Identifying firmware functions executed in a call chain prior to the occurrence of an error condition
Technologies are disclosed for identifying firmware functions that were executed in a call chain prior to the occurrence of an error condition, such as an assert or an exception. In particular, a search is made from an instruction pointer (“IP”) for a memory address containing a signature identifying a firmware module. The firmware module that includes a function that generated the error condition can be identified based on the memory address. The name of the function that generated the error condition can be identified using a function mapping file. Previous functions in the same call chain are identified and their names determined using the function mapping file. Output can then be generated that includes the name of the firmware module that includes the function that generated the error condition, the name of the function that generated the error condition, and the names of other functions in the same call chain.
1. A computer-implemented method, comprising:
searching boundaries of a memory of a computing device for a memory address containing a signature, the search beginning at a memory address specified by an instruction pointer (IP) when an error condition occurred at the computing device;
identifying a firmware module of a firmware executing on the computing device that includes a function that generated the error condition based, at least in part, on the memory address containing the signature;
identifying a name of the function that generated the error condition from a plurality of functions in the firmware module using a function mapping file, the function mapping file comprising a memory address for each of the plurality of functions in the firmware module and data identifying a name of each of the plurality of functions in the firmware module;
identifying one or more functions in a call chain that includes the function that generated the error, the one or more functions being previous in the call chain to the function that generated the error;
identifying names of the one or more functions in the call chain using the function mapping file; and
outputting, from the computing device, a name of the firmware module, a name of the function that generated the error condition, and the names of the one or more functions in the call chain.
2. The computer-implemented method of claim 1 , wherein the error condition comprises an assert or an exception.
3. The computer-implemented method of claim 1 , wherein the function mapping file is generated at a build time of the firmware module.
4. The computer-implemented method of claim 1 , wherein the firmware executes on the computing device in a Pre-EFI Initialization (PEI) phase of operation.
5. The computer-implemented method of claim 1 , wherein the firmware executes on the computing device in a Driver Execution Environment (DXE) phase of operation.
6. The computer-implemented method of claim 1 , wherein the one or more functions in the call chain are identified using unwind data.
7. The computer-implemented method of claim 1 , wherein the one or more functions in the call chain are identified using stack frames.
8. A non-transitory computer-readable storage medium having computer-executable instructions stored thereupon which, when executed by a computing device, cause the computing device to:
search boundaries of a memory of the computing device for a memory address containing a signature, the search beginning at a memory address specified by an instruction pointer (IP) when an error condition occurred at the computing device;
identify a firmware module of a firmware executing on the computing device that includes a function that generated the error condition based, at least in part, on the memory address containing the signature;
identify a name of the function that generated the error condition from a plurality of functions in the firmware module using a function mapping file, the function mapping file comprising a memory address for each of the plurality of functions in the firmware module and data identifying a name of each of the plurality of functions in the firmware module;
identify one or more functions in a call chain that includes the function that generated the error, the one or more functions being previous in the call chain to the function that generated the error;
identify names of the one or more functions in the call chain using the function mapping file; and
output, from the computing device, a name of the firmware module, a name of the function that generated the error condition, and the names of the one or more functions in the call chain.
9. The non-transitory computer-readable storage medium of claim 8 , wherein the error condition comprises an assert or an exception.
10. The non-transitory computer-readable storage medium of claim 8 , wherein the function mapping file is generated at a build time of the firmware module.
11. The non-transitory computer-readable storage medium of claim 8 , wherein the firmware executes on the computing device in a Pre-EFI Initialization (PEI) phase of operation.
12. The non-transitory computer-readable storage medium of claim 8 , wherein the firmware executes on the computing device in a Driver Execution Environment (DXE) phase of operation.
13. The non-transitory computer-readable storage medium of claim 8 , wherein the one or more functions in the call chain are identified using unwind data.
14. The non-transitory computer-readable storage medium of claim 9 , wherein the one or more functions in the call chain are identified using stack frames.
15. A computing device, comprising:
one or more processors;
a memory; and
at least one non-transitory computer-readable storage medium having computer-executable instructions stored thereupon which, when executed by the one or more processors, cause the computing device to:
search boundaries of the memory for a memory address containing a signature, the search beginning at a memory address specified by an instruction pointer (IP) when an error condition occurred at the computing device;
identify a firmware module of a firmware executing on the computing device that includes a function that generated the error condition based, at least in part, on the memory address containing the signature;
identify a name of the function that generated the error condition from a plurality of functions in the firmware module using a function mapping file, the function mapping file comprising a memory address for each of the plurality of functions in the firmware module and data identifying a name of each of the plurality of functions in the firmware module;
identify one or more functions in a call chain that includes the function that generated the error, the one or more functions being previous in the call chain to the function that generated the error;
identify names of the one or more functions in the call chain using the function mapping file; and
output, from the computing device, a name of the firmware module, a name of the function that generated the error condition, and the names of the one or more functions in the call chain.
16. The computing system of claim 15 , wherein the error condition comprises an assert or an exception.
17. The computing system of claim 15 , wherein the function mapping file is generated at a build time of the firmware module.
18. The computing system of claim 15 , wherein the firmware executes on the computing device in a Pre-EFI Initialization (PEI) phase of operation or a Driver Execution Environment (DXE) phase of operation.
19. The computing system of claim 15 , wherein the one or more functions in the call chain are identified using unwind data.
20. The computing system of claim 15 , wherein the one or more functions in the call chain are identified using stack frames.