<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-stable.git/drivers/nvmem, branch linux-5.4.y</title>
<subtitle>Linux kernel stable tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/'/>
<entry>
<title>nvmem: core: improve range check for nvmem_cell_write()</title>
<updated>2025-03-13T11:43:10+00:00</updated>
<author>
<name>Jennifer Berringer</name>
<email>jberring@redhat.com</email>
</author>
<published>2024-12-30T14:19:01+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=406c63ceeae3851fba6b52e423fb4efc736f6f4e'/>
<id>406c63ceeae3851fba6b52e423fb4efc736f6f4e</id>
<content type='text'>
commit 31507fc2ad36e0071751a710449db19c85d82a7f upstream.

When __nvmem_cell_entry_write() is called for an nvmem cell that does
not need bit shifting, it requires that the len parameter exactly
matches the nvmem cell size. However, when the nvmem cell has a nonzero
bit_offset, it was skipping this check.

Accepting values of len larger than the cell size results in
nvmem_cell_prepare_write_buffer() trying to write past the end of a heap
buffer that it allocates. Add a check to avoid that problem and instead
return -EINVAL when len doesn't match the number of bits expected by the
nvmem cell when bit_offset is nonzero.

This check uses cell-&gt;nbits in order to allow providing the smaller size
to cells that are shifted into another byte by bit_offset. For example,
a cell with nbits=8 and nonzero bit_offset would have bytes=2 but should
accept a 1-byte write here, although no current callers depend on this.

Fixes: 69aba7948cbe ("nvmem: Add a simple NVMEM framework for consumers")
Cc: stable@vger.kernel.org
Signed-off-by: Jennifer Berringer &lt;jberring@redhat.com&gt;
Signed-off-by: Srinivas Kandagatla &lt;srinivas.kandagatla@linaro.org&gt;
Link: https://lore.kernel.org/r/20241230141901.263976-7-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&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 31507fc2ad36e0071751a710449db19c85d82a7f upstream.

When __nvmem_cell_entry_write() is called for an nvmem cell that does
not need bit shifting, it requires that the len parameter exactly
matches the nvmem cell size. However, when the nvmem cell has a nonzero
bit_offset, it was skipping this check.

Accepting values of len larger than the cell size results in
nvmem_cell_prepare_write_buffer() trying to write past the end of a heap
buffer that it allocates. Add a check to avoid that problem and instead
return -EINVAL when len doesn't match the number of bits expected by the
nvmem cell when bit_offset is nonzero.

This check uses cell-&gt;nbits in order to allow providing the smaller size
to cells that are shifted into another byte by bit_offset. For example,
a cell with nbits=8 and nonzero bit_offset would have bytes=2 but should
accept a 1-byte write here, although no current callers depend on this.

Fixes: 69aba7948cbe ("nvmem: Add a simple NVMEM framework for consumers")
Cc: stable@vger.kernel.org
Signed-off-by: Jennifer Berringer &lt;jberring@redhat.com&gt;
Signed-off-by: Srinivas Kandagatla &lt;srinivas.kandagatla@linaro.org&gt;
Link: https://lore.kernel.org/r/20241230141901.263976-7-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>nvmem: Fix return type of devm_nvmem_device_get() in kerneldoc</title>
<updated>2024-09-12T09:03:55+00:00</updated>
<author>
<name>Geert Uytterhoeven</name>
<email>geert+renesas@glider.be</email>
</author>
<published>2024-09-02T14:25:09+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=e8c5ba894181a698d7143975fb5918ce58c19883'/>
<id>e8c5ba894181a698d7143975fb5918ce58c19883</id>
<content type='text'>
commit c69f37f6559a8948d70badd2b179db7714dedd62 upstream.

devm_nvmem_device_get() returns an nvmem device, not an nvmem cell.

Fixes: e2a5402ec7c6d044 ("nvmem: Add nvmem_device based consumer apis.")
Cc: stable &lt;stable@kernel.org&gt;
Signed-off-by: Geert Uytterhoeven &lt;geert+renesas@glider.be&gt;
Signed-off-by: Srinivas Kandagatla &lt;srinivas.kandagatla@linaro.org&gt;
Link: https://lore.kernel.org/r/20240902142510.71096-3-srinivas.kandagatla@linaro.org
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 c69f37f6559a8948d70badd2b179db7714dedd62 upstream.

devm_nvmem_device_get() returns an nvmem device, not an nvmem cell.

