mirror of
https://github.com/raspberrypi/linux.git
synced 2025-12-06 01:49:46 +00:00
775b3e09b7
Signed-off-by: popcornmix <popcornmix@gmail.com> usb: dwc: fix lockdep false positive Signed-off-by: Kari Suvanto <karis79@gmail.com> usb: dwc: fix inconsistent lock state Signed-off-by: Kari Suvanto <karis79@gmail.com> Add FIQ patch to dwc_otg driver. Enable with dwc_otg.fiq_fix_enable=1. Should give about 10% more ARM performance. Thanks to Gordon and Costas Avoid dynamic memory allocation for channel lock in USB driver. Thanks ddv2005. Add NAK holdoff scheme. Enabled by default, disable with dwc_otg.nak_holdoff_enable=0. Thanks gsh Make sure we wait for the reset to finish dwc_otg: fix bug in dwc_otg_hcd.c resulting in silent kernel memory corruption, escalating to OOPS under high USB load. dwc_otg: Fix unsafe access of QTD during URB enqueue In dwc_otg_hcd_urb_enqueue during qtd creation, it was possible that the transaction could complete almost immediately after the qtd was assigned to a host channel during URB enqueue, which meant the qtd pointer was no longer valid having been completed and removed. Usually, this resulted in an OOPS during URB submission. By predetermining whether transactions need to be queued or not, this unsafe pointer access is avoided. This bug was only evident on the Pi model A where a device was attached that had no periodic endpoints (e.g. USB pendrive or some wlan devices). dwc_otg: Fix incorrect URB allocation error handling If the memory allocation for a dwc_otg_urb failed, the kernel would OOPS because for some reason a member of the *unallocated* struct was set to zero. Error handling changed to fail correctly. dwc_otg: fix potential use-after-free case in interrupt handler If a transaction had previously aborted, certain interrupts are enabled to track error counts and reset where necessary. On IN endpoints the host generates an ACK interrupt near-simultaneously with completion of transfer. In the case where this transfer had previously had an error, this results in a use-after-free on the QTD memory space with a 1-byte length being overwritten to 0x00. dwc_otg: add handling of SPLIT transaction data toggle errors Previously a data toggle error on packets from a USB1.1 device behind a TT would result in the Pi locking up as the driver never handled the associated interrupt. Patch adds basic retry mechanism and interrupt acknowledgement to cater for either a chance toggle error or for devices that have a broken initial toggle state (FT8U232/FT232BM). dwc_otg: implement tasklet for returning URBs to usbcore hcd layer The dwc_otg driver interrupt handler for transfer completion will spend a very long time with interrupts disabled when a URB is completed - this is because usb_hcd_giveback_urb is called from within the handler which for a USB device driver with complicated processing (e.g. webcam) will take an exorbitant amount of time to complete. This results in missed completion interrupts for other USB packets which lead to them being dropped due to microframe overruns. This patch splits returning the URB to the usb hcd layer into a high-priority tasklet. This will have most benefit for isochronous IN transfers but will also have incidental benefit where multiple periodic devices are active at once. dwc_otg: fix NAK holdoff and allow on split transactions only This corrects a bug where if a single active non-periodic endpoint had at least one transaction in its qh, on frnum == MAX_FRNUM the qh would get skipped and never get queued again. This would result in a silent device until error detection (automatic or otherwise) would either reset the device or flush and requeue the URBs. Additionally the NAK holdoff was enabled for all transactions - this would potentially stall a HS endpoint for 1ms if a previous error state enabled this interrupt and the next response was a NAK. Fix so that only split transactions get held off. dwc_otg: Call usb_hcd_unlink_urb_from_ep with lock held in completion handler usb_hcd_unlink_urb_from_ep must be called with the HCD lock held. Calling it asynchronously in the tasklet was not safe (regression inc4564d4a1a). This change unlinks it from the endpoint prior to queueing it for handling in the tasklet, and also adds a check to ensure the urb is OK to be unlinked before doing so. NULL pointer dereference kernel oopses had been observed in usb_hcd_giveback_urb when a USB device was unplugged/replugged during data transfer. This effect was reproduced using automated