Fork of hrdl's(https://git.sr.ht/~hrdl/linux)
'hrdl-pinenote-6.15rc3 branch, rebased to 6.15. hrdl's branch is itself a fork of m-weigand's (https://github.com/m-weigand/linux) v6.12 branch.
22b3548861
Brenden Blanco says: ==================== Add driver bpf hook for early packet drop and forwarding This patch set introduces new infrastructure for programmatically processing packets in the earliest stages of rx, as part of an effort others are calling eXpress Data Path (XDP) [1]. Start this effort by introducing a new bpf program type for early packet filtering, before even an skb has been allocated. Extend on this with the ability to modify packet data and send back out on the same port. Patch 1 adds an API for bulk bpf prog refcnt incrememnt. Patch 2 introduces the new prog type and helpers for validating the bpf program. A new userspace struct is defined containing only data and data_end as fields, with others to follow in the future. In patch 3, create a new ndo to pass the fd to supported drivers. In patch 4, expose a new rtnl option to userspace. In patch 5, enable support in mlx4 driver. In patch 6, create a sample drop and count program. With single core, achieved ~20 Mpps drop rate on a 40G ConnectX3-Pro. This includes packet data access, bpf array lookup, and increment. In patch 7, add a page recycle facility to mlx4 rx, enabled when xdp is active. In patch 8, add the XDP_TX type to bpf.h In patch 9, add helper in tx patch for writing tx_desc In patch 10, add support in mlx4 for packet data write and forwarding In patch 11, turn on packet write support in the bpf verifier In patch 12, add a sample program for packet write and forwarding. With single core, achieved ~10 Mpps rewrite and forwarding. [1] https://github.com/iovisor/bpf-docs/blob/master/Express_Data_Path.pdf v10: 1/12: Add bulk refcnt api. 5/12: Move prog from priv to ring. This attribute is still only set globally, but the path to finer granularity should be clear. No lock is taken, so some rings may operate on older programs for a time (one napi loop). Looked into options such as napi_synchronize, but they were deemed too slow (calls to msleep). Rename prog to xdp_prog. Add xdp_ring_num to help with accounting, used more heavily in later patches. 7/12: Adjust to use per-ring xdp prog. Use priv->xdp_ring_num where before priv->prog was used to determine buffer allocations. 9/12: Add cpu_to_be16 to vlan_tag in mxl4_en_xmit(). Remove unused variable from mlx4_en_xmit and unused params from build_inline_wqe. v9: 4/11: Add missing newline in en_err message. 6/11: Move page_cache cleanup from mlx4_en_destroy_rx_ring to mlx4_en_deactivate_rx_ring. Move mlx4_en_moderation_update back to static. Remove calls to mlx4_en_alloc/free_resources in mlx4_xdp_set. Adopt instead the approach of mlx4_en_change_mtu to use a watchdog. 9/11: Use a per-ring function pointer in tx to separate out the code for regular and recycle paths of tx completion handling. Add a helper function to init the recycle ring and callback, called just after activating tx. Remove extra tx ring resource requirement, and instead steal from the upper rings. This helps to avoid needing mlx4_en_alloc_resources. Add some hopefully meaningful error messages for the various error cases. Reverted some of the hard-to-follow logic that was accounting for the extra tx rings. v8: 1/11: Reduce WARN_ONCE to single line. Also, change act param of that function to u32 to match return type of bpf_prog_run_xdp. 2/11: Clarify locking semantics in ndo comment. 4/11: Add en_err warning in mlx4_xdp_set on num_frags/mtu violation. v7: Addressing two of the major discussion points: return codes and ndo. The rest will be taken as todo items for separate patches. Add an XDP_ABORTED type, which explicitly falls through to DROP. The same result must be taken for the default case as well, as it is now well-defined API behavior. Merge ndo_xdp_* into a single ndo. The style is similar to ndo_setup_tc, but with less unidirectional naming convention. The IFLA parameter names are unchanged. TODOs: Add ethtool per-ring stats for aborted, default cases, maybe even drop and tx as well. Avoid duplicate dma sync operation in XDP_PASS case as mentioned by Saeed. 1/12: Add XDP_ABORTED enum, reword API comment, and update commit message. 2/12: Rewrite ndo_xdp_*() into single ndo_xdp() with type/union style calling convention. 3/12: Switch to ndo_xdp callback. 