<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux.git/arch, branch v5.4.302</title>
<subtitle>Clone of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git</subtitle>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/'/>
<entry>
<title>MIPS: Malta: Fix !EVA SOC-it PCI MMIO</title>
<updated>2025-12-03T11:45:20+00:00</updated>
<author>
<name>Maciej W. Rozycki</name>
<email>macro@orcam.me.uk</email>
</author>
<published>2025-10-20T01:11:49+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=1c74ded6a18a3030f327dc2f497dd9da3adfbc1a'/>
<id>1c74ded6a18a3030f327dc2f497dd9da3adfbc1a</id>
<content type='text'>
commit ebd729fef31620e0bf74cbf8a4c7fda73a2a4e7e upstream.

Fix a regression that has caused accesses to the PCI MMIO window to
complete unclaimed in non-EVA configurations with the SOC-it family of
system controllers, preventing PCI devices from working that use MMIO.

In the non-EVA case PHYS_OFFSET is set to 0, meaning that PCI_BAR0 is
set with an empty mask (and PCI_HEAD4 matches addresses starting from 0
accordingly).  Consequently all addresses are matched for incoming DMA
accesses from PCI.  This seems to confuse the system controller's logic
and outgoing bus cycles targeting the PCI MMIO window seem not to make
it to the intended devices.

This happens as well when a wider mask is used with PCI_BAR0, such as
0x80000000 or 0xe0000000, that makes addresses match that overlap with
the PCI MMIO window, which starts at 0x10000000 in our configuration.

Set the mask in PCI_BAR0 to 0xf0000000 for non-EVA then, covering the
non-EVA maximum 256 MiB of RAM, which is what YAMON does and which used
to work correctly up to the offending commit.  Set PCI_P2SCMSKL to match
PCI_BAR0 as required by the system controller's specification, and match
PCI_P2SCMAPL to PCI_HEAD4 for identity mapping.

Verified with:

Core board type/revision =      0x0d (Core74K) / 0x01
System controller/revision =    MIPS SOC-it 101 OCP / 1.3   SDR-FW-4:1
Processor Company ID/options =  0x01 (MIPS Technologies, Inc.) / 0x1c
Processor ID/revision =         0x97 (MIPS 74Kf) / 0x4c

for non-EVA and with:

Core board type/revision =      0x0c (CoreFPGA-5) / 0x00
System controller/revision =    MIPS ROC-it2 / 0.0   FW-1:1 (CLK_unknown) GIC
Processor Company ID/options =  0x01 (MIPS Technologies, Inc.) / 0x00
Processor ID/revision =         0xa0 (MIPS interAptiv UP) / 0x20

for EVA/non-EVA, fixing:

defxx 0000:00:12.0: assign IRQ: got 10
defxx: v1.12 2021/03/10  Lawrence V. Stefani and others
0000:00:12.0: Could not read adapter factory MAC address!

vs:

defxx 0000:00:12.0: assign IRQ: got 10
defxx: v1.12 2021/03/10  Lawrence V. Stefani and others
0000:00:12.0: DEFPA at MMIO addr = 0x10142000, IRQ = 10, Hardware addr = 00-00-f8-xx-xx-xx
0000:00:12.0: registered as fddi0

for non-EVA and causing no change for EVA.

Signed-off-by: Maciej W. Rozycki &lt;macro@orcam.me.uk&gt;
Fixes: 422dd256642b ("MIPS: Malta: Allow PCI devices DMA to lower 2GB physical")
Cc: stable@vger.kernel.org # v4.9+
Signed-off-by: Thomas Bogendoerfer &lt;tsbogend@alpha.franken.de&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit ebd729fef31620e0bf74cbf8a4c7fda73a2a4e7e upstream.

Fix a regression that has caused accesses to the PCI MMIO window to
complete unclaimed in non-EVA configurations with the SOC-it family of
system controllers, preventing PCI devices from working that use MMIO.

In the non-EVA case PHYS_OFFSET is set to 0, meaning that PCI_BAR0 is
set with an empty mask (and PCI_HEAD4 matches addresses starting from 0
accordingly).  Consequently all addresses are matched for incoming DMA
accesses from PCI.  This seems to confuse the system controller's logic
and outgoing bus cycles targeting the PCI MMIO window seem not to make
it to the intended devices.

This happens as well when a wider mask is used with PCI_BAR0, such as
0x80000000 or 0xe0000000, that makes addresses match that overlap with
the PCI MMIO window, which starts at 0x10000000 in our configuration.

