Executing a kernel device driver as a user space process

• US 9,619,308 B2
• Filed: 05/23/2016
• Issued: 04/11/2017
• Est. Priority Date: 11/18/2010
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Adda, Michael, Aloni, Dan, Braverman, Avner
• Primary Examiner(s): Wathen, Brian W
• Application Number:
  US15/161,469
• Publication Number:
  US 20160266946A1
• Time in Patent Office: 323 Days
• CPC Class Codes: G06F 11/0715 in a system implementing multitasking multitasking per se G06F9/46
• CPC Class Codes: G06F 11/0793 Remedial or corrective actions recovery from an exception in an instruction pipeline G06F9/3861; by retry G06F11/1402; for recovering from a failure of a protocol instance or entity H04L69/40
• CPC Class Codes: G06F 11/1402 Saving, restoring, recovering or retrying
• CPC Class Codes: G06F 13/102 where the programme performs an interfacing function, e.g. device driver G06F13/105 takes precedence; scheduling within device drivers G06F9/52; contention policies within device drivers G06F9/4881
• CPC Class Codes: G06F 13/24 using interrupt G06F13/32 takes precedence
• CPC Class Codes: G06F 13/28 using burst mode transfer, e.g. direct memory access DMA, cycle steal G06F13/32 takes precedence
• CPC Class Codes: G06F 13/4282 on a serial bus, e.g. I2C bus, SPI bus on daisy chain buses G06F13/4247
• CPC Class Codes: G06F 9/4843 by program, e.g. task dispatcher, supervisor, operating system
• CPC Class Codes: G06F 9/541 via adapters, e.g. between incompatible applications
• CPC Class Codes: G06F 9/545 where tasks reside in different layers, e.g. user- and kernel-space

Abstract

A method, including receiving, by a user space driver framework (UDF) library executing from a user space of a memory over a monolithic operating system kernel, a kernel application programming interface (API) call from a device driver executing from the user space. The UDF library then performs an operation corresponding to the kernel API call.

Claims

1. A method, comprising:

receiving, by a user space driver framework (UDF) library executing from a user space of a memory over an operating system kernel operated by a device driver executing from the user space, a kernel application programming interface (API) call from a device driver executing from the user space;

determining that the operation comprises a privileged operation, wherein when the operation is privileged;

conveying, via a file descriptor, the API call to a UDF kernel module executing from a kernel space of the memory over the operating system kernel; and

when the operation is non-privileged;

performing, by the UDF library, an operation corresponding to the kernel API call, and

detecting an interrupt and sending a notification of the interrupt via the file descriptor to the UDF library, wherein upon receiving the notification;

scheduling by a scheduler an execution of an interrupt handling of the interrupt handling code of the device driver.

2. The method according to claim 1, further including, when the operation is privileged, performing, by a kernel space emulation module, the privileged operation from the kernel space while conveying completion information back to the UDF library.

3. The method according to claim 1, wherein the non-privileged operation is selected from a group of operations comprising maintaining a list, maintaining a timer, and maintaining a process scheduler.

4. The method according to claim 1, wherein the privileged operation is selected from a group of operations comprising catching an interrupt, allocating direct memory access (DMA) memory, and mapping input/output (I/O) memory addresses.

5. The method according to claim 1, wherein the device driver comprises a Peripheral Component Interconnect (PCI) device driver.

6. A computer program product, the computer program product comprising:

a non-transitory computer readable storage medium having computer readable program code embodied therewith, the computer readable program code comprising;

computer readable program code configured to receive, by a user space driver framework (UDF) library executing from a user space of a memory over an operating system kernel operated by a device driver executing from the user space, a kernel application programming interface (API) call from a device driver executing from the user space; and

computer readable program code configured to determine that the operation comprises a privileged operation, wherein when the operation is privileged, the API call is conveyed, via a file descriptor, to a UDF kernel module executing from a kernel space of the memory over the operating system kernel; and

when the operation is non-privileged;

computer readable program code configured to perform, by the UDF library, an operation corresponding to the kernel API call, and

computer readable program code configured to detect an interrupt and sending a notification of the interrupt via the file descriptor to the UDF library, wherein upon receiving the notification;

scheduling by a scheduler an execution of an interrupt handling of the interrupt handling code of the device driver.

7. The computer program product according to claim 6, wherein the computer readable program code is configured to, when the operation is privileged, perform, by a kernel space emulation module, the privileged operation from the kernel space while conveying completion information back to the UDF library.

8. The computer program product according to claim 6, wherein the computer readable program code is configured to select the non-privileged operation from a group of operations comprising maintaining a list, maintaining a timer, and maintaining a process scheduler.

9. The computer program product according to claim 6, wherein the computer readable program code is configured to select the privileged operation from a group of operations comprising catching an interrupt, allocating direct memory access (DMA) memory, and mapping input/output (I/O) memory addresses.

10. The computer program product according to claim 6, wherein the device driver comprises a Peripheral Component Interconnect (PCI) device driver.