USB port power control, hundreds of replug events were performed during active transfers to confirm that the problem was eliminated. USB fix using a FIQ to implement split transactions This commit adds a FIQ implementaion that schedules the split transactions using a FIQ so we don't get held off by the interrupt latency of Linux dwc_otg: fix device attributes and avoid kernel warnings on boot dcw_otg: avoid logging function that can cause panics See: https://github.com/raspberrypi/firmware/issues/21 Thanks to cleverca22 for fix dwc_otg: mask correct interrupts after transaction error recovery The dwc_otg driver will unmask certain interrupts on a transaction that previously halted in the error state in order to reset the QTD error count. The various fine-grained interrupt handlers do not consider that other interrupts besides themselves were unmasked. By disabling the two other interrupts only ever enabled in DMA mode for this purpose, we can avoid unnecessary function calls in the IRQ handler. This will also prevent an unneccesary FIQ interrupt from being generated if the FIQ is enabled. dwc_otg: fiq: prevent FIQ thrash and incorrect state passing to IRQ In the case of a transaction to a device that had previously aborted due to an error, several interrupts are enabled to reset the error count when a device responds. This has the side-effect of making the FIQ thrash because the hardware will generate multiple instances of a NAK on an IN bulk/interrupt endpoint and multiple instances of ACK on an OUT bulk/interrupt endpoint. Make the FIQ mask and clear the associated interrupts. Additionally, on non-split transactions make sure that only unmasked interrupts are cleared. This caused a hard-to-trigger but serious race condition when you had the combination of an endpoint awaiting error recovery and a transaction completed on an endpoint - due to the sequencing and timing of interrupts generated by the dwc_otg core, it was possible to confuse the IRQ handler. Fix function tracing dwc_otg: whitespace cleanup in dwc_otg_urb_enqueue dwc_otg: prevent OOPSes during device disconnects The dwc_otg_urb_enqueue function is thread-unsafe. In particular the access of urb->hcpriv, usb_hcd_link_urb_to_ep, dwc_otg_urb->qtd and friends does not occur within a critical section and so if a device was unplugged during activity there was a high chance that the usbcore hub_thread would try to disable the endpoint with partially- formed entries in the URB queue. This would result in BUG() or null pointer dereferences. Fix so that access of urb->hcpriv, enqueuing to the hardware and adding to usbcore endpoint URB lists is contained within a single critical section. dwc_otg: prevent BUG() in TT allocation if hub address is > 16 A fixed-size array is used to track TT allocation. This was previously set to 16 which caused a crash because dwc_otg_hcd_allocate_port would read past the end of the array. This was hit if a hub was plugged in which enumerated as addr > 16, due to previous device resets or unplugs. Also add #ifdef FIQ_DEBUG around hcd->hub_port_alloc[], which grows to a large size if 128 hub addresses are supported. This field is for debug only for tracking which frame an allocate happened in. dwc_otg: make channel halts with unknown state less damaging If the IRQ received a channel halt interrupt through the FIQ with no other bits set, the IRQ would not release the host channel and never complete the URB. Add catchall handling to treat as a transaction error and retry. dwc_otg: fiq_split: use TTs with more granularity This fixes certain issues with split transaction scheduling. - Isochronous multi-packet OUT transactions now hog the TT until they are completed - this prevents hubs aborting transactions if they get a periodic start-split out-of-order - Don't perform TT allocation on non-periodic endpoints - this allows simultaneous use of the TT's bulk/control and periodic transaction buffers This commit will mainly affect USB audio playback. dwc_otg: fix potential sleep while atomic during urb enqueue Fixes a regression introduced witheb1b482a. Kmalloc called from dwc_otg_hcd_qtd_add / dwc_otg_hcd_qtd_create did not always have the GPF_ATOMIC flag set. Force this flag when inside the larger critical section. dwc_otg: make fiq_split_enable imply fiq_fix_enable Failing to set up the FIQ correctly would result in "IRQ 32: nobody cared" errors in dmesg. dwc_otg: prevent crashes on host port disconnects Fix several issues resulting in crashes or