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Now that we have get_random_u32_below(), it's nearly trivial to make
inline helpers to compute get_random_u32_above() and
get_random_u32_inclusive(), which will help clean up open coded loops
and manual computations throughout the tree.
One snag is that in order to make get_random_u32_inclusive() operate on
closed intervals, we have to do some (unlikely) special case handling if
get_random_u32_inclusive(0, U32_MAX) is called. The least expensive way
of doing this is actually to adjust the slowpath of
get_random_u32_below() to have its undefined 0 result just return the
output of get_random_u32(). We can make this basically free by calling
get_random_u32() before the branch, so that the branch latency gets
interleaved.
Cc: stable@vger.kernel.org # to ease future backports that use this api
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Until the very recent commits, many bounded random integers were
calculated using `get_random_u32() % max_plus_one`, which not only
incurs the price of a division -- indicating performance mostly was not
a real issue -- but also does not result in a uniformly distributed
output if max_plus_one is not a power of two. Recent commits moved to
using `prandom_u32_max(max_plus_one)`, which replaces the division with
a faster multiplication, but still does not solve the issue with
non-uniform output.
For some users, maybe this isn't a problem, and for others, maybe it is,
but for the majority of users, probably the question has never been
posed and analyzed, and nobody thought much about it, probably assuming
random is random is random. In other words, the unthinking expectation
of most users is likely that the resultant numbers are uniform.
So we implement here an efficient way of generating uniform bounded
random integers. Through use of compile-time evaluation, and avoiding
divisions as much as possible, this commit introduces no measurable
overhead. At least for hot-path uses tested, any potential difference
was lost in the noise. On both clang and gcc, code generation is pretty
small.
The new function, get_random_u32_below(), lives in random.h, rather than
prandom.h, and has a "get_random_xxx" function name, because it is
suitable for all uses, including cryptography.
In order to be efficient, we implement a kernel-specific variant of
Daniel Lemire's algorithm from "Fast Random Integer Generation in an
Interval", linked below. The kernel's variant takes advantage of
constant folding to avoid divisions entirely in the vast majority of
cases, works on both 32-bit and 64-bit architectures, and requests a
minimal amount of bytes from the RNG.
Link: https://arxiv.org/pdf/1805.10941.pdf
Cc: stable@vger.kernel.org # to ease future backports that use this api
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
The intf_free() function frees the "intf" pointer so we cannot
dereference it again on the next line.
Fixes: cbb79863fc31 ("ipmi: Don't allow device module unload when in use")
Signed-off-by: Dan Carpenter <error27@gmail.com>
Message-Id: <Y3M8xa1drZv4CToE@kili>
Cc: <stable@vger.kernel.org> # 5.5+
Signed-off-by: Corey Minyard <cminyard@mvista.com>
The driver for XillyUSB devices maintains a kref reference count on each
xillyusb_dev structure, which represents a physical device. This reference
count reaches zero when the device has been disconnected and there are no
open file descriptors that are related to the device. When this occurs,
kref_put() calls cleanup_dev(), which clears up the device's data,
including the structure itself.
However, when xillyusb_open() is called, this reference count becomes
tricky: This function needs to obtain the xillyusb_dev structure that
relates to the inode's major and minor (as there can be several such).
xillybus_find_inode() (which is defined in xillybus_class.c) is called
for this purpose. xillybus_find_inode() holds a mutex that is global in
xillybus_class.c to protect the list of devices, and releases this
mutex before returning. As a result, nothing protects the xillyusb_dev's
reference counter from being decremented to zero before xillyusb_open()
increments it on its own behalf. Hence the structure can be freed
due to a rare race condition.
To solve this, a mutex is added. It is locked by xillyusb_open() before
the call to xillybus_find_inode() and is released only after the kref
counter has been incremented on behalf of the newly opened inode. This
protects the kref reference counters of all xillyusb_dev structs from
being decremented by xillyusb_disconnect() during this time segment, as
the call to kref_put() in this function is done with the same lock held.
There is no need to hold the lock on other calls to kref_put(), because
if xillybus_find_inode() finds a struct, xillyusb_disconnect() has not
made the call to remove it, and hence not made its call to kref_put(),
which takes place afterwards. Hence preventing xillyusb_disconnect's
call to kref_put() is enough to ensure that the reference doesn't reach
zero before it's incremented by xillyusb_open().
It would have been more natural to increment the reference count in
xillybus_find_inode() of course, however this function is also called by
Xillybus' driver for PCIe / OF, which registers a completely different
structure. Therefore, xillybus_find_inode() treats these structures as
void pointers, and accordingly can't make any changes.
Reported-by: Hyunwoo Kim <imv4bel@gmail.com>
Suggested-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Eli Billauer <eli.billauer@gmail.com>
Link: https://lore.kernel.org/r/20221030094209.65916-1-eli.billauer@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The kstrto<something>() functions have been moved from kernel.h to
kstrtox.h.
So, in order to eventually remove <linux/kernel.h> from <linux/watchdog.h>,
include the latter directly in the appropriate files.
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Message-Id: <37daa028845d90ee77f1e547121a051a983fec2e.1667647002.git.christophe.jaillet@wanadoo.fr>
Signed-off-by: Corey Minyard <cminyard@mvista.com>
The spec states that the minimum message retry time is 60ms, but it was
set to 20ms. Correct it.
Reported by: Tony Camuso <tcamuso@redhat.com>
Signed-off-by: Corey Minyard <cminyard@mvista.com>
While reworking the archrandom handling, commit d349ab99eec7 ("random:
handle archrandom with multiple longs") switched to the non-early
archrandom helpers in random_init(), which broke initialization of the
entropy pool from the arm64 random generator.
