppc: Convert vas ID allocation to new IDA API
media: Convert entity ID allocation to new IDA API
ppc: Convert mmu context allocation to new IDA API
Convert net_namespace to new IDA API
cb710: Convert to new IDA API
rsxx: Convert to new IDA API
osd: Convert to new IDA API
sd: Convert to new IDA API
...
As part of the system call rework for 64-bit time_t, we are restructuring
the way that compat syscalls deal with 32-bit time_t, reusing the
implementation for 32-bit architectures. Christoph Hellwig suggested a
rename of the associated types and interfaces to avoid the confusing usage
of the 'compat' prefix for 32-bit architectures.
To prepare for doing that in linux-4.20, add a set of macros that allows to
convert subsystems separately to the new names and avoids some of the
nastier merge conflicts.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Christoph Hellwig <hch@lst.de>
Cc: y2038@lists.linaro.org
Cc: John Stultz <john.stultz@linaro.org>
Cc: Deepa Dinamani <deepa.kernel@gmail.com>
Link: https://lkml.kernel.org/r/20180821203329.2089473-1-arnd@arndb.de
Pull gcc plugin fix from Kees Cook:
"Lift gcc test into Kconfig. This is for better behavior when the
kernel is built with Clang, reported by Stefan Agner"
* tag 'gcc-plugins-v4.19-rc1-fix' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
gcc-plugins: Disable when building under Clang
This calling convention makes more sense for the implementation as well
as the callers. It even shaves 32 bytes off the compiled code size.
Signed-off-by: Matthew Wilcox <willy@infradead.org>
It turns out that we should *not* invert all not-present mappings,
because the all zeroes case is obviously special.
clear_page() does not undergo the XOR logic to invert the address bits,
i.e. PTE, PMD and PUD entries that have not been individually written
will have val=0 and so will trigger __pte_needs_invert(). As a result,
{pte,pmd,pud}_pfn() will return the wrong PFN value, i.e. all ones
(adjusted by the max PFN mask) instead of zero. A zeroed entry is ok
because the page at physical address 0 is reserved early in boot
specifically to mitigate L1TF, so explicitly exempt them from the
inversion when reading the PFN.
Manifested as an unexpected mprotect(..., PROT_NONE) failure when called
on a VMA that has VM_PFNMAP and was mmap'd to as something other than
PROT_NONE but never used. mprotect() sends the PROT_NONE request down
prot_none_walk(), which walks the PTEs to check the PFNs.
prot_none_pte_entry() gets the bogus PFN from pte_pfn() and returns
-EACCES because it thinks mprotect() is trying to adjust a high MMIO
address.
[ This is a very modified version of Sean's original patch, but all
credit goes to Sean for doing this and also pointing out that
sometimes the __pte_needs_invert() function only gets the protection
bits, not the full eventual pte. But zero remains special even in
just protection bits, so that's ok. - Linus ]
Fixes: f22cc87f6c1f ("x86/speculation/l1tf: Invert all not present mappings")
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Acked-by: Andi Kleen <ak@linux.intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull perf updates from Thomas Gleixner:
"Kernel:
- Improve kallsyms coverage
- Add x86 entry trampolines to kcore
- Fix ARM SPE handling
- Correct PPC event post processing
Tools:
- Make the build system more robust
- Small fixes and enhancements all over the place
- Update kernel ABI header copies
- Preparatory work for converting libtraceevnt to a shared library
- License cleanups"
* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (100 commits)
tools arch: Update arch/x86/lib/memcpy_64.S copy used in 'perf bench mem memcpy'
tools arch x86: Update tools's copy of cpufeatures.h
perf python: Fix pyrf_evlist__read_on_cpu() interface
perf mmap: Store real cpu number in 'struct perf_mmap'
perf tools: Remove ext from struct kmod_path
perf tools: Add gzip_is_compressed function
perf tools: Add lzma_is_compressed function
perf tools: Add is_compressed callback to compressions array
perf tools: Move the temp file processing into decompress_kmodule
perf tools: Use compression id in decompress_kmodule()
perf tools: Store compression id into struct dso
perf tools: Add compression id into 'struct kmod_path'
perf tools: Make is_supported_compression() static
perf tools: Make decompress_to_file() function static
perf tools: Get rid of dso__needs_decompress() call in __open_dso()
perf tools: Get rid of dso__needs_decompress() call in symbol__disassemble()
perf tools: Get rid of dso__needs_decompress() call in read_object_code()
tools lib traceevent: Change to SPDX License format
perf llvm: Allow passing options to llc in addition to clang
perf parser: Improve error message for PMU address filters
...
Prior to doing compiler feature detection in Kconfig, attempts to build
GCC plugins with Clang would fail the build, much in the same way missing
GCC plugin headers would fail the build. However, now that this logic
has been lifted into Kconfig, add an explicit test for GCC (instead of
duplicating it in the feature-test script).