inconsistent state if a Model A root port was disconnected. - Clean up queue heads properly in kill_urbs_in_qh_list by removing the empty QHs from the schedule lists - Set the halt status properly to prevent IRQ handlers from using freed memory - Add fiq_split related cleanup for saved registers - Make microframe scheduling reclaim host channels if active during a disconnect - Abort URBs with -ESHUTDOWN status response, informing device drivers so they respond in a more correct fashion and don't try to resubmit URBs - Prevent IRQ handlers from attempting to handle channel interrupts if the associated URB was dequeued (and the driver state was cleared) dwc_otg: prevent leaking URBs during enqueue A dwc_otg_urb would get leaked if the HCD enqueue function failed for any reason. Free the URB at the appropriate points. dwc_otg: Enable NAK holdoff for control split transactions Certain low-speed devices take a very long time to complete a data or status stage of a control transaction, producing NAK responses until they complete internal processing - the USB2.0 spec limit is up to 500mS. This causes the same type of interrupt storm as seen with USB-serial dongles prior toc8edb238. In certain circumstances, usually while booting, this interrupt storm could cause SD card timeouts. dwc_otg: Fix for occasional lockup on boot when doing a USB reset dwc_otg: Don't issue traffic to LS devices in FS mode Issuing low-speed packets when the root port is in full-speed mode causes the root port to stop responding. Explicitly fail when enqueuing URBs to a LS endpoint on a FS bus. Fix ARM architecture issue with local_irq_restore() If local_fiq_enable() is called before a local_irq_restore(flags) where the flags variable has the F bit set, the FIQ will be erroneously disabled. Fixup arch_local_irq_restore to avoid trampling the F bit in CPSR. Also fix some of the hacks previously implemented for previous dwc_otg incarnations. dwc_otg: fiq_fsm: Base commit for driver rewrite This commit removes the previous FIQ fixes entirely and adds fiq_fsm. This rewrite features much more complete support for split transactions and takes into account several OTG hardware bugs. High-speed isochronous transactions are also capable of being performed by fiq_fsm. All driver options have been removed and replaced with: - dwc_otg.fiq_enable (bool) - dwc_otg.fiq_fsm_enable (bool) - dwc_otg.fiq_fsm_mask (bitmask) - dwc_otg.nak_holdoff (unsigned int) Defaults are specified such that fiq_fsm behaves similarly to the previously implemented FIQ fixes. fiq_fsm: Push error recovery into the FIQ when fiq_fsm is used If the transfer associated with a QTD failed due to a bus error, the HCD would retry the transfer up to 3 times (implementing the USB2.0 three-strikes retry in software). Due to the masking mechanism used by fiq_fsm, it is only possible to pass a single interrupt through to the HCD per-transfer. In this instance host channels would fall off the radar because the error reset would function, but the subsequent channel halt would be lost. Push the error count reset into the FIQ handler. fiq_fsm: Implement timeout mechanism For full-speed endpoints with a large packet size, interrupt latency runs the risk of the FIQ starting a transaction too late in a full-speed frame. If the device is still transmitting data when EOF2 for the downstream frame occurs, the hub will disable the port. This change is not reflected in the hub status endpoint and the device becomes unresponsive. Prevent high-bandwidth transactions from being started too late in a frame. The mechanism is not guaranteed: a combination of bit stuffing and hub latency may still result in a device overrunning. fiq_fsm: fix bounce buffer utilisation for Isochronous OUT Multi-packet isochronous OUT transactions were subject to a few bounday bugs. Fix them. Audio playback is now much more robust: however, an issue stands with devices that have adaptive sinks - ALSA plays samples too fast. dwc_otg: Return full-speed frame numbers in HS mode The frame counter increments on every *microframe* in high-speed mode. Most device drivers expect this number to be in full-speed frames - this caused considerable confusion to e.g. snd_usb_audio which uses the frame counter to estimate the number of samples played. fiq_fsm: save PID on completion of interrupt OUT transfers Also add edge case handling for interrupt transports. Note that for periodic split IN, data toggles are unimplemented in the OTG host hardware - it unconditionally