Indeed at that point the arm64 CPU features, which verify that all CPUs
have compatible capabilities, are not finalized so arch_get_random_seed_longs()
is unsuccessful. Instead random_init() should use the _early functions,
which check only the boot CPU on arm64. On other architectures the
_early functions directly call the normal ones.
Fixes: d349ab99eec7 ("random: handle archrandom with multiple longs")
Cc: stable@vger.kernel.org
Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
As of 1a3c7bb08826 ("PM: core: Add new *_PM_OPS macros, deprecate old
ones"), SIMPLE_DEV_PM_OPS() is deprecated in favor of
DEFINE_SIMPLE_DEV_PM_OPS(), which has the advantage that the PM callbacks
don't need to be wrapped with #ifdef CONFIG_PM or tagged with
__maybe_unused.
Convert to DEFINE_SIMPLE_DEV_PM_OPS(). No functional change intended.
Link: https://lore.kernel.org/r/20221025203852.681822-9-helgaas@kernel.org
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Dave Airlie <airlied@redhat.com>
As of 1a3c7bb08826 ("PM: core: Add new *_PM_OPS macros, deprecate old
ones"), SIMPLE_DEV_PM_OPS() is deprecated in favor of
DEFINE_SIMPLE_DEV_PM_OPS(), which has the advantage that the PM callbacks
don't need to be wrapped with #ifdef CONFIG_PM or tagged with
__maybe_unused.
Convert to DEFINE_SIMPLE_DEV_PM_OPS(). No functional change intended.
Link: https://lore.kernel.org/r/20221025203852.681822-8-helgaas@kernel.org
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Dave Airlie <airlied@redhat.com>
As of 1a3c7bb08826 ("PM: core: Add new *_PM_OPS macros, deprecate old
ones"), SIMPLE_DEV_PM_OPS() is deprecated in favor of
DEFINE_SIMPLE_DEV_PM_OPS(), which has the advantage that the PM callbacks
don't need to be wrapped with #ifdef CONFIG_PM or tagged with
__maybe_unused.
Convert to DEFINE_SIMPLE_DEV_PM_OPS(). No functional change intended.
Link: https://lore.kernel.org/r/20221025203852.681822-7-helgaas@kernel.org
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Dave Airlie <airlied@redhat.com>
Convert agpgart-nvidia from legacy PCI power management to the generic
power management framework.
Previously agpgart-nvidia used legacy PCI power management, and
agp_nvidia_suspend() and agp_nvidia_resume() were responsible for both
device-specific things and generic PCI things:
agp_nvidia_suspend
pci_save_state <-- generic PCI
pci_set_power_state(PCI_D3hot) <-- generic PCI
agp_nvidia_resume
pci_set_power_state(PCI_D0) <-- generic PCI
pci_restore_state <-- generic PCI
nvidia_configure <-- device-specific
Convert to generic power management where the PCI bus PM methods do the
generic PCI things, and the driver needs only the device-specific part,
i.e.,
suspend_devices_and_enter
dpm_suspend_start(PMSG_SUSPEND)
pci_pm_suspend # PCI bus .suspend() method
agp_nvidia_suspend <-- not needed at all; removed
suspend_enter
dpm_suspend_noirq(PMSG_SUSPEND)
pci_pm_suspend_noirq # PCI bus .suspend_noirq() method
pci_save_state <-- generic PCI
pci_prepare_to_sleep <-- generic PCI
pci_set_power_state
...
dpm_resume_end(PMSG_RESUME)
pci_pm_resume # PCI bus .resume() method
pci_restore_standard_config
pci_set_power_state(PCI_D0) <-- generic PCI
pci_restore_state <-- generic PCI
agp_nvidia_resume # driver->pm->resume
nvidia_configure <-- device-specific
Based on 0aeddbd0cb07 ("via-agp: convert to generic power management") by
Vaibhav Gupta <vaibhavgupta40@gmail.com>.
Link: https://lore.kernel.org/r/20221025203852.681822-6-helgaas@kernel.org
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Dave Airlie <airlied@redhat.com>
Convert agpgart-ati from legacy PCI power management to the generic power
management framework.
Previously agpgart-ati used legacy PCI power management, and
agp_ati_suspend() and agp_ati_resume() were responsible for both
device-specific things and generic PCI things like saving and restoring
config space and managing power state:
agp_ati_suspend
pci_save_state <-- generic PCI
pci_set_power_state(PCI_D3hot) <-- generic PCI
agp_ati_resume
pci_set_power_state(PCI_D0) <-- generic PCI
pci_restore_state <-- generic PCI
ati_configure <-- device-specific
With generic power management, the PCI bus PM methods do the generic PCI
things, and the driver needs only the device-specific part, i.e.,
suspend_devices_and_enter
dpm_suspend_start(PMSG_SUSPEND)
pci_pm_suspend # PCI bus .suspend() method
agp_ati_suspend <-- not needed at all; removed
suspend_enter
dpm_suspend_noirq(PMSG_SUSPEND)
pci_pm_suspend_noirq # PCI bus .suspend_noirq() method
pci_save_state <-- generic PCI
pci_prepare_to_sleep <-- generic PCI
pci_set_power_state
...
dpm_resume_end(PMSG_RESUME)
pci_pm_resume # PCI bus .resume() method
pci_restore_standard_config
pci_set_power_state(PCI_D0) <-- generic PCI
pci_restore_state <-- generic PCI
agp_ati_resume # driver->pm->resume
ati_configure <-- device-specific
Based on 0aeddbd0cb07 ("via-agp: convert to generic power management") by
Vaibhav Gupta <vaibhavgupta40@gmail.com>.
Link: https://lore.kernel.org/r/20221025203852.681822-5-helgaas@kernel.org
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Dave Airlie <airlied@redhat.com>
Convert agpgart-amdk7 from legacy PCI power management to the generic power
management framework.