4/12: Add XDP_ABORTED case as a fall-through to XDP_DROP. Implement ndo_xdp. 12/12: Dropped, this will need some more work. v6: 2/12: drop unnecessary netif_device_present check 4/12, 6/12, 9/12: Reorder default case statement above drop case to remove some copy/paste. v5: 0/12: Rebase and remove previous 1/13 patch 1/12: Fix nits from Daniel. Left the (void *) cast as-is, to be fixed in future. Add bpf_warn_invalid_xdp_action() helper, to be used when out of bounds action is returned by the program. Add a comment to bpf.h denoting the undefined nature of out of bounds returns. 2/12: Switch to using bpf_prog_get_type(). Rename ndo_xdp_get() to ndo_xdp_attached(). 3/12: Add IFLA_XDP as a nested type, and add the associated nla_policy for the new subtypes IFLA_XDP_FD and IFLA_XDP_ATTACHED. 4/12: Fixup the use of READ_ONCE in the ndos. Add a user of bpf_warn_invalid_xdp_action helper. 5/12: Adjust to using the nested netlink options. 6/12: kbuild was complaining about overflow of u16 on tile architecture...bump frag_stride to u32. The page_offset member that is computed from this was already u32. v4: 2/12: Add inline helper for calling xdp bpf prog under rcu 3/12: Add detail to ndo comments 5/12: Remove mlx4_call_xdp and use inline helper instead. 6/12: Fix checkpatch complaints 9/12: Introduce new patch 9/12 with common helper for tx_desc write Refactor to use common tx_desc write helper 11/12: Fix checkpatch complaints v3: Rewrite from v2 trying to incorporate feedback from multiple sources. Specifically, add ability to forward packets out the same port and allow packet modification. For packet forwarding, the driver reserves a dedicated set of tx rings for exclusive use by xdp. Upon completion, the pages on this ring are recycled directly back to a small per-rx-ring page cache without being dma unmapped. Use of the percpu skb is dropped in favor of a lightweight struct xdp_buff. The direct packet access feature is leveraged to remove dependence on the skb. The mlx4 driver implementation allocates a page-per-packet and maps it in PCI_DMA_BIDIRECTIONAL mode when the bpf program is activated. Naming is converted to use "xdp" instead of "phys_dev". v2: 1/5: Drop xdp from types, instead consistently use bpf_phys_dev_ Introduce enum for return values from phys_dev hook 2/5: Move prog->type check to just before invoking ndo Change ndo to take a bpf_prog * instead of fd Add ndo_bpf_get rather than keeping a bool in the netdev struct 3/5: Use ndo_bpf_get to fetch bool 4/5: Enforce that only 1 frag is ever given to bpf prog by disallowing mtu to increase beyond FRAG_SZ0 when bpf prog is running, or conversely to set a bpf prog when priv->num_frags > 1 Rename pseudo_skb to bpf_phys_dev_md Implement ndo_bpf_get Add dma sync just before invoking prog Check for explicit bpf return code rather than nonzero Remove increment of rx_dropped 5/5: Use explicit bpf return code in example Update commit log with higher pps numbers ==================== Signed-off-by: David S. Miller <davem@davemloft.net> |
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| Documentation | ||
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| firmware | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
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| tools | ||
| usr | ||
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| .get_maintainer.ignore | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
| REPORTING-BUGS | ||
Linux kernel release 4.x <http://kernel.org/>
These are the release notes for Linux version 4. Read them carefully,
as they tell you what this is all about, explain how to install the
kernel, and what to do if something goes wrong.
WHAT IS LINUX?
Linux is a clone of the operating system Unix, written from scratch by
Linus Torvalds with assistance from a loosely-knit team of hackers across
the Net. It aims towards POSIX and Single UNIX Specification compliance.
It has all the features you would expect in a modern fully-fledged Unix,
including true multitasking, virtual memory, shared libraries, demand
loading, shared copy-on-write executables, proper memory management,
and multistack networking including IPv4 and IPv6.
It is distributed under the GNU General Public License - see the
accompanying COPYING file for more details.
ON WHAT HARDWARE DOES IT RUN?
Although originally developed first for 32-bit x86-based PCs (386 or higher),
today Linux also runs on (at least) the Compaq Alpha AXP, Sun SPARC and
UltraSPARC, Motorola 68000, PowerPC, PowerPC64, ARM, Hitachi SuperH, Cell,
IBM S/390, MIPS, HP PA-RISC, Intel IA-64, DEC VAX, AMD x86-64, AXIS CRIS,
Xtensa, Tilera TILE, AVR32, ARC and Renesas M32R architectures.