Fixes: e2a5402ec7c6d044 ("nvmem: Add nvmem_device based consumer apis.")
Cc: stable &lt;stable@kernel.org&gt;
Signed-off-by: Geert Uytterhoeven &lt;geert+renesas@glider.be&gt;
Signed-off-by: Srinivas Kandagatla &lt;srinivas.kandagatla@linaro.org&gt;
Link: https://lore.kernel.org/r/20240902142510.71096-3-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>nvmem: meson-efuse: Fix return value of nvmem callbacks</title>
<updated>2024-07-18T09:40:55+00:00</updated>
<author>
<name>Joy Chakraborty</name>
<email>joychakr@google.com</email>
</author>
<published>2024-06-28T11:37:02+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=427524ff3085bbd5b67b8cae41fa68359dcec8bf'/>
<id>427524ff3085bbd5b67b8cae41fa68359dcec8bf</id>
<content type='text'>
commit 7a0a6d0a7c805f9380381f4deedffdf87b93f408 upstream.

Read/write callbacks registered with nvmem core expect 0 to be returned
on success and a negative value to be returned on failure.

meson_efuse_read() and meson_efuse_write() call into
meson_sm_call_read() and meson_sm_call_write() respectively which return
the number of bytes read or written on success as per their api
description.

Fix to return error if meson_sm_call_read()/meson_sm_call_write()
returns an error else return 0.

Fixes: a29a63bdaf6f ("nvmem: meson-efuse: simplify read callback")
Cc: stable@vger.kernel.org
Signed-off-by: Joy Chakraborty &lt;joychakr@google.com&gt;
Reviewed-by: Dan Carpenter &lt;dan.carpenter@linaro.org&gt;
Reviewed-by: Neil Armstrong &lt;neil.armstrong@linaro.org&gt;
Signed-off-by: Srinivas Kandagatla &lt;srinivas.kandagatla@linaro.org&gt;
Link: https://lore.kernel.org/r/20240628113704.13742-3-srinivas.kandagatla@linaro.org
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 7a0a6d0a7c805f9380381f4deedffdf87b93f408 upstream.

Read/write callbacks registered with nvmem core expect 0 to be returned
on success and a negative value to be returned on failure.

meson_efuse_read() and meson_efuse_write() call into
meson_sm_call_read() and meson_sm_call_write() respectively which return
the number of bytes read or written on success as per their api
description.

Fix to return error if meson_sm_call_read()/meson_sm_call_write()
returns an error else return 0.

Fixes: a29a63bdaf6f ("nvmem: meson-efuse: simplify read callback")
Cc: stable@vger.kernel.org
Signed-off-by: Joy Chakraborty &lt;joychakr@google.com&gt;
Reviewed-by: Dan Carpenter &lt;dan.carpenter@linaro.org&gt;
Reviewed-by: Neil Armstrong &lt;neil.armstrong@linaro.org&gt;
Signed-off-by: Srinivas Kandagatla &lt;srinivas.kandagatla@linaro.org&gt;
Link: https://lore.kernel.org/r/20240628113704.13742-3-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>nvmem: meson-efuse: fix function pointer type mismatch</title>
<updated>2024-04-13T10:51:26+00:00</updated>
<author>
<name>Jerome Brunet</name>
<email>jbrunet@baylibre.com</email>
</author>
<published>2024-02-24T11:40:23+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=aec74a14d1945b8217992646b6f0d118432ce648'/>
<id>aec74a14d1945b8217992646b6f0d118432ce648</id>
<content type='text'>
[ Upstream commit cbd38332c140829ab752ba4e727f98be5c257f18 ]

clang-16 warns about casting functions to incompatible types, as is done
here to call clk_disable_unprepare:

drivers/nvmem/meson-efuse.c:78:12: error: cast from 'void (*)(struct clk *)' to 'void (*)(void *)' converts to incompatible function type [-Werror,-Wcast-function-type-strict]
   78 |                                        (void(*)(void *))clk_disable_unprepare,

The pattern of getting, enabling and setting a disable callback for a
clock can be replaced with devm_clk_get_enabled(), which also fixes
this warning.