Previously agpgart-amdk7 used legacy PCI power management, and
agp_amdk7_suspend() and agp_amdk7_resume() were responsible for both
device-specific things and generic PCI things like saving and restoring
config space and managing power state:
agp_amdk7_suspend
pci_save_state <-- generic PCI
pci_set_power_state <-- generic PCI
agp_amdk7_resume
pci_set_power_state(PCI_D0) <-- generic PCI
pci_restore_state <-- generic PCI
amd_irongate_driver.configure <-- device-specific
Convert to generic power management where the PCI bus PM methods do the
generic PCI things, and the driver needs only the device-specific part,
i.e.,
suspend_devices_and_enter
dpm_suspend_start(PMSG_SUSPEND)
pci_pm_suspend # PCI bus .suspend() method
agp_amdk7_suspend <-- not needed at all; removed
suspend_enter
dpm_suspend_noirq(PMSG_SUSPEND)
pci_pm_suspend_noirq # PCI bus .suspend_noirq() method
pci_save_state <-- generic PCI
pci_prepare_to_sleep <-- generic PCI
pci_set_power_state
...
dpm_resume_end(PMSG_RESUME)
pci_pm_resume # PCI bus .resume() method
pci_restore_standard_config
pci_set_power_state(PCI_D0) <-- generic PCI
pci_restore_state <-- generic PCI
agp_amdk7_resume # driver->pm->resume
amd_irongate_driver.configure <-- device-specific
Based on 0aeddbd0cb07 ("via-agp: convert to generic power management") by
Vaibhav Gupta <vaibhavgupta40@gmail.com>.
Link: https://lore.kernel.org/r/20221025203852.681822-4-helgaas@kernel.org
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Dave Airlie <airlied@redhat.com>
Convert agpgart-intel from legacy PCI power management to the generic power
management framework.
Previously agpgart-intel used legacy PCI power management, and
agp_intel_resume() was responsible for both device-specific things and
generic PCI things like saving and restoring config space and managing
power state.
In this case, agp_intel_suspend() was empty, and agp_intel_resume()
already did only device-specific things, so simply convert it to take a
struct device * instead of a struct pci_dev *.
Based on 0aeddbd0cb07 ("via-agp: convert to generic power management") by
Vaibhav Gupta <vaibhavgupta40@gmail.com>.
Link: https://lore.kernel.org/r/20221025203852.681822-3-helgaas@kernel.org
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Dave Airlie <airlied@redhat.com>
Convert agpgart-efficeon from legacy PCI power management to the generic
power management framework.
Previously agpgart-efficeon used legacy PCI power management, which means
agp_efficeon_suspend() and agp_efficeon_resume() were responsible for both
device-specific things and generic PCI things like saving and restoring
config space and managing power state.
In this case, agp_efficeon_suspend() was empty, and agp_efficeon_resume()
already did only device-specific things, so simply convert it to take a
struct device * instead of a struct pci_dev *.
Based on 0aeddbd0cb07 ("via-agp: convert to generic power management") by
Vaibhav Gupta <vaibhavgupta40@gmail.com>.
Link: https://lore.kernel.org/r/20221025203852.681822-2-helgaas@kernel.org
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Dave Airlie <airlied@redhat.com>
The current code provokes some kernel-doc warnings:
drivers/char/ipmi/ipmi_msghandler.c:618: warning: This comment starts with '/**', but isn't a kernel-doc comment. Refer Documentation/doc-guide/kernel-doc.rst
Signed-off-by: Bo Liu <liubo03@inspur.com>
Message-Id: <20221025060436.4372-1-liubo03@inspur.com>
Signed-off-by: Corey Minyard <cminyard@mvista.com>
This fixes the following sparse warning:
sparse warnings: (new ones prefixed by >>)
>> drivers/char/ipmi/ssif_bmc.c:254:22: sparse: sparse: invalid assignment: |=
>> drivers/char/ipmi/ssif_bmc.c:254:22: sparse: left side has type restricted __poll_t
>> drivers/char/ipmi/ssif_bmc.c:254:22: sparse: right side has type int
Fixes: dd2bc5cc9e25 ("ipmi: ssif_bmc: Add SSIF BMC driver")
Reported-by: kernel test robot <lkp@intel.com>
Link: https://lore.kernel.org/all/202210181103.ontD9tRT-lkp@intel.com/
Signed-off-by: Quan Nguyen <quan@os.amperecomputing.com>
Message-Id: <20221024075956.3312552-1-quan@os.amperecomputing.com>
Signed-off-by: Corey Minyard <cminyard@mvista.com>
The stm32_rng_read() function samples TRNG by 4 bytes until at
least 5 bytes are free in the input buffer. The last four bytes
are never read. For example, 60 bytes are returned in case the
input buffer size is 64 bytes.
Read until at least 4 bytes are free in the input buffer. Fill
the buffer entirely in case the buffer size is divisible by 4.
Cc: Oleg Karfich <oleg.karfich@wago.com>
Signed-off-by: Tomas Marek <tomas.marek@elrest.cz>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
The stm32_rng_read() function uses `retval` variable as a counter of
generated random bytes. However, the same variable is used to store
a result of the polling function in case the driver is waiting until
the TRNG is ready. The TRNG generates random numbers by 16B. One
loop read 4B. So, the function calls the polling every 16B, i.e.
every 4th loop. The `retval` counter is reset on poll call and only
number of bytes read after the last poll call is returned to the
caller. The remaining sampled random bytes (for example 48 out of
64 in case 64 bytes are read) are not used.
Use different variable to store the polling function result and
do not overwrite `retval` counter.