Linux is easily portable to most general-purpose 32- or 64-bit architectures
as long as they have a paged memory management unit (PMMU) and a port of the
GNU C compiler (gcc) (part of The GNU Compiler Collection, GCC). Linux has
also been ported to a number of architectures without a PMMU, although
functionality is then obviously somewhat limited.
Linux has also been ported to itself. You can now run the kernel as a
userspace application - this is called UserMode Linux (UML).
DOCUMENTATION:
- There is a lot of documentation available both in electronic form on
the Internet and in books, both Linux-specific and pertaining to
general UNIX questions. I'd recommend looking into the documentation
subdirectories on any Linux FTP site for the LDP (Linux Documentation
Project) books. This README is not meant to be documentation on the
system: there are much better sources available.
- There are various README files in the Documentation/ subdirectory:
these typically contain kernel-specific installation notes for some
drivers for example. See Documentation/00-INDEX for a list of what
is contained in each file. Please read the Changes file, as it
contains information about the problems, which may result by upgrading
your kernel.
- The Documentation/DocBook/ subdirectory contains several guides for
kernel developers and users. These guides can be rendered in a
number of formats: PostScript (.ps), PDF, HTML, & man-pages, among others.
After installation, "make psdocs", "make pdfdocs", "make htmldocs",
or "make mandocs" will render the documentation in the requested format.
INSTALLING the kernel source:
- If you install the full sources, put the kernel tarball in a
directory where you have permissions (e.g. your home directory) and
unpack it:
xz -cd linux-4.X.tar.xz | tar xvf -
Replace "X" with the version number of the latest kernel.
Do NOT use the /usr/src/linux area! This area has a (usually
incomplete) set of kernel headers that are used by the library header
files. They should match the library, and not get messed up by
whatever the kernel-du-jour happens to be.
- You can also upgrade between 4.x releases by patching. Patches are
distributed in the xz format. To install by patching, get all the
newer patch files, enter the top level directory of the kernel source
(linux-4.X) and execute:
xz -cd ../patch-4.x.xz | patch -p1
Replace "x" for all versions bigger than the version "X" of your current
source tree, _in_order_, and you should be ok. You may want to remove
the backup files (some-file-name~ or some-file-name.orig), and make sure
that there are no failed patches (some-file-name# or some-file-name.rej).
If there are, either you or I have made a mistake.
Unlike patches for the 4.x kernels, patches for the 4.x.y kernels
(also known as the -stable kernels) are not incremental but instead apply
directly to the base 4.x kernel. For example, if your base kernel is 4.0
and you want to apply the 4.0.3 patch, you must not first apply the 4.0.1
and 4.0.2 patches. Similarly, if you are running kernel version 4.0.2 and
want to jump to 4.0.3, you must first reverse the 4.0.2 patch (that is,
patch -R) _before_ applying the 4.0.3 patch. You can read more on this in
Documentation/applying-patches.txt
Alternatively, the script patch-kernel can be used to automate this
process. It determines the current kernel version and applies any
patches found.
linux/scripts/patch-kernel linux
The first argument in the command above is the location of the
kernel source. Patches are applied from the current directory, but
an alternative directory can be specified as the second argument.
- Make sure you have no stale .o files and dependencies lying around:
cd linux
make mrproper
You should now have the sources correctly installed.
SOFTWARE REQUIREMENTS
Compiling and running the 4.x kernels requires up-to-date
versions of various software packages. Consult
Documentation/Changes for the minimum version numbers required
and how to get updates for these packages. Beware that using
excessively old versions of these packages can cause indirect
errors that are very difficult to track down, so don't assume that
you can just update packages when obvious problems arise during
build or operation.
BUILD directory for the kernel:
When compiling the kernel, all output files will per default be
stored together with the kernel source code.
Using the option "make O=output/dir" allows you to specify an alternate
place for the output files (including .config).
Example:
kernel source code: /usr/src/linux-4.X
build directory: /home/name/build/kernel
To configure and build the kernel, use:
cd /usr/src/linux-4.X
make O=/home/name/build/kernel menuconfig
make O=/home/name/build/kernel
sudo make O=/home/name/build/kernel modules_install install
Please note: If the 'O=output/dir' option is used, then it must be
used for all invocations of make.
CONFIGURING the kernel:
Do not skip this step even if you are only upgrading one minor
version. New configuration options are added in each release, and
odd problems will turn up if the configuration files are not set up
as expected. If you want to carry your existing configuration to a
new version with minimal work, use "make oldconfig", which will
only ask you for the answers to new questions.
- Alternative configuration commands are:
"make config" Plain text interface.
"make menuconfig" Text based color menus, radiolists & dialogs.
