From: Ian Abbott Date: Fri, 30 Jan 2026 16:47:26 +0000 (+0000) Subject: comedi: add comedi_check_request_region() X-Git-Tag: v7.1-rc1~17^2~107 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=241cb8dee0f83856c728f4fe2c29e331386c92f2;p=thirdparty%2Fkernel%2Flinux.git comedi: add comedi_check_request_region() There is an existing comedi_request_region(dev, start, len) function used by COMEDI drivers for legacy devices to request an I/O port region starting at a specified base address (which must be non-zero) and with a specified length. It uses request_region(). On success, it sets dev->iobase and dev->iolen and returns 0. There is a alternative function __comedi_request_region(dev, start, len) which does the same thing without setting dev->iobase and dev->iolen. Most hardware devices have restrictions on the allowed I/O port base address and alignment, so add new functions comedi_check_request_region(dev, start, len, minstart, maxend, minalign) and __comedi_check_request_region(dev, start, len, minstart, maxend, minalign) to perform these additional checks. Turn the original functions into static inline wrapper functions that call the new functions. Signed-off-by: Ian Abbott Link: https://patch.msgid.link/20260130170416.49994-2-abbotti@mev.co.uk Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/comedi/drivers.c b/drivers/comedi/drivers.c index db225a3bf0128..5b02107bb6bfe 100644 --- a/drivers/comedi/drivers.c +++ b/drivers/comedi/drivers.c @@ -933,19 +933,24 @@ int comedi_load_firmware(struct comedi_device *dev, EXPORT_SYMBOL_GPL(comedi_load_firmware); /** - * __comedi_request_region() - Request an I/O region for a legacy driver + * __comedi_check_request_region() - Request an I/O region for a legacy driver * @dev: COMEDI device. * @start: Base address of the I/O region. * @len: Length of the I/O region. + * @minstart: Minimum allowed start address of region. + * @maxend: Maximum allowed region end address of region. + * @minalign: Required alignment for base address. * * Requests the specified I/O port region which must start at a non-zero - * address. + * address, must fall within specified bounds, and must be correctly aligned. * * Returns 0 on success, -EINVAL if @start is 0, or -EIO if the request * fails. */ -int __comedi_request_region(struct comedi_device *dev, - unsigned long start, unsigned long len) +int __comedi_check_request_region(struct comedi_device *dev, + unsigned long start, unsigned long len, + unsigned long minstart, unsigned long maxend, + unsigned long minalign) { if (!start) { dev_warn(dev->class_dev, @@ -954,6 +959,19 @@ int __comedi_request_region(struct comedi_device *dev, return -EINVAL; } + if (start < minstart || start > maxend || maxend - start < len - 1) { + dev_warn(dev->class_dev, + "%s: I/O base address or length out of range\n", + dev->board_name); + return -EINVAL; + } + if (!IS_ALIGNED(start, minalign)) { + dev_warn(dev->class_dev, + "%s: I/O base address not correctly aligned\n", + dev->board_name); + return -EINVAL; + } + if (!request_region(start, len, dev->board_name)) { dev_warn(dev->class_dev, "%s: I/O port conflict (%#lx,%lu)\n", dev->board_name, start, len); @@ -962,16 +980,19 @@ int __comedi_request_region(struct comedi_device *dev, return 0; } -EXPORT_SYMBOL_GPL(__comedi_request_region); +EXPORT_SYMBOL_GPL(__comedi_check_request_region); /** - * comedi_request_region() - Request an I/O region for a legacy driver + * comedi_check_request_region() - Request an I/O region for a legacy driver * @dev: COMEDI device. * @start: Base address of the I/O region. * @len: Length of the I/O region. + * @minstart: Minimum allowed start address of region. + * @maxend: Maximum allowed region end address of region. + * @minalign: Required alignment for base address. * * Requests the specified I/O port region which must start at a non-zero - * address. + * address, must fall within specified bounds, and must be correctly aligned. * * On success, @dev->iobase is set to the base address of the region and * @dev->iolen is set to its length. @@ -979,12 +1000,15 @@ EXPORT_SYMBOL_GPL(__comedi_request_region); * Returns 0 on success, -EINVAL if @start is 0, or -EIO if the request * fails. */ -int comedi_request_region(struct comedi_device *dev, - unsigned long start, unsigned long len) +int comedi_check_request_region(struct comedi_device *dev, + unsigned long start, unsigned long len, + unsigned long minstart, unsigned long maxend, + unsigned long minalign) { int ret; - ret = __comedi_request_region(dev, start, len); + ret = __comedi_check_request_region(dev, start, len, minstart, maxend, + minalign); if (ret == 0) { dev->iobase = start; dev->iolen = len; @@ -992,7 +1016,7 @@ int comedi_request_region(struct comedi_device *dev, return ret; } -EXPORT_SYMBOL_GPL(comedi_request_region); +EXPORT_SYMBOL_GPL(comedi_check_request_region); /** * comedi_legacy_detach() - A generic (*detach) function for legacy drivers diff --git a/include/linux/comedi/comedidev.h b/include/linux/comedi/comedidev.h index 35fdc41845cee..577a08f37aeeb 100644 --- a/include/linux/comedi/comedidev.h +++ b/include/linux/comedi/comedidev.h @@ -1026,10 +1026,55 @@ int comedi_load_firmware(struct comedi_device *dev, struct device *hw_dev, unsigned long context), unsigned long context); -int __comedi_request_region(struct comedi_device *dev, - unsigned long start, unsigned long len); -int comedi_request_region(struct comedi_device *dev, - unsigned long start, unsigned long len); +int __comedi_check_request_region(struct comedi_device *dev, + unsigned long start, unsigned long len, + unsigned long minstart, unsigned long maxend, + unsigned long minalign); +int comedi_check_request_region(struct comedi_device *dev, + unsigned long start, unsigned long len, + unsigned long minstart, unsigned long maxend, + unsigned long minalign); + +/** + * __comedi_request_region() - Request an I/O region for a legacy driver + * @dev: COMEDI device. + * @start: Base address of the I/O region. + * @len: Length of the I/O region. + * + * Requests the specified I/O port region which must start at a non-zero + * address. + * + * Returns 0 on success, -EINVAL if @start is 0, or -EIO if the request + * fails. + */ +static inline int __comedi_request_region(struct comedi_device *dev, + unsigned long start, + unsigned long len) +{ + return __comedi_check_request_region(dev, start, len, 0, ~0ul, 1); +} + +/** + * comedi_request_region() - Request an I/O region for a legacy driver + * @dev: COMEDI device. + * @start: Base address of the I/O region. + * @len: Length of the I/O region. + * + * Requests the specified I/O port region which must start at a non-zero + * address. + * + * On success, @dev->iobase is set to the base address of the region and + * @dev->iolen is set to its length. + * + * Returns 0 on success, -EINVAL if @start is 0, or -EIO if the request + * fails. + */ +static inline int comedi_request_region(struct comedi_device *dev, + unsigned long start, unsigned long len) +{ + return comedi_check_request_region(dev, start, len, 0, ~0ul, 1); +} + void comedi_legacy_detach(struct comedi_device *dev); int comedi_auto_config(struct device *hardware_device,