Cc: Oleg Karfich <oleg.karfich@wago.com>
Signed-off-by: Tomas Marek <tomas.marek@elrest.cz>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
1. Add trng compatible name for MT7986
2. Fix mtk_rng_wait_ready() function
Signed-off-by: Mingming.Su <Mingming.Su@mediatek.com>
Signed-off-by: Frank Wunderlich <frank-w@public-files.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Adding RNG NPCM8XX support to NPCM RNG driver.
RNG NPCM8XX uses a different clock prescaler.
As part of adding NPCM8XX support:
- Add NPCM8XX specific compatible string.
- Add data to handle architecture specific clock prescaler.
Signed-off-by: Tomer Maimon <tmaimon77@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
untrusted sources into /dev/random.
-----BEGIN PGP SIGNATURE-----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=qugm
-----END PGP SIGNATURE-----
Merge tag 'v6.1-p2' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6
Pull crypto fix from Herbert Xu:
"This fixes an issue exposed by the recent change to feed untrusted
sources into /dev/random"
* tag 'v6.1-p2' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6:
hwrng: bcm2835 - use hwrng_msleep() instead of cpu_relax()
If you continue to access and send messages at a high frequency (once
every 55s) when the IPMI is disconnected, messages will accumulate in
intf->[hp_]xmit_msg. If it lasts long enough, it takes up a lot of
memory.
The reason is that if IPMI is disconnected, each message will be set to
IDLE after it returns to HOSED through IDLE->ERROR0->HOSED. The next
message goes through the same process when it comes in. This process
needs to wait for IBF_TIMEOUT * (MAX_ERROR_RETRIES + 1) = 55s.
Each message takes 55S to destroy. This results in a continuous increase
in memory.
I find that if I wait 5 seconds after the first message fails, the
status changes to ERROR0 in smi_timeout(). The next message will return
the error code IPMI_NOT_IN_MY_STATE_ERR directly without wait.
This is more in line with our needs.
So instead of setting each message state to IDLE after it reaches the
state HOSED, set state to ERROR0.
After testing, the problem has been solved, no matter how many
consecutive sends, will not cause continuous memory growth. It also
returns to normal immediately after the IPMI is restored.
In addition, the HOSED state should also count as invalid. So the HOSED
is removed from the invalid judgment in start_kcs_transaction().
The verification operations are as follows:
1. Use BPF to record the ipmi_alloc/free_smi_msg().
$ bpftrace -e 'kretprobe:ipmi_alloc_recv_msg {printf("alloc
%p\n",retval);} kprobe:free_recv_msg {printf("free %p\n",arg0)}'
2. Exec `date; time for x in $(seq 1 2); do ipmitool mc info; done`.
3. Record the output of `time` and when free all msgs.
Before:
`time` takes 120s, This is because `ipmitool mc info` send 4 msgs and
waits only 15 seconds for each message. Last msg is free after 440s.
$ bpftrace -e 'kretprobe:ipmi_alloc_recv_msg {printf("alloc
%p\n",retval);} kprobe:free_recv_msg {printf("free %p\n",arg0)}'
Oct 05 11:40:55 Attaching 2 probes...
Oct 05 11:41:12 alloc 0xffff9558a05f0c00
Oct 05 11:41:27 alloc 0xffff9558a05f1a00
Oct 05 11:41:42 alloc 0xffff9558a05f0000
Oct 05 11:41:57 alloc 0xffff9558a05f1400
Oct 05 11:42:07 free 0xffff9558a05f0c00
Oct 05 11:42:07 alloc 0xffff9558a05f7000
Oct 05 11:42:22 alloc 0xffff9558a05f2a00
Oct 05 11:42:37 alloc 0xffff9558a05f5a00
Oct 05 11:42:52 alloc 0xffff9558a05f3a00
Oct 05 11:43:02 free 0xffff9558a05f1a00
Oct 05 11:43:57 free 0xffff9558a05f0000
Oct 05 11:44:52 free 0xffff9558a05f1400
Oct 05 11:45:47 free 0xffff9558a05f7000
Oct 05 11:46:42 free 0xffff9558a05f2a00
Oct 05 11:47:37 free 0xffff9558a05f5a00
Oct 05 11:48:32 free 0xffff9558a05f3a00
$ root@dc00-pb003-t106-n078:~# date;time for x in $(seq 1 2); do
ipmitool mc info; done
Wed Oct 5 11:41:12 CST 2022
No data available
Get Device ID command failed
No data available
No data available
No valid response received
Get Device ID command failed: Unspecified error
No data available
Get Device ID command failed
No data available
No data available
No valid response received
No data available
Get Device ID command failed
real 1m55.052s
user 0m0.001s
sys 0m0.001s
After:
`time` takes 55s, all msgs is returned and free after 55s.
$ bpftrace -e 'kretprobe:ipmi_alloc_recv_msg {printf("alloc
%p\n",retval);} kprobe:free_recv_msg {printf("free %p\n",arg0)}'
Oct 07 16:30:35 Attaching 2 probes...
