docs: Update documentation to reflect what TAINT_CPU_OUT_OF_SPEC means

Here's a patch updating the meaning of TAINT_CPU_OUT_OF_SPEC after
Borislav introduced changes in a7e1f67ed2 and upcoming patches in tip.

TAINT_CPU_OUT_OF_SPEC now means a bit more what it implies as the
flag isn't set just because of a CPU misconfiguration or mismatch.
Historically it was for SMP kernel oops on an officially SMP incapable
processor but now it also covers CPUs whose MSRs have been incorrectly
poked at from userspace, drivers being used on non supported
architectures, broken firmware, mismatched CPUs, ...

Update documentation and script to reflect that.

Signed-off-by: Mathieu Chouquet-Stringer <me@mathieu.digital>
Link: https://lore.kernel.org/r/20201202153244.709752-1-me@mathieu.digital
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
This commit is contained in:
Mathieu Chouquet-Stringer 2020-12-02 16:32:43 +01:00 committed by Jonathan Corbet
parent 907d1f143b
commit 547f574fd9
3 changed files with 20 additions and 7 deletions

View File

@ -1336,7 +1336,7 @@ ORed together. The letters are seen in "Tainted" line of Oops reports.
====== ===== ==============================================================
1 `(P)` proprietary module was loaded
2 `(F)` module was force loaded
4 `(S)` SMP kernel oops on an officially SMP incapable processor
4 `(S)` kernel running on an out of specification system
8 `(R)` module was force unloaded
16 `(M)` processor reported a Machine Check Exception (MCE)
32 `(B)` bad page referenced or some unexpected page flags

View File

@ -84,7 +84,7 @@ Bit Log Number Reason that got the kernel tainted
=== === ====== ========================================================
0 G/P 1 proprietary module was loaded
1 _/F 2 module was force loaded
2 _/S 4 SMP kernel oops on an officially SMP incapable processor
2 _/S 4 kernel running on an out of specification system
3 _/R 8 module was force unloaded
4 _/M 16 processor reported a Machine Check Exception (MCE)
5 _/B 32 bad page referenced or some unexpected page flags
@ -116,10 +116,23 @@ More detailed explanation for tainting
1) ``F`` if any module was force loaded by ``insmod -f``, ``' '`` if all
modules were loaded normally.
2) ``S`` if the oops occurred on an SMP kernel running on hardware that
hasn't been certified as safe to run multiprocessor.
Currently this occurs only on various Athlons that are not
SMP capable.
2) ``S`` if the kernel is running on a processor or system that is out of
specification: hardware has been put into an unsupported configuration,
therefore proper execution cannot be guaranteed.
Kernel will be tainted if, for example:
- on x86: PAE is forced through forcepae on intel CPUs (such as Pentium M)
which do not report PAE but may have a functional implementation, an SMP
kernel is running on non officially capable SMP Athlon CPUs, MSRs are
being poked at from userspace.
- on arm: kernel running on certain CPUs (such as Keystone 2) without
having certain kernel features enabled.
- on arm64: there are mismatched hardware features between CPUs, the
bootloader has booted CPUs in different modes.
- certain drivers are being used on non supported architectures (such as
scsi/snic on something else than x86_64, scsi/ips on non
x86/x86_64/itanium, have broken firmware settings for the
irqchip/irq-gic on arm64 ...).
3) ``R`` if a module was force unloaded by ``rmmod -f``, ``' '`` if all
modules were unloaded normally.

View File

@ -72,7 +72,7 @@ if [ `expr $T % 2` -eq 0 ]; then
addout " "
else
addout "S"
echo " * SMP kernel oops on an officially SMP incapable processor (#2)"
echo " * kernel running on an out of specification system (#2)"
fi
T=`expr $T / 2`