Fixes: 611fbca1c861 ("nvmem: meson-efuse: add peripheral clock")
Cc: Stable@vger.kernel.org
Reported-by: Arnd Bergmann &lt;arnd@arndb.de&gt;
Signed-off-by: Jerome Brunet &lt;jbrunet@baylibre.com&gt;
Reviewed-by: Martin Blumenstingl &lt;martin.blumenstingl@googlemail.com&gt;
Acked-by: Arnd Bergmann &lt;arnd@arndb.de&gt;
Reviewed-by: Justin Stitt &lt;justinstitt@google.com&gt;
Signed-off-by: Srinivas Kandagatla &lt;srinivas.kandagatla@linaro.org&gt;
Link: https://lore.kernel.org/r/20240224114023.85535-2-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&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 cbd38332c140829ab752ba4e727f98be5c257f18 ]

clang-16 warns about casting functions to incompatible types, as is done
here to call clk_disable_unprepare:

drivers/nvmem/meson-efuse.c:78:12: error: cast from 'void (*)(struct clk *)' to 'void (*)(void *)' converts to incompatible function type [-Werror,-Wcast-function-type-strict]
   78 |                                        (void(*)(void *))clk_disable_unprepare,

The pattern of getting, enabling and setting a disable callback for a
clock can be replaced with devm_clk_get_enabled(), which also fixes
this warning.

Fixes: 611fbca1c861 ("nvmem: meson-efuse: add peripheral clock")
Cc: Stable@vger.kernel.org
Reported-by: Arnd Bergmann &lt;arnd@arndb.de&gt;
Signed-off-by: Jerome Brunet &lt;jbrunet@baylibre.com&gt;
Reviewed-by: Martin Blumenstingl &lt;martin.blumenstingl@googlemail.com&gt;
Acked-by: Arnd Bergmann &lt;arnd@arndb.de&gt;
Reviewed-by: Justin Stitt &lt;justinstitt@google.com&gt;
Signed-off-by: Srinivas Kandagatla &lt;srinivas.kandagatla@linaro.org&gt;
Link: https://lore.kernel.org/r/20240224114023.85535-2-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>firmware: meson_sm: Rework driver as a proper platform driver</title>
<updated>2024-04-13T10:51:26+00:00</updated>
<author>
<name>Carlo Caione</name>
<email>ccaione@baylibre.com</email>
</author>
<published>2019-07-31T08:23:39+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=525ae72d9f0b5cf027f1c78c84e41c90e86df026'/>
<id>525ae72d9f0b5cf027f1c78c84e41c90e86df026</id>
<content type='text'>
[ Upstream commit 8cde3c2153e8f57be884c0e73f18bc4de150e870 ]

The secure monitor driver is currently a frankenstein driver which is
registered as a platform driver but its functionality goes through a
global struct accessed by the consumer drivers using exported helper
functions.

Try to tidy up the driver moving the firmware struct into the driver
data and make the consumer drivers referencing the secure-monitor using
a new property in the DT.

Currently only the nvmem driver is using this API so we can fix it in
the same commit.

Reviewed-by: Jerome Brunet &lt;jbrunet@baylibre.com&gt;
Signed-off-by: Carlo Caione &lt;ccaione@baylibre.com&gt;
Signed-off-by: Kevin Hilman &lt;khilman@baylibre.com&gt;
Stable-dep-of: cbd38332c140 ("nvmem: meson-efuse: fix function pointer type mismatch")
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 8cde3c2153e8f57be884c0e73f18bc4de150e870 ]

The secure monitor driver is currently a frankenstein driver which is
registered as a platform driver but its functionality goes through a
global struct accessed by the consumer drivers using exported helper
functions.

Try to tidy up the driver moving the firmware struct into the driver
data and make the consumer drivers referencing the secure-monitor using
a new property in the DT.

Currently only the nvmem driver is using this API so we can fix it in
the same commit.

Reviewed-by: Jerome Brunet &lt;jbrunet@baylibre.com&gt;
Signed-off-by: Carlo Caione &lt;ccaione@baylibre.com&gt;
Signed-off-by: Kevin Hilman &lt;khilman@baylibre.com&gt;
Stable-dep-of: cbd38332c140 ("nvmem: meson-efuse: fix function pointer type mismatch")
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>nvmem: imx: correct nregs for i.MX6UL</title>
<updated>2023-11-08T10:23:37+00:00</updated>
<author>
<name>Peng Fan</name>
<email>peng.fan@nxp.com</email>
</author>
<published>2023-10-13T12:49:03+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=8de78231cba91267355f76aa4c89ffbd7cd9f943'/>
<id>8de78231cba91267355f76aa4c89ffbd7cd9f943</id>
<content type='text'>
commit 7d6e10f5d254681983b53d979422c8de3fadbefb upstream.