Oct 07 16:30:45 alloc 0xffff955943aa9800
Oct 07 16:31:00 alloc 0xffff955943aacc00
Oct 07 16:31:15 alloc 0xffff955943aa8c00
Oct 07 16:31:30 alloc 0xffff955943aaf600
Oct 07 16:31:40 free 0xffff955943aa9800
Oct 07 16:31:40 free 0xffff955943aacc00
Oct 07 16:31:40 free 0xffff955943aa8c00
Oct 07 16:31:40 free 0xffff955943aaf600
Oct 07 16:31:40 alloc 0xffff9558ec8f7e00
Oct 07 16:31:40 free 0xffff9558ec8f7e00
Oct 07 16:31:40 alloc 0xffff9558ec8f7800
Oct 07 16:31:40 free 0xffff9558ec8f7800
Oct 07 16:31:40 alloc 0xffff9558ec8f7e00
Oct 07 16:31:40 free 0xffff9558ec8f7e00
Oct 07 16:31:40 alloc 0xffff9558ec8f7800
Oct 07 16:31:40 free 0xffff9558ec8f7800
root@dc00-pb003-t106-n078:~# date;time for x in $(seq 1 2); do
ipmitool mc info; done
Fri Oct 7 16:30:45 CST 2022
No data available
Get Device ID command failed
No data available
No data available
No valid response received
Get Device ID command failed: Unspecified error
Get Device ID command failed: 0xd5 Command not supported in present state
Get Device ID command failed: Command not supported in present state
real 0m55.038s
user 0m0.001s
sys 0m0.001s
Signed-off-by: Zhang Yuchen <zhangyuchen.lcr@bytedance.com>
Message-Id: <20221009091811.40240-2-zhangyuchen.lcr@bytedance.com>
Signed-off-by: Corey Minyard <cminyard@mvista.com>
After the IPMI disconnect problem, the memory kept rising and we tried
to unload the driver to free the memory. However, only part of the
free memory is recovered after the driver is uninstalled. Using
ebpf to hook free functions, we find that neither ipmi_user nor
ipmi_smi_msg is free, only ipmi_recv_msg is free.
We find that the deliver_smi_err_response call in clean_smi_msgs does
the destroy processing on each message from the xmit_msg queue without
checking the return value and free ipmi_smi_msg.
deliver_smi_err_response is called only at this location. Adding the
free handling has no effect.
To verify, try using ebpf to trace the free function.
$ bpftrace -e 'kretprobe:ipmi_alloc_recv_msg {printf("alloc rcv
%p\n",retval);} kprobe:free_recv_msg {printf("free recv %p\n",
arg0)} kretprobe:ipmi_alloc_smi_msg {printf("alloc smi %p\n",
retval);} kprobe:free_smi_msg {printf("free smi %p\n",arg0)}'
Signed-off-by: Zhang Yuchen <zhangyuchen.lcr@bytedance.com>
Message-Id: <20221007092617.87597-4-zhangyuchen.lcr@bytedance.com>
[Fixed the comment above handle_one_recv_msg().]
Signed-off-by: Corey Minyard <cminyard@mvista.com>
When fixing the problem mentioned in PATCH1, we also found
the following problem:
If the IPMI is disconnected and in the sending process, the
uninstallation driver will be stuck for a long time.
The main problem is that uninstalling the driver waits for curr_msg to
be sent or HOSED. After stopping tasklet, the only place to trigger the
timeout mechanism is the circular poll in shutdown_smi.
The poll function delays 10us and calls smi_event_handler(smi_info,10).
Smi_event_handler deducts 10us from kcs->ibf_timeout.
But the poll func is followed by schedule_timeout_uninterruptible(1).
The time consumed here is not counted in kcs->ibf_timeout.
So when 10us is deducted from kcs->ibf_timeout, at least 1 jiffies has
actually passed. The waiting time has increased by more than a
hundredfold.
Now instead of calling poll(). call smi_event_handler() directly and
calculate the elapsed time.
For verification, you can directly use ebpf to check the kcs->
ibf_timeout for each call to kcs_event() when IPMI is disconnected.
Decrement at normal rate before unloading. The decrement rate becomes
very slow after unloading.
$ bpftrace -e 'kprobe:kcs_event {printf("kcs->ibftimeout : %d\n",
*(arg0+584));}'
Signed-off-by: Zhang Yuchen <zhangyuchen.lcr@bytedance.com>
Message-Id: <20221007092617.87597-3-zhangyuchen.lcr@bytedance.com>
Signed-off-by: Corey Minyard <cminyard@mvista.com>
Cc: stable@vger.kernel.org
The ASPEED KCS devices don't provide a BMC-side interrupt for the host
reading the output data register (ODR). The act of the host reading ODR
clears the output buffer full (OBF) flag in the status register (STR),
informing the BMC it can transmit a subsequent byte.
On the BMC side the KCS client must enable the OBE event *and* perform a
subsequent read of STR anyway to avoid races - the polling provides a
window for the host to read ODR if data was freshly written while
minimising BMC-side latency.
Fixes: 28651e6c4237 ("ipmi: kcs_bmc: Allow clients to control KCS IRQ state")
Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
Reviewed-by: Joel Stanley <joel@jms.id.au>
Message-Id: <20220812144741.240315-1-andrew@aj.id.au>
Signed-off-by: Corey Minyard <cminyard@mvista.com>
The SMBus system interface (SSIF) IPMI BMC driver can be used to perform
in-band IPMI communication with their host in management (BMC) side.
Thanks Dan for the copy_from_user() fix in the link below.
Link: https://lore.kernel.org/linux-arm-kernel/20220310114119.13736-4-quan@os.amperecomputing.com/
Signed-off-by: Quan Nguyen <quan@os.amperecomputing.com>
Message-Id: <20221004093106.1653317-2-quan@os.amperecomputing.com>
Signed-off-by: Corey Minyard <cminyard@mvista.com>
With no callers left of prandom_u32() and prandom_bytes(), as well as
get_random_int(), remove these deprecated wrappers, in favor of
get_random_u32() and get_random_bytes().
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Yury Norov <yury.norov@gmail.com>
Acked-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
This is mostly just doc, config, and little tweaks. Nothing big, which
is why there was nothing for 6.0. There is one crash fix, but it's not
something that I think anyone is using yet.