Set the mask in PCI_BAR0 to 0xf0000000 for non-EVA then, covering the
non-EVA maximum 256 MiB of RAM, which is what YAMON does and which used
to work correctly up to the offending commit.  Set PCI_P2SCMSKL to match
PCI_BAR0 as required by the system controller's specification, and match
PCI_P2SCMAPL to PCI_HEAD4 for identity mapping.

Verified with:

Core board type/revision =      0x0d (Core74K) / 0x01
System controller/revision =    MIPS SOC-it 101 OCP / 1.3   SDR-FW-4:1
Processor Company ID/options =  0x01 (MIPS Technologies, Inc.) / 0x1c
Processor ID/revision =         0x97 (MIPS 74Kf) / 0x4c

for non-EVA and with:

Core board type/revision =      0x0c (CoreFPGA-5) / 0x00
System controller/revision =    MIPS ROC-it2 / 0.0   FW-1:1 (CLK_unknown) GIC
Processor Company ID/options =  0x01 (MIPS Technologies, Inc.) / 0x00
Processor ID/revision =         0xa0 (MIPS interAptiv UP) / 0x20

for EVA/non-EVA, fixing:

defxx 0000:00:12.0: assign IRQ: got 10
defxx: v1.12 2021/03/10  Lawrence V. Stefani and others
0000:00:12.0: Could not read adapter factory MAC address!

vs:

defxx 0000:00:12.0: assign IRQ: got 10
defxx: v1.12 2021/03/10  Lawrence V. Stefani and others
0000:00:12.0: DEFPA at MMIO addr = 0x10142000, IRQ = 10, Hardware addr = 00-00-f8-xx-xx-xx
0000:00:12.0: registered as fddi0

for non-EVA and causing no change for EVA.

Signed-off-by: Maciej W. Rozycki &lt;macro@orcam.me.uk&gt;
Fixes: 422dd256642b ("MIPS: Malta: Allow PCI devices DMA to lower 2GB physical")
Cc: stable@vger.kernel.org # v4.9+
Signed-off-by: Thomas Bogendoerfer &lt;tsbogend@alpha.franken.de&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>sparc/module: Add R_SPARC_UA64 relocation handling</title>
<updated>2025-12-03T11:45:13+00:00</updated>
<author>
<name>Koakuma</name>
<email>koachan@protonmail.com</email>
</author>
<published>2025-06-09T13:53:11+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=0c38d95aa2ba7b10663c70c009023e43918a5429'/>
<id>0c38d95aa2ba7b10663c70c009023e43918a5429</id>
<content type='text'>
[ Upstream commit 05457d96175d25c976ab6241c332ae2eb5e07833 ]

This is needed so that the kernel can handle R_SPARC_UA64 relocations,
which is emitted by LLVM's IAS.

Signed-off-by: Koakuma &lt;koachan@protonmail.com&gt;
Reviewed-by: Andreas Larsson &lt;andreas@gaisler.com&gt;
Signed-off-by: Andreas Larsson &lt;andreas@gaisler.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 05457d96175d25c976ab6241c332ae2eb5e07833 ]

This is needed so that the kernel can handle R_SPARC_UA64 relocations,
which is emitted by LLVM's IAS.

Signed-off-by: Koakuma &lt;koachan@protonmail.com&gt;
Reviewed-by: Andreas Larsson &lt;andreas@gaisler.com&gt;
Signed-off-by: Andreas Larsson &lt;andreas@gaisler.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>mips: lantiq: xway: sysctrl: rename stp clock</title>
<updated>2025-12-03T11:45:11+00:00</updated>
<author>
<name>Aleksander Jan Bajkowski</name>
<email>olek2@wp.pl</email>
</author>
<published>2025-08-15T12:12:23+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=30928ea5f75ae62e8d4cfcf5390f7cf961c1bd81'/>
<id>30928ea5f75ae62e8d4cfcf5390f7cf961c1bd81</id>
<content type='text'>
[ Upstream commit b0d04fe6a633ada2c7bc1b5ddd011cbd85961868 ]

Bindig requires a node name matching ‘^gpio@[0-9a-f]+$’. This patch
changes the clock name from “stp” to “gpio”.

Signed-off-by: Aleksander Jan Bajkowski &lt;olek2@wp.pl&gt;
Signed-off-by: Thomas Bogendoerfer &lt;tsbogend@alpha.franken.de&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit b0d04fe6a633ada2c7bc1b5ddd011cbd85961868 ]

Bindig requires a node name matching ‘^gpio@[0-9a-f]+$’. This patch
changes the clock name from “stp” to “gpio”.