The nregs for i.MX6UL should be 144 per fuse map, correct it.

Fixes: 4aa2b4802046 ("nvmem: octop: Add support for imx6ul")
Cc: Stable@vger.kernel.org
Signed-off-by: Peng Fan &lt;peng.fan@nxp.com&gt;
Signed-off-by: Srinivas Kandagatla &lt;srinivas.kandagatla@linaro.org&gt;
Link: https://lore.kernel.org/r/20231013124904.175782-3-srinivas.kandagatla@linaro.org
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 7d6e10f5d254681983b53d979422c8de3fadbefb upstream.

The nregs for i.MX6UL should be 144 per fuse map, correct it.

Fixes: 4aa2b4802046 ("nvmem: octop: Add support for imx6ul")
Cc: Stable@vger.kernel.org
Signed-off-by: Peng Fan &lt;peng.fan@nxp.com&gt;
Signed-off-by: Srinivas Kandagatla &lt;srinivas.kandagatla@linaro.org&gt;
Link: https://lore.kernel.org/r/20231013124904.175782-3-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>nvmem: imx: correct nregs for i.MX6SLL</title>
<updated>2023-11-08T10:23:37+00:00</updated>
<author>
<name>Peng Fan</name>
<email>peng.fan@nxp.com</email>
</author>
<published>2023-10-13T12:49:02+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=0b2c3a8601ccba2caaa7f866ff2829047827820b'/>
<id>0b2c3a8601ccba2caaa7f866ff2829047827820b</id>
<content type='text'>
commit 414a98abbefd82d591f4e2d1efd2917bcd3b6f6d upstream.

The nregs for i.MX6SLL should be 80 per fuse map, correct it.

Fixes: 6da27821a6f5 ("nvmem: imx-ocotp: add support for imx6sll")
Cc: Stable@vger.kernel.org
Signed-off-by: Peng Fan &lt;peng.fan@nxp.com&gt;
Signed-off-by: Srinivas Kandagatla &lt;srinivas.kandagatla@linaro.org&gt;
Link: https://lore.kernel.org/r/20231013124904.175782-2-srinivas.kandagatla@linaro.org
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 414a98abbefd82d591f4e2d1efd2917bcd3b6f6d upstream.

The nregs for i.MX6SLL should be 80 per fuse map, correct it.

Fixes: 6da27821a6f5 ("nvmem: imx-ocotp: add support for imx6sll")
Cc: Stable@vger.kernel.org
Signed-off-by: Peng Fan &lt;peng.fan@nxp.com&gt;
Signed-off-by: Srinivas Kandagatla &lt;srinivas.kandagatla@linaro.org&gt;
Link: https://lore.kernel.org/r/20231013124904.175782-2-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>nvmem: imx: correct nregs for i.MX6ULL</title>
<updated>2023-11-08T10:23:37+00:00</updated>
<author>
<name>Peng Fan</name>
<email>peng.fan@nxp.com</email>
</author>
<published>2023-10-13T12:49:04+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=6063678df7fa3d5bdfb7314bf7721a24a99618ee'/>
<id>6063678df7fa3d5bdfb7314bf7721a24a99618ee</id>
<content type='text'>
commit 2382c1b044231fd49eaf9aa82bc7113fc55487b8 upstream.

The nregs for i.MX6ULL should be 80 per fuse map, correct it.

Fixes: ffbc34bf0e9c ("nvmem: imx-ocotp: Implement i.MX6ULL/ULZ support")
Cc: Stable@vger.kernel.org
Signed-off-by: Peng Fan &lt;peng.fan@nxp.com&gt;
Signed-off-by: Srinivas Kandagatla &lt;srinivas.kandagatla@linaro.org&gt;
Link: https://lore.kernel.org/r/20231013124904.175782-4-srinivas.kandagatla@linaro.org
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 2382c1b044231fd49eaf9aa82bc7113fc55487b8 upstream.

The nregs for i.MX6ULL should be 80 per fuse map, correct it.