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Merge tag 'for-linus-6.1-1' of https://github.com/cminyard/linux-ipmi
Pull IPMI updates from Corey Minyard:
"Fix a bunch of little problems in IPMI
This is mostly just doc, config, and little tweaks. Nothing big, which
is why there was nothing for 6.0. There is one crash fix, but it's not
something that I think anyone is using yet"
* tag 'for-linus-6.1-1' of https://github.com/cminyard/linux-ipmi:
ipmi: Remove unused struct watcher_entry
ipmi: kcs: aspeed: Update port address comments
ipmi: Add __init/__exit annotations to module init/exit funcs
ipmi:ipmb: Don't call ipmi_unregister_smi() on a register failure
ipmi:ipmb: Fix a vague comment and a typo
dt-binding: ipmi: add fallback to npcm845 compatible
ipmi: Fix comment typo
char: ipmi: modify NPCM KCS configuration
dt-bindings: ipmi: Add npcm845 compatible
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Merge tag 'tpmdd-next-v6.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jarkko/linux-tpmdd
Pull tpm updates from Jarkko Sakkinen:
"Just a few bug fixes this time"
* tag 'tpmdd-next-v6.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jarkko/linux-tpmdd:
selftest: tpm2: Add Client.__del__() to close /dev/tpm* handle
security/keys: Remove inconsistent __user annotation
char: move from strlcpy with unused retval to strscpy
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Merge tag 'random-6.1-rc1-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/crng/random
Pull random number generator updates from Jason Donenfeld:
- Huawei reported that when they updated their kernel from 4.4 to
something much newer, some userspace code they had broke, the culprit
being the accidental removal of O_NONBLOCK from /dev/random way back
in 5.6. It's been gone for over 2 years now and this is the first
we've heard of it, but userspace breakage is userspace breakage, so
O_NONBLOCK is now back.
- Use randomness from hardware RNGs much more often during early boot,
at the same interval that crng reseeds are done, from Dominik.
- A semantic change in hardware RNG throttling, so that the hwrng
framework can properly feed random.c with randomness from hardware
RNGs that aren't specifically marked as creditable.
A related patch coming to you via Herbert's hwrng tree depends on
this one, not to compile, but just to function properly, so you may
want to merge this PULL before that one.
- A fix to clamp credited bits from the interrupts pool to the size of
the pool sample. This is mainly just a theoretical fix, as it'd be
pretty hard to exceed it in practice.
- Oracle reported that InfiniBand TCP latency regressed by around
10-15% after a change a few cycles ago made at the request of the RT
folks, in which we hoisted a somewhat rare operation (1 in 1024
times) out of the hard IRQ handler and into a workqueue, a pretty
common and boring pattern.
It turns out, though, that scheduling a worker from there has
overhead of its own, whereas scheduling a timer on that same CPU for
the next jiffy amortizes better and doesn't incur the same overhead.
I also eliminated a cache miss by moving the work_struct (and
subsequently, the timer_list) to below a critical cache line, so that
the more critical members that are accessed on every hard IRQ aren't
split between two cache lines.
- The boot-time initialization of the RNG has been split into two
approximate phases: what we can accomplish before timekeeping is
possible and what we can accomplish after.
This winds up being useful so that we can use RDRAND to seed the RNG
before CONFIG_SLAB_FREELIST_RANDOM=y systems initialize slabs, in
addition to other early uses of randomness. The effect is that
systems with RDRAND (or a bootloader seed) will never see any
warnings at all when setting CONFIG_WARN_ALL_UNSEEDED_RANDOM=y. And
kfence benefits from getting a better seed of its own.
- Small systems without much entropy sometimes wind up putting some
truncated serial number read from flash into hostname, so contribute
utsname changes to the RNG, without crediting.
- Add smaller batches to serve requests for smaller integers, and make
use of them when people ask for random numbers bounded by a given
compile-time constant. This has positive effects all over the tree,
most notably in networking and kfence.
- The original jitter algorithm intended (I believe) to schedule the
timer for the next jiffy, not the next-next jiffy, yet it used
mod_timer(jiffies + 1), which will fire on the next-next jiffy,
instead of what I believe was intended, mod_timer(jiffies), which
will fire on the next jiffy. So fix that.
- Fix a comment typo, from William.
* tag 'random-6.1-rc1-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/crng/random:
random: clear new batches when bringing new CPUs online
random: fix typos in get_random_bytes() comment
random: schedule jitter credit for next jiffy, not in two jiffies
prandom: make use of smaller types in prandom_u32_max
random: add 8-bit and 16-bit batches
utsname: contribute changes to RNG
random: use init_utsname() instead of utsname()
kfence: use better stack hash seed
random: split initialization into early step and later step
random: use expired timer rather than wq for mixing fast pool
random: avoid reading two cache lines on irq randomness
random: clamp credited irq bits to maximum mixed
random: throttle hwrng writes if no entropy is credited
random: use hwgenerator randomness more frequently at early boot
random: restore O_NONBLOCK support
Here is the big set of TTY and Serial driver updates for 6.1-rc1.
Lots of cleanups in here, no real new functionality this time around,
with the diffstat being that we removed more lines than we added!
Included in here are:
- termios unification cleanups from Al Viro, it's nice to
finally get this work done
- tty serial transmit cleanups in various drivers in preparation
for more cleanup and unification in future releases (that work
was not ready for this release.)
- n_gsm fixes and updates
- ktermios cleanups and code reductions
- dt bindings json conversions and updates for new devices
- some serial driver updates for new devices
- lots of other tiny cleanups and janitorial stuff. Full
details in the shortlog.
All of these have been in linux-next for a while with no reported
issues.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'tty-6.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty
Pull tty/serial driver updates from Greg KH:
"Here is the big set of TTY and Serial driver updates for 6.1-rc1.
Lots of cleanups in here, no real new functionality this time around,
with the diffstat being that we removed more lines than we added!