Signed-off-by: Aleksander Jan Bajkowski &lt;olek2@wp.pl&gt;
Signed-off-by: Thomas Bogendoerfer &lt;tsbogend@alpha.franken.de&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>mips: lantiq: danube: add missing device_type in pci node</title>
<updated>2025-12-03T11:45:10+00:00</updated>
<author>
<name>Aleksander Jan Bajkowski</name>
<email>olek2@wp.pl</email>
</author>
<published>2025-08-11T13:34:13+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=9da5dddafcbb1801b34dfdc87c38a470f3204745'/>
<id>9da5dddafcbb1801b34dfdc87c38a470f3204745</id>
<content type='text'>
[ Upstream commit d66949a1875352d2ddd52b144333288952a9e36f ]

This fixes the following warning:
arch/mips/boot/dts/lantiq/danube_easy50712.dtb: pci@e105400 (lantiq,pci-xway): 'device_type' is a required property
	from schema $id: http://devicetree.org/schemas/pci/pci-bus-common.yaml#

Signed-off-by: Aleksander Jan Bajkowski &lt;olek2@wp.pl&gt;
Signed-off-by: Thomas Bogendoerfer &lt;tsbogend@alpha.franken.de&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit d66949a1875352d2ddd52b144333288952a9e36f ]

This fixes the following warning:
arch/mips/boot/dts/lantiq/danube_easy50712.dtb: pci@e105400 (lantiq,pci-xway): 'device_type' is a required property
	from schema $id: http://devicetree.org/schemas/pci/pci-bus-common.yaml#

Signed-off-by: Aleksander Jan Bajkowski &lt;olek2@wp.pl&gt;
Signed-off-by: Thomas Bogendoerfer &lt;tsbogend@alpha.franken.de&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>mips: lantiq: danube: add missing properties to cpu node</title>
<updated>2025-12-03T11:45:10+00:00</updated>
<author>
<name>Aleksander Jan Bajkowski</name>
<email>olek2@wp.pl</email>
</author>
<published>2025-08-11T11:58:15+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=c09c5057cd04a72ec9638d1cfc6e77ab0e910172'/>
<id>c09c5057cd04a72ec9638d1cfc6e77ab0e910172</id>
<content type='text'>
[ Upstream commit e8dee66c37085dc9858eb8608bc783c2900e50e7 ]

This fixes the following warnings:
arch/mips/boot/dts/lantiq/danube_easy50712.dtb: cpus: '#address-cells' is a required property
	from schema $id: http://devicetree.org/schemas/cpus.yaml#
arch/mips/boot/dts/lantiq/danube_easy50712.dtb: cpus: '#size-cells' is a required property
	from schema $id: http://devicetree.org/schemas/cpus.yaml#
arch/mips/boot/dts/lantiq/danube_easy50712.dtb: cpu@0 (mips,mips24Kc): 'reg' is a required property
	from schema $id: http://devicetree.org/schemas/mips/cpus.yaml#

Signed-off-by: Aleksander Jan Bajkowski &lt;olek2@wp.pl&gt;
Signed-off-by: Thomas Bogendoerfer &lt;tsbogend@alpha.franken.de&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit e8dee66c37085dc9858eb8608bc783c2900e50e7 ]

This fixes the following warnings:
arch/mips/boot/dts/lantiq/danube_easy50712.dtb: cpus: '#address-cells' is a required property
	from schema $id: http://devicetree.org/schemas/cpus.yaml#
arch/mips/boot/dts/lantiq/danube_easy50712.dtb: cpus: '#size-cells' is a required property
	from schema $id: http://devicetree.org/schemas/cpus.yaml#
arch/mips/boot/dts/lantiq/danube_easy50712.dtb: cpu@0 (mips,mips24Kc): 'reg' is a required property
	from schema $id: http://devicetree.org/schemas/mips/cpus.yaml#

Signed-off-by: Aleksander Jan Bajkowski &lt;olek2@wp.pl&gt;
Signed-off-by: Thomas Bogendoerfer &lt;tsbogend@alpha.franken.de&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>powerpc/eeh: Use result of error_detected() in uevent</title>
<updated>2025-12-03T11:45:09+00:00</updated>
<author>
<name>Niklas Schnelle</name>
<email>schnelle@linux.ibm.com</email>
</author>
<published>2025-08-07T13:55:40+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=19d8ac1a1116aac6e10146fa119eefe2e2714204'/>
<id>19d8ac1a1116aac6e10146fa119eefe2e2714204</id>
<content type='text'>
[ Upstream commit 704e5dd1c02371dfc7d22e1520102b197a3b628b ]

Ever since uevent support was added for AER and EEH with commit
856e1eb9bdd4 ("PCI/AER: Add uevents in AER and EEH error/resume"), it
reported PCI_ERS_RESULT_NONE as uevent when recovery begins.