Reported-by: Stefan Agner <stefan@agner.ch>
Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Delete ida_pre_get(), ida_get_new(), ida_get_new_above() and ida_remove()
from the public API. Some of these functions still exist as internal
helpers, but they should not be called by consumers.
Signed-off-by: Matthew Wilcox <willy@infradead.org>
Pull device mapper updates from Mike Snitzer:
- A couple stable fixes for the DM writecache target.
- A stable fix for the DM cache target that fixes the potential for
data corruption after an unclean shutdown of a cache device using
writeback mode.
- Update DM integrity target to allow the metadata to be stored on a
separate device from data.
- Fix DM kcopyd and the snapshot target to cond_resched() where
appropriate and be more efficient with processing completed work.
- A few fixes and improvements for DM crypt.
- Add DM delay target feature to configure delay of flushes independent
of writes.
- Update DM thin-provisioning target to include metadata_low_watermark
threshold in pool status.
- Fix stale DM thin-provisioning Documentation.
* tag 'for-4.19/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm: (26 commits)
dm writecache: fix a crash due to reading past end of dirty_bitmap
dm crypt: don't decrease device limits
dm cache metadata: set dirty on all cache blocks after a crash
dm snapshot: remove stale FIXME in snapshot_map()
dm snapshot: improve performance by switching out_of_order_list to rbtree
dm kcopyd: avoid softlockup in run_complete_job
dm cache metadata: save in-core policy_hint_size to on-disk superblock
dm thin: stop no_space_timeout worker when switching to write-mode
dm kcopyd: return void from dm_kcopyd_copy()
dm thin: include metadata_low_watermark threshold in pool status
dm writecache: report start_sector in status line
dm crypt: convert essiv from ahash to shash
dm crypt: use wake_up_process() instead of a wait queue
dm integrity: recalculate checksums on creation
dm integrity: flush journal on suspend when using separate metadata device
dm integrity: use version 2 for separate metadata
dm integrity: allow separate metadata device
dm integrity: add ic->start in get_data_sector()
dm integrity: report provided data sectors in the status
dm integrity: implement fair range locks
...
Pull x86 fixes from Thomas Gleixner:
- Correct the L1TF fallout on 32bit and the off by one in the 'too much
RAM for protection' calculation.
- Add a helpful kernel message for the 'too much RAM' case
- Unbreak the VDSO in case that the compiler desides to use indirect
jumps/calls and emits retpolines which cannot be resolved because the
kernel uses its own thunks, which does not work for the VDSO. Make it
use the builtin thunks.
- Re-export start_thread() which was unexported when the 32/64bit
implementation was unified. start_thread() is required by modular
binfmt handlers.
- Trivial cleanups
* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/speculation/l1tf: Suggest what to do on systems with too much RAM
x86/speculation/l1tf: Fix off-by-one error when warning that system has too much RAM
x86/kvm/vmx: Remove duplicate l1d flush definitions
x86/speculation/l1tf: Fix overflow in l1tf_pfn_limit() on 32bit
x86/process: Re-export start_thread()
x86/mce: Add notifier_block forward declaration
x86/vdso: Fix vDSO build if a retpoline is emitted
Pull perf/core improvements and fixes from Arnaldo Carvalho de Melo:
LLVM/clang/eBPF: (Arnaldo Carvalho de Melo)
- Allow passing options to llc in addition to to clang.
Hardware tracing: (Jack Henschel)
- Improve error message for PMU address filters, clarifying availability of
that feature in hardware having hardware tracing such as Intel PT.
Python interface: (Jiri Olsa)
- Fix read_on_cpu() interface.
ELF/DWARF libraries: (Jiri Olsa)
- Fix handling of the combo compressed module file + decompressed associated
debuginfo file.
Build (Rasmus Villemoes)
- Disable parallelism for 'make clean', avoiding multiple submakes deleting
the same files and causing the build to fail on systems such as Yocto.
Kernel ABI copies: (Arnaldo Carvalho de Melo)
- Update tools's copy of x86's cpufeatures.h.
- Update arch/x86/lib/memcpy_64.S copy used in 'perf bench mem memcpy'.
Miscellaneous: (Steven Rostedt)
- Change libtraceevent to SPDX License format.
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The layout of Makefile.gcc-plugins had uneven tabs, and the long names
of things made this file a bit hard to quickly visually parse. This
breaks lines and moves options to the same tab depth. While we're at
it, this also adds some comments about the various sections.
Signed-off-by: Kees Cook <keescook@chromium.org>
Move these tests from the userspace test-suite to the kernel test-suite.
Also convert check_ida_random to the new API.
Signed-off-by: Matthew Wilcox <willy@infradead.org>