"make nconfig" Enhanced text based color menus.
"make xconfig" Qt based configuration tool.
"make gconfig" GTK+ based configuration tool.
"make oldconfig" Default all questions based on the contents of
your existing ./.config file and asking about
new config symbols.
"make silentoldconfig"
Like above, but avoids cluttering the screen
with questions already answered.
Additionally updates the dependencies.
"make olddefconfig"
Like above, but sets new symbols to their default
values without prompting.
"make defconfig" Create a ./.config file by using the default
symbol values from either arch/$ARCH/defconfig
or arch/$ARCH/configs/${PLATFORM}_defconfig,
depending on the architecture.
"make ${PLATFORM}_defconfig"
Create a ./.config file by using the default
symbol values from
arch/$ARCH/configs/${PLATFORM}_defconfig.
Use "make help" to get a list of all available
platforms of your architecture.
"make allyesconfig"
Create a ./.config file by setting symbol
values to 'y' as much as possible.
"make allmodconfig"
Create a ./.config file by setting symbol
values to 'm' as much as possible.
"make allnoconfig" Create a ./.config file by setting symbol
values to 'n' as much as possible.
"make randconfig" Create a ./.config file by setting symbol
values to random values.
"make localmodconfig" Create a config based on current config and
loaded modules (lsmod). Disables any module
option that is not needed for the loaded modules.
To create a localmodconfig for another machine,
store the lsmod of that machine into a file
and pass it in as a LSMOD parameter.
target$ lsmod > /tmp/mylsmod
target$ scp /tmp/mylsmod host:/tmp
host$ make LSMOD=/tmp/mylsmod localmodconfig
The above also works when cross compiling.
"make localyesconfig" Similar to localmodconfig, except it will convert
all module options to built in (=y) options.
You can find more information on using the Linux kernel config tools
in Documentation/kbuild/kconfig.txt.
- NOTES on "make config":
- Having unnecessary drivers will make the kernel bigger, and can
under some circumstances lead to problems: probing for a
nonexistent controller card may confuse your other controllers
- Compiling the kernel with "Processor type" set higher than 386
will result in a kernel that does NOT work on a 386. The
kernel will detect this on bootup, and give up.
- A kernel with math-emulation compiled in will still use the
coprocessor if one is present: the math emulation will just
never get used in that case. The kernel will be slightly larger,
but will work on different machines regardless of whether they
have a math coprocessor or not.
- The "kernel hacking" configuration details usually result in a
bigger or slower kernel (or both), and can even make the kernel
less stable by configuring some routines to actively try to
break bad code to find kernel problems (kmalloc()). Thus you
should probably answer 'n' to the questions for "development",
"experimental", or "debugging" features.
COMPILING the kernel:
- Make sure you have at least gcc 3.2 available.
For more information, refer to Documentation/Changes.
Please note that you can still run a.out user programs with this kernel.
- Do a "make" to create a compressed kernel image. It is also
possible to do "make install" if you have lilo installed to suit the
kernel makefiles, but you may want to check your particular lilo setup first.
To do the actual install, you have to be root, but none of the normal
build should require that. Don't take the name of root in vain.
- If you configured any of the parts of the kernel as `modules', you
will also have to do "make modules_install".
- Verbose kernel compile/build output:
Normally, the kernel build system runs in a fairly quiet mode (but not
totally silent). However, sometimes you or other kernel developers need
to see compile, link, or other commands exactly as they are executed.
For this, use "verbose" build mode. This is done by passing
"V=1" to the "make" command, e.g.
make V=1 all
To have the build system also tell the reason for the rebuild of each
target, use "V=2". The default is "V=0".
- Keep a backup kernel handy in case something goes wrong. This is
especially true for the development releases, since each new release
contains new code which has not been debugged. Make sure you keep a
backup of the modules corresponding to that kernel, as well. If you
are installing a new kernel with the same version number as your
working kernel, make a backup of your modules directory before you
do a "make modules_install".
Alternatively, before compiling, use the kernel config option
"LOCALVERSION" to append a unique suffix to the regular kernel version.
LOCALVERSION can be set in the "General Setup" menu.
- In order to boot your new kernel, you'll need to copy the kernel
image (e.g. .../linux/arch/i386/boot/bzImage after compilation)
to the place where your regular bootable kernel is found.
- Booting a kernel directly from a floppy without the assistance of a
bootloader such as LILO, is no longer supported.
