linux/drivers/reset/core.c, branch v5.1

reset: fix null pointer dereference on dev by dev_name

2019-01-07T15:38:26Z

The call to dev_name will dereference dev, however, dev is later being null checked, so there is a possibility of a null pointer dereference on dev by the call to dev_name. Fix this by null checking dev first before the call to dev_name Detected by CoverityScan, CID#1475475 ("Dereference before null check") Fixes: 2a6cb2b1d83b ("reset: Add reset_control_get_count()") Signed-off-by: Colin Ian King Signed-off-by: Philipp Zabel

reset: Add reset_control_get_count()

2019-01-07T15:38:26Z

Currently the reset core has internal support for counting the number of resets for a device described in DT. Generalize this to devices using lookup resets, and export it for public use. This will be used by generic drivers that need to be sure a device is controlled by a single, dedicated reset line (e.g. vfio-platform). Signed-off-by: Geert Uytterhoeven [p.zabel@pengutronix.de: fixed a typo in reset_control_get_count comment] Signed-off-by: Philipp Zabel

reset: Fix potential use-after-free in __of_reset_control_get()

2018-10-08T13:25:21Z

Calling of_node_put() decreases the reference count of a device tree object, and may free some data. However, the of_phandle_args structure embedding it is passed to reset_controller_dev.of_xlate() after that, so it may still be accessed. Move the call to of_node_put() down to fix this. Signed-off-by: Geert Uytterhoeven [p.zabel@pengutronix.de: moved of_node_put after mutex_unlock] Signed-off-by: Philipp Zabel

treewide: Use struct_size() for kmalloc()-family

2018-06-06T18:15:43Z

One of the more common cases of allocation size calculations is finding the size of a structure that has a zero-sized array at the end, along with memory for some number of elements for that array. For example: struct foo { int stuff; void *entry[]; }; instance = kmalloc(sizeof(struct foo) + sizeof(void *) * count, GFP_KERNEL); Instead of leaving these open-coded and prone to type mistakes, we can now use the new struct_size() helper: instance = kmalloc(struct_size(instance, entry, count), GFP_KERNEL); This patch makes the changes for kmalloc()-family (and kvmalloc()-family) uses. It was done via automatic conversion with manual review for the "CHECKME" non-standard cases noted below, using the following Coccinelle script: // pkey_cache = kmalloc(sizeof *pkey_cache + tprops->pkey_tbl_len * // sizeof *pkey_cache->table, GFP_KERNEL); @@ identifier alloc =~ "kmalloc|kzalloc|kvmalloc|kvzalloc"; expression GFP; identifier VAR, ELEMENT; expression COUNT; @@ - alloc(sizeof(*VAR) + COUNT * sizeof(*VAR->ELEMENT), GFP) + alloc(struct_size(VAR, ELEMENT, COUNT), GFP) // mr = kzalloc(sizeof(*mr) + m * sizeof(mr->map[0]), GFP_KERNEL); @@ identifier alloc =~ "kmalloc|kzalloc|kvmalloc|kvzalloc"; expression GFP; identifier VAR, ELEMENT; expression COUNT; @@ - alloc(sizeof(*VAR) + COUNT * sizeof(VAR->ELEMENT[0]), GFP) + alloc(struct_size(VAR, ELEMENT, COUNT), GFP) // Same pattern, but can't trivially locate the trailing element name, // or variable name. @@ identifier alloc =~ "kmalloc|kzalloc|kvmalloc|kvzalloc"; expression GFP; expression SOMETHING, COUNT, ELEMENT; @@ - alloc(sizeof(SOMETHING) + COUNT * sizeof(ELEMENT), GFP) + alloc(CHECKME_struct_size(&SOMETHING, ELEMENT, COUNT), GFP) Signed-off-by: Kees Cook

reset: modify the way reset lookup works for board files

2018-03-27T08:39:47Z

Commit 7af1bb19f1d7 ("reset: add support for non-DT systems") introduced reset control lookup mechanism for boards that still use board files. The routine used to register lookup entries takes the corresponding reset_controlled_dev structure as argument. It's been determined however that for the first user of this new interface - davinci psc driver - it will be easier to register the lookup entries using the reset controller device name. This patch changes the way lookup entries are added. Signed-off-by: Bartosz Golaszewski [p.zabel@pengutronix.de: added missing ERR_PTR] Signed-off-by: Philipp Zabel

reset: add support for non-DT systems

2018-03-27T08:39:47Z

The reset framework only supports device-tree. There are some platforms however, which need to use it even in legacy, board-file based mode. An example of such architecture is the DaVinci family of SoCs which supports both device tree and legacy boot modes and we don't want to introduce any regressions. We're currently working on converting the platform from its hand-crafted clock API to using the common clock framework. Part of the overhaul will be representing the chip's power sleep controller's reset lines using the reset framework. This changeset extends the core reset code with a new reset lookup entry structure. It contains data allowing the reset core to associate reset lines with devices by comparing the dev_id and con_id strings. It also provides a function allowing drivers to register lookup entries with the framework. The new lookup function is only called as a fallback in case the of_node field is NULL and doesn't change anything for current users. Tested with a dummy reset driver with several lookup entries. An example lookup table registration from a driver can be found below: static struct reset_control_lookup foobar_reset_lookup[] = { RESET_LOOKUP("foo.0", "foo", 15), RESET_LOOKUP("bar.0", NULL, 5), }; foobar_probe() { ... reset_controller_add_lookup(&rcdev, foobar_reset_lookup, ARRAY_SIZE(foobar_reset_lookup)); ... } Cc: Sekhar Nori Cc: Kevin Hilman Cc: David Lechner Signed-off-by: Bartosz Golaszewski Signed-off-by: Philipp Zabel

reset: make device_reset_optional() really optional

2017-11-27T08:16:39Z

Commit bb475230b8e5 ("reset: make optional functions really optional") converted *_get_optional* functions, but device_reset_optional() was left behind. Convert it in the same way. Signed-off-by: Masahiro Yamada Signed-off-by: Philipp Zabel

reset: make (de)assert report success for self-deasserting reset drivers

2017-07-19T10:10:48Z

By now there are drivers using shared reset controls and (de)assert calls on platforms with self-deasserting reset lines and thus reset drivers that do not implement .assert() and .deassert(). As long as the initial state of the reset line is deasserted, there is no reason for a reset_control_assert call to return an error for shared reset controls, or for a reset_control_deassert call to return an error for either shared or exclusive reset controls: after a call to reset_control_deassert the reset line is guaranteed to be deasserted, and after a call to reset_control_assert it is valid for the reset line to stay deasserted for shared reset controls. Signed-off-by: Philipp Zabel Reviewed-by: Linus Walleij

reset: Add APIs to manage array of resets

2017-07-19T08:28:12Z

Many devices may want to request a bunch of resets and control them. So it's better to manage them as an array. Add APIs to _get() an array of reset_control, reusing the _assert(), _deassert(), and _reset() APIs for single reset controls. Since reset controls already may control multiple reset lines with a single hardware bit, from the user perspective, reset control arrays are not at all different from single reset controls. Note that these APIs don't guarantee that the reset lines managed in the array are handled in any particular order. Cc: Felipe Balbi Cc: Jon Hunter Signed-off-by: Vivek Gautam [p.zabel@pengutronix.de: changed API to hide reset control arrays behind struct reset_control] Signed-off-by: Philipp Zabel

reset: use kref for reference counting

2017-06-06T07:39:20Z

Use kref for reference counting and enjoy the advantages of refcount_t. Signed-off-by: Philipp Zabel