Commit 7b42d97e99d3 ("PCI/ERR: Always report current recovery status for
udev") subsequently amended AER to report the actual return value of
error_detected().

Make the same change to EEH to align it with AER and s390.

Suggested-by: Lukas Wunner &lt;lukas@wunner.de&gt;
Link: https://lore.kernel.org/linux-pci/aIp6LiKJor9KLVpv@wunner.de/
Signed-off-by: Niklas Schnelle &lt;schnelle@linux.ibm.com&gt;
Signed-off-by: Bjorn Helgaas &lt;bhelgaas@google.com&gt;
Reviewed-by: Lukas Wunner &lt;lukas@wunner.de&gt;
Reviewed-by: Kuppuswamy Sathyanarayanan &lt;sathyanarayanan.kuppuswamy@linux.intel.com&gt;
Acked-by: Mahesh Salgaonkar &lt;mahesh@linux.ibm.com&gt;
Link: https://patch.msgid.link/20250807-add_err_uevents-v5-3-adf85b0620b0@linux.ibm.com
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 704e5dd1c02371dfc7d22e1520102b197a3b628b ]

Ever since uevent support was added for AER and EEH with commit
856e1eb9bdd4 ("PCI/AER: Add uevents in AER and EEH error/resume"), it
reported PCI_ERS_RESULT_NONE as uevent when recovery begins.

Commit 7b42d97e99d3 ("PCI/ERR: Always report current recovery status for
udev") subsequently amended AER to report the actual return value of
error_detected().

Make the same change to EEH to align it with AER and s390.

Suggested-by: Lukas Wunner &lt;lukas@wunner.de&gt;
Link: https://lore.kernel.org/linux-pci/aIp6LiKJor9KLVpv@wunner.de/
Signed-off-by: Niklas Schnelle &lt;schnelle@linux.ibm.com&gt;
Signed-off-by: Bjorn Helgaas &lt;bhelgaas@google.com&gt;
Reviewed-by: Lukas Wunner &lt;lukas@wunner.de&gt;
Reviewed-by: Kuppuswamy Sathyanarayanan &lt;sathyanarayanan.kuppuswamy@linux.intel.com&gt;
Acked-by: Mahesh Salgaonkar &lt;mahesh@linux.ibm.com&gt;
Link: https://patch.msgid.link/20250807-add_err_uevents-v5-3-adf85b0620b0@linux.ibm.com
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>x86/vsyscall: Do not require X86_PF_INSTR to emulate vsyscall</title>
<updated>2025-12-03T11:45:09+00:00</updated>
<author>
<name>Kirill A. Shutemov</name>
<email>kirill.shutemov@linux.intel.com</email>
</author>
<published>2025-06-24T14:59:18+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=d6cbf916f2411320b361012f2e7a2604fe1e28c6'/>
<id>d6cbf916f2411320b361012f2e7a2604fe1e28c6</id>
<content type='text'>
[ Upstream commit 8ba38a7a9a699905b84fa97578a8291010dec273 ]

emulate_vsyscall() expects to see X86_PF_INSTR in PFEC on a vsyscall
page fault, but the CPU does not report X86_PF_INSTR if neither
X86_FEATURE_NX nor X86_FEATURE_SMEP are enabled.

X86_FEATURE_NX should be enabled on nearly all 64-bit CPUs, except for
early P4 processors that did not support this feature.

Instead of explicitly checking for X86_PF_INSTR, compare the fault
address to RIP.

On machines with X86_FEATURE_NX enabled, issue a warning if RIP is equal
to fault address but X86_PF_INSTR is absent.

[ dhansen: flesh out code comments ]

Originally-by: Dave Hansen &lt;dave.hansen@intel.com&gt;
Reported-by: Andrew Cooper &lt;andrew.cooper3@citrix.com&gt;
Signed-off-by: Kirill A. Shutemov &lt;kirill.shutemov@linux.intel.com&gt;
Signed-off-by: Dave Hansen &lt;dave.hansen@linux.intel.com&gt;
Reviewed-by: Andrew Cooper &lt;andrew.cooper3@citrix.com&gt;
Link: https://lore.kernel.org/all/bd81a98b-f8d4-4304-ac55-d4151a1a77ab@intel.com
Link: https://lore.kernel.org/all/20250624145918.2720487-1-kirill.shutemov%40linux.intel.com
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 8ba38a7a9a699905b84fa97578a8291010dec273 ]

emulate_vsyscall() expects to see X86_PF_INSTR in PFEC on a vsyscall
page fault, but the CPU does not report X86_PF_INSTR if neither
X86_FEATURE_NX nor X86_FEATURE_SMEP are enabled.