Fixes: ffbc34bf0e9c ("nvmem: imx-ocotp: Implement i.MX6ULL/ULZ support")
Cc: Stable@vger.kernel.org
Signed-off-by: Peng Fan &lt;peng.fan@nxp.com&gt;
Signed-off-by: Srinivas Kandagatla &lt;srinivas.kandagatla@linaro.org&gt;
Link: https://lore.kernel.org/r/20231013124904.175782-4-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>nvmem: core: fix cell removal on error</title>
<updated>2023-02-22T11:50:28+00:00</updated>
<author>
<name>Michael Walle</name>
<email>michael@walle.cc</email>
</author>
<published>2023-01-27T10:40:13+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=ce62df33fcfff0c6bc73355f2879f917146c8223'/>
<id>ce62df33fcfff0c6bc73355f2879f917146c8223</id>
<content type='text'>
commit db3546d58b5a0fa581d9c9f2bdc2856fa6c5e43e upstream.

nvmem_add_cells() could return an error after some cells are already
added to the provider. In this case, the added cells are not removed.
Remove any registered cells if nvmem_add_cells() fails.

Fixes: fa72d847d68d7 ("nvmem: check the return value of nvmem_add_cells()")
Cc: stable@vger.kernel.org
Signed-off-by: Michael Walle &lt;michael@walle.cc&gt;
Signed-off-by: Srinivas Kandagatla &lt;srinivas.kandagatla@linaro.org&gt;
Link: https://lore.kernel.org/r/20230127104015.23839-9-srinivas.kandagatla@linaro.org
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 db3546d58b5a0fa581d9c9f2bdc2856fa6c5e43e upstream.

nvmem_add_cells() could return an error after some cells are already
added to the provider. In this case, the added cells are not removed.
Remove any registered cells if nvmem_add_cells() fails.

Fixes: fa72d847d68d7 ("nvmem: check the return value of nvmem_add_cells()")
Cc: stable@vger.kernel.org
Signed-off-by: Michael Walle &lt;michael@walle.cc&gt;
Signed-off-by: Srinivas Kandagatla &lt;srinivas.kandagatla@linaro.org&gt;
Link: https://lore.kernel.org/r/20230127104015.23839-9-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>nvmem: Fix shift-out-of-bound (UBSAN) with byte size cells</title>
<updated>2021-10-20T09:40:14+00:00</updated>
<author>
<name>Stephen Boyd</name>
<email>swboyd@chromium.org</email>
</author>
<published>2021-10-13T12:45:11+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=0594f1d048d8dc338eb9a240021b1d00ae1eb082'/>
<id>0594f1d048d8dc338eb9a240021b1d00ae1eb082</id>
<content type='text'>
commit 5d388fa01fa6eb310ac023a363a6cb216d9d8fe9 upstream.

If a cell has 'nbits' equal to a multiple of BITS_PER_BYTE the logic

 *p &amp;= GENMASK((cell-&gt;nbits%BITS_PER_BYTE) - 1, 0);

will become undefined behavior because nbits modulo BITS_PER_BYTE is 0, and we
subtract one from that making a large number that is then shifted more than the
number of bits that fit into an unsigned long.

UBSAN reports this problem:

 UBSAN: shift-out-of-bounds in drivers/nvmem/core.c:1386:8
 shift exponent 64 is too large for 64-bit type 'unsigned long'
 CPU: 6 PID: 7 Comm: kworker/u16:0 Not tainted 5.15.0-rc3+ #9
 Hardware name: Google Lazor (rev3+) with KB Backlight (DT)
 Workqueue: events_unbound deferred_probe_work_func
 Call trace:
  dump_backtrace+0x0/0x170
  show_stack+0x24/0x30
  dump_stack_lvl+0x64/0x7c
  dump_stack+0x18/0x38
  ubsan_epilogue+0x10/0x54
  __ubsan_handle_shift_out_of_bounds+0x180/0x194
  __nvmem_cell_read+0x1ec/0x21c
  nvmem_cell_read+0x58/0x94
  nvmem_cell_read_variable_common+0x4c/0xb0
  nvmem_cell_read_variable_le_u32+0x40/0x100
  a6xx_gpu_init+0x170/0x2f4
  adreno_bind+0x174/0x284
  component_bind_all+0xf0/0x264
  msm_drm_bind+0x1d8/0x7a0
  try_to_bring_up_master+0x164/0x1ac
  __component_add+0xbc/0x13c
  component_add+0x20/0x2c
  dp_display_probe+0x340/0x384
  platform_probe+0xc0/0x100
  really_probe+0x110/0x304
  __driver_probe_device+0xb8/0x120
  driver_probe_device+0x4c/0xfc
  __device_attach_driver+0xb0/0x128
  bus_for_each_drv+0x90/0xdc
  __device_attach+0xc8/0x174
  device_initial_probe+0x20/0x2c
  bus_probe_device+0x40/0xa4
  deferred_probe_work_func+0x7c/0xb8
  process_one_work+0x128/0x21c
  process_scheduled_works+0x40/0x54
  worker_thread+0x1ec/0x2a8
  kthread+0x138/0x158
  ret_from_fork+0x10/0x20