accepts any PID. fiq_fsm: add missing case for fiq_fsm_tt_in_use() Certain combinations of bitrate and endpoint activity could result in a periodic transaction erroneously getting started while the previous Isochronous OUT was still active. fiq_fsm: clear hcintmsk for aborted transactions Prevents the FIQ from erroneously handling interrupts on a timed out channel. fiq_fsm: enable by default fiq_fsm: fix dequeues for non-periodic split transactions If a dequeue happened between the SSPLIT and CSPLIT phases of the transaction, the HCD would never receive an interrupt. fiq_fsm: Disable by default fiq_fsm: Handle HC babble errors The HCTSIZ transfer size field raises a babble interrupt if the counter wraps. Handle the resulting interrupt in this case. dwc_otg: fix interrupt registration for fiq_enable=0 Additionally make the module parameter conditional for wherever hcd->fiq_state is touched. fiq_fsm: Enable by default dwc_otg: Fix various issues with root port and transaction errors Process the host port interrupts correctly (and don't trample them). Root port hotplug now functional again. Fix a few thinkos with the transaction error passthrough for fiq_fsm. fiq_fsm: Implement hack for Split Interrupt transactions Hubs aren't too picky about which endpoint we send Control type split transactions to. By treating Interrupt transfers as Control, it is possible to use the non-periodic queue in the OTG core as well as the non-periodic FIFOs in the hub itself. This massively reduces the microframe exclusivity/contention that periodic split transactions otherwise have to enforce. It goes without saying that this is a fairly egregious USB specification violation, but it works. Original idea by Hans Petter Selasky @ FreeBSD.org. dwc_otg: FIQ support on SMP. Set up FIQ stack and handler on Core 0 only. dwc_otg: introduce fiq_fsm_spin(un|)lock() SMP safety for the FIQ relies on register read-modify write cycles being completed in the correct order. Several places in the DWC code modify registers also touched by the FIQ. Protect these by a bare-bones lock mechanism. This also makes it possible to run the FIQ and IRQ handlers on different cores. fiq_fsm: fix build on bcm2708 and bcm2709 platforms dwc_otg: put some barriers back where they should be for UP bcm2709/dwc_otg: Setup FIQ on core 1 if >1 core active dwc_otg: fixup read-modify-write in critical paths Be more careful about read-modify-write on registers that the FIQ also touches. Guard fiq_fsm_spin_lock with fiq_enable check fiq_fsm: Falling out of the state machine isn't fatal This edge case can be hit if the port is disabled while the FIQ is in the middle of a transaction. Make the effects less severe. Also get rid of the useless return value.
Linux kernel release 3.x <http://kernel.org/>
These are the release notes for Linux version 3. 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 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 (eg. your home directory) and
unpack it:
gzip -cd linux-3.X.tar.gz | tar xvf -
or
bzip2 -dc linux-3.X.tar.bz2 | 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 3.x releases by patching. Patches are
distributed in the traditional gzip and the newer bzip2 format. To
install by patching, get all the newer patch files, enter the
top level directory of the kernel source (linux-3.X) and execute:
gzip -cd ../patch-3.x.gz | patch -p1
or
bzip2 -dc ../patch-3.x.bz2 | 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 3.x kernels, patches for the 3.x.y kernels
(also known as the -stable kernels) are not incremental but instead apply
directly to the base 3.x kernel. For example, if your base kernel is 3.0
and you want to apply the 3.0.3 patch, you must not first apply the 3.0.1
and 3.0.2 patches. Similarly, if you are running kernel version 3.0.2 and
want to jump to 3.0.3, you must first reverse the 3.0.2 patch (that is,
patch -R) _before_ applying the 3.0.3 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 3.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" allow you to specify an alternate
place for the output files (including .config).
Example:
kernel source code: /usr/src/linux-3.X
build directory: /home/name/build/kernel
To configure and build the kernel, use:
cd /usr/src/linux-3.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" X windows (Qt) based configuration tool.
"make gconfig" X windows (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 inserting
"V=1" in 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.