X86_FEATURE_NX should be enabled on nearly all 64-bit CPUs, except for
early P4 processors that did not support this feature.

Instead of explicitly checking for X86_PF_INSTR, compare the fault
address to RIP.

On machines with X86_FEATURE_NX enabled, issue a warning if RIP is equal
to fault address but X86_PF_INSTR is absent.

[ dhansen: flesh out code comments ]

Originally-by: Dave Hansen &lt;dave.hansen@intel.com&gt;
Reported-by: Andrew Cooper &lt;andrew.cooper3@citrix.com&gt;
Signed-off-by: Kirill A. Shutemov &lt;kirill.shutemov@linux.intel.com&gt;
Signed-off-by: Dave Hansen &lt;dave.hansen@linux.intel.com&gt;
Reviewed-by: Andrew Cooper &lt;andrew.cooper3@citrix.com&gt;
Link: https://lore.kernel.org/all/bd81a98b-f8d4-4304-ac55-d4151a1a77ab@intel.com
Link: https://lore.kernel.org/all/20250624145918.2720487-1-kirill.shutemov%40linux.intel.com
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>arc: Fix __fls() const-foldability via __builtin_clzl()</title>
<updated>2025-12-03T11:45:07+00:00</updated>
<author>
<name>Kees Cook</name>
<email>kees@kernel.org</email>
</author>
<published>2025-08-31T02:23:53+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=5d4f0c29f34a85a4c91c380a2d2270fb86555f09'/>
<id>5d4f0c29f34a85a4c91c380a2d2270fb86555f09</id>
<content type='text'>
[ Upstream commit a3fecb9160482367365cc384c59dd220b162b066 ]

While tracking down a problem where constant expressions used by
BUILD_BUG_ON() suddenly stopped working[1], we found that an added static
initializer was convincing the compiler that it couldn't track the state
of the prior statically initialized value. Tracing this down found that
ffs() was used in the initializer macro, but since it wasn't marked with
__attribute__const__, the compiler had to assume the function might
change variable states as a side-effect (which is not true for ffs(),
which provides deterministic math results).

For arc architecture with CONFIG_ISA_ARCV2=y, the __fls() function
uses __builtin_arc_fls() which lacks GCC's const attribute, preventing
compile-time constant folding, and KUnit testing of ffs/fls fails on
arc[3]. A patch[2] to GCC to solve this has been sent.

Add a fix for this by handling compile-time constants with the standard
__builtin_clzl() builtin (which has const attribute) while preserving
the optimized arc-specific builtin for runtime cases. This has the added
benefit of skipping runtime calculation of compile-time constant values.
Even with the GCC bug fixed (which is about "attribute const") this is a
good change to avoid needless runtime costs, and should be done
regardless of the state of GCC's bug.

Build tested ARCH=arc allyesconfig with GCC arc-linux 15.2.0.

Link: https://github.com/KSPP/linux/issues/364 [1]
Link: https://gcc.gnu.org/pipermail/gcc-patches/2025-August/693273.html
Reported-by: kernel test robot &lt;lkp@intel.com&gt;
Closes: https://lore.kernel.org/oe-kbuild-all/202508031025.doWxtzzc-lkp@intel.com/ [3]
Signed-off-by: Kees Cook &lt;kees@kernel.org&gt;
Acked-by: Vineet Gupta &lt;vgupta@kernel.org&gt;
Signed-off-by: Yury Norov (NVIDIA) &lt;yury.norov@gmail.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit a3fecb9160482367365cc384c59dd220b162b066 ]

While tracking down a problem where constant expressions used by
BUILD_BUG_ON() suddenly stopped working[1], we found that an added static
initializer was convincing the compiler that it couldn't track the state
of the prior statically initialized value. Tracing this down found that
ffs() was used in the initializer macro, but since it wasn't marked with
__attribute__const__, the compiler had to assume the function might
change variable states as a side-effect (which is not true for ffs(),
which provides deterministic math results).

For arc architecture with CONFIG_ISA_ARCV2=y, the __fls() function
uses __builtin_arc_fls() which lacks GCC's const attribute, preventing
compile-time constant folding, and KUnit testing of ffs/fls fails on
arc[3]. A patch[2] to GCC to solve this has been sent.