Fix it by making sure there are any bits to mask out.

Fixes: 69aba7948cbe ("nvmem: Add a simple NVMEM framework for consumers")
Cc: Douglas Anderson &lt;dianders@chromium.org&gt;
Cc: stable@vger.kernel.org
Signed-off-by: Stephen Boyd &lt;swboyd@chromium.org&gt;
Signed-off-by: Srinivas Kandagatla &lt;srinivas.kandagatla@linaro.org&gt;
Link: https://lore.kernel.org/r/20211013124511.18726-1-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&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 5d388fa01fa6eb310ac023a363a6cb216d9d8fe9 upstream.

If a cell has 'nbits' equal to a multiple of BITS_PER_BYTE the logic

 *p &amp;= GENMASK((cell-&gt;nbits%BITS_PER_BYTE) - 1, 0);

will become undefined behavior because nbits modulo BITS_PER_BYTE is 0, and we
subtract one from that making a large number that is then shifted more than the
number of bits that fit into an unsigned long.

UBSAN reports this problem:

 UBSAN: shift-out-of-bounds in drivers/nvmem/core.c:1386:8
 shift exponent 64 is too large for 64-bit type 'unsigned long'
 CPU: 6 PID: 7 Comm: kworker/u16:0 Not tainted 5.15.0-rc3+ #9
 Hardware name: Google Lazor (rev3+) with KB Backlight (DT)
 Workqueue: events_unbound deferred_probe_work_func
 Call trace:
  dump_backtrace+0x0/0x170
  show_stack+0x24/0x30
  dump_stack_lvl+0x64/0x7c
  dump_stack+0x18/0x38
  ubsan_epilogue+0x10/0x54
  __ubsan_handle_shift_out_of_bounds+0x180/0x194
  __nvmem_cell_read+0x1ec/0x21c
  nvmem_cell_read+0x58/0x94
  nvmem_cell_read_variable_common+0x4c/0xb0
  nvmem_cell_read_variable_le_u32+0x40/0x100
  a6xx_gpu_init+0x170/0x2f4
  adreno_bind+0x174/0x284
  component_bind_all+0xf0/0x264
  msm_drm_bind+0x1d8/0x7a0
  try_to_bring_up_master+0x164/0x1ac
  __component_add+0xbc/0x13c
  component_add+0x20/0x2c
  dp_display_probe+0x340/0x384
  platform_probe+0xc0/0x100
  really_probe+0x110/0x304
  __driver_probe_device+0xb8/0x120
  driver_probe_device+0x4c/0xfc
  __device_attach_driver+0xb0/0x128
  bus_for_each_drv+0x90/0xdc
  __device_attach+0xc8/0x174
  device_initial_probe+0x20/0x2c
  bus_probe_device+0x40/0xa4
  deferred_probe_work_func+0x7c/0xb8
  process_one_work+0x128/0x21c
  process_scheduled_works+0x40/0x54
  worker_thread+0x1ec/0x2a8
  kthread+0x138/0x158
  ret_from_fork+0x10/0x20

Fix it by making sure there are any bits to mask out.

Fixes: 69aba7948cbe ("nvmem: Add a simple NVMEM framework for consumers")
Cc: Douglas Anderson &lt;dianders@chromium.org&gt;
Cc: stable@vger.kernel.org
Signed-off-by: Stephen Boyd &lt;swboyd@chromium.org&gt;
Signed-off-by: Srinivas Kandagatla &lt;srinivas.kandagatla@linaro.org&gt;
Link: https://lore.kernel.org/r/20211013124511.18726-1-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
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