If you boot Linux from the hard drive, chances are you use LILO, which
uses the kernel image as specified in the file /etc/lilo.conf. The
kernel image file is usually /vmlinuz, /boot/vmlinuz, /bzImage or
/boot/bzImage. To use the new kernel, save a copy of the old image
and copy the new image over the old one. Then, you MUST RERUN LILO
to update the loading map! If you don't, you won't be able to boot
the new kernel image.
Reinstalling LILO is usually a matter of running /sbin/lilo.
You may wish to edit /etc/lilo.conf to specify an entry for your
old kernel image (say, /vmlinux.old) in case the new one does not
work. See the LILO docs for more information.
After reinstalling LILO, you should be all set. Shutdown the system,
reboot, and enjoy!
If you ever need to change the default root device, video mode,
ramdisk size, etc. in the kernel image, use the 'rdev' program (or
alternatively the LILO boot options when appropriate). No need to
recompile the kernel to change these parameters.
- Reboot with the new kernel and enjoy.
IF SOMETHING GOES WRONG:
- If you have problems that seem to be due to kernel bugs, please check
the file MAINTAINERS to see if there is a particular person associated
with the part of the kernel that you are having trouble with. If there
isn't anyone listed there, then the second best thing is to mail
them to me (torvalds@linux-foundation.org), and possibly to any other
relevant mailing-list or to the newsgroup.
- In all bug-reports, *please* tell what kernel you are talking about,
how to duplicate the problem, and what your setup is (use your common
sense). If the problem is new, tell me so, and if the problem is
old, please try to tell me when you first noticed it.
- If the bug results in a message like
unable to handle kernel paging request at address C0000010
Oops: 0002
EIP: 0010:XXXXXXXX
eax: xxxxxxxx ebx: xxxxxxxx ecx: xxxxxxxx edx: xxxxxxxx
esi: xxxxxxxx edi: xxxxxxxx ebp: xxxxxxxx
ds: xxxx es: xxxx fs: xxxx gs: xxxx
Pid: xx, process nr: xx
xx xx xx xx xx xx xx xx xx xx
or similar kernel debugging information on your screen or in your
system log, please duplicate it *exactly*. The dump may look
incomprehensible to you, but it does contain information that may
help debugging the problem. The text above the dump is also
important: it tells something about why the kernel dumped code (in
the above example, it's due to a bad kernel pointer). More information
on making sense of the dump is in Documentation/oops-tracing.txt
- If you compiled the kernel with CONFIG_KALLSYMS you can send the dump
as is, otherwise you will have to use the "ksymoops" program to make
sense of the dump (but compiling with CONFIG_KALLSYMS is usually preferred).
This utility can be downloaded from
ftp://ftp.<country>.kernel.org/pub/linux/utils/kernel/ksymoops/ .
Alternatively, you can do the dump lookup by hand:
- In debugging dumps like the above, it helps enormously if you can
look up what the EIP value means. The hex value as such doesn't help
me or anybody else very much: it will depend on your particular
kernel setup. What you should do is take the hex value from the EIP
line (ignore the "0010:"), and look it up in the kernel namelist to
see which kernel function contains the offending address.
To find out the kernel function name, you'll need to find the system
binary associated with the kernel that exhibited the symptom. This is
the file 'linux/vmlinux'. To extract the namelist and match it against
the EIP from the kernel crash, do:
nm vmlinux | sort | less
This will give you a list of kernel addresses sorted in ascending
order, from which it is simple to find the function that contains the
offending address. Note that the address given by the kernel
debugging messages will not necessarily match exactly with the
function addresses (in fact, that is very unlikely), so you can't
just 'grep' the list: the list will, however, give you the starting
point of each kernel function, so by looking for the function that
has a starting address lower than the one you are searching for but
is followed by a function with a higher address you will find the one
you want. In fact, it may be a good idea to include a bit of
"context" in your problem report, giving a few lines around the
interesting one.
If you for some reason cannot do the above (you have a pre-compiled
kernel image or similar), telling me as much about your setup as
possible will help. Please read the REPORTING-BUGS document for details.
- Alternatively, you can use gdb on a running kernel. (read-only; i.e. you
cannot change values or set break points.) To do this, first compile the
kernel with -g; edit arch/i386/Makefile appropriately, then do a "make
clean". You'll also need to enable CONFIG_PROC_FS (via "make config").
After you've rebooted with the new kernel, do "gdb vmlinux /proc/kcore".
You can now use all the usual gdb commands. The command to look up the
point where your system crashed is "l *0xXXXXXXXX". (Replace the XXXes
with the EIP value.)
gdb'ing a non-running kernel currently fails because gdb (wrongly)
disregards the starting offset for which the kernel is compiled.