Add a fix for this by handling compile-time constants with the standard
__builtin_clzl() builtin (which has const attribute) while preserving
the optimized arc-specific builtin for runtime cases. This has the added
benefit of skipping runtime calculation of compile-time constant values.
Even with the GCC bug fixed (which is about "attribute const") this is a
good change to avoid needless runtime costs, and should be done
regardless of the state of GCC's bug.

Build tested ARCH=arc allyesconfig with GCC arc-linux 15.2.0.

Link: https://github.com/KSPP/linux/issues/364 [1]
Link: https://gcc.gnu.org/pipermail/gcc-patches/2025-August/693273.html
Reported-by: kernel test robot &lt;lkp@intel.com&gt;
Closes: https://lore.kernel.org/oe-kbuild-all/202508031025.doWxtzzc-lkp@intel.com/ [3]
Signed-off-by: Kees Cook &lt;kees@kernel.org&gt;
Acked-by: Vineet Gupta &lt;vgupta@kernel.org&gt;
Signed-off-by: Yury Norov (NVIDIA) &lt;yury.norov@gmail.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>x86/resctrl: Fix miscount of bandwidth event when reactivating previously unavailable RMID</title>
<updated>2025-12-03T11:45:05+00:00</updated>
<author>
<name>Babu Moger</name>
<email>babu.moger@amd.com</email>
</author>
<published>2025-10-28T19:59:04+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=7c525ad1743d23fa2416ee3306c8ad157a0b8be1'/>
<id>7c525ad1743d23fa2416ee3306c8ad157a0b8be1</id>
<content type='text'>
[ Upstream commit 15292f1b4c55a3a7c940dbcb6cb8793871ed3d92 ]

Users can create as many monitoring groups as the number of RMIDs supported
by the hardware. However, on AMD systems, only a limited number of RMIDs
are guaranteed to be actively tracked by the hardware. RMIDs that exceed
this limit are placed in an "Unavailable" state.

When a bandwidth counter is read for such an RMID, the hardware sets
MSR_IA32_QM_CTR.Unavailable (bit 62). When such an RMID starts being tracked
again the hardware counter is reset to zero. MSR_IA32_QM_CTR.Unavailable
remains set on first read after tracking re-starts and is clear on all
subsequent reads as long as the RMID is tracked.

resctrl miscounts the bandwidth events after an RMID transitions from the
"Unavailable" state back to being tracked. This happens because when the
hardware starts counting again after resetting the counter to zero, resctrl
in turn compares the new count against the counter value stored from the
previous time the RMID was tracked.

This results in resctrl computing an event value that is either undercounting
(when new counter is more than stored counter) or a mistaken overflow (when
new counter is less than stored counter).

Reset the stored value (arch_mbm_state::prev_msr) of MSR_IA32_QM_CTR to
zero whenever the RMID is in the "Unavailable" state to ensure accurate
counting after the RMID resets to zero when it starts to be tracked again.

Example scenario that results in mistaken overflow
==================================================
1. The resctrl filesystem is mounted, and a task is assigned to a
   monitoring group.

   $mount -t resctrl resctrl /sys/fs/resctrl
   $mkdir /sys/fs/resctrl/mon_groups/test1/
   $echo 1234 &gt; /sys/fs/resctrl/mon_groups/test1/tasks

   $cat /sys/fs/resctrl/mon_groups/test1/mon_data/mon_L3_*/mbm_total_bytes
   21323            &lt;- Total bytes on domain 0
   "Unavailable"    &lt;- Total bytes on domain 1

   Task is running on domain 0. Counter on domain 1 is "Unavailable".

2. The task runs on domain 0 for a while and then moves to domain 1. The
   counter starts incrementing on domain 1.

   $cat /sys/fs/resctrl/mon_groups/test1/mon_data/mon_L3_*/mbm_total_bytes
   7345357          &lt;- Total bytes on domain 0
   4545             &lt;- Total bytes on domain 1

3. At some point, the RMID in domain 0 transitions to the "Unavailable"
   state because the task is no longer executing in that domain.

   $cat /sys/fs/resctrl/mon_groups/test1/mon_data/mon_L3_*/mbm_total_bytes
   "Unavailable"    &lt;- Total bytes on domain 0
   434341           &lt;- Total bytes on domain 1

4.  Since the task continues to migrate between domains, it may eventually
    return to domain 0.

    $cat /sys/fs/resctrl/mon_groups/test1/mon_data/mon_L3_*/mbm_total_bytes
    17592178699059  &lt;- Overflow on domain 0
    3232332         &lt;- Total bytes on domain 1

In this case, the RMID on domain 0 transitions from "Unavailable" state to
active state. The hardware sets MSR_IA32_QM_CTR.Unavailable (bit 62) when
the counter is read and begins tracking the RMID counting from 0.