Included in here are:
- termios unification cleanups from Al Viro, it's nice to finally get
this work done
- tty serial transmit cleanups in various drivers in preparation for
more cleanup and unification in future releases (that work was not
ready for this release)
- n_gsm fixes and updates
- ktermios cleanups and code reductions
- dt bindings json conversions and updates for new devices
- some serial driver updates for new devices
- lots of other tiny cleanups and janitorial stuff. Full details in
the shortlog.
All of these have been in linux-next for a while with no reported
issues"
* tag 'tty-6.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (102 commits)
serial: cpm_uart: Don't request IRQ too early for console port
tty: serial: do unlock on a common path in altera_jtaguart_console_putc()
tty: serial: unify TX space reads under altera_jtaguart_tx_space()
tty: serial: use FIELD_GET() in lqasc_tx_ready()
tty: serial: extend lqasc_tx_ready() to lqasc_console_putchar()
tty: serial: allow pxa.c to be COMPILE_TESTed
serial: stm32: Fix unused-variable warning
tty: serial: atmel: Add COMMON_CLK dependency to SERIAL_ATMEL
serial: 8250: Fix restoring termios speed after suspend
serial: Deassert Transmit Enable on probe in driver-specific way
serial: 8250_dma: Convert to use uart_xmit_advance()
serial: 8250_omap: Convert to use uart_xmit_advance()
MAINTAINERS: Solve warning regarding inexistent atmel-usart binding
serial: stm32: Deassert Transmit Enable on ->rs485_config()
serial: ar933x: Deassert Transmit Enable on ->rs485_config()
tty: serial: atmel: Use FIELD_PREP/FIELD_GET
tty: serial: atmel: Make the driver aware of the existence of GCLK
tty: serial: atmel: Only divide Clock Divisor if the IP is USART
tty: serial: atmel: Separate mode clearing between UART and USART
dt-bindings: serial: atmel,at91-usart: Add gclk as a possible USART clock
...
The commit that added the new get_random_{u8,u16}() functions neglected
to update the code that clears the batches when bringing up a new CPU.
It also forgot a few comments and helper defines, so add those in too.
Fixes: 585cd5fe9f73 ("random: add 8-bit and 16-bit batches")
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Follow the advice of the below link and prefer 'strscpy' in this
subsystem. Conversion is 1:1 because the return value is not used.
Generated by a coccinelle script.
Link: https://lore.kernel.org/r/CAHk-=wgfRnXz0W3D37d01q3JFkr_i_uTL=V6A6G1oUZcprmknw@mail.gmail.com/
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
Remove extra whitespace and add a missing word to a sentence describing
get_random_bytes().
Signed-off-by: William Zijl <postmaster@gusted.xyz>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Counterintuitively, mod_timer(..., jiffies + 1) will cause the timer to
fire not in the next jiffy, but in two jiffies. The way to cause
the timer to fire in the next jiffy is with mod_timer(..., jiffies).
Doing so then lets us bump the upper bound back up again.
Fixes: 50ee7529ec45 ("random: try to actively add entropy rather than passively wait for it")
Fixes: 829d680e82a9 ("random: cap jitter samples per bit to factor of HZ")
Cc: Dominik Brodowski <linux@dominikbrodowski.net>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Sultan Alsawaf <sultan@kerneltoast.com>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Start the hwrng kthread even if the hwrng source has a quality setting
of zero. Then, every crng reseed interval, one batch of data from this
zero-quality hwrng source will be mixed into the CRNG pool.
This patch is based on the assumption that data from a hwrng source
will not actively harm the CRNG state. Instead, many hwrng sources
(such as TPM devices), even though they are assigend a quality level of
zero, actually provide some entropy, which is good enough to mix into
the CRNG pool every once in a while.
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
There are numerous places in the kernel that would be sped up by having
smaller batches. Currently those callsites do `get_random_u32() & 0xff`
or similar. Since these are pretty spread out, and will require patches
to multiple different trees, let's get ahead of the curve and lay the
foundation for `get_random_u8()` and `get_random_u16()`, so that it's
then possible to start submitting conversion patches leisurely.
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Rather than going through the current-> indirection for utsname, at this
point in boot, init_utsname()==utsname(), so just use it directly that
way. Additionally, init_utsname() appears to be available nearly always,
so move it into random_init_early().
Suggested-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
The full RNG initialization relies on some timestamps, made possible
with initialization functions like time_init() and timekeeping_init().
However, these are only available rather late in initialization.
Meanwhile, other things, such as memory allocator functions, make use of
the RNG much earlier.
So split RNG initialization into two phases. We can provide arch
randomness very early on, and then later, after timekeeping and such are
available, initialize the rest.
This ensures that, for example, slabs are properly randomized if RDRAND
is available. Without this, CONFIG_SLAB_FREELIST_RANDOM=y loses a degree
of its security, because its random seed is potentially deterministic,
since it hasn't yet incorporated RDRAND. It also makes it possible to
use a better seed in kfence, which currently relies on only the cycle
counter.
Another positive consequence is that on systems with RDRAND, running
with CONFIG_WARN_ALL_UNSEEDED_RANDOM=y results in no warnings at all.
One subtle side effect of this change is that on systems with no RDRAND,
RDTSC is now only queried by random_init() once, committing the moment
of the function call, instead of multiple times as before. This is
intentional, as the multiple RDTSCs in a loop before weren't
accomplishing very much, with jitter being better provided by
try_to_generate_entropy(). Plus, filling blocks with RDTSC is still
being done in extract_entropy(), which is necessarily called before
random bytes are served anyway.