Subsequent reads succeed but return a value smaller than the previously
saved MSR value (7345357). Consequently, the resctrl's overflow logic is
triggered, it compares the previous value (7345357) with the new, smaller
value and incorrectly interprets this as a counter overflow, adding a large
delta.

In reality, this is a false positive: the counter did not overflow but was
simply reset when the RMID transitioned from "Unavailable" back to active
state.

Here is the text from APM [1] available from [2].

"In PQOS Version 2.0 or higher, the MBM hardware will set the U bit on the
first QM_CTR read when it begins tracking an RMID that it was not
previously tracking. The U bit will be zero for all subsequent reads from
that RMID while it is still tracked by the hardware. Therefore, a QM_CTR
read with the U bit set when that RMID is in use by a processor can be
considered 0 when calculating the difference with a subsequent read."

[1] AMD64 Architecture Programmer's Manual Volume 2: System Programming
    Publication # 24593 Revision 3.41 section 19.3.3 Monitoring L3 Memory
    Bandwidth (MBM).

  [ bp: Split commit message into smaller paragraph chunks for better
    consumption. ]

Fixes: 4d05bf71f157d ("x86/resctrl: Introduce AMD QOS feature")
Signed-off-by: Babu Moger &lt;babu.moger@amd.com&gt;
Signed-off-by: Borislav Petkov (AMD) &lt;bp@alien8.de&gt;
Reviewed-by: Reinette Chatre &lt;reinette.chatre@intel.com&gt;
Tested-by: Reinette Chatre &lt;reinette.chatre@intel.com&gt;
Cc: stable@vger.kernel.org # needs adjustments for &lt;= v6.17
Link: https://bugzilla.kernel.org/show_bug.cgi?id=206537 # [2]
(cherry picked from commit 15292f1b4c55a3a7c940dbcb6cb8793871ed3d92)
[babu.moger@amd.com: Backport for v5.4 stable]
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 15292f1b4c55a3a7c940dbcb6cb8793871ed3d92 ]

Users can create as many monitoring groups as the number of RMIDs supported
by the hardware. However, on AMD systems, only a limited number of RMIDs
are guaranteed to be actively tracked by the hardware. RMIDs that exceed
this limit are placed in an "Unavailable" state.

When a bandwidth counter is read for such an RMID, the hardware sets
MSR_IA32_QM_CTR.Unavailable (bit 62). When such an RMID starts being tracked
again the hardware counter is reset to zero. MSR_IA32_QM_CTR.Unavailable
remains set on first read after tracking re-starts and is clear on all
subsequent reads as long as the RMID is tracked.

resctrl miscounts the bandwidth events after an RMID transitions from the
"Unavailable" state back to being tracked. This happens because when the
hardware starts counting again after resetting the counter to zero, resctrl
in turn compares the new count against the counter value stored from the
previous time the RMID was tracked.

This results in resctrl computing an event value that is either undercounting
(when new counter is more than stored counter) or a mistaken overflow (when
new counter is less than stored counter).

Reset the stored value (arch_mbm_state::prev_msr) of MSR_IA32_QM_CTR to
zero whenever the RMID is in the "Unavailable" state to ensure accurate
counting after the RMID resets to zero when it starts to be tracked again.

Example scenario that results in mistaken overflow
==================================================
1. The resctrl filesystem is mounted, and a task is assigned to a
   monitoring group.

   $mount -t resctrl resctrl /sys/fs/resctrl
   $mkdir /sys/fs/resctrl/mon_groups/test1/
   $echo 1234 &gt; /sys/fs/resctrl/mon_groups/test1/tasks

   $cat /sys/fs/resctrl/mon_groups/test1/mon_data/mon_L3_*/mbm_total_bytes
   21323            &lt;- Total bytes on domain 0
   "Unavailable"    &lt;- Total bytes on domain 1

   Task is running on domain 0. Counter on domain 1 is "Unavailable".

2. The task runs on domain 0 for a while and then moves to domain 1. The
   counter starts incrementing on domain 1.

   $cat /sys/fs/resctrl/mon_groups/test1/mon_data/mon_L3_*/mbm_total_bytes
   7345357          &lt;- Total bytes on domain 0
   4545             &lt;- Total bytes on domain 1

3. At some point, the RMID in domain 0 transitions to the "Unavailable"
   state because the task is no longer executing in that domain.

   $cat /sys/fs/resctrl/mon_groups/test1/mon_data/mon_L3_*/mbm_total_bytes
   "Unavailable"    &lt;- Total bytes on domain 0
   434341           &lt;- Total bytes on domain 1

4.  Since the task continues to migrate between domains, it may eventually
    return to domain 0.

    $cat /sys/fs/resctrl/mon_groups/test1/mon_data/mon_L3_*/mbm_total_bytes
    17592178699059  &lt;- Overflow on domain 0
    3232332         &lt;- Total bytes on domain 1

In this case, the RMID on domain 0 transitions from "Unavailable" state to
active state. The hardware sets MSR_IA32_QM_CTR.Unavailable (bit 62) when
the counter is read and begins tracking the RMID counting from 0.

Subsequent reads succeed but return a value smaller than the previously
saved MSR value (7345357). Consequently, the resctrl's overflow logic is
triggered, it compares the previous value (7345357) with the new, smaller
value and incorrectly interprets this as a counter overflow, adding a large
delta.

In reality, this is a false positive: the counter did not overflow but was
simply reset when the RMID transitioned from "Unavailable" back to active
state.

Here is the text from APM [1] available from [2].

"In PQOS Version 2.0 or higher, the MBM hardware will set the U bit on the
first QM_CTR read when it begins tracking an RMID that it was not
previously tracking. The U bit will be zero for all subsequent reads from
that RMID while it is still tracked by the hardware. Therefore, a QM_CTR
read with the U bit set when that RMID is in use by a processor can be
considered 0 when calculating the difference with a subsequent read."

[1] AMD64 Architecture Programmer's Manual Volume 2: System Programming
    Publication # 24593 Revision 3.41 section 19.3.3 Monitoring L3 Memory
    Bandwidth (MBM).

  [ bp: Split commit message into smaller paragraph chunks for better
    consumption. ]

Fixes: 4d05bf71f157d ("x86/resctrl: Introduce AMD QOS feature")
Signed-off-by: Babu Moger &lt;babu.moger@amd.com&gt;
Signed-off-by: Borislav Petkov (AMD) &lt;bp@alien8.de&gt;
Reviewed-by: Reinette Chatre &lt;reinette.chatre@intel.com&gt;
Tested-by: Reinette Chatre &lt;reinette.chatre@intel.com&gt;
Cc: stable@vger.kernel.org # needs adjustments for &lt;= v6.17
Link: https://bugzilla.kernel.org/show_bug.cgi?id=206537 # [2]
(cherry picked from commit 15292f1b4c55a3a7c940dbcb6cb8793871ed3d92)
[babu.moger@amd.com: Backport for v5.4 stable]
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>x86/bugs: Fix reporting of LFENCE retpoline</title>
<updated>2025-12-03T11:45:04+00:00</updated>
<author>
<name>David Kaplan</name>
<email>david.kaplan@amd.com</email>
</author>
<published>2025-09-15T13:47:05+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=1657166c1f60eb3d80cfee574a21de688920c6e5'/>
<id>1657166c1f60eb3d80cfee574a21de688920c6e5</id>
<content type='text'>
[ Upstream commit d1cc1baef67ac6c09b74629ca053bf3fb812f7dc ]

The LFENCE retpoline mitigation is not secure but the kernel prints
inconsistent messages about this fact.  The dmesg log says 'Mitigation:
LFENCE', implying the system is mitigated.  But sysfs reports 'Vulnerable:
LFENCE' implying the system (correctly) is not mitigated.

Fix this by printing a consistent 'Vulnerable: LFENCE' string everywhere
when this mitigation is selected.

Signed-off-by: David Kaplan &lt;david.kaplan@amd.com&gt;
Signed-off-by: Borislav Petkov (AMD) &lt;bp@alien8.de&gt;
Link: https://lore.kernel.org/20250915134706.3201818-1-david.kaplan@amd.com
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit d1cc1baef67ac6c09b74629ca053bf3fb812f7dc ]

The LFENCE retpoline mitigation is not secure but the kernel prints
inconsistent messages about this fact.  The dmesg log says 'Mitigation:
LFENCE', implying the system is mitigated.  But sysfs reports 'Vulnerable:
LFENCE' implying the system (correctly) is not mitigated.

Fix this by printing a consistent 'Vulnerable: LFENCE' string everywhere
when this mitigation is selected.

Signed-off-by: David Kaplan &lt;david.kaplan@amd.com&gt;
Signed-off-by: Borislav Petkov (AMD) &lt;bp@alien8.de&gt;
Link: https://lore.kernel.org/20250915134706.3201818-1-david.kaplan@amd.com
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
</feed>