Cc: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Previously, the fast pool was dumped into the main pool periodically in
the fast pool's hard IRQ handler. This worked fine and there weren't
problems with it, until RT came around. Since RT converts spinlocks into
sleeping locks, problems cropped up. Rather than switching to raw
spinlocks, the RT developers preferred we make the transformation from
originally doing:
do_some_stuff()
spin_lock()
do_some_other_stuff()
spin_unlock()
to doing:
do_some_stuff()
queue_work_on(some_other_stuff_worker)
This is an ordinary pattern done all over the kernel. However, Sherry
noticed a 10% performance regression in qperf TCP over a 40gbps
InfiniBand card. Quoting her message:
> MT27500 Family [ConnectX-3] cards:
> Infiniband device 'mlx4_0' port 1 status:
> default gid: fe80:0000:0000:0000:0010:e000:0178:9eb1
> base lid: 0x6
> sm lid: 0x1
> state: 4: ACTIVE
> phys state: 5: LinkUp
> rate: 40 Gb/sec (4X QDR)
> link_layer: InfiniBand
>
> Cards are configured with IP addresses on private subnet for IPoIB
> performance testing.
> Regression identified in this bug is in TCP latency in this stack as reported
> by qperf tcp_lat metric:
>
> We have one system listen as a qperf server:
> [root@yourQperfServer ~]# qperf
>
> Have the other system connect to qperf server as a client (in this
> case, it’s X7 server with Mellanox card):
> [root@yourQperfClient ~]# numactl -m0 -N0 qperf 20.20.20.101 -v -uu -ub --time 60 --wait_server 20 -oo msg_size:4K:1024K:*2 tcp_lat
Rather than incur the scheduling latency from queue_work_on, we can
instead switch to running on the next timer tick, on the same core. This
also batches things a bit more -- once per jiffy -- which is okay now
that mix_interrupt_randomness() can credit multiple bits at once.
Reported-by: Sherry Yang <sherry.yang@oracle.com>
Tested-by: Paul Webb <paul.x.webb@oracle.com>
Cc: Sherry Yang <sherry.yang@oracle.com>
Cc: Phillip Goerl <phillip.goerl@oracle.com>
Cc: Jack Vogel <jack.vogel@oracle.com>
Cc: Nicky Veitch <nicky.veitch@oracle.com>
Cc: Colm Harrington <colm.harrington@oracle.com>
Cc: Ramanan Govindarajan <ramanan.govindarajan@oracle.com>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Dominik Brodowski <linux@dominikbrodowski.net>
Cc: Tejun Heo <tj@kernel.org>
Cc: Sultan Alsawaf <sultan@kerneltoast.com>
Cc: stable@vger.kernel.org
Fixes: 58340f8e952b ("random: defer fast pool mixing to worker")
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
In order to avoid reading and dirtying two cache lines on every IRQ,
move the work_struct to the bottom of the fast_pool struct. add_
interrupt_randomness() always touches .pool and .count, which are
currently split, because .mix pushes everything down. Instead, move .mix
to the bottom, so that .pool and .count are always in the first cache
line, since .mix is only accessed when the pool is full.
Fixes: 58340f8e952b ("random: defer fast pool mixing to worker")
Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
After commit e86ee2d44b44("ipmi: Rework locking and shutdown for hot remove"),
no one use struct watcher_entry, so remove it.
Signed-off-by: Yuan Can <yuancan@huawei.com>
Message-Id: <20220927133814.98929-1-yuancan@huawei.com>
Signed-off-by: Corey Minyard <cminyard@mvista.com>
Since the most that's mixed into the pool is sizeof(long)*2, don't
credit more than that many bytes of entropy.
Fixes: e3e33fc2ea7f ("random: do not use input pool from hard IRQs")
Cc: stable@vger.kernel.org
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
If a hwrng source does not provide an entropy estimate, it currently
does not contribute at all to the CRNG. In order to help fix this, in
case add_hwgenerator_randomness() is called with the entropy parameter
set to zero, go to sleep until one reseed interval has passed.
While the hwrng thread currently only runs under conditions where this
is non-zero, this change is not harmful and prepares for future updates
to the hwrng core.
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Mix in randomness from hw-rng sources more frequently during early
boot, approximately once for every rng reseed.
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Prior to 5.6, when /dev/random was opened with O_NONBLOCK, it would
return -EAGAIN if there was no entropy. When the pools were unified in
5.6, this was lost. The post 5.6 behavior of blocking until the pool is
initialized, and ignoring O_NONBLOCK in the process, went unnoticed,
with no reports about the regression received for two and a half years.
However, eventually this indeed did break somebody's userspace.
So we restore the old behavior, by returning -EAGAIN if the pool is not
initialized. Unlike the old /dev/random, this can only occur during
early boot, after which it never blocks again.
In order to make this O_NONBLOCK behavior consistent with other
expectations, also respect users reading with preadv2(RWF_NOWAIT) and
similar.
Fixes: 30c08efec888 ("random: make /dev/random be almost like /dev/urandom")
Reported-by: Guozihua <guozihua@huawei.com>
Reported-by: Zhongguohua <zhongguohua1@huawei.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Andrew Lutomirski <luto@kernel.org>
Cc: stable@vger.kernel.org
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Remove AST_usrGuide_KCS.pdf as it is no longer maintained.
Add more descriptions as the driver now supports the I/O
address configurations for both the KCS Data and Cmd/Status
interface registers.
Signed-off-by: Chia-Wei Wang <chiawei_wang@aspeedtech.com>
Message-Id: <20220920020333.601-1-chiawei_wang@aspeedtech.com>
[I don't like removing documentation, but the document in question
was a personal note by an employee and nothing official and not
necessarily guaranteed to be accurate in the future. So go
ahead and remove it.]
Signed-off-by: Corey Minyard <cminyard@mvista.com>
